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Sample records for dengue em larvas

  1. Dengue

    MedlinePlus

    Dengue is an infection caused by a virus. You can get it if an infected mosquito bites you. Dengue does not spread from person to person. It ... the world. Outbreaks occur in the rainy season. Dengue is rare in the United States. Symptoms include ...

  2. Dengue

    MedlinePlus

    ... Epidemiology Transmission, information on epidemics and stats... Entomology & Ecology Mosquito that spreads dengue and its ecology... Clinical & Laboratory Guidance Tools for clinicians and laboratorians... ...

  3. Dengue

    MedlinePlus

    ... the hospital and get fluids. To lower your risk when traveling to areas where dengue is found Wear insect repellent with DEET Wear clothes that cover your arms, legs and feet Close unscreened doors and windows NIH: National Institute of Allergy and Infectious Diseases

  4. Bioactivity of seagrass against the dengue fever mosquito Aedes aegypti larvae

    PubMed Central

    Ali, M Syed; Ravikumar, S; Beula, J Margaret

    2012-01-01

    Objective To identify the larvicidal activity of the seagrass extracts. Methods Seagrass extracts, Syringodium isoetifolium (S. isoetifolium), Cymodocea serrulata and Halophila beccarii, were dissolved in DMSO to prepare a graded series of concentration. Batches of 25 early 4th instars larvae of Aedes aegypti (Ae. aegypti) were transferred to 250 mL enamel bowl containing 199 mL of distilled water and 1 mL of plant extracts (0.01 mg – 0.1 mg). After 24 h the mortality rate was identified with the formulae [(% of test mortality – % of control mortality)/(100 – % of control mortality)] × 100. Each experiment was conducted with three replicates and a concurrent control group. A control group consisted of 1 mL of DMSO and 199 mL of distilled water only. Results : The root extract of S. isoetifolium showed maximum larvicidal activity with minimum concentration of extract of LC50= 0.0 604 ± 0.0 040)µg/mL with lower confidence limit (LCL) – upper confidence limit (UCL) = (0.051–0.071) and LC90=0.0 972µg/mL followed by leaf extract of S. isoetifolium showed LC50= (0.062 ± 0.005)µg/mL. The regression equation of root and leaf extract of S. isoetifolium for 4th instar larvae were Y= 4.909 + 1.32x (R2= 0.909) and Y= 2.066 + 1.21x (R2 =0.897) respectively. The results of the preliminary phytochemical constituents shows the presence of saponin, steroids, terpenoid, phenols, protein and sugars. Conclusions From the present study the ethanolic extracts of seagrass of S. isoetifolium possesses lead compound for development of larvicidal activity. PMID:23569973

  5. Effect of mycosynthesized silver nanoparticles from filtrate of Trichoderma harzianum against larvae and pupa of dengue vector Aedes aegypti L.

    PubMed

    Sundaravadivelan, Chandran; Padmanabhan, Madanagopal Nalini

    2014-03-01

    Mosquitoes transmit dreadful diseases, causing millions of deaths every year. Therefore, screening for larvicidal and pupicidal activity of microbial extracts attributes could lead to development of new and improved mosquito control methods that are economical and safe for nontarget organisms and are ecofriendly. Synthetic chemical insecticides occupy predominant position in control strategies. These hazardous chemicals exert unwarranted toxicity and lethal effects on nontarget organisms, develop physiological resistance in target, and cause adverse environmental effect. For vector control, fungal-mediated natural products have been a priority in this area at present. In the current study, effective larvicidal and pupicidal effect of mycosynthesized silver nanoparticles (Ag NPs) using an entomopathogenic fungi Trichoderma harzianum against developmental stages of the dengue vector Aedes aegypti was investigated. An attractive possibility of green nanotechnology is to use microorganisms in the synthesis of nanosilver especially Ag NPs. The mycosynthesized Ag NPs were characterized to find their unique properties through UV-visible spectrophotometer, X-ray diffraction analysis, Fourier transform infrared, and surface characteristics by scanning electron microscopy. To analyze the bioefficacy, different test concentrations for extracellular filtrate (0.2, 0.4, 0.6, 0.8, and 1.0 %) and Ag NPs (0.05, 0.10, 0.15, 0.20, and 0.25 %) were prepared to a final volume of 200 mL using deionized water; 20 larvae of each instars (I-IV) and pupa were exposed to each test concentration separately which included a set of control (distilled water) group with five replicates. Characterization of the synthesized Ag NPs were about 10-20 nm without aggregation. Susceptibility of larval instars to synthesized Ag NPs was higher than the extracellular filtrate of T. harzianum alone after 24-h exposure, where the highest mortality was recorded as 92 and 96 % for first and second instars and

  6. Dengue Epidemiology

    MedlinePlus

    ... the southern U. S., dengue is endemic in northern Mexico, and the U.S. population has no immunity, the ... south Texas in 2005. (Dengue Hemorrhagic Fever - U.S.- Mexico Border, 2005 ) A small dengue outbreak occurred in ...

  7. Transport and retention of flounder larvae ( Platichthys flesus L.) in the Dollard nursery (Ems estuary)

    NASA Astrophysics Data System (ADS)

    Jager, Zwanette

    2001-05-01

    Variability in tidal transport of larval flounder ( Platichthys flesus L.) in the Dollard was investigated to estimate the quantity of larvae that are annually retained in the nursery based on simultaneous measurements of water transport and larval concentrations. Sampling was done three times per hour in the main channel in the Dollard, during 35 tidal cycles divided over 1993, 1994 and 1995. In 1993, additional sampling was carried out simultaneously during eight tidal cycles in a subsidiary channel. Larval concentrations showed marked tidal variations at all time scales and indicated a patchy spatial distribution. The estimated net tidal transport of larvae was not correlated to the net tidal transport of water. However, a higher net water transport coincided with higher retention, defined as the percentage of net larval transport divided by the flood larval transport. Also, relatively longer duration of the flood than the ebb period (tidal asymmetry) was positively correlated with both net tidal water transport and larval retention. The wind direction significantly affected the net water transport at the cross-section in the main channel, whereas wind speed was not significant. The flood transport, but not the ebb or net transport, was significantly higher during spring tide following full moon than during the other lunar phases. The net tidal transport of larvae was much more variable in 1994 than in 1993 and 1995, frequently resulting in ebb surpluses in larval transport. Despite higher mean concentrations, the estimated net larval input was lower in 1994 than in 1993. This corresponded neither with the observed abundance estimates of juvenile flounder in the Dollard in these two years, nor with the abundance index obtained from routine surveys. The total larval input better reflects the juvenile flounder abundance. Variability in water circulation, influenced by varying wind conditions, and its effect on larval transport and retention is an important source

  8. Dengue Fever

    MedlinePlus

    ... away from areas that have a dengue fever epidemic, the risk of contracting dengue fever is small for international travelers./p> Reviewed by: Elana Pearl Ben-Joseph, ... Nile Virus First Aid: Vomiting Are Insect Repellents With DEET ...

  9. Dengue Fever

    MedlinePlus

    ... Search Button Leading research to understand, treat, and prevent infectious, immunologic, and allergic diseases NIAID Home Health & ... NIAID News & Events Volunteer NIAID > Health & Research Topics > Dengue Fever > Understanding Dengue Fever Understanding Cause Transmission Symptoms ...

  10. Dengue Fever

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dengue Fever” will be included in “Health Information for International Travel, 2007-2008” which will be published by the U.S. Centers for Disease Control and Prevention. Dengue and dengue hemorrhagic fever are viral diseases transmitted by Aedes mosquitoes. The disease is found in tropical and s...

  11. Multiple dengue virus types harbored by individual mosquitoes.

    PubMed

    Angel, Bennet; Angel, Annette; Joshi, Vinod

    2015-10-01

    The existing knowledge on pathogenesis and aetiology of DHF establishes that Dengue Hemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS) are caused by two subsequent infections of two different serotypes of dengue affecting a common human population with a time gap. Present studies have been undertaken on 212 laboratory reared infected individual mosquitoes from larvae collected from 31 dengue endemic towns of Rajasthan, India. Type specific DEN viruses were detected from individual mosquitoes employing RT-PCR. In 78.7% of 212 infected individual mosquitoes studied, vertically transmitted multiple DENV types were observed. We report for the first time that single mosquitoes contain multiple dengue virus types. PMID:26209106

  12. Dengue hemorrhagic fever

    MedlinePlus

    Hemorrhagic dengue; Dengue shock syndrome; Philippine hemorrhagic fever; Thai hemorrhagic fever; Singapore hemorrhagic fever ... Four different dengue viruses are known to cause dengue hemorrhagic fever. Dengue hemorrhagic fever occurs when a person is bitten by ...

  13. Dengue vaccine

    PubMed Central

    Jindal, Harashish; Bhatt, Bhumika; Malik, Jagbir Singh; SK, Shashikantha

    2014-01-01

    Dengue has emerged as one of the major global public health problems. The disease has broken out of its shell and has spread due to increased international travel and climatic changes. Globally, over 2.5 billion people accounting for >40% of the world's population are at risk from dengue. Since the 1940s, dengue vaccines have been under investigation. A live-attenuated tetravalent vaccine based on chimeric yellow fever-dengue virus (CYD-TDV) has progressed to phase III efficacy studies. Dengue vaccine has been found to be a cost-effective intervention to reduce morbidity and mortality. Current dengue vaccine candidates aim to protect against the 4 dengue serotypes, but the recent discovery of a fifth serotype could complicate vaccine development. In recent years, an urgent need has been felt for a vaccine to prevent the morbidity and mortality from this disease in a cost-effective way. PMID:25424928

  14. Dengue and Dengue Hemorrhagic Fever

    PubMed Central

    Gubler, Duane J.

    1998-01-01

    Dengue fever, a very old disease, has reemerged in the past 20 years with an expanded geographic distribution of both the viruses and the mosquito vectors, increased epidemic activity, the development of hyperendemicity (the cocirculation of multiple serotypes), and the emergence of dengue hemorrhagic fever in new geographic regions. In 1998 this mosquito-borne disease is the most important tropical infectious disease after malaria, with an estimated 100 million cases of dengue fever, 500,000 cases of dengue hemorrhagic fever, and 25,000 deaths annually. The reasons for this resurgence and emergence of dengue hemorrhagic fever in the waning years of the 20th century are complex and not fully understood, but demographic, societal, and public health infrastructure changes in the past 30 years have contributed greatly. This paper reviews the changing epidemiology of dengue and dengue hemorrhagic fever by geographic region, the natural history and transmission cycles, clinical diagnosis of both dengue fever and dengue hemorrhagic fever, serologic and virologic laboratory diagnoses, pathogenesis, surveillance, prevention, and control. A major challenge for public health officials in all tropical areas of the world is to devleop and implement sustainable prevention and control programs that will reverse the trend of emergent dengue hemorrhagic fever. PMID:9665979

  15. Dengue fever

    MedlinePlus

    ... by the bite of mosquitoes, most commonly the mosquito Aedes aegypti , which is found in tropic and ... Clothing, mosquito repellent, and netting can help reduce the risk of mosquito bites that can spread dengue fever and ...

  16. Dengue infection.

    PubMed

    Guzman, Maria G; Gubler, Duane J; Izquierdo, Alienys; Martinez, Eric; Halstead, Scott B

    2016-01-01

    Dengue is widespread throughout the tropics and local spatial variation in dengue virus transmission is strongly influenced by rainfall, temperature, urbanization and distribution of the principal mosquito vector Aedes aegypti. Currently, endemic dengue virus transmission is reported in the Eastern Mediterranean, American, South-East Asian, Western Pacific and African regions, whereas sporadic local transmission has been reported in Europe and the United States as the result of virus introduction to areas where Ae. aegypti and Aedes albopictus, a secondary vector, occur. The global burden of the disease is not well known, but its epidemiological patterns are alarming for both human health and the global economy. Dengue has been identified as a disease of the future owing to trends toward increased urbanization, scarce water supplies and, possibly, environmental change. According to the WHO, dengue control is technically feasible with coordinated international technical and financial support for national programmes. This Primer provides a general overview on dengue, covering epidemiology, control, disease mechanisms, diagnosis, treatment and research priorities. PMID:27534439

  17. Aedes aegypti Global Suitability Maps Using a Water Container Energy Balance Model for Dengue Risk Applications

    NASA Astrophysics Data System (ADS)

    Steinhoff, D.

    2015-12-01

    Dengue infections are estimated to total nearly 400 million per year worldwide, with both the geographic range and the magnitude of infections having increased in the past 50 years. The primary dengue vector mosquito Aedes aegypti is closely associated with humans. It lives exclusively in urban and semi-urban areas, preferentially bites humans, and spends its developmental stages in artificial water containers. Climate regulates the development of Ae. aegypti immature mosquitoes in artificial containers. Potential containers for Ae. aegypti immature development include, but are not limited to, small sundry items (e.g., bottles, cans, plastic containers), buckets, tires, barrels, tanks, and cisterns. Successful development of immature mosquitoes from eggs to larvae, pupae, and eventually adults is largely dependent on the availability of water and the thermal properties of the water in the containers. Recent work has shown that physics-based approaches toward modeling container water properties are promising for resolving the complexities of container water dynamics and the effects on immature mosquito development. An energy balance container model developed by the author, termed the Water Height And Temperature in Container Habitats Energy Model (WHATCH'EM), solves for water temperature and height for user-specified containers with readily available weather data. Here we use WHATCH'EM with NASA Earth Science products used as input to construct global suitability maps based on established water temperature ranges for immature Ae. aegypti mosquitoes. A proxy for dengue risk is provided from habitat suitability, but also population estimates, as Ae. aegypti is closely associated with human activity. NASA gridded Global Population of the World data is used to mask out rural areas with low dengue risk. Suitability maps are illustrated for a variety of containers (size, material, color) and shading scenarios.

  18. Dengue Fever Treatment

    MedlinePlus

    ... the MedlinePlus dengue site . Aegypti mosquito Credit: NIAID Biology & Transmission Dengue has emerged as a global health ... basic research activities aimed at better understanding the biology of the dengue virus, the progression of disease ...

  19. [Larva migrans].

    PubMed

    Chabasse, D; Le Clec'h, C; de Gentile, L; Verret, J L

    1995-01-01

    Larbish, cutaneous larva migrans or creeping eruption, is a serpiginous cutaneous eruption caused by skin penetration of infective larva from various animal nematodes. Hookworms (Ancylostoma brasiliense, A. caninum) are the most common causative parasites. They live in the intestines of dogs and cats where their ova are deposited in the animal feces. In sandy and shady soil, when temperature and moisture are elevated, the ova hatch and mature into infective larva. Infection occurs when humans have contact with the infected soil. Infective larva penetrate the exposed skin of the body, commonly around the feet, hands and buttocks. In humans, the larva are not able to complete their natural cycle and remain trapped in the upper dermis of the skin. The disease is widespread in tropical or subtropical regions, especially along the coast on sandy beaches. The diagnosis is easy for the patient who is returning from a tropical or subtropical climate and gives a history of beach exposure. The characteristic skin lesion is a fissure or erythematous cord which is displaced a few millimeters each day in a serpiginous track. Scabies, the larva currens syndrome due to Strongyloides stercoralis, must be distinguished from other creeping eruptions and subcutaneous swelling lesions caused by other nematodes or myiasis. Medical treatments are justified because it shortens the duration of the natural evolution of the disease. Topical tiabendazole is safe for localized invasions, but prolonged treatment may be necessary. Oral thiabendazole treatment for three days is effective, but sometimes is associated with adverse effects. Trials using albendazole for one or four consecutive days appear more efficacious. More recent trials using ivermectine showed that a single oral dose can cure 100% of the patients; thus, this drug looks very promising as a new form of therapy. Individual prophylaxis consists of avoiding skin contact with soil which has been contaminated with dog or cat feces

  20. Hypokalemic quadriparesis in dengue

    PubMed Central

    Mishra, Vikas; Harbada, Rishit; Sharma, Akhilesh; Mishra, Meenakshi

    2015-01-01

    Dengue infection is the leading cause of illness and death in tropical and subtropical regions of the world. The common complications associated with dengue fever are usual hematological abnormalities, shock, and organ failure. The neurological complications of dengue are uncommon. However, evidence of dengue virus neurotropism and complications has been slowly but surely rising as seen from increased literature on this subject over the last decade. We report an uncommon case of hypokalemic quadriparesis with dengue that had a favorable outcome. PMID:25949983

  1. Hypokalemic quadriparesis in dengue.

    PubMed

    Mishra, Vikas; Harbada, Rishit; Sharma, Akhilesh; Mishra, Meenakshi

    2015-01-01

    Dengue infection is the leading cause of illness and death in tropical and subtropical regions of the world. The common complications associated with dengue fever are usual hematological abnormalities, shock, and organ failure. The neurological complications of dengue are uncommon. However, evidence of dengue virus neurotropism and complications has been slowly but surely rising as seen from increased literature on this subject over the last decade. We report an uncommon case of hypokalemic quadriparesis with dengue that had a favorable outcome. PMID:25949983

  2. Dengue Knowledge and Preventive Practices in Iquitos, Peru.

    PubMed

    Paz-Soldán, Valerie A; Morrison, Amy C; Cordova Lopez, Jhonny J; Lenhart, Audrey; Scott, Thomas W; Elder, John P; Sihuincha, Moises; Kochel, Tadeusz J; Halsey, Eric S; Astete, Helvio; McCall, Philip J

    2015-12-01

    As part of a cluster-randomized trial to evaluate insecticide-treated curtains for dengue prevention in Iquitos, Peru, we surveyed 1,333 study participants to examine knowledge and reported practices associated with dengue and its prevention. Entomological data from 1,133 of these households were linked to the survey. Most participants knew that dengue was transmitted by mosquito bite (85.6%), but only few (18.6%) knew that dengue vectors bite during daytime. Most commonly recognized dengue symptoms were fever (86.6%), headache (76.4%), and muscle/joint pain (67.9%). Most commonly reported correct practices for mosquito control were cleaning homes (61.6%), using insecticide sprays (23%), and avoiding having standing water at home (12.3%). Higher education was associated with higher knowledge about dengue, including transmission and vector control. Higher socioeconomic status was associated with increased reported use of preventive practices requiring money expenditure. We were less likely to find Aedes aegypti eggs, larvae, or pupae in households that had < 5-year-old children at home. Although dengue has been transmitted in Iquitos since the 1990s and the Regional Health Authority routinely fumigates households, treats domestic water containers with larvicide, and issues health education messages through mass media, knowledge of dengue transmission and household practices for prevention could be improved. PMID:26503276

  3. Dengue Knowledge and Preventive Practices in Iquitos, Peru

    PubMed Central

    Paz-Soldán, Valerie A.; Morrison, Amy C.; Cordova Lopez, Jhonny J.; Lenhart, Audrey; Scott, Thomas W.; Elder, John P.; Sihuincha, Moises; Kochel, Tadeusz J.; Halsey, Eric S.; Astete, Helvio; McCall, Philip J.

    2015-01-01

    As part of a cluster-randomized trial to evaluate insecticide-treated curtains for dengue prevention in Iquitos, Peru, we surveyed 1,333 study participants to examine knowledge and reported practices associated with dengue and its prevention. Entomological data from 1,133 of these households were linked to the survey. Most participants knew that dengue was transmitted by mosquito bite (85.6%), but only few (18.6%) knew that dengue vectors bite during daytime. Most commonly recognized dengue symptoms were fever (86.6%), headache (76.4%), and muscle/joint pain (67.9%). Most commonly reported correct practices for mosquito control were cleaning homes (61.6%), using insecticide sprays (23%), and avoiding having standing water at home (12.3%). Higher education was associated with higher knowledge about dengue, including transmission and vector control. Higher socioeconomic status was associated with increased reported use of preventive practices requiring money expenditure. We were less likely to find Aedes aegypti eggs, larvae, or pupae in households that had < 5-year-old children at home. Although dengue has been transmitted in Iquitos since the 1990s and the Regional Health Authority routinely fumigates households, treats domestic water containers with larvicide, and issues health education messages through mass media, knowledge of dengue transmission and household practices for prevention could be improved. PMID:26503276

  4. Dengue viral infections

    PubMed Central

    Malavige, G; Fernando, S; Fernando, D; Seneviratne, S

    2004-01-01

    Dengue viral infections are one of the most important mosquito borne diseases in the world. They may be asymptomatic or may give rise to undifferentiated fever, dengue fever, dengue haemorrhagic fever (DHF), or dengue shock syndrome. Annually, 100 million cases of dengue fever and half a million cases of DHF occur worldwide. Ninety percent of DHF subjects are children less than 15 years of age. At present, dengue is endemic in 112 countries in the world. No vaccine is available for preventing this disease. Early recognition and prompt initiation of appropriate treatment are vital if disease related morbidity and mortality are to be limited. This review outlines aspects of the epidemiology of dengue infections, the dengue virus and its mosquito vector, clinical features and pathogenesis of dengue infections, and the management and control of these infections. PMID:15466994

  5. Dengue fever (image)

    MedlinePlus

    Dengue fever, or West Nile fever, is a mild viral illness transmitted by mosquitoes which causes fever, ... second exposure to the virus can result in Dengue hemorrhagic fever, a life-threatening illness.

  6. The dengue viruses.

    PubMed

    Henchal, E A; Putnak, J R

    1990-10-01

    Dengue, a major public health problem throughout subtropical and tropical regions, is an acute infectious disease characterized by biphasic fever, headache, pain in various parts of the body, prostration, rash, lymphadenopathy, and leukopenia. In more severe or complicated dengue, patients present with a severe febrile illness characterized by abnormalities of hemostasis and increased vascular permeability, which in some instances results in a hypovolemic shock. Four distinct serotypes of the dengue virus (dengue-1, dengue-2, dengue-3, and dengue-4) exist, with numerous virus strains found worldwide. Molecular cloning methods have led to a greater understanding of the structure of the RNA genome and definition of virus-specific structural and nonstructural proteins. Progress towards producing safe, effective dengue virus vaccines, a goal for over 45 years, has been made. PMID:2224837

  7. The dengue viruses.

    PubMed Central

    Henchal, E A; Putnak, J R

    1990-01-01

    Dengue, a major public health problem throughout subtropical and tropical regions, is an acute infectious disease characterized by biphasic fever, headache, pain in various parts of the body, prostration, rash, lymphadenopathy, and leukopenia. In more severe or complicated dengue, patients present with a severe febrile illness characterized by abnormalities of hemostasis and increased vascular permeability, which in some instances results in a hypovolemic shock. Four distinct serotypes of the dengue virus (dengue-1, dengue-2, dengue-3, and dengue-4) exist, with numerous virus strains found worldwide. Molecular cloning methods have led to a greater understanding of the structure of the RNA genome and definition of virus-specific structural and nonstructural proteins. Progress towards producing safe, effective dengue virus vaccines, a goal for over 45 years, has been made. Images PMID:2224837

  8. Dengue in Java, Indonesia: Relevance of Mosquito Indices as Risk Predictors

    PubMed Central

    Wijayanti, Siwi P. M.; Sunaryo, Sunaryo; Suprihatin, Suprihatin; McFarlane, Melanie; Rainey, Stephanie M.; Dietrich, Isabelle; Schnettler, Esther; Biek, Roman; Kohl, Alain

    2016-01-01

    Background No vaccine is currently available for dengue virus (DENV), therefore control programmes usually focus on managing mosquito vector populations. Entomological surveys provide the most common means of characterising vector populations and predicting the risk of local dengue virus transmission. Despite Indonesia being a country strongly affected by DENV, only limited information is available on the local factors affecting DENV transmission and the suitability of available survey methods for assessing risk. Methodology/principal findings We conducted entomological surveys in the Banyumas Regency (Central Java) where dengue cases occur on an annual basis. Four villages were sampled during the dry and rainy seasons: two villages where dengue was endemic, one where dengue cases occurred sporadically and one which was dengue-free. In addition to data for conventional larvae indices, we collected data on pupae indices, and collected adult mosquitoes for species identification in order to determine mosquito species composition and population density. Traditionally used larval indices (House indices, Container indices and Breteau indices) were found to be inadequate as indicators for DENV transmission risk. In contrast, species composition of adult mosquitoes revealed that competent vector species were dominant in dengue endemic and sporadic villages. Conclusions/significance Our data suggested that the utility of traditional larvae indices, which continue to be used in many dengue endemic countries, should be re-evaluated locally. The results highlight the need for validation of risk indicators and control strategies across DENV affected areas here and perhaps elsewhere in SE Asia. PMID:26967524

  9. Dengue fever: natural management.

    PubMed

    Qadir, Muhammad Imran; Abbas, Khizar; Tahir, Madeha; Irfan, Muhammad; Raza Bukhari, Syeda Fiza; Ahmed, Bilal; Hanif, Muhammad; Rasul, Akhtar; Ali, Muhammad

    2015-03-01

    Dengue fever is caused by the mosquito-borne dengue virus (DENV) serotypes 1-4, and is the most common arboviral infection of humans in subtropical and tropical regions of the world. Dengue virus infections can present with a spacious range of clinical signs, from a mild feverish illness to a life-threatening shock syndrome. Till now, there is no approved vaccine or drug against this virus. Therefore, there is an urgent need of development of alternative solutions for dengue. Several plant species have been reported with anti-dengue activity. Many herbal/natural drugs, most of which are commonly used as nutritional components, have been used as antiviral, larvicidal, mosquitocidal and mosquito repellents that may be used against dengue. The objective of this review article was to provide current approaches for the treatment and management/prevention of dengue fever by targeting viral proteins involved in replication cycle of the virus and different developmental stages of mosquito. PMID:25730815

  10. Dengue in India.

    PubMed

    Gupta, Nivedita; Srivastava, Sakshi; Jain, Amita; Chaturvedi, Umesh C

    2012-09-01

    Dengue virus belongs to family Flaviviridae, having four serotypes that spread by the bite of infected Aedes mosquitoes. It causes a wide spectrum of illness from mild asymptomatic illness to severe fatal dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS). Approximately 2.5 billion people live in dengue-risk regions with about 100 million new cases each year worldwide. The cumulative dengue diseases burden has attained an unprecedented proportion in recent times with sharp increase in the size of human population at risk. Dengue disease presents highly complex pathophysiological, economic and ecologic problems. In India, the first epidemic of clinical dengue-like illness was recorded in Madras (now Chennai) in 1780 and the first virologically proved epidemic of dengue fever (DF) occurred in Calcutta (now Kolkata) and Eastern Coast of India in 1963-1964. During the last 50 years a large number of physicians have treated and described dengue disease in India, but the scientific studies addressing various problems of dengue disease have been carried out at limited number of centres. Achievements of Indian scientists are considerable; however, a lot remain to be achieved for creating an impact. This paper briefly reviews the extent of work done by various groups of scientists in this country. PMID:23041731

  11. [Dengue and dengue hemorrhagic fever: research priorities].

    PubMed

    Guzmán, María G; García, Gissel; Kourí, Gustavo

    2006-03-01

    Dengue is one of the most important infectious diseases in tropical and subtropical countries. At present, the only strategy available to reduce the incidence of dengue is vector control. The World Health Organization and the Pan American Health Organization have called on all nations to take the needed steps to help diminish the burden of this disease and its medical and socioeconomic impact. It is hoped that it will be possible to reverse the increase in dengue and help control its spread through a coordinated, effective international response, along with epidemiological, clinical, and virological research that brings together the most advanced methods and techniques. This piece summarizes the most up-to-date information on dengue, analyzes current epidemiologic trends in the Region of the Americas, discusses the main global and Western Hemisphere initiatives to control the disease, and presents the main areas of research that should be developed in the immediate future. PMID:16640849

  12. Dengue virus vaccine development.

    PubMed

    Yauch, Lauren E; Shresta, Sujan

    2014-01-01

    Dengue virus (DENV) is a significant cause of morbidity and mortality in tropical and subtropical regions, causing hundreds of millions of infections each year. Infections range from asymptomatic to a self-limited febrile illness, dengue fever (DF), to the life-threatening dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). The expanding of the habitat of DENV-transmitting mosquitoes has resulted in dramatic increases in the number of cases over the past 50 years, and recent outbreaks have occurred in the United States. Developing a dengue vaccine is a global health priority. DENV vaccine development is challenging due to the existence of four serotypes of the virus (DENV1-4), which a vaccine must protect against. Additionally, the adaptive immune response to DENV may be both protective and pathogenic upon subsequent infection, and the precise features of protective versus pathogenic immune responses to DENV are unknown, complicating vaccine development. Numerous vaccine candidates, including live attenuated, inactivated, recombinant subunit, DNA, and viral vectored vaccines, are in various stages of clinical development, from preclinical to phase 3. This review will discuss the adaptive immune response to DENV, dengue vaccine challenges, animal models used to test dengue vaccine candidates, and historical and current dengue vaccine approaches. PMID:24373316

  13. DENGUE VIRAL INFECTIONS

    PubMed Central

    Gurugama, Padmalal; Garg, Pankaj; Perera, Jennifer; Wijewickrama, Ananda; Seneviratne, Suranjith L

    2010-01-01

    Dengue viral infections are one of the most important mosquito-borne diseases in the world. Presently dengue is endemic in 112 countries in the world. It has been estimated that almost 100 million cases of dengue fever and half a million cases of dengue hemorrhagic fever (DHF) occur worldwide. An increasing proportion of DHF is in children less than 15 years of age, especially in South East and South Asia. The unique structure of the dengue virus and the pathophysiologic responses of the host, different serotypes, and favorable conditions for vector breeding have led to the virulence and spread of the infections. The manifestations of dengue infections are protean from being asymptomatic to undifferentiated fever, severe dengue infections, and unusual complications. Early recognition and prompt initiation of appropriate supportive treatment are often delayed resulting in unnecessarily high morbidity and mortality. Attempts are underway for the development of a vaccine for preventing the burden of this neglected disease. This review outlines the epidemiology, clinical features, pathophysiologic mechanisms, management, and control of dengue infections. PMID:20418983

  14. Post dengue neurological complication.

    PubMed

    Hasliza, A H; Tohid, H; Loh, K Y; Santhi, P

    2015-01-01

    Dengue infection is highly endemic in many tropical countries including Malaysia. However, neurological complications arising from dengue infection is not common; Gullain-Barre syndrome (GBS) is one of these infrequent complications. In this paper, we have reported a case in which a 39-year-old woman presented with a neurological complication of dengue infection without typical symptoms and signs of dengue fever. She had a history of acute gastroenteritis (AGE) followed by an upper respiratory tract infection (URTI) weeks prior to her presentation rendering GBS secondary to the post viral URTI and AGE as the most likely diagnosis. Presence of thrombocytopenia was the only clue for dengue in this case. PMID:27099661

  15. Dengue: a continuing global threat

    PubMed Central

    Guzman, Maria G.; Halstead, Scott B.; Artsob, Harvey; Buchy, Philippe; Farrar, Jeremy; Gubler, Duane J.; Hunsperger, Elizabeth; Kroeger, Axel; Margolis, Harold S.; Martínez, Eric; Nathan, Michael B.; Pelegrino, Jose Luis; Simmons, Cameron; Yoksan, Sutee; Peeling, Rosanna W.

    2014-01-01

    Dengue fever and dengue haemorrhagic fever are important arthropod-borne viral diseases. Each year, there are ~50 million dengue infections and ~500,000 individuals are hospitalized with dengue haemorrhagic fever, mainly in Southeast Asia, the Pacific and the Americas. Illness is produced by any of the four dengue virus serotypes. A global strategy aimed at increasing the capacity for surveillance and outbreak response, changing behaviours and reducing the disease burden using integrated vector management in conjunction with early and accurate diagnosis has been advocated. Antiviral drugs and vaccines that are currently under development could also make an important contribution to dengue control in the future. PMID:21079655

  16. Rhombencephalitis associated with Dengue fever.

    PubMed

    Verma, Rajesh; Bharti, Kavita; Mehta, Mannan; Bansod, Amrit

    2016-05-01

    Dengue infection is gradually disseminating throughout the world in alarming proportions. It is a arbovirus infection,transmitted by aedes mosquitoes. It is a multi-systemic disorder associated with varied neurological complications. There is increased trend of development of neurological complications in dengue fever. The neurological complications arising due to dengue infection can be categorized into central and neuromuscular complications. The central nervous system disorders reported with dengue fever are encephalopathy,encephalitis and myelitis.Here we report a case of rhombencephalitis associated with dengue fever. The literature does not mention rhombencephalitis occurring with dengue illness. PMID:27015434

  17. Controversies in dengue pathogenesis.

    PubMed

    Halstead, Scott B

    2012-05-01

    Research into the pathogenesis of dengue fever has exploded over the last half-century, with issues that were considered simple becoming more complex as additional data are found. This has led to the development of a number of controversies that are being studied across the globe and debated in the literature. In this paper, the following six controversies are analysed and, where possible, resolved: the 1997 World Health Organization (WHO) case definition of dengue haemorrhagic fever (DHF) is not useful; DHF is not significantly associated with secondary dengue infection; DHF results from infection with a 'virulent' dengue virus; DHF is owing to abnormal T-cell responses; DHF results from auto-immune responses; and DHF results from direct infection of endothelial cells. PMID:22668442

  18. Dengue hemorrhagic fever

    MedlinePlus

    ... a severe, potentially deadly infection spread by some mosquitos. Causes Four different dengue viruses are known to ... occurs when a person is bitten by a mosquito that is infected with the virus. The mosquito ...

  19. Dengue Fever Testing

    MedlinePlus

    ... Dengue Virus by PCR Related tests: Arbovirus Testing , West Nile Virus Testing , Zika Virus Testing , Complete Blood Count , Electrolytes ... person is infected with another arbovirus such as West Nile virus . A health practitioner will consider a person's test ...

  20. Ecology and control of dengue vector mosquitoes in Taiwan.

    PubMed

    Chen, Y R; Hwang, J S; Guo, Y J

    1994-12-01

    Due to rapid urbanization, industrialization and social changes in recent years, the use of packing materials and tires has dramatically increased in the Taiwan area. What is more is that some parts of southern Taiwan are short of water resources and water preservation with huge containers becomes part of custom in those areas. Storage water containers, waste vessels and tires are good habitats for Aedes. Meanwhile, some persons traveling to dengue endemic countries bring the dengue disease back to Taiwan. Surveys taken since 1988 show that dengue occurs mainly in the urban and coastal areas where Aedes aegypti is prevalent. This species is the most important, if not the only, vector of dengue in Taiwan. It appears that the types of Aedes breeding have changed quickly. In dengue fever epidemic areas, the most popular breeding sites are ornamental containers (38.8%), storage water containers (30.1%), discarded containers (25.4%), receptacles (3.3%) and water collection in the basement (2.2%). In dengue fever epidemic areas, those building basements, huge water containers, waste vessels and waste tires in open fields are most difficult to clean up and manage and become the most popular Aedes habitats. We established a waste recycling system and promoted a breeding site reduction campaign for waste management, including the application of Temephos in containers to kill larvae. For the drinking water management, fish were released in water containers to prevent larval breeding. It should be mentioned that with the integrated pest control and regular inspections of Aedes larvae in Taiwan the density figures 1, 2-5, and 6 or above for Aedes aegypti were 38.7%, 42.9%, and 18.4%, respectively, in 1988, and in 1993 were 90.8%, 9.2% and 0%. The incidence of dengue fever cases has 98% decreased since 1988. In 1990 and 1993, there was no indigenous cases. We have concluded that integrated pest control is the best and most effective method for dengue fever control, including

  1. Enhancing knowledge and awareness of dengue during a prospective study of dengue fever.

    PubMed

    Beckett, Charmagne G; Kosasih, Herman; Tan, Ratna; Widjaja, Susana; Listianingsih, Erlin; Ma'roef, Chairin; Wuryadi, Suharyono; Alisjahbana, Bachti; Rudiman, Irani; McArdle, James L; Porter, Kevin R

    2004-09-01

    In 1992, the Indonesian CDC implemented strategies to control and prevent dengue fever (DF) by including community involvement to reduce larva breeding sites and a mass health education program. To contribute to this effort, we incorporated an educational component into a prospective study of DF conducted at two textile factories in Bandung. This education provided: a lecture on the signs and symptoms of dengue and ways to prevent the disease, posters in the health clinic at each factory and handouts given to each volunteer with an explanation of symptoms. Upon enrollment, each participant completed a questionnaire to gather demographic information. Additionally they were given a brief (non-standardized) test (PRE-test) of their dengue knowledge, which was verbally administered by the study physicians. Five questions (15 point system) were designed to assess the participant's ability to recognize and describe aspects of dengue in lay terms. The subject material included: the symptoms of acute DF, transmission of dengue virus, and basic steps for disease prevention. The same questionnaire was re-administered 18 months later (POST-test), and the results were compared. A total of 2,340 participants completed both the PRE- and POST-tests; there were 1,373 males and 967 females, median age 36 years (range 18-59). Only 0.3% of participants scored EXCELLENT (15-14 points) on the PRE-test whereas 8.4% scored EXCELLENT on the POST-test. Fewer participants scored VERY BAD (2-0 points) on the POST-test compared to the PRE-test (1.4% vs 4.0%). The average raw scores for the PRE- and POST-tests were 7.8 and 10.1, respectively. Improvement of individual scores correlated highly with educational level. No significant correlation was identified for gender, age, factory location or a diagnosis of dengue during the study. These findings demonstrate that our prospective study enhanced knowledge and awareness of dengue in the volunteers. PMID:15689076

  2. Dengue disease outbreak detection.

    PubMed

    Dayama, Pankaj; Sampath, Kameshwaran

    2014-01-01

    Early detection of outbreak of a disease may help in timely and effective public health interventions. Our motivation for this work is to assist EHD planning officer to analyze the incidence data and based on it declare whether there is an outbreak or not. In this paper, we develop ensemble of multiple techniques for detecting dengue disease outbreak. These techniques are applied to dengue incidence data from Singapore and results are summarized. PMID:25160360

  3. Insecticide susceptibility of the dengue vector, Aedes aegypti (L.) in Metropolitan Bangkok.

    PubMed

    Komalamisra, Narumon; Srisawat, Raweewan; Phanbhuwong, Theerawit; Oatwaree, Sompis

    2011-07-01

    Mosquito larvae were collected from the houses of dengue infected patients in Bangkok, Thailand from 55 sites (36 out of the 50 districts of Metropolitan Bangkok). Aedes aegypti larvae were tested against temephos using WHO bioassay techniques. Adult mosquitoes were tested for susceptibility to permethrin, deltamethrin, cyfluthrin, malathion and DDT using WHO diagnostic doses. Most of the larvae tested were susceptible to temephos. Only few specimens were resistant to temephos. Most adult mosquitoes were highly susceptible to malathion. Deltamethrin resistance was seen in 6 districts of Bangkok. Variable levels of susceptibility were seen with cyfluthrin. Most of the specimens showed resistance to permethrin and all specimens were resistant to DDT. PMID:22299463

  4. Dengue 3 Epidemic, Havana, 2001

    PubMed Central

    Peláez, Otto; Kourí, Gustavo; Pérez, Raúl; San Martín, José L.; Vázquez, Susana; Rosario, Delfina; Mora, Regla; Quintana, Ibrahim; Bisset, Juan; Cancio, Reynel; Masa, Ana M; Castro, Osvaldo; González, Daniel; Avila, Luis C.; Rodríguez, Rosmari; Alvarez, Mayling; Pelegrino, Jose L.; Bernardo, Lídice; Prado, Irina

    2004-01-01

    In June 2001, dengue transmission was detected in Havana, Cuba; 12,889 cases were reported. Dengue 3, the etiologic agent of the epidemic, caused the dengue hemorrhagic fever only in adults, with 78 cases and 3 deaths. After intensive vector control efforts, no new cases have been detected. PMID:15200868

  5. Chlorophyll derivatives can be an efficient weapon in the fight against dengue.

    PubMed

    Azizullah, Azizullah; Rehman, Zia Ur; Ali, Imran; Murad, Waheed; Muhammad, Noor; Ullah, Waheed; Häder, Donat-Peter

    2014-12-01

    Dengue, a mosquito-borne viral infection, is one of the major public health concerns in the tropical and subtropical regions of the world. Approximately, 2.5 billion people across the world are at risk from dengue and 50 to 100 million new infections of dengue occur annually. There is yet no vaccine or medicine available against dengue, and treatment remains only supportive. Targeting its vector by a combination of biological and chemical approaches and management of breeding sites are currently the only existing approaches to control or eliminate dengue. Chlorophyll derivatives like chlorophyllin and pheophorbide have been reported as effective natural photosensitizers against larvae of several insects including flies. Chlorophyll derivatives were also reported effective against larval stages of freshwater snails as well as against certain parasites of fish. This article briefly discusses the possible application of chlorophyll derivatives in controlling dengue vectors and hence the disease itself. Chlorophyll derivatives can prove to be a good contributor in an integrated approach against dengue. PMID:25316581

  6. Preventing dengue through mobile phones: evidence from a field experiment in Peru.

    PubMed

    Dammert, Ana C; Galdo, Jose C; Galdo, Virgilio

    2014-05-01

    Dengue is the most rapidly spreading mosquito-borne viral disease in the world (WHO, 2009). During the last two decades, the dramatic rise in the number of dengue infections has been particularly evident in Latin American and the Caribbean countries. This paper examines the experimental evidence of the effectiveness of mobile phone technology in improving households' health preventive behavior in dengue-endemic areas. The main results suggest that repeated exposure to health information encourages households' uptake of preventive measures against dengue. As a result, the Breteau Index in treatment households, an objective measure of dengue risk transmission, is 0.10 standard deviations below the mean of the control group, which shows a reduction in the number of containers per household that test positive for dengue larvae. The estimates also show marginally significant effects of the intervention on self-reported dengue symptoms. Moreover, we use a multiple treatment framework that randomly assigns households to one of the four treatment groups in order to analyze the impacts of framing on health behavior. Different variants emphasized information on monetary and non-monetary benefits and costs. The main results show no statistical differences among treatment groups. PMID:24681813

  7. Dengue--how best to classify it.

    PubMed

    Srikiatkhachorn, Anon; Rothman, Alan L; Gibbons, Robert V; Sittisombut, Nopporn; Malasit, Prida; Ennis, Francis A; Nimmannitya, Suchitra; Kalayanarooj, Siripen

    2011-09-01

    Dengue has emerged as a major public health problem worldwide. Dengue virus infection causes a wide range of clinical manifestations. Since the 1970s, clinical dengue has been classified according to the World Health Organization guideline as dengue fever and dengue hemorrhagic fever. The classification has been criticized with regard to its usefulness and its applicability. In 2009, the World Health Organization issued a new guideline that classifies clinical dengue as dengue and severe dengue. The 2009 classification differs significantly from the previous classification in both conceptual and practical levels. The impacts of the new classification on clinical practice, dengue research, and public health policy are discussed. PMID:21832264

  8. Dengue virus-infected Aedes aegypti in the home environment.

    PubMed

    Garcia-Rejon, Julian; Loroño-Pino, Maria Alba; Farfan-Ale, Jose Arturo; Flores-Flores, Luis; Del Pilar Rosado-Paredes, Elsy; Rivero-Cardenas, Nubia; Najera-Vazquez, Rosario; Gomez-Carro, Salvador; Lira-Zumbardo, Victor; Gonzalez-Martinez, Pedro; Lozano-Fuentes, Saul; Elizondo-Quiroga, Darwin; Beaty, Barry J; Eisen, Lars

    2008-12-01

    We determined abundance of Aedes aegypti mosquitoes and presence of dengue virus (DENV) in females collected from premises of laboratory-confirmed dengue patients over a 12-month period (March 2007 to February 2008) in Merida, Mexico. Backpack aspiration from 880 premises produced 1,836 females and 1,292 males indoors (predominantly from bedrooms) and 102 females and 108 males from patios/backyards. The mean weekly indoor catch rate per home peaked at 7.8 females in late August. Outdoor abundances of larvae or pupae were not predictive of female abundance inside the home. DENV-infected Ae. aegypti females were recovered from 34 premises. Collection of DENV-infected females from homes of dengue patients up to 27 days after the onset of symptoms (median, 14 days) shows the usefulness of indoor insecticide application in homes of suspected dengue patients to prevent their homes from becoming sources for dispersal of DENV by persons visiting and being bitten by infected mosquitoes. PMID:19052309

  9. DENGUE FEVER AND DENGUE HEMORRHAGIC FEVER IN ADULTS.

    PubMed

    Tantawichien, Terapong

    2015-01-01

    Dengue fever and dengue hemorrhagic fever are re-emerging diseases that are endemic in the Tropics. The global prevalence of dengue cases has increased in South-East Asia, Africa, the Western Pacific, and the Americas. The increasingly widespread distribution and the rising incidence of dengue virus infections are related to increased distribution of Aedes aegypti, an increasingly urban population, and increasing air travel. Several Southeast Asian countries show that the age of the reported dengue cases has increased from 5-9 years, to older children and young adults. Dengue infection in adolescents and adults has also been recognized as a potential hazard to international travelers returning from endemic areas, especially SoutheastAsia. Dengue is one disease entity with different clinical presentations; often with unpredictable clinical evolutions and outcomes. Bleeding manifestations in adult patients, including petechiae and menorrhagia were also frequently found; however, massive hematemesis may occur in adult patients because of peptic ulcer disease and may not be associated with profound shock as previously reported in children. Although shock and plasma leakage seem to be more prevalent as age decreases, the frequency of internal hemorrhage rises as age increases. Increase in liver enzymes found in both children and adults indicated liver involvement during dengue infections. Pre-existing liver diseases in adults such as chronic hepatitis, alcoholic cirrhosis, and hemoglobinopathies may aggravate the liver impairment in dengue infection. Fulminant hepatitis is a rare but well described problem in adult patients with dengue infection. Currently, no specific therapeutic agent exists for dengue. The early recognition of dengue infection, bleeding tendency, and signs of circulatory collapse would reduce mortality rates in adult patients with dengue infection. PMID:26506734

  10. [Maculopathy and dengue fever].

    PubMed

    Jellab, B; Fardeau, C; Lehoang, P

    2013-01-01

    The authors report a case of a 20 year old female who presented a bilateral decrease in vision. Detailed history revealed that 15 days before the onset of symptoms, the patient presented a dengue fever during her stay in Martinique. On initial examination, the fundus exam revealed a bilateral loss of foveal reflection. The optical coherence tomography demonstrated the macular edema and the dengue serology was postive. The patient received an interferon2a-based therapy. The macular edema disappeared and we noticed a partial but fast improvement of visual acuity 12 days after the treatment initiation. PMID:24923080

  11. Dengue Serosurvey in Sint Eustatius

    PubMed Central

    Leslie, Teresa; Martin, Nicholas J.; Jack-Roosberg, Carol; Odongo, George; Beausoleil, Edwin; Tuck, Jennifer; Raviprakash, Kanakatte; Kochel, Tadeusz J.

    2014-01-01

    Four distinct serotypes of dengue viruses (DENV) are the cause of re-emerging dengue fever (DF) and dengue hemorrhagic fever (DHF). Dengue circulation in the Caribbean has gone from none or single serotype to multiple serotypes co-circulating with reports of continuing cycles of progressively more severe disease in the region. Few studies have investigated dengue on Sint Eustatius. Blood samples were collected to determine the prevalence of antibodies against dengue in the Sint Eustatius population. Greater than 90% of the serum samples (184 of 204) were positive for anti-flavivirus antibodies by enzyme linked immunosorbance assay (ELISA). Plaque reduction neutralization test (PRNT), specific for dengue viruses, showed that 171 of these 184 flavivirus antibody positive sera had a neutralization titer against one or more DENV serotypes. A majority of the sera (62%) had neutralizing antibody to all four dengue serotypes. Only 26 PRNT positive sera (15%) had monotypic dengue virus neutralizing antibody, most of which (20 of 26) were against DENV2. Evidence of infection with all four serotypes was observed across all age groups except in the youngest age group (10–19 years) which contained only DENV2 positive individuals. In a multiple logistic regression model, only the length of residence on the island was a predictor of a positive dengue PRNT50 result. To our knowledge this is the first dengue serosurveillance study conducted on Sint Eustatius since the 1970s. The lack of antibodies to the DEN1, 3, and 4 in the samples collected from participants under 20 years of age suggests that only DEN2 has circulated on island since the early 1990s. The high prevalence of antibodies against dengue (83.8%) and the observation that the length of time on the island was the strongest predictor of infection suggests dengue is endemic on Sint Eustatius and a public health concern that warrants further investigation. PMID:24914538

  12. Fighting arboviral diseases: low toxicity on mammalian cells, dengue growth inhibition (in vitro), and mosquitocidal activity of Centroceras clavulatum-synthesized silver nanoparticles.

    PubMed

    Murugan, Kadarkarai; Aruna, Palanimuthu; Panneerselvam, Chellasamy; Madhiyazhagan, Pari; Paulpandi, Manickam; Subramaniam, Jayapal; Rajaganesh, Rajapandian; Wei, Hui; Alsalhi, Mohamad Saleh; Devanesan, Sandhanasamy; Nicoletti, Marcello; Syuhei, Ban; Canale, Angelo; Benelli, Giovanni

    2016-02-01

    Dengue is a mosquito-borne viral disease that has rapidly spread in all regions of the world in recent years. Female mosquitoes, mainly Aedes aegypti, transmit dengue. Approximately 3,900 million people, in 128 countries, are at risk of dengue infection. Recently, a focus has been provided on the potential of green-synthesized nanoparticles as inhibitors of the production of dengue viral envelope (E) protein in Vero cells and downregulators of the expression of dengue viral E gene. Algae are an outstanding reservoir of novel compounds, which may help in the fight against mosquito-borne diseases. In this research, silver nanoparticles (AgNP) were rapidly synthesized using a cheap extract of the alga Centroceras clavulatum. AgNP were characterized by UV–vis spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). In mosquitocidal assays, LC50 values of C. clavulatum extract against A. aegypti larvae and pupae were 269.361 ppm (larva I), 309.698 ppm (larva II), 348.325 ppm (larva III), 387.637 ppm (larva IV), and 446.262 ppm (pupa). C. clavulatum extract also exhibited moderate antioxidant activity, both in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) radical scavenging assays. LC50 values of C. clavulatum-synthesized AgNP were 21.460 ppm (larva I), 23.579 ppm (larva II), 25.912 ppm (larva III), 29.155 ppm (larva IV), and 33.877 ppm (pupa). Furthermore, C. clavulatum-synthesized AgNP inhibited dengue (serotype dengue virus type-2 (DEN-2)) viral replication in Vero cells. Notably, 50 μg/ml of green-synthesized AgNP showed no cytotoxicity on Vero cells while reduced DEN-2 viral growth of more than 80%; 12.5 μg/ml inhibited viral growth of more than 50%. Cellular internalization assays highlighted that untreated infected cells showed high intensity of fluorescence emission, which denotes high level of viral internalization. Conversely

  13. Dengue and dengue hemorrhagic fever, Brazil, 1981-2002.

    PubMed

    Siqueira, João Bosco; Martelli, Celina Maria Turchi; Coelho, Giovanini Evelim; Simplicio, Ana Cristina da Rocha; Hatch, Douglas L

    2005-01-01

    In the last 5 years, Brazil has accounted for approximately 70% of reported dengue fever cases in the Americas. We analyzed trends of dengue and dengue hemorrhagic fever (DHF) from the early 1980s to 2002 by using surveillance data from the Brazilian Ministry of Health. Two distinct epidemiologic patterns for dengue were observed: localized epidemics (1986-1993), and endemic and epidemic virus circulation countrywide (1994-2002). Currently, serotypes 1, 2, and 3 cocirculate in 22 of 27 states. Dengue and DHF affected mainly adults; however, an increase in occurrence of DHF among children has been recently detected in northern Brazil, which suggests a shift in the occurrence of severe disease to younger age groups. In 2002, hospitalizations increased, which points out the change in disease severity compared to that seen in the 1990s. We describe the epidemiology of dengue in Brazil, characterizing the changing patterns of it and DHF during the last 20 years. PMID:15705322

  14. Introducing dengue vaccine: Implications for diagnosis in dengue vaccinated subjects.

    PubMed

    Alagarasu, Kalichamy

    2016-05-27

    Diagnosis of dengue virus infections is complicated by preference for different diagnostic tests in different post onset days of illness and the presence of multiple serotypes leading to secondary and tertiary infections. The sensitivity of the most commonly employed diagnostic assays such as anti dengue IgM capture (MAC) ELISA and non structural protein (NS) 1 capture ELISA are lower in secondary and subsequent infections. Introduction of dengue vaccine in endemic regions will affect the way how dengue is diagnosed in vaccinated subjects. This viewpoint article discusses implications of introduction of dengue vaccine on the diagnosis of dengue infections in vaccinated subjects and the strategies that are needed to tackle the issue. PMID:27142330

  15. A Dengue Vaccine.

    PubMed

    Durbin, Anna P

    2016-06-30

    Denvaxia is the first licensed vaccine for the prevention of dengue. It is a live vaccine developed using recombinant DNA technology. The vaccine is given as three doses over the course of a year and has the potential to prevent hundreds of thousands of hospitalizations each year. PMID:27368091

  16. [Dengue, Zika and Chikungunya].

    PubMed

    Kantor, Isabel N

    2016-01-01

    Arboviruses are transmitted by arthropods, including those responsible for the current pandemic: alphavirus (Chikungunya) and flaviviruses (dengue and Zika). Its importance increased in the Americas over the past 20 years. The main vectors are Aedes aegypti and A. albopictus. Dengue infection provides long lasting immunity against the specific serotype and temporary to the other three. Subsequent infection by another serotype determines more serious disease. There is a registered vaccine for dengue, Dengvaxia (Sanofi Pasteur). Other two (Butantan and Takeda) are in Phase III in 2016. Zika infection is usually asymptomatic or occurs with rash, conjunctivitis and not very high fever. There is no vaccine or specific treatment. It can be transmitted by parental, sexual and via blood transfusion. It has been associated with microcephaly. Chikungunya causes prolonged joint pain and persistent immune response. Two candidate vaccines are in Phase II. Dengue direct diagnosis is performed by virus isolation, RT-PCR and ELISA for NS1 antigen detection; indirect methods are ELISA-IgM (cross-reacting with other flavivirus), MAC-ELISA, and plaque neutralization. Zika is diagnosed by RT-PCR and virus isolation. Serological diagnosis cross-reacts with other flavivirus. For CHIKV culture, RT-PCR, MAC-ELISA and plaque neutralization are used. Against Aedes organophosphate larvicides (temephos), organophosphorus insecticides (malathion and fenitrothion) and pyrethroids (permethrin and deltamethrin) are usually employed. Resistance has been described to all these products. Vegetable derivatives are less expensive and biodegradable, including citronella oil, which microencapsulated can be preserved from evaporation. PMID:26942903

  17. Dengue in Florida (USA)

    PubMed Central

    Rey, Jorge R.

    2014-01-01

    Florida (USA), particularly the southern portion of the State, is in a precarious situation concerning arboviral diseases. The geographic location, climate, lifestyle, and the volume of travel and commerce are all conducive to arbovirus transmission. During the last decades, imported dengue cases have been regularly recorded in Florida, and the recent re-emergence of dengue as a major public health concern in the Americas has been accompanied by a steady increase in the number of imported cases. In 2009, there were 28 cases of locally transmitted dengue in Key West, and in 2010, 65 cases were reported. Local transmission was also reported in Martin County in 2013 (29 cases), and isolated locally transmitted cases were also reported from other counties in the last five years. Dengue control and prevention in the future will require close cooperation between mosquito control and public health agencies, citizens, community and government agencies, and medical professionals to reduce populations of the vectors and to condition citizens and visitors to take personal protection measures that minimize bites by infected mosquitoes. PMID:26462955

  18. Dengue: Lessons of an Outbreak

    PubMed Central

    Siddiqui, Oves; Abhishek, Kumar S.

    2016-01-01

    Introduction Since 1967 there have been many outbreaks of dengue in Delhi. In the year 2015 Delhi has suffered it’s one of the worst dengue outbreaks, with more than 15000 dengue confirmed cases and the highest number of deaths (60) in recent years. Aim To determine the status of Dengue cases as compared to previous six years, the ratio of primary and secondary dengue cases and to review the effectiveness of the one test strategy (either NS1 antigen or IgM antibody) for the confirmation of Dengue. Materials and Methods A cross-sectional study was performed in the year 2015. A total of 7177 serum samples were tested for the confirmation of suspected cases of dengue at our institute. We performed dengue NS1 antigen and dengue IgM antibody ELISA tests for the confirmation of dengue cases in acute and convalescent fever cases respectively. Hundred random samples negative for NS1 antigen were tested for IgM antibody and 100 random samples negative for IgM antibody were tested for NS1 antigen. For determination of ratio of primary and secondary dengue cases, IgG Avidity ELISA was performed on random 76 dengue positive samples. Results Out of 7177 samples tested, 2358 were positive either by NS1 antigen or for IgM antibody from January to December. Percentage positivity rates for IgM antibody detection and NS1 antigen detection tests were 24.8% (626) and 37.1% (1732) respectively. Out of 100 NS1 negative samples 8 were positive for IgM antibody and out of 100 IgM negative samples 6 were positive for NS1 antigen. Among the 76 samples tested for dengue IgG Avidity ELISA 52 (68.4%) were found to be of secondary dengue. Conclusion Number of dengue cases is constantly rising in Delhi since 2011 and 2014. IgM antibody detection and NS1 antigen detection both the tests should be performed for each patient. Due to the increased prevalence of past infection of dengue, percentage of secondary dengue cases is also increasing in Delhi.

  19. Clustering, climate and dengue transmission.

    PubMed

    Junxiong, Pang; Yee-Sin, Leo

    2015-06-01

    Dengue is currently the most rapidly spreading vector-borne disease, with an increasing burden over recent decades. Currently, neither a licensed vaccine nor an effective anti-viral therapy is available, and treatment largely remains supportive. Current vector control strategies to prevent and reduce dengue transmission are neither efficient nor sustainable as long-term interventions. Increased globalization and climate change have been reported to influence dengue transmission. In this article, we reviewed the non-climatic and climatic risk factors which facilitate dengue transmission. Sustainable and effective interventions to reduce the increasing threat from dengue would require the integration of these risk factors into current and future prevention strategies, including dengue vaccination, as well as the continuous support and commitment from the political and environmental stakeholders. PMID:25872683

  20. Frequency and Clinical Features of Dengue Infection in a Schoolchildren Cohort from Medellin, Colombia

    PubMed Central

    Restrepo, Berta Nelly; Piedrahita, Leidy Diana; Agudelo, Ivony Yireth; Parra-Henao, Gabriel; Osorio, Jorge E.

    2012-01-01

    To determine the incidence of dengue infection, we established active surveillance of febrile episodes in a cohort of schoolchildren from three schools in Medellin, Colombia. We followed a cohort of 2,379 schoolchildren in 2010 and followed 1,840 of these children the following year. During the follow-up time, 264 schoolchildren displayed 297 febrile episodes; of these, 23 episodes (7.7%) were caused by acute dengue infection. All four dengue serotypes were found, and all of the cases were mild. The most common symptoms in the dengue cases compared with those in other febrile illness were asthenia (96% versus 87%), anorexia (78% versus 57%), rhinorrhea (65.2% versus 58%), abdominal pain (56.5% versus 47.8%), arthralgia (43% versus 33%), and positive tourniquet test (13% versus 3%). This difference was not statistically significant. Pulse was elevated, and systolic arterial pressure was lower in dengue cases compared with other febrile illness (P < 0.05). Mosquito indexes were determined in 8 children's houses and in the schools. Aedes aegypti adults were found in both households and in schools, whereas Aedes aegypti larvae were found only in schools. These results showed an elevated dengue frequency in children, with symptoms similar to those of other febrile illness and transmission risk in households and schools. PMID:23304167

  1. Reclassification of Paenibacillus larvae subsp. pulvifaciens and Paenibacillus larvae subsp. larvae as Paenibacillus larvae without subspecies differentiation.

    PubMed

    Genersch, Elke; Forsgren, Eva; Pentikäinen, Jaana; Ashiralieva, Ainura; Rauch, Sandra; Kilwinski, Jochen; Fries, Ingemar

    2006-03-01

    A polyphasic taxonomic study of the two subspecies of Paenibacillus larvae, Paenibacillus larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens, supported the reclassification of the subspecies into one species, Paenibacillus larvae, without subspecies separation. Our conclusions are based on the analysis of six reference strains of P. larvae subsp. pulvifaciens and three reference strains and 44 field isolates of P. larvae. subsp. larvae. The latter originated from brood or honey of clinically diseased honey bee colonies or from honey of both clinically diseased and asymptomatic colonies from Sweden, Finland and Germany. Colony and spore morphology, as well as the metabolism of mannitol and salicin, did not allow a clear identification of the two subspecies and SDS-PAGE of whole-cell proteins did not support the subspecies differentiation. For genomic fingerprinting, repetitive element-PCR fingerprinting using ERIC primers and PFGE of bacterial DNA were performed. The latter method is a high-resolution DNA fingerprinting method proven to be superior to most other methods for biochemical and molecular typing and has not previously been used to characterize P. larvae. ERIC-PCR identified four different genotypes, while PFGE revealed two main clusters. One cluster included most of the P. larvae subsp. larvae field isolates, as well as all P. larvae subsp. pulvifaciens reference strains. The other cluster comprised the pigmented variants of P. larvae subsp. larvae. 16S rRNA gene sequences were determined for some strains. Finally, exposure bioassays demonstrated that reference strains of P. larvae subsp. pulvifaciens were pathogenic for honey bee larvae, producing symptoms similar to reference strains of P. larvae subsp. larvae. In comparison with the type strain for P. larvae subsp. larvae, ATCC 9545T, the P. larvae subsp. pulvifaciens strains tested were even more virulent, since they showed a shorter LT100. An emended description of the species is given

  2. [Larva migrans cutanea].

    PubMed

    Nevoralová, Z

    2006-01-01

    A case of rare skin disease in Czech Republic caused by nematode larva is presented. The disease is most frequently caused by Ankylostoma brasiliensis and was imported from Brazil. It was successfully treated by peroral therapy with albendazol. PMID:16639935

  3. Baylisascaris larva migrans.

    PubMed

    Kazacos, Kevin R; Jelicks, Linda A; Tanowitz, Herbert B

    2013-01-01

    Baylisascaris procyonis is a roundworm of the raccoon found primarily in North America but also known to occur in other parts of the world including South America, Europe, and Japan. Migration of the larvae of this parasite is recognized as a cause of clinical neural larva migrans (NLM) in humans, primarily children. It is manifested as meningoencephalitis associated with marked eosinophilia of the cerebrospinal fluid and peripheral blood. Diagnosis is made by recovering and identifying larvae in or from the tissues, epidemiological history, serology, and imaging of the central nervous system. Treatment is with albendazole and steroids, although the prognosis is generally poor. This parasite can also cause ocular larva migrans (OLM) which usually presents as diffuse unilateral subacute neuroretinitis (DUSN). The ocular diagnosis can be made by visualizing the larva in the eye and by serology. Intraocular larvae can be destroyed by photocoagulation although albendazole and steroids may also be used. However, once visual disturbance is established the prognosis for improved vision is poor. Related Baylisascaris species occur in skunks, badgers, and certain other carnivores, although most cases of NLM are caused by B. procyonis. Baylisascaris procyonis has also been found in kinkajous in the USA and South America and may also occur in related procyonids (coatis, olingos, etc.). PMID:23829916

  4. Current progress in dengue vaccines

    PubMed Central

    2013-01-01

    Dengue is one of the most important emerging vector-borne viral diseases. There are four serotypes of dengue viruses (DENV), each of which is capable of causing self-limited dengue fever (DF) or even life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). The major clinical manifestations of severe DENV disease are vascular leakage, thrombocytopenia, and hemorrhage, yet the detailed mechanisms are not fully resolved. Besides the direct effects of the virus, immunopathological aspects are also involved in the development of dengue symptoms. Although no licensed dengue vaccine is yet available, several vaccine candidates are under development, including live attenuated virus vaccines, live chimeric virus vaccines, inactivated virus vaccines, and live recombinant, DNA and subunit vaccines. The live attenuated virus vaccines and live chimeric virus vaccines are undergoing clinical evaluation. The other vaccine candidates have been evaluated in preclinical animal models or are being prepared for clinical trials. For the safety and efficacy of dengue vaccines, the immunopathogenic complications such as antibody-mediated enhancement and autoimmunity of dengue disease need to be considered. PMID:23758699

  5. Dengue-associated neuromuscular complications.

    PubMed

    Garg, Ravindra Kumar; Malhotra, Hardeep Singh; Jain, Amita; Malhotra, Kiran Preet

    2015-01-01

    Dengue is associated with many neurological dysfunctions. Up to 4% of dengue patients may develop neuromuscular complications. Muscle involvement can manifest with myalgias, myositis, rhabdomyolysis and hypokalemic paralysis. Diffuse myalgia is the most characteristic neurological symptom of dengue fever. Dengue-associated myositis can be of varying severity ranging from self-limiting muscle involvement to severe dengue myositis. Dengue-associated hypokalemic paralysis often has a rapidly evolving course; benign nature; excellent response to potassium; and, often leads to diagnostic confusion with other dengue-associated neuromuscular disorders. Rhabdomyolysis is the most severe form of muscle involvement and may be life-threatening. Guillain-Barrι syndrome is another frequent neuromuscular dengue-associated complication. Dengue-associated Guillain-Barrι syndrome responds very well to intravenous immunoglobulins. Predominant spinal gray matter involvement has been reported in a patient presenting with areflexic paraparesis. Mononeuropathies often manifest with paralysis of the diaphragm due to phrenic nerve dysfunction. Brachial plexopathy, in the form of neuralgic amyotrophy, has been described much more frequently than lumbo-sacral plexopathy. Early recognition of these neuromuscular complications is needed for successful treatment and to prevent further disabilities. PMID:26238884

  6. Overview of current situation of dengue and dengue vector control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dengue is the most important arbovirus of humans in the world. It is caused by one of four closely related virus serotypes whose primary vector is Aedes aegypti and secondarily by Ae. albopictus. A global dengue pandemic began in Southeast Asia after World War II and has intensified during the las...

  7. Odonate Nymphs: Generalist Predators and Their Potential in the Management of Dengue Mosquito, Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    Akram, Waseem; Ali-Khan, Hafiz Azhar

    2016-01-01

    Background: Dengue is amongst the most serious mosquito-borne infectious disease with hot spots in tropical and subtropical parts of the world. Unfortunately, no licensed vaccine for the disease is currently available in medicine markets. The only option available is the management of dengue vector mosquito, Aedes aegypti (Diptera: Culicidae). Method: Predatory potential of five odonate nymphs namely Anax parthenope, Bradinopyga geminate, Ischnura forcipata, Rhinocypha quadrimaculata, and Orthetrum sabina were evaluated against the 4th instar larvae of the dengue vector mosquito, Aedes aegypti, under laboratory conditions. The consumption of the mosquito larvae was evaluated at three water volume levels viz., 1 liter, 2 liter and 3 liter. Results: The number of Ae. aegypti larvae consumed varied significantly among the five species, and at different levels of water volume (P< 0.01). However, the interaction between odonate nymphs and the water volumes was statistically non-significant (P> 0.05). Ischnura forcipata consumed the highest number of Ae. aegypti larvae (n=56) followed by A. parthenope (n=47) and B. geminate (n=46). The number of larvae consumed was decreased with increasing search area or water volume, and the highest predation was observed at 1-liter water volume. Conclusion: The odonate nymphs could be a good source of biological agents for the management of the mosquitoes at larval stages. PMID:27308283

  8. Costs of Three Wolbachia Infections on the Survival of Aedes aegypti Larvae under Starvation Conditions

    PubMed Central

    Ross, Perran A.; Endersby, Nancy M.; Hoffmann, Ary A.

    2016-01-01

    The mosquito Aedes aegypti, the principal vector of dengue virus, has recently been infected experimentally with Wolbachia: intracellular bacteria that possess potential as dengue biological control agents. Wolbachia depend on their hosts for nutrients they are unable to synthesize themselves. Consequently, competition between Wolbachia and their host for resources could reduce host fitness under the competitive conditions commonly experienced by larvae of Ae. aegypti in the field, hampering the invasion of Wolbachia into natural mosquito populations. We assess the survival and development of Ae. aegypti larvae under starvation conditions when infected with each of three experimentally-generated Wolbachia strains: wMel, wMelPop and wAlbB, and compare their fitness to wild-type uninfected larvae. We find that all three Wolbachia infections reduce the survival of larvae relative to those that are uninfected, and the severity of the effect is concordant with previously characterized fitness costs to other life stages. We also investigate the ability of larvae to recover from extended food deprivation and find no effect of Wolbachia on this trait. Aedes aegypti larvae of all infection types were able to resume their development after one month of no food, pupate rapidly, emerge at a large size, and exhibit complete cytoplasmic incompatibility and maternal transmission. A lowered ability of Wolbachia-infected larvae to survive under starvation conditions will increase the threshold infection frequency required for Wolbachia to establish in highly competitive natural Ae. aegypti populations and will also reduce the speed of invasion. This study also provides insights into survival strategies of larvae when developing in stressful environments. PMID:26745630

  9. Wolbachia versus dengue

    PubMed Central

    Bull, James J.; Turelli, Michael

    2013-01-01

    A novel form of biological control is being applied to the dengue virus. The agent is the maternally transmitted bacterium Wolbachia, naturally absent from the main dengue vector, the mosquito Aedes aegypti. Three Wolbachia-based control strategies have been proposed. One is suppression of mosquito populations by large-scale releases of males incompatible with native females; this intervention requires ongoing releases. The other interventions transform wild mosquito populations with Wolbachia that spread via the frequency-dependent fitness advantage of Wolbachia-infected females; those interventions potentially require just a single, local release for area-wide disease control. One of these latter strategies uses Wolbachia that shortens mosquito life, indirectly preventing viral maturation/transmission. The other strategy uses Wolbachia that block viral transmission. All interventions can be undermined by viral, bacterial or mosquito evolution; viral virulence in humans may also evolve. We examine existing theory, experiments and comparative evidence to motivate predictions about evolutionary outcomes. (i) The life-shortening strategy seems the most likely to be thwarted by evolution. (ii) Mosquito suppression has a reasonable chance of working locally, at least in the short term, but long-term success over large areas is challenging. (iii) Dengue blocking faces strong selection for viral resistance but may well persist indefinitely at some level. Virulence evolution is not mathematically predictable, but comparative data provide no precedent for Wolbachia increasing dengue virulence. On balance, our analysis suggests that the considerable possible benefits of these technologies outweigh the known negatives, but the actual risk is largely unknown. PMID:24481199

  10. Prospects for dengue vaccines for travelers

    PubMed Central

    2016-01-01

    Travel-acquired dengue cases have been increasing as the overall global dengue burden has expanded. In Korea, imported dengue cases have been reported since 2000 when it first became a notifiable disease. During the first four months of 2016, three times more dengue cases were reported in Korea than during the same period the previous year. A safe and efficacious vaccine for travelers would be beneficial to prevent dengue disease in individual travelers and potentially decrease the risk of virus spread to non-endemic areas. Here, we summarize the characteristics of dengue vaccines for travelers and review dengue vaccines currently licensed or in clinical development. PMID:27489798

  11. Prospects for dengue vaccines for travelers.

    PubMed

    Lim, Sl-Ki; Lee, Yong Seok; Namkung, Suk; Lim, Jacqueline K; Yoon, In-Kyu

    2016-07-01

    Travel-acquired dengue cases have been increasing as the overall global dengue burden has expanded. In Korea, imported dengue cases have been reported since 2000 when it first became a notifiable disease. During the first four months of 2016, three times more dengue cases were reported in Korea than during the same period the previous year. A safe and efficacious vaccine for travelers would be beneficial to prevent dengue disease in individual travelers and potentially decrease the risk of virus spread to non-endemic areas. Here, we summarize the characteristics of dengue vaccines for travelers and review dengue vaccines currently licensed or in clinical development. PMID:27489798

  12. Baylisascaris larva migrans

    USGS Publications Warehouse

    Kazacos, Kevin R.

    2016-01-01

    SummaryBaylisascaris procyonis, the common raccoon roundworm, is the most commonly recognized cause of clinical larva migrans (LM) in animals, a condition in which an immature parasitic worm or larva migrates in a host animal’s tissues, causing obvious disease. Infection with B. procyonis is best known as a cause of fatal or severe neurologic disease that results when the larvae invade the brain, the spinal cord, or both; this condition is known as neural larva migrans (NLM). Baylisascariasis is a zoonotic disease, that is, one that is transmissible from animals to humans. In humans, B. procyonis can cause damaging visceral (VLM), ocular (OLM), and neural larva migrans. Due to the ubiquity of infected raccoons around humans, there is considerable human exposure and risk of infection with this parasite. The remarkable disease-producing capability of B. procyonis in animals and humans is one of the most significant aspects of the biology of ascarids (large roundworms) to come to light in recent years. Infection with B. procyonis has important health implications for a wide variety of free-ranging and captive wildlife, zoo animals, domestic animals, as well as human beings, on both an individual and population level. This report, eighth in the series of U.S. Geological Survey Circulars on zoonotic diseases, will help us to better understand the routes of Baylisascaris procyonis infections and how best to adequately monitor this zoonotic disease.

  13. DGV: Dengue Genographic Viewer

    PubMed Central

    Yamashita, Akifumi; Sakamoto, Tetsuya; Sekizuka, Tsuyoshi; Kato, Kengo; Takasaki, Tomohiko; Kuroda, Makoto

    2016-01-01

    Dengue viruses (DENVs) and their vectors are widely distributed throughout the tropical and subtropical regions of the world. An autochthonous case of DENV was reported in Tokyo, Japan, in 2014, for the first time in 70 years. A comprehensive database of DENV sequences containing both serotype and genotype data and epidemiological data is crucial to trace DENV outbreak isolates and promptly respond to outbreaks. We constructed a DENV database containing the serotype, genotype, year and country/region of collection by collecting all publically available DENV sequence information from the National Center for Biotechnology Information (NCBI) and assigning genotype information. We also implemented the web service Dengue Genographic Viewer (DGV), which shows the geographical distribution of each DENV genotype in a user-specified time span. DGV also assigns the serotype and genotype to a user-specified sequence by performing a homology search against the curated DENV database, and shows its homologous sequences with the geographical position and year of collection. DGV also shows the distribution of DENV-infected entrants to Japan by plotting epidemiological data from the Infectious Agents Surveillance Report (IASR), Japan. This overview of the DENV genotype distribution may aid in planning for the control of DENV infections. DGV is freely available online at: (https://gph.niid.go.jp/geograph/dengue/content/genomemap). PMID:27375595

  14. Identification of Essential Containers for Aedes Larval Breeding to Control Dengue in Dhaka, Bangladesh

    PubMed Central

    Ferdousi, Farhana; Yoshimatsu, Shoji; Ma, Enbo; Sohel, Nazmul; Wagatsuma, Yukiko

    2015-01-01

    Dengue fever (DF), one of the most important emerging arboviral diseases, is transmitted through the bite of container breeding mosquitoes Aedes aegypti and Aedes albopictus. A household entomological survey was conducted in Dhaka from August through October 2000 to inspect water-holding containers in indoor, outdoor, and rooftop locations for Aedes larvae. The objective of this study was to determine mosquito productivity of each container type and to identify some risk factors of households infested with Aedes larvae. Of 9,222 households inspected, 1,306 (14.2%) were positive for Aedes larvae. Of 38,777 wet containers examined, 2,272 (5.8%) were infested with Aedes larvae. Containers used to hold water, such as earthen jars, tanks, and drums were the most common containers for larval breeding. Tires in outdoor and rooftop locations of the households were also important for larval breeding. Although present in abundance, buckets were of less importance. Factors such as independent household, presence of a water storage system in the house, and fully/partly shaded outdoors were found to be significantly associated with household infestation of Aedes larvae. Identification and subsequent elimination of the most productive containers in a given area may potentially reduce mosquito density to below a level at which dengue transmission may be halted. PMID:26865829

  15. Identification of Essential Containers for Aedes Larval Breeding to Control Dengue in Dhaka, Bangladesh.

    PubMed

    Ferdousi, Farhana; Yoshimatsu, Shoji; Ma, Enbo; Sohel, Nazmul; Wagatsuma, Yukiko

    2015-12-01

    Dengue fever (DF), one of the most important emerging arboviral diseases, is transmitted through the bite of container breeding mosquitoes Aedes aegypti and Aedes albopictus. A household entomological survey was conducted in Dhaka from August through October 2000 to inspect water-holding containers in indoor, outdoor, and rooftop locations for Aedes larvae. The objective of this study was to determine mosquito productivity of each container type and to identify some risk factors of households infested with Aedes larvae. Of 9,222 households inspected, 1,306 (14.2%) were positive for Aedes larvae. Of 38,777 wet containers examined, 2,272 (5.8%) were infested with Aedes larvae. Containers used to hold water, such as earthen jars, tanks, and drums were the most common containers for larval breeding. Tires in outdoor and rooftop locations of the households were also important for larval breeding. Although present in abundance, buckets were of less importance. Factors such as independent household, presence of a water storage system in the house, and fully/partly shaded outdoors were found to be significantly associated with household infestation of Aedes larvae. Identification and subsequent elimination of the most productive containers in a given area may potentially reduce mosquito density to below a level at which dengue transmission may be halted. PMID:26865829

  16. Hepatic visceral larva migrans

    PubMed Central

    Rohilla, Seema; Jain, Nitin; Yadav, Rohtas; Dhaulakhandi, Dhara Ballabh

    2013-01-01

    Visceral larva migrans (VLM) is a systemic manifestation of migration of second stage larvae of nematodes through the tissue of human viscera. It is not uncommon but is underdiagnosed in developing countries. The liver is the most common organ to be involved due to its portal venous blood supply. The imaging findings are subtle and differentiation from hepatocellular carcinoma (HCC), metastases, cystic mesenchymal hamartoma and granulomatous diseases is difficult. This case report highlights the imaging features of hepatic lesions of VLM along with clinical and laboratory data which help in clinching the diagnosis. PMID:23853189

  17. Mortality Predictors in Patients with Severe Dengue in the State of Amazonas, Brazil

    PubMed Central

    Pinto, Rosemary Costa; de Castro, Daniel Barros; de Albuquerque, Bernardino Cláudio; Sampaio, Vanderson de Souza; dos Passos, Ricardo Augusto; da Costa, Cristiano Fernandes; Sadahiro, Megumi; Braga, José Ueleres

    2016-01-01

    Dengue is a major public health problem in tropical and subtropical areas worldwide. There is a lack of information on the risk factors for death due to severe dengue fever in developing countries, including Brazil where the state of Amazonas is located. This knowledge is important for decision making and the implementation of effective measures for patient care. This study aimed to identify factors associated with death among patients with severe dengue, in Amazonas from 2001 to 2013. We conducted a retrospective cohort study based on secondary data from the epidemiological surveillance of dengue provided by the Fundação de Vigilância em Saúde do Amazonas, FVS (Health Surveillance Foundation) of the Secretaria de Saúde do Amazonas, SUSAM (Health Secretariat of the State of Amazonas). Data on dengue cases were obtained from the SINAN (Notifiable Diseases Information System) and SIM (Mortality Information System) databases. We selected cases of severe dengue with laboratory confirmation, including dengue-related deaths of residents in the state of Amazonas from January 1, 2001, to December 31, 2013. The explanatory variables analyzed were sex, age, level of education, spontaneous hemorrhagic manifestations, plasma extravasation and platelet count. Patients who died due to severe dengue had more hematuria, gastrointestinal bleeding, and thrombocytopenia than the survivors. Considering the simultaneous effects of demographic and clinical characteristics with a multiple logistic regression model, it was observed that the factors associated with death were age >55 years (odds ratio [OR] 4.98), gastrointestinal bleeding (OR 10.26), hematuria (OR 5.07), and thrombocytopenia (OR 2.55). Gastrointestinal bleeding was the clinical sign most strongly associated with death, followed by hematuria and age >55 years. The study results showed that the best predictor of death from severe dengue is based on the characteristic of age >55 years, together with the clinical signs of

  18. Mortality Predictors in Patients with Severe Dengue in the State of Amazonas, Brazil.

    PubMed

    Pinto, Rosemary Costa; Castro, Daniel Barros de; Albuquerque, Bernardino Cláudio de; Sampaio, Vanderson de Souza; Passos, Ricardo Augusto Dos; Costa, Cristiano Fernandes da; Sadahiro, Megumi; Braga, José Ueleres

    2016-01-01

    Dengue is a major public health problem in tropical and subtropical areas worldwide. There is a lack of information on the risk factors for death due to severe dengue fever in developing countries, including Brazil where the state of Amazonas is located. This knowledge is important for decision making and the implementation of effective measures for patient care. This study aimed to identify factors associated with death among patients with severe dengue, in Amazonas from 2001 to 2013. We conducted a retrospective cohort study based on secondary data from the epidemiological surveillance of dengue provided by the Fundação de Vigilância em Saúde do Amazonas, FVS (Health Surveillance Foundation) of the Secretaria de Saúde do Amazonas, SUSAM (Health Secretariat of the State of Amazonas). Data on dengue cases were obtained from the SINAN (Notifiable Diseases Information System) and SIM (Mortality Information System) databases. We selected cases of severe dengue with laboratory confirmation, including dengue-related deaths of residents in the state of Amazonas from January 1, 2001, to December 31, 2013. The explanatory variables analyzed were sex, age, level of education, spontaneous hemorrhagic manifestations, plasma extravasation and platelet count. Patients who died due to severe dengue had more hematuria, gastrointestinal bleeding, and thrombocytopenia than the survivors. Considering the simultaneous effects of demographic and clinical characteristics with a multiple logistic regression model, it was observed that the factors associated with death were age >55 years (odds ratio [OR] 4.98), gastrointestinal bleeding (OR 10.26), hematuria (OR 5.07), and thrombocytopenia (OR 2.55). Gastrointestinal bleeding was the clinical sign most strongly associated with death, followed by hematuria and age >55 years. The study results showed that the best predictor of death from severe dengue is based on the characteristic of age >55 years, together with the clinical signs of

  19. Dengue human infection models to advance dengue vaccine development.

    PubMed

    Larsen, Christian P; Whitehead, Stephen S; Durbin, Anna P

    2015-12-10

    Dengue viruses (DENV) currently infect approximately 400 million people each year causing millions to seek care and overwhelming the health care infrastructure in endemic areas. Vaccines to prevent dengue and therapeutics to treat dengue are not currently available. The efficacy of the most advanced candidate vaccine against symptomatic dengue in general and DENV-2 in particular was much lower than expected, despite the ability of the vaccine to induce neutralizing antibody against all four DENV serotypes. Because seroconversion to the DENV serotypes following vaccination was thought to be indicative of induced protection, these results have made it more difficult to assess which candidate vaccines should or should not be evaluated in large studies in endemic areas. A dengue human infection model (DHIM) could be extremely valuable to down-select candidate vaccines or therapeutics prior to engaging in efficacy trials in endemic areas. Two DHIM have been developed to assess the efficacy of live attenuated tetravalent (LATV) dengue vaccines. The first model, developed by the Laboratory of Infectious Diseases at the U. S. National Institutes of Health, utilizes a modified DENV-2 strain DEN2Δ30. This virus was derived from the DENV-2 Tonga/74 that caused only very mild clinical infection during the outbreak from which it was recovered. DEN2Δ30 induced viremia in 100%, rash in 80%, and neutropenia in 27% of the 30 subjects to whom it was given. The Walter Reed Army Institute of Research (WRAIR) is developing a DHIM the goal of which is to identify DENV that cause symptomatic dengue fever. WRAIR has evaluated seven viruses and has identified two that meet dengue fever criteria. Both of these models may be very useful in the evaluation and down-selection of candidate dengue vaccines and therapeutics. PMID:26424605

  20. Challenges encountered using standard vector control measures for dengue in Boa Vista, Brazil

    PubMed Central

    Valle, Denise

    2014-01-01

    Abstract Problem In 2010, dengue virus (DENV) serotype–4 was detected during a dengue outbreak in the Amazonian city of Boa Vista. At that time Brazil was already endemic for DENV-1, DENV-2 and DENV-3. This was the first time DENV-4 was observed in the country after it was initially detected and eliminated in 1981. Approach To hinder the spread of DENV-4 throughout Brazil, standard vector control measures were intensified. Vector control professionals visited 56 837 households in 22 out of 31 districts of Boa Vista, to eliminate mosquito-breeding sites. Water storage containers were treated with the larvicide diflubenzuron, and deltamethrin was sprayed for adult Aedes aegypti mosquitoes. Fifteen days later, a second larvae survey and additional deltamethrin applications were performed. Local setting In Brazil, dengue vector control is managed at all three government levels. Regular surveillance of Aedes aegypti is done four to six times a year to strengthen mosquito control activities in areas with high-vector density. Educational dengue control campaigns in communities are scarce, especially between outbreaks. Relevant changes In spite of extensive implementation of all standard control actions recommended by the Brazilian dengue control programme, only a slight decrease in mosquito density was detected. Lessons learnt There is a need to redesign all levels of dengue control. Public consultation and engagement, behaviour change and actions that go beyond technical impositions are required. Vector control programme managers need to reflect on what constitutes good practices and whether intermittent information campaigns are effective measures for dengue prevention and control. PMID:25378760

  1. Dengue and other flavivirus infections.

    PubMed

    Choumet, V; Desprès, Ph

    2015-08-01

    Flaviviruses are responsible for yellow fever, Zika fever and dengue, all of which are major human diseases found in tropical regions of the globe. They are zoonoses with a transmission cycle that involves primates as reservoirs and mosquitoes of the genus Aedes as vectors. The recent upsurge of urban epidemics of yellow fever, Zika fever and dengue has involved human-to-human transmission with mosquitoes as the vector. This paper is primarily concerned with dengue, which has become the pre-eminent arbovirosis in terms of public health. PMID:26601449

  2. Post-dengue encephalopathy and Parkinsonism.

    PubMed

    Fong, Choong Yi; Hlaing, Chaw Su; Tay, Chee Geap; Ong, Lai Choo

    2014-10-01

    Parkinsonism as a neurologic manifestation of dengue infection is rare with only 1 reported case in an adult patient. We report a case of a 6-year-old child with self-limiting post-dengue encephalopathy and Parkinsonism. This is the first reported pediatric case of post-dengue Parkinsonism and expands the neurologic manifestations associated with dengue infection in children. Clinicians should consider the possibility of post-dengue Parkinsonism in children with a history of pyrexia from endemic areas of dengue. PMID:24776518

  3. Dengue fever and dengue haemorrhagic fever in adolescents and adults.

    PubMed

    Tantawichien, Terapong

    2012-05-01

    Dengue fever (DF) is endemic in tropical and subtropical zones and the prevalence is increasing across South-east Asia, Africa, the Western Pacific and the Americas. In recent years, the spread of unplanned urbanisation, with associated substandard housing, overcrowding and deterioration in water, sewage and waste management systems, has created ideal conditions for increased transmission of the dengue virus in tropical urban centres. While dengue infection has traditionally been considered a paediatric disease, the age distribution of dengue has been rising and more cases have been observed in adolescents and adults. Furthermore, the development of tourism in the tropics has led to an increase in the number of tourists who become infected, most of whom are adults. Symptoms and risk factors for dengue haemorrhagic fever (DHF) and severe dengue differ between children and adults, with co-morbidities and incidence in more elderly patients associated with greater risk of mortality. Treatment options for DF and DHF in adults, as for children, centre round fluid replacement (either orally or intravenously, depending on severity) and antipyretics. Further data are needed on the optimal treatment of adult patients. PMID:22668446

  4. Dengue viruses – an overview

    PubMed Central

    Bäck, Anne Tuiskunen; Lundkvist, Åke

    2013-01-01

    Dengue viruses (DENVs) cause the most common arthropod-borne viral disease in man with 50–100 million infections per year. Because of the lack of a vaccine and antiviral drugs, the sole measure of control is limiting the Aedes mosquito vectors. DENV infection can be asymptomatic or a self-limited, acute febrile disease ranging in severity. The classical form of dengue fever (DF) is characterized by high fever, headache, stomach ache, rash, myalgia, and arthralgia. Severe dengue, dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS) are accompanied by thrombocytopenia, vascular leakage, and hypotension. DSS, which can be fatal, is characterized by systemic shock. Despite intensive research, the underlying mechanisms causing severe dengue is still not well understood partly due to the lack of appropriate animal models of infection and disease. However, even though it is clear that both viral and host factors play important roles in the course of infection, a fundamental knowledge gap still remains to be filled regarding host cell tropism, crucial host immune response mechanisms, and viral markers for virulence. PMID:24003364

  5. Recent advances in understanding dengue

    PubMed Central

    Yacoub, Sophie; Mongkolsapaya, Juthathip; Screaton, Gavin

    2016-01-01

    Dengue is an emerging threat to billions of people worldwide. In the last 20 years, the incidence has increased four-fold and this trend appears to be continuing. Caused by one of four viral serotypes, dengue can present as a wide range of clinical phenotypes with the severe end of the spectrum being defined by a syndrome of capillary leak, coagulopathy, and organ impairment. The pathogenesis of severe disease is thought to be in part immune mediated, but the exact mechanisms remain to be defined. The current treatment of dengue relies on supportive measures with no licensed therapeutics available to date. There have been recent advances in our understanding of a number of areas of dengue research, of which the following will be discussed in this review: the drivers behind the global dengue pandemic, viral structure and epitope binding, risk factors for severe disease and its pathogenesis, as well as the findings of recent clinical trials including therapeutics and vaccines. We conclude with current and future dengue control measures and key areas for future research. PMID:26918159

  6. Dengue Virus May Bolster Zika's Attack

    MedlinePlus

    ... news/fullstory_159534.html Dengue Virus May Bolster Zika's Attack Prior exposure to this other mosquito-borne ... dengue fever virus may increase the severity of Zika virus, a new study says. Early stage laboratory ...

  7. A review of dengue research in malaysia.

    PubMed

    Cheah, W K; Ng, K S; Marzilawati, A R; Lum, L C S

    2014-08-01

    Dengue infection is a major cause of morbidity and mortality in Malaysia. To date, much research on dengue infection conducted in Malaysia have been published. One hundred and sixty six articles related to dengue in Malaysia were found from a search through a database dedicated to indexing all original data relevant to medicine published between the years 2000-2013. Ninety articles with clinical relevance and future research implications were selected and reviewed. These papers showed evidence of an exponential increase in the disease epidemic and a varying pattern of prevalent dengue serotypes at different times. The early febrile phase of dengue infection consist of an undifferentiated fever. Clinical suspicion and ability to identify patients at risk of severe dengue infection is important. Treatment of dengue infection involves judicious use of volume expander and supportive care. Potential future research areas are discussed to narrow our current knowledge gaps on dengue infection. PMID:25417953

  8. Field Worker Evaluation of Dengue Vector Surveillance Methods: Factors That Determine Perceived Ease, Difficulty, Value, and Time Effectiveness in Australia and Malaysia.

    PubMed

    Azil, Aishah H; Ritchie, Scott A; Williams, Craig R

    2015-10-01

    This qualitative study aimed to describe field worker perceptions, evaluations of worth, and time costs of routine dengue vector surveillance methods in Cairns (Australia), Kuala Lumpur and Petaling District (Malaysia). In Cairns, the BG-Sentinel trap is a favored method for field workers because of its user-friendliness, but is not as cost-efficient as the sticky ovitrap. In Kuala Lumpur, the Mosquito Larvae Trapping Device is perceived as a solution for the inaccessibility of premises to larval surveys. Nonetheless, the larval survey method is retained in Malaysia for prompt detection of dengue vectors. For dengue vector surveillance to be successful, there needs to be not only technical, quantitative evaluations of method performance but also an appreciation of how amenable field workers are to using particular methods. Here, we report novel field worker perceptions of dengue vector surveillance methods in addition to time analysis for each method. PMID:25186807

  9. Reviewing dengue: still a neglected tropical disease?

    PubMed

    Horstick, Olaf; Tozan, Yesim; Wilder-Smith, Annelies

    2015-04-01

    Dengue is currently listed as a "neglected tropical disease" (NTD). But is dengue still an NTD or not? Classifying dengue as an NTD may carry advantages, but is it justified? This review considers the criteria for the definition of an NTD, the current diverse lists of NTDs by different stakeholders, and the commonalities and differences of dengue with other NTDs. We also review the current research gaps and research activities and the adequacy of funding for dengue research and development (R&D) (2003-2013). NTD definitions have been developed to a higher precision since the early 2000s, with the following main features: NTDs are characterised as a) poverty related, b) endemic to the tropics and subtropics, c) lacking public health attention, d) having poor research funding and shortcomings in R&D, e) usually associated with high morbidity but low mortality, and f) often having no specific treatment available. Dengue meets most of these criteria, but not all. Although dengue predominantly affects resource-limited countries, it does not necessarily only target the poor and marginalised in those countries. Dengue increasingly attracts public health attention, and in some affected countries it is now a high profile disease. Research funding for dengue has increased exponentially in the past two decades, in particular in the area of dengue vaccine development. However, despite advances in dengue research, dengue epidemics are increasing in frequency and magnitude, and dengue is expanding to new areas. Specific treatment and a highly effective vaccine remain elusive. Major research gaps exist in the area of integrated surveillance and vector control. Hence, although dengue differs from many of the NTDs, it still meets important criteria commonly used for NTDs. The current need for increased R&D spending, shared by dengue and other NTDs, is perhaps the key reason why dengue should continue to be considered an NTD. PMID:25928673

  10. Reviewing Dengue: Still a Neglected Tropical Disease?

    PubMed Central

    Horstick, Olaf; Tozan, Yesim; Wilder-Smith, Annelies

    2015-01-01

    Dengue is currently listed as a “neglected tropical disease” (NTD). But is dengue still an NTD or not? Classifying dengue as an NTD may carry advantages, but is it justified? This review considers the criteria for the definition of an NTD, the current diverse lists of NTDs by different stakeholders, and the commonalities and differences of dengue with other NTDs. We also review the current research gaps and research activities and the adequacy of funding for dengue research and development (R&D) (2003–2013). NTD definitions have been developed to a higher precision since the early 2000s, with the following main features: NTDs are characterised as a) poverty related, b) endemic to the tropics and subtropics, c) lacking public health attention, d) having poor research funding and shortcomings in R&D, e) usually associated with high morbidity but low mortality, and f) often having no specific treatment available. Dengue meets most of these criteria, but not all. Although dengue predominantly affects resource-limited countries, it does not necessarily only target the poor and marginalised in those countries. Dengue increasingly attracts public health attention, and in some affected countries it is now a high profile disease. Research funding for dengue has increased exponentially in the past two decades, in particular in the area of dengue vaccine development. However, despite advances in dengue research, dengue epidemics are increasing in frequency and magnitude, and dengue is expanding to new areas. Specific treatment and a highly effective vaccine remain elusive. Major research gaps exist in the area of integrated surveillance and vector control. Hence, although dengue differs from many of the NTDs, it still meets important criteria commonly used for NTDs. The current need for increased R&D spending, shared by dengue and other NTDs, is perhaps the key reason why dengue should continue to be considered an NTD. PMID:25928673

  11. Acanthocephala Larvae parasitizing Ameiva ameiva ameiva (Linnaeus, 1758) (Squamata: Teiidae).

    PubMed

    Macedo, Lilian Cristina; Melo, Francisco Tiago de Vasconcelos; Ávila-Pires, Teresa Cristina Sauer; Giese, Elane Guerreiro; dos Santos, Jeannie Nascimento

    2016-01-01

    Knowledge concerning the taxonomy and biology of species of Acanthocephala, helminth parasites of the helminth species of the phylum Acanthocephala, parasites of lizards in Brazilian Amazonia, is still insufficient, but reports of Acanthocephala in reptiles are becoming increasingly common in the literature. Cystacanth-stage Acanthocephalan larvae have been found in the visceral peritoneum during necropsy of Ameiva ameiva ameivalizards from the "Osvaldo Rodrigues da Cunha" Herpetology Collection of the Emílio Goeldi Museum, Belém, Pará, Brazil. The aim of this study was to present the morphological study of the Acanthocephala larvae found in A. ameiva ameiva lizard. PMID:27027551

  12. Geographical Information Systems for Dengue Surveillance

    PubMed Central

    Duncombe, Jennifer; Clements, Archie; Hu, Wenbiao; Weinstein, Philip; Ritchie, Scott; Espino, Fe Esperanza

    2012-01-01

    This review provides details on the role of Geographical Information Systems (GIS) in current dengue surveillance systems and focuses on the application of open access GIS technology to emphasize its importance in developing countries, where the dengue burden is greatest. It also advocates for increased international collaboration in transboundary disease surveillance to confront the emerging global challenge of dengue. PMID:22556070

  13. Climate and Dengue Transmission: Evidence and Implications

    PubMed Central

    Comrie, Andrew C.; Ernst, Kacey

    2013-01-01

    Background: Climate influences dengue ecology by affecting vector dynamics, agent development, and mosquito/human interactions. Although these relationships are known, the impact climate change will have on transmission is unclear. Climate-driven statistical and process-based models are being used to refine our knowledge of these relationships and predict the effects of projected climate change on dengue fever occurrence, but results have been inconsistent. Objective: We sought to identify major climatic influences on dengue virus ecology and to evaluate the ability of climate-based dengue models to describe associations between climate and dengue, simulate outbreaks, and project the impacts of climate change. Methods: We reviewed the evidence for direct and indirect relationships between climate and dengue generated from laboratory studies, field studies, and statistical analyses of associations between vectors, dengue fever incidence, and climate conditions. We assessed the potential contribution of climate-driven, process-based dengue models and provide suggestions to improve their performance. Results and Discussion: Relationships between climate variables and factors that influence dengue transmission are complex. A climate variable may increase dengue transmission potential through one aspect of the system while simultaneously decreasing transmission potential through another. This complexity may at least partly explain inconsistencies in statistical associations between dengue and climate. Process-based models can account for the complex dynamics but often omit important aspects of dengue ecology, notably virus development and host–species interactions. Conclusion: Synthesizing and applying current knowledge of climatic effects on all aspects of dengue virus ecology will help direct future research and enable better projections of climate change effects on dengue incidence. Citation: Morin CW, Comrie AC, Ernst KC. 2013. Climate and dengue transmission

  14. Community-based dengue prevention programs in Puerto Rico: impact on knowledge, behavior, and residential mosquito infestation.

    PubMed

    Winch, Peter J; Leontsini, Elli; Rigau-Pérez, José G; Ruiz-Pérez, Mervin; Clark, Gary G; Gubler, Duane J

    2002-10-01

    Dengue is a major health burden in Puerto Rico. Televised public service announcements and posters, elementary and pre-school educational programs, and an exhibit at the Children's Museum in Old San Juan were evaluated separately using knowledge and practices surveys administered to children and their parents, surveys of house lots for larval container habitats, focus groups, and interviews with program organizers and participants. Exposure to the programs was associated with increased dengue-related knowledge, increased proportion of tires protected from rain, decreased proportion of water storage containers positive for mosquito larvae, and increased indoor use of aerosol insecticides. Exposure to the elementary school program was associated with slightly lower indices of residential mosquito infestation. The programs have resulted in high levels of awareness, some behavior change, and limited change in larval indices. Greater emphasis on the skills necessary for community members to keep containers free of mosquito larvae would increase program effectiveness. PMID:12452490

  15. Cells in Dengue Virus Infection In Vivo

    PubMed Central

    Noisakran, Sansanee; Onlamoon, Nattawat; Songprakhon, Pucharee; Hsiao, Hui-Mien; Chokephaibulkit, Kulkanya; Perng, Guey Chuen

    2010-01-01

    Dengue has been recognized as one of the most important vector-borne emerging infectious diseases globally. Though dengue normally causes a self-limiting infection, some patients may develop a life-threatening illness, dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS). The reason why DHF/DSS occurs in certain individuals is unclear. Studies in the endemic regions suggest that the preexisting antibodies are a risk factor for DHF/DSS. Viremia and thrombocytopenia are the key clinical features of dengue virus infection in patients. The amounts of virus circulating in patients are highly correlated with severe dengue disease, DHF/DSS. Also, the disturbance, mainly a transient depression, of hematological cells is a critical clinical finding in acute dengue patients. However, the cells responsible for the dengue viremia are unresolved in spite of the intensive efforts been made. Dengue virus appears to replicate and proliferate in many adapted cell lines, but these in vitro properties are extremely difficult to be reproduced in primary cells or in vivo. This paper summarizes reports on the permissive cells in vitro and in vivo and suggests a hematological cell lineage for dengue virus infection in vivo, with the hope that a new focus will shed light on further understanding of the complexities of dengue disease. PMID:22331984

  16. Dengue infection: a growing global health threat.

    PubMed

    Hemungkorn, Marisa; Thisyakorn, Usa; Thisyakorn, Chule

    2007-10-01

    Dengue infection, one of the most devastating mosquito-borne viral diseases in humans, is now a significant problem in several tropical countries. The disease, caused by the four dengue virus serotypes, ranges from asymptomatic infection to undifferentiated fever, dengue fever (DF), and severe dengue hemorrhagic fever (DHF) with or without shock. DHF is characterized by fever, bleeding diathesis and a tendency to develop a potentially fatal shock syndrome. Consistent hematological findings include vasculopathy, coagulopathy, and thrombocytopenia. There are increasing reports of dengue infection with unusual manifestations that mainly involve cerebral and hepatic symptoms. Laboratory diagnosis includes virus isolation, serology, and detection of dengue ribonucleic acid. Successful treatment, which is mainly supportive, depends on early recognition of the disease and careful monitoring for shock. Prevention depends primarily on control of the mosquito vector. Further study of the pathogenesis of DHF is required for the development of a safe and effective dengue vaccine. PMID:20103874

  17. Reemergence of Dengue in Southern Texas, 2013

    PubMed Central

    Thomas, Dana L.; Santiago, Gilberto A.; Abeyta, Roman; Hinojosa, Steven; Torres-Velasquez, Brenda; Adam, Jessica K.; Evert, Nicole; Caraballo, Elba; Hunsperger, Elizabeth; Muñoz-Jordán, Jorge L.; Smith, Brian; Banicki, Alison; Tomashek, Kay M.; Gaul, Linda

    2016-01-01

    During a dengue epidemic in northern Mexico, enhanced surveillance identified 53 laboratory-positive cases in southern Texas; 26 (49%) patients acquired the infection locally, and 29 (55%) were hospitalized. Of 83 patient specimens that were initially IgM negative according to ELISA performed at a commercial laboratory, 14 (17%) were dengue virus positive by real-time reverse transcription PCR performed at the Centers for Disease Control and Prevention. Dengue virus types 1 and 3 were identified, and molecular phylogenetic analysis demonstrated close identity with viruses that had recently circulated in Mexico and Central America. Of 51 household members of 22 dengue case-patients who participated in household investigations, 6 (12%) had been recently infected with a dengue virus and reported no recent travel, suggesting intrahousehold transmission. One household member reported having a recent illness consistent with dengue. This outbreak reinforces emergence of dengue in southern Texas, particularly when incidence is high in northern Mexico. PMID:27191223

  18. Novel concept on antiviral strategies to dengue.

    PubMed

    Lo, Yu-Chih; Perng, Guey Chuen

    2016-06-01

    Recent evidence has revealed that asymptomatic and/or persistent dengue virus (DENV) infections play a role in the cycling pattern of dengue outbreaks. These findings add a new dimension to the continually evolving search for effective prevention strategies in dengue. Disappointing outcomes of clinical trials in anti-dengue modalities have become commonplace. These failures may result from confounding variables and/or unresolved scientific issues that surround dengue, including the replication cycle of DENV in a natural setting, the target cells and reservoir for viral replication in vivo, and the effect of asymptomatic/persistent carriers in the dissemination of dengue. This article sets forth to address these issues using the most updated information available in the literature and to propose a novel antiviral strategy for the prevention and control of dengue. PMID:27284691

  19. Reemergence of Dengue in Southern Texas, 2013.

    PubMed

    Thomas, Dana L; Santiago, Gilberto A; Abeyta, Roman; Hinojosa, Steven; Torres-Velasquez, Brenda; Adam, Jessica K; Evert, Nicole; Caraballo, Elba; Hunsperger, Elizabeth; Muñoz-Jordán, Jorge L; Smith, Brian; Banicki, Alison; Tomashek, Kay M; Gaul, Linda; Sharp, Tyler M

    2016-06-01

    During a dengue epidemic in northern Mexico, enhanced surveillance identified 53 laboratory-positive cases in southern Texas; 26 (49%) patients acquired the infection locally, and 29 (55%) were hospitalized. Of 83 patient specimens that were initially IgM negative according to ELISA performed at a commercial laboratory, 14 (17%) were dengue virus positive by real-time reverse transcription PCR performed at the Centers for Disease Control and Prevention. Dengue virus types 1 and 3 were identified, and molecular phylogenetic analysis demonstrated close identity with viruses that had recently circulated in Mexico and Central America. Of 51 household members of 22 dengue case-patients who participated in household investigations, 6 (12%) had been recently infected with a dengue virus and reported no recent travel, suggesting intrahousehold transmission. One household member reported having a recent illness consistent with dengue. This outbreak reinforces emergence of dengue in southern Texas, particularly when incidence is high in northern Mexico. PMID:27191223

  20. Biomarkers of severe dengue disease - a review.

    PubMed

    John, Daisy Vanitha; Lin, Yee-Shin; Perng, Guey Chuen

    2015-01-01

    Dengue virus infection presents a wide spectrum of manifestations including asymptomatic condition, dengue fever (DF), or severe forms, such as dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) in affected individuals. The early prediction of severe dengue in patients without any warning signs who may later develop severe DHF is very important to choose appropriate intensive supportive therapy since available vaccines for immunization are yet to be approved. Severe dengue responses include T and B cell activation and apoptosis, cytokine storm, hematologic disorders and complement activation. Cytokines, complement and other unidentified factors may transiently act on the endothelium and alter normal fluid barrier function of the endothelial cells and cause plasma leakage. In this review, the host factors such as activated immune and endothelial cells and their products which can be utilized as biomarkers for severe dengue disease are discussed. PMID:26462910

  1. Lethal Dengue Virus Infection: A Forensic Overview.

    PubMed

    Byard, Roger W

    2016-06-01

    Dengue virus is a single-stranded RNA virus that is a member of the family Flaviviridae, genus Flavivirus. It is usually transmitted by the female Aedes aegypti mosquito. Dengue fever is a febrile illness caused by 1 of 4 serotypes of the virus, which may progress to dengue hemorrhagic fever or dengue shock syndrome. The mortality rate of untreated dengue shock syndrome is more than 20%. The reported incidence has increased 30-fold for the past 50 years with an estimated 50 to 100 million dengue infections globally each year, which includes 22,000 deaths. Because of this rapid increase in numbers, more cases will be seen in forensic mortuaries, with diagnostic problems arising from nonspecific or unusual manifestations. In this review, the clinicopathological features of dengue viral infection are evaluated. Adequate blood and tissue sampling at the time of autopsy is mandatory for successful microbiological identification and characterization. PMID:27093563

  2. Points for Consideration for dengue vaccine introduction - recommendations by the Dengue Vaccine Initiative.

    PubMed

    Lim, Jacqueline Kyungah; Lee, Yong-Seok; Wilder-Smith, Annelies; Thiry, Georges; Mahoney, Richard; Yoon, In-Kyu

    2016-04-01

    Dengue is a public health problem in the tropics and subtropics. There are several vaccine candidates in clinical development. However, there may be gaps in the new vaccine introduction after vaccine licensure before it becomes available in developing countries. In anticipation of the first dengue vaccine candidate to be licensed, Dengue Vaccine Initiative (DVI) and, its predecessor, Pediatric Dengue Vaccine Initiative (PDVI) have been working on points for consideration to accelerate evidence-based dengue vaccine introduction, once a vaccine becomes available. In this paper, we review the history of PDVI and its successor, the DVI, and elaborate on the points of consideration for dengue vaccine introduction. PMID:26651238

  3. [Society, economy, inequities and dengue].

    PubMed

    Kouri, Gustavo; Pelegrino, José L; Munster, Blanca María; Guzmán, María G

    2007-01-01

    Dengue and dengue hemorrhagic fever in the Americas have been on the rise throughout the 1990s, with the highest number -over one million cases- reported in 2002. This paper analyzed the situation of dengue in the region and discussed the determining factors that account for the rise of the disease, making emphasis on socioeconomic factors, such as poverty, inequality, migrations and the lack of access to basic services, which are the most influential in perpetuating this disease in most countries. Considering that a safe and accessible vaccine is now unavailable, basic principles of vector control combined with political willingness, inter-sectoral involvement, active community participation and the tightening of health legislation were also examined as the only viable solution at present. PMID:23427454

  4. Challenges and future perspective for dengue vector control in the Western Pacific Region

    PubMed Central

    Christophel, Eva Maria; Gopinath, Deyer; Abdur, Rashid Md.; Vectorborne, Other; Diseases, Parasitic

    2011-01-01

    Dengue remains a significant public health issue in the Western Pacific Region. In the absence of a vaccine, vector control is the mainstay for dengue prevention and control. In this paper we describe vector surveillance and vector control in the Western Pacific countries and areas. Vector surveillance and control strategies used by countries and areas of the Western Pacific Region vary. Vector control strategies include chemical, biological and environmental management that mainly target larval breeding sites. The use of insecticides targeting larvae and adult mosquitoes remains the mainstay of vector control programmes. Existing vector control tools have several limitations in terms of cost, delivery and long-term sustainability. However, there are several new innovative tools in the pipeline. These include Release of Insects Carrying a Dominant Lethal system and Wolbachia, an endosymbiotic bacterium, to inhibit dengue virus in the vector. In addition, the use of biological control such as larvivorous fish in combination with community participation has potential to be scaled up. Any vector control strategy should be selected based on evidence and appropriateness for the entomological and epidemiological setting and carried out in both inter-epidemic and epidemic periods. Community participation and interagency collaboration are required for effective and sustainable dengue prevention and control. Countries and areas are now moving towards integrated vector management. PMID:23908883

  5. [Visceral and cutaneous larva migrans].

    PubMed

    Petithory, Jean-Claude

    2007-11-30

    The syndrome of visceral larva migrans was described for the first time in 1952 by Beaver. He demonstrated that the presence of nematodes larvae, particularly in the liver, were those of Toxocara canis and T. cati. Baylisascaris procyonis, the common racoon ascarid in the U.S.A. can also cause serious diseases in human. Digestive and respiratory clinical symptoms are usually moderate, however severe disease resulting from invasion of the myocardium or the brain has been reported. A blood hypereosinophilia is usually present the first few years after infection. Diagnosis uses serological methods, among them the ELISA test. Ocular larva is also possible with in that case, immunological modifications of the aqueous. Cutaneous larva migrans characterized by a linear, progressing, serpigenous eruption and intense itching is easy to diagnose. Larva migrans is due to dogs, cats and horses helminths. Dogs and cats (referred here as pets) now receive antihelmintitic treatments and parasites are now in decrease. PMID:18326429

  6. Evidence based community mobilization for dengue prevention in Nicaragua and Mexico (Camino Verde, the Green Way): cluster randomized controlled trial

    PubMed Central

    Nava-Aguilera, Elizabeth; Arosteguí, Jorge; Morales-Perez, Arcadio; Suazo-Laguna, Harold; Legorreta-Soberanis, José; Hernandez-Alvarez, Carlos; Fernandez-Salas, Ildefonso; Paredes-Solís, Sergio; Balmaseda, Angel; Cortés-Guzmán, Antonio Juan; Serrano de los Santos, René; Coloma, Josefina; Ledogar, Robert J; Harris, Eva

    2015-01-01

    Objective To test whether community mobilization adds effectiveness to conventional dengue control. Design Pragmatic open label parallel group cluster randomized controlled trial. Those assessing the outcomes and analyzing the data were blinded to group assignment. Centralized computerized randomization after the baseline study allocated half the sites to intervention, stratified by country, evidence of recent dengue virus infection in children aged 3-9, and vector indices. Setting Random sample of communities in Managua, capital of Nicaragua, and three coastal regions in Guerrero State in the south of Mexico. Participants Residents in a random sample of census enumeration areas across both countries: 75 intervention and 75 control clusters (about 140 households each) were randomized and analyzed (60 clusters in Nicaragua and 90 in Mexico), including 85 182 residents in 18 838 households. Interventions A community mobilization protocol began with community discussion of baseline results. Each intervention cluster adapted the basic intervention—chemical-free prevention of mosquito reproduction—to its own circumstances. All clusters continued the government run dengue control program. Main outcome measures Primary outcomes per protocol were self reported cases of dengue, serological evidence of recent dengue virus infection, and conventional entomological indices (house index: households with larvae or pupae/households examined; container index: containers with larvae or pupae/containers examined; Breteau index: containers with larvae or pupae/households examined; and pupae per person: pupae found/number of residents). Per protocol secondary analysis examined the effect of Camino Verde in the context of temephos use. Results With cluster as the unit of analysis, serological evidence from intervention sites showed a lower risk of infection with dengue virus in children (relative risk reduction 29.5%, 95% confidence interval 3.8% to 55.3%), fewer reports of

  7. Dengue fever complicated by hemophagocytosis

    PubMed Central

    Koshy, Maria; Mishra, Ajay Kumar; Agrawal, Bhumi; Kurup, Akhil Rajendra; Hansdak, Samuel George

    2016-01-01

    Dengue is a common acute viral febrile illness in the tropics. Although the usual presentation is that of a self-limiting illness, its complications are protean. We report a 29-year-old man who presented with an acute febrile illness and was diagnosed with dengue hemorrhagic fever. Despite appropriate supportive therapy, the patient initially improved, but subsequently had clinical deterioration. Evaluation revealed features of hemophagocytic lymphohistiocytosis. He was successfully treated with glucocorticoids and had an uneventful recovery. This case adds to the limited adult cases of virus-associated hemophagocytic syndrome in the literature and the need for prompt recognition and treatment of this rare complication. PMID:27274854

  8. Dengue fever complicated by hemophagocytosis.

    PubMed

    Koshy, Maria; Mishra, Ajay Kumar; Agrawal, Bhumi; Kurup, Akhil Rajendra; Hansdak, Samuel George

    2016-01-01

    Dengue is a common acute viral febrile illness in the tropics. Although the usual presentation is that of a self-limiting illness, its complications are protean. We report a 29-year-old man who presented with an acute febrile illness and was diagnosed with dengue hemorrhagic fever. Despite appropriate supportive therapy, the patient initially improved, but subsequently had clinical deterioration. Evaluation revealed features of hemophagocytic lymphohistiocytosis. He was successfully treated with glucocorticoids and had an uneventful recovery. This case adds to the limited adult cases of virus-associated hemophagocytic syndrome in the literature and the need for prompt recognition and treatment of this rare complication. PMID:27274854

  9. EVALUATION OF SUBLETHAL EFFECTS OF Ipomoea cairica LINN. EXTRACT ON LIFE HISTORY TRAITS OF DENGUE VECTORS

    PubMed Central

    ZUHARAH, Wan Fatma; AHBIRAMI, Rattanam; DIENG, Hamady; THIAGALETCHUMI, Maniam; FADZLY, Nik

    2016-01-01

    Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity) and eggs hatchability (fertility) in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors. PMID:27253746

  10. EVALUATION OF SUBLETHAL EFFECTS OF Ipomoea cairica LINN. EXTRACT ON LIFE HISTORY TRAITS OF DENGUE VECTORS.

    PubMed

    Zuharah, Wan Fatma; Ahbirami, Rattanam; Dieng, Hamady; Thiagaletchumi, Maniam; Fadzly, Nik

    2016-01-01

    Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity) and eggs hatchability (fertility) in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors. PMID:27253746

  11. Surveillance for dengue and dengue-associated neurologic syndromes in the United States.

    PubMed

    Waterman, Stephen H; Margolis, Harold S; Sejvar, James J

    2015-05-01

    Autochthonous dengue virus transmission has occurred in the continental United States with increased frequency during the last decade; the principal vector, Aedes aegypti, has expanded its geographic distribution in the southern United States. Dengue, a potentially fatal arboviral disease, is underreported, and US clinicians encountering patients with acute febrile illness consistent with dengue are likely to not be fully familiar with dengue diagnosis and management. Recently, investigators suggested that an outbreak of dengue likely occurred in Houston during 2003 based on retrospective laboratory testing of hospitalized cases with encephalitis and aseptic meningitis. Although certain aspects of the Houston testing results and argument for local transmission are doubtful, the report highlights the importance of prospective surveillance for dengue in Aedes-infested areas of the United States, the need for clinical training on dengue and its severe manifestations, and the need for laboratory testing in domestic patients presenting with febrile neurologic illness in these regions to include dengue. PMID:25371183

  12. Is drought helping or killing dengue? Investigation of spatiotemporal relationship between dengue fever and drought

    NASA Astrophysics Data System (ADS)

    Lee, Chieh-Han; Yu, Hwa-Lung

    2015-04-01

    Dengue Fever is a vector-borne disease that is transmitted between human and mosquitos in tropical and sub-tropical regions. Previous studies have found significant relationship between the epidemic of dengue cases and climate variables, especially temperature and precipitation. Besides, the natural phenomena (e.g., drought) are considered that significantly drop the number of dengue cases by killing vector's breeding environment. However, in Kaohsiung City, Taiwan, there are evidences that the temporal pattern of dengue is correlated to drought events. Kaohsiung City experienced two main dengue outbreaks in 2002 and 2014 that both years were confirmed with serious drought. Especially in 2014, Kaohsiung City was suffered from extremely dengue outbreak in 2014 that reported the highest number of dengue cases in the history. This study constructs the spatiotemporal model of dengue incidences and index of drought events (Standardized Precipitation Index, SPI) based on the distributed lag nonlinear model (DLNM). Other meteorological measures are also included in the analysis.

  13. The dengue vaccine pipeline: Implications for the future of dengue control.

    PubMed

    Schwartz, Lauren M; Halloran, M Elizabeth; Durbin, Anna P; Longini, Ira M

    2015-06-26

    Dengue has become the most rapidly expanding mosquito-borne infectious disease on the planet, surpassing malaria and infecting at least 390 million people per year. There is no effective treatment for dengue illness other than supportive care, especially for severe cases. Symptoms can be mild or life-threatening as in dengue hemorrhagic fever and dengue shock syndrome. Vector control has been only partially successful in decreasing dengue transmission. The potential use of safe and effective tetravalent dengue vaccines is an attractive addition to prevent disease or minimize the possibility of epidemics. There are currently no licensed dengue vaccines. This review summarizes the current status of all dengue vaccine candidates in clinical evaluation. Currently five candidate vaccines are in human clinical trials. One has completed two Phase III trials, two are in Phase II trials, and three are in Phase I testing. PMID:25989449

  14. Surveillance for Dengue and Dengue-Associated Neurologic Syndromes in the United States

    PubMed Central

    Waterman, Stephen H.; Margolis, Harold S.; Sejvar, James J.

    2015-01-01

    Autochthonous dengue virus transmission has occurred in the continental United States with increased frequency during the last decade; the principal vector, Aedes aegypti, has expanded its geographic distribution in the southern United States. Dengue, a potentially fatal arboviral disease, is underreported, and US clinicians encountering patients with acute febrile illness consistent with dengue are likely to not be fully familiar with dengue diagnosis and management. Recently, investigators suggested that an outbreak of dengue likely occurred in Houston during 2003 based on retrospective laboratory testing of hospitalized cases with encephalitis and aseptic meningitis. Although certain aspects of the Houston testing results and argument for local transmission are doubtful, the report highlights the importance of prospective surveillance for dengue in Aedes-infested areas of the United States, the need for clinical training on dengue and its severe manifestations, and the need for laboratory testing in domestic patients presenting with febrile neurologic illness in these regions to include dengue. PMID:25371183

  15. Microgavage of zebrafish larvae.

    PubMed

    Cocchiaro, Jordan L; Rawls, John F

    2013-01-01

    The zebrafish has emerged as a powerful model organism for studying intestinal development(1-5), physiology(6-11), disease(12-16), and host-microbe interactions(17-25). Experimental approaches for studying intestinal biology often require the in vivo introduction of selected materials into the lumen of the intestine. In the larval zebrafish model, this is typically accomplished by immersing fish in a solution of the selected material, or by injection through the abdominal wall. Using the immersion method, it is difficult to accurately monitor or control the route or timing of material delivery to the intestine. For this reason, immersion exposure can cause unintended toxicity and other effects on extraintestinal tissues, limiting the potential range of material amounts that can be delivered into the intestine. Also, the amount of material ingested during immersion exposure can vary significantly between individual larvae(26). Although these problems are not encountered during direct injection through the abdominal wall, proper injection is difficult and causes tissue damage which could influence experimental results. We introduce a method for microgavage of zebrafish larvae. The goal of this method is to provide a safe, effective, and consistent way to deliver material directly to the lumen of the anterior intestine in larval zebrafish with controlled timing. Microgavage utilizes standard embryo microinjection and stereomicroscopy equipment common to most laboratories that perform zebrafish research. Once fish are properly positioned in methylcellulose, gavage can be performed quickly at a rate of approximately 7-10 fish/ min, and post-gavage survival approaches 100% depending on the gavaged material. We also show that microgavage can permit loading of the intestinal lumen with high concentrations of materials that are lethal to fish when exposed by immersion. To demonstrate the utility of this method, we present a fluorescent dextran microgavage assay that can be

  16. Fatal Staphylococcal Infection following Classic Dengue Fever

    PubMed Central

    Araújo, Stanley Almeida; Moreira, Daniel Ribeiro; Veloso, Juliana Marcia Ribeiro; Silva, Jenaine Oliveira; Barros, Vera Lucia Souza Reis; Nobre, Vandack

    2010-01-01

    Dengue represents an important public health issue in many tropical areas, leading to high morbidity and the employment of substantial health resources. Even though the number of fatalities related to dengue is unknown, several reports warn about the potential occurrence of severe infections and even death. The clinical spectrum of dengue is highly variable, ranging from a mild flu-like syndrome to severe disease, with shock and hemorrhage. The occurrence of bacterial superinfection, or coinfection, in patients with dengue has been noted by some authors, but the available information comes from anecdotic reports. In this study, we show the clinical and anatomopathological data of a patient infected with dengue, who subsequently died of acute multi-organic failure related to Staphylococcus aureus infection. The autopsy revealed a severe disseminated staphylococcal disease and confirmed dengue infection. PMID:20810838

  17. Epidemiological Scenario of Dengue in Brazil

    PubMed Central

    Fares, Rafaelle C. G.; Souza, Katia P. R.; Añez, Germán; Rios, Maria

    2015-01-01

    Dengue is the most important reemerging mosquito-borne viral disease worldwide. It is caused by any of four Dengue virus types or serotypes (DENV-1 to DENV-4) and is transmitted by mosquitoes from the genus Aedes. Ecological changes have favored the geographic expansion of the vector and, since the dengue pandemic in the Asian and Pacific regions, the infection became widely distributed worldwide, reaching Brazil in 1845. The incidence of dengue in Brazil has been frequently high, and the number of cases in the country has at some point in time represented up to 60% of the dengue reported cases worldwide. This review addresses vector distribution, dengue outbreaks, circulating serotypes and genotypes, and prevention approaches being utilized in Brazil. PMID:26413514

  18. The global distribution and burden of dengue

    PubMed Central

    Bhatt, Samir; Gething, Peter W.; Brady, Oliver J.; Messina, Jane P.; Farlow, Andrew W.; Moyes, Catherine L.; Drake, John M.; Brownstein, John S.; Hoen, Anne G.; Sankoh, Osman; Myers, Monica F.; George, Dylan B.; Jaenisch, Thomas; Wint, G.R. William; Simmons, Cameron P.; Scott, Thomas W.; Farrar, Jeremy J.; Hay, Simon I.

    2013-01-01

    Dengue is a systemic viral infection transmitted between humans by Aedes mosquitoes1. For some patients dengue is a life-threatening illness2. There are currently no licensed vaccines or specific therapeutics, and substantial vector control efforts have not stopped its rapid emergence and global spread3. The contemporary worldwide distribution of the risk of dengue virus infection4 and its public health burden are poorly known2,5. Here we undertake an exhaustive assembly of known records of dengue occurrence worldwide, and use a formal modelling framework to map the global distribution of dengue risk. We then pair the resulting risk map with detailed longitudinal information from dengue cohort studies and population surfaces to infer the public health burden of dengue in 2010. We predict dengue to be ubiquitous throughout the tropics, with local spatial variations in risk influenced strongly by rainfall, temperature and the degree of urbanisation. Using cartographic approaches, we estimate there to be 390 million (95 percent credible interval 284-528) dengue infections per year, of which 96 million (67-136) manifest apparently (any level of clinical or sub-clinical severity). This infection total is more than three times the dengue burden estimate of the World Health Organization2. Stratification of our estimates by country allows comparison with national dengue reporting, after taking into account the probability of an apparent infection being formally reported. The most notable differences are discussed. These new risk maps and infection estimates provide novel insights into the global, regional and national public health burden imposed by dengue. We anticipate that they will provide a starting point for a wider discussion about the global impact of this disease and will help guide improvements in disease control strategies using vaccine, drug and vector control methods and in their economic evaluation. [285] PMID:23563266

  19. Dengue-associated acute kidney injury

    PubMed Central

    Oliveira, João Fernando Picollo; Burdmann, Emmanuel A.

    2015-01-01

    Dengue is presently the most relevant viral infection transmitted by a mosquito bite that represents a major threat to public health worldwide. Acute kidney injury (AKI) is a serious and potentially lethal complication of this disease, and the actual incidence is unknown. In this review, we will assess the most relevant epidemiological and clinical data regarding dengue and the available evidence on the frequency, etiopathogenesis, outcomes and treatment of dengue-associated AKI. PMID:26613023

  20. Tetravalent Dengue Vaccine: A Review in the Prevention of Dengue Disease.

    PubMed

    Scott, Lesley J

    2016-09-01

    Tetravalent, live-attenuated, dengue vaccine (Dengvaxia(®); CYD-TDV) is the first vaccine approved for the prevention of dengue disease caused by dengue virus (DENV) serotypes 1-4 in individuals aged 9-45 or 9-60 years living in high dengue endemic areas. This narrative review discusses the immunogenicity, protective efficacy, reactogenicity and safety of CYD-TDV in the prevention of dengue disease. In Latin American and Asian phase 3 trials in children and adolescents (n > 30,000), the recommended three-dose CYD-TDV regimen was efficacious in preventing virologically-confirmed dengue (VCD) during the period from 28 days after the last dose (month 13) to month 25, meeting the primary endpoint criteria. Protective efficacy against VCD in the respective individual trials was 60.8 and 56.5 % (primary analysis). During the 25-month active surveillance phase, CYD-TDV also provided protective efficacy against VCD, severe dengue, any grade of dengue haemorrhagic fever and VCD-related hospitalization in children aged 9 years and older. CYD-TDV was generally well tolerated, with no safety concerns identified after up to 4 years' follow-up (i.e. from post dose 1) in ongoing long-term studies. Based on evidence from the dengue clinical trial program, the WHO SAGE recommended that countries with high dengue endemicity consider introducing CYD-TDV as part of an integrated disease prevention strategy to lower disease burden. Pharmacoeconomic considerations will be pivotal to implementing dengue vaccination prevention strategies in these countries. The availability of a dengue vaccine is considered essential if the 2012 WHO global strategy targets for reducing the burden of dengue disease by 2020 are to be attained. Hence, CYD-TDV represents a major advance for the prevention of dengue disease in high dengue endemic regions. PMID:27506852

  1. Culturing larvae of marine invertebrates.

    PubMed

    Strathmann, Richard R

    2014-01-01

    Larvae of marine invertebrates cultured in the laboratory experience conditions that they do not encounter in nature, but development and survival to metamorphic competence can be obtained in such cultures. This protocol emphasizes simple methods suitable for a wide variety of larvae. Culturing larvae requires seawater of adequate quality and temperature within the tolerated range. Beyond that, feeding larvae require appropriate food, but a few kinds of algae and animals are sufficient as food for diverse larvae. Nontoxic materials include glass, many plastics, hot-melt glue, and some solvents, once evaporated. Cleaners that do not leave toxic residues after rinsing include dilute hydrochloric or acetic acid, sodium hypochlorite (commercial bleach), and ethanol. Materials that can leave toxic residues, such as formaldehyde, glutaraldehyde, detergents, and hand lotions, should be avoided, especially with batch cultures that lack continuously renewed water. Reverse filtration can be used to change water gently at varying frequencies, depending on temperature and the kinds of food that are provided. Bacterial growth can be limited by antibiotics, but antibiotics are often unnecessary. Survival and growth are increased by low concentrations of larvae and stirring of large or dense cultures. One method of stirring large numbers of containers is a rack of motor-driven paddles. Most of the methods and materials are inexpensive and portable. If necessary, a room within a few hours of the sea could be temporarily equipped for larval culture. PMID:24567204

  2. Economic Cost of Dengue in Puerto Rico

    PubMed Central

    Halasa, Yara A.; Shepard, Donald S.; Zeng, Wu

    2012-01-01

    Dengue, endemic in Puerto Rico, reached a record high in 2010. To inform policy makers, we derived annual economic cost. We assessed direct and indirect costs of hospitalized and ambulatory dengue illness in 2010 dollars through surveillance data and interviews with 100 laboratory-confirmed dengue patients treated in 2008–2010. We corrected for underreporting by using setting-specific expansion factors. Work absenteeism because of a dengue episode exceeded the absenteeism for an episode of influenza or acute otitis media. From 2002 to 2010, the aggregate annual cost of dengue illness averaged $38.7 million, of which 70% was for adults (age 15+ years). Hospitalized patients accounted for 63% of the cost of dengue illness, and fatal cases represented an additional 17%. Households funded 48% of dengue illness cost, the government funded 24%, insurance funded 22%, and employers funded 7%. Including dengue surveillance and vector control activities, the overall annual cost of dengue was $46.45 million ($12.47 per capita). PMID:22556069

  3. Dengue blood analysis by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Rehman, A.; Anwar, S.; Firdous, S.; Ahmed, M.; Rasheed, R.; Nawaz, M.

    2012-06-01

    In this work Raman spectra of normal and dengue infected serum and whole blood were analyzed. In normal whole blood and serum characteristic peaks were observed when excited at 442 and 532 nm. In dengue whole blood and serum all peaks found to be blue shifted with reduced Raman intensity. Dengue whole blood and serum shows two peaks at 1614 and 1750 cm-1 which are due to presence of Immunoglobulin antibodies IgG and IgM. Whole study provides a route of information for diagnosis of dengue viral infection.

  4. Use of Saliva for Early Dengue Diagnosis

    PubMed Central

    Ng, Lee-Ching

    2011-01-01

    Background The necessity of a venous blood collection in all dengue diagnostic assays and the high cost of tests that are available for testing during the viraemic period hinder early detection of dengue cases and thus could delay cluster management. This study reports the utility of saliva in an assay that detects dengue virus (DENV)–specific immunoglobulin A (Ig A) early in the phase of a dengue infection. Methods and Findings Using an antigen capture anti-DENV IgA (ACA) ELISA technique, we tested saliva samples collected from dengue-confirmed patients. The sensitivity within 3 days from fever onset was over 36% in primary dengue infections. The performance is markedly better in secondary infections, with 100% sensitivity reported in saliva samples from day 1 after fever onset. Serum and salivary IgA levels showed good correlation (Pearson's r = 0.69, p<0.001). Specificity was found to be 97%. Conclusion Our findings suggest that this technique would be very useful in dengue endemic regions, where the majority of dengue cases are secondary. The ACA-ELISA is easy to perform, cost effective, and especially useful in laboratories without sophisticated equipment. Our findings established the usefulness and reliability of saliva for early dengue diagnosis. PMID:21572982

  5. Dengue Fever: Causes, Complications, and Vaccine Strategies.

    PubMed

    Khetarpal, Niyati; Khanna, Ira

    2016-01-01

    Dengue is a highly endemic infectious disease of the tropical countries and is rapidly becoming a global burden. It is caused by any of the 4 serotypes of dengue virus and is transmitted within humans through female Aedes mosquitoes. Dengue disease varies from mild fever to severe conditions of dengue hemorrhagic fever and shock syndrome. Globalization, increased air travel, and unplanned urbanization have led to increase in the rate of infection and helped dengue to expand its geographic and demographic distribution. Dengue vaccine development has been a challenging task due to the existence of four antigenically distinct dengue virus serotypes, each capable of eliciting cross-reactive and disease-enhancing antibody response against the remaining three serotypes. Recently, Sanofi Pasteur's chimeric live-attenuated dengue vaccine candidate has been approved in Mexico, Brazil, and Philippines for usage in adults between 9 and 45 years of age. The impact of its limited application to the public health system needs to be evaluated. Simultaneously, the restricted application of this vaccine candidate warrants continued efforts in developing a dengue vaccine candidate which is additionally efficacious for infants and naïve individuals. In this context, alternative strategies of developing a designed vaccine candidate which does not allow production of enhancing antibodies should be explored, as it may expand the umbrella of efficacy to include infants and naïve individuals. PMID:27525287

  6. Recent progress in dengue vaccine development.

    PubMed

    Wei, Jianchun; Chen, Hui; An, Jing

    2014-12-01

    Dengue virus (DENV) has four distinct serotypes. DENV infection can result in classic dengue fever and life-threatening dengue hemorrhagic fever/dengue shock syndrome. In recent decades, DENV infection has become an important public health concern in epidemic-prone areas. Vaccination is the most effective measure to prevent and control viral infections. However, several challenges impede the development of effective DENV vaccines, such as the lack of suitable animal models and the antibody-dependent enhancement phenomenon. Although no licensed DENV vaccine is available, significant progress has been made. This review summarizes candidate DENV vaccines from recent investigations. PMID:25547681

  7. Dengue Fever: Causes, Complications, and Vaccine Strategies

    PubMed Central

    Khanna, Ira

    2016-01-01

    Dengue is a highly endemic infectious disease of the tropical countries and is rapidly becoming a global burden. It is caused by any of the 4 serotypes of dengue virus and is transmitted within humans through female Aedes mosquitoes. Dengue disease varies from mild fever to severe conditions of dengue hemorrhagic fever and shock syndrome. Globalization, increased air travel, and unplanned urbanization have led to increase in the rate of infection and helped dengue to expand its geographic and demographic distribution. Dengue vaccine development has been a challenging task due to the existence of four antigenically distinct dengue virus serotypes, each capable of eliciting cross-reactive and disease-enhancing antibody response against the remaining three serotypes. Recently, Sanofi Pasteur's chimeric live-attenuated dengue vaccine candidate has been approved in Mexico, Brazil, and Philippines for usage in adults between 9 and 45 years of age. The impact of its limited application to the public health system needs to be evaluated. Simultaneously, the restricted application of this vaccine candidate warrants continued efforts in developing a dengue vaccine candidate which is additionally efficacious for infants and naïve individuals. In this context, alternative strategies of developing a designed vaccine candidate which does not allow production of enhancing antibodies should be explored, as it may expand the umbrella of efficacy to include infants and naïve individuals. PMID:27525287

  8. An Unusual Ocular Emergency in Severe Dengue

    PubMed Central

    Nagaraj, Kalpana Badami; Jayadev, Chaitra; Yajmaan, Soumya; Prakash, Savitha

    2014-01-01

    Dengue, one of the most common mosquito-borne flavivirus diseases affecting humans, is spread by the Aedes aegypti mosquito. Most people infected with dengue virus are asymptomatic or only have mild symptoms such as an uncomplicated fever; few have more severe features, while in a small proportion it is life-threatening. Severe dengue is defined as that associated with severe bleeding, severe organ dysfunction, or severe plasma leakage. Ophthalmic manifestations can involve both the anterior and posterior segment. We report an ocular emergency of proptosis and globe rupture in a patient with severe dengue. PMID:25371643

  9. Anti-dengue efficacy of bioactive andrographolide from Andrographis paniculata (Lamiales: Acanthaceae) against the primary dengue vector Aedes aegypti (Diptera: Culicidae).

    PubMed

    Edwin, Edward-Sam; Vasantha-Srinivasan, Prabhakaran; Senthil-Nathan, Sengottayan; Thanigaivel, Annamalai; Ponsankar, Athirstam; Pradeepa, Venkatraman; Selin-Rani, Selvaraj; Kalaivani, Kandaswamy; Hunter, Wayne B; Abdel-Megeed, Ahmed; Duraipandiyan, Veeramuthu; Al-Dhabi, Naif Abdullah

    2016-11-01

    The current study investigated the toxic effect of the leaf extract compound andrographolide from Andrographis paniculata (Burm.f) against the dengue vector Ae. aegypti. GC-MS analysis revealed that andrographolide was recognized as the major chemical constituent with the prominent peak area compared with other compounds. All isolated toxic compounds were purified and confirmed through RP-HPLC against chemical standards. The larvicidal assays established at 25ppm of bioactive compound against the treated instars of Ae. Aegypti showed prominent mortality compared to other treated concentrations. The percent mortality of larvae was directly proportional to concentration. The lethal concentration (LC50) was observed at 12ppm treatment concentration. The bioactive andrographolide considerably reduced the detoxifying enzyme regulations of α- and β- carboxylesterases. In contrast, the levels of GST and CYP450 significantly increase in a dose dependent manner. The andrographolide also showed strong oviposition deterrence effects at the sub-lethal dose of 12ppm. Similarly, the mean number of eggs were also significantly reduced in a dose dependent manner. At the concentration of 12ppm the effective percentage of repellency was greater than 90% with a protection time of 15-210min, compared with control. The histopathology study displayed that larvae treated with bioactive andrographolide had cytopathic effects in the midgut epithelium compared with the control. The present study established that bioactive andrographolide served as a potential useful for dengue vector management. PMID:27443607

  10. Pushing the Envelope: Dengue Viral Membrane Coaxed into Shape by Molecular Simulations.

    PubMed

    Marzinek, Jan K; Holdbrook, Daniel A; Huber, Roland G; Verma, Chandra; Bond, Peter J

    2016-08-01

    Dengue virus is a flavivirus responsible for millions of infections per year. Its surface contains a phospholipid bilayer, within which are embedded the envelope (E) and membrane (M) proteins, arranged with icosahedral geometry. Exposure to low pH triggers the E proteins to undergo conformational changes, which precede fusion with the host cell membrane and release of the viral genome. The flavivirus membrane exhibits significant local curvature and deformation, as revealed by cryoelectron microscopy (cryo-EM), but its precise structure and interactions with envelope components remain unclear. We now report simulations of the dengue viral particle that refine its envelope structure in unprecedented detail. Our final models are morphologically consistent with cryo-EM data, and reveal the structural basis for membrane curvature. Electrostatic interactions increased envelope complex stability; this coupling has potential functional significance in the context of the viral fusion mechanism and infective states. PMID:27396828

  11. DenguePredict: An Integrated Drug Repositioning Approach towards Drug Discovery for Dengue

    PubMed Central

    Wang, QuanQiu; Xu, Rong

    2015-01-01

    Dengue is a viral disease of expanding global incidence without cures. Here we present a drug repositioning system (DenguePredict) leveraging upon a unique drug treatment database and vast amounts of disease- and drug-related data. We first constructed a large-scale genetic disease network with enriched dengue genetics data curated from biomedical literature. We applied a network-based ranking algorithm to find dengue-related diseases from the disease network. We then developed a novel algorithm to prioritize FDA-approved drugs from dengue-related diseases to treat dengue. When tested in a de-novo validation setting, DenguePredict found the only two drugs tested in clinical trials for treating dengue and ranked them highly: chloroquine ranked at top 0.96% and ivermectin at top 22.75%. We showed that drugs targeting immune systems and arachidonic acid metabolism-related apoptotic pathways might represent innovative drugs to treat dengue. In summary, DenguePredict, by combining comprehensive disease- and drug-related data and novel algorithms, may greatly facilitate drug discovery for dengue. PMID:26958268

  12. DENGUE PATIENTS AT PHOTHARAM HOSPITAL: A CLINICAL TRIAL SITE OF DENGUE VACCINE.

    PubMed

    Nunthanid, Somboon; Tiawilai, Anongrat

    2015-01-01

    Between 2005 and 2013, 1,868 dengue patients, 916 male and 952 female, were admitted to Photharam Hospital, Ratchaburi, Thailand. Among these patients, there were 1,209 with dengue fever (DF), 598 with dengue hemorrhagic fever (DHF), and 61 with dengue shock syndrome (DSS) with 1 death. The disease was seen all year round with a higher incidence in the rainy season. A trend of shift in age group towards older children and adults was seen during the study period. These data show that dengue patient admissions to Photharam Hospital are common, causing a heavy burden on the health system. Only one death was seen during the period of study, indicating that early recognition and effective management of dengue patients occurred. The trend towards higher age in dengue patients during the study period is a problem of concern and needs further clarification. PMID:26506727

  13. Spatial distribution of the risk of dengue and the entomological indicators in Sumaré, state of São Paulo, Brazil.

    PubMed

    Barbosa, Gerson Laurindo; Donalísio, Maria Rita; Stephan, Celso; Lourenço, Roberto Wagner; Andrade, Valmir Roberto; Arduino, Marylene de Brito; de Lima, Virgilia Luna Castor

    2014-05-01

    Dengue fever is a major public health problem worldwide, caused by any of four virus (DENV-1, DENV-2, DENV-3 and DENV-4; Flaviviridae: Flavivirus), transmitted by Aedes aegypti mosquito. Reducing the levels of infestation by A. aegypti is one of the few current strategies to control dengue fever. Entomological indicators are used by dengue national control program to measure the infestation of A. aegypti, but little is known about predictive power of these indicators to measure dengue risk. In this spatial case-control study, we analyzed the spatial distribution of the risk of dengue and the influence of entomological indicators of A. aegypti in its egg, larva-pupa and adult stages occurring in a mid-size city in the state of São Paulo. The dengue cases were those confirmed by the city's epidemiological surveillance system and the controls were obtained through random selection of points within the perimeter of the inhabited area. The values of the entomological indicators were extrapolated for the entire study area through the geostatistical ordinary kriging technique. For each case and control, the respective indicator values were obtained, according with its geographical coordinates and analyzed by using a generalized additive model. Dengue incidence demonstrated a seasonal behavior, as well as the entomological indicators of all mosquito's evolutionary stages. The infestation did not present a significant variation in intensity and was not a limiting or determining factor of the occurrence of cases in the municipality. The risk maps of the disease from crude and adjusted generalized additive models did not present differences, suggesting that areas with the highest values of entomological indicators were not associated with the incidence of dengue. The inclusion of other variables in the generalized additive models may reveal the modulatory effect for the risk of the disease, which is not found in this study. PMID:24831806

  14. Spatial Distribution of the Risk of Dengue and the Entomological Indicators in Sumaré, State of São Paulo, Brazil

    PubMed Central

    Barbosa, Gerson Laurindo; Donalísio, Maria Rita; Stephan, Celso; Lourenço, Roberto Wagner; Andrade, Valmir Roberto; Arduino, Marylene de Brito; de Lima, Virgilia Luna Castor

    2014-01-01

    Dengue fever is a major public health problem worldwide, caused by any of four virus (DENV-1, DENV-2, DENV-3 and DENV-4; Flaviviridae: Flavivirus), transmitted by Aedes aegypti mosquito. Reducing the levels of infestation by A. aegypti is one of the few current strategies to control dengue fever. Entomological indicators are used by dengue national control program to measure the infestation of A. aegypti, but little is known about predictive power of these indicators to measure dengue risk. In this spatial case-control study, we analyzed the spatial distribution of the risk of dengue and the influence of entomological indicators of A. aegypti in its egg, larva-pupa and adult stages occurring in a mid-size city in the state of São Paulo. The dengue cases were those confirmed by the city's epidemiological surveillance system and the controls were obtained through random selection of points within the perimeter of the inhabited area. The values of the entomological indicators were extrapolated for the entire study area through the geostatistical ordinary kriging technique. For each case and control, the respective indicator values were obtained, according with its geographical coordinates and analyzed by using a generalized additive model. Dengue incidence demonstrated a seasonal behavior, as well as the entomological indicators of all mosquito's evolutionary stages. The infestation did not present a significant variation in intensity and was not a limiting or determining factor of the occurrence of cases in the municipality. The risk maps of the disease from crude and adjusted generalized additive models did not present differences, suggesting that areas with the highest values of entomological indicators were not associated with the incidence of dengue. The inclusion of other variables in the generalized additive models may reveal the modulatory effect for the risk of the disease, which is not found in this study. PMID:24831806

  15. HPTLC analysis of Scoparia dulcis Linn (Scrophulariaceae) and its larvicidal potential against dengue vector Aedes aegypti.

    PubMed

    Wankhar, Wankupar; Srinivasan, Sakthivel; Rathinasamy, Sheeladevi

    2015-01-01

    This study evaluates the larvicidal activity of Scoparia dulcis aqueous extract against dengue vector and determines its major chemical components. The extract was tested at various concentrations ranging from 0.1 to 2 mg/mL against Aedes aegypti larvae. The extracts displayed significant larvicidal efficacy against Ae. aegypt species after 24 h exposure revealing LC50 of 3.3835 (mg/mL) and LC90 of 5.7578 (mg/mL). Finger printing profile carried out by CAMAG automatic TLC sample applicator programmed through WIN CATS software revealed peaks with different Rf values for three different volumes injected: 16, 15 and 18 peaks were spotted for 3, 6 and 9 μL, respectively. Ascending order of Rf values was also ascertained for each peak recorded. This study clearly signifies that S. dulcis extract contains numerous compounds that are known to have larvicidal properties which clearly substantiates its efficacy on Ae. aegypti larvae. PMID:25573588

  16. Urban epidemic of dengue virus serotype 3 infection, Senegal, 2009.

    PubMed

    Faye, Ousmane; Ba, Yamar; Faye, Oumar; Talla, Cheikh; Diallo, Diawo; Chen, Rubing; Mondo, Mireille; Ba, Rouguiétou; Macondo, Edgard; Siby, Tidiane; Weaver, Scott C; Diallo, Mawlouth; Sall, Amadou Alpha

    2014-03-01

    An urban epidemic of dengue in Senegal during 2009 affected 196 persons and included 5 cases of dengue hemorrhagic fever and 1 fatal case of dengue shock syndrome. Dengue virus serotype 3 was identified from all patients, and Aedes aegypti mosquitoes were identified as the primary vector of the virus. PMID:24572297

  17. Dengue related maculopathy and foveolitis.

    PubMed

    Juanarita, Jaafar; Azmi, Mohd Noor Raja; Azhany, Yaakub; Liza-Sharmini, Ahmad Tajudin

    2012-09-01

    A 24 year-old Malay lady presented with high grade fever, myalgia, generalized rashes, severe headache and was positive for dengue serology test. Her lowest platelet count was 45 × 10(9) cells/L. She complained of sudden onset of painlessness, profound loss of vision bilaterally 7 days after the onset of fever. On examination, her right eye best corrected vision was 6/30 and left eye was 6/120. Her anterior segment examination was unremarkable. Funduscopy revealed there were multiple retinal haemorrhages found at posterior pole of both fundi and elevation at fovea area with subretinal fluid. Systemic examination revealed normal findings except for residual petechial rashes. She was managed conservatively. Her vision improved tremendously after 2 months. The retinal hemorrhages and foveal elevation showed sign of resolving. Ocular manifestations following dengue fever is rare. However, bilateral visual loss can occur if both fovea are involved. PMID:23570008

  18. The Risk of Dengue Virus Transmission in Dar es Salaam, Tanzania during an Epidemic Period of 2014

    PubMed Central

    Mboera, Leonard E. G.; Mweya, Clement N.; Rumisha, Susan F.; Tungu, Patrick K.; Stanley, Grades; Makange, Mariam R.; Misinzo, Gerald; De Nardo, Pasquale; Vairo, Francesco; Oriyo, Ndekya M.

    2016-01-01

    Background In 2010, 2012, 2013 and 2014 dengue outbreaks have been reported in Dar es Salaam, Tanzania. However, there is no comprehensive data on the risk of transmission of dengue in the country. The objective of this study was to assess the risk of transmission of dengue in Dar es Salaam during the 2014 epidemic. Methodology/Principal Findings This cross-sectional study was conducted in Dar es Salaam, Tanzania during the dengue outbreak of 2014. The study involved Ilala, Kinondoni and Temeke districts. Adult mosquitoes were collected using carbon dioxide-propane powered Mosquito Magnet Liberty Plus traps. In each household compound, water-holding containers were examined for mosquito larvae and pupae. Dengue virus infection of mosquitoes was determined using real-time reverse transcription polymerase chain reaction (qRT-PCR). Partial amplification and sequencing of dengue virus genome in infected mosquitoes was performed. A total of 1,000 adult mosquitoes were collected. Over half (59.9%) of the adult mosquitoes were collected in Kinondoni. Aedes aegypti accounted for 17.2% of the mosquitoes of which 90.6% were from Kinondoni. Of a total of 796 houses inspected, 38.3% had water-holding containers in their premises. Kinondoni had the largest proportion of water-holding containers (57.7%), followed by Temeke (31.4%) and Ilala (23.4%). The most common breeding containers for the Aedes mosquitoes were discarded plastic containers and tires. High Aedes infestation indices were observed for all districts and sites, with a house index of 18.1% in Ilala, 25.5% in Temeke and 35.3% in Kinondoni. The respective container indices were 77.4%, 65.2% and 80.2%. Of the reared larvae and pupae, 5,250 adult mosquitoes emerged, of which 61.9% were Ae. aegypti. Overall, 27 (8.18) of the 330 pools of Ae. aegypti were positive for dengue virus. On average, the overall maximum likelihood estimate (MLE) indicates pooled infection rate of 8.49 per 1,000 mosquitoes (95%CI = 5.72–12

  19. Wolbachia versus dengue: Evolutionary forecasts.

    PubMed

    Bull, James J; Turelli, Michael

    2013-01-01

    A novel form of biological control is being applied to the dengue virus. The agent is the maternally transmitted bacterium Wolbachia, naturally absent from the main dengue vector, the mosquito Aedes aegypti. Three Wolbachia-based control strategies have been proposed. One is suppression of mosquito populations by large-scale releases of males incompatible with native females; this intervention requires ongoing releases. The other interventions transform wild mosquito populations with Wolbachia that spread via the frequency-dependent fitness advantage of Wolbachia-infected females; those interventions potentially require just a single, local release for area-wide disease control. One of these latter strategies uses Wolbachia that shortens mosquito life, indirectly preventing viral maturation/transmission. The other strategy uses Wolbachia that block viral transmission. All interventions can be undermined by viral, bacterial or mosquito evolution; viral virulence in humans may also evolve. We examine existing theory, experiments and comparative evidence to motivate predictions about evolutionary outcomes. (i) The life-shortening strategy seems the most likely to be thwarted by evolution. (ii) Mosquito suppression has a reasonable chance of working locally, at least in the short term, but long-term success over large areas is challenging. (iii) Dengue blocking faces strong selection for viral resistance but may well persist indefinitely at some level. Virulence evolution is not mathematically predictable, but comparative data provide no precedent for Wolbachia increasing dengue virulence. On balance, our analysis suggests that the considerable possible benefits of these technologies outweigh the known negatives, but the actual risk is largely unknown. PMID:24481199

  20. Novel, Meso-Substituted Cationic Porphyrin Molecule for Photo-Mediated Larval Control of the Dengue Vector Aedes aegypti

    PubMed Central

    Lucantoni, Leonardo; Magaraggia, Michela; Lupidi, Giulio; Ouedraogo, Robert Kossivi; Coppellotti, Olimpia; Esposito, Fulvio; Fabris, Clara; Jori, Giulio; Habluetzel, Annette

    2011-01-01

    Background Control of the mosquito vector population is the most effective strategy currently available for the prevention of dengue fever and the containment of outbreaks. Photo-activated oxidants may represent promising tools for developing effective, safe and ecofriendly novel larvicides. The purpose of this study was to evaluate the potential of the synthetic meso-substituted porphyrin meso-tri(N-methylpyridyl), meso-mono(N-tetradecylpyridyl)porphine (C14) as a photoactivatable larvicide against the dengue vector Aedes (Stegomyia) aegypti. Methodology The photophysical and photochemical properties of the C14 molecule were assessed spectrophotometrically. Photomediated larvicidal efficacy, route of intake and site of action were determined on Ae. aegypti larvae by laboratory bioassays and fluorescence microscopy. Using powdered food pellet for laboratory rodents (a common larval food used in the laboratory) as a carrier for C14, loading-release dynamics, larvicidal efficacy and residual activity of the C14-carrier complex were investigated. Main Findings The C14 molecule was found to exert a potent photosensitizing activity on Ae. aegypti larvae. At irradiation intervals of 12 h and 1 h, at a light intensity of 4.0 mW/cm2, which is 50–100 times lower than that of natural sunlight, LC50 values of 0.1 µM (0.15 mg/l) and 0.5 µM (0.77 mg/l) were obtained, respectively. The molecule was active after ingestion by the larvae and caused irreversible, lethal damage to the midgut and caecal epithelia. The amphiphilic nature of C14 allowed a formulate to be produced that not only was as active against the larvae as C14 in solution, but also possessed a residual activity of at least two weeks, in laboratory conditions. Conclusions The meso-substituted synthetic porphyrin C14, thanks to its photo-sensitizing properties represents an attractive candidate for the development of novel photolarvicides for dengue vector control. PMID:22206031

  1. Computer literature searches on dengue.

    PubMed Central

    Kuno, G.

    1993-01-01

    Many research workers, to save time, rely entirely on either on-line or off-line databases offered by an increasing number of information services. The characteristics of eight databases, including five on-line services, were analysed in the present study concerning the retrieval of information on dengue, the most important mosquito-borne viral disease of humans. Differences in the rate of retrieval among data-bases were apparent, depending on the main subject of publication as well as on the geographical location of the publisher. While rates of retrieval of references in molecular biology were generally satisfactory (mostly > 70%), those in clinical medicine and epidemiology were not (< 50%). The latter, as published in many dengue-endemic tropical countries, were found to be inadequately covered. For the global surveillance of dengue, which has increased in intensity and spread to many countries because of increased international travel, the development of a new database emphasizing tropical geographic medicine is highly desirable. PMID:8490978

  2. [Dengue fever in mainland France].

    PubMed

    Paty, M-C

    2014-11-01

    Dengue fever is the most widespread distributed vector borne viral disease. It is transmitted through the bites of Aedes aegypti and Aedes albopictus mosquitoes. With the expansion of Aedes albopictus and increasing travel exchange, it is no longer limited to the tropical zone and transmission has been documented in temperate areas. In mainland France, where Aedes albopictus has been present and disseminating since 2004, 2 episodes of autochthonous transmission occurred in 2010 and in 2013. Control measures against dengue and chikungunya, which shares the same vector, are implemented every year since 2006, in the areas where the vector is present. They aim at preventing or limiting local transmission of these diseases. They are based on epidemiological and entomological surveillance and vector control measures. The diagnosis of dengue, and chikungunya should be considered in case of suggestive symptoms in patients returning from an area of virus circulation. It should also be considered for patients living or having stayed in areas of mainland France where Aedes albopictus is present, during its activity period from May 1 to November 30. The prevention and control system, including vector control measures and the notification of cases to the local health authority should be known, as the risk of autochthonous transmission increases every year. PMID:25080833

  3. Recent Advances in Dengue: Relevance to Puerto Rico

    PubMed Central

    Noyd, David H.; Sharp, Tyler M.

    2015-01-01

    Dengue represents an increasingly important public health challenge in Puerto Rico, with recent epidemics in 2007, 2010, and 2012–2013. Although recent advances in dengue vaccine development offer hope for primary prevention, the role of health professionals in the diagnosis and management of dengue patients is paramount. Case definitions for dengue, dengue with warning signs, and severe dengue provide a framework to guide clinical decision-making. Furthermore, the differentiation between dengue and other acute febrile illnesses, such as leptospirosis and chikungunya, is necessary for the appropriate diagnosis and management of cases. An understanding of dengue epidemiology and surveillance in Puerto Rico provides context for clinicians in epidemic and non-epidemic periods. This review aims to improve health professionals’ ability to diagnose dengue, and as highlight the relevance of recent advances in dengue prevention and management in Puerto Rico. PMID:26061055

  4. Morbidity Rate Prediction of Dengue Hemorrhagic Fever (DHF) Using the Support Vector Machine and the Aedes aegypti Infection Rate in Similar Climates and Geographical Areas

    PubMed Central

    Kesorn, Kraisak; Ongruk, Phatsavee; Chompoosri, Jakkrawarn; Phumee, Atchara; Thavara, Usavadee; Tawatsin, Apiwat; Siriyasatien, Padet

    2015-01-01

    Background In the past few decades, several researchers have proposed highly accurate prediction models that have typically relied on climate parameters. However, climate factors can be unreliable and can lower the effectiveness of prediction when they are applied in locations where climate factors do not differ significantly. The purpose of this study was to improve a dengue surveillance system in areas with similar climate by exploiting the infection rate in the Aedes aegypti mosquito and using the support vector machine (SVM) technique for forecasting the dengue morbidity rate. Methods and Findings Areas with high incidence of dengue outbreaks in central Thailand were studied. The proposed framework consisted of the following three major parts: 1) data integration, 2) model construction, and 3) model evaluation. We discovered that the Ae. aegypti female and larvae mosquito infection rates were significantly positively associated with the morbidity rate. Thus, the increasing infection rate of female mosquitoes and larvae led to a higher number of dengue cases, and the prediction performance increased when those predictors were integrated into a predictive model. In this research, we applied the SVM with the radial basis function (RBF) kernel to forecast the high morbidity rate and take precautions to prevent the development of pervasive dengue epidemics. The experimental results showed that the introduced parameters significantly increased the prediction accuracy to 88.37% when used on the test set data, and these parameters led to the highest performance compared to state-of-the-art forecasting models. Conclusions The infection rates of the Ae. aegypti female mosquitoes and larvae improved the morbidity rate forecasting efficiency better than the climate parameters used in classical frameworks. We demonstrated that the SVM-R-based model has high generalization performance and obtained the highest prediction performance compared to classical models as measured by

  5. Convergent antibody signatures in human dengue.

    PubMed

    Parameswaran, Poornima; Liu, Yi; Roskin, Krishna M; Jackson, Katherine K L; Dixit, Vaishali P; Lee, Ji-Yeun; Artiles, Karen L; Zompi, Simona; Vargas, Maria José; Simen, Birgitte B; Hanczaruk, Bozena; McGowan, Kim R; Tariq, Muhammad A; Pourmand, Nader; Koller, Daphne; Balmaseda, Angel; Boyd, Scott D; Harris, Eva; Fire, Andrew Z

    2013-06-12

    Dengue is the most prevalent mosquito-borne viral disease in humans, and the lack of early prognostics, vaccines, and therapeutics contributes to immense disease burden. To identify patterns that could be used for sequence-based monitoring of the antibody response to dengue, we examined antibody heavy-chain gene rearrangements in longitudinal peripheral blood samples from 60 dengue patients. Comparing signatures between acute dengue, postrecovery, and healthy samples, we found increased expansion of B cell clones in acute dengue patients, with higher overall clonality in secondary infection. Additionally, we observed consistent antibody sequence features in acute dengue in the highly variable major antigen-binding determinant, complementarity-determining region 3 (CDR3), with specific CDR3 sequences highly enriched in acute samples compared to postrecovery, healthy, or non-dengue samples. Dengue thus provides a striking example of a human viral infection where convergent immune signatures can be identified in multiple individuals. Such signatures could facilitate surveillance of immunological memory in communities. PMID:23768493

  6. Dengue and Chikungunya Vector Control Pocket Guide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This technical guide consolidates information and procedures for surveillance and control of mosquitoes that transmit dengue and chikungunya viruses. The guide focuses on mosquitoes that transmit dengue but also makes reference to chikungunya and yellow fever because the pathogens that cause these ...

  7. Social justice, climate change, and dengue.

    PubMed

    Chang, Aileen Y; Fuller, Douglas O; Carrasquillo, Olveen; Beier, John C

    2014-01-01

    Climate change should be viewed fundamentally as an issue of global justice. Understanding the complex interplay of climatic and socioeconomic trends is imperative to protect human health and lessen the burden of diseases such as dengue fever. Dengue fever is rapidly expanding globally. Temperature, rainfall, and frequency of natural disasters, as well as non-climatic trends involving population growth and migration, urbanization, and international trade and travel, are expected to increase the prevalence of mosquito breeding sites, mosquito survival, the speed of mosquito reproduction, the speed of viral incubation, the distribution of dengue virus and its vectors, human migration patterns towards urban areas, and displacement after natural disasters. The burden of dengue disproportionately affects the poor due to increased environmental risk and decreased health care. Mobilization of social institutions is needed to improve the structural inequalities of poverty that predispose the poor to increased dengue fever infection and worse outcomes. This paper reviews the link between dengue and climatic factors as a starting point to developing a comprehensive understanding of how climate change affects dengue risk and how institutions can address the issues of social justice and dengue outbreaks that increasingly affect vulnerable urban populations. PMID:25474614

  8. Dengue fever: a Wikipedia clinical review.

    PubMed

    Heilman, James M; De Wolff, Jacob; Beards, Graham M; Basden, Brian J

    2014-01-01

    Dengue fever, also known as breakbone fever, is a mosquito-borne infectious tropical disease caused by the dengue virus. Symptoms include fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles. In a small proportion of cases, the disease develops into life-threatening dengue hemorrhagic fever, which results in bleeding, thrombocytopenia, and leakage of blood plasma, or into dengue shock syndrome, in which dangerously low blood pressure occurs. Treatment of acute dengue fever is supportive, with either oral or intravenous rehydration for mild or moderate disease and use of intravenous fluids and blood transfusion for more severe cases. Along with attempts to eliminate the mosquito vector, work is ongoing to develop a vaccine and medications targeted directly at the virus. PMID:25426178

  9. Dengue shock syndrome in an infant.

    PubMed

    Aurpibul, Linda; Khumlue, Punyawee; Issaranggoon na ayuthaya, Satja; Oberdorfer, Peninnah

    2014-01-01

    Dengue is a mosquito-borne infection affecting children and adults worldwide. In newborn infants, the dengue virus can cause diseases, especially in infants born to pregnant women hospitalised with dengue or postpartum women with fever. The authors report a case of a term newborn infant who presented with haemodynamic instability and thrombocytopaenia at the age of 7 days, without a history of clinical dengue infection in the mother. The physical examination revealed an afebrile and drowsy infant with a petechial rash all over the body and ecchymosis on both palms and soles. The authors confirmed the diagnosis using the dengue NS1 antigen on the first day of admission. The treatment included fluid management and platelet transfusion. The patient recovered well and was discharged from the hospital on the 10th day of hospitalisation. PMID:25073530

  10. Dissecting Japan's Dengue Outbreak in 2014

    PubMed Central

    Quam, Mikkel B.; Sessions, October; Kamaraj, Uma Sangumathi; Rocklöv, Joacim; Wilder-Smith, Annelies

    2016-01-01

    Despite Japan's temperate climate, a dengue outbreak occurred in Tokyo for the first time in over 70 years in 2014. We dissected this dengue outbreak based on phylogenetic analysis, travel interconnectivity, and environmental drivers for dengue epidemics. Comparing the available dengue virus 1 (DENV1) E gene sequence from this outbreak with 3,282 unique DENV1 sequences in National Center for Biotechnology Information suggested that the DENV might have been imported from China, Indonesia, Singapore, or Vietnam. With travelers arriving into Japan, Guangzhou (China) may have been the source of DENV introduction, given that Guangzhou also reported a large-scale dengue outbreak in 2014. Coinciding with the 2014 outbreak, Tokyo's climate conditions permitted the amplification of Aedes vectors and the annual peak of vectorial capacity. Given suitable vectors and climate conditions in addition to increasing interconnectivity with endemic areas of Asia, Tokyo's 2014 outbreak did not come as a surprise and may foretell more to come. PMID:26711518

  11. Risk factors in dengue shock syndrome.

    PubMed

    Thein, S; Aung, M M; Shwe, T N; Aye, M; Zaw, A; Aye, K; Aye, K M; Aaskov, J

    1997-05-01

    Despite a growing body of evidence predominantly, but not exclusively, from Thailand suggesting that the risk of developing dengue shock syndrome (DSS) is greatest following an anamnestic dengue infection, particularly if the most recent infection was with dengue 2 virus, there continues to be debate about the justification for these claims. This report describes a five-year, prospective study in two townships (suburbs) in Yangon (Rangoon) Myanmar (Burma) in which attempts were made to confirm the data from an earlier prospective study in Thailand and to address some of the criticism of earlier studies. This investigation found the incidence of anamnestic dengue infections in DSS patients to be significantly higher than in the community from which they were drawn and a significantly higher risk of developing DSS following an anamnestic infection (particularly with dengue 2 virus) than following a primary infection with any serotype. PMID:9180609

  12. Real-time forecasts of dengue epidemics

    NASA Astrophysics Data System (ADS)

    Yamana, T. K.; Shaman, J. L.

    2015-12-01

    Dengue is a mosquito-borne viral disease prevalent in the tropics and subtropics, with an estimated 2.5 billion people at risk of transmission. In many areas with endemic dengue, disease transmission is seasonal but prone to high inter-annual variability with occasional severe epidemics. Predicting and preparing for periods of higher than average transmission is a significant public health challenge. Here we present a model of dengue transmission and a framework for optimizing model simulations with real-time observational data of dengue cases and environmental variables in order to generate ensemble-based forecasts of the timing and severity of disease outbreaks. The model-inference system is validated using synthetic data and dengue outbreak records. Retrospective forecasts are generated for a number of locations and the accuracy of these forecasts is quantified.

  13. Dissecting Japan's Dengue Outbreak in 2014.

    PubMed

    Quam, Mikkel B; Sessions, October; Kamaraj, Uma Sangumathi; Rocklöv, Joacim; Wilder-Smith, Annelies

    2016-02-01

    Despite Japan's temperate climate, a dengue outbreak occurred in Tokyo for the first time in over 70 years in 2014. We dissected this dengue outbreak based on phylogenetic analysis, travel interconnectivity, and environmental drivers for dengue epidemics. Comparing the available dengue virus 1 (DENV1) E gene sequence from this outbreak with 3,282 unique DENV1 sequences in National Center for Biotechnology Information suggested that the DENV might have been imported from China, Indonesia, Singapore, or Vietnam. With travelers arriving into Japan, Guangzhou (China) may have been the source of DENV introduction, given that Guangzhou also reported a large-scale dengue outbreak in 2014. Coinciding with the 2014 outbreak, Tokyo's climate conditions permitted the amplification of Aedes vectors and the annual peak of vectorial capacity. Given suitable vectors and climate conditions in addition to increasing interconnectivity with endemic areas of Asia, Tokyo's 2014 outbreak did not come as a surprise and may foretell more to come. PMID:26711518

  14. Dengue shock syndrome in an infant

    PubMed Central

    Aurpibul, Linda; Khumlue, Punyawee; Issaranggoon na ayuthaya, Satja; Oberdorfer, Peninnah

    2014-01-01

    Dengue is a mosquito-borne infection affecting children and adults worldwide. In newborn infants, the dengue virus can cause diseases, especially in infants born to pregnant women hospitalised with dengue or postpartum women with fever. The authors report a case of a term newborn infant who presented with haemodynamic instability and thrombocytopaenia at the age of 7 days, without a history of clinical dengue infection in the mother. The physical examination revealed an afebrile and drowsy infant with a petechial rash all over the body and ecchymosis on both palms and soles. The authors confirmed the diagnosis using the dengue NS1 antigen on the first day of admission. The treatment included fluid management and platelet transfusion. The patient recovered well and was discharged from the hospital on the 10th day of hospitalisation. PMID:25073530

  15. Dengue fever, Hawaii, 2001-2002.

    PubMed

    Effler, Paul V; Pang, Lorrin; Kitsutani, Paul; Vorndam, Vance; Nakata, Michele; Ayers, Tracy; Elm, Joe; Tom, Tammy; Reiter, Paul; Rigau-Perez, José G; Hayes, John M; Mills, Kristin; Napier, Mike; Clark, Gary G; Gubler, Duane J

    2005-05-01

    Autochthonous dengue infections were last reported in Hawaii in 1944. In September 2001, the Hawaii Department of Health was notified of an unusual febrile illness in a resident with no travel history; dengue fever was confirmed. During the investigation, 1,644 persons with locally acquired denguelike illness were evaluated, and 122 (7%) laboratory-positive dengue infections were identified; dengue virus serotype 1 was isolated from 15 patients. No cases of dengue hemorrhagic fever or shock syndrome were reported. In 3 instances autochthonous infections were linked to a person who reported denguelike illness after travel to French Polynesia. Phylogenetic analyses showed the Hawaiian isolates were closely associated with contemporaneous isolates from Tahiti. Aedes albopictus was present in all communities surveyed on Oahu, Maui, Molokai, and Kauai; no Ae. aegypti were found. This outbreak underscores the importance of maintaining surveillance and control of potential disease vectors even in the absence of an imminent disease threat. PMID:15890132

  16. RNAi: antiviral therapy against dengue virus

    PubMed Central

    Idrees, Sobia; Ashfaq, Usman A

    2013-01-01

    Dengue virus infection has become a global threat affecting around 100 countries in the world. Currently, there is no licensed antiviral agent available against dengue. Thus, there is a strong need to develop therapeutic strategies that can tackle this life threatening disease. RNA interference is an important and effective gene silencing process which degrades targeted RNA by a sequence specific process. Several studies have been conducted during the last decade to evaluate the efficiency of siRNA in inhibiting dengue virus replication. This review summarizes siRNAs as a therapeutic approach against dengue virus serotypes and concludes that siRNAs against virus and host genes can be next generation treatment of dengue virus infection. PMID:23620845

  17. The use of Aedes aegypti larvae attractants to enhance the effectiveness of larvicides.

    PubMed

    Gonzalez, Paula V; Harburguer, Laura; González-Audino, Paola A; Masuh, Héctor M

    2016-06-01

    Aedes aegypti (L.) is an important dengue, chikungunya, and yellow fever vector. Immature stages of this species inhabit human-made containers placed in residential landscapes, and the application of larvicides inside containers that cannot be eliminated is still considered a priority in control programs. Larvicidal efficacy is influenced by several factors, including the formulation used, the water quality, and the susceptibility of larvae, among others. If an attractant can be incorporated into a slow-release larvicide formulation, it will be feasible to direct the larvae into the source of insecticide and thereby improving its efficacy. We studied the influence of 1-octen-3ol and 3-methylphenol on the rate of Ae. aegypti larvae mortality using the larvicides Bacillus thuringiensis var. israelensis (Bti), temephos, and spinosad. These chemicals were combined with the larvicides mixed with agar during the bioassays. Mortality was registered every 10 min, and a lethal time 50 (LT50) was calculated. The inclusion of the Ae. aegypti larvae attractants with the larvicides into a solid agar matrix improved their efficiency obtaining a strong and marked reduction in the LT50 compared with the use of larvicides alone. PMID:26922177

  18. Larvicidal Activity of Cassia occidentalis (Linn.) against the Larvae of Bancroftian Filariasis Vector Mosquito Culex quinquefasciatus

    PubMed Central

    Kumar, Deepak; Chawla, Rakesh; Dhamodaram, P.; Balakrishnan, N.

    2014-01-01

    Background & Objectives. The plan of this work was to study the larvicidal activity of Cassia occidentalis (Linn.) against the larvae of Culex quinquefasciatus. These larvae are the most significant vectors. They transmit the parasites and pathogens which cause a deadly disease like filariasis, dengue, yellow fever, malaria, Japanese encephalitis, chikungunya, and so forth, which are considered harmful towards the population in tropic and subtropical regions. Methods. The preliminary laboratory trail was undertaken to determine the efficacy of petroleum ether and N-butanol extract of dried whole plant of Cassia occidentalis (Linn.) belonging to the family Caesalpiniaceae at various concentrations against the late third instar larvae of Culex quinquefasciatus by following the WHO guidelines. Results. The results suggest that 100% mortality effect of petroleum ether and N-butanol extract of Cassia occidentalis (Linn.) was observed at 200 and 300 ppm (parts per million). The results obviously showed use of plants in insect control as an alternative method for minimizing the noxious effect of some pesticide compounds on the environment. Thus the extract of Cassia occidentalis (Linn.) is claimed as more selective and biodegradable agent. Conclusion. This study justified that plant Cassia occidentalis (Linn.) has a realistic mortality result for larvae of filarial vector. This is safe to individual and communities against mosquitoes. It is a natural weapon for mosquito control. PMID:24688786

  19. Metarhizium anisopliae pathogenesis of mosquito larvae: a verdict of accidental death.

    PubMed

    Butt, Tariq M; Greenfield, Bethany P J; Greig, Carolyn; Maffeis, Thierry G G; Taylor, James W D; Piasecka, Justyna; Dudley, Ed; Abdulla, Ahmed; Dubovskiy, Ivan M; Garrido-Jurado, Inmaculada; Quesada-Moraga, Enrique; Penny, Mark W; Eastwood, Daniel C

    2013-01-01

    Metarhizium anisopliae, a fungal pathogen of terrestrial arthropods, kills the aquatic larvae of Aedes aegypti, the vector of dengue and yellow fever. The fungus kills without adhering to the host cuticle. Ingested conidia also fail to germinate and are expelled in fecal pellets. This study investigates the mechanism by which this fungus adapted to terrestrial hosts kills aquatic mosquito larvae. Genes associated with the M. anisopliae early pathogenic response (proteinases Pr1 and Pr2, and adhesins, Mad1 and Mad2) are upregulated in the presence of larvae, but the established infection process observed in terrestrial hosts does not progress and insecticidal destruxins were not detected. Protease inhibitors reduce larval mortality indicating the importance of proteases in the host interaction. The Ae. aegypti immune response to M. anisopliae appears limited, whilst the oxidative stress response gene encoding for thiol peroxidase is upregulated. Cecropin and Hsp70 genes are downregulated as larval death occurs, and insect mortality appears to be linked to autolysis through caspase activity regulated by Hsp70 and inhibited, in infected larvae, by protease inhibitors. Evidence is presented that a traditional host-pathogen response does not occur as the species have not evolved to interact. M. anisopliae retains pre-formed pathogenic determinants which mediate host mortality, but unlike true aquatic fungal pathogens, does not recognise and colonise the larval host. PMID:24349111

  20. Metarhizium anisopliae Pathogenesis of Mosquito Larvae: A Verdict of Accidental Death

    PubMed Central

    Butt, Tariq M.; Greenfield, Bethany P. J.; Greig, Carolyn; Maffeis, Thierry G. G.; Taylor, James W. D.; Piasecka, Justyna; Dudley, Ed; Abdulla, Ahmed; Dubovskiy, Ivan M.; Garrido-Jurado, Inmaculada; Quesada-Moraga, Enrique; Penny, Mark W.; Eastwood, Daniel C.

    2013-01-01

    Metarhizium anisopliae, a fungal pathogen of terrestrial arthropods, kills the aquatic larvae of Aedes aegypti, the vector of dengue and yellow fever. The fungus kills without adhering to the host cuticle. Ingested conidia also fail to germinate and are expelled in fecal pellets. This study investigates the mechanism by which this fungus adapted to terrestrial hosts kills aquatic mosquito larvae. Genes associated with the M. anisopliae early pathogenic response (proteinases Pr1 and Pr2, and adhesins, Mad1 and Mad2) are upregulated in the presence of larvae, but the established infection process observed in terrestrial hosts does not progress and insecticidal destruxins were not detected. Protease inhibitors reduce larval mortality indicating the importance of proteases in the host interaction. The Ae. aegypti immune response to M. anisopliae appears limited, whilst the oxidative stress response gene encoding for thiol peroxidase is upregulated. Cecropin and Hsp70 genes are downregulated as larval death occurs, and insect mortality appears to be linked to autolysis through caspase activity regulated by Hsp70 and inhibited, in infected larvae, by protease inhibitors. Evidence is presented that a traditional host-pathogen response does not occur as the species have not evolved to interact. M. anisopliae retains pre-formed pathogenic determinants which mediate host mortality, but unlike true aquatic fungal pathogens, does not recognise and colonise the larval host. PMID:24349111

  1. QTL Mapping of Genome Regions Controlling Temephos Resistance in Larvae of the Mosquito Aedes aegypti

    PubMed Central

    Reyes-Solis, Guadalupe del Carmen; Saavedra-Rodriguez, Karla; Suarez, Adriana Flores; Black, William C.

    2014-01-01

    Introduction The mosquito Aedes aegypti is the principal vector of dengue and yellow fever flaviviruses. Temephos is an organophosphate insecticide used globally to suppress Ae. aegypti larval populations but resistance has evolved in many locations. Methodology/Principal Findings Quantitative Trait Loci (QTL) controlling temephos survival in Ae. aegypti larvae were mapped in a pair of F3 advanced intercross lines arising from temephos resistant parents from Solidaridad, México and temephos susceptible parents from Iquitos, Peru. Two sets of 200 F3 larvae were exposed to a discriminating dose of temephos and then dead larvae were collected and preserved for DNA isolation every two hours up to 16 hours. Larvae surviving longer than 16 hours were considered resistant. For QTL mapping, single nucleotide polymorphisms (SNPs) were identified at 23 single copy genes and 26 microsatellite loci of known physical positions in the Ae. aegypti genome. In both reciprocal crosses, Multiple Interval Mapping identified eleven QTL associated with time until death. In the Solidaridad×Iquitos (SLD×Iq) cross twelve were associated with survival but in the reciprocal IqxSLD cross, only six QTL were survival associated. Polymorphisms at acetylcholine esterase (AchE) loci 1 and 2 were not associated with either resistance phenotype suggesting that target site insensitivity is not an organophosphate resistance mechanism in this region of México. Conclusions/Significance Temephos resistance is under the control of many metabolic genes of small effect and dispersed throughout the Ae. aegypti genome. PMID:25330200

  2. Tree holes as larval habitats for Aedes aegypti in urban, suburban and forest habitats in a dengue affected area.

    PubMed

    Mangudo, C; Aparicio, J P; Gleiser, R M

    2015-12-01

    Aedes aegypti (L.) (Diptera: Culicidae), the main vector of dengue and urban yellow fever in the world, is highly adapted to the human environment. Artificial containers are the most common larval habitat for the species, but it may develop in tree holes and other phytotelmata. This study assessed whether tree holes in San Ramón de la Nueva Orán, a city located in subtropical montane moist forest where dengue outbreaks occur, are relevant as larval habitat for Ae. aegypti and if the species may be found in natural areas far from human habitations. Water holding tree holes were sampled during 3 years once a month along the rainy season using a siphon bottle, in urban and suburban sites within the city and in adjacent forested areas. Larvae and pupae were collected and the presence and volume of water in each tree hole were recorded. Finding Ae. aegypti in forested areas was an isolated event; however, the species was frequently collected from tree holes throughout the city and along the sampling period. Moreover, larvae were collected in considerably high numbers, stressing the importance of taking into account these natural cavities as potential reinfestation foci within dengue control framework. PMID:26193903

  3. Dengue virus serotyping based on envelope and membrane and nonstructural protein NS1 serotype-specific capture immunoglobulin M enzyme-linked immunosorbent assays.

    PubMed

    Shu, Pei-Yun; Chen, Li-Kuang; Chang, Shu-Fen; Su, Chien-Ling; Chien, Li-Jung; Chin, Chuan; Lin, Ting-Hsiang; Huang, Jyh-Hsiung

    2004-06-01

    Envelope and membrane (E/M) and nonstructural protein NS1 serotype-specific capture Immunoglobulin M (IgM) enzyme-linked immunosorbent assays (ELISAs) were developed to differentiate four dengue virus serotypes. A total of 93 anti-dengue virus IgM-positive serum samples collected between days 5 and 45 of illness from 59 confirmed dengue patients were analyzed. The results showed that positive serotype specificity could be identified for 86.1 and 47.6% of serum samples tested for E/M-specific IgM antibodies versus 83.3 and 42.9% of serum samples tested for NS1-specific IgM antibodies from patients with primary and secondary dengue virus infections, respectively. Dual analyses with both E/M and NS1 serotype-specific capture IgM ELISAs showed that positive serotype specificity could be correctly identified for 98.6 and 61.9% of all of the primary and secondary serum samples tested, respectively. These findings suggested that E/M and NS1 serotype-specific capture IgM ELISAs have the potential to be of use in dengue virus serotyping. PMID:15184425

  4. Dengue vector control and surveillance during a major outbreak in a coastal Red Sea area in Sudan.

    PubMed

    Seidahmed, O M E; Siam, H A M; Soghaier, M A; Abubakr, M; Osman, H A; Abd Elrhman, L S; Elmagbol, B; Velayudhan, R

    2012-12-01

    An unprecedented dengue outbreak occurred in 2010 in Port Sudan city, Sudan. Dengue incidence was 94 cases per 10 000 observed over 17 epidemiological weeks (total cases = 3 765). We report here the impact of the vector control response plan to the outbreak, which mainly entailed house inspection and insecticide space spraying. In total 3 048 houses were inspected during vector surveillance and 19 794 larvae and 3 240 pupae of Aedes aegypti were collected. Entomological indices decreased during the period: house index declined from 100% to 16% (F= 57.8, P < 0.001) and pupal/person (P/P) index from 0.77 to 0.10 (F= 3.06, P < 0.01) in weeks 9 and 21 respectively. This decline was accompanied by a decrease in cases from a peak of 341 cases in week 13 to zero in week 29 and the end of the outbreak. There was a significant correlation between the entomological parameters and dengue incidence (R2 = 0.83, F= 23.9, P < 0.001). Integrated epidemiological and vector surveillance is essential to an effective dengue control programme PMID:23301396

  5. Evaluation of a commercial dengue NS1 antigen-capture ELISA for laboratory diagnosis of acute dengue virus infection.

    PubMed

    Kumarasamy, V; Wahab, A H Abdul; Chua, S K; Hassan, Z; Chem, Y K; Mohamad, M; Chua, K B

    2007-03-01

    A commercial dengue NS1 antigen-capture ELISA was evaluated to demonstrate its potential application for early laboratory diagnosis of acute dengue virus infection. Dengue virus NS1 antigen was detected in 199 of 213 acute serum samples from patients with laboratory confirmation of acute dengue virus infection but none of the 354 healthy blood donors' serum specimens. The dengue NS1 antigen-capture ELISA gave an overall sensitivity of 93.4% (199/213) and a specificity of 100% (354/354). The sensitivity was significantly higher in acute primary dengue (97.3%) than in acute secondary dengue (70.0%). The positive predictive value of the dengue NS1 antigen-capture ELISA was 100% and negative predictive value was 97.3%. Comparatively, virus isolation gave an overall positive isolation rate of 68.1% with a positive isolation rate of 73.9 and 31.0% for acute primary dengue and acute secondary dengue, respectively. Molecular detection of dengue RNA by RT-PCR gave an overall positive detection rate of 66.7% with a detection rate of 65.2 and 75.9% for acute primary dengue and acute secondary dengue, respectively. The results indicate that the commercial dengue NS1 antigen-capture ELISA may be superior to virus isolation and RT-PCR for the laboratory diagnosis of acute dengue infection based on a single serum sample. PMID:17140671

  6. A recombinant, chimeric tetravalent dengue vaccine candidate based on a dengue virus serotype 2 backbone.

    PubMed

    Osorio, Jorge E; Wallace, Derek; Stinchcomb, Dan T

    2016-04-01

    Dengue fever is caused by infection with one of four dengue virus (DENV) serotypes (DENV-1-4), necessitating tetravalent dengue vaccines that can induce protection against all four DENV. Takeda's live attenuated tetravalent dengue vaccine candidate (TDV) comprises an attenuated DENV-2 strain plus chimeric viruses containing the prM and E genes of DENV-1, -3 and -4 cloned into the attenuated DENV-2 'backbone'. In Phase 1 and 2 studies, TDV was well tolerated by children and adults aged 1.5-45 years, irrespective of prior dengue exposure; mild injection-site symptoms were the most common adverse events. TDV induced neutralizing antibody responses and seroconversion to all four DENV as well as cross-reactive T cell-mediated responses that may be necessary for broad protection against dengue fever. PMID:26635182

  7. Evaluation of dengue NS1 test kits for the diagnosis of dengue fever.

    PubMed

    McBride, William John Hannan

    2009-05-01

    Detection of the dengue NS1 antigen during the symptomatic phase of illness represents an important advance in the diagnosis of dengue fever. The sensitivity of 2 commercial kits was evaluated in a panel of 91 serum samples collected at defined intervals after onset of symptomatic dengue fever. The sensitivity of the Bio-Rad Platelia (Bio-Rad Laboratories, Marnes-La-Coquette, France) dengue NS1 assay was 73.6% (95% confidence interval [CI], 63.7-81.6). The Panbio Early ELISA (Panbio Diagnostics, Brisbane, Australia) had a sensitivity of 63.7% (95% CI, 53.5-72.9). Four samples were equivocal in the Panbio assay. The sensitivity of both assays was highest on the 2nd to 4th day after illness onset and in primary dengue infections. Both assays will be useful for the detection of dengue viral infections early in the course of the infection, especially in nonendemic countries. PMID:19232865

  8. Myanmar dengue outbreak associated with displacement of serotypes 2, 3, and 4 by dengue 1.

    PubMed

    Thu, Hlaing Myat; Lowry, Kym; Myint, Thein Thein; Shwe, Than Nu; Han, Aye Maung; Khin, Kyu Kyu; Thant, Kyaw Zin; Thein, Soe; Aaskov, John

    2004-04-01

    In 2001, Myanmar (Burma) had its largest outbreak of dengue-15,361 reported cases of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), including 192 deaths. That year, 95% of dengue viruses isolated from patients were serotype 1 viruses belonging to two lineages that had diverged from an earlier, now extinct, lineage sometime before 1998. The ratio of DHF to DSS cases in 2001 was not significantly different from that in 2000, when 1,816 cases of DHF/DSS were reported and dengue 1 also was the most frequently isolated serotype. However, the 2001 ratio was significantly higher than that in 1998 (also an outbreak year) and in 1999, when all four serotypes were detected and serotypes 1, 2, and 3 were recovered in similar numbers. The large number of clinical cases in 2001 may have been due, in part, to a preponderance of infections with dengue 1 viruses. PMID:15200847

  9. Role of cognitive parameters in dengue hemorrhagic fever and dengue shock syndrome

    PubMed Central

    2013-01-01

    Dengue is becoming recognized as one of the most important vector-borne human diseases. It is predominant in tropical and subtropical zones but its geographical distribution is progressively expanding, making it an escalating global health problem of today. Dengue presents with spectrum of clinical manifestations, ranging from asymptomatic, undifferentiated mild fever, dengue fever (DF), to dengue hemorrhagic fever (DHF) with or without shock (DSS), a life-threatening illness characterized by plasma leakage due to increased vascular permeability. Currently, there are no antiviral modalities or vaccines available to treat and prevent dengue. Supportive care with close monitoring is the standard clinical practice. The mechanisms leading to DHF/DSS remains poorly understood. Multiple factors have been attributed to the pathological mechanism, but only a couple of these hypotheses are popular in scientific circles. The current discussion focuses on underappreciated factors, temperature, natural IgM, and endotoxin, which may be critical components playing roles in dengue pathogenesis. PMID:24305068

  10. Role of cognitive parameters in dengue hemorrhagic fever and dengue shock syndrome.

    PubMed

    Tsai, Jih-Jin; Chokephaibulkit, Kulkanya; Chen, Po-Chih; Liu, Li-Teh; Hsiao, Hui-Mien; Lo, Yu-Chih; Perng, Guey Chuen

    2013-01-01

    Dengue is becoming recognized as one of the most important vector-borne human diseases. It is predominant in tropical and subtropical zones but its geographical distribution is progressively expanding, making it an escalating global health problem of today. Dengue presents with spectrum of clinical manifestations, ranging from asymptomatic, undifferentiated mild fever, dengue fever (DF), to dengue hemorrhagic fever (DHF) with or without shock (DSS), a life-threatening illness characterized by plasma leakage due to increased vascular permeability. Currently, there are no antiviral modalities or vaccines available to treat and prevent dengue. Supportive care with close monitoring is the standard clinical practice. The mechanisms leading to DHF/DSS remains poorly understood. Multiple factors have been attributed to the pathological mechanism, but only a couple of these hypotheses are popular in scientific circles. The current discussion focuses on underappreciated factors, temperature, natural IgM, and endotoxin, which may be critical components playing roles in dengue pathogenesis. PMID:24305068

  11. Human antibody response to dengue virus: implications for dengue vaccine design.

    PubMed

    Moi, Meng Ling; Takasaki, Tomohiko; Kurane, Ichiro

    2016-01-01

    Dengue, a global health threat, is a leading cause of morbidity and mortality in most tropical and subtropical countries. Dengue can range from asymptomatic, relatively mild dengue fever to severe and life-threatening dengue hemorrhagic fever. Disease severity and outcome is largely associated with the host immune response. Several candidate vaccines in clinical trials appear promising as effective measures for dengue disease control. Vaccine development has been hampered by safety and efficacy issues, driven by a lack of understanding of the host immune response. This review focuses on recent research findings on the dengue host immune response, particularly in humans, and the relevance of these findings to challenges in vaccine development. PMID:27398060

  12. Sediment bioassays with oyster larvae

    SciTech Connect

    Chapman, P.M.; Morgan, J.D.

    1983-10-01

    Tests with naturally-occurring sediments are rare and sediment testing methodology is not standardized. The authors present a simple methodology for undertaking sediment bioassays with oyster larvae, and present data from a recent study to prove the utility of this method.

  13. [Emergence of dengue hemorrhagic fever in the Americas. Reemergence of dengue].

    PubMed

    Guzmán Tirado, M G; Kourí Flores, G; Bravo González, J R

    1999-01-01

    Dengue is at present the most important human arbovirosis. It is the main cause of hospitalization and death among children from southeast Asia. Two fifth of the world population live in dengue risk areas. In 1997, over 100 countries reported epidemic and more than 50,000,000 cases and 25,000 deaths were estomated. Nowadays, the Americas is passing through the same situation Asia faced years ago. In 1997, 27 countries reported cases of dengue, and in 14 of them cases of dengue hemorrhagic fever were documented. In all, 387,459 cases of classic dengue and 11,645 of dengue hemorrhagic fever were registered. During the last 2 decades dengue has increased significantly in our region with ups and downs in the annual incidence since 1981. It should be remarked that every 3 or 4 years there is a cyclic decrease and a further increase of the incidence, though it trends to rise. As regards dengue hemorrhagic fever, the situation is not more favorable. The Cuban epidemic that appeared in 1981 was completely untimely in the region. In 1989, 8 years later, the second important dengue hemorrhagic fever epidemic emerged in Venezuela, and from that moment on there has been an increasing tendency of this clinical form of the disease. The factors of the emergence and reemergence are present and rise year after year. The neoliberal policies and the consequent privatization of the health services in most of the countries allow us to watch a gloomy future in relation to the development of dengue and its severe form, the dengue hemorrhagic fever/dengue shock syndrome. PMID:10887549

  14. DengueTools: innovative tools and strategies for the surveillance and control of dengue

    PubMed Central

    Wilder-Smith, Annelies; Renhorn, Karl-Erik; Tissera, Hasitha; Abu Bakar, Sazaly; Alphey, Luke; Kittayapong, Pattamaporn; Lindsay, Steve; Logan, James; Hatz, Christoph; Reiter, Paul; Rocklöv, Joacim; Byass, Peter; Louis, Valérie R.; Tozan, Yesim; Massad, Eduardo; Tenorio, Antonio; Lagneau, Christophe; L'Ambert, Grégory; Brooks, David; Wegerdt, Johannah; Gubler, Duane

    2012-01-01

    Dengue fever is a mosquito-borne viral disease estimated to cause about 230 million infections worldwide every year, of which 25,000 are fatal. Global incidence has risen rapidly in recent decades with some 3.6 billion people, over half of the world's population, now at risk, mainly in urban centres of the tropics and subtropics. Demographic and societal changes, in particular urbanization, globalization, and increased international travel, are major contributors to the rise in incidence and geographic expansion of dengue infections. Major research gaps continue to hamper the control of dengue. The European Commission launched a call under the 7th Framework Programme with the title of ‘Comprehensive control of Dengue fever under changing climatic conditions’. Fourteen partners from several countries in Europe, Asia, and South America formed a consortium named ‘DengueTools’ to respond to the call to achieve better diagnosis, surveillance, prevention, and predictive models and improve our understanding of the spread of dengue to previously uninfected regions (including Europe) in the context of globalization and climate change. The consortium comprises 12 work packages to address a set of research questions in three areas: Research area 1: Develop a comprehensive early warning and surveillance system that has predictive capability for epidemic dengue and benefits from novel tools for laboratory diagnosis and vector monitoring. Research area 2: Develop novel strategies to prevent dengue in children. Research area 3: Understand and predict the risk of global spread of dengue, in particular the risk of introduction and establishment in Europe, within the context of parameters of vectorial capacity, global mobility, and climate change. In this paper, we report on the rationale and specific study objectives of ‘DengueTools’. DengueTools is funded under the Health theme of the Seventh Framework Programme of the European Community, Grant Agreement Number: 282589

  15. Economic burden of dengue infections in India.

    PubMed

    Garg, Pankaj; Nagpal, Jitender; Khairnar, Prakash; Seneviratne, Suranjith L

    2008-06-01

    Dengue infections are a significant cause of morbidity and mortality and lead to adverse economic effects in many developing tropical countries. In this study, we estimated the economic burden faced by India during the 2006 dengue epidemic. Costs incurred in managing a cohort of serologically confirmed dengue patients at a tertiary-level private hospital in north India were calculated. The median cost of treatment per hospitalised dengue patient was US$432.2 (95% CI US$343.6-625). A sensitivity analysis was performed to estimate the costs to the health system in India using a regression model. Variables with potentially large variations, including the ratio of unreported to reported cases and of hospitalised to ambulatory cases, the proportion requiring transfusions, loss of economic activities due to loss of workdays and deaths, were used. The average total economic burden was estimated to be US$27.4 million (95% CI US$25.7-29.1 million). Costs in the private heath sector were estimated to be almost four times public sector expenditures. Considerable economic losses (at a macro level) are incurred by developing countries like India during each dengue epidemic. Accurate estimates of the proportions of reported to unreported and of hospitalised to ambulatory dengue cases in India are needed to refine further the estimates of financial burden due to dengue in India. PMID:18402995

  16. Vaccines and immunization strategies for dengue prevention.

    PubMed

    Liu, Yang; Liu, Jianying; Cheng, Gong

    2016-01-01

    Dengue is currently the most significant arboviral disease afflicting tropical and sub-tropical countries worldwide. Dengue vaccines, such as the multivalent attenuated, chimeric, DNA and inactivated vaccines, have been developed to prevent dengue infection in humans, and they function predominantly by stimulating immune responses against the dengue virus (DENV) envelope (E) and nonstructural-1 proteins (NS1). Of these vaccines, a live attenuated chimeric tetravalent DENV vaccine developed by Sanofi Pasteur has been licensed in several countries. However, this vaccine renders only partial protection against the DENV2 infection and is associated with an unexplained increased incidence of hospitalization for severe dengue disease among children younger than nine years old. In addition to the virus-based vaccines, several mosquito-based dengue immunization strategies have been developed to interrupt the vector competence and effectively reduce the number of infected mosquito vectors, thus controlling the transmission of DENV in nature. Here we summarize the recent progress in the development of dengue vaccines and novel immunization strategies and propose some prospective vaccine strategies for disease prevention in the future. PMID:27436365

  17. How the pilidium larva feeds

    PubMed Central

    2013-01-01

    Introduction The nemertean pilidium is a long-lived feeding larva unique to the life cycle of a single monophyletic group, the Pilidiophora, which is characterized by this innovation. That the pilidium feeds on small planktonic unicells seems clear; how it does so is unknown and not readily inferred, because it shares little morphological similarity with other planktotrophic larvae. Results Using high-speed video of trapped lab-reared pilidia of Micrura alaskensis, we documented a multi-stage feeding mechanism. First, the external ciliation of the pilidium creates a swimming and feeding current which carries suspended prey past the primary ciliated band spanning the posterior margins of the larval body. Next, the larva detects prey that pass within reach, then conducts rapid and coordinated deformations of the larval body to re-direct passing cells and surrounding water into a vestibular space between the lappets, isolated from external currents but not quite inside the larva. Once a prey cell is thus captured, internal ciliary bands arranged within this vestibule prevent prey escape. Finally, captured cells are transported by currents within a buccal funnel toward the stomach entrance. Remarkably, we observed that the prey of choice – various cultured cryptomonads – attempt to escape their fate. Conclusions The feeding mechanism deployed by the pilidium larva coordinates local control of cilia-driven water transport with sensorimotor behavior, in a manner clearly distinct from any other well-studied larval feeding mechanisms. We hypothesize that the pilidium’s feeding strategy may be adapted to counter escape responses such as those deployed by cryptomonads, and speculate that similar needs may underlie convergences among disparate planktotrophic larval forms. PMID:23927417

  18. Workbook on the Identification of Mosquito Larvae.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; And Others

    This self-instructional booklet is designed to enable public health workers identify larvae of some important North American mosquito species. The morphological features of larvae of the various genera and species are illustrated in a programed booklet, which also contains illustrated taxonomic keys to the larvae of 11 North American genera and to…

  19. Bromeliad-inhabiting mosquitoes in an urban botanical garden of dengue endemic Rio de Janeiro. Are bromeliads productive habitats for the invasive vectors Aedes aegypti and Aedes albopictus?

    PubMed Central

    Mocellin, Márcio Goulart; Simões, Taynãna César; do Nascimento, Teresa Fernandes Silva; Teixeira, Maria Lucia França; Lounibos, Leon Philip; de Oliveira, Ricardo Lourenço

    2012-01-01

    Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus (0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats. PMID:20140379

  20. Dengue infection presenting as acute hypokalemic quadriparesis.

    PubMed

    Gupta, N; Garg, A; Chhabra, P

    2014-01-01

    Dengue infection is one of the most common viral hemorrhagic fevers seen in the tropical countries, including India. Its presentation varies from an acute self-resolving febrile illness to life-threatening hemorrhagic shock and multiorgan dysfunction leading to death. Neurological presentations are uncommon and limited to case reports only. Most common neurological manifestations being encephalitis, acute inflammatory demyelinating polyradiculoneuropathy, transverse myelitis, and acute disseminated encephalomyelitis.Hypokalemic quadriparesis as a presenting feature of dengue is extremely rare. Here, we report this case of a 33-year-old female, who presented with hypokalemic quadriparesis and was subsequently diagnosed as dengue infection. PMID:25121379

  1. [Imported dengue: an emerging arbovirosis in Spain].

    PubMed

    Ramos Geldres, T T; García López-Hortelano, M; Baquero-Artigao, F; Montero Vega, D; López Quintana, B; Mellado Peña, M J

    2015-01-01

    Dengue is caused by one of 4 serotypes of dengue virus. Only imported cases have been reported in Spain. The main clinical findings are fever and exanthema, although there may be severe forms, particularly in secondary infections. Five children with a primary, non severe dengue infection are presented. The diagnosis was based on clinical suspicion and epidemiological history, and confirmed by immunochromatography and ELISA tests. The outcome was favourable in all cases. It is important to consider this diagnosis in international travellers that present with fever within the 14 days of returning from an endemic area, in order to get an early diagnosis, adequate treatment and a good prognosis. PMID:24880817

  2. Issues Related to Recent Dengue Vaccine Development

    PubMed Central

    Konishi, Eiji

    2011-01-01

    Dengue fever (DF) and dengue hemorrhagic fever (DHF) are mosquito-transmitted diseases of global importance. Despite significant research efforts, no approved vaccines or antiviral drugs against these diseases are currently available. This brief article reviews the status of dengue vaccine development, with particular emphasis on the vaccine strategies in more advanced stages of evaluation; these include traditional attenuation, chimerization and engineered attenuation. Several aspects of these vaccine design strategies, including concerns about vaccine candidates inducing infection-enhancing antibodies, are also presented. PMID:22500138

  3. The use of rapid dengue diagnostic tests in a routine clinical setting in a dengue-endemic area of Colombia

    PubMed Central

    Osorio, Lyda; Uribe, Marcela; Ardila, Gloria Ines; Orejuela, Yaneth; Velasco, Margarita; Bonelo, Anilza; Parra, Beatriz

    2015-01-01

    There is insufficient evidence of the usefulness of dengue diagnostic tests under routine conditions. We sought to analyse how physicians are using dengue diagnostics to inform research and development. Subjects attending 14 health institutions in an endemic area of Colombia with either a clinical diagnosis of dengue or for whom a dengue test was ordered were included in the study. Patterns of test-use are described herein. Factors associated with the ordering of dengue diagnostic tests were identified using contingency tables, nonparametric tests and logistic regression. A total of 778 subjects were diagnosed with dengue by the treating physician, of whom 386 (49.5%) were tested for dengue. Another 491 dengue tests were ordered in subjects whose primary diagnosis was not dengue. Severe dengue classification [odds ratio (OR) 2.2; 95% confidence interval (CI) 1.1-4.5], emergency consultation (OR 1.9; 95% CI 1.4-2.5) and month of the year (OR 3.1; 95% CI 1.7-5.5) were independently associated with ordering of dengue tests. Dengue tests were used both to rule in and rule out diagnosis. The latter use is not justified by the sensitivity of current rapid dengue diagnostic tests. Ordering of dengue tests appear to depend on a combination of factors, including physician and institutional preferences, as well as other patient and epidemiological factors. PMID:25993399

  4. Dengue Expansion in Africa—Not Recognized or Not Happening?

    PubMed Central

    Junghanss, Thomas; Wills, Bridget; Brady, Oliver J.; Eckerle, Isabella; Farlow, Andrew; Hay, Simon I.; McCall, Philip J.; Messina, Jane P.; Ofula, Victor; Sall, Amadou A.; Sakuntabhai, Anavaj; Velayudhan, Raman; Wint, G.R. William; Zeller, Herve; Margolis, Harold S.; Sankoh, Osman

    2014-01-01

    An expert conference on Dengue in Africa was held in Accra, Ghana, in February 2013 to consider key questions regarding the possible expansion of dengue in Africa. Four key action points were highlighted to advance our understanding of the epidemiology of dengue in Africa. First, dengue diagnostic tools must be made more widely available in the healthcare setting in Africa. Second, representative data need to be collected across Africa to uncover the true burden of dengue. Third, established networks should collaborate to produce these types of data. Fourth, policy needs to be informed so the necessary steps can be taken to provide dengue vector control and health services. PMID:25271370

  5. Dengue expansion in Africa-not recognized or not happening?

    PubMed

    Jaenisch, Thomas; Junghanss, Thomas; Wills, Bridget; Brady, Oliver J; Eckerle, Isabella; Farlow, Andrew; Hay, Simon I; McCall, Philip J; Messina, Jane P; Ofula, Victor; Sall, Amadou A; Sakuntabhai, Anavaj; Velayudhan, Raman; Wint, G R William; Zeller, Herve; Margolis, Harold S; Sankoh, Osman

    2014-10-01

    An expert conference on Dengue in Africa was held in Accra, Ghana, in February 2013 to consider key questions regarding the possible expansion of dengue in Africa. Four key action points were highlighted to advance our understanding of the epidemiology of dengue in Africa. First, dengue diagnostic tools must be made more widely available in the healthcare setting in Africa. Second, representative data need to be collected across Africa to uncover the true burden of dengue. Third, established networks should collaborate to produce these types of data. Fourth, policy needs to be informed so the necessary steps can be taken to provide dengue vector control and health services. PMID:25271370

  6. Unusual Presentation of Dengue Fever Leading to Unnecessary Appendectomy

    PubMed Central

    Kumar, Lovekesh; Singh, Mahendra; Saxena, Ashish; Kolhe, Yuvraj; Karande, Snehal K.; Singh, Narendra; Venkatesh, P.; Meena, Rambabu

    2015-01-01

    Dengue fever is the most important arbovirus illness with an estimated incidence of 50–100 million cases per year. The common symptoms of dengue include fever, rash, malaise, nausea, vomiting, and musculoskeletal pain. Dengue fever may present as acute abdomen leading to diagnostic dilemma. The acute surgical complications of dengue fever include acute pancreatitis, acute acalculous cholecystitis, nonspecific peritonitis, and acute appendicitis. We report a case of dengue fever that mimicked acute appendicitis leading to unnecessary appendectomy. A careful history examination for dengue-related signs, and serial hemogram over the first 3-4 days of disease may prevent unnecessary appendectomy. PMID:26167314

  7. Unusual Presentation of Dengue Fever Leading to Unnecessary Appendectomy.

    PubMed

    Kumar, Lovekesh; Singh, Mahendra; Saxena, Ashish; Kolhe, Yuvraj; Karande, Snehal K; Singh, Narendra; Venkatesh, P; Meena, Rambabu

    2015-01-01

    Dengue fever is the most important arbovirus illness with an estimated incidence of 50-100 million cases per year. The common symptoms of dengue include fever, rash, malaise, nausea, vomiting, and musculoskeletal pain. Dengue fever may present as acute abdomen leading to diagnostic dilemma. The acute surgical complications of dengue fever include acute pancreatitis, acute acalculous cholecystitis, nonspecific peritonitis, and acute appendicitis. We report a case of dengue fever that mimicked acute appendicitis leading to unnecessary appendectomy. A careful history examination for dengue-related signs, and serial hemogram over the first 3-4 days of disease may prevent unnecessary appendectomy. PMID:26167314

  8. Cymbopogon citratus-synthesized gold nanoparticles boost the predation efficiency of copepod Mesocyclops aspericornis against malaria and dengue mosquitoes.

    PubMed

    Murugan, Kadarkarai; Benelli, Giovanni; Panneerselvam, Chellasamy; Subramaniam, Jayapal; Jeyalalitha, Tirupathi; Dinesh, Devakumar; Nicoletti, Marcello; Hwang, Jiang-Shiou; Suresh, Udaiyan; Madhiyazhagan, Pari

    2015-06-01

    Plant-borne compounds can be employed to synthesize mosquitocidal nanoparticles that are effective at low doses. However, how they affect the activity of mosquito predators in the aquatic environment is unknown. In this study, we synthesized gold nanoparticles (AuN) using the leaf extract of Cymbopogon citratus, which acted as a reducing and capping agent. AuN were characterized by a variety of biophysical methods and sorted for size in order to confirm structural integrity. C. citratus extract and biosynthesized AuN were tested against larvae and pupae of the malaria vector Anopheles stephensi and the dengue vector Aedes aegypti. LC₅₀ of C. citratus extract ranged from 219.32 ppm to 471.36 ppm. LC₅₀ of AuN ranged from 18.80 ppm to 41.52 ppm. In laboratory, the predatory efficiency of the cyclopoid crustacean Mesocyclops aspericornis against A. stephensi larvae was 26.8% (larva I) and 17% (larva II), while against A. aegypti was 56% (I) and 35.1% (II). Predation against late-instar larvae was minimal. In AuN-contaminated environment,predation efficiency against A. stephensi was 45.6% (I) and 26.7% (II), while against A. aegypti was 77.3% (I) and 51.6% (II). Overall, low doses of AuN may help to boost the control of Anopheles and Aedes larval populations in copepod-based control programs. PMID:25819295

  9. Dengue virus in Mexican bats

    PubMed Central

    AGUILAR-SETIÉN, Á.; ROMERO-ALMARAZ, M. L.; SÁNCHEZ-HERNÁNDEZ, C.; FIGUEROA, R.; JUÁREZ-PALMA, L. P.; GARCÍA-FLORES, M. M.; VÁZQUEZ-SALINAS, C.; SALAS-ROJAS, M.; HIDALGO-MARTÍNEZ, A. C.; PIERLÉ, S. AGUILAR; GARCÍA-ESTRADA, C.; RAMOS, C.

    2008-01-01

    SUMMARY Individuals belonging to five families, 12 genera, and 19 different species of bats from dengue endemic areas in the Gulf and Pacific coasts of Mexico were examined by ELISA, RT–PCR, and for the presence of dengue virus (DV) NS1 protein. Nine individuals from four species were seropositive by ELISA: three insectivorous, Myotis nigricans (four positives/12 examined), Pteronotus parnellii (3/19), and Natalus stramineus (1/4), and one frugivorous Artibeus jamaicensis (1/35) (12·86% seroprevalence in positive species). DV serotype 2 was detected by RT–PCR in four samples from three species (all from the Gulf coast – rainy season): two frugivorous, A. jamaicensis (2/9), and Carollia brevicauda (1/2), and one insectivorous, M. nigricans (1/11). The latter was simultaneously positive for NS1 protein. DV RT–PCR positive animals were all antibody seronegative. M. nigricans showed positive individuals for all three tests. This is the first evidence suggesting the presence of DV in bats from Mexico. PMID:18325131

  10. Protect Yourself and Your Baby from Dengue

    MedlinePlus

    ... prevent dengue virus infection during pregnancy » Use mosquito repellents with up to 50% DEET, picaridin, IR3535 or ... For babies over 2 months of age, use repellents with up to 30% DEET, picaridin or IR3535. ...

  11. Dengue: an update on treatment options.

    PubMed

    Chan, Candice Y Y; Ooi, Eng Eong

    2015-01-01

    Dengue is the most important mosquito-borne viral pathogen globally, with approximately 100 million cases of acute dengue annually. Infection can result in severe, life-threatening disease. Currently, there is no effective vaccine or licensed antiviral. Management is primarily supportive with fluids. Direct antiviral therapies that reduce dengue severity could be useful although these would need to inhibit all four viral serotypes effectively. This review focuses on the interventions that currently considered the gold standard in case management as well as exploratory therapies that have been studied in clinical trials. Although antiviral drug and therapeutic antibodies for dengue remain a work in progress, these studies have produced some promising results and may have the potential to be future drugs. PMID:26594048

  12. Dengue and its effects on liver

    PubMed Central

    Samanta, Jayanta; Sharma, Vishal

    2015-01-01

    Dengue has emerged as an important arboviral disease with significant impact on the disease burden in population residing in tropical countries. Dengue is spread by the bite of Aedes mosquito. The virus seems to have some hepatotoxic effects. Affliction of liver in form of derangements in the liver function tests is common and may include mild elevations in serum bilirubin, elevated transaminases and derangements in serum albumin. Although asymptomatic in most cases, clinical manifestations like jaundice, and acute liver failure (ALF) may occasionally complicate the clinical picture. Indeed, dengue has been implicated as an important cause of ALF in endemic countries. The present review focuses on the hepatic manifestations and the pathogenesis of the liver injury in dengue. PMID:25685758

  13. Treatment of cutaneous larva migrans.

    PubMed

    Caumes, E

    2000-05-01

    Cutaneous larva migrans caused by the larvae of animal hookworms is the most frequent skin disease among travelers returning from tropical countries. Complications (impetigo and allergic reactions), together with the intense pruritus and the significant duration of the disease, make treatment mandatory. Freezing the leading edge of the skin track rarely works. Topical treatment of the affected area with 10%-15% thiabendazole solution or ointment has limited value for multiple lesions and hookworm folliculitis, and requires applications 3 times a day for at least 15 days. Oral thiabendazole is poorly effective when given as a single dose (cure rate, 68%-84%) and is less well tolerated than either albendazole or ivermectin. Treatment with a single 400-mg oral dose of albendazole gives cure rates of 46%-100%; a single 12-mg oral dose of ivermectin gives cure rates of 81%-100%. PMID:10816151

  14. Seroprevalence of dengue virus antibodies in healthy Jamaicans.

    PubMed

    Brown, Michelle G; Vickers, Ivan E; Salas, Rose Alba; Smikle, Monica F

    2009-01-01

    Dengue fever, a mosquito borne viral infection, is endemic to Jamaica. The seroprevalence of dengue IgG and IgM antibodies were determined in 277 healthy Jamaicans by enzyme linked immunosorbent assay (ELISA). The seroprevalence of dengue IgG antibodies was 100% (277/277) while dengue IgM antibodies were found in 3.6% (10/277). A statistically significant association was found between the presence of dengue IgM antibodies and gender (males 10/105, 9.5% vs females 0/172, 0.0%); chi(2) = 17.0, p=0.000.The high seroprevalence rate of dengue IgG antibodies and the presence of dengue IgM in the healthy population are in keeping with the endemicity of the virus in Jamaica. Therefore tests for dengue IgG antibodies are of limited usefulness in Jamaica and can be safely excluded from diagnostic testing as a cost saving measure. Serological diagnosis of current dengue infection should be centred around the dengue IgM tests although the limitations in the predictive values of such tests should also be considered. The results also suggest that the risk of emergence of the more severe forms of dengue, dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS) in the Jamaican population, due to the presence of enhancing antibodies, is high. PMID:19996526

  15. Isolation of fourth-instars larva of Aedes (Finlaya) harveyi (Diptera: Culicidae) from the Nilgiri hills, Southern India.

    PubMed

    Bhuyan, Pranab Jyoti; Hiriyan, J; Nath, Anjan Jyoti

    2016-03-01

    During the post monsoon season of 2012, the ovitraps were employed for dengue vector surveillance nearer to human habitations in the Nilgiri hills of Southern India. All the eggs obtained were brought to laboratory, and reared individually to adult stage for identification. A total of 30 exuviae of fourth-instars larva specimen were identified as Aedes (Finlaya) harveyi which were compared to other closely related species. Though the adult male and female of Aedes (Finlaya) harveyi were recorded from some parts of India but so far the larval stage has not been recorded. PMID:27065629

  16. Behavioral Response of Aedes aegypti (Diptera: Culicidae) Larvae to Synthetic and Natural Attractants and Repellents.

    PubMed

    Gonzalez, Paula V; González Audino, Paola A; Masuh, Héctor M

    2015-11-01

    Aedes aegypti (L.) (Diptera: Culicidae) is the key vector of three important arboviral diseases: dengue, yellow fever, and chikungunya. Immature stages of this species inhabit human-made containers placed in residential landscapes. In this study, we evaluated a few compounds in a sensitive behavioral assay with Ae. aegypti larvae. The orientation of larvae to different compounds was surveyed using a performance index (PI). The PI represents the response to each odorant, where a value of +1 is indicative of full attraction and -1 represents complete repulsion. The widely used insect repellent N, N-diethyl-m-toluamide elicited a significantly negative PI, as did acetophenone and indole. A yeast extract, a known food source, elicited a significantly positive PI, as did 2-methylphenol, 1-octen-3-ol, 3-methylphenol, and fish food. On the other hand, no response was observed for the essential oil of Eucalyptus grandis x Eucalyptus camaldulensis at the concentration evaluated. Pretreatment of larvae with N-ethylmaleimide and ablation of the antennae resulted in a suppression of behavioral responses. The overall mobility of ablated larvae was indistinguishable from unablated controls, and absence of any visible locomotor dysfunction was observed. This work is a contribution to the study of the chemical ecology of disease vectors with the aim of developing more efficient tools for surveillance and control.Natural and synthetic compounds attractive to Ae. aegypti larvae should be incorporated into integrated pest management programs through the use of baited traps or by improving the efficacy of larvicides commonly used in control campaigns. PMID:26352935

  17. How the pilidium larva grows

    PubMed Central

    2014-01-01

    Background For animal cells, ciliation and mitosis appear to be mutually exclusive. While uniciliated cells can resorb their cilium to undergo mitosis, multiciliated cells apparently can never divide again. Nevertheless, many multiciliated epithelia in animals must grow or undergo renewal. The larval epidermis in a number of marine invertebrate larvae, such as those of annelids, mollusks and nemerteans, consists wholly or in part of multiciliated epithelial cells, generally organized into a swimming and feeding apparatus. Many of these larvae must grow substantially to reach metamorphosis. Do individual epithelial cells simply expand to accommodate an increase in body size, or are there dividing cells amongst them? If some cells divide, where are they located? Results We show that the nemertean pilidium larva, which is almost entirely composed of multiciliated cells, retains pockets of proliferative cells in certain regions of the body. Most of these are found near the larval ciliated band in the recesses between the larval lobes and lappets, which we refer to as axils. Cells in the axils contribute both to the growing larval body and to the imaginal discs that form the juvenile worm inside the pilidium. Conclusions Our findings not only explain how the almost-entirely multiciliated pilidium can grow, but also demonstrate direct coupling of larval and juvenile growth in a maximally-indirect life history. PMID:24690541

  18. Dengue vaccine development: strategies and challenges.

    PubMed

    Ramakrishnan, Lakshmy; Pillai, Madhavan Radhakrishna; Nair, Radhakrishnan R

    2015-03-01

    Infection with dengue virus may result in dengue fever or a more severe outcome, such as dengue hemorrhagic syndrome/shock. Dengue virus infection poses a threat to endemic regions for four reasons: the presence of four serotypes, each with the ability to cause a similar disease outcome, including fatality; difficulties related to vector control; the lack of specific treatment; and the nonavailability of a suitable vaccine. Vaccine development is considered challenging due to the severity of the disease observed in individuals who have acquired dengue-specific immunity, either passively or actively. Therefore, the presence of vaccine-induced immunity against a particular serotype may prime an individual to severe disease on exposure to dengue virus. Vaccine development strategies include live attenuated vaccines, chimeric, DNA-based, subunit, and inactivated vaccines. Each of the candidates is in various stages of preclinical and clinical development. Issues pertaining to selection pressures, viral interaction, and safety still need to be evaluated in order to induce a complete protective immune response against all four serotypes. This review highlights the various strategies that have been employed in vaccine development, and identifies the obstacles to producing a safe and effective vaccine. PMID:25494228

  19. [Neonatal Dengue. Presentation of clinical cases].

    PubMed

    Romero-Santacruz, Edith; Lira-Canul, Janeth Jaqueline; Pacheco-Tugores, Fredy; Palma-Chan, Adolfo Gonzalo

    2015-05-01

    Dengue is an infectious disease caused by a flavivirus, with four serotypes, transmitted by the mosquito Aedes aegypti. In Mexico it is a public health problem, especially in the region of central and southeast of the country. The disease can be asymptomatic or present serious forms and even death. It is confirmed by detection of the NS1 Antigen; IgM antibodies, polymerase chain reaction and virus isolation. The vertical transmission to de newborn has been little studied. 7 cases in neonates from November to December 2011 are reported. All patients were male, obtained by caesarean section between 34 and 40 weeks of gestation, whose mothers were enrolled with fever and symptoms associated with dengue disease and serology positive for dengue. Six with positive AgNS1 and one positive IgM; one mother died. All the newborns had positive serology for dengue, 4 with positive AgNS1 and 3 positive IgM. The clinical features of the newborn ranged from asymptomatic to one serious dengue fever, shock and hemorrhage. The symptomatic 6 attended with thrombocytopenia, changes in temperature and unspecific disturbance. The severity of mothers conditioned disrepair product at birth, but not with subsequent gravity of the new born. Vertical trasmission of dengue should be suspected in risk areas, to maintain vigilance and to give early treatment. Also is neccesary promote the realization of specific diagnostic and therapeutic guidelines to the neonatal period. PMID:26233977

  20. International Dengue Vaccine Communication and Advocacy: Challenges and Way Forward.

    PubMed

    Carvalho, Ana; Van Roy, Rebecca; Andrus, Jon

    2016-01-01

    Dengue vaccine introduction will likely occur soon. However, little has been published on international dengue vaccine communication and advocacy. More effort at the international level is required to review, unify and strategically disseminate dengue vaccine knowledge to endemic countries' decision makers and potential donors. Waiting to plan for the introduction of new vaccines until licensure may delay access in developing countries. Concerted efforts to communicate and advocate for vaccines prior to licensure are likely challenged by unknowns of the use of dengue vaccines and the disease, including uncertainties of vaccine impact, vaccine access and dengue's complex pathogenesis and epidemiology. Nevertheless, the international community has the opportunity to apply previous best practices for vaccine communication and advocacy. The following key strategies will strengthen international dengue vaccine communication and advocacy: consolidating existing coalitions under one strategic umbrella, urgently convening stakeholders to formulate the roadmap for integrated dengue prevention and control, and improving the dissemination of dengue scientific knowledge. PMID:26855170

  1. Estimating dengue vector abundance in the wet and dry season: implications for targeted vector control in urban and peri-urban Asia

    PubMed Central

    Wai, Khin Thet; Arunachalam, Natarajan; Tana, Susilowati; Espino, Fe; Kittayapong, Pattamaporn; Abeyewickreme, W; Hapangama, Dilini; Tyagi, Brij Kishore; Htun, Pe Than; Koyadun, Surachart; Kroeger, Axel; Sommerfeld, Johannes; Petzold, Max

    2012-01-01

    Background Research has shown that the classical Stegomyia indices (or “larval indices”) of the dengue vector Aedes aegypti reflect the absence or presence of the vector but do not provide accurate measures of adult mosquito density. In contrast, pupal indices as collected in pupal productivity surveys are a much better proxy indicator for adult vector abundance. However, it is unknown when it is most optimal to conduct pupal productivity surveys, in the wet or in the dry season or in both, to inform control services about the most productive water container types and if this pattern varies among different ecological settings. Methods A multi-country study in randomly selected twelve to twenty urban and peri-urban neighborhoods (“clusters”) of six Asian countries, in which all water holding containers were examined for larvae and pupae of Aedes aegypti during the dry season and the wet season and their productivity was characterized by water container types. In addition, meteorological data and information on reported dengue cases were collected. Findings The study reconfirmed the association between rainfall and dengue cases (“dengue season”) and underlined the importance of determining through pupal productivity surveys the “most productive containers types”, responsible for the majority (>70%) of adult dengue vectors. The variety of productive container types was greater during the wet than during the dry season, but included practically all container types productive in the dry season. Container types producing pupae were usually different from those infested by larvae indicating that containers with larval infestations do not necessarily foster pupal development and thus the production of adult Aedes mosquitoes. Conclusion Pupal productivity surveys conducted during the wet season will identify almost all of the most productive container types for both the dry and wet seasons and will therefore facilitate cost-effective targeted interventions

  2. Distribution of Mosquito Larvae on Kosrae Island, Kosrae State, the Federated States of Micronesia

    PubMed Central

    Noda, Shinichi; Yamamoto, Sota; Toma, Takako; Taulung, Livinson

    2013-01-01

    Surveys of mosquito larvae were carried out in six areas of Kosrae Island, Kosrae State, the Federated States of Micronesia in December 2009 and June 2012. A total of 962 larvae of six species were collected from 106 natural and artificial habitats. They were identified as Aedes aegypti, Ae. albopictus, Ae. marshallensis, Culex quinquefasciatus, Cx. annulirostris, and Cx. kusaiensis. This is the first report from Kosrae Island for three of these species—Ae. marshallensis, Cx. quinquefasciatus, and Cx. annulirostris. The most abundant species was Ae. albopictus, followed by Ae. marshallensis, and these two species were found in all areas. Relatively large numbers of Cx. quinquefasciatus and Cx. kusaiensis were found in five areas. Fewer Cx. annulirostris were found, and only in three areas. Aedes aegypti larvae were collected from a single habitat at Tafunsak in 2009. To prevent the outbreak of dengue fever, environmental management should focus on the destruction, alteration, disposal and recycling of containers that produce larger numbers of adult Aedes mosquitoes. PMID:24478593

  3. Distribution of mosquito larvae on kosrae island, kosrae state, the federated States of micronesia.

    PubMed

    Noda, Shinichi; Yamamoto, Sota; Toma, Takako; Taulung, Livinson

    2013-12-01

    Surveys of mosquito larvae were carried out in six areas of Kosrae Island, Kosrae State, the Federated States of Micronesia in December 2009 and June 2012. A total of 962 larvae of six species were collected from 106 natural and artificial habitats. They were identified as Aedes aegypti, Ae. albopictus, Ae. marshallensis, Culex quinquefasciatus, Cx. annulirostris, and Cx. kusaiensis. This is the first report from Kosrae Island for three of these species-Ae. marshallensis, Cx. quinquefasciatus, and Cx. annulirostris. The most abundant species was Ae. albopictus, followed by Ae. marshallensis, and these two species were found in all areas. Relatively large numbers of Cx. quinquefasciatus and Cx. kusaiensis were found in five areas. Fewer Cx. annulirostris were found, and only in three areas. Aedes aegypti larvae were collected from a single habitat at Tafunsak in 2009. To prevent the outbreak of dengue fever, environmental management should focus on the destruction, alteration, disposal and recycling of containers that produce larger numbers of adult Aedes mosquitoes. PMID:24478593

  4. Symptomatic Dengue Disease in Five Southeast Asian Countries: Epidemiological Evidence from a Dengue Vaccine Trial

    PubMed Central

    Taurel, Anne-Frieda; Capeding, Maria Rosario; Tran, Ngoc Huu; Hadinegoro, Sri Rezeki; Chotpitayasunondh, Tawee; Chong, Chee Kheong; Wartel, T. Anh; Beucher, Sophie; Frago, Carina; Moureau, Annick; Simmerman, Mark; Laot, Thelma; L’Azou, Maïna; Bouckenooghe, Alain

    2016-01-01

    Dengue incidence has increased globally, but empirical burden estimates are scarce. Prospective methods are best-able to capture all severities of disease. CYD14 was an observer-blinded dengue vaccine study conducted in children 2–14 years of age in Indonesia, Malaysia, Thailand, the Philippines, and Vietnam. The control group received no vaccine and resembled a prospective, observational study. We calculated the rates of dengue according to different laboratory or clinical criteria to make inferences about dengue burden, and compared with rates reported in the passive surveillance systems to calculate expansion factors which describe under-reporting. Over 6,933 person-years of observation in the control group there were 319 virologically confirmed dengue cases, a crude attack rate of 4.6%/year. Of these, 92 cases (28.8%) were clinically diagnosed as dengue fever or dengue hemorrhagic fever by investigators and 227 were not, indicating that most symptomatic disease fails to satisfy existing case definitions. When examining different case definitions, there was an inverse relationship between clinical severity and observed incidence rates. CYD14’s active surveillance system captured a greater proportion of symptomatic dengue than national passive surveillance systems, giving rise to expansion factors ranging from 0.5 to 31.7. This analysis showed substantial, unpredictable and variable under-reporting of symptomatic dengue, even within a controlled clinical trial environment, and emphasizes that burden estimates are highly sensitive to case definitions. These data will assist in generating disease burden estimates and have important policy implications when considering the introduction and health economics of dengue prevention and control interventions. PMID:27532617

  5. Symptomatic Dengue Disease in Five Southeast Asian Countries: Epidemiological Evidence from a Dengue Vaccine Trial.

    PubMed

    Nealon, Joshua; Taurel, Anne-Frieda; Capeding, Maria Rosario; Tran, Ngoc Huu; Hadinegoro, Sri Rezeki; Chotpitayasunondh, Tawee; Chong, Chee Kheong; Wartel, T Anh; Beucher, Sophie; Frago, Carina; Moureau, Annick; Simmerman, Mark; Laot, Thelma; L'Azou, Maïna; Bouckenooghe, Alain

    2016-08-01

    Dengue incidence has increased globally, but empirical burden estimates are scarce. Prospective methods are best-able to capture all severities of disease. CYD14 was an observer-blinded dengue vaccine study conducted in children 2-14 years of age in Indonesia, Malaysia, Thailand, the Philippines, and Vietnam. The control group received no vaccine and resembled a prospective, observational study. We calculated the rates of dengue according to different laboratory or clinical criteria to make inferences about dengue burden, and compared with rates reported in the passive surveillance systems to calculate expansion factors which describe under-reporting. Over 6,933 person-years of observation in the control group there were 319 virologically confirmed dengue cases, a crude attack rate of 4.6%/year. Of these, 92 cases (28.8%) were clinically diagnosed as dengue fever or dengue hemorrhagic fever by investigators and 227 were not, indicating that most symptomatic disease fails to satisfy existing case definitions. When examining different case definitions, there was an inverse relationship between clinical severity and observed incidence rates. CYD14's active surveillance system captured a greater proportion of symptomatic dengue than national passive surveillance systems, giving rise to expansion factors ranging from 0.5 to 31.7. This analysis showed substantial, unpredictable and variable under-reporting of symptomatic dengue, even within a controlled clinical trial environment, and emphasizes that burden estimates are highly sensitive to case definitions. These data will assist in generating disease burden estimates and have important policy implications when considering the introduction and health economics of dengue prevention and control interventions. PMID:27532617

  6. Stochastic dynamics of dengue epidemics

    NASA Astrophysics Data System (ADS)

    de Souza, David R.; Tomé, Tânia; Pinho, Suani T. R.; Barreto, Florisneide R.; de Oliveira, Mário J.

    2013-01-01

    We use a stochastic Markovian dynamics approach to describe the spreading of vector-transmitted diseases, such as dengue, and the threshold of the disease. The coexistence space is composed of two structures representing the human and mosquito populations. The human population follows a susceptible-infected-recovered (SIR) type dynamics and the mosquito population follows a susceptible-infected-susceptible (SIS) type dynamics. The human infection is caused by infected mosquitoes and vice versa, so that the SIS and SIR dynamics are interconnected. We develop a truncation scheme to solve the evolution equations from which we get the threshold of the disease and the reproductive ratio. The threshold of the disease is also obtained by performing numerical simulations. We found that for certain values of the infection rates the spreading of the disease is impossible, for any death rate of infected mosquitoes.

  7. Unusual Presentation of Dengue Fever

    PubMed Central

    Aslam, Moaz; Aleem, Numra A.; Zahid, Mohammad F.; Rahman, Arshalooz J.

    2016-01-01

    Dengue fever (DF) is an acute febrile illness that follows a self-limiting course. However, some patients suffer from complications, including myocarditis, due to the involvement of other organs. A child presented at the Aga Khan University Hospital in Karachi, Pakistan, in June 2013 with a high-grade fever, malaise and epigastric pain radiating to the chest. Positive DF antigen and immunoglobulin M assays confirmed the diagnosis of DF. Persistent bradycardia with low blood pressure led to further cardiac investigations which showed a decreased ejection fraction and raised serum cardiac enzymes, indicating myocardial damage. With supportive care and use of inotropes, the spontaneous normalisation of cardiac enzyme levels and ejection fraction was observed. The child was discharged five days after admission. This case highlights the importance of identifying myocarditis in DF patients suffering from cardiac symptoms that are not explained by other potential aetiologies. Awareness, early suspicion and supportive care are essential to ensure favourable outcomes. PMID:26909198

  8. Pathogenesis of dengue virus diseases: missing pieces in the jigsaw.

    PubMed

    Bielefeldt-Ohmann, H

    1997-10-01

    The mechanisms involved in the pathogenesis of dengue hemorrhagic fever and dengue shock syndrome remain unresolved. Antibody-dependent enhancement of infection has long been thought to play a central role; however, this remains unverified. The alternative hypothesis that virus variation, virulence and dynamics may account for severe dengue disease, particularly in children, should be considered. PMID:9351178

  9. Clinical differences among PCR-proven dengue serotype infections.

    PubMed

    Limkittikul, Kriengsak; Yingsakmongkon, Sangchai; Jittmittraphap, Akanitt; Chuananon, Somchai; Kongphrai, Yuphin; Kowasupathr, Surasak; Rojanawatsirivit, Chaiyaporn; Mammen, Mammen P; Jampangern, Wipawee

    2005-11-01

    The objective of this study was to compare the clinical spectra of the dengue serotypes proven by the PCR technique. This retrospective study reviewed the clinical information of dengue-infected patients who were admitted to northeastern provincial hospitals in Thailand from June to September 2002. Dengue infection and viral serotypes were confirmed by polymerase chain reaction (PCR). Paired anti-dengue immunoglobulin G (IgG) and IgM from paired sera were analyzed by enzyme-linked immunosorbent assay (ELISA). Ninety-nine PCR-proven dengue-infected Thai patients were studied. Their ages ranged from 3-30 years. They were infected with DEN1, DEN2, DEN3 and DEN4 in 21, 55, 12, and 12%, respectively. Twenty-two percent had primary and 78% had secondary infections. Dengue fever was the most common presentation for both primary (77.2%) and secondary infections (46.7%). The ratios of dengue fever:dengue hemorrhagic fever (DF:DHF) and non-dengue shock syndrome:dengue shock syndrome (non-DSS:DSS) for DEN2 was the lowest of the dengue serotypes. There was no difference in the duration of fever, percentage of hepatomegaly and bleeding among the serotypes in both DF and DHF. The trends in the white blood cells, lymphocyte and atypical lymphocyte counts in DEN3 were the highest, while those of DEN1 were the lowest of the dengue serotypes. PMID:16610645

  10. Upward trend in dengue incidence among hospitalized patients, United States.

    PubMed

    Streit, Judy A; Yang, Ming; Cavanaugh, Joseph E; Polgreen, Philip M

    2011-05-01

    International travel and a global expansion of dengue fever have the potential to increase the incidence of dengue in the United States. We conducted a retrospective cohort analysis of trends in dengue among hospitalized patients by using the National Inpatient Sample (2000-2007); the number of cases more than tripled (p<0.0001). PMID:21529411

  11. Seroprevalence of acute dengue in a Malaysian tertiary medical centre

    PubMed Central

    Ding, Chuan Hun; Rashid, Zetti Zainol; Rahman, Md. Mostafizur; Khang, NanFeng; Low, Wan Ngor; Hussin, Nurabrar; Marzuki, Melissa Iqlima; Jaafar, Alyaa Nadhira; Roslan, Nurul Ain’ Nabilla; Chandrasekaran, Terukumar

    2016-01-01

    Objectives: The aims of this study were to determine the seroprevalence of acute dengue in Universiti Kebangsaan Malaysia (UKM) Medical Centre and its correlation with selected haematological and biochemical parameters. Methods: This cross-sectional study was conducted from January to June 2015. A patient was serologically diagnosed with acute dengue if the dengue virus IgG, IgM or NS-1 antigen was reactive. Results: Out of 1,774 patients suspected to have acute dengue, 1,153 were serologically diagnosed with the infection, resulting in a seroprevalence of 64.9%. Dengue-positive patients had a lower mean platelet count (89 × 109/L) compared to the dengue-negative patients (171 × 109/L) (p<0.0001). The mean total white cell count was also lower in the dengue-positive cases (4.7 × 109/L vs. 7.2 × 109/L; p<0.0001). The mean haematocrit was higher in patients with acute dengue (42.5% vs. 40.0%; p<0.0001). Likewise, the serum alanine transaminase level was also higher in patients with acute dengue (108 U/L vs. 54 U/L; p<0.0001). Conclusions: Dengue is very prevalent in UKM Medical Centre as most patients suspected to have acute dengue had serological evidence of the infection. The platelet count was the single most likely parameter to be abnormal (i.e. low) in patients with acute dengue. PMID:27182269

  12. Describing dengue epidemics: Insights from simple mechanistic models

    NASA Astrophysics Data System (ADS)

    Aguiar, Maíra; Stollenwerk, Nico; Kooi, Bob W.

    2012-09-01

    We present a set of nested models to be applied to dengue fever epidemiology. We perform a qualitative study in order to show how much complexity we really need to add into epidemiological models to be able to describe the fluctuations observed in empirical dengue hemorrhagic fever incidence data offering a promising perspective on inference of parameter values from dengue case notifications.

  13. Breeding Sites of Aedes aegypti: Potential Dengue Vectors in Dire Dawa, East Ethiopia.

    PubMed

    Getachew, Dejene; Tekie, Habte; Gebre-Michael, Teshome; Balkew, Meshesha; Mesfin, Akalu

    2015-01-01

    Background and Objectives. Entomological survey was carried out from May-June to September-October 2014 to investigate the presence of dengue vectors in discarded tires and artificial water containers in houses and peridomestic areas. Methods. A cross-sectional immature stage survey was done indoors and outdoors in 301 houses. Mosquito larval sampling was conducted using pipette or dipper depending on container types. Larvae were identified morphologically and larval indices were also calculated. Results. A total of 750 containers were inspected, and of these 405 were positive for mosquito larvae. A total of 1,873 larvae were collected and morphologically identified as Aedes aegypti (n = 1580: 84.4%) and Culex (n = 293: 15.6%). The larval indices, house index, container index, and breteau index, varied from 33.3 to 86.2, from 23.2 to 73.9, and from 56.5 to 188.9, respectively. Conclusion. Aedes aegypti is breeding in a wide range of artificial containers. To control these mosquitoes, the integration of different methods should be taken into consideration. PMID:26435712

  14. Breeding Sites of Aedes aegypti: Potential Dengue Vectors in Dire Dawa, East Ethiopia

    PubMed Central

    Getachew, Dejene; Tekie, Habte; Gebre-Michael, Teshome; Balkew, Meshesha; Mesfin, Akalu

    2015-01-01

    Background and Objectives. Entomological survey was carried out from May-June to September-October 2014 to investigate the presence of dengue vectors in discarded tires and artificial water containers in houses and peridomestic areas. Methods. A cross-sectional immature stage survey was done indoors and outdoors in 301 houses. Mosquito larval sampling was conducted using pipette or dipper depending on container types. Larvae were identified morphologically and larval indices were also calculated. Results. A total of 750 containers were inspected, and of these 405 were positive for mosquito larvae. A total of 1,873 larvae were collected and morphologically identified as Aedes aegypti (n = 1580: 84.4%) and Culex (n = 293: 15.6%). The larval indices, house index, container index, and breteau index, varied from 33.3 to 86.2, from 23.2 to 73.9, and from 56.5 to 188.9, respectively. Conclusion. Aedes aegypti is breeding in a wide range of artificial containers. To control these mosquitoes, the integration of different methods should be taken into consideration. PMID:26435712

  15. Oral Ingestion of Transgenic RIDL Ae. aegypti Larvae Has No Negative Effect on Two Predator Toxorhynchites Species

    PubMed Central

    Nordin, Oreenaiza; Donald, Wesley; Ming, Wong Hong; Ney, Teoh Guat; Mohamed, Khairul Asuad; Halim, Nor Azlina Abdul; Winskill, Peter; Hadi, Azahari Abdul; Muhammad, Zulkamal Safi'in; Lacroix, Renaud; Scaife, Sarah; McKemey, Andrew Robert; Beech, Camilla; Shahnaz, Murad; Alphey, Luke; Nimmo, Derric David; Nazni, Wasi Ahmed; Lee, Han Lim

    2013-01-01

    Dengue is the most important mosquito-borne viral disease. No specific treatment or vaccine is currently available; traditional vector control methods can rarely achieve adequate control. Recently, the RIDL (Release of Insect carrying Dominant Lethality) approach has been developed, based on the sterile insect technique, in which genetically engineered ‘sterile’ homozygous RIDL male insects are released to mate wild females; the offspring inherit a copy of the RIDL construct and die. A RIDL strain of the dengue mosquito, Aedes aegypti, OX513A, expresses a fluorescent marker gene for identification (DsRed2) and a protein (tTAV) that causes the offspring to die. We examined whether these proteins could adversely affect predators that may feed on the insect. Aedes aegypti is a peri-domestic mosquito that typically breeds in small, rain-water-filled containers and has no specific predators. Toxorhynchites larvae feed on small aquatic organisms and are easily reared in the laboratory where they can be fed exclusively on mosquito larvae. To evaluate the effect of a predator feeding on a diet of RIDL insects, OX513A Ae. aegypti larvae were fed to two different species of Toxorhynchites (Tx. splendens and Tx. amboinensis) and effects on life table parameters of all life stages were compared to being fed on wild type larvae. No significant negative effect was observed on any life table parameter studied; this outcome and the benign nature of the expressed proteins (tTAV and DsRed2) indicate that Ae. aegypti OX513A RIDL strain is unlikely to have any adverse effects on predators in the environment. PMID:23527029

  16. Biology of Paenibacillus larvae, a deadly pathogen of honey bee larvae.

    PubMed

    Ebeling, Julia; Knispel, Henriette; Hertlein, Gillian; Fünfhaus, Anne; Genersch, Elke

    2016-09-01

    The gram-positive bacterium Paenibacillus larvae is the etiological agent of American Foulbrood of honey bees, a notifiable disease in many countries. Hence, P. larvae can be considered as an entomopathogen of considerable relevance in veterinary medicine. P. larvae is a highly specialized pathogen with only one established host, the honey bee larva. No other natural environment supporting germination and proliferation of P. larvae is known. Over the last decade, tremendous progress in the understanding of P. larvae and its interactions with honey bee larvae at a molecular level has been made. In this review, we will present the recent highlights and developments in P. larvae research and discuss the impact of some of the findings in a broader context to demonstrate what we can learn from studying "exotic" pathogens. PMID:27394713

  17. Dengue-induced Acute Kidney Injury (DAKI): A Neglected and Fatal Complication of Dengue Viral Infection--A Systematic Review.

    PubMed

    Mallhi, Tauqeer Hussain; Sarriff, Azmi; Adnan, Azreen Syazril; Khan, Yusra Habib; Hamzah, Azhar Amir; Jummaat, Fauziah; Khan, Amer Hayat

    2015-11-01

    Dengue Viral Infection (DVI) imperils an estimated 2.5 billion people living in tropical and subtropical regions. World Health Organization (2011) guidelines also classified dengue as 'Expanded Dengue Syndrome' to incorporate wide spectrum of unusual manifestations of dengue infection affecting various organ systems - including liver, kidney, heart and brain. Renal involvements are least appreciated area of dengue infection, therefore, we systematically reviewed studies describing renal disorders in dengue infection, with emphasis on Acute Kidney Injury (AKI). The purpose of current review is to underscore clinicians’attention to this neglected intricacy of DVI. It suggests that dengue induced renal involvements vary from glomerulonephritis, nephrotic range proteinuria and AKI. We observed great disparity in incidence of AKI among dengue patients, based upon criteria used to define AKI. AKI among dengue patients was found to be associated with significant morbidity, mortality and longer hospitalization, adding financial burden to patients and healthcare system. Additionally, we identified several predictors of AKI in dengue patients including old age, obesity, severe dengue infection and concurrent bacterial or viral infection. Direct viral injury and deposition of antigen-antibody complex in glomerulus were found to be possible causes of renal disorders in dengue infection. Prior knowledge of clinico-laboratory characteristics and risk factors with early detection of AKI by using appropriate criteria would not only reduce morbidity and mortality but also decrease burden to patients and healthcare system. PMID:26577971

  18. Taste processing in Drosophila larvae

    PubMed Central

    Apostolopoulou, Anthi A.; Rist, Anna; Thum, Andreas S.

    2015-01-01

    The sense of taste allows animals to detect chemical substances in their environment to initiate appropriate behaviors: to find food or a mate, to avoid hostile environments and predators. Drosophila larvae are a promising model organism to study gustation. Their simple nervous system triggers stereotypic behavioral responses, and the coding of taste can be studied by genetic tools at the single cell level. This review briefly summarizes recent progress on how taste information is sensed and processed by larval cephalic and pharyngeal sense organs. The focus lies on several studies, which revealed cellular and molecular mechanisms required to process sugar, salt, and bitter substances. PMID:26528147

  19. Single stimulus learning in zebrafish larvae.

    PubMed

    O'Neale, Ashley; Ellis, Joseph; Creton, Robbert; Colwill, Ruth M

    2014-02-01

    Learning about a moving visual stimulus was examined in zebrafish larvae using an automated imaging system and a t1-t2 design. In three experiments, zebrafish larvae were exposed to one of two inputs at t1 (either a gray bouncing disk or an identical but stationary disk) followed by a common test at t2 (the gray bouncing disk). Using 7days post-fertilization (dpf) larvae and 12 stimulus exposures, Experiment 1 established that these different treatments produced differential responding to the moving disk during testing. Larvae familiar with the moving test stimulus were significantly less likely to be still in its presence than larvae that had been exposed to the identical but stationary stimulus. Experiment 2 confirmed this result in 7dpf larvae and extended the finding to 5 and 6dpf larvae. Experiment 3 found differential responding to the moving test stimulus with 4 or 8 stimulus exposures but not with just one exposure in 7dpf larvae. These results provide evidence for learning in very young zebrafish larvae. The merits and challenges of the t1-t2 framework to study learning are discussed. PMID:24012906

  20. Spatial and Temporal Patterns of Dengue Transmission along a Red Sea Coastline: A Longitudinal Entomological and Serological Survey in Port Sudan City

    PubMed Central

    Seidahmed, Osama M. E.; Hassan, Safa A.; Soghaier, Mohamed A.; Siam, Hanna A. M.; Ahmed, Fayez T. A.; Elkarsany, Mubarak M.; Sulaiman, Suad M.

    2012-01-01

    Background Dengue is an emerging health problem in several coastlines along the Red Sea. The objective of the present work is to elucidate spatial and temporal patterns of dengue transmission in Port Sudan. Methods/Findings A longitudinal study with three cross-sectional surveys was carried out in upper, middle and lower class neighborhoods, from November 2008 to October 2009. Monthly, entomological surveys were followed by serological surveys in dengue vector-positive houses. Meteorological records were obtained from two weather stations in the city during the same time. Overall, 2825 houses were inspected. Aedes aegypti represented 65% (35,714/54,944) and 68% (2526/3715) of the collected larvae and pupae, respectively. Out of 4640 drinking water containers, 2297 were positive for Ae. aegypti. Clay-pots “Zeirr” followed by plastic barrels were key productive containers for pupae of dengue vector, 63% (n = 3959) and 26% (n = 1651), respectively. A total of 791 blood samples were tested using PanBio Capture/Indirect IgM ELISA. Overall, the sero-prevalence rate of dengue ranged between 3%–8% (41/791), compared to an incidence of 29–40 new cases per 10,000 (193/54886) in the same examined population. Lower and middle class neighborhoods had higher entomological indices compared with upper class ones (p<0.001). Although, dengue incidence rate was significantly lower in the middle and lower class neighborhoods (F = 73.97, d.f. = 2, p<0.001), no difference in IgM prevalence was shown. The city is subject to two transmission peaks in the winter (i.e. November–January), and summer (i.e. June–August). The serological peaks of dengue are preceded by entomological peaks that occur before the onset of winter (November) and summer (March) respectively. Conclusion Dengue incidence is heterogeneously distributed across the neighborhoods of Port Sudan and exhibits a bi-cyclic intra-annual pattern. Hence, it should be feasible to carry out timely vector

  1. Epidemiology of dengue: past, present and future prospects.

    PubMed

    Murray, Natasha Evelyn Anne; Quam, Mikkel B; Wilder-Smith, Annelies

    2013-01-01

    Dengue is currently regarded globally as the most important mosquito-borne viral disease. A history of symptoms compatible with dengue can be traced back to the Chin Dynasty of 265-420 AD. The virus and its vectors have now become widely distributed throughout tropical and subtropical regions of the world, particularly over the last half-century. Significant geographic expansion has been coupled with rapid increases in incident cases, epidemics, and hyperendemicity, leading to the more severe forms of dengue. Transmission of dengue is now present in every World Health Organization (WHO) region of the world and more than 125 countries are known to be dengue endemic. The true impact of dengue globally is difficult to ascertain due to factors such as inadequate disease surveillance, misdiagnosis, and low levels of reporting. Currently available data likely grossly underestimates the social, economic, and disease burden. Estimates of the global incidence of dengue infections per year have ranged between 50 million and 200 million; however, recent estimates using cartographic approaches suggest this number is closer to almost 400 million. The expansion of dengue is expected to increase due to factors such as the modern dynamics of climate change, globalization, travel, trade, socioeconomics, settlement and also viral evolution. No vaccine or specific antiviral therapy currently exists to address the growing threat of dengue. Prompt case detection and appropriate clinical management can reduce the mortality from severe dengue. Effective vector control is the mainstay of dengue prevention and control. Surveillance and improved reporting of dengue cases is also essential to gauge the true global situation as indicated in the objectives of the WHO Global Strategy for Dengue Prevention and Control, 2012-2020. More accurate data will inform the prioritization of research, health policy, and financial resources toward reducing this poorly controlled disease. The objective of

  2. Dengue in an area of the Colombian Caribbean

    PubMed Central

    Rodríguez-Barreto, Heidi; Mattar-Velilla, Salim

    2015-01-01

    Background: In Colombia, dengue is an endemic disease and the four serotypes have been reported. Objective: To describe the frequency and severity of dengue in an area of the Colombian Caribbean (Department of Cordoba) Methods: A retrospective study was conducted. Two data sources were analysed: The database from the Direction of Health in Córdoba, and clinical registers of patients diagnosed with haemorrhagic fevers and fevers of unknown origin in reference hospitals. Results: The mean incidence of dengue between 2003-2010 was 36.5 cases/105 inhabitants (CI95%: 34.3-37.5) and adjusted for sub-reporting, could be between 178.5 and 521.6. The mean incidence of severe dengue was 4.7 cases/105 inhabitants (CI95%: 4.3-5.0). Mean mortality rate due to dengue was 0.3 cases/105 inhabitants. The fatality rate was below 1%. The mean total leukocyte count in patients with dengue was 6,181 mm3 (CI95%: 5,973-6,389) and with severe Dengue was 4,729 mm3 (CI95%: 4,220-5,238). The average platelet count in patients with Dengue was 118,793/mm3 (CI95%: 107,255-130,331) and in patients with Severe Dengue 77,655 (CI95%: 59,640-95,670). Both differences were statistically significant (p <0.05). The frequency of laboratories test per patient in patients with Dengue and severe Dengue were different. Conclusion: The department of Cordoba is a highly endemic zone of Dengue and severe Dengue in the Colombian Caribbean. Moreover, the results show significant differences between dengue and severe dengue so much in tests as in frequency of use of healthcare services. PMID:26019378

  3. Reduction in dengue cases observed during mass control of Aedes (Stegomyia) in street catch basins in an endemic urban area in Colombia

    PubMed Central

    Ocampo, Clara B.; Mina, Neila Julieth; Carabalí, Mabel; Alexander, Neal; Osorio, Lyda

    2015-01-01

    Dengue incidence continues to increase globally and, in the absence of an efficacious vaccine, prevention strategies are limited to vector control. It has been suggested that targeting the most productive breeding sites instead of all water-holding containers could be a cost-effective vector control strategy. We sought to identify and continuously control the most productive Aedes (Stegomyia) breeding site in an endemic urban area in Colombia and followed the subsequent incidence of dengue. In the urban area of Guadalajara de Buga, southwestern Colombia, potential breeding sites inside and outside houses were first characterized, and local personnel trained to assess their productivity based on the pupae/person index. Simultaneously, training and monitoring were implemented to improve the dengue case surveillance system. Entomological data and insecticide resistance studies were used to define the targeted intervention. Then, a quasi-experimental design was used to assess the efficacy of the intervention in terms of the positivity index of the targeted and non- targeted breeding sites, and the impact on dengue cases. Street catch basins (storm drains) were the potential breeding site most frequently found containing Aedes immature stages in the baseline (58.3% of 108). Due to the high resistance to temephos (0% mortality after 24 h), the intervention consisted of monthly application of pyriproxyfen in all the street catch basins (n = 4800). A significant decrease in catch basins positivity for Aedes larvae was observed after each monthly treatment (p < 0.001). Over the intervention period, a reduction in the dengue incidence in Buga was observed (rate ratio 0.19, 95% CI 0.12–0.30, p < 0.0001) after adjusting for autocorrelation and controlling with a neighboring town, Palmira, This study highlights the importance of street catch basins as Aedes breeding sites and suggests that their targeted control could help to decrease dengue transmission in such areas. PMID

  4. Reduction in dengue cases observed during mass control of Aedes (Stegomyia) in street catch basins in an endemic urban area in Colombia.

    PubMed

    Ocampo, Clara B; Mina, Neila Julieth; Carabalí, Mabel; Alexander, Neal; Osorio, Lyda

    2014-04-01

    Dengue incidence continues to increase globally and, in the absence of an efficacious vaccine, prevention strategies are limited to vector control. It has been suggested that targeting the most productive breeding sites instead of all water-holding containers could be a cost-effective vector control strategy. We sought to identify and continuously control the most productive Aedes (Stegomyia) breeding site in an endemic urban area in Colombia and followed the subsequent incidence of dengue. In the urban area of Guadalajara de Buga, southwestern Colombia, potential breeding sites inside and outside houses were first characterized, and local personnel trained to assess their productivity based on the pupae/person index. Simultaneously, training and monitoring were implemented to improve the dengue case surveillance system. Entomological data and insecticide resistance studies were used to define the targeted intervention. Then, a quasi-experimental design was used to assess the efficacy of the intervention in terms of the positivity index of the targeted and non- targeted breeding sites, and the impact on dengue cases. Street catch basins (storm drains) were the potential breeding site most frequently found containing Aedes immature stages in the baseline (58.3% of 108). Due to the high resistance to temephos (0% mortality after 24h), the intervention consisted of monthly application of pyriproxyfen in all the street catch basins (n=4800). A significant decrease in catch basins positivity for Aedes larvae was observed after each monthly treatment (p<0.001). Over the intervention period, a reduction in the dengue incidence in Buga was observed (rate ratio 0.19, 95% CI 0.12-0.30, p<0.0001) after adjusting for autocorrelation and controlling with a neighboring town, Palmira, This study highlights the importance of street catch basins as Aedes breeding sites and suggests that their targeted control could help to decrease dengue transmission in such areas. PMID:24388794

  5. Green-synthesized silver nanoparticles as a novel control tool against dengue virus (DEN-2) and its primary vector Aedes aegypti.

    PubMed

    Sujitha, Vasu; Murugan, Kadarkarai; Paulpandi, Manickam; Panneerselvam, Chellasamy; Suresh, Udaiyan; Roni, Mathath; Nicoletti, Marcello; Higuchi, Akon; Madhiyazhagan, Pari; Subramaniam, Jayapal; Dinesh, Devakumar; Vadivalagan, Chithravel; Chandramohan, Balamurugan; Alarfaj, Abdullah A; Munusamy, Murugan A; Barnard, Donald R; Benelli, Giovanni

    2015-09-01

    Dengue is an arthropod-borne viral infection mainly vectored through the bite of Aedes mosquitoes. Recently, its transmission has strongly increased in urban and semi-urban areas of tropical and sub-tropical regions worldwide, becoming a major international public health concern. There is no specific treatment for dengue. Its prevention and control solely depends on effective vector control measures. In this study, we proposed the green-synthesis of silver nanoparticles (AgNP) as a novel and effective tool against the dengue serotype DEN-2 and its major vector Aedes aegypti. AgNP were synthesized using the Moringa oleifera seed extract as reducing and stabilizing agent. AgNP were characterized using a variety of biophysical methods including UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and sorted for size categories. AgNP showed in vitro antiviral activity against DEN-2 infecting vero cells. Viral titer was 7 log10 TCID50/ml in control (AgNP-free), while it dropped to 3.2 log10 TCID50/ml after a single treatment with 20 μl/ml of AgNP. After 6 h, DEN-2 yield was 5.8 log10 PFU/ml in the control, while it was 1.4 log10 PFU/ml post-treatment with AgNP (20 μl/ml). AgNP were highly effective against the dengue vector A. aegypti, with LC50 values ranging from 10.24 ppm (I instar larvae) to 21.17 ppm (pupae). Overall, this research highlighted the concrete potential of green-synthesized AgNP in the fight against dengue and its primary vector A. aegypti. Further research on structure-activity relationships of AgNP against other dengue serotypes is urgently required. PMID:26063530

  6. 75 FR 6211 - Prospective Grant of Exclusive License: Purified Inactivated Dengue Tetravalent Vaccine...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-08

    ... Viruses and Chimeric Dengue Viruses''-- European Patent Application Number 02739358.6, filed May 22, 2002... Deletion in the 3'-UTR of Dengue Types 1,2,3, and 4, or Antigenic Chimeric Dengue Viruses 1,2,3, and 4... which enhance the replication of dengue virus type 4 and an antigenic chimeric dengue virus type...

  7. 78 FR 43219 - Prospective Grant of Exclusive License: Live Attenuated Dengue Tetravalent Vaccine Containing a...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-19

    ... et al., ``Development of Mutations Useful for Attenuating Dengue Viruses and Chimeric Dengue Viruses... Antigenic Chimeric Dengue Viruses 1,2,3, And 4'', United States Patent Application Number 10/970,640 (now...., ``Mutations which enhance the replication of dengue virus type 4 and an antigenic chimeric dengue virus...

  8. Metalloprotease production by Paenibacillus larvae during the infection of honeybee larvae.

    PubMed

    Antúnez, Karina; Arredondo, Daniela; Anido, Matilde; Zunino, Pablo

    2011-05-01

    American foulbrood is a bacterial disease of worldwide distribution that affects larvae of the honeybee Apis mellifera. The causative agent is the Gram-positive, spore-forming bacterium Paenibacillus larvae. Several authors have proposed that P. larvae secretes metalloproteases that are involved in the larval degradation that occurs after infection. The aim of the present work was to evaluate the production of a metalloprotease by P. larvae during larval infection. First, the complete gene encoding a metalloprotease was identified in the P. larvae genome and its distribution was evaluated by PCR in a collection of P. larvae isolates from different geographical regions. Then, the complete gene was amplified, cloned and overexpressed, and the recombinant metalloprotease was purified and used to generate anti-metalloprotease antibodies. Metalloprotease production was evaluated by immunofluorescence and fluorescence in situ hybridization. The gene encoding a P. larvae metalloprotease was widely distributed in isolates from different geographical origins in Uruguay and Argentina. Metalloprotease was detected inside P. larvae vegetative cells, on the surface of P. larvae spores and secreted to the external growth medium. Its production was also confirmed in vivo, during the infection of honeybee larvae. This protein was able to hydrolyse milk proteins as described for P. larvae, suggesting that could be involved in larval degradation. This work contributes to the knowledge of the pathogenicity mechanisms of a bacterium of great economic significance and is one step in the characterization of potential P. larvae virulence factors. PMID:21330433

  9. Clinically Profiling Pediatric Patients with Dengue

    PubMed Central

    Pothapregada, Sriram; Kamalakannan, Banupriya; Thulasingham, Mahalaskhmy; Sampath, Srinivasan

    2016-01-01

    Objective: To study the clinical profile and outcome of dengue fever in children at a tertiary care hospital in Puducherry. Materials and Methods: All children (0-12 years of age) diagnosed and confirmed as dengue fever from August 2012 to January 2015 were reviewed retrospectively from hospital case records as per the revised World Health Organization guidelines for dengue fever. The diagnosis was confirmed by NS1 antigen-based ELISA test or dengue serology for IgM and IgG antibodies, and the data were analyzed using SPSS 16.0 statistical software. After collecting the data, all the variables were summarized by descriptive statistics. Results: Among the 261 confirmed cases of dengue fever non-severe and severe dengue infection was seen in 60.9% and 39.1%, respectively. The mean age (standard deviation) of the presentation was 6.9 + 3.3 years and male: female ratio was 1.2:1. The most common clinical manifestations were fever (94.6%), conjunctival congestion (89.6%), myalgia (81.9%), coryza (79.7%), headache (75.1%), palmar erythema (62.8%), and retro-orbital pain (51.3%). The common early warning signs at the time of admission were persistent vomiting (75.1%), liver enlargement (59.8%), cold and clammy extremities (45.2%), pain abdomen (31.0%), hypotension (29.5%), restlessness (26.4%), giddiness (23.0%), bleeding (19.9%), and oliguria (18.4%). The common manifestation of severe dengue infection was shock (39.1%), bleeding (19.9%), and multi-organ dysfunction (2.3%). The most common complications were liver dysfunction, acute respiratory distress syndrome, encephalopathy, pleural effusion, ascites, myocarditis, myositis, acute kidney injury, and disseminated intravascular coagulopathy. Platelet count did not always correlate well with the severity of bleeding. There were six deaths (2.3%) and out of them four presented with impaired consciousness (66.6%). The common causes for poor outcome were multiorgan failure, encephalopathy, and fluid refractory shock

  10. Understanding the relative importance of global dengue risk factors.

    PubMed

    Lowe, Rachel

    2015-10-01

    Dengue is a mosquito-transmitted viral infection of major international public health concern. Global environmental and socio-economic change has created ideal conditions for the global expansion of dengue transmission. Innovative modelling tools help in understanding the global determinants of dengue risk and the relative impact of environmental and socio-economic factors on dengue transmission and spread. While climatic factors may act as a limiting factor on the global scale, other processes may play a dominant role at the local level. Understanding the spatial scales at which environmental and socio-economic factors dominate can help to target appropriate dengue control and prevention strategies. PMID:26311416

  11. Anticipated and unanticipated complications of severe dengue in a primigravida

    PubMed Central

    Hashmi, Madiha; Zainab, Ghulam; Khan, Farah

    2015-01-01

    As the incidence of dengue is rising among adults more cases of dengue fever are being reported during pregnancy. Physiological changes of pregnancy mask the pathognomonic features of severe dengue such as increased hematocrit, thrombocytopenia, and leukopenia and a high index of suspicion are required in endemic areas. Massive hemorrhage may complicate operative deliveries in unsuspected patients. World Health Organization recommends that all patients with severe dengue should be admitted to a hospital with access to intensive care facilities and blood transfusion. We present the successful management of hemorrhage and unanticipated complications of severe dengue in a young primigravida admitted to the Intensive Care Unit after an emergency cesarean section. PMID:26730121

  12. Dengue vaccines: Are they safe for travelers?

    PubMed

    Halstead, Scott B; Aguiar, Maira

    2016-01-01

    The four dengue viruses (DENV) circulate among nearly one-half of the world's population in tropical and semitropical countries imposing a huge morbidity burden on travelers. Sanofipasteur has developed a tetravalent live-attenuated vaccine, Dengvaxia, recently approved by the World Health Organization and licensed in four dengue-endemic countries. An additional two dengue vaccines, developed by the National Institute of Allergy and Infectious Diseases (NIAID), USA and Takeda, are entering phase III testing. Dengvaxia is composed of four yellow fever 17D-DENV chimeras, the NIAID vaccine contains three mutagenized DENV and one DENV2/4 chimera while the Takeda vaccine contains an attenuated DENV 2 and three DENV 2-DENV chimeras. Which of these vaccines might be useful in protecting travelers against dengue infections and disease? Dengvaxia requires three doses administered over the course of one year but in addition has safety signals suggesting that susceptible individuals should not be vaccinated. The NIAID vaccine is promising as a travel vaccine as a single dose fully protected susceptible adults against live dengue 2 virus challenge. The protective efficacy and safety of the Takeda vaccine remain to be demonstrated. PMID:27343438

  13. Dengue: profile of hematological and biochemical dynamics

    PubMed Central

    Azin, Francisca Raimunda F. Guerreiro; Gonçalves, Romelia Pinheiro; Pitombeira, Maria Helena da Silva; Lima, Danielle Malta; Branco, Ivo Castelo

    2012-01-01

    Aim The objective of this study was to correlate laboratory tests during the evolution of dengue fever, comparing frequencies between the different clinical forms in order to use test results to predict the severity of the disease. Methods This is an observational, descriptive and retrospective study of 154 patients with clinical and serological diagnoses of dengue fever who, in the period from January to May 2008, were admitted in a tertiary state hospital in the city of Fortaleza that is a referral center for infectious diseases. The patients were allocated to two groups according to age: under 15 years old (n = 66) and 15 years or older (n = 88). The tests analyzed were blood count, platelet count, and serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations. Results Thrombocytopenia and elevated transaminases were observed in patients with classic dengue fever. The main laboratory abnormalities found in dengue hemorrhagic fever were thrombocytopenia, hemoconcentration and elevated transaminases, similar to severe dengue with the exception of hemoconcentration. Most laboratory abnormalities started on the 3rd day but were more evident on the 5th day with restoration of values by the 11th day; this was more prominent in under 15-year-olds and with the more severe clinical forms. Conclusion These results are relevant in assessing the disease because they can be used as markers for more severe forms and can help by enabling the adaptation of the therapeutic conduct to the needs of individual patients. PMID:23049382

  14. Current perspectives on dengue episode in Malaysia.

    PubMed

    Pang, Ee Leen; Loh, Hwei-San

    2016-04-01

    Prevalence of dengue transmission has been alarmed by an estimate of 390 million infections per annum. Urban encroachment, ecological disruption and poor sanitation are all contributory factors of increased epidemiology. Complication however arises from the fact that dengue virus inherently exists as four different serotypes. Secondary infection is often manifested in the more severe form, such that antibody-dependent enhancement (ADE) could aggravate ailment by allowing pre-existing antibodies to form complexes with infecting viruses as means of intrusion. Consequently, increased viraemic titter and suppression of antiviral response are observed. Deep concerns are thus expressed in regards to escalating trend of hospitalisation and mortality rates. In Malaysia, situation is exacerbated by improper clinical management and pending vector control operations. As a preparedness strategy against the potential deadly dengue pandemic, the call for development of a durable and cost-effective dengue vaccine against all infecting serotypes is intensified. Even though several vaccine candidates are currently being evaluated in clinical trials, uncertainties in regards to serotypes interference, incomplete protection and dose adequacy have been raised. Instead of sole reliance on outsourcing, production of local vaccine should be considered in coherent to government's efforts to combat against dengue. PMID:27086160

  15. Dengue Vectors and their Spatial Distribution

    PubMed Central

    Higa, Yukiko

    2011-01-01

    The distribution of dengue vectors, Ae. aegypti and Ae. albopictus, is affected by climatic factors. In addition, since their life cycles are well adapted to the human environment, environmental changes resulting from human activity such as urbanization exert a great impact on vector distribution. The different responses of Ae. aegypti and Ae albopictus to various environments result in a difference in spatial distribution along north-south and urban-rural gradients, and between the indoors and outdoors. In the north-south gradient, climate associated with survival is an important factor in spatial distribution. In the urban-rural gradient, different distribution reflects a difference in adult niches and is modified by geographic and human factors. The direct response of the two species to the environment around houses is related to different spatial distribution indoors and outdoors. Dengue viruses circulate mainly between human and vector mosquitoes, and the vector presence is a limiting factor of transmission. Therefore, spatial distribution of dengue vectors is a significant concern in the epidemiology of the disease. Current technologies such as GIS, satellite imagery and statistical models allow researchers to predict the spatial distribution of vectors in the changing environment. Although it is difficult to confirm the actual effect of environmental and climate changes on vector abundance and vector-borne diseases, environmental changes caused by humans and human behavioral changes due to climate change can be expected to exert an impact on dengue vectors. Longitudinal monitoring of dengue vectors and viruses is therefore necessary. PMID:22500133

  16. Autoimmune pathogenesis in dengue virus infection.

    PubMed

    Lin, Chiou-Feng; Wan, Shu-Wen; Cheng, Hsien-Jen; Lei, Huan-Yao; Lin, Yee-Shin

    2006-01-01

    The pathogenic mechanisms of dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS) caused by dengue virus (DV) infection remain unresolved. Patients with DHF/DSS are characterized by several manifestations, including severe thrombocytopenia, vascular leakage, and hepatomegaly. In addition to the effect of virus load and virus variation, abnormal immune responses of the host after DV infection may also account for the progression of DHF/DSS. Actually, viral autoimmunity is involved in the pathogenesis of numerous viral infections, such as human immunodeficiency virus, human hepatitis C virus, human cytomegalovirus, herpes simplex virus, Epstein- Barr virus, and DV. In this review, we discuss the implications of autoimmunity in dengue pathogenesis. Antibodies directed against DV nonstructural protein 1 (NS1) showed cross-reactivity with human platelets and endothelial cells, which lead to platelet and endothelial cell damage and inflammatory activation. Based on these findings, we hypothesize that anti-DV NS1 is involved in the pathogenesis of DF and DHF/DSS, and this may provide important information in dengue vaccine development. PMID:16817755

  17. Ganzfeld ERG in zebrafish larvae.

    PubMed

    Seeliger, Mathias W; Rilk, Albrecht; Neuhauss, Stephan C F

    2002-01-01

    In developmental biology, zebrafish are widely used to study the impact of mutations. The fast pace of development allows for a definitive morphological evaluation of the phenotype usually 5 days post fertilization (dpf). At that age, a functional analysis is already feasible using electroretinographic (ERG) methods. Corneal Ganzfeld ERGs were recorded with a glass microelectrode in anaesthetized, dark-adapted larvae aged 5 dpf, using a platinum wire beneath a moist paper towel as reference. ERG protocols included flash, flicker, and ON/OFF stimuli, both under scotopic and photopic conditions. Repetitive, isoluminant stimuli were used to assess the dynamic effect of pharmacological agents on the ERG. Single flash, flicker, and ON/OFF responses had adequately matured at this point to be informative. Typical signs of the cone dominance were the small scotopic a-wave and the large OFF responses. The analysis of consecutive single traces was possible because of the lack of EKG, breathing, and blink artefacts. After application of APB, which selectively blocks the ON channel via the mGluR6 receptor, the successive loss of the b-wave could be observed, which was quite different from the deterioration of the ERG after a circulatory arrest. The above techniques allowed to reliably obtain Ganzfeld ERGs in larvae aged 5 dpf. This underlines the important role of the zebrafish as a model for the functional analysis of mutations disrupting the visual system. PMID:11949809

  18. Best Practices in Dengue Surveillance: A Report from the Asia-Pacific and Americas Dengue Prevention Boards

    PubMed Central

    Beatty, Mark E.; Stone, Amy; Fitzsimons, David W.; Hanna, Jeffrey N.; Lam, Sai Kit; Vong, Sirenda; Guzman, Maria G.; Mendez-Galvan, Jorge F.; Halstead, Scott B.; Letson, G. William; Kuritsky, Joel; Mahoney, Richard; Margolis, Harold S.

    2010-01-01

    Background Dengue fever is a virus infection that is spread by the Aedes aegypti mosquito and can cause severe disease especially in children. Dengue fever is a major problem in tropical and sub-tropical regions of the world. Methodology/Principal Findings We invited dengue experts from around the world to attend meetings to discuss dengue surveillance. We reviewed literature, heard detailed reports on surveillance programs, and shared expert opinions. Results Presentations by 22 countries were heard during the 2.5 day meetings. We describe the best methods of surveillance in general, the stakeholders in dengue surveillance, and the steps from mosquito bite to reporting of a dengue case to explore how best to carry out dengue surveillance. We also provide details and a comparison of the dengue surveillance programs by the presenting countries. Conclusions/Significance The experts provided recommendations for achieving the best possible data from dengue surveillance accepting the realities of the real world (e.g., limited funding and staff). Their recommendations included: (1) Every dengue endemic country should make reporting of dengue cases to the government mandatory; (2) electronic reporting systems should be developed and used; (3) at minimum dengue surveillance data should include incidence, hospitalization rates, deaths by age group; (4) additional studies should be completed to check the sensitivity of the system; (5) laboratories should share expertise and data; (6) tests that identify dengue virus should be used in patients with fever for four days or less and antibody tests should be used after day 4 to diagnose dengue; and (7) early detection and prediction of dengue outbreaks should be goals for national surveillance systems. PMID:21103381

  19. Current perspectives on the spread of dengue in India

    PubMed Central

    Gupta, Ekta; Ballani, Neha

    2014-01-01

    Dengue fever (DF) and dengue hemorrhagic fever (DHF) are important arthropod-borne viral diseases. Each year, there are ~50 million dengue infections and ~500,000 individuals are hospitalized with DHF, mainly in Southeast Asia. Dengue in India has dramatically expanded over the last few decades, with rapidly changing epidemiology. The first major DHF outbreak in the entire nation occurred in 1996 by dengue virus serotype 2, and after a gap of almost a decade, the country faced yet another DF outbreak in the year 2003 by dengue virus serotype 3. A dramatic increase in the number and frequency of outbreaks followed, and, at present, in most of the states of India, dengue is almost endemic. At present, all the four serotypes are seen in circulation, but the predominant serotype keeps changing. Despite this trend, surveillance, reporting, and diagnosis of dengue remain largely passive in India. More active community-based epidemiological studies with intensive vector control and initiatives for dengue vaccine development should be geared up to control the spread of dengue in India. We review here the factors that may have contributed to the changing epidemiology of dengue in India. PMID:25525374

  20. Current perspectives on the spread of dengue in India.

    PubMed

    Gupta, Ekta; Ballani, Neha

    2014-01-01

    Dengue fever (DF) and dengue hemorrhagic fever (DHF) are important arthropod-borne viral diseases. Each year, there are ~50 million dengue infections and ~500,000 individuals are hospitalized with DHF, mainly in Southeast Asia. Dengue in India has dramatically expanded over the last few decades, with rapidly changing epidemiology. The first major DHF outbreak in the entire nation occurred in 1996 by dengue virus serotype 2, and after a gap of almost a decade, the country faced yet another DF outbreak in the year 2003 by dengue virus serotype 3. A dramatic increase in the number and frequency of outbreaks followed, and, at present, in most of the states of India, dengue is almost endemic. At present, all the four serotypes are seen in circulation, but the predominant serotype keeps changing. Despite this trend, surveillance, reporting, and diagnosis of dengue remain largely passive in India. More active community-based epidemiological studies with intensive vector control and initiatives for dengue vaccine development should be geared up to control the spread of dengue in India. We review here the factors that may have contributed to the changing epidemiology of dengue in India. PMID:25525374

  1. Dengue: the risk to developed and developing countries.

    PubMed Central

    Monath, T P

    1994-01-01

    Dengue viruses are members of the Flaviviridae, transmitted principally in a cycle involving humans and mosquito vectors. In the last 20 years the incidence of dengue fever epidemics has increased and hyperendemic transmission has been established over a geographically expanding area. A severe form, dengue hemorrhagic fever (DHF), is an immunopathologic disease occurring in persons who experience sequential dengue infections. The risk of sequential infections, and consequently the incidence of DHF, has risen dramatically, first in Asia and now in the Americas. At the root of the emergence of dengue as a major health problem are changes in human demography and behavior, leading to unchecked populations of and increased exposure to the principal domestic mosquito vector, Aedes aegypti. Virus-specified factors also influence the epidemiology of dengue. Speculations on future events in the epidemiology, evolution, and biological expression of dengue are presented. Images PMID:8146129

  2. Diagnosis of Dengue Infection Using Conventional and Biosensor Based Techniques.

    PubMed

    Parkash, Om; Shueb, Rafidah Hanim

    2015-10-01

    Dengue is an arthropod-borne viral disease caused by four antigenically different serotypes of dengue virus. This disease is considered as a major public health concern around the world. Currently, there is no licensed vaccine or antiviral drug available for the prevention and treatment of dengue disease. Moreover, clinical features of dengue are indistinguishable from other infectious diseases such as malaria, chikungunya, rickettsia and leptospira. Therefore, prompt and accurate laboratory diagnostic test is urgently required for disease confirmation and patient triage. The traditional diagnostic techniques for the dengue virus are viral detection in cell culture, serological testing, and RNA amplification using reverse transcriptase PCR. This paper discusses the conventional laboratory methods used for the diagnosis of dengue during the acute and convalescent phase and highlights the advantages and limitations of these routine laboratory tests. Subsequently, the biosensor based assays developed using various transducers for the detection of dengue are also reviewed. PMID:26492265

  3. Clinical and Oral Implications of Dengue Fever: A Review

    PubMed Central

    Roopashri, G; Vaishali, M R; David, Maria Priscilla; Baig, Muqeet; Navneetham, Anuradha; Venkataraghavan, Karthik

    2015-01-01

    Dengue is a viral infection with fatal potential complications. It is also called as break-bone fever. Worldwide dengue infection is the most common mosquito-borne viral disease. It is caused by vector Aedesa egypti and represents a major public health issue in more than 100 tropical countries. The word dengue is obtained from Swahili phrase Ka-dinga pepo meaning “cramplikeseizure.” Dengue viral infections are characterized by abrupt febrile illness, but can also lead to significant morbidity and mortality. Hence, it requires an early and correct diagnosis. Gingival bleeding is the most common oral manifestation of dengue infection. Although oral lesions are uncommon in dengue infections and if manifested, may be mistaken for bleeding disorders. This review emphasizes the significance of oral lesions as it may be the early indicators of dengue hemorrhagic fever. PMID:25859113

  4. Dengue vaccine: a valuable asset for the future.

    PubMed

    Jindal, Harashish; Bhatt, Bhumika; Malik, Jagbir Singh; S K, Shashikantha

    2014-01-01

    Dengue has emerged as one of the major global public health problems. The disease has broken out of its shell and has spread due to increased international travel and climatic changes. Globally, over 2.5 billion people accounting for >40% of the world's population are at risk from dengue. Since the 1940s, dengue vaccines have been under investigation. A live-attenuated tetravalent vaccine based on chimeric yellow fever-dengue virus (CYD-TDV) has progressed to phase III efficacy studies. Dengue vaccine has been found to be a cost-effective intervention to reduce morbidity and mortality. Current dengue vaccine candidates aim to protect against the 4 dengue serotypes, but the recent discovery of a fifth serotype could complicate vaccine development. In recent years, an urgent need has been felt for a vaccine to prevent the morbidity and mortality from this disease in a cost-effective way. PMID:25424928

  5. Diagnosis of Dengue Infection Using Conventional and Biosensor Based Techniques

    PubMed Central

    Parkash, Om; Hanim Shueb, Rafidah

    2015-01-01

    Dengue is an arthropod-borne viral disease caused by four antigenically different serotypes of dengue virus. This disease is considered as a major public health concern around the world. Currently, there is no licensed vaccine or antiviral drug available for the prevention and treatment of dengue disease. Moreover, clinical features of dengue are indistinguishable from other infectious diseases such as malaria, chikungunya, rickettsia and leptospira. Therefore, prompt and accurate laboratory diagnostic test is urgently required for disease confirmation and patient triage. The traditional diagnostic techniques for the dengue virus are viral detection in cell culture, serological testing, and RNA amplification using reverse transcriptase PCR. This paper discusses the conventional laboratory methods used for the diagnosis of dengue during the acute and convalescent phase and highlights the advantages and limitations of these routine laboratory tests. Subsequently, the biosensor based assays developed using various transducers for the detection of dengue are also reviewed. PMID:26492265

  6. Physiological and Morphological Aspects of Aedes aegypti Developing Larvae: Effects of the Chitin Synthesis Inhibitor Novaluron

    PubMed Central

    Farnesi, Luana C.; Brito, José M.; Linss, Jutta G.; Pelajo-Machado, Marcelo; Valle, Denise; Rezende, Gustavo L.

    2012-01-01

    Population control of the dengue vector mosquito, Aedes aegypti, is difficult due to many reasons, one being the development of resistance to neurotoxic insecticides employed. The biosynthesis of chitin, a major constituent of insect cuticle, is a novel target for population control. Novaluron is a benzoylphenylurea (BPU) that acts as a chitin synthesis inhibitor, already used against mosquitoes. However, information regarding BPU effects on immature mosquito stages and physiological parameters related with mosquito larval development are scarce. A set of physiological parameters were recorded in control developing larvae and novaluron was administered continuously to Ae. aegypti larvae, since early third instar. Larval instar period duration was recorded from third instar until pupation. Chitin content was measured during third and fourth instars. Fourth instars were processed histochemically at the mesothorax region, stained with hematoxylin and eosin (HE) for assessment of internal tissues, and labeled with WGA-FITC to reveal chitinized structures. In control larvae: i) there is a chitin content increase during both third and fourth instars where late third instars contain more chitin than early fourth instars; ii) thoracic organs and a continuous cuticle, closely associated with the underlying epidermis were observed; iii) chitin was continuously present throughout integument cuticle. Novaluron treatment inhibited adult emergence, induced immature mortality, altered adult sex ratio and caused delay in larval development. Moreover, novaluron: i) significantly affected chitin content during larval development; ii) induced a discontinuous and altered cuticle in some regions while epidermis was often thinner or missing; iii) rendered chitin cuticle presence discontinuous and less evident. In both control and novaluron larvae, chitin was present in the peritrophic matrix. This study showed quantitatively and qualitatively evidences of novaluron effects on Ae

  7. Dengue haemorrhagic fever with unusual prolonged thrombocytopaenia.

    PubMed

    Kamil, S M; Mohamad, N H; Narazah, M Y; Khan, F A

    2006-04-01

    We describe a case of dengue haemorrhagic fever with prolonged thrombocytopaenia. A 22-year-old Malay man with no prior illness presented with a history of fever and generalised macular rash of four days duration. Initial work-up suggested the diagnosis of dengue haemorrhagic fever based on thrombocytopaenia and positive dengue serology. Patient recovered from acute illness by day ten, and was discharged from the hospital with improving platelet count. He was then noted to have declining platelet count on follow-up and required another hospital admission on day 19 of his illness because of declining platelet count. The patient remained hospitalised till day 44 of his illness and managed with repeated platelet transfusion and supportive care till he recovered spontaneously. PMID:16572249

  8. Optimal Repellent Usage to Combat Dengue Fever.

    PubMed

    Dorsett, Chasity; Oh, Hyunju; Paulemond, Marie Laura; Rychtář, Jan

    2016-05-01

    Dengue fever is one of the most important vector-borne diseases. It is transmitted by Aedes Stegomyia aegypti, and one of the most effective strategies to combat the disease is the reduction of exposure to bites of these mosquitoes. In this paper, we present a game-theoretical model in which individuals choose their own level of protection against mosquito bites in order to maximize their own benefits, effectively balancing the cost of protection and the risk of contracting the dengue fever. We find that even when the usage of protection is strictly voluntary, as soon as the cost of protection is about 10,000 times less than the cost of contracting dengue fever, the optimal level of protection will be within 5 % of the level needed for herd immunity. PMID:27142427

  9. Suppression of Drug Resistance in Dengue Virus

    PubMed Central

    Mateo, Roberto; Nagamine, Claude M.

    2015-01-01

    ABSTRACT Dengue virus is a major human pathogen responsible for 400 million infections yearly. As with other RNA viruses, daunting challenges to antiviral design exist due to the high error rates of RNA-dependent RNA synthesis. Indeed, treatment of dengue virus infection with a nucleoside analog resulted in the expected genetic selection of resistant viruses in tissue culture and in mice. However, when the function of the oligomeric core protein was inhibited, no detectable selection of drug resistance in tissue culture or in mice was detected, despite the presence of drug-resistant variants in the population. Suppressed selection of drug-resistant virus correlated with cooligomerization of the targeted drug-susceptible and drug-resistant core proteins. The concept of “dominant drug targets,” in which inhibition of oligomeric viral assemblages leads to the formation of drug-susceptible chimeras, can therefore be used to prevent the outgrowth of drug resistance during dengue virus infection. PMID:26670386

  10. Dengue virus growth, purification, and fluorescent labeling.

    PubMed

    Zhang, Summer; Chan, Kuan Rong; Tan, Hwee Cheng; Ooi, Eng Eong

    2014-01-01

    The early events of the dengue virus life cycle involve virus binding, internalization, trafficking, and fusion. Fluorescently labeled viruses can be used to visualize these early processes. As dengue virus has 180 identical copies of the envelope protein attached to the membrane surface and is surrounded by a lipid membrane, amine-reactive (Alexa Fluor) or lipophilic (DiD) dyes can be used for virus labeling. These dyes are highly photostable and are ideal for studies involving cellular uptake and endosomal transport. To improve virus labeling efficiency and minimize the nonspecific labeling of nonviral proteins, virus concentration and purification precede fluorescent labeling of dengue viruses. Besides using these viruses for single-particle tracking, DiD-labeled viruses can also be used to distinguish serotype-specific from cross-neutralizing antibodies. Here the details of virus concentration, purification, virus labeling, applications, and hints of troubleshooting are described. PMID:24696327

  11. Dengue vaccines: challenges, development, current status and prospects.

    PubMed

    Ghosh, A; Dar, L

    2015-01-01

    Infection with dengue virus (DENV) is the most rapidly spreading mosquito-borne viral disease in the world. The clinical spectrum of dengue, caused by any of the four serotypes of DENV, ranges from mild self-limiting dengue fever to severe dengue, in the form dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Increased rates of hospitalization due to severe dengue, during outbreaks, result in massive economic losses and strained health services. In the absence of specific antiviral therapy, control of transmission of DENV by vector management is the sole method available for decreasing dengue-associated morbidity. Since vector control strategies alone have not been able to satisfactorily achieve reduction in viral transmission, the implementation of a safe, efficacious and cost-effective dengue vaccine as a supplementary measure is a high public health priority. However, the unique and complex immunopathology of dengue has complicated vaccine development. Dengue vaccines have also been challenged by critical issues like lack of animal models for the disease and absence of suitable markers of protective immunity. Although no licensed dengue vaccine is yet available, several vaccine candidates are under phases of development, including live attenuated virus vaccines, live chimeric virus vaccines, inactivated virus vaccines, subunit vaccines, DNA vaccines and viral-vectored vaccines. Although some vaccine candidates have progressed from animal trials to phase II and III in humans, a number of issues regarding implementation of dengue vaccine in countries like India still need to be addressed. Despite the current limitations, collaborative effects of regulatory bodies like World Health Organization with vaccine manufacturers and policy makers, to facilitate vaccine development and standardize field trials can make a safe and efficacious dengue vaccine a reality in near future. PMID:25559995

  12. Workbook on Identification of Aedes Aegypti Larvae.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; And Others

    This self-instructional booklet is designed to enable yellow fever control workers to identify the larvae of "Aedes aegypti." The morphological features of mosquito larvae are illustrated in this partially programed text, and the distinguishing features of "A. aegypti" indicated. A glossary is included. (AL)

  13. An epidemiological study of dengue in Delhi, India.

    PubMed

    Vikram, Kumar; Nagpal, B N; Pande, Veena; Srivastava, Aruna; Saxena, Rekha; Anvikar, Anup; Das, Aparup; Singh, Himmat; Anushrita; Gupta, Sanjeev K; Tuli, N R; Telle, Olivier; Yadav, N K; Valecha, Neena; Paul, Richard

    2016-01-01

    Delhi, the capital of India, is an important metropolitan hub for major financial and sociocultural exchanges, offering challenging threats to current public health infrastructure. In recent past, an upsurge of dengue cases in Delhi posed a significant menace to the existing dengue control policies. To reform the control strategies and take timely intervention to prevent future epidemics, an epidemiological study on the proportion of both asymptomatic and symptomatic dengue infections in selected population was conducted. The aim of the study was to investigate and assess the epidemiology of dengue infection and to estimate the proportion of asymptomatic and symptomatic dengue infections in Delhi. In this study, around 50 confirmed dengue cases, a total of 2125 individuals as household and neighbourhood contacts, with or without dengue febrile illness, were finger pricked and serologically detected as dengue positive or negative using SD Duo Bioline Rapid Diagnostic Test (SD Inc, Korea) with NS1, IgM & IgG combo test, which detected dengue virus antigen and antibodies to dengue virus in human blood. Out of 2125 individuals, 768 (36.1%) individuals showed positive dengue test with past (25.5%), primary (1.88%) or secondary (8.8%) dengue infections. Higher percentage of IgG was found in age groups 15-24 years and 25-50 years (36% each). Infants (<1 year) presented higher incidence of new infections (22% of NS1+IgM positives) as compared to adults. Further analysis revealed that out of the 226 newly infected cases (including NS1 and IgM positives), 142 (63%) were asymptomatic and 84 (37%) were symptomatic, as per WHO guidelines. Our findings also suggest that out of the total population screened, 10.6% dengue infection was either primary or secondary. On the basis of these results, it may be hypothesized that there are large number of asymptomatic dengue infections in the community as compared to reported symptomatic cases in Delhi. For the effective control of dengue

  14. Cost of dengue outbreaks: literature review and country case studies

    PubMed Central

    2013-01-01

    Background Dengue disease surveillance and vector surveillance are presumed to detect dengue outbreaks at an early stage and to save – through early response activities – resources, and reduce the social and economic impact of outbreaks on individuals, health systems and economies. The aim of this study is to unveil evidence on the cost of dengue outbreaks. Methods Economic evidence on dengue outbreaks was gathered by conducting a literature review and collecting information on the costs of recent dengue outbreaks in 4 countries: Peru, Dominican Republic, Vietnam, and Indonesia. The literature review distinguished between costs of dengue illness including cost of dengue outbreaks, cost of interventions and cost-effectiveness of interventions. Results Seventeen publications on cost of dengue showed a large range of costs from 0.2 Million US$ in Venezuela to 135.2 Million US$ in Brazil. However, these figures were not standardized to make them comparable. Furthermore, dengue outbreak costs are calculated differently across the publications, and cost of dengue illness is used interchangeably with cost of dengue outbreaks. Only one paper from Australia analysed the resources saved through active dengue surveillance. Costs of vector control interventions have been reported in 4 studies, indicating that the costs of such interventions are lower than those of actual outbreaks. Nine papers focussed on the cost-effectiveness of dengue vaccines or dengue vector control; they do not provide any direct information on cost of dengue outbreaks, but their modelling methodologies could guide future research on cost-effectiveness of national surveillance systems. The country case studies – conducted in very different geographic and health system settings - unveiled rough estimates for 2011 outbreak costs of: 12 million US$ in Vietnam, 6.75 million US$ in Indonesia, 4.5 million US$ in Peru and 2.8 million US$ in Dominican Republic (all in 2012 US$). The proportions of the

  15. [Increase of entomological indices during the pre-epidemic period of dengue in Ben Tre, South Vietnam].

    PubMed

    Nguyen, T P Q; Luu, L L; Vu, T Q H; Buisson, Y

    2011-10-01

    Dengue has emerged in Vietnam 50 years ago and since has become endemo-epidemic throughout the whole country. Each year, major epidemics of dengue fever (DF) and dengue hemorrhagic fever (DHF) hit South Vietnam during the rainy season, causing significant morbidity and mortality, especially among young children. The only preventive measure is vector control, but it is often implemented too late or indiscriminately. The aim of this study was to investigate, in the pre-epidemic stage, the existence of significant changes in vector indices, which will predict DF/DHF outbreaks. We conducted a descriptive transversal study, repeated once a month for four months (March to June) in the village of Locthuan (province Ben Tre) in the Mekong's delta. Adult mosquitoes were caught in 30 houses, and larvae were collected in water holding containers of 50 houses. The houses were randomly selected. Vector densities were calculated according to the indices recommended by WHO. Virological analysis was carried out on lots of female Aedes and larvae in order to determine viral infection rates. Catches of adult mosquitoes collected 496 specimens including 329 Aedes, 139 Culex and 28 Anopheles. Aedes aegypti was present in 63% of visited homes that is an average density of 1.8 mosquitoes per house. The increase in imaginal indices during the 4 months was not significant. The survey of breeding sites of Ae. aegypti identified 1292 water containers in which 71,569 larval specimens were collected. The values of house index, container index [CI] and Breteau index [BI] increased each month, the latter from 166 to 442. This increase was significant for CI and BI. Breeding sites were mostly intra-home, mainly consisting of large and small ceramic jars. Larval density of Ae. aegypti in the containers also increased significantly over the 4 months. It was correlated with the lack of cover and predators such as Mesocyclops spp., Micronecta spp. and larvivorous fishes. Cultivation of 15 pools of

  16. Understanding dengue pathogenesis: implications for vaccine design.

    PubMed Central

    Stephenson, John R.

    2005-01-01

    In the second half of the twentieth century dengue spread throughout the tropics, threatening the health of a third of the world's population. Dengue viruses cause 50-100 million cases of acute febrile disease every year, including more than 500,000 reported cases of the severe forms of the disease--dengue haemorrhagic fever and dengue shock syndrome. Attempts to create conventional vaccines have been hampered by the lack of suitable experimental models, the need to provide protection against all four serotypes simultaneously and the possible involvement of virus-specific immune responses in severe disease. The current understanding of dengue pathogenesis is outlined in this review, with special emphasis on the role of the immune response. The suspected involvement of the immune system in increased disease severity and vascular damage has raised concerns about every vaccine design strategy proposed so far. Clearly more research is needed on understanding the correlates of protection and mechanisms of pathogenesis. There is, however, an urgent need to provide a solution to the escalating global public health problems caused by dengue infections. Better disease management, vector control and improved public health measures will help reduce the current disease burden, but a safe and effective vaccine is probably the only long-term solution. Although concerns have been raised about the possible safety and efficacy of both conventional and novel vaccine technologies, the situation is now so acute that it is not possible to wait for the perfect vaccine. Consequently the careful and thorough evaluation of several of the current candidate vaccines may be the best approach to halting the spread of disease. PMID:15868023

  17. Dengue in China: a clinical review.

    PubMed Central

    Qiu, F. X.; Gubler, D. J.; Liu, J. C.; Chen, Q. Q.

    1993-01-01

    Three etiologically proven outbreaks of dengue fever and one etiologically confirmed epidemic of dengue haemorrhagic fever have occurred in south China since 1978. The first of these, an epidemic of dengue due to virus type 4 took place in Shiwan town, Foshan city, Guangdong Province, in 1978; the epidemic began in May and ended in November. The clinical manifestations of 583 hospitalized patients were observed from August to October. The majority (81.3%) of patients were aged 21-50 years (male:female = 1.2:1). The course of illness was about 1 week in most cases; three patients (0.5%) died. A local outbreak of dengue due to virus type 1 occurred in Shiqi town, Zhongshan County, Guangdong Province, from September to November 1979. The majority of patients were older children and adolescents. There was no marked difference between males and females in terms of the course of the illness, and there were no complications or deaths. A large epidemic of dengue due to virus type 3 occurred on Hainan Island in 1980. The clinical manifestations of 510 hospitalized patients (mostly adolescents and adults) were observed from April to September. Some patients developed rare complications, such as loss of hair, acute intravascular haemolysis, and multiple peripheral paralysis; there were four deaths (0.78%). The first known epidemic of dengue haemorrhagic fever in China occurred among 10-29-year-olds on Hainan Island in 1985 and 1986. There were no essential differences between males and females. Some cases had rare complications such as acute intravascular haemolysis, while others had diffuse intravascular coagulation and altered mental status; 10 patients (6.5%) died. PMID:8324854

  18. Endothelial cells in dengue hemorrhagic fever.

    PubMed

    Srikiatkhachorn, Anon; Kelley, James F

    2014-09-01

    Therapies to prevent or reverse endothelial dysfunction and vascular leak found in dengue hemorrhagic fever (DHF) have not been identified. In this review we summarize dengue viruses and the spectrum of human disease and highlight evidence of endothelial cell dysfunction in DHF based on studies in patients and mouse and tissue culture models. Evidence suggests that both virus antigen and host immune response, can cause endothelial cell dysfunction and weaken endothelial barrier integrity. We suggest possible therapeutic interventions and highlight how therapies targeting altered endothelial function might be evaluated in animal models and in patients with DHF. PMID:25025934

  19. Transstadial Effects of Bti on Traits of Aedes aegypti and Infection with Dengue Virus

    PubMed Central

    Alto, Barry W.; Lord, Cynthia C.

    2016-01-01

    Most mosquito control efforts are primarily focused on reducing the adult population size mediated by reductions in the larval population, which should lower risk of disease transmission. Although the aim of larviciding is to reduce larval abundance and thus recruitment of adults, nonlethal effects on adults are possible, including transstadial effects on phenotypes of adults such as survival and pathogen infection and transmission. In addition, the mortality induced by control efforts may act in conjunction with other sources of mosquito mortality in nature. The consequences of these effects and interactions may alter the potential of the population to transmit pathogens. We tested experimentally the combined effects of a larvicide (Bacillus thuringiensis ssp. israelensis, Bti) and competition during the larval stages on subsequent Aedes aegypti (Linnaeus) traits, population performance, and susceptibility to dengue-1 virus infection. Ae. aegypti that survived exposure to Bti experienced accelerated development, were larger, and produced more eggs with increasing amounts of Bti, consistent with competitive release among surviving mosquitoes. Changing larval density had no significant interactive effect with Bti treatment on development and growth to adulthood. Larval density, but not Bti or treatment interaction, had a strong effect on survival of adult Ae. aegypti females. There were sharper declines in cumulative daily survival of adults from crowded than uncrowded larval conditions, suggesting that high competition conditions of larvae may be an impediment to transmission of dengue viruses. Rates of infection and dengue-1 virus disseminated infections were found to be 87±13% and 88±12%, respectively. There were no significant treatment effects on infection measurements. Our findings suggest that larvicide campaigns using Bti may reduce the number of emerged adults, but survivors will have a fitness advantage (growth, development, enhanced production of eggs

  20. Transstadial Effects of Bti on Traits of Aedes aegypti and Infection with Dengue Virus.

    PubMed

    Alto, Barry W; Lord, Cynthia C

    2016-02-01

    Most mosquito control efforts are primarily focused on reducing the adult population size mediated by reductions in the larval population, which should lower risk of disease transmission. Although the aim of larviciding is to reduce larval abundance and thus recruitment of adults, nonlethal effects on adults are possible, including transstadial effects on phenotypes of adults such as survival and pathogen infection and transmission. In addition, the mortality induced by control efforts may act in conjunction with other sources of mosquito mortality in nature. The consequences of these effects and interactions may alter the potential of the population to transmit pathogens. We tested experimentally the combined effects of a larvicide (Bacillus thuringiensis ssp. israelensis, Bti) and competition during the larval stages on subsequent Aedes aegypti (Linnaeus) traits, population performance, and susceptibility to dengue-1 virus infection. Ae. aegypti that survived exposure to Bti experienced accelerated development, were larger, and produced more eggs with increasing amounts of Bti, consistent with competitive release among surviving mosquitoes. Changing larval density had no significant interactive effect with Bti treatment on development and growth to adulthood. Larval density, but not Bti or treatment interaction, had a strong effect on survival of adult Ae. aegypti females. There were sharper declines in cumulative daily survival of adults from crowded than uncrowded larval conditions, suggesting that high competition conditions of larvae may be an impediment to transmission of dengue viruses. Rates of infection and dengue-1 virus disseminated infections were found to be 87±13% and 88±12%, respectively. There were no significant treatment effects on infection measurements. Our findings suggest that larvicide campaigns using Bti may reduce the number of emerged adults, but survivors will have a fitness advantage (growth, development, enhanced production of eggs

  1. Natural vertical transmission of dengue viruses in Aedes aegypti in selected sites in Cebu City, Philippines.

    PubMed

    Edillo, Frances E; Sarcos, Janet R; Sayson, Stephanie L

    2015-12-01

    We attempted to determine the vertical transmission of dengue virus (DENV) in Aedes aegypti in selected sites in Cebu City, Philippines. Mosquito sub-adults were collected monthly from households and the field during the wet-dry-wet season from November, 2011 to July, 2012 and were laboratory-reared to adults. Viral RNA extracts in mosquitoes were assayed by hemi-nested RT-PCR. Results showed that 62 (36.26%; n=679) out of 171 mosquito pools (n=2,871) were DENV+. The minimum infection rate (MIR) of DENV ranged from 0 in wet months to 48.22/1,000 mosquitoes in April, 2012 (mid-dry). DENVs were detected in larvae, pupae, and male and female adults, with DENV-4, DENV-3, and DENV-1, in that rank of prevalence. DENV-1 co-infected with either DENV-3 or -4 or with both in April, 2012; DENV-3 and -4 were present in both seasons. More DENV+ mosquitoes were collected from households than in field premises (p<0.001) and in the dry than in the wet season (p<0.05), with significant interaction (p<0.05) between sites and premises but no interaction between sites and seasons (p>0.05). By Generalized Linear Mixed models, the type of premises nested in sites and monthly total rainfall were significant predictors of monthly dengue cases (p<0.05) and not MIR, season, temperature, and relative humidity. Surveillance of DENV prevalence in Ae. aegypti and detecting their natural foci in the dry season provide an early warning signal of dengue outbreak. PMID:26611963

  2. Symptoms and What To Do If You Think You Have Dengue

    MedlinePlus

    ... Publications and Related Links Dengue Branch Dengue in Puerto Rico Dengue Update Get Email Updates To receive email ... of Hospitals, laboratories and health care centers in Puerto Rico that will draw serum samples, in Spanish. [DOC ...

  3. Complete Genome Sequence of a Dengue Virus Serotype 4 Strain Isolated in Roraima, Brazil

    PubMed Central

    Souza, Victor C.; Silva, George A. V.; Maito, Rodrigo M.; Granja, Fabiana; Siqueira, Thalita; Acosta, Pablo O. A.

    2012-01-01

    Dengue is the most important arboviral disease worldwide. We report the complete genome sequence of a dengue virus serotype 4, genotype II strain isolated in 2010 from a patient with classical dengue fever in Boa Vista, Roraima, Brazil. PMID:22247521

  4. Characterization of the 2013 dengue epidemic in Myanmar with dengue virus 1 as the dominant serotype.

    PubMed

    Ngwe Tun, Mya Myat; Kyaw, Aung Kyaw; Makki, Nader; Muthugala, Rohitha; Nabeshima, Takeshi; Inoue, Shingo; Hayasaka, Daisuke; Moi, Meng Ling; Buerano, Corazon C; Thwe, Saw Myat; Thant, Kyaw Zin; Morita, Kouichi

    2016-09-01

    In 2013 in Myanmar, dengue epidemic occurred with 20,255 cases including 84 deaths. This study aimed to determine the serological and molecular characteristics of dengue virus (DENV) infection among children with clinical diagnosis of dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS) during this period. Single acute serum samples were collected from 300 children in Mandalay Children Hospital, Mandalay, Myanmar. Out of the 300 children, 175 (58.3%) and 183 (61%) were positive for anti-dengue IgM and anti-dengue IgG, respectively. Among the IgM positives, 41 (23.4%) had primary DENV infection. Thirty-nine DENV strains (23 DENV-1, 10 DENV-2 and 6 DENV-4) were successfully isolated after inoculation of the patient serum samples onto C6/36 cells. DENV 1 was the dominant serotype in the 2013 epidemic. There was no correlation between the infecting serotypes and clinical severities. The DENV-1 strains belonged to three lineages of the genotype 1; the DENV-2 strains were of the Asian I genotype and were separated into two lineages; and DENV-4 strains belonged to the same lineage of genotype I. It is of interest to note the diversity of DENV-1 and -2 circulating in the same location during June-August 2013. These DENV isolates were genetically close (98%-100%) to the other previously reported isolates from Myanmar and its neighboring countries, namely China, Thailand, Sri Lanka, Cambodia and Vietnam. Primary DENV infection was still high among the severe dengue cases. Different serotypes of DENV were co-circulating in 2013, however, genotype shift was not observed. Additionally, amino acid mutations were detected in the study strains not seen in the previously reported strains from other countries and Myanmar. This paper provided information on the circulating serotypes for the last 15years and the recent dengue situation in Mandalay, Myanmar after 2006. PMID:27154331

  5. Knowledge, Awareness and Practices Regarding Dengue Fever among the Adult Population of Dengue Hit Cosmopolitan

    PubMed Central

    Itrat, Ahmed; Khan, Abdullah; Javaid, Sunniya; Kamal, Mahwash; Khan, Hassan; Javed, Sannia; Kalia, Saira; Khan, Adil Haleem; Sethi, Muhammad Imran; Jehan, Imtiaz

    2008-01-01

    Background The World health Organization (WHO) declares dengue and dengue hemorrhagic fever to be endemic in South Asia. Despite the magnitude of problem, no documented evidence exists in Pakistan which reveals the awareness and practices of the country's adult population regarding dengue fever, its spread, symptoms, treatment and prevention. This study was conducted to assess the level of knowledge, attitudes and practices regarding dengue fever in people visiting tertiary care hospitals in Karachi, Pakistan. Methods A cross-sectional pilot study was conducted among people visiting tertiary care hospitals in Karachi. Through convenience sampling, a pre-tested and structured questionnaire was administered through a face-to-face unprompted interview with 447 visitors. Knowledge was recorded on a scale of 1–3. Results About 89.9% of individuals interviewed had heard of dengue fever. Sufficient knowledge about dengue was found to be in 38.5% of the sample, with 66% of these in Aga Khan University Hospital and 33% in Civil Hospital Karachi. Literate individuals were relatively more well-informed about dengue fever as compared to the illiterate people (p<0.001). Knowledge based upon preventive measures was found to be predominantly focused towards prevention of mosquito bites (78.3%) rather than eradication of mosquito population (17.3%). Use of anti- mosquito spray was the most prevalent (48.1%) preventive measure. Television was considered as the most important and useful source of information on the disease. Conclusion Adult population of Karachi has adequate knowledge related to the disease ‘dengue’ on isolated aspects, but the overall prevalence of ‘sufficient knowledge’ based on our criteria is poor. We demonstrated adequate prevalence of preventive practices against the disease. Further studies correlating the association between knowledge and its effectiveness against dengue will be helpful in demonstrating the implications of awareness campaigns. PMID

  6. Epidemiology and vector efficiency during a dengue fever outbreak in Cixi, Zhejiang Province, China.

    PubMed

    Yang, Tianci; Lu, Liang; Fu, Guiming; Zhong, Shi; Ding, Gangqiang; Xu, Rong; Zhu, Guangfeng; Shi, Nanfeng; Fan, Feilong; Liu, Qiyong

    2009-06-01

    An emigrant worker returning from Southeast Asia triggered the outbreak of a DF epidemic in Zhejiang province, China, in October, 2004. Eighty-three cases, mainly young and middle-aged people between 20 and 50 (78.3%), were reported in the area of Cixi. There were no obvious occupational patterns. The majority of cases were female, with a sex ratio of 1:1.86 (m:f). The dengue virus (DENV) strains from the epidemic area were isolated and identified as DENV-1, which belongs to Asian strain 1. According to the epidemiological investigation, the incidence of DF had no relationship to temperature, humidity, or precipitation, and the Breteau index of larvae showed a clear relationship only with the House Index and Container Index. Recent dengue problems in the town have been associated with the complex social factors and hygienic conditions for endemic villagers and immigrant workers. Some hygienic measures should be taken by the local government to reduce the risk of mosquito-borne disease. These measures should aim to eliminate the breeding sites of the vector Aedes albopictus in indoor and outdoor containers filled with rainwater and thus reducing the risk of DF transmission. PMID:20836815

  7. Indirect effects of cigarette butt waste on the dengue vector Aedes aegypti (Diptera: Culicidae).

    PubMed

    Dieng, Hamady; Rajasaygar, Sudha; Ahmad, Abu Hassan; Rawi, Che Salmah Md; Ahmad, Hamdan; Satho, Tomomitsu; Miake, Fumio; Zuharah, Wan Fatma; Fukumitsu, Yuki; Saad, Ahmad Ramli; Abdul Hamid, Suhaila; Vargas, Ronald Enrique Morales; Ab Majid, Abdul Hafiz; Fadzly, Nik; Abu Kassim, Nur Faeza; Hashim, Nur Aida; Abd Ghani, Idris; Abang, Fatimah Bt; AbuBakar, Sazaly

    2014-02-01

    Despite major insecticide-based vector control programs, dengue continues to be a major threat to public health in urban areas. The reasons for this failure include the emergence of insecticide resistance and the narrowing of the spectrum of efficient products. Cigarette butts (CBs), the most commonly discarded piece of waste, also represent a major health hazard to human and animal life. CBs are impregnated with thousands of chemical compounds, many of which are highly toxic and none of which has history of resistance in mosquitoes. This study was performed to examine whether exposure to CB alters various biological parameters of parents and their progeny. We examined whether the mosquito changes its ovipositional behaviors, egg hatching, reproductive capacity, longevity and fecundity in response to CB exposure at three different concentrations. Females tended to prefer microcosms containing CBs for egg deposition than those with water only. There were equivalent rates of eclosion success among larvae from eggs that matured in CB and water environments. We also observed decreased life span among adults that survived CB exposure. Extracts of CB waste have detrimental effects on the fecundity and longevity of its offspring, while being attractive to its gravid females. These results altogether indicate that CB waste indirectly affect key adult life traits of Aedes aegypti and could conceivably be developed as a novel dengue vector control strategy, referring to previously documented direct toxicity on the larval stage. But this will require further research on CB waste effects on non-target organisms including humans. PMID:24239749

  8. Transcript Profiles of Two Wheat Lipid Transfer Protein-encoding Genes are Altered During Attach by Hessian Fly Larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘GeneCalling’, an mRNA profiling technology, was used to identify a candidate lipid transfer protein (LTP) sequence that showed decreased mRNA abundance in wheat (Triticum aestivum L. em Thell) plants following attack by virulent Hessian fly (Mayetiola destructor Say) larvae (compatible interaction)...

  9. Bromeliad-inhabiting mosquitoes in an urban botanical garden of dengue endemic Rio de Janeiro--are bromeliads productive habitats for the invasive vectors Aedes aegypti and Aedes albopictus?

    PubMed

    Mocellin, Márcio Goulart; Simões, Taynãna César; Nascimento, Teresa Fernandes Silva do; Teixeira, Maria Lucia França; Lounibos, Leon Philip; Oliveira, Ricardo Lourenço de

    2009-12-01

    Immatures of both Aedes aegypti and Aedes albopictus have been found in water-holding bromeliad axils in Brazil. Removal of these plants or their treatment with insecticides in public and private gardens have been undertaken during dengue outbreaks in Brazil despite uncertainty as to their importance as productive habitats for dengue vectors. From March 2005-February 2006, we sampled 120 randomly selected bromeliads belonging to 10 species in a public garden less than 200 m from houses in a dengue-endemic neighborhood in Rio de Janeiro. A total of 2,816 mosquito larvae and pupae was collected, with an average of 5.87 immatures per plant per collection. Culex (Microculex) pleuristriatus and Culex spp of the Ocellatus Group were the most abundant culicid species, found in all species of bromeliads; next in relative abundance were species of the genus Wyeomyia. Only two individuals of Ae. aegypti (0.07%) and five of Ae. albopictus(0.18%) were collected from bromeliads. By contrast, immatures of Ae. aegypti were found in manmade containers in nearly 5% of nearby houses. These results demonstrate that bromeliads are not important producers of Ae. aegypti and Ae. albopictus and, hence, should not be a focus for dengue control. However, the results of this study of only one year in a single area may not represent outcomes in other urban localities where bromeliads, Ae. aegypti and dengue coincide in more disturbed habitats. PMID:20140379

  10. Larvicidal Potential of the Halogenated Sesquiterpene (+)-Obtusol, Isolated from the Alga Laurencia dendroidea J. Agardh (Ceramiales: Rhodomelaceae), against the Dengue Vector Mosquito Aedes aegypti (Linnaeus) (Diptera: Culicidae).

    PubMed

    Salvador-Neto, Orlando; Gomes, Simone Azevedo; Soares, Angélica Ribeiro; Machado, Fernanda Lacerda da Silva; Samuels, Richard Ian; Nunes da Fonseca, Rodrigo; Souza-Menezes, Jackson; Moraes, Jorge Luiz da Cunha; Campos, Eldo; Mury, Flávia Borges; Silva, José Roberto

    2016-02-01

    Dengue is considered a serious public health problem in many tropical regions of the world including Brazil. At the moment, there is no viable alternative to reduce dengue infections other than controlling the insect vector, Aedes aegypti Linnaeus. In the continuing search for new sources of chemicals targeted at vector control, natural products are a promising alternative to synthetic pesticides. In our work, we investigated the toxicity of a bioactive compound extracted from the red alga Laurencia dendroidea J. Agardh. The initial results demonstrated that crude extracts, at a concentration of 5 ppm, caused pronounced mortality of second instar A. aegypti larvae. Two molecules, identified as (-)-elatol and (+)-obtusol were subsequently isolated from crude extract and further evaluated. Assays with (-)-elatol showed moderate larvicidal activity, whereas (+)-obtusol presented higher toxic activity than (-)-elatol, with a LC50 value of 3.5 ppm. Histological analysis of the larvae exposed to (+)-obtusol revealed damage to the intestinal epithelium. Moreover, (+)-obtusol-treated larvae incubated with 2 µM CM-H₂DCFDA showed the presence of reactive oxygen species, leading us to suggest that epithelial damage might be related to redox imbalance. These results demonstrate the potential of (+)-obtusol as a larvicide for use against A. aegypti and the possible mode of action of this compound. PMID:26821032

  11. Larvicidal Potential of the Halogenated Sesquiterpene (+)-Obtusol, Isolated from the Alga Laurencia dendroidea J. Agardh (Ceramiales: Rhodomelaceae), against the Dengue Vector Mosquito Aedes aegypti (Linnaeus) (Diptera: Culicidae)

    PubMed Central

    Salvador-Neto, Orlando; Gomes, Simone Azevedo; Soares, Angélica Ribeiro; Machado, Fernanda Lacerda da Silva; Samuels, Richard Ian; Nunes da Fonseca, Rodrigo; Souza-Menezes, Jackson; Moraes, Jorge Luiz da Cunha; Campos, Eldo; Mury, Flávia Borges; Silva, José Roberto

    2016-01-01

    Dengue is considered a serious public health problem in many tropical regions of the world including Brazil. At the moment, there is no viable alternative to reduce dengue infections other than controlling the insect vector, Aedes aegypti Linnaeus. In the continuing search for new sources of chemicals targeted at vector control, natural products are a promising alternative to synthetic pesticides. In our work, we investigated the toxicity of a bioactive compound extracted from the red alga Laurencia dendroidea J. Agardh. The initial results demonstrated that crude extracts, at a concentration of 5 ppm, caused pronounced mortality of second instar A. aegypti larvae. Two molecules, identified as (−)-elatol and (+)-obtusol were subsequently isolated from crude extract and further evaluated. Assays with (−)-elatol showed moderate larvicidal activity, whereas (+)-obtusol presented higher toxic activity than (−)-elatol, with a LC50 value of 3.5 ppm. Histological analysis of the larvae exposed to (+)-obtusol revealed damage to the intestinal epithelium. Moreover, (+)-obtusol-treated larvae incubated with 2 µM CM-H2DCFDA showed the presence of reactive oxygen species, leading us to suggest that epithelial damage might be related to redox imbalance. These results demonstrate the potential of (+)-obtusol as a larvicide for use against A. aegypti and the possible mode of action of this compound. PMID:26821032

  12. An innovative forecasting and dashboard system for Malaysian dengue trends

    NASA Astrophysics Data System (ADS)

    Jamil, Jastini Mohd; Shaharanee, Izwan Nizal Mohd

    2016-08-01

    Dengue fever has been recognized in over 100 countries and 2.5 billion people live in areas where dengue is endemic. It is currently a serious arthropod-borne disease, affecting around 50-100 million people worldwide every year. Dengue fever is also prevalent in Malaysia with numerous cases including mortality recorded over the past year. In 2012, a total of 21,900 cases of dengue fever were reported with 35 deaths. Dengue, a mosquito-transmitted virus, causes a high fever accompanied by significant pain in afflicted patient and the Aedes Aegypti mosquito is the primary disease carrier. Knowing the dangerous effect of dengue fever, thus one of the solutions is to implement an innovative forecasting and dashboard system of dengue spread in Malaysia, with emphasize on an early prediction of dengue outbreak. Specifically, the model developed will provide with a valuable insight into strategically managing and controlling the future dengue epidemic. Importantly, this research will deliver the message to health policy makers such as The Ministry of Health Malaysia (MOH), practitioners, and researchers of the importance to integrate their collaboration in exploring the potential strategies in order to reduce the future burden of the increase in dengue transmission cases in Malaysia.

  13. Imported cases of dengue in Poland and their diagnosis.

    PubMed

    Pancer, Katarzyna; Szkoda, Marek Tomasz; Gut, Włodzimierz

    2014-01-01

    Infections with dengue virus are transmitted by mosquitoes. In tropical areas, it is mainly spread by Aedes aegypti while in countries with lower temperatures by Aedes albopictus. Since 2010, autochthonous cases of dengue are also reported in Europe. There are 4 serotypes of dengue virus (DENV). No correlation between clinical presentation of disease and virus type, however, were determined. Nevertheless, reinfection with different type of DENV may lead to a serious, life-threatening condition. An estimated 100 million persons are infected with dengue virus per year. Of them, approximately a half (mainly children) develop the symptoms of dengue fever (DF), dengue haemorrhagic fever (DHF) or dengue shock syndrome (DSS). Fatality is high in case of severe dengue. Dengue is a serious condition provided there is a presence of IgG antibodies directed against antigens of particular DENV serotypes, associated with primary infection caused by different serotype or transferred from infected mother to her child. For adequate dengue laboratory diagnosis, it is required to apply a set of various diagnostic methods. Within the family Flaviviridae, cross-reactivity is reported, which may lead to the occurrence of false-positive results. In Poland, differential diagnosis with different Flavivirus species is of special importance as it is an endemic area for tick-borne encephalitis (TBE). Thus, data regarding history of patient's immunization against TBE or yellow fever should be also taken into consideration as important in interpretation of results of serological examination. PMID:25848785

  14. Internal travel and risk of dengue transmission in Colombia.

    PubMed

    Chaparro, Pablo E; de la Hoz, Fernando; Lozano Becerra, Juan C; Repetto, Silvia A; Alba Soto, Catalina D

    2014-09-01

    Human behavior plays a key role in the dynamics of dengue transmission. However, research on the relationship between human movement and dengue transmission within endemic countries is limited. From January 2008 to December 2011, the authors of this study conducted a retrospective analysis of imported dengue infections in Bogotá, Colombia. Bogotá is a vector-transmission-free city that is also the capital district and most populated municipality in Colombia. The study revealed that 1) Bogotá inhabitants acquired dengue infection in diverse localities throughout the country but the largest proportion of cases (35.6%) were contracted at popular tourist destinations in dengue-endemic areas near Bogotá (<200-km radius from city limits), and 2) the number of imported dengue cases increased after major holidays, a transmission pattern not seen in dengue-endemic areas, where disease incidence correlates with rainy periods. It is therefore recommended that physicians consider the effect of travel when diagnosing their patients' illnesses, especially outside dengue-endemic areas where diagnosis of the disease can be challenging due to its nonspecific symptoms. The study also showed that analysis of dengue cases imported to regions free of vector transmission can generate an evidence-based model for characterizing the impact of human movement on the spread of diseases like dengue in countries where they are endemic. PMID:25418771

  15. Cost of Dengue Vector Control Activities in Malaysia

    PubMed Central

    Packierisamy, P. Raviwharmman; Ng, Chiu-Wan; Dahlui, Maznah; Inbaraj, Jonathan; Balan, Venugopalan K.; Halasa, Yara A.; Shepard, Donald S.

    2015-01-01

    Dengue fever, an arbovirus disease transmitted by Aedes mosquitoes, has recently spread rapidly, especially in the tropical countries of the Americas and Asia-Pacific regions. It is endemic in Malaysia, with an annual average of 37,937 reported dengue cases from 2007 to 2012. This study measured the overall economic impact of dengue in Malaysia, and estimated the costs of dengue prevention. In 2010, Malaysia spent US$73.5 million or 0.03% of the country's GDP on its National Dengue Vector Control Program. This spending represented US$1,591 per reported dengue case and US$2.68 per capita population. Most (92.2%) of this spending occurred in districts, primarily for fogging. A previous paper estimated the annual cost of dengue illness in the country at US$102.2 million. Thus, the inclusion of preventive activities increases the substantial estimated cost of dengue to US$175.7 million, or 72% above illness costs alone. If innovative technologies for dengue vector control prove efficacious, and a dengue vaccine was introduced, substantial existing spending could be rechanneled to fund them. PMID:26416116

  16. Macrophage Activation Syndrome-Associated Markers in Severe Dengue.

    PubMed

    Ab-Rahman, Hasliana Azrah; Rahim, Hafiz; AbuBakar, Sazaly; Wong, Pooi-Fong

    2016-01-01

    Hemophagocytosis, a phenomenon of which activated macrophages phagocytosed hematopoietic elements was reportedly observed in severe dengue patients. In the present study, we investigated whether markers of macrophage activation syndrome (MAS) can be used as differential diagnostic markers of severe dengue. Two hundred and eight confirmed dengue patients were recruited for the study. Sandwich ELISA was used to determine serum ferritin, soluble CD163 (sCD163), and soluble CD25 (sCD25) levels. The population of circulating CD163 (mCD163) monocytes was determined using flow cytometry. Receiver operating characteristic (ROC) analysis was plotted to determine the predictive validity of the biomarkers. Serum ferritin and sCD163 were found significantly increased in severe dengue patients compared to dengue fever patients (P = 0.003). A fair area under ROC curves (AUC) at 0.72 with a significant P value of 0.004 was observed for sCD163. sCD25 and mCD163 levels were not significantly different between severe dengue and dengue fever patients. Our findings suggest that in addition to serum ferritin, sCD163 can differentiate severe dengue from that of dengue fever patients. Hence, sCD163 level can be considered for use as a predictive marker for impending severe dengue. PMID:26941578

  17. Postmortem Diagnosis of Dengue as an Epidemiological Surveillance Tool.

    PubMed

    Cavalcanti, Luciano Pamplona de Góes; Braga, Deborah Nunes de Melo; da Silva, Lívia Maria Alexandre; Aguiar, Marina Gondim; Castiglioni, Mariana; Silva-Junior, José Udevanier; Araújo, Fernanda Montenegro de Carvalho; Pereira, Renata Allana da Costa; Malta, Danielle Lima; Pompeu, Margarida Maria de Lima

    2016-01-01

    Dengue remains a problem in Brazil, and a substantial number of cases that progress to death are not diagnosed by health services. We evaluated the impact of a protocol adopted by the Coroner's Office Rocha Furtado (CO-RF) for the detection of unreported deaths from dengue in Brazil. We evaluated prospectively cases of deaths referred to the CO-RF with suspicion of dengue and those referred with other diagnosis in which the pathologists suspected dengue as the cause of death. Biological material was collected from all bodies autopsied, for which the suspected cause of death was dengue, between January 2011 and December 2012. Of the 214 bodies autopsied, 134 (62.6%) tested positive for dengue; of these cases, 121 were classified as dengue according to the World Health Organization's case definition (1997 or 2009, as appropriate). Thus, CO-RF detected 90 deaths from dengue, which were not suspected during disease progression. This CO-RF protocol, through a combined effort of the surveillance and laboratory teams, increased the detection of fatal dengue cases by 5-fold. This is the largest series of autopsies performed in cases of death related to dengue in the world to date. PMID:26598561

  18. Dengue virus–induced hemorrhage in a nonhuman primate model

    PubMed Central

    Onlamoon, Nattawat; Noisakran, Sansanee; Hsiao, Hui-Mien; Duncan, Alexander; Villinger, Francois; Ansari, Aftab A.

    2010-01-01

    Lack of a dengue hemorrhagic animal model recapitulating human dengue virus infection has been a significant impediment in advancing our understanding of the early events involved in the pathogenesis of dengue disease. In efforts to address this issue, a group of rhesus macaques were intravenously infected with dengue virus serotype 2 (strain 16 681) at 1 × 107 PFU/animal. A classic dengue hemorrhage developed 3 to 5 days after infection in 6 of 6 animals. Blood chemistry appeared to be normal with exception of creatine phosphokinase, which peaked at 7 days after infection. A modest thrombocytopenia and noticeable neutropenia concomitant with slight decrease of hemoglobin and hematocrit were registered. In addition, the concentration of D-dimer was elevated significantly. Viremia peaked at 3 to 5 days after infection followed by an inverse relationship between T and B lymphocytes and a bimodal pattern for platelet-monocytes and platelet-neutrophil aggregates. Dengue virus containing platelets engulfed by monocytes was noted at 8 or 9 days after infection. Thus, rhesus macaques inoculated intravenously with a high dose of dengue virus produced dengue hemorrhage, which may provide a unique platform to define the early events in dengue virus infection and help identify which blood components contribute to the pathogenesis of dengue disease. PMID:20042723

  19. Macrophage Activation Syndrome-Associated Markers in Severe Dengue

    PubMed Central

    Ab-Rahman, Hasliana Azrah; Rahim, Hafiz; AbuBakar, Sazaly; Wong, Pooi-Fong

    2016-01-01

    Hemophagocytosis, a phenomenon of which activated macrophages phagocytosed hematopoietic elements was reportedly observed in severe dengue patients. In the present study, we investigated whether markers of macrophage activation syndrome (MAS) can be used as differential diagnostic markers of severe dengue. Two hundred and eight confirmed dengue patients were recruited for the study. Sandwich ELISA was used to determine serum ferritin, soluble CD163 (sCD163), and soluble CD25 (sCD25) levels. The population of circulating CD163 (mCD163) monocytes was determined using flow cytometry. Receiver operating characteristic (ROC) analysis was plotted to determine the predictive validity of the biomarkers. Serum ferritin and sCD163 were found significantly increased in severe dengue patients compared to dengue fever patients (P = 0.003). A fair area under ROC curves (AUC) at 0.72 with a significant P value of 0.004 was observed for sCD163. sCD25 and mCD163 levels were not significantly different between severe dengue and dengue fever patients. Our findings suggest that in addition to serum ferritin, sCD163 can differentiate severe dengue from that of dengue fever patients. Hence, sCD163 level can be considered for use as a predictive marker for impending severe dengue. PMID:26941578

  20. Cost of Dengue Vector Control Activities in Malaysia.

    PubMed

    Packierisamy, P Raviwharmman; Ng, Chiu-Wan; Dahlui, Maznah; Inbaraj, Jonathan; Balan, Venugopalan K; Halasa, Yara A; Shepard, Donald S

    2015-11-01

    Dengue fever, an arbovirus disease transmitted by Aedes mosquitoes, has recently spread rapidly, especially in the tropical countries of the Americas and Asia-Pacific regions. It is endemic in Malaysia, with an annual average of 37,937 reported dengue cases from 2007 to 2012. This study measured the overall economic impact of dengue in Malaysia, and estimated the costs of dengue prevention. In 2010, Malaysia spent US$73.5 million or 0.03% of the country's GDP on its National Dengue Vector Control Program. This spending represented US$1,591 per reported dengue case and US$2.68 per capita population. Most (92.2%) of this spending occurred in districts, primarily for fogging. A previous paper estimated the annual cost of dengue illness in the country at US$102.2 million. Thus, the inclusion of preventive activities increases the substantial estimated cost of dengue to US$175.7 million, or 72% above illness costs alone. If innovative technologies for dengue vector control prove efficacious, and a dengue vaccine was introduced, substantial existing spending could be rechanneled to fund them. PMID:26416116

  1. Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality.

    PubMed

    Alkhaibari, Abeer M; Carolino, Aline T; Yavasoglu, Sare I; Maffeis, Thierry; Mattoso, Thalles C; Bull, James C; Samuels, Richard I; Butt, Tariq M

    2016-07-01

    Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world's population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti larvae

  2. Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality

    PubMed Central

    Alkhaibari, Abeer M.; Carolino, Aline T.; Yavasoglu, Sare I.; Maffeis, Thierry; Mattoso, Thalles C.; Bull, James C.; Samuels, Richard I.; Butt, Tariq M.

    2016-01-01

    Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world’s population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti

  3. The relationship of interacting immunological components in dengue pathogenesis

    PubMed Central

    2009-01-01

    The World Health Organization (WHO) estimates that there are over 50 million cases of dengue fever reported annually and approximately 2.5 billion people are at risk. Mild dengue fever presents with headache, fever, rash, myalgia, osteogenic pain, and lethargy. Severe disease can manifest as dengue shock syndrome (DSS) or dengue hemorrhagic fever (DHF). Symptoms of DSS/DHF are leukopenia, low blood volume and pressure encephalitis, cold and sweaty skin, gastrointestinal bleeding, and spontaneous bleeding from gums and nose. Currently, there are no therapeutics available beyond supportive care and untreated complicated dengue fever can have a 50% mortality rate. According to WHO DSS/DHF is the leading cause of childhood mortality in some Asian countries. Dendritic cells are professional antigen presenting cells that are primary targets in a dengue infection. Dengue binds to Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin (DC-SIGN). DC-SIGN has a high affinity for ICAM3 which is expressed in activating T-cells. Previous studies have demonstrated an altered T-cell phenotype expressed in dengue infected patients that could be potentially mediated by dengue-infected DCs. Dengue is enhanced by three interacting components of the immune system. Dengue begins by infecting dendritic cells which in immature dendritic cells is mediated by DC-SIGN. In mature dendritic cells, antibodies can enhance dengue infection via Fc receptors. Downstream of dendritic cells T-cells become activated and generate the very cytokines implicated in vascular leak and shock in addition to activating effector cells. Both the virus and the antibodies are involved in release of complement and anaphylatoxins which can cause or exacerbate DHF/DSS. These systems are inextricable and strongly associated with dengue pathogenesis. PMID:19941667

  4. Directional flow sensing by passively stable larvae.

    PubMed

    Fuchs, Heidi L; Christman, Adam J; Gerbi, Gregory P; Hunter, Elias J; Diez, F Javier

    2015-09-01

    Mollusk larvae have a stable, velum-up orientation that may influence how they sense and react to hydrodynamic signals applied in different directions. Directional sensing abilities and responses could affect how a larva interacts with anisotropic fluid motions, including those in feeding currents and in boundary layers encountered during settlement. Oyster larvae (Crassostrea virginica) were exposed to simple shear in a Couette device and to solid-body rotation in a single rotating cylinder. Both devices were operated in two different orientations, one with the axis of rotation parallel to the gravity vector, and one with the axis perpendicular. Larvae and flow were observed simultaneously with near-infrared particle-image velocimetry, and behavior was quantified as a response to strain rate, vorticity and centripetal acceleration. Only flows rotating about a horizontal axis elicited the diving response observed previously for oyster larvae in turbulence. The results provide strong evidence that the turbulence-sensing mechanism relies on gravity-detecting organs (statocysts) rather than mechanosensors (cilia). Flow sensing with statocysts sets oyster larvae apart from zooplankters such as copepods and protists that use external mechanosensors in sensing spatial velocity gradients generated by prey or predators. Sensing flow-induced changes in orientation, rather than flow deformation, would enable more efficient control of vertical movements. Statocysts provide larvae with a mechanism of maintaining their upward swimming when rotated by vortices and initiating dives toward the seabed in response to the strong turbulence associated with adult habitats. PMID:26333930

  5. Behavior of Settling Marine Larvae in Flow

    NASA Astrophysics Data System (ADS)

    Hernandez, J.; Koehl, M. A.

    2012-12-01

    Many bottom-dwelling marine animals produce microscopic larvae that are dispersed by ambient water currents. These larvae can only recruit to habitats on which they have landed if they can resist being washed away by ambient water flow. We found that larvae on marine surfaces do not experience steady water flow, but rather are exposed to brief pulses of water movement as turbulent eddies sweep across them. We made video recordings of larvae of the tube worm, Hydroides elegans, (important members of the community of organisms growing on docks and ships) on surfaces subjected to measured realistic flow pulses to study factors that might affect their dislodgement from surfaces in nature. We found that the response of a larva of H. elegans to a realistic pulse of water flow depended on its behavior at the time of the pulse and on its recent history of exposure to flow pulses, and that stationary larvae were less likely than locomoting larvae to be blown away when hit by the first pulse of water flow.; ;

  6. Multiobjective Genetic Algorithm applied to dengue control.

    PubMed

    Florentino, Helenice O; Cantane, Daniela R; Santos, Fernando L P; Bannwart, Bettina F

    2014-12-01

    Dengue fever is an infectious disease caused by a virus of the Flaviridae family and transmitted to the person by a mosquito of the genus Aedes aegypti. This disease has been a global public health problem because a single mosquito can infect up to 300 people and between 50 and 100 million people are infected annually on all continents. Thus, dengue fever is currently a subject of research, whether in the search for vaccines and treatments for the disease or efficient and economical forms of mosquito control. The current study aims to study techniques of multiobjective optimization to assist in solving problems involving the control of the mosquito that transmits dengue fever. The population dynamics of the mosquito is studied in order to understand the epidemic phenomenon and suggest strategies of multiobjective programming for mosquito control. A Multiobjective Genetic Algorithm (MGA_DENGUE) is proposed to solve the optimization model treated here and we discuss the computational results obtained from the application of this technique. PMID:25230238

  7. Dengue: recent past and future threats.

    PubMed

    Rogers, David J

    2015-04-01

    This article explores four key questions about statistical models developed to describe the recent past and future of vector-borne diseases, with special emphasis on dengue: (1) How many variables should be used to make predictions about the future of vector-borne diseases? (2) Is the spatial resolution of a climate dataset an important determinant of model accuracy? (3) Does inclusion of the future distributions of vectors affect predictions of the futures of the diseases they transmit? (4) Which are the key predictor variables involved in determining the distributions of vector-borne diseases in the present and future? Examples are given of dengue models using one, five or 10 meteorological variables and at spatial resolutions of from one-sixth to two degrees. Model accuracy is improved with a greater number of descriptor variables, but is surprisingly unaffected by the spatial resolution of the data. Dengue models with a reduced set of climate variables derived from the HadCM3 global circulation model predictions for the 1980s are improved when risk maps for dengue's two main vectors (Aedes aegypti and Aedes albopictus) are also included as predictor variables; disease and vector models are projected into the future using the global circulation model predictions for the 2020s, 2040s and 2080s. The Garthwaite-Koch corr-max transformation is presented as a novel way of showing the relative contribution of each of the input predictor variables to the map predictions. PMID:25688021

  8. Dengue Virus Genome Uncoating Requires Ubiquitination

    PubMed Central

    Byk, Laura A.; Iglesias, Néstor G.; De Maio, Federico A.; Gebhard, Leopoldo G.; Rossi, Mario

    2016-01-01

    ABSTRACT The process of genome release or uncoating after viral entry is one of the least-studied steps in the flavivirus life cycle. Flaviviruses are mainly arthropod-borne viruses, including emerging and reemerging pathogens such as dengue, Zika, and West Nile viruses. Currently, dengue virus is one of the most significant human viral pathogens transmitted by mosquitoes and is responsible for about 390 million infections every year around the world. Here, we examined for the first time molecular aspects of dengue virus genome uncoating. We followed the fate of the capsid protein and RNA genome early during infection and found that capsid is degraded after viral internalization by the host ubiquitin-proteasome system. However, proteasome activity and capsid degradation were not necessary to free the genome for initial viral translation. Unexpectedly, genome uncoating was blocked by inhibiting ubiquitination. Using different assays to bypass entry and evaluate the first rounds of viral translation, a narrow window of time during infection that requires ubiquitination but not proteasome activity was identified. In this regard, ubiquitin E1-activating enzyme inhibition was sufficient to stabilize the incoming viral genome in the cytoplasm of infected cells, causing its retention in either endosomes or nucleocapsids. Our data support a model in which dengue virus genome uncoating requires a nondegradative ubiquitination step, providing new insights into this crucial but understudied viral process. PMID:27353759

  9. T cell responses in dengue viral infections.

    PubMed

    Malavige, Gathsaurie Neelika; Ogg, Graham S

    2013-12-01

    Dengue viral infections are the commonest mosquito borne viral infection in the world, affecting more than 100 countries and 390 million individuals annually. Currently, there are no effective antiviral drugs or an effective vaccine to prevent infection. A main hurdle in developing a safe and effective vaccine has been our poor understanding of the complex nature of the protective immune response in acute dengue infection and the presence of four dengue virus (DV) serotypes that are highly homologous. The role of DV specific T cells in the pathogenesis of severe clinical disease in not clear. It has been speculated that highly cross reactive T cells for the previous infecting heterologous DV serotype, which produce pro-inflammatory cytokines, contribute to disease pathogenesis. These cross reactive T cells are believed to be suboptimal in clearing the infection with the current DV-serotype. However, other studies have shown that cross-reactive DV-specific T cells are absent or present in very low frequency during acute infection, appearing only during the convalescent period in the majority of patients. Furthermore, significant apoptosis of T cells occurs in severe acute clinical disease. Overall therefore, it is unclear what role T cells play in contributing to disease pathogenesis during acute dengue infection. Existing data have been complicated by cross-reactivity in T cells assays. These findings can now be re-evaluated in the light of novel technologies to identify serotype-specific T cell responses. PMID:24220605

  10. Dengue vaccine: come let's fight the menace.

    PubMed

    Chawla, Sumit; Sahoo, Soumya Swaroop; Singh, Inderjeet; Verma, Madhur; Gupta, Vikas; Kumari, Sneh

    2015-01-01

    Although dengue has a global distribution, the World Health Organization (WHO) South-East Asia region together with Western Pacific region bears nearly 75% of the current global disease burden. Globally, the societal burden has been estimated to be approximately 528 to 1300 disability-adjusted life years (DALY) per million to populations in endemic regions Dengue is believed to infect 50 to 100 million people worldwide a year with half a million life-threatening infections requiring hospitalization, resulting in approximately 12,500 to 25,000 deaths. Despite being known for decades and nearly half the world's population is at risk for infection with as many as 100 million cases occurring annually, the pitiable state is that we still have no antiviral drugs to treat it and no vaccines to prevent it. In recent years, however, the development of dengue vaccines has accelerated dramatically in tandem with the burgeoning dengue problem with a rejuvenated vigour. However, recent progress in molecular-based vaccine strategies, as well as a renewed commitment by the World Health Organization (WHO) to co-ordinate global efforts on vaccine development, finally provides hope that control of this serious disease may be at hand. Today, several vaccines are in various stages of advanced development, with clinical trials currently underway on 5 candidate vaccines. Trials in the most advanced stages are showing encouraging preliminary data, and the leading candidate could be licensed as early as 2015. PMID:25695523

  11. Cutaneous Larva Migrans in Early Infancy.

    PubMed

    Siddalingappa, Karjigi; Murthy, Sambasiviah Chidambara; Herakal, Kallappa; Kusuma, Marganahalli Ramachandra

    2015-01-01

    Cutaneous larva migrans or creeping eruptions is a cutaneous dermatosis caused by hookworm larvae, Ancylostoma braziliense. A 2-month-old female child presented with a progressive rash over the left buttock of 4 days duration. Cutaneous examination showed an urticarial papule progressing to erythematous, tortuous, thread-like tract extending a few centimeters from papule over the left gluteal region. A clinical diagnosis of cutaneous larva migrans was considered. Treatment with albendazole led to complete resolution, confirming the diagnosis. This is to the best of our knowledge, the youngest age at which this condition is being reported. PMID:26538729

  12. Cutaneous Larva Migrans in Early Infancy

    PubMed Central

    Siddalingappa, Karjigi; Murthy, Sambasiviah Chidambara; Herakal, Kallappa; Kusuma, Marganahalli Ramachandra

    2015-01-01

    Cutaneous larva migrans or creeping eruptions is a cutaneous dermatosis caused by hookworm larvae, Ancylostoma braziliense. A 2-month-old female child presented with a progressive rash over the left buttock of 4 days duration. Cutaneous examination showed an urticarial papule progressing to erythematous, tortuous, thread-like tract extending a few centimeters from papule over the left gluteal region. A clinical diagnosis of cutaneous larva migrans was considered. Treatment with albendazole led to complete resolution, confirming the diagnosis. This is to the best of our knowledge, the youngest age at which this condition is being reported. PMID:26538729

  13. Is dengue severity related to nutritional status?

    PubMed

    Kalayanarooj, Siripen; Nimmannitya, Suchitra

    2005-03-01

    A retrospective review of dengue patients admitted to Queen Sirikit National Institute of Child Health (previously known as Children's Hospital) from 1995 to 1999 revealed 4,532 confirmed cases of dengue infection; 80.9% were dengue hemorrhagic fever (DHF) and 19.1% were dengue fever cases (DF). Among the DHF patients; 30.6% had shock. The majority of them, 66.6%, had a normal nutritional status, while 9.3% were malnourished and 24.2% had obesity as classified by weight for age. Compared with control patients with other diagnoses (excluding HIV/AIDS patients), malnourished children had a lower risk of contracting dengue infection (odds ratio = 0.48, 95% Cl = 0.39-0.60, p = 0.000) while obese children had a greater risk of infection with dengue viruses (odds ratio = 1.96, 95% Cl = 1.55-2.5, p = 0.000). The clinical signs, symptoms and laboratory findings of dengue were almost the same among the 3 groups of malnourished, normal, and obese patients. The minor differences observed were that in obese children liver enlargement was found less often; maculopapular/convalescence rash and elevations of alanine aminotransferase were found more often. Malnourished patients had a higher risk of developing shock (37.8%) than normal (29.9%) and obese patients (30.2%) (p = 0.000). Obese patients had more unusual presentations: encephalopathy (1.3%) and associated infections (4.8%), than normal (0.5% and 2.7%) and malnourished patients (1.2% and 3.1%). Complications of fluid overload were found more in obese patients (6.5%) compared to normal (3.2%) and malnourished patients (2.1%) (p = 0.000). The case-fatality rates (CFR) in malnourished patients and obese patients were 0.5% and 0.4%, respectively, while in normal patients the CFR was 0.07%. Under and over nutrition DHF patients had either a greater risk of shock or unusual presentations and complications, which can lead to severe disease or complications and probably a higher CFR. PMID:15916044

  14. [Dengue fever: from disease to vaccination].

    PubMed

    Teyssou, R

    2009-08-01

    Dengue is a tropical disease affecting 110 countries throughout the world and placing over 3 billion people at risk of infection. According the World Health Organization 70 to 500 million persons are infected every year including 2 million who develop hemorrhagic form and 20,000 who die. Children are at highest risk for death. Due to the absence of specialized laboratories in most endemic regions and to the lack of specifici clinical presentation, the incidence of dengue and its economic costs are certainly underestimated. Dengue iscaused by an arbovirus belonging to the Flavivirus genus of the family Flaviviridae. There are four dengue virus serotypes and no cross protection between them. The disease is transmitted through the bites of mosquitoes belonging to the Aedes genus, mainly Aedes aegypti. However A. albopictus has played an important role in the spread of the disease and other species may be involved in specific locations (e.g., A. polynesiensis in the South Pacific). There is no specific treatment for dengue. Management of severe forms depends on symptomatic treatment of hemorrhagic complications and hypovolemic shock. Prevention requires control of vector mosquitoes that is difficult to implement and maintain. Dengue is a major emerging infectious disease with a heavy impact on public health. The high human and economic costs as well as the absence of specific preventive measures underscore the need to develop a vaccine. However finding and distributing such a vaccine to populations at risk is hampered by numerous obstacles. The most notable challenges standing in the way of development of a candidate vaccine are as follows: absence of an animal model, which has important implications for the preclinical development strategy; need to develop a live attenuated vaccine; existence of 4 antigenically distinct serotypes with the resulting risk of competition between vaccine strains; immunologic risks related to antibody-dependent enhancement that has been

  15. The successful induction of T-cell and antibody responses by a recombinant measles virus-vectored tetravalent dengue vaccine provides partial protection against dengue-2 infection.

    PubMed

    Hu, Hui-Mei; Chen, Hsin-Wei; Hsiao, Yu-Ju; Wu, Szu-Hsien; Chung, Han-Hsuan; Hsieh, Chun-Hsiang; Chong, Pele; Leng, Chih-Hsiang; Pan, Chien-Hsiung

    2016-07-01

    Dengue has a major impact on global public health, and the use of dengue vaccine is very limited. In this study, we evaluated the immunogenicity and protective efficacy of a dengue vaccine made from a recombinant measles virus (MV) that expresses envelope protein domain III (ED3) of dengue-1 to 4. Following immunization with the MV-vectored dengue vaccine, mice developed specific interferon-gamma and antibody responses against dengue virus and MV. Neutralizing antibodies against MV and dengue viruses were also induced, and protective levels of FRNT50 ≥ 10 to 4 serotypes of dengue viruses were detected in the MV-vectored dengue vaccine-immunized mice. In addition, specific interferon-gamma and antibody responses to dengue viruses were still induced by the MV-vectored dengue vaccine in mice that were pre-infected with MV. This finding suggests that the pre-existing immunity to MV did not block the initiation of immune responses. By contrast, mice that were pre-infected with dengue-3 exhibited no effect in terms of their antibody responses to MV and dengue viruses, but a dominant dengue-3-specific T-cell response was observed. After injection with dengue-2, a detectable but significantly lower viremia and a higher titer of anti-dengue-2 neutralizing antibodies were observed in MV-vectored dengue vaccine-immunized mice versus the vector control, suggesting that an anamnestic antibody response that provided partial protection against dengue-2 was elicited. Our results with regard to T-cell responses and the effect of pre-immunity to MV or dengue viruses provide clues for the future applications of an MV-vectored dengue vaccine. PMID:26901482

  16. Application of the dengue virus NS1 antigen rapid test for on-site detection of imported dengue cases at airports.

    PubMed

    Shu, Pei-Yun; Yang, Cheng-Fen; Kao, Jeng-Fong; Su, Chien-Ling; Chang, Shu-Fen; Lin, Chien-Chou; Yang, Wen-Chih; Shih, Hsiu; Yang, Shih-Yan; Wu, Ping-Fuai; Wu, Ho-Sheng; Huang, Jyh-Hsiung

    2009-04-01

    We used the dengue virus NS1 antigen (Ag) rapid test for on-site detection of imported dengue cases at airports. Among 22 positive cases of dengue identified from 850 patients with a fever suspected to have dengue, 17 were NS1 Ag test positive. These findings demonstrate the usefulness of the NS1 Ag rapid test in screening imported dengue cases at airports. PMID:19193828

  17. Underrecognition of Dengue during 2013 Epidemic in Luanda, Angola.

    PubMed

    Sharp, Tyler M; Moreira, Rosa; Soares, Maria José; Miguel da Costa, Lúis; Mann, Jennifer; DeLorey, Mark; Hunsperger, Elizabeth; Muñoz-Jordán, Jorge L; Colón, Candimar; Margolis, Harold S; de Caravalho, Adelaide; Tomashek, Kay M

    2015-08-01

    During the 2013 dengue epidemic in Luanda, Angola, 811 dengue rapid diagnostic test-positive cases were reported to the Ministry of Health. To better understand the magnitude of the epidemic and identify risk factors for dengue virus (DENV) infection, we conducted cluster surveys around households of case-patients and randomly selected households 6 weeks after the peak of the epidemic. Of 173 case cluster participants, 16 (9%) exhibited evidence of recent DENV infection. Of 247 random cluster participants, 25 (10%) had evidence of recent DENV infection. Of 13 recently infected participants who had a recent febrile illness, 7 (54%) had sought medical care, and 1 (14%) was hospitalized with symptoms consistent with severe dengue; however, none received a diagnosis of dengue. Behavior associated with protection from DENV infection included recent use of mosquito repellent or a bed net. These findings suggest that the 2013 dengue epidemic was larger than indicated by passive surveillance data. PMID:26196224

  18. Intravenous Immunoglobulin Responsive Persistent Thrombocytopenia after Dengue Haemorrhagic Fever

    PubMed Central

    Charaniya, Riyaz; Ghosh, Anindya; Sahoo, Ratnakar

    2016-01-01

    Dengue outbreak is common in Indian subcontinent and causes significant morbidity and mortality. Year 2015 has witnessed yet another Dengue epidemic in northern India and the number of cases this year is maximum in a decade. Dengue infection is a viral disease and there are 4 different serotypes DENV1, DENV2, DENV3 and DENV4. This year DENV2 and DENV4 have been isolated from most of the patients. Thrombocytopenia is hallmark of dengue infection and generally recovers within ten days of onset of symptoms. We report a case of dengue haemorrhagic fever in which thrombocytopenia persisted for almost a month and improved after Intravenous immunoglobulin (IVIG) administration. This is the first case where IVIG has been successfully used for treating persisting thrombocytopenia after dengue infection. PMID:27190868

  19. Intravenous Immunoglobulin Responsive Persistent Thrombocytopenia after Dengue Haemorrhagic Fever.

    PubMed

    Kumar, Prabhat; Charaniya, Riyaz; Ghosh, Anindya; Sahoo, Ratnakar

    2016-04-01

    Dengue outbreak is common in Indian subcontinent and causes significant morbidity and mortality. Year 2015 has witnessed yet another Dengue epidemic in northern India and the number of cases this year is maximum in a decade. Dengue infection is a viral disease and there are 4 different serotypes DENV1, DENV2, DENV3 and DENV4. This year DENV2 and DENV4 have been isolated from most of the patients. Thrombocytopenia is hallmark of dengue infection and generally recovers within ten days of onset of symptoms. We report a case of dengue haemorrhagic fever in which thrombocytopenia persisted for almost a month and improved after Intravenous immunoglobulin (IVIG) administration. This is the first case where IVIG has been successfully used for treating persisting thrombocytopenia after dengue infection. PMID:27190868

  20. [A case of imported Dengue fever with acute hepatitis].

    PubMed

    Suh, Sang-jun; Seo, Yeon Seok; Ahn, Jae Hong; Park, Eun Bum; Lee, Sun Jae; Sohn, Jang-uk; Um, Soon Ho

    2007-12-01

    Dengue fever is an acute febrile disease caused by the dengue virus, which belongs to the flaviviridae family, and this virus is transmitted by the bite of the mosquito Aedes aegypti. It occurs in the tropical climates of the South Pacific, Southeast Asia, India, Africa and the subtropical zone of America. Imported cases of Dengue fever and Dengue hemorrhagic fever are rapidly increasing as many Koreans are now traveling abroad. Liver injury is usually detected by laboratory investigation according to a surveillance protocol. Although liver injury by dengue virus has been described in Asia and the Pacific islands, the pathogenic mechanisms are not yet fully clarified. It is usually expressed in a self-limiting pattern and the patient has a complete recovery. We report here on a case of a young woman who presented with general weakness, nausea and significant elevation of the aminotransferase levels, and she was diagnosed with dengue fever. PMID:18159153

  1. Underrecognition of Dengue during 2013 Epidemic in Luanda, Angola

    PubMed Central

    Moreira, Rosa; Soares, Maria José; Miguel da Costa, Lúis; Mann, Jennifer; DeLorey, Mark; Hunsperger, Elizabeth; Muñoz-Jordán, Jorge L.; Colón, Candimar; Margolis, Harold S.; de Caravalho, Adelaide; Tomashek, Kay M.

    2015-01-01

    During the 2013 dengue epidemic in Luanda, Angola, 811 dengue rapid diagnostic test–positive cases were reported to the Ministry of Health. To better understand the magnitude of the epidemic and identify risk factors for dengue virus (DENV) infection, we conducted cluster surveys around households of case-patients and randomly selected households 6 weeks after the peak of the epidemic. Of 173 case cluster participants, 16 (9%) exhibited evidence of recent DENV infection. Of 247 random cluster participants, 25 (10%) had evidence of recent DENV infection. Of 13 recently infected participants who had a recent febrile illness, 7 (54%) had sought medical care, and 1 (14%) was hospitalized with symptoms consistent with severe dengue; however, none received a diagnosis of dengue. Behavior associated with protection from DENV infection included recent use of mosquito repellent or a bed net. These findings suggest that the 2013 dengue epidemic was larger than indicated by passive surveillance data. PMID:26196224

  2. TIME management by medicinal larvae.

    PubMed

    Pritchard, David I; Čeřovský, Václav; Nigam, Yamni; Pickles, Samantha F; Cazander, Gwendolyn; Nibbering, Peter H; Bültemann, Anke; Jung, Wilhelm

    2016-08-01

    Wound bed preparation (WBP) is an integral part of the care programme for chronic wounds. The acronym TIME is used in the context of WBP and describes four barriers to healing in chronic wounds; namely, dead Tissue, Infection and inflammation, Moisture imbalance and a non-migrating Edge. Larval debridement therapy (LDT) stems from observations that larvae of the blowfly Lucilia sericata clean wounds of debris. Subsequent clinical studies have proven debriding efficacy, which is likely to occur as a result of enzymatically active alimentary products released by the insect. The antimicrobial, anti-inflammatory and wound healing activities of LDT have also been investigated, predominantly in a pre-clinical context. This review summarises the findings of investigations into the molecular mechanisms of LDT and places these in context with the clinical concept of WBP and TIME. It is clear from these findings that biotherapy with L. sericata conforms with TIME, through the enzymatic removal of dead tissue and its associated biofilm, coupled with the secretion of defined antimicrobial peptides. This biotherapeutic impact on the wound serves to reduce inflammation, with an associated capacity for an indirect effect on moisture imbalance. Furthermore, larval serine proteinases have the capacity to alter fibroblast behaviour in a manner conducive to the formation of granulation tissue. PMID:26179750

  3. A Trypsin Inhibitor from Clitoria fairchildiana Cotyledons is Active Against Digestive Enzymes of Aedes aegypti Larvae.

    PubMed

    de Oliveira, Lucilene O; Fernandes, Kátia V S; Pádua, Dayanni de Souza; Carvalho, André de O; Lemos, Francisco J A; Gomes, Valdirene M; Oliveira, Antônia E A; Ferreira, André T da Silva; Perales, Jonas

    2015-01-01

    Aedes aegypti, the principal mosquito vector of yellow fever, dengue fever and chikungunya fever virus-transmitted diseases, is an insect closely associated with humans and their housing habitats. As there is no commercially available vaccine, prevention is the most suggested form of avoiding disease spreading and a number of studies are being developed in order to give support to vector control operations. The present study reports on the identification of a trypsin inhibitor isolated from cotyledons of the Clitoria fairchildiana amazonic tree seeds, which was able to reduce by 87.93 % the activity of digestive enzymes of fourth instar A. aegypti larva. A partial amino acid sequence showed strong similarity with sequences from several trypsin inhibitors already reported in the literature. The 13,000 Da isolated inhibitor was seen to be active solely against trypsin-like enzymes, neither acting on papain, α-amylase nor on other serine proteases, such as elastase, chymotrypsin or subtilisin. At least six from seven active digestive proteases from A. aegypti larvae, visualized by zymography, were severely affected soon after exposed to the inhibitor. The strong and specific action of the isolated inhibitor against trypsin digestive enzymes of this insect vector led us to believe that this protein may be a good candidate for a prospective alternative biocontrol method. PMID:26156641

  4. Effects of essential oils on Aedes aegypti larvae: alternatives to environmentally safe insecticides.

    PubMed

    Silva, W J; Dória, G A A; Maia, R T; Nunes, R S; Carvalho, G A; Blank, A F; Alves, P B; Marçal, R M; Cavalcanti, S C H

    2008-05-01

    The essential oils from leaves of Hyptis fruticosa (Lamiaceae) Salzm., H. pectinata (Lamiaceae) Poit., and Lippia gracilis (Verbenaceae) HBK were investigated for their larvicidal activity against Aedes aegypti and analyzed by GC/MS. Fifty-nine compounds, representing 91.28-98.39% of the essential oils, have been identified. A standard solution was used to make 20 mL solutions ranging from 30 to 2000 ppm. Twenty larvae between third and fourth stages were added to the essential oil solution. A mortality count was conducted 24 h after treatment. Essential oils LC50 and their confidence limits at 95% probability were calculated by the methods of Reed-Muench and Pizzi, respectively. The essential oil of Lippia gracilis showed potent insecticidal effect against Aedes aegypti larvae, the vector of dengue fever. Carvacrol and caryophyllene oxide were the main responsible for the activity of L. gracilis and H. pectinata. Minor compounds are probably acting synergistically to achieve H. fruticosa activity. PMID:17662602

  5. Silencing of P-glycoprotein increases mortality in temephos-treated Aedes aegypti larvae.

    PubMed

    Figueira-Mansur, J; Ferreira-Pereira, A; Mansur, J F; Franco, T A; Alvarenga, E S L; Sorgine, M H F; Neves, B C; Melo, A C A; Leal, W S; Masuda, H; Moreira, M F

    2013-12-01

    Re-emergence of vector-borne diseases such as dengue and yellow fever, which are both transmitted by the Aedes aegypti mosquito, has been correlated with insecticide resistance. P-glycoproteins (P-gps) are ATP-dependent efflux pumps that are involved in the transport of substrates across membranes. Some of these proteins have been implicated in multidrug resistance (MDR). In this study, we identified a putative P-glycoprotein in the Ae. aegypti database based on its significantly high identity with Anopheles gambiae, Culex quinquefasciatus, Drosophila melanogaster and human P-gps. The basal ATPase activity of ATP-binding cassette transporters in larvae was significantly increased in the presence of MDR modulators (verapamil and quinidine). An eightfold increase in Ae. aegypti P-gp (AaegP-gp) gene expression was detected in temephos-treated larvae as determined by quantitative PCR. To analyse the potential role of AaegP-gp in insecticide efflux, a temephos larvicide assay was performed in the presence of verapamil. The results showed an increase of 24% in temephos toxicity, which is in agreement with the efflux reversing effect. RNA interference (RNAi)-mediated silencing of the AaegP-gp gene caused a significant increase in temephos toxicity (57%). In conclusion, we have demonstrated for the first time in insects that insecticide-induced P-gp expression can be involved in the modulation of insecticide efflux. PMID:23980723

  6. Meteorologically Driven Simulations of Dengue Epidemics in San Juan, PR

    PubMed Central

    Morin, Cory W.; Monaghan, Andrew J.; Hayden, Mary H.; Barrera, Roberto; Ernst, Kacey

    2015-01-01

    Meteorological factors influence dengue virus ecology by modulating vector mosquito population dynamics, viral replication, and transmission. Dynamic modeling techniques can be used to examine how interactions among meteorological variables, vectors and the dengue virus influence transmission. We developed a dengue fever simulation model by coupling a dynamic simulation model for Aedes aegypti, the primary mosquito vector for dengue, with a basic epidemiological Susceptible-Exposed-Infectious-Recovered (SEIR) model. Employing a Monte Carlo approach, we simulated dengue transmission during the period of 2010–2013 in San Juan, PR, where dengue fever is endemic. The results of 9600 simulations using varied model parameters were evaluated by statistical comparison (r2) with surveillance data of dengue cases reported to the Centers for Disease Control and Prevention. To identify the most influential parameters associated with dengue virus transmission for each period the top 1% of best-fit model simulations were retained and compared. Using the top simulations, dengue cases were simulated well for 2010 (r2 = 0.90, p = 0.03), 2011 (r2 = 0.83, p = 0.05), and 2012 (r2 = 0.94, p = 0.01); however, simulations were weaker for 2013 (r2 = 0.25, p = 0.25) and the entire four-year period (r2 = 0.44, p = 0.002). Analysis of parameter values from retained simulations revealed that rain dependent container habitats were more prevalent in best-fitting simulations during the wetter 2010 and 2011 years, while human managed (i.e. manually filled) container habitats were more prevalent in best-fitting simulations during the drier 2012 and 2013 years. The simulations further indicate that rainfall strongly modulates the timing of dengue (e.g., epidemics occurred earlier during rainy years) while temperature modulates the annual number of dengue fever cases. Our results suggest that meteorological factors have a time-variable influence on dengue transmission relative to other important

  7. Autochthonous case of dengue in France, October 2013.

    PubMed

    Marchand, E; Prat, C; Jeannin, C; Lafont, E; Bergmann, T; Flusin, O; Rizzi, J; Roux, N; Busso, V; Deniau, J; Noel, H; Vaillant, V; Leparc-Goffart, I; Six, C; Paty, M C

    2013-01-01

    In October 2013, autochthonous dengue fever was diagnosed in a laboratory technician in Bouches-du-Rhone, southern France, a department colonised by Aedes albopictus since 2010. After ruling out occupational contamination, we identified the likely chain of local vector-borne transmission from which the autochthonous case arose. Though limited, this second occurrence of autochthonous dengue transmission in France highlights that efforts should be continued to rapidly detect dengue virus introduction and prevent its further dissemination in France. PMID:24342514

  8. The Effects of Weather and Climate Change on Dengue

    PubMed Central

    Colón-González, Felipe J.; Fezzi, Carlo; Lake, Iain R.; Hunter, Paul R.

    2013-01-01

    Background There is much uncertainty about the future impact of climate change on vector-borne diseases. Such uncertainty reflects the difficulties in modelling the complex interactions between disease, climatic and socioeconomic determinants. We used a comprehensive panel dataset from Mexico covering 23 years of province-specific dengue reports across nine climatic regions to estimate the impact of weather on dengue, accounting for the effects of non-climatic factors. Methods and Findings Using a Generalized Additive Model, we estimated statistically significant effects of weather and access to piped water on dengue. The effects of weather were highly nonlinear. Minimum temperature (Tmin) had almost no effect on dengue incidence below 5°C, but Tmin values above 18°C showed a rapidly increasing effect. Maximum temperature above 20°C also showed an increasing effect on dengue incidence with a peak around 32°C, after which the effect declined. There is also an increasing effect of precipitation as it rose to about 550 mm, beyond which such effect declines. Rising access to piped water was related to increasing dengue incidence. We used our model estimations to project the potential impact of climate change on dengue incidence under three emission scenarios by 2030, 2050, and 2080. An increase of up to 40% in dengue incidence by 2080 was estimated under climate change while holding the other driving factors constant. Conclusions Our results indicate that weather significantly influences dengue incidence in Mexico and that such relationships are highly nonlinear. These findings highlight the importance of using flexible model specifications when analysing weather–health interactions. Climate change may contribute to an increase in dengue incidence. Rising access to piped water may aggravate dengue incidence if it leads to increased domestic water storage. Climate change may therefore influence the success or failure of future efforts against dengue. PMID:24244765

  9. Meteorologically Driven Simulations of Dengue Epidemics in San Juan, PR.

    PubMed

    Morin, Cory W; Monaghan, Andrew J; Hayden, Mary H; Barrera, Roberto; Ernst, Kacey

    2015-08-01

    Meteorological factors influence dengue virus ecology by modulating vector mosquito population dynamics, viral replication, and transmission. Dynamic modeling techniques can be used to examine how interactions among meteorological variables, vectors and the dengue virus influence transmission. We developed a dengue fever simulation model by coupling a dynamic simulation model for Aedes aegypti, the primary mosquito vector for dengue, with a basic epidemiological Susceptible-Exposed-Infectious-Recovered (SEIR) model. Employing a Monte Carlo approach, we simulated dengue transmission during the period of 2010-2013 in San Juan, PR, where dengue fever is endemic. The results of 9600 simulations using varied model parameters were evaluated by statistical comparison (r2) with surveillance data of dengue cases reported to the Centers for Disease Control and Prevention. To identify the most influential parameters associated with dengue virus transmission for each period the top 1% of best-fit model simulations were retained and compared. Using the top simulations, dengue cases were simulated well for 2010 (r2 = 0.90, p = 0.03), 2011 (r2 = 0.83, p = 0.05), and 2012 (r2 = 0.94, p = 0.01); however, simulations were weaker for 2013 (r2 = 0.25, p = 0.25) and the entire four-year period (r2 = 0.44, p = 0.002). Analysis of parameter values from retained simulations revealed that rain dependent container habitats were more prevalent in best-fitting simulations during the wetter 2010 and 2011 years, while human managed (i.e. manually filled) container habitats were more prevalent in best-fitting simulations during the drier 2012 and 2013 years. The simulations further indicate that rainfall strongly modulates the timing of dengue (e.g., epidemics occurred earlier during rainy years) while temperature modulates the annual number of dengue fever cases. Our results suggest that meteorological factors have a time-variable influence on dengue transmission relative to other important

  10. Image-based automatic recognition of larvae

    NASA Astrophysics Data System (ADS)

    Sang, Ru; Yu, Guiying; Fan, Weijun; Guo, Tiantai

    2010-08-01

    As the main objects, imagoes have been researched in quarantine pest recognition in these days. However, pests in their larval stage are latent, and the larvae spread abroad much easily with the circulation of agricultural and forest products. It is presented in this paper that, as the new research objects, larvae are recognized by means of machine vision, image processing and pattern recognition. More visional information is reserved and the recognition rate is improved as color image segmentation is applied to images of larvae. Along with the characteristics of affine invariance, perspective invariance and brightness invariance, scale invariant feature transform (SIFT) is adopted for the feature extraction. The neural network algorithm is utilized for pattern recognition, and the automatic identification of larvae images is successfully achieved with satisfactory results.

  11. What's eating you? Cutaneous larva migrans.

    PubMed

    Prickett, Kyle A; Ferringer, Tammie C

    2015-03-01

    This article provides a focused update and clinical review on cutaneous larva migrans (CLM), including atypical clinical presentations and newer management recommendations. The results and recommendations are subject to modification based on future studies. PMID:25844779

  12. First evidence of fish larvae producing sounds

    PubMed Central

    Staaterman, Erica; Paris, Claire B.; Kough, Andrew S.

    2014-01-01

    The acoustic ecology of marine fishes has traditionally focused on adults, while overlooking the early life-history stages. Here, we document the first acoustic recordings of pre-settlement stage grey snapper larvae (Lutjanus griseus). Through a combination of in situ and unprovoked laboratory recordings, we found that L. griseus larvae are acoustically active during the night, producing ‘knock’ and ‘growl’ sounds that are spectrally and temporally similar to those of adults. While the exact function and physiological mechanisms of sound production in fish larvae are unknown, we suggest that these sounds may enable snapper larvae to maintain group cohesion at night when visual cues are reduced. PMID:25274018

  13. The first epidemic of dengue hemorrhagic fever in French Guiana.

    PubMed

    Reynes, J M; Laurent, A; Deubel, V; Telliam, E; Moreau, J P

    1994-11-01

    From July 1991 to October 1992, an outbreak of dengue spread into the main urban areas of French Guiana, where 90% of the country's 114,808 inhabitants live. In mid-July 1991 dengue-2 virus was identified as being responsible for most cases, while dengue-1 virus was rarely isolated and circulated at a low level. The number of dengue cases during this period was unknown because there was no clinically based dengue surveillance system. The only available data were for the number of suspected cases as indicated by the number of patients for whom blood samples were submitted to a laboratory for dengue diagnosis. Eight hundred forty-seven of the 2,948 suspected cases were diagnosed in the laboratory as dengue cases. Six fatal cases were reported. This outbreak was marked by the appearance of the first clinical cases of dengue hemorrhagic fever (DHF) in French Guiana. Forty cases met the World Health Organization definition of clinical DHF: 32 were grade II, seven were grade III, and one was grade IV and fatal. Eighteen cases were confirmed in the laboratory and 12 were probable; there was no proof of the dengue etiology for the remaining patients. PMID:7985746

  14. Infection risk to travelers going to dengue fever endemic regions.

    PubMed

    Pongsumpun, P; Patanarapelert, K; Sriprom, M; Varamit, S; Tang, I M

    2004-03-01

    The risk of dengue virus infection to travelers visiting dengue fever endemic regions was studied through the use of mathematical modeling. A Susceptible-Infected-Recovered (SIR) model is used to describe the transmission of dengue fever (DF) in an endemic region into which tourists enter. The dynamics of a new class of human, the traveler, is incorporated into the systems of first order differential equations in the SIR describing the dynamics of the transmission in the host region. Using standard dynamic analysis methods, the numbers of travelers who become infected with the dengue virus are calculated as a function of the length of time the tourist stays in the region. PMID:15272760

  15. The growing burden of dengue in Latin America.

    PubMed

    Tapia-Conyer, Roberto; Méndez-Galván, Jorge F; Gallardo-Rincón, Héctor

    2009-10-01

    The re-emergence and subsequent failure to control dengue in Latin America provides a compelling illustration of the clinical, political and socio-economic challenges to eradicating dengue across the world. Insufficient political commitment, inadequate financial resources and increased urbanisation have contributed to the re-emergence and dramatic increase in dengue fever and dengue haemorrhagic fever in all 19 Latin American countries previously certified as free of Aedes aegypti. Difficulties with diagnosis, asymptomatic infection and the lack of effective surveillance systems account for the discrepancies between antibody prevalence against dengue and reported cases. Accurate incidence data and appreciation of the economic impact of dengue at regional, national and international levels are essential to securing political and economic commitment for dengue control efforts as well as increased scientific and social awareness. Environmental control efforts require an integrated and systematic approach at both the national and community level, while successful introduction of a dengue vaccine will require an educational programme that clearly communicates the cost-effectiveness and desirability of this interventional measure. In addition, countries must anticipate their national regulatory requirements, and vaccination strategies should be optimised according to the dengue epidemiology of each country. A broad scope is required to finance vaccination programmes to ensure individual countries' monetary shortcomings are addressed. PMID:19800563

  16. Agent-based modeling to simulate the dengue spread

    NASA Astrophysics Data System (ADS)

    Deng, Chengbin; Tao, Haiyan; Ye, Zhiwei

    2008-10-01

    In this paper, we introduce a novel method ABM in simulating the unique process for the dengue spread. Dengue is an acute infectious disease with a long history of over 200 years. Unlike the diseases that can be transmitted directly from person to person, dengue spreads through a must vector of mosquitoes. There is still no any special effective medicine and vaccine for dengue up till now. The best way to prevent dengue spread is to take precautions beforehand. Thus, it is crucial to detect and study the dynamic process of dengue spread that closely relates to human-environment interactions where Agent-Based Modeling (ABM) effectively works. The model attempts to simulate the dengue spread in a more realistic way in the bottom-up way, and to overcome the limitation of ABM, namely overlooking the influence of geographic and environmental factors. Considering the influence of environment, Aedes aegypti ecology and other epidemiological characteristics of dengue spread, ABM can be regarded as a useful way to simulate the whole process so as to disclose the essence of the evolution of dengue spread.

  17. Latest developments and future directions in dengue vaccines

    PubMed Central

    Thisyakorn, Chule

    2014-01-01

    Dengue is a mosquito-borne disease which is currently an expanding global health problem. The disease is caused by four closely related viruses, the dengue virus. There are no specific dengue therapeutics and prevention is currently limited to vector control measures. Development of an effective tetravalent dengue vaccine would therefore represent a major advance in the control of the disease and is considered a high public health priority. While a licensed dengue vaccine is not yet available, the scope and intensity of dengue vaccine development has increased dramatically in the last decade. The uniqueness of the dengue viruses and the spectrum of disease resulting from infection have made dengue vaccine development difficult. Several vaccine candidates are currently being evaluated in clinical studies. The candidate currently at the most advanced clinical development stage, a live-attenuated tetravalent vaccine based on chimeric yellow fever dengue virus, has progressed to phase III efficacy studies. Several other live-attenuated vaccines, as well as subunit, DNA and purified inactivated vaccine candidates, are at earlier stages of clinical development. Additional technological approaches, such as virus-vectored and virus-like particle-based vaccines, are under evaluation in preclinical studies. PMID:24757522

  18. Tetravalent DNA vaccine product as a vaccine candidate against dengue.

    PubMed

    Porter, Kevin R; Teneza-Mora, Nimfa; Raviprakash, Kanakatte

    2014-01-01

    Dengue is the most important arbovirus worldwide and is the virus that causes dengue fever and the more severe dengue hemorrhagic fever. There are four serotypes of dengue with each possessing the ability to cause disease. Developing a preventive vaccine is the most efficient and effective way to prevent these diseases, and because immunity to one serotype does not protect against the other serotypes, a vaccine must provide tetravalent protection. We used DNA immunization as a platform to develop a tetravalent vaccine. In this chapter, we describe the laboratory, regulatory, and clinical methodology for evaluating a candidate tetravalent vaccine in a Phase 1 clinical trial. PMID:24715294

  19. Seir Model for Transmission of Dengue Fever in Selangor Malaysia

    NASA Astrophysics Data System (ADS)

    Syafruddin, S.; Noorani, M. S. M.

    In this paper, we study a system of differential equations that models the population dynamics of SEIR vector transmission of dengue fever. The model studied breeding value based on the number of reported cases of dengue fever in Selangor because the state had the highest case in Malaysia. The model explains that maximum level of human infection rate of dengue fever achieved in a very short period. It is also revealed that there existed suitability result between theoretical and empirical calculation using the model. The result of SEIR model will hopefully provide an insight into the spread of dengue fever in Selangor Malaysia and basic form for modeling this area.

  20. Coral Larvae Move toward Reef Sounds

    PubMed Central

    Vermeij, Mark J. A.; Marhaver, Kristen L.; Huijbers, Chantal M.; Nagelkerken, Ivan; Simpson, Stephen D.

    2010-01-01

    Free-swimming larvae of tropical corals go through a critical life-phase when they return from the open ocean to select a suitable settlement substrate. During the planktonic phase of their life cycle, the behaviours of small coral larvae (<1 mm) that influence settlement success are difficult to observe in situ and are therefore largely unknown. Here, we show that coral larvae respond to acoustic cues that may facilitate detection of habitat from large distances and from upcurrent of preferred settlement locations. Using in situ choice chambers, we found that settling coral larvae were attracted to reef sounds, produced mainly by fish and crustaceans, which we broadcast underwater using loudspeakers. Our discovery that coral larvae can detect and respond to sound is the first description of an auditory response in the invertebrate phylum Cnidaria, which includes jellyfish, anemones, and hydroids as well as corals. If, like settlement-stage reef fish and crustaceans, coral larvae use reef noise as a cue for orientation, the alleviation of noise pollution in the marine environment may gain further urgency. PMID:20498831

  1. Coral larvae move toward reef sounds.

    PubMed

    Vermeij, Mark J A; Marhaver, Kristen L; Huijbers, Chantal M; Nagelkerken, Ivan; Simpson, Stephen D

    2010-01-01

    Free-swimming larvae of tropical corals go through a critical life-phase when they return from the open ocean to select a suitable settlement substrate. During the planktonic phase of their life cycle, the behaviours of small coral larvae (<1 mm) that influence settlement success are difficult to observe in situ and are therefore largely unknown. Here, we show that coral larvae respond to acoustic cues that may facilitate detection of habitat from large distances and from upcurrent of preferred settlement locations. Using in situ choice chambers, we found that settling coral larvae were attracted to reef sounds, produced mainly by fish and crustaceans, which we broadcast underwater using loudspeakers. Our discovery that coral larvae can detect and respond to sound is the first description of an auditory response in the invertebrate phylum Cnidaria, which includes jellyfish, anemones, and hydroids as well as corals. If, like settlement-stage reef fish and crustaceans, coral larvae use reef noise as a cue for orientation, the alleviation of noise pollution in the marine environment may gain further urgency. PMID:20498831

  2. Automated analysis of behavior in zebrafish larvae.

    PubMed

    Creton, Robbert

    2009-10-12

    Zebrafish larvae have become a popular model system to examine genetic and environmental factors that affect behavior. However, studying complex behavior in large numbers of fish larvae can be challenging. The present study describes a novel high-resolution imaging system that is unique in its ability to automatically analyze the location and orientation of zebrafish larvae in multiwell plates. The system revealed behaviors in zebrafish larvae that would have been missed by more manual approaches, including a preference to face a threatening stimulus from a distance and a clockwise orientation in a two-fish assay. The clockwise orientation of the larvae correlates with a clockwise orientation of molecular structures during early development. Larvae with reversed embryonic asymmetries display a counter-clockwise orientation in the two-fish assay, suggesting that embryonic asymmetry and chiral behavior are regulated by the same developmental mechanisms. The developed imaging techniques may be used in large-scale screens to identify genes, pharmaceuticals, and environmental toxicants that influence complex behaviors. PMID:19409932

  3. Effect of Polygonum hydropiper L. against dengue vector mosquito Aedes albopictus L.

    PubMed

    Maheswaran, Rajan; Ignacimuthu, Savarimuthu

    2014-09-01

    The present study aimed to evaluate the essential oil and an isolated compound from the leaves of Polygonum hydropiper L. against dengue vector mosquito Aedes albopictus L. The plant material was macerated and steam distilled using clavenger apparatus for oil extraction. The essential oil was tested at different concentrations of 100, 50, 25, 12.5 and 6.25 ppm concentrations against the larvae of Ae. albopictus. The isolated compound was tested for larvicidal, ovicidal, repellent, oviposition deterrent and adulticidal activities at 10, 5, 2.5, 1.25 and 0.625 ppm concentrations. The essential oil exhibited LC₅₀ values of 194.63 and 199.65 and confertifolin exhibited LC₅₀ values of 2.02 and 3.16 against the second and fourth instar larvae of Ae. albopictus, respectively. The ovicidal activity of 100% on 0- to 6-h-old eggs, repellent activity of 320.6 min, oviposition deterrent activity of 98.51% and adulticidal activity of 100% at 10 ppm concentration of confertifolin were recorded. No mortality of was observed in negative control. To the best of our knowledge, this is the first report on the potential mosquitocidal activities of confertifolin against Ae. albopictus. PMID:25033815

  4. Global situation of dengue and dengue haemorrhagic fever, and its emergence in the Americas.

    PubMed

    Pinheiro, F P; Corber, S J

    1997-01-01

    About two-thirds of the world's population live in areas infested with dengue vectors, mainly Aedes aegypti. All four dengue viruses are circulating, sometimes simultaneously, in most of these areas. It is estimated that up to 80 million persons become infected annually although marked underreporting results in the notification of much smaller figures. Currently dengue is endemic in all continents except Europe and epidemic dengue haemorrhagic fever (DHF) occurs in Asia, the Americas and some Pacific islands. The incidence of DHF is much greater in the Asian countries than in other regions. In Asian countries the disease continues to affect children predominantly although a marked increase in the number of DHF cases in people over 15 years old has been observed in the Philippines and Malaysia during recent years. In the 1990's DHF has continued to show a higher incidence in South-East Asia, particularly in Viet Nam and Thailand which together account for more than two-thirds of the DHF cases reported in Asia. However, an increase in the number of reported cases has been noted in the Philippines, Lao People's Democratic Republic, Cambodia, Myanmar, Malaysia, India, Singapore and Sri Lanka during the period 1991-1995 as compared to the preceding 5-year period. In the Americas, the emergence of epidemic DHF occurred in 1981 almost 30 years after its appearance in Asia, and its incidence is showing a marked upward trend. In 1981 Cuba reported the first major outbreak of DHF in the Americas, during which a total of 344,203 cases of dengue were notified, including 10,312 severe cases and 158 deaths. The DHF Cuban epidemic was associated with a strain of dengue-2 virus and it occurred four years after dengue-1 had been introduced in the island causing epidemics of dengue fever. Prior to this event suspected cases of DHF or fatal dengue cases had been reported by five countries but only a few of them fulfilled the WHO criteria for diagnosis of DHF. The outbreak in Cuba is

  5. Chitosan/interfering RNA nanoparticle mediated gene silencing in disease vector mosquito larvae

    PubMed Central

    Zhang, Xin; Mysore, Keshava; Flannery, Ellen; Michel, Kristin; Severson, David W.; Zhu, Kun Yan

    2015-01-01

    SHORT ABSTRACT Here we describe a procedure for inhibiting gene function in disease vector mosquitoes through the use of chitosan/interfering RNA nanoparticles that are ingested by larvae. LONG ABSTRACT Vector mosquitoes inflict more human suffering than any other organism—and kill more than one million people each year. The mosquito genome projects facilitated research in new facets of mosquito biology, including functional genetic studies in the primary African malaria vector Anopheles gambiae and the dengue and yellow fever vector Aedes aegypti. RNA interference- (RNAi-) mediated gene silencing has been used to target genes of interest in both of these disease vector mosquito species. Here, we describe a procedure for preparation of chitosan/interfering RNA nanoparticles that are combined with food and ingested by larvae. This technically straightforward, high-throughput, and relatively inexpensive methodology, which is compatible with long double stranded RNA (dsRNA) or small interfering RNA (siRNA) molecules, has been used for the successful knockdown of a number of different genes in A. gambiae and A. aegypti larvae. Following larval feedings, knockdown, which is verified through qRT-PCR or in situ hybridization, can persist at least through the late pupal stage. This methodology may be applicable to a wide variety of mosquito and other insect species, including agricultural pests, as well as other non-model organisms. In addition to its utility in the research laboratory, in the future, chitosan, an inexpensive, non-toxic and biodegradable polymer, could potentially be utilized in the field. PMID:25867635

  6. Transcriptional response of honey bee larvae infected with the bacterial pathogen Paenibacillus larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    American foulbrood disease of honey bees is caused by the bacterium Paenibacillus larvae. Infection occurs per os in larvae and systemic infection requires a breaching of the host peritrophic matrix and midgut epithelium. Genetic variation exists for both bacterial virulence and host resistance, and...

  7. Texas lifestyle limits transmission of dengue virus.

    PubMed

    Reiter, Paul; Lathrop, Sarah; Bunning, Michel; Biggerstaff, Brad; Singer, Daniel; Tiwari, Tejpratap; Baber, Laura; Amador, Manuel; Thirion, Jaime; Hayes, Jack; Seca, Calixto; Mendez, Jorge; Ramirez, Bernardo; Robinson, Jerome; Rawlings, Julie; Vorndam, Vance; Waterman, Stephen; Gubler, Duane; Clark, Gary; Hayes, Edward

    2003-01-01

    Urban dengue is common in most countries of the Americas, but has been rare in the United States for more than half a century. In 1999 we investigated an outbreak of the disease that affected Nuevo Laredo, Tamaulipas, Mexico, and Laredo, Texas, United States, contiguous cities that straddle the international border. The incidence of recent cases, indicated by immunoglobulin M antibody serosurvey, was higher in Nuevo Laredo, although the vector, Aedes aegypti, was more abundant in Laredo. Environmental factors that affect contact with mosquitoes, such as air-conditioning and human behavior, appear to account for this paradox. We conclude that the low prevalence of dengue in the United States is primarily due to economic, rather than climatic, factors. PMID:12533286

  8. Texas Lifestyle Limits Transmission of Dengue Virus

    PubMed Central

    Lathrop, Sarah; Bunning, Michel; Biggerstaff, Brad; Singer, Daniel; Tiwari, Tejpratap; Baber, Laura; Amador, Manuel; Thirion, Jaime; Hayes, Jack; Seca, Calixto; Mendez, Jorge; Ramirez, Bernardo; Robinson, Jerome; Rawlings, Julie; Vorndam, Vance; Waterman, Stephen; Gubler, Duane; Clark, Gary; Hayes, Edward

    2003-01-01

    Urban dengue is common in most countries of the Americas, but has been rare in the United States for more than half a century. In 1999 we investigated an outbreak of the disease that affected Nuevo Laredo, Tamaulipas, Mexico, and Laredo, Texas, United States, contiguous cities that straddle the international border. The incidence of recent cases, indicated by immunoglobulin M antibody serosurvey, was higher in Nuevo Laredo, although the vector, Aedes aegypti, was more abundant in Laredo. Environmental factors that affect contact with mosquitoes, such as air-conditioning and human behavior, appear to account for this paradox. We conclude that the low prevalence of dengue in the United States is primarily due to economic, rather than climatic, factors. PMID:12533286

  9. [The epidemiological surveillance of dengue in Mexico].

    PubMed

    Montesano-Castellanos, R; Ruiz-Matus, C

    1995-01-01

    The clinical behavior of dengue fever in Mexico has changed, now with the occurrence of hemorrhagic cases. In response to the emergence of such cases, a specific epidemiologic surveillance system has been designed and implemented. This system includes the means to monitor the factors involved in the evolution of the disease. The identification and analysis of these factors is necessary to implement prevention and control measures. This paper presents the main components and procedures of the epidemiologic surveillance system for common and hemorrhagic dengue fever in Mexico, emphasizing the usefulness of the risk approach to predict the pattern of this disease. The model includes the collaboration of a multidisciplinary group. The Epidemiologic Surveillance State Committee, coordinated by the National Health System, participates in the collection and analysis of epidemiologic data, particularly data related to the population, the individual, the vector, the viruses and the environment. PMID:8599150

  10. The Medicinal Chemistry of Dengue Virus.

    PubMed

    Behnam, Mira A M; Nitsche, Christoph; Boldescu, Veaceslav; Klein, Christian D

    2016-06-23

    The dengue virus and related flaviviruses are an increasing global health threat. In this perspective, we comment on and review medicinal chemistry efforts aimed at the prevention or treatment of dengue infections. We include target-based approaches aimed at viral or host factors and results from phenotypic screenings in cellular assay systems for viral replication. This perspective is limited to the discussion of results that provide explicit chemistry or structure-activity relationship (SAR), or appear to be of particular interest to the medicinal chemist for other reasons. The discovery and development efforts discussed here may at least partially be extrapolated toward other emerging flaviviral infections, such as West Nile virus. Therefore, this perspective, although not aimed at flaviviruses in general, should also be able to provide an overview of the medicinal chemistry of these closely related infectious agents. PMID:26771861

  11. Asymptomatic humans transmit dengue virus to mosquitoes

    PubMed Central

    Duong, Veasna; Lambrechts, Louis; Paul, Richard E.; Ly, Sowath; Lay, Rath Srey; Long, Kanya C.; Huy, Rekol; Tarantola, Arnaud; Scott, Thomas W.; Sakuntabhai, Anavaj; Buchy, Philippe

    2015-01-01

    Three-quarters of the estimated 390 million dengue virus (DENV) infections each year are clinically inapparent. People with inapparent dengue virus infections are generally considered dead-end hosts for transmission because they do not reach sufficiently high viremia levels to infect mosquitoes. Here, we show that, despite their lower average level of viremia, asymptomatic people can be infectious to mosquitoes. Moreover, at a given level of viremia, DENV-infected people with no detectable symptoms or before the onset of symptoms are significantly more infectious to mosquitoes than people with symptomatic infections. Because DENV viremic people without clinical symptoms may be exposed to more mosquitoes through their undisrupted daily routines than sick people and represent the bulk of DENV infections, our data indicate that they have the potential to contribute significantly more to virus transmission to mosquitoes than previously recognized. PMID:26553981

  12. First Experimental In Vivo Model of Enhanced Dengue Disease Severity through Maternally Acquired Heterotypic Dengue Antibodies

    PubMed Central

    Ng, Jowin Kai Wei; Zhang, Summer Lixin; Tan, Hwee Cheng; Yan, Benedict; Maria Martinez Gomez, Julia; Tan, Wei Yu; Lam, Jian Hang; Tan, Grace Kai Xin; Ooi, Eng Eong; Alonso, Sylvie

    2014-01-01

    Dengue (DEN) represents the most serious arthropod-borne viral disease. DEN clinical manifestations range from mild febrile illness to life-threatening hemorrhage and vascular leakage. Early epidemiological observations reported that infants born to DEN-immune mothers were at greater risk to develop the severe forms of the disease upon infection with any serotype of dengue virus (DENV). From these observations emerged the hypothesis of antibody-dependent enhancement (ADE) of disease severity, whereby maternally acquired anti-DENV antibodies cross-react but fail to neutralize DENV particles, resulting in higher viremia that correlates with increased disease severity. Although in vitro and in vivo experimental set ups have indirectly supported the ADE hypothesis, direct experimental evidence has been missing. Furthermore, a recent epidemiological study has challenged the influence of maternal antibodies in disease outcome. Here we have developed a mouse model of ADE where DENV2 infection of young mice born to DENV1-immune mothers led to earlier death which correlated with higher viremia and increased vascular leakage compared to DENV2-infected mice born to dengue naïve mothers. In this ADE model we demonstrated the role of TNF-α in DEN-induced vascular leakage. Furthermore, upon infection with an attenuated DENV2 mutant strain, mice born to DENV1-immune mothers developed lethal disease accompanied by vascular leakage whereas infected mice born to dengue naïve mothers did no display any clinical manifestation. In vitro ELISA and ADE assays confirmed the cross-reactive and enhancing properties towards DENV2 of the serum from mice born to DENV1-immune mothers. Lastly, age-dependent susceptibility to disease enhancement was observed in mice born to DENV1-immune mothers, thus reproducing epidemiological observations. Overall, this work provides direct in vivo demonstration of the role of maternally acquired heterotypic dengue antibodies in the enhancement of dengue

  13. Enhanced performance of an innovative dengue IgG/IgM rapid diagnostic test using an anti-dengue EDI monoclonal antibody and dengue virus antigen.

    PubMed

    Lee, Jihoo; Kim, Young-Eun; Kim, Hak-Yong; Sinniah, Mangalam; Chong, Chom-Kyu; Song, Hyun-Ok

    2015-01-01

    High levels of anti-dengue IgM or IgG can be detected using numerous rapid diagnostic tests (RDTs). However, the sensitivity and specificity of these tests are reduced by changes in envelope glycoprotein antigenicity that inevitably occur in limited expression systems. A novel RDT was designed to enhance diagnostic sensitivity. Dengue viruses cultured in animal cells were used as antigens to retain the native viral coat protein. Monoclonal antibodies (mAbs) were then developed, for the first time, against domain I of envelope glycoprotein (EDI). The anti-dengue EDI mAb was employed as a capturer, and EDII and EDIII, which are mainly involved in the induction of neutralizing antibodies in patients, were fully available to bind to anti-dengue IgM or IgG in patients. A one-way automatic blood separation device prevented reverse migration of plasma and maximize the capture of anti-dengue antibodies at the test lines. A clinical evaluation in the field proved that the novel RDT (sensitivities of 96.5% and 96.7% for anti-dengue IgM and IgG) is more effective in detecting anti-dengue antibodies than two major commercial tests (sensitivities of 54.8% and 82% for SD BIOLINE; 50.4% and 75.3% for PanBio). The innovative format of RDT can be applied to other infectious viral diseases. PMID:26655854

  14. Enhanced performance of an innovative dengue IgG/IgM rapid diagnostic test using an anti-dengue EDI monoclonal antibody and dengue virus antigen

    PubMed Central

    Lee, Jihoo; Kim, Young-Eun; Kim, Hak-Yong; Sinniah, Mangalam; Chong, Chom-Kyu; Song, Hyun-Ok

    2015-01-01

    High levels of anti-dengue IgM or IgG can be detected using numerous rapid diagnostic tests (RDTs). However, the sensitivity and specificity of these tests are reduced by changes in envelope glycoprotein antigenicity that inevitably occur in limited expression systems. A novel RDT was designed to enhance diagnostic sensitivity. Dengue viruses cultured in animal cells were used as antigens to retain the native viral coat protein. Monoclonal antibodies (mAbs) were then developed, for the first time, against domain I of envelope glycoprotein (EDI). The anti-dengue EDI mAb was employed as a capturer, and EDII and EDIII, which are mainly involved in the induction of neutralizing antibodies in patients, were fully available to bind to anti-dengue IgM or IgG in patients. A one-way automatic blood separation device prevented reverse migration of plasma and maximize the capture of anti-dengue antibodies at the test lines. A clinical evaluation in the field proved that the novel RDT (sensitivities of 96.5% and 96.7% for anti-dengue IgM and IgG) is more effective in detecting anti-dengue antibodies than two major commercial tests (sensitivities of 54.8% and 82% for SD BIOLINE; 50.4% and 75.3% for PanBio). The innovative format of RDT can be applied to other infectious viral diseases. PMID:26655854

  15. Insecticide Control in a Dengue Epidemics Model

    NASA Astrophysics Data System (ADS)

    Rodrigues, Helena Sofia; Monteiro, M. Teresa T.; Torres, Delfim F. M.

    2010-09-01

    A model for the transmission of dengue disease is presented. It consists of eight mutually-exclusive compartments representing the human and vector dynamics. It also includes a control parameter (insecticide) in order to fight the mosquitoes. The main goal of this work is to investigate the best way to apply the control in order to effectively reduce the number of infected humans and mosquitoes. A case study, using data of the outbreak that occurred in 2009 in Cape Verde, is presented.

  16. Dengue: recent past and future threats

    PubMed Central

    Rogers, David J.

    2015-01-01

    This article explores four key questions about statistical models developed to describe the recent past and future of vector-borne diseases, with special emphasis on dengue: (1) How many variables should be used to make predictions about the future of vector-borne diseases?(2) Is the spatial resolution of a climate dataset an important determinant of model accuracy?(3) Does inclusion of the future distributions of vectors affect predictions of the futures of the diseases they transmit?(4) Which are the key predictor variables involved in determining the distributions of vector-borne diseases in the present and future?Examples are given of dengue models using one, five or 10 meteorological variables and at spatial resolutions of from one-sixth to two degrees. Model accuracy is improved with a greater number of descriptor variables, but is surprisingly unaffected by the spatial resolution of the data. Dengue models with a reduced set of climate variables derived from the HadCM3 global circulation model predictions for the 1980s are improved when risk maps for dengue's two main vectors (Aedes aegypti and Aedes albopictus) are also included as predictor variables; disease and vector models are projected into the future using the global circulation model predictions for the 2020s, 2040s and 2080s. The Garthwaite–Koch corr-max transformation is presented as a novel way of showing the relative contribution of each of the input predictor variables to the map predictions. PMID:25688021

  17. Toxicity effect of Delonix elata (Yellow Gulmohr) and predatory efficiency of Copepod, Mesocyclops aspericornis for the control of dengue vector, Aedes aegypti

    PubMed Central

    Vasugi, Chellamuthu; Kamalakannan, Siva; Murugan, Kadarkarai

    2013-01-01

    Objective To evaluate the toxicity, predatory efficiency of Delonix elata (D. elata) and Mesocyclops aspericornis (M. aspericornis) against dengue vector, Aedes aegypti (Ae. aegypti). Methods A mosquitocidal bioassay was conducted at different concentration of plant extract followed by WHO standard method. The probit analysis of each tested concentration and control were observed by using software SPSS 11 version package. The each tested concentration variable was assessed by DMRT method. The predatory efficiency of copepod was followed by Deo et al., 1988. The predator, M. aspericornis was observed for mortality, abnormalities, survival and swimming activity after 24 h treatment of plant and also predation on the mosquito larvae were observed. Results D. elata were tested for biological activity against the larvae, and pupae of Ae. aegypti. Significant mortality effects were observed in each life stage. The percentage of mortality was 100% in first and second instars whereas 96%, 92% in third and fourth instars. Fitted probit-mortality curves for larvae indicated the median and 90% lethal concentrations of D. elata for instars 1-4 to be 4.91 (8.13), 5.16 (8.44), 5.95 (7.76) and 6.87 (11.23), respectively. The results indicate that leaf extract exhibits significant biological activity against life stages. The present study revealed that D. elata is potentially important in the control of Ae. aegypti. Similar studies were conducted for predatory efficiency of Copepod, M. aspericornis against mosquito vector Ae. Aegypti. This study reported that the predatory copepod fed on 39% and 25% in I and III instar larvae of mosquito and in combined treatment of D. elata and copepod maximum control of mosquito larval states and at 83%, 80%, 75% and 53% in I, II, III and IV instars, respectively. Conclusions The combined action of plant extract and predatory copepod to effectively control mosquito population and reduce the dengue transmitting diseases.

  18. Dengue in Malaysia: Factors Associated with Dengue Mortality from a National Registry

    PubMed Central

    Suli, Zailiza; Mudin, Rose Nani; Goh, Pik Pin; Chinna, Karuthan

    2016-01-01

    Background The increasing incidence and geographical distribution of dengue has had significant impact on global healthcare services and resources. This study aimed to determine the factors associated with dengue-related mortality in a cohort of Malaysian patients. Methods This was a retrospective cohort study of patients in the Malaysian National Dengue Registry of 2013. The outcome measure was dengue-related mortality. Associations between sociodemographic and clinical variables with the outcome were analysed using multivariate analysis. Results There were 43 347 cases of which 13081 were serologically confirmed. The mean age was 30.0 years (SD 15.7); 60.2% were male. The incidence of dengue increased towards the later part of the calendar year. There were 92 probable dengue mortalities, of which 41 were serologically confirmed. Multivariate analysis in those with positive serology showed that increasing age (OR 1.03; CI:1.01–1.05), persistent vomiting (OR 13.34; CI: 1.92–92.95), bleeding (OR 5.84; CI 2.17–15.70) and severe plasma leakage (OR 66.68; CI: 9.13–487.23) were associated with mortality. Factors associated with probable dengue mortality were increasing age (OR 1.04; CI:1.03–1.06), female gender (OR 1.53; CI:1.01–2.33), nausea and/or vomiting (OR 1.80; CI:1.17–2.77), bleeding (OR 3.01; CI:1.29–7.04), lethargy and/or restlessness (OR 5.97; CI:2.26–15.78), severe plasma leakage (OR 14.72; CI:1.54–140.70), and shock (OR 1805.37; CI:125.44–25982.98), in the overall study population. Conclusions Older persons and those with persistent vomiting, bleeding or severe plasma leakage, which were associated with mortality, at notification should be monitored closely and referred early if indicated. Doctors and primary care practitioners need to detect patients with dengue early before they develop these severe signs and symptoms. PMID:27336440

  19. Ecological and immunological determinants of dengue epidemics

    PubMed Central

    Wearing, Helen J.; Rohani, Pejman

    2006-01-01

    The management of infectious diseases is an increasingly important public health issue, the effective implementation of which is often complicated by difficulties in teasing apart the relative roles of extrinsic and intrinsic factors influencing transmission. Dengue, a vector-borne strain polymorphic disease, is one such infection where transmission dynamics are affected by environmental variables as well as immune-mediated serotype interactions. To understand how alternative hypotheses concerning dengue infection and transmission may explain observed multiannual cycles in disease incidence, we adopt a theoretical approach that combines both ecological and immunological mechanisms. We demonstrate that, contrary to perceived wisdom, patterns generated solely by antibody-dependent enhancement or heterogeneity in virus virulence are not consistent with serotype-specific notification data in important ways. Furthermore, to generate epidemics with the characteristic signatures observed in data, we find that a combination of seasonal variation in vector demography and, crucially, a short-lived period of cross-immunity is sufficient. We then show how understanding the persistence and eradication of dengue serotypes critically depends on the alternative assumed mechanisms. PMID:16868086

  20. Intersectoral approaches to dengue vector control.

    PubMed

    Kay, B H

    1994-12-01

    Medical entomology in the context of urban vector control, especially for dengue, can be likened to the tail of a dog. Vertically structured Aedes aegypti campaigns such as run by Gorgas and Soper earlier this century relied on sufficient legislative backing for vector control to ensure that the tail was capable of wagging the dog. Under these conditions, especially where individual rights do not intrude, vertical programs will be successful. The global expansion of dengue, dengue hemorrhagic fever and its vectors, plus growing trends towards urban/periurban living indicate a more serious scenario than at present. In 1987, the Brundtland Report: "Our Common Future" decried sectoralism in problem solving. Following the United Nations Conference on Environment and Development (UNCED) in 1992, the resulting Commission on Sustainable Development has promoted the intersectoral message of health, environment and development. The WHO/FAO/UNEP/UNCHS Panel of Experts on Environmental Management for Vector Control has promoted this for some time and is attempting to build multidisciplinary projects against urban vector borne disease. Adequate solid waste management and recycling will reduce numbers of water bearing containers infested with Aedes aegypti and provision of reliable piped water supplies will impact heavily on infested water storage containers. Both should be encouraged as viable control options. For much of the world, vertical programs have been reported as prohibitively expensive, and unacceptable intrusion on human rights and thus unsustainable in the modern economic context. However there are successful modern examples.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7844851

  1. Genetic elimination of dengue vector mosquitoes

    PubMed Central

    Wise de Valdez, Megan R.; Nimmo, Derric; Betz, John; Gong, Hong-Fei; James, Anthony A.; Alphey, Luke; Black, William C.

    2011-01-01

    An approach based on mosquitoes carrying a conditional dominant lethal gene (release of insects carrying a dominant lethal, RIDL) is being developed to control the transmission of dengue viruses by vector population suppression. A transgenic strain, designated OX3604C, of the major dengue vector, Aedes aegypti, was engineered to have a repressible female-specific flightless phenotype. This strain circumvents the need for radiation-induced sterilization, allows genetic sexing resulting in male-only releases, and permits the release of eggs instead of adult mosquitoes. OX3604C males introduced weekly into large laboratory cages containing stable target mosquito populations at initial ratios of 8.5–10∶1 OX3604C∶target eliminated the populations within 10–20 weeks. These data support the further testing of this strain in contained or confined field trials to evaluate mating competitiveness and environmental and other effects. Successful completion of the field trials should facilitate incorporation of this approach into area-wide dengue control or elimination efforts as a component of an integrated vector management strategy. PMID:21383140

  2. Findings at brain MRI in children with dengue fever and neurological symptoms.

    PubMed

    Rastogi, Ruchi; Garg, Bhavya

    2016-01-01

    Dengue is a flavivirus of the genus arbovirus with four serotypes, from DEN 1 to DEN 4. There has been an increase in incidence of dengue infection in children in the tropics and subtropics. Dengue has a variable clinical presentation, with many patients being asymptomatic. Its clinical manifestations in children vary from fever and arthralgia to life-threatening dengue hemorrhagic fever and dengue shock syndrome. We describe MRI findings in children with neurological involvement including dengue encephalopathy, acute hypoxic injury and dengue encephalitis. Dengue encephalopathy is usually secondary to multisystem derangement such as shock, hepatitis, coagulopathy and concurrent bacterial infection and is relatively common. Dengue encephalitis from direct neuronal invasion is rare. Nonspecific changes are seen on brain MRI in dengue infection. Clinical and laboratory findings as well as outcome do not necessarily correspond with brain MRI findings. PMID:26216156

  3. Concurrent Dengue and Malaria in Cayenne Hospital, French Guiana

    PubMed Central

    Matheus, Severine; Donutil, Gerd; Raulin, Olivia; Nacher, Mathieu; Morvan, Jacques

    2009-01-01

    Dengue–malaria co-infection reports are scarce. Of 1,723 consecutive febrile patients in Cayenne Hospital, 238 had dengue (174 early dengue fever cases) and 393 had malaria (371 acute malaria); 17 had both. Diagnosis of 1 of these 2 infections should not rule out testing for the other infection. PMID:19331769

  4. Climate influence on dengue epidemics in Puerto Rico.

    PubMed

    Jury, Mark R

    2008-10-01

    The variability of the insect-borne disease dengue in Puerto Rico was studied in relation to climatic variables in the period 1979-2005. Annual and monthly reported dengue cases were compared with precipitation and temperature data. Results show that the incidence of dengue in Puerto Rico was relatively constant over time despite global warming, possibly due to the offsetting effects of declining rainfall, improving health care and little change in population. Seasonal fluctuations of dengue were driven by rainfall increases from May to November. Year-to-year variability in dengue cases was positively related to temperature, but only weakly associated with local rainfall and an index of El Nino Southern Oscillation (ENSO). Climatic conditions were mapped with respect to dengue cases and patterns in high and low years were compared. During epidemics, a low pressure system east of Florida draws warm humid air over the northwestern Caribbean. Long-term trends in past observed and future projected rainfall and temperatures were studied. Rainfall has declined slowly, but temperatures in the Caribbean are rising with the influence of global warming. Thus, dengue may increase in the future, and it will be necessary to anticipate dengue epidemics using climate forecasts, to reduce adverse health impacts. PMID:18821372

  5. Dengue epidemic in Malaysia: Not a predominantly urban disease anymore

    PubMed Central

    2011-01-01

    Background Dengue infection has been an important and serious public health concern in Malaysia ever since its first reported case here in 1902. Nevertheless, to our knowledge, no nationwide investigation has been carried out to determine the actual magnitude of dengue endemicity in the Malaysian population. In this study, we describe a cross sectional seroepidemiology study of dengue IgG seroprevalence in the Malaysian adult population. Findings From 1000 subjects (35-74 years old), 91.6% subjects were found to be dengue seropositive. Age is found to be a significant risk factor associated with dengue seroposivity, where the seroprevalence increased with every 10 year increase in age. Nevertheless, gender and ethnicity did not have an effect. Interestingly, there were similar seroprevalence rates between urban and rural samples, showing that dengue is presently not confined to urban areas in Malaysia. Conclusions High dengue IgG seropositivity found in the population is an indication that dengue might be endemic in Malaysia for a long time into the future. Public awareness, proper vector control and vigilant surveillance are critical to keep the infection rates low and to prevent outbreaks. PMID:21714858

  6. The GOOD-BYE TO DENGUE GAME: Debriefing Study

    ERIC Educational Resources Information Center

    Lennon, Jeffrey L.; Coombs, David W.

    2005-01-01

    This study examined the use of postgame debriefing of a health educational board game activity on dengue fever in a Filipino student population. The debriefing used a series of specific open-ended questions, exploring students' feelings about the game and game-related questionnaires, students' perceptions of important information about dengue from…

  7. Community beliefs and practices about dengue in Puerto Rico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In spite of long-term endemicity and repeated government and private efforts, effective, sustained community participation for dengue prevention is still a challenge in Puerto Rico. This study explored differences found in interviews conducted in 2001 in attitudes toward dengue and its prevention by...

  8. Dengue in the United States of America: A Worsening Scenario?

    PubMed Central

    Rios, Maria

    2013-01-01

    Dengue is a febrile illness caused by any of the four dengue virus types (DENV-1 to -4, genus Flavivirus, family Flaviviridae) mainly transmitted by the mosquito Aedes aegypti. DENV can be transmitted by blood transfusion. Dengue has been historically present in the continental United States (US), in the state of Hawaii, and in the US insular territories in the Caribbean and the Pacific. During the second half of the 20th century, most of the cases reported in the US were imported cases brought to the country by travelers. Since 2009, cases of autochthonous dengue have been recognized in the state of Florida after 75 years of absence, followed by intensification of transmission in endemic places including the US territories of US Virgin Islands and Puerto Rico, which experienced a large dengue epidemic in 2010. The widespread distribution of dengue mosquito vectors, deficient mosquito control measures and increased frequency of DENV-infected visitors to the US coming from dengue-endemic locations or places experiencing epidemics appear to be jointly responsible for the emergence and reemergence of dengue in the US and its territories. PMID:23865061

  9. Investigation of spatiotemporal relationship between dengue fever and drought

    NASA Astrophysics Data System (ADS)

    Lee, Chieh-Han; Yu, Hwa-Lung

    2016-04-01

    Dengue Fever is a vector-borne disease that is transmitted between human and mosquitos in tropical and sub-tropical regions. Previous studies have found significant relationship between the epidemic of dengue cases and climate variables, especially temperature and precipitation. Besides, the natural phenomena (e.g., drought) are considered that significantly drop the number of dengue cases by killing vector's breeding environment. However, in Kaohsiung City, Taiwan, there are evidences that the temporal pattern of dengue is correlated to drought events. Kaohsiung City experienced two main dengue outbreaks in 2002 and 2014 that both years were confirmed with serious drought. Especially in 2014, Kaohsiung City was suffered from extremely dengue outbreak in 2014 that reported the highest number of dengue cases in the history. Otherwise, another nearby city, Tainan City, had reported the biggest outbreak in 2015. This study constructs the spatiotemporal model of dengue incidences and index of drought events (Standardized Precipitation Index, SPI) based on the distributed lag nonlinear model (DLNM). Other meteorological measures are also included in the analysis.

  10. Isolation of ancestral sylvatic dengue virus type 1, Malaysia.

    PubMed

    Teoh, Boon-Teong; Sam, Sing-Sin; Abd-Jamil, Juraina; AbuBakar, Sazaly

    2010-11-01

    Ancestral sylvatic dengue virus type 1, which was isolated from a monkey in 1972, was isolated from a patient with dengue fever in Malaysia. The virus is neutralized by serum of patients with endemic DENV-1 infection. Rare isolation of this virus suggests a limited spillover infection from an otherwise restricted sylvatic cycle. PMID:21029545

  11. Nanoparticles in the fight against mosquito-borne diseases: bioactivity of Bruguiera cylindrica-synthesized nanoparticles against dengue virus DEN-2 (in vitro) and its mosquito vector Aedes aegypti (Diptera: Culicidae).

    PubMed

    Murugan, Kadarkarai; Dinesh, Devakumar; Paulpandi, Manickam; Althbyani, Abdulaziz Dakhellah Meqbel; Subramaniam, Jayapal; Madhiyazhagan, Pari; Wang, Lan; Suresh, Udaiyan; Kumar, Palanisamy Mahesh; Mohan, Jagathish; Rajaganesh, Rajapandian; Wei, Hui; Kalimuthu, Kandasamy; Parajulee, Megha N; Mehlhorn, Heinz; Benelli, Giovanni

    2015-12-01

    Mosquitoes are blood-feeding insects serving as the most important vectors for spreading human pathogens and parasites. Dengue is a viral disease mainly vectored through the bite of Aedes mosquitoes. Its transmission has recently increased in urban and semi-urban areas of tropical and subtropical regions worldwide, becoming a major international public health concern. There is no specific treatment for dengue. Its prevention and control solely depend on effective vector control measures. Mangrove plants have been used in Indian traditional medicine for a wide array of purposes. In this research, we proposed a method for biosynthesis of antiviral and mosquitocidal silver nanoparticles (AgNP) using the aqueous extract of Bruguiera cylindrica leaves. AgNP were characterized using a variety of biophysical analyses, including UV-visible spectrophotometry, Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Bruguiera cilyndrica aqueous extract and green-synthesized AgNP were tested against the primary dengue vector Aedes aegypti. AgNP were the most effective. LC50 values ranged from 8.93 ppm (larva I) to 30.69 ppm (pupa). In vitro experiments showed that 30 μg/ml of AgNP significantly inhibited the production of dengue viral envelope (E) protein in vero cells and downregulated the expression of dengue viral E gene. Concerning nontarget effects, we observed that the predation efficiency of Carassius auratus against A. aegypti was not affected by exposure at sublethal doses of AgNP. Predation in the control was 71.81 % (larva II) and 50.43 % (larva III), while in an AgNP-treated environment, predation was boosted to 90.25 and 76.81 %, respectively. Overall, this study highlights the concrete potential of green-synthesized AgNP in the fight against dengue virus. Furthermore, B. cylindrica-synthesized AgNP can be employed at low doses to reduce larval and pupal population of A. aegypti, without detrimental

  12. Survival and swimming behavior of insecticide-exposed larvae and pupae of the yellow fever mosquito Aedes aegypti

    PubMed Central

    2014-01-01

    Background The yellow fever mosquito Aedes aegypti is essentially a container-inhabiting species that is closely associated with urban areas. This species is a vector of human pathogens, including dengue and yellow fever viruses, and its control is of paramount importance for disease prevention. Insecticide use against mosquito juvenile stages (i.e. larvae and pupae) is growing in importance, particularly due to the ever-growing problems of resistance to adult-targeted insecticides and human safety concerns regarding such use in human dwellings. However, insecticide effects on insects in general and mosquitoes in particular primarily focus on their lethal effects. Thus, sublethal effects of such compounds in mosquito juveniles may have important effects on their environmental prevalence. In this study, we assessed the survival and swimming behavior of A. aegypti 4th instar larvae (L4) and pupae exposed to increasing concentrations of insecticides. We also assessed cell death in the neuromuscular system of juveniles. Methods Third instar larvae of A. aegypti were exposed to different concentrations of azadirachtin, deltamethrin, imidacloprid and spinosad. Insect survival was assessed for 10 days. The distance swam, the resting time and the time spent in slow swimming were assessed in 4th instar larvae (L4) and pupae. Muscular and nervous cells of L4 and pupae exposed to insecticides were marked with the TUNEL reaction. The results from the survival bioassays were subjected to survival analysis while the swimming behavioral data were subjected to analyses of covariance, complemented with a regression analysis. Results All insecticides exhibited concentration-dependent effects on survival of larvae and pupae of the yellow fever mosquito. The pyrethroid deltamethrin was the most toxic insecticide followed by spinosad, imidacloprid, and azadirachtin, which exhibited low potency against the juveniles. All insecticides except azadirachtin reduced L4 swimming speed and

  13. Repair Replication and Photorepair of DNA in Larvae of DROSOPHILA MELANOGASTER

    PubMed Central

    Boyd, James B.; Presley, Jack M.

    1974-01-01

    Repair replication of DNA has been studied in first instar larvae of Drosophila melanogaster with isopycnic centrifugation techniques. Larvae were fed BUdR, FUdR, streptomycin, penicillin, and Fungazone for two to four hours prior to exposure to UV, X-rays, MMS, or EMS. Feeding was continued for four hours in the presence of 3HBUdR and DNA was isolated from whole larvae. Repair replication is stimulated by each of these agents. MMS is about 10 times as potent as EMS in stimulating repair synthesis. A dose of 200 ergs/mm2 largely saturates the level of repair replication observed after UV irradiation. Repair replication rises between 0 and 80,000 R of X-rays before falling off. Semiconservative synthesis is seriously inhibited above a dose of 40,000 R of X-rays. Photorepair has been detected as a reduction in repair synthesis resulting from post-irradiation exposure to photoreactivating light. The same treatment has no detectable effect on X-ray-stimulated repair replication. Repair replication is insensitive to the presence of caffeine or hydroxyurea during the final incubation, although semiconservative synthesis is strongly inhibited by these agents. A mixture of BUdR and 3HTdR can be used to replace 3HBUdR in detecting repair replication. PMID:4371150

  14. Seroepidemiology of Asymptomatic Dengue Virus Infection in Jeddah, Saudi Arabia

    PubMed Central

    Jamjoom, Ghazi A.; Azhar, Esam I.; Kao, Moujahid A.; Radadi, Raja M.

    2016-01-01

    BACKGROUND Although virologically confirmed dengue fever has been recognized in Jeddah, Saudi Arabia, since 1994, causing yearly outbreaks, no proper seroepidemiologic studies on dengue virus have been conducted in this region. Such studies can define the extent of infection by this virus and estimate the proportion that may result in disease. The aim of this study was to measure the seroprevalence of past dengue virus infection in healthy Saudi nationals from different areas in the city of Jeddah and to investigate demographic and environmental factors that may increase exposure to infection. METHODS Sera were collected from 1984 Saudi subjects attending primary health care centers in six districts of Jeddah. These included general patients of various ages seeking routine vaccinations, antenatal care or treatment of different illnesses excluding fever or suspected dengue. A number of blood donors were also tested. Serum samples were tested by enzyme immunoassay (EIA) for IgG antibodies to dengue viruses 1, 2, 3, 4. A questionnaire was completed for each patient recording various anthropometric data and factors that may indicate possible risk of exposure to mosquito bites and dengue infection. Patients with missing data and those who reported a history of dengue fever were excluded from analysis, resulting in a sample of 1939 patients to be analyzed. RESULTS The overall prevalence of dengue virus infection as measured by anti-dengue IgG antibodies from asymptomatic residents in Jeddah was 47.8% (927/1939) and 37% (68/184) in blood donors. Infection mostly did not result in recognizable disease, as only 19 of 1956 subjects with complete information (0.1%) reported having dengue fever in the past. Anti dengue seropositivity increased with age and was higher in males than females and in residents of communal housing and multistory buildings than in villas. One of the six districts showed significant increase in exposure rate as compared to the others. Availability of

  15. Dengue hemorrhagic fever in infants: research opportunities ignored.

    PubMed

    Halstead, Scott B; Lan, Nguyen Trong; Myint, Thein Thein; Shwe, Than Nu; Nisalak, Ananda; Kalyanarooj, Siripen; Nimmannitya, Suchitra; Soegijanto, Soegeng; Vaughn, David W; Endy, Timothy P

    2002-12-01

    The age distribution of cases of dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS) in infants under the age of 1 year are reported from Bangkok, Thailand, and for the first time for Ho Chi Minh City, Vietnam; Yangon, Myanmar; and Surabaya, Indonesia. The four dengue viruses were isolated from Thai infants, all of whom were having a primary dengue infection. Progress studying the immunologically distinct infant DHF/DSS has been limited; most contemporary research has centered on DHF/DSS accompanying secondary dengue infections. In designing research results obtained in studies on a congruent animal model, feline infectious peritonitis virus (FIPV) infections of kittens born to FIPV-immune queens should be considered. Research challenges presented by infant DHF/DSS are discussed. PMID:12498666

  16. Cavity Forming Pneumonia Due to Staphylococcus aureus Following Dengue Fever.

    PubMed

    Miyata, Nobuyuki; Yoshimura, Yukihiro; Tachikawa, Natsuo; Amano, Yuichiro; Sakamoto, Yohei; Kosuge, Youko

    2015-11-01

    While visiting Malaysia, a 22-year-old previously healthy Japanese man developed myalgia, headache, and fever, leading to a diagnosis of classical dengue fever. After improvement and returning to Japan after a five day hospitalization, he developed productive cough several days after defervescing from dengue. Computed tomography (CT) thorax scan showed multiple lung cavities. A sputum smear revealed leukocytes with phagocytized gram-positive cocci in clusters, and grew an isolate Staphylococcus aureus sensitive to semi-synthetic penicillin; he was treated successfully with ceftriaxone and cephalexin. This second reported case of pneumonia due to S. aureus occurring after dengue fever, was associated both with nosocomial exposure and might have been associated with dengue-associated immunosuppression. Clinicians should pay systematic attention to bacterial pneumonia following dengue fever to establish whether such a connection is causally associated. PMID:26304914

  17. Dengue virus: A global human threat: Review of literature

    PubMed Central

    Hasan, Shamimul; Jamdar, Sami Faisal; Alalowi, Munther; Al Ageel Al Beaiji, Sadun Mohammad

    2016-01-01

    Dengue is an acute viral illness caused by RNA virus of the family Flaviviridae and spread by Aedes mosquitoes. Presenting features may range from asymptomatic fever to dreaded complications such as hemorrhagic fever and shock. A cute-onset high fever, muscle and joint pain, myalgia, cutaneous rash, hemorrhagic episodes, and circulatory shock are the commonly seen symptoms. Oral manifestations are rare in dengue infection; however, some cases may have oral features as the only presenting manifestation. Early and accurate diagnosis is critical to reduce mortality. Although dengue virus infections are usually self-limiting, dengue infection has come up as a public health challenge in the tropical and subtropical nations. This article provide a detailed overview on dengue virus infections, varied clinical manifestations, diagnosis, differential diagnosis, and prevention and treatment. PMID:27011925

  18. Dengue virus: A global human threat: Review of literature.

    PubMed

    Hasan, Shamimul; Jamdar, Sami Faisal; Alalowi, Munther; Al Ageel Al Beaiji, Sadun Mohammad

    2016-01-01

    Dengue is an acute viral illness caused by RNA virus of the family Flaviviridae and spread by Aedes mosquitoes. Presenting features may range from asymptomatic fever to dreaded complications such as hemorrhagic fever and shock. A cute-onset high fever, muscle and joint pain, myalgia, cutaneous rash, hemorrhagic episodes, and circulatory shock are the commonly seen symptoms. Oral manifestations are rare in dengue infection; however, some cases may have oral features as the only presenting manifestation. Early and accurate diagnosis is critical to reduce mortality. Although dengue virus infections are usually self-limiting, dengue infection has come up as a public health challenge in the tropical and subtropical nations. This article provide a detailed overview on dengue virus infections, varied clinical manifestations, diagnosis, differential diagnosis, and prevention and treatment. PMID:27011925

  19. The History of Dengue Outbreaks in the Americas

    PubMed Central

    Brathwaite Dick, Olivia; San Martín, José L.; Montoya, Romeo H.; del Diego, Jorge; Zambrano, Betzana; Dayan, Gustavo H.

    2012-01-01

    Dengue is a viral disease usually transmitted by Aedes aegypti mosquitoes. Dengue outbreaks in the Americas reported in medical literature and to the Pan American Health Organization are described. The outbreak history from 1600 to 2010 was categorized into four phases: Introduction of dengue in the Americas (1600–1946); Continental plan for the eradication of the Ae. aegypti (1947–1970) marked by a successful eradication of the mosquito in 18 continental countries by 1962; Ae. aegypti reinfestation (1971–1999) caused by the failure of the mosquito eradication program; Increased dispersion of Ae. aegypti and dengue virus circulation (2000–2010) characterized by a marked increase in the number of outbreaks. During 2010 > 1.7 million dengue cases were reported, with 50,235 severe cases and 1,185 deaths. A dramatic increase in the number of outbreaks has been reported in recent years. Urgent global action is needed to avoid further disease spread. PMID:23042846

  20. Quantifying and predicting Drosophila larvae crawling phenotypes.

    PubMed

    Günther, Maximilian N; Nettesheim, Guilherme; Shubeita, George T

    2016-01-01

    The fruit fly Drosophila melanogaster is a widely used model for cell biology, development, disease, and neuroscience. The fly's power as a genetic model for disease and neuroscience can be augmented by a quantitative description of its behavior. Here we show that we can accurately account for the complex and unique crawling patterns exhibited by individual Drosophila larvae using a small set of four parameters obtained from the trajectories of a few crawling larvae. The values of these parameters change for larvae from different genetic mutants, as we demonstrate for fly models of Alzheimer's disease and the Fragile X syndrome, allowing applications such as genetic or drug screens. Using the quantitative model of larval crawling developed here we use the mutant-specific parameters to robustly simulate larval crawling, which allows estimating the feasibility of laborious experimental assays and aids in their design. PMID:27323901

  1. Quantifying and predicting Drosophila larvae crawling phenotypes

    PubMed Central

    Günther, Maximilian N.; Nettesheim, Guilherme; Shubeita, George T.

    2016-01-01

    The fruit fly Drosophila melanogaster is a widely used model for cell biology, development, disease, and neuroscience. The fly’s power as a genetic model for disease and neuroscience can be augmented by a quantitative description of its behavior. Here we show that we can accurately account for the complex and unique crawling patterns exhibited by individual Drosophila larvae using a small set of four parameters obtained from the trajectories of a few crawling larvae. The values of these parameters change for larvae from different genetic mutants, as we demonstrate for fly models of Alzheimer’s disease and the Fragile X syndrome, allowing applications such as genetic or drug screens. Using the quantitative model of larval crawling developed here we use the mutant-specific parameters to robustly simulate larval crawling, which allows estimating the feasibility of laborious experimental assays and aids in their design. PMID:27323901

  2. Sensorimotor structure of Drosophila larva phototaxis

    PubMed Central

    Kane, Elizabeth A.; Gershow, Marc; Afonso, Bruno; Larderet, Ivan; Klein, Mason; Carter, Ashley R.; de Bivort, Benjamin L.; Sprecher, Simon G.; Samuel, Aravinthan D. T.

    2013-01-01

    The avoidance of light by fly larvae is a classic paradigm for sensorimotor behavior. Here, we use behavioral assays and video microscopy to quantify the sensorimotor structure of phototaxis using the Drosophila larva. Larval locomotion is composed of sequences of runs (periods of forward movement) that are interrupted by abrupt turns, during which the larva pauses and sweeps its head back and forth, probing local light information to determine the direction of the successive run. All phototactic responses are mediated by the same set of sensorimotor transformations that require temporal processing of sensory inputs. Through functional imaging and genetic inactivation of specific neurons downstream of the sensory periphery, we have begun to map these sensorimotor circuits into the larval central brain. We find that specific sensorimotor pathways that govern distinct light-evoked responses begin to segregate at the first relay after the photosensory neurons. PMID:24043822

  3. Arthropod larvae misidentified as parasitic worm infection.

    PubMed

    Munisamy, Sreetharan; Kilner, Rachael

    2011-01-01

    A healthy, asymptomatic man living in London, presented with seeing 'worms' in his toilet for two successive summer seasons. Repeated microscopic examination and cultures of both his faeces and urine were normal. He was empirically treated with multiple courses of antihelminthics without resolution of this problem. A sample of the worms was obtained, and positively identified as arthropod larvae under microscopic examination. These larvae do not parasitically colonise humans. It was subsequently deduced that a flying arthropod (most likely Culex pipiens mosquito) had laid eggs in standing toilet water, and the hatched larvae had been mistaken for parasitic worms. The patient was declared free of parasites and remains healthy. This case illustrates the dangers of starting empirical treatment without positive confirmation of causative organisms, which can result in unnecessary and potentially harmful treatment. PMID:22675109

  4. Preparing for introduction of a dengue vaccine: recommendations from the 1st Dengue v2V Asia-Pacific Meeting.

    PubMed

    Lam, Sai Kit; Burke, Donald; Capeding, Maria Rosario; Chong, Chee Keong; Coudeville, Laurent; Farrar, Jeremy; Gubler, Duane; Hadinegoro, Sri Rezeki; Hanna, Jeffrey; Lang, Jean; Lee, Han Lim; Leo, Yee Sin; Luong, Chan Quang; Mahoney, Richard; McBride, John; Mendez-Galvan, Jorge; Ng, Lee Ching; Nimmannitya, Suchitra; Ooi, Eng Eong; Shepard, Donald; Smit, Jaco; Teyssou, Rémy; Thomas, Laurent; Torresi, Joseph; Vasconcelos, Pedro; Wirawan, Dewa Nyoman; Yoksan, Sutee

    2011-11-28

    Infection with dengue virus is a major public health problem in the Asia-Pacific region and throughout tropical and sub-tropical regions of the world. Vaccination represents a major opportunity to control dengue and several candidate vaccines are in development. Experts in dengue and in vaccine introduction gathered for a two day meeting during which they examined the challenges inherent to the introduction of a dengue vaccine into the national immunisation programmes of countries of the Asia-Pacific. The aim was to develop a series of recommendations to reduce the delay between vaccine licensure and vaccine introduction. Major recommendations arising from the meeting included: ascertaining and publicising the full burden and cost of dengue; changing the perception of dengue in non-endemic countries to help generate global support for dengue vaccination; ensuring high quality active surveillance systems and diagnostics; and identifying sustainable sources of funding, both to support vaccine introduction and to maintain the vaccination programme. The attendees at the meeting were in agreement that with the introduction of an effective vaccine, dengue is a disease that could be controlled, and that in order to ensure a vaccine is introduced as rapidly as possible, there is a need to start preparing now. PMID:21864627

  5. An investigation into the cyclical incidence of dengue fever.

    PubMed

    Keating, J

    2001-12-01

    The purpose of this research was to review the topic of dengue fever transmission and investigate the relationship between seasonal temperature fluctuations and cyclical dengue fever incidence. Data from Puerto Rico (1988-1992) were used to test the model proposed. Dengue fever is a viral disease caused by any one of four antigenically distinct serotypes. It is transmitted by Aedes mosquitoes and infects 80 million people per year. Currently, dengue is endemic in specific tropical and subtropical regions worldwide and epidemic dengue has been reported in the Americas, Asia and some Pacific Islands. Data for Puerto Rico were collected from the NCDC/NOAA and a study conducted by Perez et al. (1994). Multivariate linear regression analysis was used to determine if a relationship exists between the monthly mean temperature lagged and the monthly incidence of dengue fever in Puerto Rico. Statistical significance was achieved and a second-order model produced an R2 of 0.71. A residual analysis reveals positive autocorrelation, thus weakening the model's power to predict monthly dengue incidence. This suggests that other forces or factors related to the history of the herd immunity, the introduction of a new serotype, or demographic transitions are also influencing the cyclical transmission of dengue fever. Case clustering information, regional dengue distributions, and population density transformations must also be obtained in order to assess the forecasting ability of this model. Additional research is needed to avoid oversimplifying the problem. Without such attempts at establishing significant correlations, dengue prevention and control will remain a formidable task for many developing and developed countries. PMID:11762885

  6. Impact of dengue virus infection and its control.

    PubMed

    Igarashi, A

    1997-08-01

    Dengue virus infection has been counted among emerging and re-emerging diseases because of (1) the increasing number of patients, (2) the expansion of epidemic areas, and (3) the appearance of severe clinical manifestation of dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS), which is often fatal if not properly treated. In the meantime, there are no effective dengue control measures: a dengue vaccine is still under development and vector control does not provide a long-lasting effect. In order to obtain direct evidence for the virulent virus theory concerning the pathogenesis of DHF/DSS, type 2 dengue virus strains isolated from patients with different clinical severities in the same epidemic area in northeast Thailand, during the same season, were comparatively sequenced. The result revealed a DF strain specific amino acid substitution from I to R in the PrM, and a DSS strain specific amino acid substitution from D to G in the NS1 gene regions, which could significantly alter the nature of these proteins. Moreover, DF strain specific nucleotide substitutions in the 3' noncoding region were predicted to alter its secondary structure. These amino acid and nucleotide substitutions in other strains isolated in different epidemic areas during other seasons, together with their biological significance, remain to be confirmed. In order to innovate dengue vector control, field tests were carried out in dengue epidemic areas in Vietnam to examine the efficacy of Olyset Net screen, which is a wide-mesh net made of polyethylene thread impregnated with permethrin. The results show that Olyset Net (1) reduced the number of principal dengue vector species, Aedes aegypti, (2) interrupted the silent transmission of dengue viruses and (3) was highly appreciated by the local people as a convenient and comfortable vector control method. This encouraging evaluation of the Olyset Net screen should be confirmed further by other tests under different settings. PMID:9348165

  7. Evaluation of dengue fever reports during an epidemic, Colombia

    PubMed Central

    Romero-Vega, Liliana; Pacheco, Oscar; de la Hoz-Restrepo, Fernando; Díaz-Quijano, Fredi Alexander

    2014-01-01

    OBJECTIVE To assess the validity of dengue fever reports and how they relate to the definition of case and severity. METHODS Diagnostic test assessment was conducted using cross-sectional sampling from a universe of 13,873 patients treated during the fifth epidemiological period in health institutions from 11 Colombian departments in 2013. The test under analyses was the reporting to the National Public Health Surveillance System, and the reference standard was the review of histories identified by active institutional search. We reviewed all histories of patients diagnosed with dengue fever, as well as a random sample of patients with febrile syndromes. The specificity and sensitivity of reports were estimated for this purpose, considering the inverse of the probability of being selected for weighting. The concordance between reporting and the findings of the active institutional search was calculated using Kappa statistics. RESULTS We included 4,359 febrile patients, and 31.7% were classified as compatible with dengue fever (17 with severe dengue fever; 461 with dengue fever and warning signs; 904 with dengue fever and no warning signs). The global sensitivity of reports was 13.2% (95%CI 10.9;15.4) and specificity was 98.4% (95%CI 97.9;98.9). Sensitivity varied according to severity: 12.1% (95%CI 9.3;14.8) for patients presenting dengue fever with no warning signs; 14.5% (95%CI 10.6;18.4) for those presenting dengue fever with warning signs, and 40.0% (95%CI 9.6;70.4) for those with severe dengue fever. Concordance between reporting and the findings of the active institutional search resulted in a Kappa of 10.1%. CONCLUSIONS Low concordance was observed between reporting and the review of clinical histories, which was associated with the low reporting of dengue fever compatible cases, especially milder cases. PMID:26039392

  8. SERUM LEVELS OF COPPER AND IRON IN DENGUE FEVER.

    PubMed

    Soundravally, Rajendiran; Sherin, Jacob; Agieshkumar, Balakrishna Pillai; Daisy, Mariya Samadanam; Cleetus, Cherupanakkal; Narayanan, Parameswaran; Kadhiravan, Tamilarasu; Sujatha, Sistla; Harichandrakumar, Kottyen Thazhath

    2015-01-01

    The role of trace elements in dengue virulence is not yet known. The present study assessed the serum levels of two micronutrients, copper and iron, in cases of dengue fever. The study involved 96 patients of whom 48 had either severe or non-severe forms of dengue (with and without warning signs), and the remaining 48 were patients with other febrile illnesses (OFI), used as controls. Serum levels of copper and iron were evaluated at admission and by the time of defervescence using commercially available kits. At admission, no difference in the level of serum copper was observed between cases and controls. In the group of dengue cases, the copper level was found to be significantly decreased in severe and non-severe cases with warning signs, compared to non-severe cases without warning signs. In contrast, by the time of defervescence the copper level was found to be increased in all dengue cases compared to OFI controls, but no difference was observed among dengue cases. Unlike OFI controls, dengue cases showed an increasing pattern of copper levels from admission until defervescence. On the other hand, no such significant differences were observed in the serum level of iron in the clinical groups, except for a decreased iron level found in severe cases, compared to non-severe dengue without warning signs. The results show that copper is associated with dengue severity and this finding emphasizes the need to investigate the involvement of trace elements in disease severity so as to improve the prognosis of dengue. PMID:26422155

  9. Evaluation of dengue fever reports during an epidemic, Colombia.

    PubMed

    Romero-Vega, Liliana; Pacheco, Oscar; de la Hoz-Restrepo, Fernando; Díaz-Quijano, Fredi Alexander

    2014-12-01

    OBJECTIVE To assess the validity of dengue fever reports and how they relate to the definition of case and severity. METHODS Diagnostic test assessment was conducted using cross-sectional sampling from a universe of 13,873 patients treated during the fifth epidemiological period in health institutions from 11 Colombian departments in 2013. The test under analyses was the reporting to the National Public Health Surveillance System, and the reference standard was the review of histories identified by active institutional search. We reviewed all histories of patients diagnosed with dengue fever, as well as a random sample of patients with febrile syndromes. The specificity and sensitivity of reports were estimated for this purpose, considering the inverse of the probability of being selected for weighting. The concordance between reporting and the findings of the active institutional search was calculated using Kappa statistics. RESULTS We included 4,359 febrile patients, and 31.7% were classified as compatible with dengue fever (17 with severe dengue fever; 461 with dengue fever and warning signs; 904 with dengue fever and no warning signs). The global sensitivity of reports was 13.2% (95%CI 10.9;15.4) and specificity was 98.4% (95%CI 97.9;98.9). Sensitivity varied according to severity: 12.1% (95%CI 9.3;14.8) for patients presenting dengue fever with no warning signs; 14.5% (95%CI 10.6;18.4) for those presenting dengue fever with warning signs, and 40.0% (95%CI 9.6;70.4) for those with severe dengue fever. Concordance between reporting and the findings of the active institutional search resulted in a Kappa of 10.1%. CONCLUSIONS Low concordance was observed between reporting and the review of clinical histories, which was associated with the low reporting of dengue fever compatible cases, especially milder cases. PMID:26039392

  10. Highly efficient production of a dengue pseudoinfectious virus

    PubMed Central

    Pang, Xiaowu; Guo, Yinhan; Zhou, Yanfei; Fu, Wenchuan; Gu, Xinbin

    2014-01-01

    Dengue is a major infectious disease that affects people living in tropical and subtropical regions around the world. The causative agents are dengue virus serotype 1, 2, 3, and 4 (DENV1, 2, 3, and 4). Developing a vaccine for dengue is a high priority for public health, but traditional methods have faced numerous obstacles due to the unique immunopathogenesis of dengue virus infection. Here, we report a novel dengue vaccine candidate based on dengue pseudoinfectious virus (PIV) produced by the incorporation of a dengue subgenomic replicon into viral particles in highly efficient packaging cells. The subgenomic replicon was constructed by deleting the capsid protein (C) gene from the dengue viral genome and optimizing the signal peptide sequence of pre-membrane protein (prM) to facilitate the formation of viral particles. Packaging cells were developed for inducible expression of a bi-protein Cpr, where the protein pr is the “pr” segment of viral protein prM that holds the protein C on the endoplasmic reticulum (ER). When the replicon was introduced into the packaging cells, protein C was released from the bi-protein Cpr by a replicon-encoded viral protease. Coordinate expression of viral structural proteins by the replicon and packaging cells led to the incorporation of the replicon into viral particle to produce PIVs. Animal tests showed that the dengue PIV vaccine was highly immunogenic and the immune response protected mice challenged with a hundred-fold LD50 inoculation of dengue virus. The method described here has the potential to be applied to vaccine development for other flaviviruses. PMID:24797700

  11. A Comparative Study of Leptospirosis and Dengue in Thai Children

    PubMed Central

    Libraty, Daniel H.; Myint, Khin S. A.; Murray, Clinton K.; Gibbons, Robert V.; Mammen, Mammen P.; Endy, Timothy P.; Li, Wenjun; Vaughn, David W.; Nisalak, Ananda; Kalayanarooj, Siripen; Hospenthal, Duane R.; Green, Sharone; Rothman, Alan L.; Ennis, Francis A.

    2007-01-01

    Background Leptospirosis is an emerging zoonosis that is often under-recognized in children and commonly confused with dengue in tropical settings. An enhanced ability to distinguish leptospirosis from dengue in children would guide clinicians and public health personnel in the appropriate use of limited healthcare resources. Methodology/Principal Findings We conducted a prospective, hospital-based, study of children with acute febrile illnesses and dengue in Thailand. Among the children without dengue, we identified those with leptospirosis using anti-leptospira IgM and microscopic agglutination titers in paired acute and convalescent blood samples. We then performed a case-control comparison of symptoms, signs, and clinical laboratory values between children with leptospirosis and dengue. In a semi-rural region of Thailand, leptospirosis accounted for 19% of the non-dengue acute febrile illnesses among children presenting during the rainy season. None of the children with leptospirosis were correctly diagnosed at the time of hospital discharge, and one third (33%) were erroneously diagnosed as dengue or scrub typhus. A predictive model to distinguish pediatric leptospirosis from dengue was generated using three variables: the absolute neutrophil count, plasma albumin, and aspartate aminotransferase levels in the first 72 hours of illness. Conclusions/Significance Unrecognized leptospirosis can be a significant cause of “dengue-like” febrile illness in children. Increased awareness of pediatric leptospirosis, and an enhanced ability to discriminate between leptospirosis and dengue early in illness, will help guide the appropriate use of healthcare resources in often resource-limited settings. PMID:18160980

  12. Platelet activation and apoptosis modulate monocyte inflammatory responses in dengue

    PubMed Central

    Hottz, Eugenio D.; Medeiros-de-Moraes, Isabel M.; Vieira-de-Abreu, Adriana; de Assis, Edson F.; Vals-de-Souza, Rogério; Castro-Faria-Neto, Hugo C.; Weyrich, Andrew S.; Zimmerman, Guy A.; Bozza, Fernando A.; Bozza, Patrícia T.

    2014-01-01

    Background Dengue is the most prevalent human arbovirus disease in the world. Dengue infection has a large spectrum of clinical manifestations from self-limited febrile illness to severe syndromes accompanied by bleeding and shock. Thrombocytopenia and vascular leak with altered cytokine profiles in plasma are features of severe dengue. Although monocytes have been recognized as important sources of cytokines in dengue, the contributions of platelet-monocyte interactions to inflammatory responses in dengue have not been addressed. Patients/Methods Patients with dengue were investigated for platelet-monocyte aggregate formation and markers of monocyte activation. Platelet-induced cytokine responses by monocytes and underlying mechanisms were also investigated in vitro. Results We observed increased levels of platelet-monocyte aggregates in blood samples from patients with dengue, especially patients with thrombocytopenia and increased vascular permeability. Moreover, the exposure of monocytes from healthy volunteers to platelets from patients with dengue induced the secretion of the cytokines IL-1β, IL-8, IL-10 and MCP-1, while the exposure to platelets from healthy volunteers only induced the secretion of MCP-1. In addition to the well-established modulation of monocyte cytokine responses by activated platelets through P-selectin binding, we found that interaction of monocytes with apoptotic platelets mediate IL-10 secretion through phosphatidylserine recognition in platelet-monocyte aggregates. Moreover, IL-10 secretion required platelet-monocyte contact but not phagocytosis. Conclusions Together, our results demonstrate that activated and apoptotic platelets aggregate with monocytes during dengue infection and signal specific cytokine responses that may contribute to the pathogenesis of dengue. PMID:25015827

  13. [Stereotactic aspiration of Spirometra mansonides larvae].

    PubMed

    Caballero, Joel; Morales, Losmill; García, Diana; Alarcón, Idelmys; Torres, Anay; Sáez, Gladys

    2015-08-01

    Brain sparganosis is a non-common parasite infection by Diphyllobothrium or Spirometra mansonoides larvae. This last one is responsible for most of the infestations in humans. We report a 19 years male patient bearer of a brain sparganosis. The patient presented with headache and left hemiparesis. CT diagnosis of right thalamic lesions was made and aspiration biopsy was performed using stereotactic system, obtaining a whole and death larvae. Histopathology confirms a CNS parasitism and it was treated initially with albendazol. ELISA test confirmed Spirometra spp. infestation. The patient developed asymptomatic with total remission of the lesions. It constitutes the second report in Cuba of brain sparganosis. PMID:26436792

  14. Dengue on islands: a Bayesian approach to understanding the global ecology of dengue viruses

    PubMed Central

    Feldstein, Leora R.; Brownstein, John S.; Brady, Oliver J.; Hay, Simon I.; Johansson, Michael A.

    2015-01-01

    Background Transmission of dengue viruses (DENV), the most common arboviral pathogens globally, is influenced by many climatic and socioeconomic factors. However, the relative contributions of these factors on a global scale are unclear. Methods We randomly selected 94 islands stratified by socioeconomic and geographic characteristics. With a Bayesian model, we assessed factors contributing to the probability of islands having a history of any dengue outbreaks and of having frequent outbreaks. Results Minimum temperature was strongly associated with suitability for DENV transmission. Islands with a minimum monthly temperature of greater than 14.8°C (95% CI: 12.4–16.6°C) were predicted to be suitable for DENV transmission. Increased population size and precipitation were associated with increased outbreak frequency, but did not capture all of the variability. Predictions for 48 testing islands verified these findings. Conclusions This analysis clarified two key components of DENV ecology: minimum temperature was the most important determinant of suitability; and endemicity was more likely in areas with high precipitation and large, but not necessarily dense, populations. Wealth and connectivity, in contrast, had no discernable effects. This model adds to our knowledge of global determinants of dengue risk and provides a basis for understanding the ecology of dengue endemicity. PMID:25771261

  15. Dengue and dengue vectors in the WHO European region: past, present, and scenarios for the future.

    PubMed

    Schaffner, Francis; Mathis, Alexander

    2014-12-01

    After 55 years of absence, dengue has re-emerged in the WHO European region both as locally transmitted sporadic cases and as an outbreak in Madeira, driven by the introduction of people infected with the virus and the invasion of the vector mosquito species Aedes aegypti and Aedes albopictus. Models predict a further spread of A albopictus, particularly under climate change conditions. Dengue transmission models suggest a low risk in Europe, but these models too rarely include transmission by A albopictus (the main established vector). Further information gaps exist with regard to the Caucasus and central Asian countries of the WHO European region. Many European countries have implemented surveillance and control measures for invasive mosquitoes, but only a few include surveillance for dengue. As long as no dengue-specific prophylaxis or therapeutics are available, integrated vector management is the most sustainable control option. The rapid elimination of newly introduced A aegypti populations should be targeted in the European region, particularly in southern Europe and the Caucasus, where the species was present for decades until the 1950s. PMID:25172160

  16. Threat of dengue fever and dengue haemorrhagic fever to Egypt from travelers.

    PubMed

    El-Bahnasawy, Mamdouh M; Khalil, Hazem H M; Morsy, Ayman T A; Morsy, Tosson A

    2011-08-01

    Dengue (DF) and dengue hemorrhagic fevers (DHF) are present in urban and suburban areas in the Americas, South-East Asia, the Eastern Mediterranean and the Western Pacific, but dengue fever is present mainly in the rural areas of Africa. Several factors have combined to produce epidemiological conditions in developing countries in the tropics and subtropics that favour viral transmission by the main mosquito vector, Aedes aegypti as the rapid population growth, rural-urban migration, inadequate basic urban infrastructure (eg. the unreliable water supply leading householders to store water in containers close to homes) and the increase in volume of solid waste, such as discarded plastic containers and other abandoned items which provide larval habitats in urban areas. Geographical expansion of the mosquito has been aided by the international commercial trade particularly in used car-tyres which easily accumulate rainwater. Increased air travel and the breakdown of vector control measures have also contributed greatly to the global burden of dengue and DH fevers. The presence of Ae. aegypti and endemicity of DF and DHF in the neighbor- ing regional countries must be in mind of the Public Health Authorities. PMID:21980768

  17. Risk factors associated with an outbreak of dengue fever/dengue haemorrhagic fever in Hanoi, Vietnam.

    PubMed

    Toan, D T T; Hoat, L N; Hu, W; Wright, P; Martens, P

    2015-06-01

    Dengue fever/dengue haemorrhagic fever (DF/DHF) appears to be emerging in Hanoi in recent years. A case-control study was performed to investigate risk factors for the development of DF/DHF in Hanoi. A total of 73 patients with DF/DHF and 73 control patients were included in the study. The risk factor analysis indicated that living in rented housing, living near uncovered sewers, and living in a house discharging sewage directly into to ponds were all significantly associated with DF/DHF. People living in rented houses were 2·2 times more at risk of DF/DHF than those living in their own homes [adjusted odds ratio (aOR) 2·2, 95% confidence interval (CI) 1·1-4·6]. People living in an unhygienic house, or in a house discharging sewage directly to the ponds were 3·4 times and 4·3 times, respectively, more likely to be associated with DF/DHF (aOR 3·4, 95% CI 1-11·7; aOR 4·3, 95% CI 1·1-16·9). These results contribute to the understanding of the dynamics of dengue transmission in Hanoi, which is needed to implement dengue prevention and control programmes effectively and efficiently. PMID:25308711

  18. A Sequence of Flushing and Drying of Breeding Habitats of Aedes aegypti (L.) Prior to the Low Dengue Season in Singapore

    PubMed Central

    Seidahmed, Osama M. E.; Eltahir, Elfatih A. B.

    2016-01-01

    In dengue-endemic areas, transmission shows both a seasonal and interannual variability. To investigate how rainfall impacts dengue seasonality in Singapore, we carried out a longitudinal survey in the Geylang neighborhood from August 2014 to August 2015. The survey comprised of twice-weekly random inspections to outdoor breeding habitats and continuous monitoring for positive ones. In addition, observations of rainstorms were collected. Out of 6824 inspected habitats, 67 contained Aedes aegypti, 11 contained Aedes albopictus and 24 contained Culex spp. The main outdoors habitat of Aedes aegypti was storm drains (54/67). We found that 80% of breeding sites in drains (43/54) were lost after intense rainstorms related to the wet phase of the Northeast monsoon (NE) between November 2014 and early January 2015. Subsequently, 95% (41/43) of these flushed drains had dried out during the dry phase of the NE in late January-February 2015. A return in the outdoor breeding of Aedes aegypti was observed after the onset of Southwest monsoon (SW) between May and August 2015. There was also a reduction in productivity of breeding habitats for larvae and pupae after the onset of the NE. In wet equatorial regions like Singapore, rainfall varies with the monsoons. A monsoon-driven sequence of flushing and drying shapes the outdoor seasonal abundance of Aedes aegypti. This finding can be used to optimize vector control strategies and better understand dengue in the context of climate change. PMID:27459322

  19. A Sequence of Flushing and Drying of Breeding Habitats of Aedes aegypti (L.) Prior to the Low Dengue Season in Singapore.

    PubMed

    Seidahmed, Osama M E; Eltahir, Elfatih A B

    2016-07-01

    In dengue-endemic areas, transmission shows both a seasonal and interannual variability. To investigate how rainfall impacts dengue seasonality in Singapore, we carried out a longitudinal survey in the Geylang neighborhood from August 2014 to August 2015. The survey comprised of twice-weekly random inspections to outdoor breeding habitats and continuous monitoring for positive ones. In addition, observations of rainstorms were collected. Out of 6824 inspected habitats, 67 contained Aedes aegypti, 11 contained Aedes albopictus and 24 contained Culex spp. The main outdoors habitat of Aedes aegypti was storm drains (54/67). We found that 80% of breeding sites in drains (43/54) were lost after intense rainstorms related to the wet phase of the Northeast monsoon (NE) between November 2014 and early January 2015. Subsequently, 95% (41/43) of these flushed drains had dried out during the dry phase of the NE in late January-February 2015. A return in the outdoor breeding of Aedes aegypti was observed after the onset of Southwest monsoon (SW) between May and August 2015. There was also a reduction in productivity of breeding habitats for larvae and pupae after the onset of the NE. In wet equatorial regions like Singapore, rainfall varies with the monsoons. A monsoon-driven sequence of flushing and drying shapes the outdoor seasonal abundance of Aedes aegypti. This finding can be used to optimize vector control strategies and better understand dengue in the context of climate change. PMID:27459322

  20. Species composition, co-occurrence, association and affinity indices of mosquito larvae (Diptera: Culicidae) in Mazandaran Province, northern Iran.

    PubMed

    Nikookar, Seyed Hassan; Azari-Hamidian, Shahyad; Fazeli-Dinan, Mahmoud; Nasab, Seyed Nouraddin Mousavi; Aarabi, Mohsen; Ziapour, Seyyed Payman; Enayati, Ahmadali

    2016-05-01

    Although considerable progress has been made in the past years in management of mosquito borne diseases such as malaria, dengue, yellow fever and West Nile fever through research in biology and ecology of the vectors, these diseases are still major threats to human health. Therefore, more research is required for better management of the diseases. This investigation provides information on the composition, co-occurrence, association and affinity indices of mosquito larvae in Mazandaran Province, northern Iran. In a large scale field study, mosquito larvae were collected from 120 sentinel sites in 16 counties in Mazandaran Province, using standard 350 ml dipper. Sampling took place monthly from May to December 2014. Collected larvae were mounted on glass slides using de Faure's medium and were diagnosed using morphological characters. Totally, 19,840 larvae were collected including three genera and 16 species from 120 larval habitats, as follows: Anopheles claviger, Anopheles hyrcanus, Anopheles maculipennis s.l., Anopheles marteri, Anopheles plumbeus, Anopheles pseudopictus, Culex pipiens, Culex tritaeniorhynchus, Culex torrentium, Culex perexiguus, Culex territans, Culex mimeticus, Culex hortensis, Culiseta annulata, Culiseta longiareolata, and Culiseta morsitans. Predominant species were Cx. pipiens and An. maculipennis s.l. which show the highest co-occurrence. The pair of species An. hyrcanus/An. pseudopictus showed significant affinity and association. High co-occurrence of the predominant species Cx. pipiens and An. maculipennis s.l. in the study area is of considerable importance in terms of vector ecology. It was also revealed that An. pseudopictus/An. hyrcanus often occur sympatrically indicating their common habitat requirements. The information may be equally important when vector control measures are considered. PMID:26805471

  1. Factors favoring houseplant container infestation with Aedes aegypti larvae in Marília, São Paulo, Brazil.

    PubMed

    Macoris, M L; Mazine, C A; Andrighetti, M T; Yasumaro, S; Silva, M E; Nelson, M J; Winch, P J

    1997-04-01

    Since reinvasion of São Paulo State by the Aedes aegypti (L.) mosquito in 1985, flower pots and vases have been important larval habitats despite educational messages focusing on their control. The objectives of this study were to characterize flower pots and vases as larval habitats with respect to the quantities present and infested, the types of plants involved, and the specific locations of the mosquito larvae; to explore local names for houseplants; and to examine factors affecting acceptance of control measures. The results showed an average of more than four potential plant-related larval habitats per premises, of which only 0.4% were occupied by the vector. Plant-related containers represented 31% of all the containers with Aedes aegypti larvae. Although a sample of 126 respondents was able to list 105 different houseplant names, 49% of the positive plants were of two types: ferns and the ornamental plant Dieffenbachia avoena. The public's apparent unwillingness to accept recommended anti-aegypti control measures involving houseplants seems related to the relative rarity of aegypti larvae in the very common houseplant containers, the control program's poor credibility as a source of information about plants, and a perception that the recommended control measures are harmful to plants. An intervention currently being planned for dengue control will use educational material that refers specifically to those plants whose containers are most commonly found to harbor aegypti larvae; it will also utilize information sources such as botanists with greater credibility regarding plants; and it will set out alternative plant care recommendations that are more likely to appeal as beneficial to the plants and that will stand a better chance of being accepted. PMID:9149524

  2. Evaluation of dengue virus strains for human challenge studies.

    PubMed

    Mammen, M P; Lyons, A; Innis, B L; Sun, W; McKinney, D; Chung, R C Y; Eckels, K H; Putnak, R; Kanesa-thasan, N; Scherer, J M; Statler, J; Asher, L V; Thomas, S J; Vaughn, D W

    2014-03-14

    Discordance between the measured levels of dengue virus neutralizing antibody and clinical outcomes in the first-ever efficacy study of a dengue tetravalent vaccine (Lancet, Nov 2012) suggests a need to re-evaluate the process of pre-screening dengue vaccine candidates to better predict clinical benefit prior to large-scale vaccine trials. In the absence of a reliable animal model and established correlates of protection for dengue, a human dengue virus challenge model may provide an approach to down-select vaccine candidates based on their ability to reduce risk of illness following dengue virus challenge. We report here the challenge of flavivirus-naïve adults with cell culture-passaged dengue viruses (DENV) in a controlled setting that resulted in uncomplicated dengue fever (DF). This sets the stage for proof-of-concept efficacy studies that allow the evaluation of dengue vaccine candidates in healthy adult volunteers using qualified DENV challenge strains well before they reach field efficacy trials involving children. Fifteen flavivirus-naïve adult volunteers received 1 of 7 DENV challenge strains (n=12) or placebo (n=3). Of the twelve volunteers who received challenge strains, five (two DENV-1 45AZ5 and three DENV-3 CH53489 cl24/28 recipients) developed DF, prospectively defined as ≥2 typical symptoms, ≥48h of sustained fever (>100.4°F) and concurrent viremia. Based on our study and historical data, we conclude that the DENV-1 and DENV-3 strains can be advanced as human challenge strains. Both of the DENV-2 strains and one DENV-4 strain failed to meet the protocol case definition of DF. The other two DENV-4 strains require additional testing as the illness approximated but did not satisfy the case definition of DF. Three volunteers exhibited effusions (1 pleural/ascites, 2 pericardial) and 1 volunteer exhibited features of dengue (rash, lymphadenopathy, neutropenia and thrombocytopenia), though in the absence of fever and symptoms. The occurrence of

  3. Synthesis, activity, and QSAR studies of tryptamine derivatives on third-instar larvae of Aedes aegypti Linn.

    PubMed

    Oliveira, Rafael R B; Brito, Thaysnara B; Nepel, Angelita; Costa, Emmanoel V; Barison, Andersson; Nunes, Rogéria S; Santos, Roseli L C; Cavalcanti, Sócrates C H

    2014-01-01

    Special attention has been given to the mosquito Aedes aegypti Linn. (Diptera: Culicidae) owing to numerous dengue epidemic outbreaks worldwide. Failure to control vector spreading is accounted for unorganized urban growth and resistance to larvicides and insecticides. Therefore, researchers are currently searching for new and more efficient larvicides and insecticides to aid dengue control measures. Triptamine is known to affect insect behavior, development, and physiology. Expression of this compound in plants has reduced the growth rate of herbivore insects. In view of these facts, it was of our interest to synthesize triptamine amide derivatives as potential larvicides against Ae. aegypti, establishing a Structure-Activity Relationship. Eleven amide derivatives of triptamine were synthesized, characterized, and evaluated for their larvicidal activity against third-instar Ae. aegypti larvae. N-(2-(1H-indol-3-yl)ethyl)-2,2,2-trichloroacetamide exhibited the highest overall larvicidal potency, while N-(2-(1H-Indol-3-yl)ethyl) acetamide displayed the lowest larvicidal potency. A regression equation correlating the larvicidal activity with Log P was obtained. We have found a clear relationship between the larvicidal activity of non-chlorinated compounds and Log P. Analysis of the relationship between Log P and larvicidal activity against Ae. aegypti may be useful in the evaluation of potential larvicidal compounds. PMID:24295020

  4. Influence of container design on predation rate of potential biocontrol agent, Toxorhynchites splendens (Diptera: Culicidae) against dengue vector.

    PubMed

    Mohamad, N; Zuharah, W F

    2014-03-01

    Toxorhynchites splendens larvae are a natural predator of dengue vector mosquito larvae, Aedes albopictus. This study was carried out to evaluate the predation rate of Tx. splendens third instar larvae on Ae. albopictus larvae in 24 h. Each predator was offered prey at a density between 10 to 50 individuals. Predation rate of Tx. splendens were also tested with two manipulated factors; various types of container and different water volumes. The experiment was evaluated in man-made containers (tin cans, plastic drinking glasses and rubber tires) and natural container (bamboo stumps) which were filled with different water volumes (full, half full, 1/4 full, and 1/8 full). The prey density and the characteristics of the container were found as significant factors which influence the predation rate of Tx. splendens. The predator consumed significantly more prey at higher prey densities (40 and 50 preys) compared to the lowest density (10 preys) (F=3.935, df=4, p=0.008). The results showed significantly higher consumption in horizontal shaped container of rubber tire than in vertical shape of bamboo stumps (F=3.100, df=3, p=0.029). However, the water volume had no significant effect on predation rate of Tx. splendens (F=1.736, df=3, p=0.162). We generally suggest that Tx. splendens is best to be released in discarded tires or any other containers with horizontal shape design with wide opening since Tx. splendens can become more effective in searching prey in this type of container design. This predator is also a suitable biocontrol candidates to be introduced either in wet and dry seasons in Malaysia. PMID:24862057

  5. EFFECTS OF THERMAL POLLUTION OF PELAGIC LARVAE OF CRUSTACEA

    EPA Science Inventory

    Larvae of six species, Cancer irroratus, C. borealis and Homarus americanus of coastal waters (high salinity), and Palaemonetes pugio, Pagurus longicarpus and Rhithropanopeus harrisii, from the estuarine region (variable salinity) were studied. Larvae were cultured at various com...

  6. Field evaluation of a lethal ovitrap against dengue vectors in Brazil.

    PubMed

    Perich, M J; Kardec, A; Braga, I A; Portal, I F; Burge, R; Zeichner, B C; Brogdon, W A; Wirtz, R A

    2003-06-01

    Field evaluation of a "lethal ovitrap" (LO) to control dengue vector Aedes mosquitoes (Diptera: Culicidae), was undertaken in two Brazilian municipalities, Areia Branca and Nilopolis, in the State of Rio de Janeiro. The LO is designed to kill Aedes via an insecticide-treated ovistrip (impregnated with deltamethrin). In each municipality, the intervention was applied to a group of 30 houses (10 LOs/house) and compared to 30 houses without LOs in the same neighbourhood. Five LOs were put outside and five LOs inside each treated house. Three methods of monitoring Aedes density were employed: (i) percentage of containers positive for larvae and/or pupae; (ii) total pupae/house; (iii) total adult females/house collected by aspirator indoors. Weekly mosquito surveys began during the month before LO placement, by sampling from different groups of 10 houses/week for 3 weeks pre-intervention (i.e. 30 houses/month) and for 3 months post-intervention in both treated and untreated areas. Prior to LO placement at the end of February 2001, Aedes aegypti (L) densities were similar among houses scheduled for LO treatment and comparison (untreated control) at each municipality. Very few Ae. albopictus (Skuse) were found and this species was excluded from the assessment. Post-intervention densities of Ae. aegypti were significantly reduced for most comparators (P < 0.01), as shown by fewer positive containers (4-5 vs. 10-18) and pupae/house (0.3-0.7 vs. 8-10) at LO-treated vs. untreated houses, 3 months post-treatment at both municipalities. Numbers of adult Ae. aegypti females indoors were consistently reduced in LO-treated houses at Areia Branca (3.6 vs. 6.8/house 3 months post-intervention) but not at Niloplis (approximately 3/house, attributed to immigration). These results demonstrate sustained impact of LOs on dengue vector population densities in housing conditions of Brazilian municipalities. PMID:12823838

  7. Undesirable Consequences of Insecticide Resistance following Aedes aegypti Control Activities Due to a Dengue Outbreak

    PubMed Central

    Maciel-de-Freitas, Rafael; Avendanho, Fernando Campos; Santos, Rosangela; Sylvestre, Gabriel; Araújo, Simone Costa; Lima, José Bento Pereira; Martins, Ademir Jesus; Coelho, Giovanini Evelim; Valle, Denise

    2014-01-01

    Background During a dengue outbreak with co-circulation of DENV-1 and -2 in the city of Boa Vista, one patient was diagnosed with DENV-4, a serotype supposed absent from Brazil for almost 30 years. The re-emergence of DENV-4 triggered the intensification of mechanical and chemical Aedes aegypti control activities in order to reduce vector density and avoid DENV-4 dissemination throughout the country. Methods/Principal Findings Vector control activities consisted of (a) source reduction, (b) application of diflubenzuron against larvae and (c) vehicle-mounted space spraying of 2% deltamethrin to eliminate adults. Control activity efficacy was monitored by comparing the infestation levels and the number of eggs collected in ovitraps before and after interventions, performed in 22 Boa Vista districts, covering an area of ∼80% of the city and encompassing 56,837 dwellings. A total of 94,325 containers were eliminated or treated with diflubenzuron. The most frequently positive containers were small miscellaneous receptacles, which corresponded to 59% of all positive breeding sites. Insecticide resistance to deltamethrin was assessed before, during and after interventions by dose-response bioassays adopting WHO-based protocols. The intense use of the pyrethroid increased fourfold the resistance ratio of the local Ae. aegypti population only six months after the beginning of vector control. Curiously, this trend was also observed in the districts in which no deltamethrin was applied by the public health services. On the other hand, changes in the resistance ratio to the organophosphate temephos seemed less influenced by insecticide in Boa Vista. Conclusions Despite the intense effort, mosquito infestation levels were only slightly reduced. Besides, the median number of eggs in ovitraps remained unaltered after control activity intensification. The great and rapid increase in pyrethroid resistance levels of natural Ae. aegypti populations is discussed in the context of

  8. Evaluation of the MRL Diagnostics Dengue Fever Virus IgM Capture ELISA and the PanBio Rapid Immunochromatographic Test for Diagnosis of Dengue Fever in Jamaica

    PubMed Central

    Palmer, Carol J.; King, S. Dorothy; Cuadrado, Raul R.; Perez, Eddy; Baum, Mariana; Ager, Arba L.

    1999-01-01

    We evaluated two new commercial dengue diagnostic tests, the MRL Diagnostics Dengue Fever Virus IgM Capture ELISA and the PanBio Rapid Immunochromatographic Test, on serum samples collected during a dengue epidemic in Jamaica. The MRL ELISA method correctly identified 98% (78 of 80) of the samples as dengue positive, while the PanBio test identified 100% (80 of 80). Both tests were 100% (20 samples of 20) specific. PMID:10203534

  9. Evaluation of the MRL diagnostics dengue fever virus IgM capture ELISA and the PanBio Rapid Immunochromatographic Test for diagnosis of dengue fever in Jamaica.

    PubMed

    Palmer, C J; King, S D; Cuadrado, R R; Perez, E; Baum, M; Ager, A L

    1999-05-01

    We evaluated two new commercial dengue diagnostic tests, the MRL Diagnostics Dengue Fever Virus IgM Capture ELISA and the PanBio Rapid Immunochromatographic Test, on serum samples collected during a dengue epidemic in Jamaica. The MRL ELISA method correctly identified 98% (78 of 80) of the samples as dengue positive, while the PanBio test identified 100% (80 of 80). Both tests were 100% (20 samples of 20) specific. PMID:10203534

  10. Evolution of foraging behavior in Drosophilid larvae

    NASA Astrophysics Data System (ADS)

    Rivera-Alba, Marta; Kabra, Mayank; Branson, Kristin; Mirth, Christen

    2015-03-01

    Drosophilids, like other insects, go through a larval phase before metamorphosing into adults. Larvae increase their body weight by several orders of magnitude in a few days. We therefore hypothesized that foraging behavior is under strong evolutionary pressure to best fit the larval environment. To test our hypothesis we used a multidisciplinary approach to analyze foraging behavior across species and larval stages. First, we recorded several videos of larvae foraging for each of 47 Drosophilid species. Then, using a supervised machine learning approach, we automatically annotated the video collection for the foraging sub-behaviors, including crawling, turning, head casting or burrowing. We also computed over 100 features to describe the posture and dynamics of each animal in each video frame. From these data, we fit models to the behavior of each species. The models each had the same parametric form, but differed in the exact parameters. By simulating larva behavior in virtual arenas we can infer which properties of the environments are better for each species. Comparisons between these inferred environments and the actual environments where these animals live will give us a deeper understanding about the evolution of foraging behavior in Drosophilid larvae.

  11. Developing a Time Series Predictive Model for Dengue in Zhongshan, China Based on Weather and Guangzhou Dengue Surveillance Data

    PubMed Central

    Liu, Kangkang; Xia, Yao; Lu, Yi; Jing, Qinlong; Yang, Zhicong; Hu, Wenbiao; Lu, Jiahai

    2016-01-01

    Background Dengue is a re-emerging infectious disease of humans, rapidly growing from endemic areas to dengue-free regions due to favorable conditions. In recent decades, Guangzhou has again suffered from several big outbreaks of dengue; as have its neighboring cities. This study aims to examine the impact of dengue epidemics in Guangzhou, China, and to develop a predictive model for Zhongshan based on local weather conditions and Guangzhou dengue surveillance information. Methods We obtained weekly dengue case data from 1st January, 2005 to 31st December, 2014 for Guangzhou and Zhongshan city from the Chinese National Disease Surveillance Reporting System. Meteorological data was collected from the Zhongshan Weather Bureau and demographic data was collected from the Zhongshan Statistical Bureau. A negative binomial regression model with a log link function was used to analyze the relationship between weekly dengue cases in Guangzhou and Zhongshan, controlling for meteorological factors. Cross-correlation functions were applied to identify the time lags of the effect of each weather factor on weekly dengue cases. Models were validated using receiver operating characteristic (ROC) curves and k-fold cross-validation. Results Our results showed that weekly dengue cases in Zhongshan were significantly associated with dengue cases in Guangzhou after the treatment of a 5 weeks prior moving average (Relative Risk (RR) = 2.016, 95% Confidence Interval (CI): 1.845–2.203), controlling for weather factors including minimum temperature, relative humidity, and rainfall. ROC curve analysis indicated our forecasting model performed well at different prediction thresholds, with 0.969 area under the receiver operating characteristic curve (AUC) for a threshold of 3 cases per week, 0.957 AUC for a threshold of 2 cases per week, and 0.938 AUC for a threshold of 1 case per week. Models established during k-fold cross-validation also had considerable AUC (average 0.938–0.967). The

  12. The Sublethal Effects of the Entomopathic Fungus Leptolegnia chapmanii on Some Biological Parameters of the Dengue Vector Aedes aegypti

    PubMed Central

    Pelizza, S.A.; Scorsetti, A.C.; Tranchida, M.C.

    2013-01-01

    The mosquito Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of dengue in the Americas. The use of chemical insecticides is recommended during outbreaks of dengue in order to reduce the number of adult mosquitoes; however, because Ae. aegypti is highly synanthropic, the use of insecticides in densely populated areas is a dangerous practice. Leptolegnia chapmanii Seymour (Straminipila: Peronosporomycetes) is an entomopathogenic microorganism that has demonstrated marked pathogenicity toward the larvae of a number of mosquito species, with little or no effect on non-target insects. Therefore, the purpose of this study was to determine the sublethal effects of L. chapmanii on fecundity, number of gonotrophic cycles, fertility, and relationship between wing length and fecundity in Ae. aegypti females. Ae. aegypti females that survived infection with L. chapmanii laid fewer eggs, had a smaller number of gonotrophic cycles, had shorter wings, and were less fertile than controls. This is the first study on the sublethal effects experienced by specimens of Ae. aegypti that survived infection with zoospores of L. chapmanii. Although field studies should be carried out, the results obtained in this study are encouraging because the high and rapid larval mortality caused by L. chapmanii coupled with the reduction of reproductive capacity in Ae. aegypti females seem to cause a significant reduction in the number of adults in the mid and long term, thereby reducing the health risks associated with Ae. aegypti. PMID:23901823

  13. Replicate surveys of larval habitats of Aedes aegypti in relation to dengue haemorrhagic fever in Bangkok, Thailand*

    PubMed Central

    Tonn, R. J.; Sheppard, P. M.; MacDonald, W. W.; Bang, Y. H.

    1969-01-01

    Dengue haemorrhagic fever in Bangkok and Thonburi occurs principally during the wet season. The mosquito vector is Aedes aegypti. A study was made of the larval habitats of A. aegypti in 14 localities, at three different times of the year, to determine whether there were fluctuations in the A. aegypti population, as measured by the number of occupied habitats, which could be correlated with the incidence of the infection. The habitats were classified into 6 categories and a single larva was collected for identification from each one that was occupied. The number and percentage of occupied habitats of each category per 100 houses were analysed to determine whether there were differences between localities and between times of the year. Almost all the comparisons between localities were highly significant. There was evidence of slight changes in the number of occupied habitats from time to time, the chief increase being between the cool and the warm seasons and the chief decrease from the wet to the cool season, but it seems unlikely that outbreaks of dengue haemorrhagic fever can be explained by increases in A. aegypti densities during the wet season. PMID:5307596

  14. Exposure of a Dengue Vector to Tea and Its Waste: Survival, Developmental Consequences, and Significance for Pest Management.

    PubMed

    Dieng, Hamady; Tan Yusop, Nur Syafiqah Bt; Kamal, Nurafidah Natasyah Bt; Ahmad, Abu Hassan; Ghani, Idris Abd; Abang, Fatimah; Satho, Tomomitsu; Ahmad, Hamdan; Zuharah, Wan Fatma; Majid, Abdul Hafiz Ab; Morales, Ronald E; Morales, Noppawan P; Hipolito, Cirilo N; Noweg, Gabriel Tonga

    2016-05-11

    Dengue mosquitoes are evolving into a broader global public health menace, with relentless outbreaks and the rise in number of Zika virus disease cases as reminders of the continued hazard associated with Aedes vectors. The use of chemical insecticides-the principal strategy against mosquito vectors-has been greatly impeded due to the development of insecticide resistance and the shrinking spectrum of effective agents. Therefore, there is a pressing need for new chemistries for vector control. Tea contains hundreds of chemicals, and its waste, which has become a growing global environmental problem, is almost as rich in toxicants as green leaves. This paper presents the toxic and sublethal effects of different crude extracts of tea on Aedes albopictus. The survival rates of larvae exposed to tea extracts, especially fresh tea extract (FTE), were markedly lower than those in the control treatment group. In addition to this immediate toxicity against different developmental stages, the extracts tested caused a broad range of sublethal effects. The developmental time was clearly longer in containers with tea, especially in those with young larvae (YL) and FTE. Among the survivors, pupation success was reduced in containers with tea, which also produced low adult emergence rates with increasing tea concentration. The production of eggs tended to be reduced in females derived from the tea treatment groups. These indirect effects of tea extracts on Ae. albopictus exhibited different patterns according to the exposed larval stage. Taken together, these findings indicate that tea and its waste affect most key components of Ae. albopictus vectorial capacity and may be useful for dengue control. Reusing tea waste in vector control could also be a practical solution to the problems associated with its pollution. PMID:27115536

  15. Neural network diagnostic system for dengue patients risk classification.

    PubMed

    Faisal, Tarig; Taib, Mohd Nasir; Ibrahim, Fatimah

    2012-04-01

    With the dramatic increase of the worldwide threat of dengue disease, it has been very crucial to correctly diagnose the dengue patients in order to decrease the disease severity. However, it has been a great challenge for the physicians to identify the level of risk in dengue patients due to overlapping of the medical classification criteria. Therefore, this study aims to construct a noninvasive diagnostic system to assist the physicians for classifying the risk in dengue patients. Systematic producers have been followed to develop the system. Firstly, the assessment of the significant predictors associated with the level of risk in dengue patients was carried out utilizing the statistical analyses technique. Secondly, Multilayer perceptron neural network models trained via Levenberg-Marquardt and Scaled Conjugate Gradient algorithms was employed for constructing the diagnostic system. Finally, precise tuning for the models' parameters was conducted in order to achieve the optimal performance. As a result, 9 noninvasive predictors were found to be significantly associated with the level of risk in dengue patients. By employing those predictors, 75% prediction accuracy has been achieved for classifying the risk in dengue patients using Scaled Conjugate Gradient algorithm while 70.7% prediction accuracy were achieved by using Levenberg-Marquardt algorithm. PMID:20703665

  16. Seroprevalence of asymptomatic dengue infection in children in Lahore.

    PubMed

    Mohsin, S N; Ghafoor, F; Saleem, M; Ghous, R; Aasim, M

    2016-08-01

    Dengue has become a global problem in past few decades, with half of the world's population at risk of infection. For some countries of Asia and Latin America, severe dengue is a major cause of serious illness and even death in children. Pakistan has been reported as a hyperendemic area for dengue infection. Our study aimed to find seroprevalence of past dengue infection in asymptomatic children of Lahore with no previous history of dengue infection. A total of 400 samples were collected from children aged 1-12 years in Lahore using random sampling. The inclusion criteria were children aged 1-12 years, who had no previous symptoms of dengue fever during their lives. Children with known immunodeficiency status or fever at the time of recruitment were excluded from the study. Commercially available ELISA kits were used to determine the IgG status in sera of children. The data obtained was entered and analysed using SPSS v. 20.0. The overall prevalence of asymptomatic dengue infection was found to be 25%. There was no statistically significant difference between prevalence of infection in male and female children. There was, however, a strong relationship between increasing age of the child and number of cases with infection, with low incidence in children aged ⩽5 years. PMID:27019361

  17. Viraemia in patients with naturally acquired dengue infection*

    PubMed Central

    Gubler, D. J.; Suharyono, W.; Tan, R.; Abidin, M.; Sie, A.

    1981-01-01

    The magnitude and duration of dengue viraemia were studied in 153 patients with naturally acquired dengue infection in Jakarta, Indonesia. The duration of viraemia ranged from 2 to 12 days, but most patients had detectable circulating virus for 4-5 days. Accurate measurement of peak virus titres was not possible for many patients because of late admission to the hospital. Composite pictures of viraemia for each serotype, however, showed that many patients infected with dengue 1, 2, or 3 had circulating virus titres ranging from barely detectable to over 108 MID50 per ml for 3-5 days. Virus titres in patients infected with dengue 4 were about 100-fold lower. Dengue haemagglutination-inhibition antibody titres of 80 or less had little effect on viraemia, but antibody titres of 160 or greater were associated with a decrease in virus isolation rate and in virus titre. The duration and magnitude of viraemia did not vary significantly with the severity of the disease and was only slightly higher in patients classified as primary dengue infections than in those classified as secondary infections. Measurement of viraemia in fatal dengue haemorrhagic fever (DHF) cases showed that these patients had significant quantities of circulating virus at the time of death. PMID:6976230

  18. Evaluation of aminotransferase abnormality in dengue patients: A meta analysis.

    PubMed

    Wang, Xiao-Jun; Wei, Hai-Xia; Jiang, Shi-Chen; He, Cheng; Xu, Xiu-Juan; Peng, Hong-Juan

    2016-04-01

    Dengue virus is a type of flavivirus transmitted by Aedes mosquitoes. The symptoms of infection by this virus range from asymptomatic or mild symptomatic dengue fever (DF) to dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS). Significant abnormality in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) has been shown in a large number of dengue infection cases and to be indicator for liver injury provided that there are no other combined infections or liver injury. This study aims to assess the abnormal levels of liver aminotransferase in dengue patients. The related literature was searched in multiple databases, including PubMed, Embase, Google Scholar and Cochrane Library. The literature was selected through strict inclusion and exclusion criteria, and the quantitative synthesis of the liver aminotransferase abnormality was performed with R software. The fixed or random effects model was employed based on the results of the statistical test for homogeneity. In total, 15 studies were included. The proportion of AST abnormality with 95% confidence interval (95% CI) was 0.80 (95% CI: 0.56-0.92) in DHF patients and 0.75 (95% CI: 0.63-0.84) in DF patients; the proportion of ALT abnormality was 0.54 (95% CI: 0.34-0.73) in DHF patients and 0.52 (95% CI: 0.41-0.63) in DF patients. Serum ALT and AST levels may be indicators for evaluating liver injury in dengue infection and for diagnosis and treatment effect. PMID:26739659

  19. Heart and Skeletal Muscle Are Targets of Dengue Virus Infection

    PubMed Central

    Salgado, Doris Martha; Eltit, José Miguel; Mansfield, Keith; Panqueba, César; Castro, Dolly; Vega, Martha Rocio; Xhaja, Kris; Schmidt, Diane; Martin, Katherine J.; Allen, Paul D.; Rodriguez, Jairo Antonio; Dinsmore, Jonathan H.; López, José Rafael; Bosch, Irene

    2010-01-01

    Background Dengue fever is one of the most significant re-emerging tropical diseases, despite our expanding knowledge of the disease, viral tropism is still not known to target heart tissues or muscle. Methods A prospective pediatric clinical cohort of 102 dengue hemorrhagic fever patients from Colombia, South America, was followed for 1 year. Clinical diagnosis of myocarditis was routinely performed. Electrocardiograph and echocardiograph analysis were performed to confirm those cases. Immunohistochemistry for detection of dengue virus and inflammatory markers was performed on autopsied heart tissue. In vitro studies of human striated skeletal fibers (myotubes) infected with dengue virus were used as a model for myocyte infection. Measurements of intracellular Ca2+ concentration as well as immunodetection of dengue virus and inflammation markers in infected myotubes were performed. Results Eleven children with dengue hemorrhagic fever presented with symptoms of myocarditis. Widespread viral infection of the heart, myocardial endothelium, and cardiomyocytes, accompanied by inflammation was observed in 1 fatal case. Immunofluorescence confocal microscopy showed that myotubes were infected by dengue virus and had increased expression of the inflammatory genes and protein IP-10. The infected myotubes also had increases in intracellular Ca2+ concentration. Conclusions Vigorous infection of heart tissues in vivo and striated skeletal cells in vitro are demonstrated. Derangements of Ca2+ storage in the infected cells may directly contribute to the presentation of myocarditis in pediatric patients. PMID:20032806

  20. Dengue fever in travellers: A challenge for European physicians.

    PubMed

    Bulugahapitiya, Uditha; Siyambalapitiya, Sajith; Seneviratne, Suranjith L; Fernando, Devaka J S

    2007-05-01

    Dengue fever (DF) is one of the world's emerging infectious diseases. The steady increase in European tourists, as well as soldiers serving on peacekeeping duties, in endemic areas, coupled with the present resurgence of dengue, raises the risk of exposure for a large number of European travellers. Significant numbers of travellers have, in fact, developed DF. There is a risk of dengue haemorrhagic fever (DHF) in travellers who revisit the same place, and they have the potential not only to acquire, but also to spread, the dengue viral infection. Of concern is the potential for a dengue outbreak in a previously dengue-free country through imported cases. Another major concern is the potential area of dengue transmission, due to spread of its vectors through sizeable parts of southern Europe. In addition to the risk of haemorrhagic fever in returning tourists, the introduction of DF by returning travellers, whether they have symptoms or are unaffected by signs and symptoms of the disease, poses a threat to health systems in Europe. PMID:17449389

  1. Inhibitory effect of doxycycline against dengue virus replication in vitro.

    PubMed

    Rothan, Hussin A; Mohamed, Zulqarnain; Paydar, Mohammadjavad; Rahman, Noorsaadah Abd; Yusof, Rohana

    2014-04-01

    Doxycycline is an antibiotic derived from tetracycline that possesses antimicrobial and anti-inflammatory activities. Antiviral activity of doxycycline against dengue virus has been reported previously; however, its anti-dengue properties need further investigation. This study was conducted to determine the potential activity of doxycycline against dengue virus replication in vitro. Doxycycline inhibited the dengue virus serine protease (DENV2 NS2B-NS3pro) with an IC50 value of 52.3 ± 6.2 μM at 37 °C (normal human temperature) and 26.7 ± 5.3 μM at 40 °C (high fever temperature). The antiviral activity of doxycycline was first tested at different concentrations against DENV2 using a plaque-formation assay. The virus titter decreased significantly after applying doxycycline at levels lower than its 50 % cytotoxic concentration (CC50, 100 μM), showing concentration-dependent inhibition with a 50 % effective concentration (EC50) of approximately 50 μM. Doxycycline significantly inhibited viral entry and post-infection replication of the four dengue serotypes, with serotype-specific inhibition (high activity against DENV2 and DENV4 compared to DENV1 and DENV3). Collectively, these findings underline the need for further experimental and clinical studies on doxycycline, utilizing its anti-dengue and anti-inflammatory activities to attenuate the clinical symptoms of dengue virus infection. PMID:24142271

  2. Potential anti-dengue medicinal plants: a review.

    PubMed

    Abd Kadir, Siti Latifah; Yaakob, Harisun; Mohamed Zulkifli, Razauden

    2013-10-01

    Dengue fever causes mortality and morbidity around the world, specifically in the Tropics and subtropic regions, which has been of major concern to governments and the World Health Organization (WHO). As a consequence, the search for new anti-dengue agents from medicinal plants has assumed more urgency than in the past. Medicinal plants have been used widely to treat a variety of vector ailments such as malaria. The demand for plant-based medicines is growing as they are generally considered to be safer, non-toxic and less harmful than synthetic drugs. This article reviews potential anti-dengue activities from plants distributed around the world. Sixty-nine studies from 1997 to 2012 describe 31 different species from 24 families that are known for their anti-dengue activities. About ten phytochemicals have been isolated from 11 species, among which are compounds with the potential for development of dengue treatment. Crude extracts and essential oils obtained from 31 species showed a broad activity against Flavivirus. Current studies show that natural products represent a rich potential source of new anti-dengue compounds. Further ethnobotanical surveys and laboratory investigations are needed established the potential of identified species in contributing to dengue control. PMID:23591999

  3. Pathogenesis of Dengue: Dawn of a New Era

    PubMed Central

    Halstead, Scott B.

    2015-01-01

    Dengue virus (DENV) infections of humans were long thought to be self-limited and of low mortality. Beginning in the 1950s, at the time when four different DENVs were discovered, a lethal variant of dengue emerged. Dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) initially observed in Southeast Asia now has spread throughout the world. Two risk factors for DHF/DSS are well-established: severe disease occurs during a second heterotypic DENV infection or during a first DENV infection in infants born to dengue-immune mothers. A large number of hypotheses have been proposed to explain severe dengue disease. As discussed, few of them attempt to explain why severe disease occurs under the two different immunological settings. New experimental evidence has demonstrated that DENV non-structural protein 1 (NS1) is toll-receptor 4 agonist that stimulates primary human myeloid cells to produce the same cytokines observed during the course of severe dengue disease. In addition, NS1 directly damages endothelial cells. These observations have been repeated and extended to an in vivo mouse model. The well-established phenomenon, antibody-dependent enhancement of DENV infection in Fc-receptor-bearing cells, should similarly enhance the production of DENV NS1 in humans, providing a unitary mechanism for severe disease in both immunological settings PMID:26918141

  4. Impact of larviciding with a Bacillus thuringiensis israelensis formulation, VectoBac WG, on dengue mosquito vectors in a dengue endemic site in Selangor State, Malaysia.

    PubMed

    Lee, H L; Chen, C D; Masri, S Mohd; Chiang, Y F; Chooi, K H; Benjamin, S

    2008-07-01

    The field bioefficacy of a wettable granule (WG) formulation of Bacillus thuringiensis israelensis (Bti), VectoBac WG (Bti strain AM65-52) against dengue vectors, Aedes aegypti and Ae albopictus; was evaluated in a suburban residential area (TST) and in a temporary settlement site (KB) in the state of Selangor, Malaysia. Pre-control ovitrap surveillance of the trial sites indicated a high population of both types of Aedes mosquitoes. The populations were monitored continuously by weekly ovitrapping. Bti was sprayed biweekly at a dosage of 500 g/ha by using a mist-blower. The spray application was targeted into outdoor larval habitats. If required, Bti formulation was also applied directly into indoor water-holding containers at 8 g/1,000 l. Based on ovitrap surveillance, a significant reduction in Aedes populations was evident 4 weeks after initiating the first Bti treatment. The ovitrap index (OI) and the larvae density decreased drastically in both trial sites. In TST, the indoor OI was significantly reduced from 57.50 +/- 7.50% to 19.13 +/- 5.49% (p<0.05), while the outdoor OI decreased from 38.89 +/- 11.11% to 15.36 +/- 5.93%. In KB, similarly, the OI was significantly reduced by more than half, from 66.66 +/- 6.67% to 30.26 +/- 2.99% (p< 0.05). In all cases, the reduction in OI was paralleled by reduction in larval density. PMID:19058596

  5. Antibodies from dengue patient sera cross-react with endothelial cells and induce damage.

    PubMed

    Lin, Chiou-Feng; Lei, Huan-Yao; Shiau, Ai-Li; Liu, Ching-Chuan; Liu, Hsiao-Sheng; Yeh, Trai-Ming; Chen, Shun-Hua; Lin, Yee-Shin

    2003-01-01

    Dengue virus infection causes a wide range of diseases from the mild febrile illness dengue fever to the life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Vascular leakage and hemorrhagic syndrome are the clinical features associated with dengue infection, yet the mechanisms remain unclear. In this study, the cross-reactivity of dengue patient sera with endothelial cells was demonstrated. There were higher percentages of endothelial cells reactive with dengue hemorrhagic fever/dengue shock syndrome patient sera than those with dengue fever patient sera. The percentages of endothelial cells reactive with patient serum IgM were higher than those with IgG. Further studies showed that the endothelial cell binding activity was inhibited by pretreatment with dengue virus nonstructural protein 1 (NS1). The antibodies against NS1 produced after dengue virus infection may, at least in part, account for the cross-reactivity of patient sera with endothelial cells. Furthermore, dengue patient sera induced endothelial cell apoptosis via a caspase-dependent pathway that was also inhibited by NS1 pretreatment. In addition to apoptosis, patient sera caused cell lysis in the presence of complement, and DHF/DSS patient sera showed higher percentages of cytotoxicity than dengue fever patient sera. Thus, the generation of cross-reactive autoantibodies against endothelial cells would lead to their dysfunction, which may play a role in the pathogenesis of dengue virus infection. PMID:12436482

  6. Dengue hemorrhagic fever and the kidney.

    PubMed

    Vachvanichsanong, Prayong; Thisyakorn, Usa; Thisyakorn, Chule

    2016-04-01

    Dengue virus infection (DVI)/dengue hemorrhagic fever (DHF) is a common febrile illness with a variety of severities. The mortality rate is high in dengue shock syndrome (DSS), caused by circulatory failure due to plasma leakage resulting in multi-organ failure. However, acute kidney injury (AKI) is rarely reported. In areas of endemic DVI, the prevalence of AKI due to DVI has been reported to be as high as 6.0 % in children with AKI, and 0.9 % in children with DVI who were admitted to a hospital. The mechanism of AKI in DVI is not clear. It may result from (a) direct injury as in other infectious diseases, (b) an indirect mechanism such as via the immune system, since DHF is an immunological disease, or (c) hypotensive DSS, leading in turn to reduced renal blood supply and renal failure. The mortality rates of DF/DHF, DSS and DHF/DSS-related AKI are <1 %, 12-44 %, and >60 %, respectively. Kidney involvement is not actually that rare, but is under-recognized and often only reported when microscopic hematuria, proteinuria, electrolyte imbalance, or even AKI is found. The prevalence of proteinuria and hematuria has been reported as high as 70-80 % in DVI. A correct diagnosis depends on basic investigations of kidney function such as urinalysis, serum creatinine and electrolytes. Although DVI-related renal involvement is treated supportively, it is still important to make an early diagnosis to prevent AKI and its complications, and if AKI does occur, dialysis may be required. Fortunately, in patients who recover, kidney function usually completely recovers as well. PMID:26699788

  7. Challenges for the formulation of a universal vaccine against dengue.

    PubMed

    Chokephaibulkit, Kulkanya; Perng, Guey Chuen

    2013-05-01

    Dengue is rapidly becoming a disease of an escalating global public health concern. The disease is a vector-borne disease, transmitted by the bite of an Aedes spp. mosquito. Dynamic clinical manifestations, ranging from asymptomatic, flu-like febrile illness, dengue fever (DF) to dengue hemorrhagic fever (DHF) with or without dengue shock syndrome (DSS), make the disease one of the most challenging to diagnose and treat. DF is a self-limited illness, while DHF/DSS, characterized by plasma leakage resulting from an increased vascular permeability, can have severe consequences, including death. The pathogenesis of dengue virus infection remains poorly understood, mainly due to the lack of a suitable animal model that can recapitulate the cardinal features of human dengue diseases. Currently, there is no specific treatment or antiviral therapy available for dengue virus infection and supportive care with vigilant monitoring is the principle course of treatment. Since vector control programs have been largely unsuccessful in preventing outbreaks, vaccination seems to be the most viable option for prevention. There are four dengue viral serotypes and each one of them is capable of causing severe dengue. Although immunity induced by infection by one serotype is effective in protection against the homologous viral serotype, it only has a transient protective effect against infection with the other three serotypes. The meager cross protective immunity generated wanes over time and may even induce a harmful effect at the time of subsequent secondary infection. Thus, it is imperative to have a vaccine that can elicit equal and long-lasting immunity to all four serotypes simultaneously. Numerous tetravalent vaccines are currently either in the pipeline for clinical trials or under development. For those frontrunner tetravalent vaccines in clinical trials, despite good safety and immunogenicity profiles registered, issues such as imbalanced immune responses between serotypes

  8. Forecast of Dengue Incidence Using Temperature and Rainfall

    PubMed Central

    Hii, Yien Ling; Zhu, Huaiping; Ng, Nawi; Ng, Lee Ching; Rocklöv, Joacim

    2012-01-01

    Introduction An accurate early warning system to predict impending epidemics enhances the effectiveness of preventive measures against dengue fever. The aim of this study was to develop and validate a forecasting model that could predict dengue cases and provide timely early warning in Singapore. Methodology and Principal Findings We developed a time series Poisson multivariate regression model using weekly mean temperature and cumulative rainfall over the period 2000–2010. Weather data were modeled using piecewise linear spline functions. We analyzed various lag times between dengue and weather variables to identify the optimal dengue forecasting period. Autoregression, seasonality and trend were considered in the model. We validated the model by forecasting dengue cases for week 1 of 2011 up to week 16 of 2012 using weather data alone. Model selection and validation were based on Akaike's Information Criterion, standardized Root Mean Square Error, and residuals diagnoses. A Receiver Operating Characteristics curve was used to analyze the sensitivity of the forecast of epidemics. The optimal period for dengue forecast was 16 weeks. Our model forecasted correctly with errors of 0.3 and 0.32 of the standard deviation of reported cases during the model training and validation periods, respectively. It was sensitive enough to distinguish between outbreak and non-outbreak to a 96% (CI = 93–98%) in 2004–2010 and 98% (CI = 95%–100%) in 2011. The model predicted the outbreak in 2011 accurately with less than 3% possibility of false alarm. Significance We have developed a weather-based dengue forecasting model that allows warning 16 weeks in advance of dengue epidemics with high sensitivity and specificity. We demonstrate that models using temperature and rainfall could be simple, precise, and low cost tools for dengue forecasting which could be used to enhance decision making on the timing, scale of vector control operations, and utilization of limited

  9. An Introduction to the Identification of Chironomid Larvae.

    ERIC Educational Resources Information Center

    Mason, William T., Jr.

    This publication is an introductory guide to the identification of Chironomid (Midge) larvae. The larvae of these small flies are an important link in the food chain between algae and microinvertebrates. As a family, the larvae exhibit a wide range of tolerance to environmental factors such as amounts and types of pollutants. Much of this…

  10. Workbook on the Identification of Anopheles Larvae. Preliminary Issue.

    ERIC Educational Resources Information Center

    Pratt, Harry D.; Stojanovich, Chester J.

    This self-instructional booklet is designed to enable malarial control workers to identify the larvae of "Anopheles" species that are important malaria vectors. The morphological features of the larvae are illustrated in a programed booklet, which also contains an illustrated taxonomic key to 25 species of anopheline larvae. A glossary and a short…

  11. Rapid biosynthesis of silver nanoparticles using Crotalaria verrucosa leaves against the dengue vector Aedes aegypti: what happens around? An analysis of dragonfly predatory behaviour after exposure at ultra-low doses.

    PubMed

    Murugan, Kadarkarai; Sanoopa, C P; Madhiyazhagan, Pari; Dinesh, Devakumar; Subramaniam, Jayapal; Panneerselvam, Chellasamy; Roni, Mathath; Suresh, Udaiyan; Nicoletti, Marcello; Alarfaj, Abdullah A; Munusamy, Murugan A; Higuchi, Akon; Kumar, Suresh; Perumalsamy, Haribalan; Ahn, Young-Joon; Benelli, Giovanni

    2016-01-01

    Aedes aegypti is a primary vector of dengue, a mosquito-borne viral disease infecting 50-100 million people every year. Here, we biosynthesised mosquitocidal silver nanoparticles (AgNP) using the aqueous leaf extract of Crotalaria verrucosa. The green synthesis of AgNP was studied by UV-vis spectroscopy, SEM, EDX and FTIR. C. verrucosa-synthesised AgNPs were toxic against A. aegypti larvae and pupae. LC50 of AgNP ranged from 3.496 ppm (I instar larvae) to 17.700 ppm (pupae). Furthermore, we evaluated the predatory efficiency of dragonfly nymphs, Brachydiplax sobrina, against II and III instar larvae of A. aegypti in an aquatic environment contaminated with ultra-low doses of AgNP. Under standard laboratory conditions, predation after 24 h was 87.5% (II) and 54.7% (III). In an AgNP-contaminated environment, predation was 91 and 75.5%, respectively. Overall, C. verrucosa-synthesised AgNP could be employed at ultra-low doses to reduce larval population of dengue vectors enhancing predation rates of dragonfly nymphs. PMID:26284510

  12. Dengue Fever Presenting Atypically with Viral Conjunctivitis and Subacute Thyroiditis.

    PubMed

    Sheraz, Faizan; Tahir, Hassan; Saqi, Jannavi; Daruwalla, Vistasp

    2016-06-01

    The majority of dengue viral infections are asymptomatic, though symptoms may range from self-limiting febrile illness to life threatening hemorrhagic manifestations. As the burden of disease is dramatically rising in recent years, more patients with atypical presentations and rare complications are increasingly reported. Dengue virus may rarely involve different organ systems including CNS, liver, and heart. However, involvement of eye and thyroid is extremely rare. We present a case of 32-year old patient who presented with conjunctivitis and subacute thyroiditis and was found to have dengue viral infection as the cause of these conditions. PMID:27376214

  13. Dengue vaccine: hypotheses to understand CYD-TDV-induced protection.

    PubMed

    Guy, Bruno; Jackson, Nicholas

    2016-01-01

    Dengue virus (DENV) is a human pathogen with a large impact on public health. Although no vaccine against DENV is currently licensed, a recombinant vaccine - chimeric yellow fever virus-DENV tetravalent dengue vaccine (CYD-TDV) - has shown efficacy against symptomatic dengue disease in two recent Phase III clinical trials. Safety observations were also recently reported for these trials. In this Opinion article, we review the data from recent vaccine clinical trials and discuss the putative mechanisms behind the observed efficacy of the vaccine against different forms of the disease, focusing on the interactions between the infecting virus, pre-existing host immunity and vaccine-induced immune responses. PMID:26639777

  14. Economic Impact of Dengue: Multicenter Study across Four Brazilian Regions

    PubMed Central

    Martelli, Celina Maria Turchi; Siqueira, Joao Bosco; Parente, Mirian Perpetua Palha Dias; Zara, Ana Laura de Sene Amancio; Oliveira, Consuelo Silva; Braga, Cynthia; Pimenta, Fabiano Geraldo; Cortes, Fanny; Lopez, Juan Guillermo; Bahia, Luciana Ribeiro; Mendes, Marcia Costa Ooteman; da Rosa, Michelle Quarti Machado; de Siqueira Filha, Noemia Teixeira; Constenla, Dagna; de Souza, Wayner Vieira

    2015-01-01

    Background Dengue is an increasing public health concern in Brazil. There is a need for an updated evaluation of the economic impact of dengue within the country. We undertook this multicenter study to evaluate the economic burden of dengue in Brazil. Methods We estimated the economic burden of dengue in Brazil for the years 2009 to 2013 and for the epidemic season of August 2012- September 2013. We conducted a multicenter cohort study across four endemic regions: Midwest, Goiania; Southeast, Belo Horizonte and Rio de Janeiro; Northeast: Teresina and Recife; and the North, Belem. Ambulatory or hospitalized cases with suspected or laboratory-confirmed dengue treated in both the private and public sectors were recruited. Interviews were scheduled for the convalescent period to ascertain characteristics of the dengue episode, date of first symptoms/signs and recovery, use of medical services, work/school absence, household spending (out-of-pocket expense) and income lost using a questionnaire developed for a previous cost study. We also extracted data from the patients’ medical records for hospitalized cases. Overall costs per case and cumulative costs were calculated from the public payer and societal perspectives. National cost estimations took into account cases reported in the official notification system (SINAN) with adjustment for underreporting of cases. We applied a probabilistic sensitivity analysis using Monte Carlo simulations with 90% certainty levels (CL). Results We screened 2,223 cases, of which 2,035 (91.5%) symptomatic dengue cases were included in our study. The estimated cost for dengue for the epidemic season (2012–2013) in the societal perspective was US$ 468 million (90% CL: 349–590) or US$ 1,212 million (90% CL: 904–1,526) after adjusting for under-reporting. Considering the time series of dengue (2009–2013) the estimated cost of dengue varied from US$ 371 million (2009) to US$ 1,228 million (2013). Conclusions The economic burden

  15. Dengue infection associated hemophagocytic syndrome: Therapeutic interventions and outcome.

    PubMed

    Wan Jamaludin, Wan Fariza; Periyasamy, Petrick; Wan Mat, Wan Rahiza; Abdul Wahid, S Fadilah

    2015-08-01

    Infection associated hemophagocytic syndrome is increasingly recognized as a potentially fatal complication of dengue fever. It should be suspected with prolonged fever beyond seven days associated with hepatosplenomegaly, hyperferritinemia, worsening cytopenias and development of multiorgan dysfunction. Surge of similar pro-inflammatory cytokines observed in dengue associated hemophagocytic syndrome and multiorgan dysfunction may indicate they are part of related inflammatory spectrum. A proportion of patients recovered with supportive therapy, however most required interventions with corticosteroids, intravenous immunoglobulin or chemotherapy. We report three cases of dengue associated IAHS with good outcome following early recognition and treatment with dexamethasone and intravenous immunoglobulin. PMID:26209387

  16. Sculpting the Immunological Response to Dengue Fever by Polytopic Vaccination

    PubMed Central

    Zhou, Hao; Deem, Michael W.

    2015-01-01

    The twin challenges of immunodominance and heterologous immunity have hampered discovery of an effective vaccine against all four dengue viruses. Here we explore how the T cell competition and selection underlying these asymmetrical properties impede effective T cell vaccine design. The theory we develop predicts dengue vaccine clinical trial data well. From the insights that we gain by this theory, we propose two new ideas for design of epitope-based T cell vaccines against dengue: polytopic injection and subdominant epitope priming. PMID:16417956

  17. Complete Genome Sequence of Paenibacillus larvae MEX14, Isolated from Honey Bee Larvae from the Xochimilco Quarter in Mexico City.

    PubMed

    Peréz de la Rosa, D; Pérez de la Rosa, J J; Cossio-Bayugar, R; Miranda-Miranda, E; Lozano, L; Bravo-Díaz, M A; Rocha-Martínez, M K; Sachman-Ruiz, B

    2015-01-01

    Paenibacillus larvae strain MEX14 is a facultative anaerobic endospore-forming bacterium that infects Apis mellifera larvae. Strain MEX14 was isolated from domestic bee larvae collected in a backyard in Mexico City. The estimated genome size was determined to be 4.18 Mb, and it harbors 4,806 protein coding genes (CDSs). PMID:26316636

  18. Complete Genome Sequence of Paenibacillus larvae MEX14, Isolated from Honey Bee Larvae from the Xochimilco Quarter in Mexico City

    PubMed Central

    Peréz de la Rosa, D.; Pérez de la Rosa, J. J.; Cossio-Bayugar, R.; Miranda-Miranda, E.; Lozano, L.; Bravo-Díaz, M. A.; Rocha-Martínez, M. K.

    2015-01-01

    Paenibacillus larvae strain MEX14 is a facultative anaerobic endospore-forming bacterium that infects Apis mellifera larvae. Strain MEX14 was isolated from domestic bee larvae collected in a backyard in Mexico City. The estimated genome size was determined to be 4.18 Mb, and it harbors 4,806 protein coding genes (CDSs). PMID:26316636

  19. Relative Contribution of Dengue IgG Antibodies Acquired during Gestation or Breastfeeding in Mediating Dengue Disease Enhancement and Protection in Type I Interferon Receptor-Deficient Mice

    PubMed Central

    Lee, Pei Xuan; Ong, Li Ching; Libau, Eshele Anak; Alonso, Sylvie

    2016-01-01

    Dengue virus (DENV) causes a spectrum of diseases ranging from self-limiting dengue fever to severe conditions such as haemorrhagic fever and dengue shock syndrome. Antibody-dependent enhancement (ADE) is thought to explain the occurrence of severe dengue whereby pre-existing binding but non-neutralising antibodies enhance DENV infection. The ADE phenomenon is supported by epidemiological findings that infants that born to dengue immune mothers are at greater risk to develop severe dengue upon primary infection. The role of maternally acquired dengue-specific antibodies in disease enhancement was recently recapitulated in a mouse model where mice born to DENV1-immune mothers experienced enhanced disease severity upon DENV2 infection. Here, this study investigates the relative contribution of maternal dengue-specific antibodies acquired during gestation and breastfeeding in dengue disease. Using a surrogate breastfeeding mother experimental approach, we showed that majority of the maternal dengue-specific antibodies were acquired during breastfeeding and conferred an extended enhancement window. On the other hand, in the context of homologous infection, breastfeeding conferred protection. Furthermore, measurement of dengue-specific antibody titres over time in mice born to dengue immune mothers revealed a biphasic pattern of antibody decay as reported in humans. Our work provides evidence of the potential contribution of breast milk-acquired dengue-specific IgG antibodies in enhancement and protection against dengue. Should such contribution be established in humans as well, it may have important implications for the development of guidelines to dengue-immune breastfeeding mothers. PMID:27341339

  20. Relative Contribution of Dengue IgG Antibodies Acquired during Gestation or Breastfeeding in Mediating Dengue Disease Enhancement and Protection in Type I Interferon Receptor-Deficient Mice.

    PubMed

    Lee, Pei Xuan; Ong, Li Ching; Libau, Eshele Anak; Alonso, Sylvie

    2016-06-01

    Dengue virus (DENV) causes a spectrum of diseases ranging from self-limiting dengue fever to severe conditions such as haemorrhagic fever and dengue shock syndrome. Antibody-dependent enhancement (ADE) is thought to explain the occurrence of severe dengue whereby pre-existing binding but non-neutralising antibodies enhance DENV infection. The ADE phenomenon is supported by epidemiological findings that infants that born to dengue immune mothers are at greater risk to develop severe dengue upon primary infection. The role of maternally acquired dengue-specific antibodies in disease enhancement was recently recapitulated in a mouse model where mice born to DENV1-immune mothers experienced enhanced disease severity upon DENV2 infection. Here, this study investigates the relative contribution of maternal dengue-specific antibodies acquired during gestation and breastfeeding in dengue disease. Using a surrogate breastfeeding mother experimental approach, we showed that majority of the maternal dengue-specific antibodies were acquired during breastfeeding and conferred an extended enhancement window. On the other hand, in the context of homologous infection, breastfeeding conferred protection. Furthermore, measurement of dengue-specific antibody titres over time in mice born to dengue immune mothers revealed a biphasic pattern of antibody decay as reported in humans. Our work provides evidence of the potential contribution of breast milk-acquired dengue-specific IgG antibodies in enhancement and protection against dengue. Should such contribution be established in humans as well, it may have important implications for the development of guidelines to dengue-immune breastfeeding mothers. PMID:27341339

  1. Larva of Palaemnema brasiliensis Machado (Odonata: Platystictidae), from Amazonas, Brazil.

    PubMed

    Neiss, Ulisses Gaspar; Hamada, Neusa

    2016-01-01

    The larva of Palaemnema brasiliensis Machado, 2009 is described and illustrated based on last-instar larvae and exuviae of reared larvae collected in a blackwater stream in Barcelos and Presidente Figueiredo municipalities, Amazonas state, Brazil. The larva of P. brasiliensis can be distinguished from the two South American species of the genus with described larvae (P. clementia Selys and P. mutans Calvert), mainly by presence of a single obtuse cusp on the labial palp, the presence and configuration of setae in the caudal lamellae, and the proportional length of terminal filaments of the caudal lamellae. The family is recorded here for the first time in Brazilian state of Amazonas. PMID:27395963

  2. Toxicity of dissolved ozone to fish eggs and larvae

    SciTech Connect

    Asbury, C.; Coler, R.

    1980-07-01

    To find levels of dissolved residual ozone lethal to fish eggs and larvae during brief exposures, continuous-flow toxicity tests were performed with eggs and larvae of yellow perch (Perca flavescens), and fathead minnow (Pimephales promelas), eggs of white sucker (Catastomus commersoni), and larvae of bluegill sunfish (Lepomis macrochirus). The 50 and 99% lethal concentrations with confidence limits were calculated. Eggs of the species tested were more tolerant than larvae, which were destroyed by very brief exposures (less than 2 minutes) to residuals less than 0.1 mg/1. Because of the sensitivity of the larvae, residual ozone concentrations in natural waters should remain well below 50 ..mu..g/1.

  3. Cardiac involvement in dengue virus infections during the 2004/2005 dengue fever season in Sri Lanka.

    PubMed

    Wichmann, Dominic; Kularatne, Senanayake; Ehrhardt, Stephan; Wijesinghe, Sriyal; Brattig, Norbert W; Abel, Walter; Burchard, Gerd D

    2009-07-01

    Sri Lanka experienced a dramatic increase in dengue cases (15,400) in the 2004 - 2005 season. We carried out a prospective study to investigate cardiac involvement in dengue virus infected patients during the 2004 - 2005 season in Peradeniya, Central Province, Sri Lanka. Cardiac involvement was defined as elevated levels of myoglobin, creatine kinase-muscle brain-type, N-terminal pro-brain natriuretic peptide, heart-type fatty acid-binding protein and troponin T. Twenty-five percent of dengue virus infected patients had one or more of the above tests with abnormal results. PMID:19842405

  4. Dengue virus envelope protein domain I/II hinge: a key target for dengue virus vaccine design?

    PubMed

    Widman, Douglas G; Baric, Ralph S

    2015-01-01

    Dengue virus is the most significant arboviral pathogen worldwide with nearly 400 million infections annually and half the global population at risk of disease. Despite this tremendous public health burden, there are no licensed treatments or vaccines to prevent dengue in humans. Results from clinical trials of leading vaccine candidates have demonstrated that our current understanding of the correlates of protection from dengue is incomplete, and as such vaccine performance has been moderate, but with considerable room for improvement. Here we highlight new findings revealing key neutralizing epitopes that regulate serotype-specific immunity, and discuss their implications for design and evaluation of future vaccine candidates. PMID:25249440

  5. Cholesterol biosynthesis modulation regulates dengue viral replication.

    PubMed

    Rothwell, Christopher; Lebreton, Aude; Young Ng, Chuan; Lim, Joanne Y H; Liu, Wei; Vasudevan, Subhash; Labow, Mark; Gu, Feng; Gaither, L Alex

    2009-06-20

    We performed a focused siRNA screen in an A549 dengue type 2 New Guinea C subgenomic replicon cell line (Rluc-replicon) that contains a Renilla luciferase cassette. We found that siRNA mediated knock down of mevalonate diphospho decarboxylase (MVD) inhibited viral replication of the Rluc-replicon and DEN-2 NGC live virus replication in A549 cells. When the Rluc-replicon A459 cells were grown in delipidated media the replicon expression was suppressed and MVD knock down could further sensitize Renilla expression. Hymeglusin and zaragozic acid A could inhibit DEN-2 NGC live virus replication in K562 cells, while lovastatin could inhibit DEN-2 NGC live virus replication in human peripheral blood mononuclear cells. Renilla expression could be rescued in fluvastatin treated A549 Rluc-replicon cells after the addition of mevalonate, and partially restored with geranylgeranyl pyrophosphate, or farnesyl pyrophosphate. Our data suggest genetic and pharmacological modulation of cholesterol biosynthesis can regulate dengue virus replication. PMID:19419745

  6. Effect of Chloroxylon swietenia Dc bark extracts against Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi larvae.

    PubMed

    Balasubramanian, Jayaprasad; Subramanian, Sharavanan; Kaliyan, Veerakumar

    2015-11-01

    Mosquitoes are the vector of more diseases and cause major health problems like malaria, dengue, chikungunya, and lymphatic filariasis. This article deals with the mosquito larvicidal activity of Chloroxylon swietenia Dc bark extracts against late third instar larvae of Culex quinquefasciatus, Aedes aegypti, and Anopheles stephensi. Methanolic crude extract of Ch. swietenia bark was obtained by soxhlet apparatus and aqueous crude extract by cold percolation method. The range of concentrations of the crude extracts used was 50, 100, 150, 200, and 250 ppm. The mortality and lethal concentration (LC50 and LC90) was calculated after a 24-h exposure period. Both the extracts showed trustworthy larvicidal activity. The larvicidal activity of the methanol extract of Ch. swietenia bark was higher than the aqueous extract, and the LC50 and the LC90 values of the methanol extract were found to be 124.70 and 226.26 μg/ml (Ae. aegypti), 130.57 and 234.67 ppm (Cu. quinquefasciatus), and 137.55 and 246.09 ppm (An. stephensi). The LC50 and the LC90 values of the aqueous extract were found to be 133.10 and 238.93 ppm (Ae. aegypti), 136.45 and 242.47 ppm (Cu. quinquefasciatus), and 139.43 and 248.64 ppm (An. stephensi). No mortality was observed in the control. Methanolic crude extract Ch. swietenia bark shows higher activity against An. stephensi than the other two tested larvae and aqueous extract. The results of the present study propose a possible way for further investigations to find out the active molecule responsible for the larvicidal activity of Ch. swietenia bark extracts. PMID:26246308

  7. [The diagnosis of dengue in Mexico: an update and outlook].

    PubMed

    Zárate-Aquino, M L; del Río-Zolezzi, A; Gómez-Dantés, H

    1995-01-01

    Few diseases have unique clinical findings sufficient to identify them. Dengue fever is not one of them, being necessary the clinical and laboratory support to confirm its diagnosis. Since dengue virus was first isolated, there has been a worldwide effort to develop cheaper and more accurate serologic diagnostic tests. Dengue hemorrhagic fever deserves closer attention because of its devastating clinical effects and lethal outcomes. In addition to the wide circulation of serotypes 1, 2 and 4 for over a decade in the Americas, the presence of Den-3 was detected again in 1994 since its last appearance in 1963 and 1977. Given the high rates of vectorial infestation and the presence of a susceptible population, the probability of circulation of this serotype in our continent is high. The present work defines the wide range of diagnostic methods available today, their advantages and disadvantages, and their importance in the epidemiological surveillance of dengue fever in Mexico. PMID:8599145

  8. Dengue vaccine: an update on recombinant subunit strategies.

    PubMed

    Martin, J; Hermida, L

    2016-03-01

    Dengue is an increasing public health problem worldwide, with the four serotypes of the virus infecting over 390 million people annually. There is no specific treatment or antiviral drug for dengue, and prevention is largely limited to controlling the mosquito vectors or disrupting the human-vector contact. Despite the considerable progress made in recent years, an effective vaccine against the virus is not yet available. The development of a dengue vaccine has been hampered by many unique challenges, including the need to ensure the absence of vaccine-induced enhanced severity of disease. Recombinant protein subunit vaccines offer a safer alternative to other vaccine approaches. Several subunit vaccine candidates are presently under development, based on different structural and non-structural proteins of the virus. Novel adjuvants or immunopotentiating strategies are also being tested to improve their immunogenicity. This review summarizes the current status and development trends of subunit dengue vaccines. PMID:26982462

  9. Maculopathy associated with Dengue fever in a military pilot.

    PubMed

    Nah, Gerard; Tan, Marcus; Teoh, Stephen; Chong, Chun Hon

    2007-11-01

    Dengue fever is the most prevalent vector-borne flavivirus infection in humans. Its ocular manifestations have only recently been reported with increasing frequency. We present a case of an air force rotary wing pilot who presented with dengue-related maculopathy and decrement in visual function. The pilot ultimately recovered full visual function and was returned to full unrestricted flying duties with the proviso of regular ophthalmic monitoring. Dengue-related maculopathy may present with retinal edema, blot hemorrhages, and vasculitis. Less common features include exudative retinal detachment, cotton wool spots, and anterior uveitis. It is generally self-resolving with good prognosis. Treatment is controversial, but a course of corticosteroids has been tried in view of a postulated underlying immune-mediated pathology. It is recommended that aviators who have recovered from dengue fever undergo a clinical ophthalmological examination before return to flying duties. PMID:18018440

  10. Acute gingival bleeding as a complication of dengue hemorrhagic fever.

    PubMed

    Khan, Saif; Gupta, N D; Maheshwari, Sandhya

    2013-07-01

    Dengue fever is mosquito borne disease caused by dengue virus (DENV) of Flaviviridae family. The clinical manifestations range from fever to severe hemorrhage, shock and death. Here, we report a case of 20-year-old male patient undergoing orthodontic treatment presenting with acute gingival bleeding with a history of fever, weakness, backache, retro orbital pain and ecchymosis over his right arm. The hematological investigations revealed anemia, thrombocytopenia and positive dengue non-structural protein-1 antigen and also positive immunoglobulin M and immunoglobulin G antibodies for DENV. Patient was diagnosed as a case of dengue hemorrhagic fever and was immediately referred for appropriate management. This case report emphasizes the importance of taking correct and thorough medical history. PMID:24174736

  11. Risk mapping of dengue in Selangor and Kuala Lumpur, Malaysia.

    PubMed

    Hassan, Hafiz; Shohaimi, Shamarina; Hashim, Nor R

    2012-11-01

    Dengue fever is a recurring public health problem afflicting thousands of Malaysians annually. In this paper, the risk map for dengue fever in the peninsular Malaysian states of Selangor and Kuala Lumpur was modelled based on co-kriging and geographical information systems. Using population density and rainfall as the model's only input factors, the area with the highest risk for dengue infection was given as Gombak and Petaling, two districts located on opposite sides of Kuala Lumpur city that was also included in the risk assessment. Comparison of the modelled risk map with the dengue case dataset of 2010, obtained from the Ministry of Health of Malaysia, confirmed that the highest number of cases had been found in an area centred on Kuala Lumpur as predicted our risk profiling. PMID:23242677

  12. Epidemiology of Dengue among Children Aged < 18 Months—Puerto Rico, 1999–2011

    PubMed Central

    Hause, Anne M.; Perez-Padilla, Janice; Horiuchi, Kalanthe; Han, George S.; Hunsperger, Elizabeth; Aiwazian, Jonathan; Margolis, Harold S.; Tomashek, Kay M.

    2016-01-01

    Dengue, a mosquito-borne viral illness caused by dengue virus types (DENV)-1 to DENV-4, is endemic in Puerto Rico. Severe dengue usually occurs in individuals previously infected with DENV or among infants born to previously infected mothers. To describe clinical features of dengue in infants, we retrospectively characterized dengue patients aged < 18 months reported to the Passive Dengue Surveillance System (PDSS) during 1999–2011. To determine frequency of signs, symptoms, and disease severity, case report forms and medical records were evaluated for patients who tested positive for dengue by reverse transcriptase polymerase chain reaction or anti-DENV immunoglobulin Menzyme-linked immunosorbent assay. Of 4,178 reported patients aged < 18 months, 813 (19%) were laboratory positive. Of these, most had fever (92%), rash (53%), bleeding manifestations (52%), and thrombocytopenia (52%). Medical records were available for 145 (31%) of 472 hospitalized patients, of which 40% had dengue, 23% had dengue with warning signs, and 33% had severe dengue. Mean age of patients with severe dengue was 8 months. Anti-DENV immunoglobulin G (IgG) titers were not statistically different in patients with (50%) and without (59%) severe dengue. In this study, one-third of DENV-infected infants met the severe dengue case definition. The role of maternal anti-DENV IgG in development of severe disease warrants further study in prospective cohorts of mother-infant pairs. PMID:26711519

  13. Hot spot detection and spatio-temporal dynamics of dengue in Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Naish, S.; Tong, S.

    2014-11-01

    Dengue has been a major public health concern in Australia since it re-emerged in Queensland in 1992-1993. This study explored spatio-temporal distribution and clustering of locally-acquired dengue cases in Queensland State, Australia and identified target areas for effective interventions. A computerised locally-acquired dengue case dataset was collected from Queensland Health for Queensland from 1993 to 2012. Descriptive spatial and temporal analyses were conducted using geographic information system tools and geostatistical techniques. Dengue hot spots were detected using SatScan method. Descriptive spatial analysis showed that a total of 2,398 locally-acquired dengue cases were recorded in central and northern regions of tropical Queensland. A seasonal pattern was observed with most of the cases occurring in autumn. Spatial and temporal variation of dengue cases was observed in the geographic areas affected by dengue over time. Tropical areas are potential high-risk areas for mosquito-borne diseases such as dengue. This study demonstrated that the locally-acquired dengue cases have exhibited a spatial and temporal variation over the past twenty years in tropical Queensland, Australia. There is a clear evidence for the existence of statistically significant clusters of dengue and these clusters varied over time. These findings enabled us to detect and target dengue clusters suggesting that the use of geospatial information can assist the health authority in planning dengue control activities and it would allow for better design and implementation of dengue management programs.

  14. Role of Humoral versus Cellular Responses Induced by a Protective Dengue Vaccine Candidate

    PubMed Central

    Zellweger, Raphaël M.; Miller, Robyn; Eddy, William E.; White, Laura J.; Johnston, Robert E.; Shresta, Sujan

    2013-01-01

    With 2.5 billion people at risk, dengue is a major emerging disease threat and an escalating public health problem worldwide. Dengue virus causes disease ranging from a self-limiting febrile illness (dengue fever) to the potentially fatal dengue hemorrhagic fever/dengue shock syndrome. Severe dengue disease is associated with sub-protective levels of antibody, which exacerbate disease upon re-infection. A dengue vaccine should generate protective immunity without increasing severity of disease. To date, the determinants of vaccine-mediated protection against dengue remain unclear, and additional correlates of protection are urgently needed. Here, mice were immunized with viral replicon particles expressing the dengue envelope protein ectodomain to assess the relative contribution of humoral versus cellular immunity to protection. Vaccination with viral replicon particles provided robust protection against dengue challenge. Vaccine-induced humoral responses had the potential to either protect from or exacerbate dengue disease upon challenge, whereas cellular immune responses were beneficial. This study explores the immunological basis of protection induced by a dengue vaccine and suggests that a safe and efficient vaccine against dengue should trigger both arms of the immune system. PMID:24204271

  15. Epidemiology of Dengue Among Children Aged < 18 Months-Puerto Rico, 1999-2011.

    PubMed

    Hause, Anne M; Perez-Padilla, Janice; Horiuchi, Kalanthe; Han, George S; Hunsperger, Elizabeth; Aiwazian, Jonathan; Margolis, Harold S; Tomashek, Kay M

    2016-02-01

    Dengue, a mosquito-borne viral illness caused by dengue virus types (DENV)-1 to DENV-4, is endemic in Puerto Rico. Severe dengue usually occurs in individuals previously infected with DENV or among infants born to previously infected mothers. To describe clinical features of dengue in infants, we retrospectively characterized dengue patients aged < 18 months reported to the Passive Dengue Surveillance System (PDSS) during 1999-2011. To determine frequency of signs, symptoms, and disease severity, case report forms and medical records were evaluated for patients who tested positive for dengue by reverse transcriptase polymerase chain reaction or anti-DENV immunoglobulin Menzyme-linked immunosorbent assay. Of 4,178 reported patients aged < 18 months, 813 (19%) were laboratory positive. Of these, most had fever (92%), rash (53%), bleeding manifestations (52%), and thrombocytopenia (52%). Medical records were available for 145 (31%) of 472 hospitalized patients, of which 40% had dengue, 23% had dengue with warning signs, and 33% had severe dengue. Mean age of patients with severe dengue was 8 months. Anti-DENV immunoglobulin G (IgG) titers were not statistically different in patients with (50%) and without (59%) severe dengue. In this study, one-third of DENV-infected infants met the severe dengue case definition. The role of maternal anti-DENV IgG in development of severe disease warrants further study in prospective cohorts of mother-infant pairs. PMID:26711519

  16. Encysted parasitic larvae in the mouth.

    PubMed

    Hansen, L S; Allard, R H

    1984-04-01

    Oral appearances of intestinal parasitic disease are rare. One such appearance is the presence in oral tissues of encysted or encapsulated larvae of organisms from the classes Cestoidea and Nematoda. Cestode larvae form cyst-like lesions that are often clinically diagnosed as mucoceles. In these lesions, the cyst cavity is lined by fibrous tissue with inflammatory cells, and contains fluid and the larval stage of a parasite. The diagnosis of these parasitic cysts is more frequently made in younger persons. The cysts may be treated by simple excision, but care must be taken that the cyst does not rupture, as in some parasites this may result in new cyst formation. Nematode infection in the oral cavity, the most common of which appears to be trichinosis, is rarely reported. Patients with oral or maxillofacial (or both) parasitic disease must undergo a thorough medical investigation to exclude possible life-threatening involvement in other parts of the body. PMID:6586809

  17. Visceral larva migrans (toxocariasis) in Toronto.

    PubMed Central

    Fanning, M; Hill, A; Langer, H M; Keystone, J S

    1981-01-01

    A 7-year-old child was admitted to Toronto's Hospital for Sick Children in 1976 with symptoms and laboratory findings compatible with visceral larva migrans, a disease usually caused by Toxocara canis. This prompted a search for other cases seen at the hospital during the period 1952 through 1978. Only 18 cases were discovered that met at least three of six criteria and thus were considered possible or probably cases of the disease. Three possible cases of ocular toxocariasis during the same period were also uncovered. Fever was the commonest presenting symptom. Eosinophilia, leukocytosis and hyperglobulinemia were the most frequent laboratory findings. In view of the small number of cases found in 27 years at this large pediatric hospital with a broad referral base, it is concluded that visceral larva migrans poses little risk to the health of children in the Toronto area. PMID:7459767

  18. Vaccines for the prevention of neglected diseases--dengue fever.

    PubMed

    Pang, Tikki

    2003-06-01

    Dengue and dengue hemorrhagic fever have spread to all tropical areas of the developing world, but still remain largely neglected diseases. Several promising vaccine candidates in the form of live attenuated and chimeric vaccines have been developed and are currently in human clinical trials. However, significant practical, logistic, and scientific challenges remain before these vaccines can widely and safely be applied to vulnerable populations. Vector control, community education and public health measures must be pursued in parallel with vaccine development. PMID:12849789

  19. Households as Foci for Dengue Transmission in Highly Urban Vietnam

    PubMed Central

    Anders, Katherine L.; Nga, Le Hong; Thuy, Nguyen Thi Van; Ngoc, Tran Van; Tam, Cao Thi; Tai, Luong Thi Hue; Truong, Nguyen Thanh; Duyen, Huynh Thi Le; Trung, Vu Tuan; Kien, Duong Thi Hue; Wolbers, Marcel; Wills, Bridget; Chau, Nguyen Van Vinh; Tho, Nguyen Dac; Simmons, Cameron P.

    2015-01-01

    Background Dengue control programs commonly employ reactive insecticide spraying around houses of reported cases, with the assumption that most dengue virus (DENV) transmission occurs in the home. Focal household transmission has been demonstrated in rural settings, but it is unclear whether this holds true in dense and mobile urban populations. We conducted a prospective study of dengue clustering around households in highly urban Ho Chi Minh City, Vietnam. Methods We enrolled 71 index cases with suspected dengue (subsequently classified as 52 dengue cases and 19 non-dengue controls); each initiated the enrollment of a cluster of 25–35 household members and neighbors who were followed up over 14 days. Incident DENV infections in cluster participants were identified by RT-PCR, NS1-ELISA, and/or DENV-IgM/-IgG seroconversion, and recent infections by DENV-IgM positivity at baseline. Principal Findings/Conclusions There was no excess risk of DENV infection within dengue case clusters during the two-week follow-up, compared to control clusters, but the prevalence of recent DENV infection at baseline was two-fold higher in case clusters than controls (OR 2.3, 95%CI 1.0–5.1, p = 0.05). Prevalence of DENV infection in Aedes aegypti was similar in case and control houses, and low overall (1%). Our findings are broadly consistent with household clustering of dengue risk, but indicate that any clustering is at a short temporal scale rather than sustained chains of localized transmission. This suggests that reactive perifocal insecticide spraying may have a limited impact in this setting. PMID:25680106

  20. DENGUE DURING PREGNANCY: ASSOCIATION WITH LOW BIRTH WEIGHT AND PREMATURITY

    PubMed Central

    RIBEIRO, Christiane Fernandes; LOPES, Vânia Glória Silami; Brasil, Patricia; da Silva, Licinio Esmeraldo; RIBEIRO, Pedro Henrique Fernandes Josephson; UGENTI, Luca Cipriani; NOGUEIRA, Rita Maria Ribeiro

    2016-01-01

    The aim of this study was to evaluate the effects of dengue virus infection during pregnancy and its correlation with low birth weight, prematurity, and asphyxia. A non-concurrent cohort study reveals the association of dengue during pregnancy with prematurity and low birth weight, when birth occurred during the maternal-fetal viremia period (p = 0.016 and p < 0.0001, respectively). PMID:26910454

  1. Prevention and control of influenza and dengue through vaccine development.

    PubMed

    Greenberg, David P; Robertson, Corwin A; Gordon, Daniel M

    2013-08-01

    Influenza and dengue are viral illnesses of global public health importance, especially among children. Accordingly, these diseases have been the focus of efforts to improve their prevention and control. Influenza vaccination offers the best protection against clinical disease caused by strains contained within the specific year's formulation. It is not uncommon for there to be a mismatch between vaccine strains and circulating strains, particularly with regards to the B lineages. For more than a decade, two distinct lineages of influenza B (Yamagata and Victoria) have co-circulated in the US with varying frequencies, but trivalent influenza vaccines contain only one B-lineage strain and do not offer adequate protection against the alternate B-lineage. Quadrivalent influenza vaccines (QIVs), containing two A strains (H1N1 and H3N2) and two B strains (one from each lineage) have been developed to help protect against the four strains predicted to be the most likely to be circulating. The QIV section of this article discusses epidemiology of pediatric influenza, importance of influenza B in children, potential benefits of QIV, and new quadrivalent vaccines. In contrast to influenza, a vaccine against dengue is not yet available in spite of many decades of research and development. A global increase in reports of dengue fever (DF) and its more severe presentations, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), suggest that US physicians will increasingly encounter patients with this disease. Similarities of the early signs and symptoms of influenza and dengue and the differences in disease management necessitates a better understanding of the epidemiology, clinical presentation, management, and prevention of DF by US physicians, including pediatricians. The article also provides a brief overview of dengue and discusses dengue vaccine development. PMID:23910031

  2. Assessing Weather Effects on Dengue Disease in Malaysia

    PubMed Central

    Cheong, Yoon Ling; Burkart, Katrin; Leitão, Pedro J.; Lakes, Tobia

    2013-01-01

    The number of dengue cases has been increasing on a global level in recent years, and particularly so in Malaysia, yet little is known about the effects of weather for identifying the short-term risk of dengue for the population. The aim of this paper is to estimate the weather effects on dengue disease accounting for non-linear temporal effects in Selangor, Kuala Lumpur and Putrajaya, Malaysia, from 2008 to 2010. We selected the weather parameters with a Poisson generalized additive model, and then assessed the effects of minimum temperature, bi-weekly accumulated rainfall and wind speed on dengue cases using a distributed non-linear lag model while adjusting for trend, day-of-week and week of the year. We found that the relative risk of dengue cases is positively associated with increased minimum temperature at a cumulative percentage change of 11.92% (95% CI: 4.41–32.19), from 25.4 °C to 26.5 °C, with the highest effect delayed by 51 days. Increasing bi-weekly accumulated rainfall had a positively strong effect on dengue cases at a cumulative percentage change of 21.45% (95% CI: 8.96, 51.37), from 215 mm to 302 mm, with the highest effect delayed by 26–28 days. The wind speed is negatively associated with dengue cases. The estimated lagged effects can be adapted in the dengue early warning system to assist in vector control and prevention plan. PMID:24287855

  3. Locally acquired Dengue--Key West, Florida, 2009-2010.

    PubMed

    2010-05-21

    Dengue is the most common vector-borne viral disease in the world, causing an estimated 50-100 million infections and 25,000 deaths each year. During 1946-1980, no cases of dengue acquired in the continental United States were reported. Since 1980, a few locally acquired U.S. cases have been confirmed along the Texas-Mexico border, temporally associated with large outbreaks in neighboring Mexican cities. On September 1, 2009, a New York physician notified the Monroe County (Florida) Health Department (MCHD) and the Florida Department of Health (FDOH) of a suspected dengue case in a New York state resident whose only recent travel was to Key West, Florida. CDC confirmed the diagnosis, and a press release was issued to notify the public and Key West physicians of the potential risk for locally acquired dengue infections. In the next 2 weeks, two dengue infections in Key West residents without recent travel were reported and confirmed. Subsequently, enhanced and active surveillance identified 24 more Key West cases during 2009. On April 13, 2010, another Key West dengue case was reported to FDOH, bringing the total to 28. This report describes the first three dengue cases reported in 2009, briefly summarizes the 2010 case, highlights preliminary findings from the ongoing investigation, and outlines measures used to mitigate and control the outbreak. Clinicians should include dengue in the differential diagnosis of acute febrile illnesses in patients who live in or have recently traveled to subtropical areas of the United States or to the tropics. PMID:20489680

  4. Dengue Virus Structural Differences That Correlate with Pathogenesis

    PubMed Central

    Leitmeyer, Katrin C.; Vaughn, David W.; Watts, Douglas M.; Salas, Rosalba; Villalobos , Iris; de Chacon; Ramos, Celso; Rico-Hesse, Rebeca

    1999-01-01

    The understanding of dengue virus pathogenesis has been hampered by the lack of in vitro and in vivo models of disease. The study of viral factors involved in the production of severe dengue, dengue hemorrhagic fever (DHF), versus the more common dengue fever (DF), have been limited to indirect clinical and epidemiologic associations. In an effort to identify viral determinants of DHF, we have developed a method for comparing dengue type 2 genomes (reverse transcriptase PCR in six fragments) directly from patient plasma. Samples for comparison were selected from two previously described dengue type 2 genotypes which had been shown to be the cause of DF or DHF. When full genome sequences of 11 dengue viruses were analyzed, several structural differences were seen consistently between those associated with DF only and those with the potential to cause DHF: a total of six encoded amino acid charge differences were seen in the prM, E, NS4b, and NS5 genes, while sequence differences observed within the 5′ nontranslated region (NTR) and 3′ NTR were predicted to change RNA secondary structures. We hypothesize that the primary determinants of DHF reside in (i) amino acid 390 of the E protein, which purportedly alters virion binding to host cells; (ii) in the downstream loop (nucleotides 68 to 80) of the 5′ NTR, which may be involved in translation initiation; and (iii) in the upstream 300 nucleotides of the 3′ NTR, which may regulate viral replication via the formation of replicative intermediates. The significance of four amino acid differences in the nonstructural proteins NS4b and NS5, a presumed transport protein and the viral RNA polymerase, respectively, remains unknown. This new approach to the study of dengue virus genome differences should better reflect the true composition of viral RNA populations in the natural host and permit their association with pathogenesis. PMID:10233934

  5. A preliminary study of dengue infection in Brunei.

    PubMed

    Osman, Osmali; Fong, Mun Yik; Devi, Shamala

    2007-07-01

    The purpose of this study was to examine the extent of dengue infection in Brunei and to determine the predominant serotype circulating in the country. The study generated useful epidemiological data on dengue infection in Brunei. A total of 271 samples from patients suspected of having dengue infections were selected and analyzed. All patients were seen in clinics and hospitals in Brunei. The samples were collected from April 2005 to April 2006 and transported to the WHO Collaborating Centre for Arbovirus Reference and Research, University of Malaya, Malaysia. The following tests were used to achieve the objectives: in-house IgM-capture enzyme-linked immunosorbent assay, virus isolation in mosquito albopictus cell line (C6/36), and viral RNA detection and serotyping by reverse transcriptase-polymerase chain reaction (RT-PCR). The results show that 45 people were positive for dengue-specific IgM (27 males and 18 females), while RT-PCR detected dengue viral RNA in 12 patients, 3 identified as DEN-1 and 9 as DEN-2. Dengue virus was isolated from 6 patients using the C6/36 cell line; 3 were DEN-2 isolates and 3 were DEN-1 isolates. These data show that dengue virus is circulating in Brunei and the predominant infecting serotype for that period was DEN-2 followed by DEN-1. This study is the first to report the detection and isolation of dengue virus from Brunei using RT-PCR and culture in the C6/36 albopictus mosquito cell line. PMID:17642533

  6. Hemophagocytic Lymphohistiocytosis Complicating Dengue and Plasmodium vivax Coinfection

    PubMed Central

    Khurram, Muhammad; Faheem, Muhammad; Umar, Muhammad; Yasin, Asif; Qayyum, Wajeeha; Ashraf, Amna; Zahid Khan, Javeria; Hasnain Yasir, Ali; Ansari, Yusra; Asad, Muhammad; Khan, Iram; Abbas, Shuja; Rasheed, Irum; Rasool, Natasha; Bushra Khar, Hamama Tul

    2015-01-01

    Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder. Dysfunction of cytotoxic T and natural killer (NK) cells causes uncontrolled activity of lymphocytes and histiocytes which leads to HLH. Infections, malignancies, and autoimmune disorders are associated with development of HLH. Dengue and Plasmodium vivax are rare causes of HLH. We report the first ever case of a young man who developed fatal HLH that complicated Dengue Hemorrhagic Fever (DHF) and Plasmodium vivax infection. PMID:26504465

  7. The Hidden Burden of Dengue and Chikungunya in Chennai, India

    PubMed Central

    Rodríguez-Barraquer, Isabel; Solomon, Sunil S.; Kuganantham, Periaswamy; Srikrishnan, Aylur Kailasom; Vasudevan, Canjeevaram K.; Iqbal, Syed H.; Balakrishnan, Pachamuthu; Solomon, Suniti; Mehta, Shruti H.; Cummings, Derek A. T.

    2015-01-01

    Background Dengue and chikungunya are rapidly expanding viruses transmitted by mosquitoes of the genus Aedes. Few epidemiological studies have examined the extent of transmission of these infections in South India despite an increase in the number of reported cases, and a high suitability for transmission. Methods and findings We conducted a household-based seroprevalence survey among 1010 individuals aged 5-40 years living in fifty randomly selected spatial locations in Chennai, Tamil Nadu. Participants were asked to provide a venous blood sample and to complete a brief questionnaire with basic demographic and daily activity information. Previous exposure to dengue and chikungunya was determined using IgG indirect ELISA (Panbio) and IgG ELISA (Novatec), respectively. We used this data to estimate key transmission parameters (force of infection and basic reproductive number) and to explore factors associated with seropositivity. While only 1% of participants reported history of dengue and 20% of chikungunya, we found that 93% (95%CI 89-95%) of participants were seropositive to dengue virus, and 44% (95%CI 37-50%) to chikungunya. Age-specific seroprevalence was consistent with long-tem, endemic circulation of dengue and suggestive of epidemic chikungunya transmission. Seropositivity to dengue and chikungunya were significantly correlated, even after adjusting for individual and household factors. We estimate that 23% of the susceptible population gets infected by dengue each year, corresponding to approximately 228,000 infections. This transmission intensity is significantly higher than that estimated in known hyperendemic settings in Southeast Asia and the Americas. Conclusions These results provide unprecedented insight into the very high transmission potential of dengue and chikungunya in Chennai and underscore the need for enhanced surveillance and control methods. PMID:26181441

  8. The early stress responses in fish larvae.

    PubMed

    Pederzoli, Aurora; Mola, Lucrezia

    2016-05-01

    During the life cycle of fish the larval stages are the most interesting and variable. Teleost larvae undergo a daily increase in adaptability and many organs differentiate and become active. These processes are concerted and require an early neuro-immune-endocrine integration. In larvae communication among the nervous, endocrine and immune systems utilizes several known signal molecule families which could be different from those of the adult fish. The immune-neuroendocrine system was studied in several fish species, among which in particular the sea bass (Dicentrarchus labrax), that is a species of great commercial interest, very important in aquaculture and thus highly studied. Indeed the immune system of this species is the best known among marine teleosts. In this review the data on main signal molecules of stress carried out on larvae of fish are considered and discussed. For sea bass active roles in the early immunological responses of some well-known molecules involved in the stress, such as ACTH, nitric oxide, CRF, HSP-70 and cortisol have been proposed. These molecules and/or their receptors are biologically active mainly in the gut before complete differentiation of gut-associated lymphoid tissue (GALT), probably acting in an autocrine/paracrine way. An intriguing idea emerges from all results of these researches; the molecules involved in stress responses, expressed in the adult cells of the hypothalamic-pituitary axis, during the larval life of fish are present in several other localizations, where they perform probably the same role. It may be hypothesized that the functions performed by hypothalamic-pituitary system are particularly important for the survival of the larva and therefore they comprises several other localizations of body. Indeed the larval stages of fish are very crucial phases that include many physiological changes and several possible stress both internal and environmental. PMID:26968620

  9. TARGETTED RELEASE AND FRACTIONATION REVEAL GLUCURONYLATED AND SULPHATED N- AND O-GLYCANS IN LARVAE OF DIPTERAN INSECTS

    PubMed Central

    Kurz, Simone; Aoki, Kazuhiro; Jin, Chunsheng; Karlsson, Niclas G.; Tiemeyer, Michael; Wilson, Iain B.H.; Paschinger, Katharina

    2016-01-01

    Mosquitoes are important vectors of parasitic and viral diseases with Anopheles gambiae transmitting malaria and Aedes aegypti spreading yellow and Dengue fevers. Using two different approaches (solid-phase extraction and reversed-phase or hydrophilic interaction HPLC fractionation followed by MALDI-TOF MS or permethylation followed by NSI-MS), we examined the N-glycans of both A. gambiae and A. aegypti larvae and demonstrate the presence of a range of paucimannosidic glycans as well as bi- and tri-antennary glycans, some of which are modified with fucose or with sulphate or glucuronic acid residues; the latter anionic modifications were also found on N-glycans of larvae from another dipteran species (Drosophila melanogaster). The sulphate groups are attached primarily to core α-mannose residues (especially the α1,6-linked mannose), whereas the glucuronic acid residues are linked to non-reducing β1,3-galactose. Also, O-glycans were found to possess glucuronic acid and sulphate as well as phosphoethanolamine modifications. The presence of sulphated and glucuronylated N-glycans is a novel feature in dipteran glycomes; these structures have the potential to act as additional anionic glycan ligands involved in parasite interactions with the vector host. PMID:26047717

  10. Caffeine Taste Signaling in Drosophila Larvae

    PubMed Central

    Apostolopoulou, Anthi A.; Köhn, Saskia; Stehle, Bernhard; Lutz, Michael; Wüst, Alexander; Mazija, Lorena; Rist, Anna; Galizia, C. Giovanni; Lüdke, Alja; Thum, Andreas S.

    2016-01-01

    The Drosophila larva has a simple peripheral nervous system with a comparably small number of sensory neurons located externally at the head or internally along the pharynx to assess its chemical environment. It is assumed that larval taste coding occurs mainly via external organs (the dorsal, terminal, and ventral organ). However, the contribution of the internal pharyngeal sensory organs has not been explored. Here we find that larvae require a single pharyngeal gustatory receptor neuron pair called D1, which is located in the dorsal pharyngeal sensilla, in order to avoid caffeine and to associate an odor with caffeine punishment. In contrast, caffeine-driven reduction in feeding in non-choice situations does not require D1. Hence, this work provides data on taste coding via different receptor neurons, depending on the behavioral context. Furthermore, we show that the larval pharyngeal system is involved in bitter tasting. Using ectopic expressions, we show that the caffeine receptor in neuron D1 requires the function of at least four receptor genes: the putative co-receptors Gr33a, Gr66a, the putative caffeine-specific receptor Gr93a, and yet unknown additional molecular component(s). This suggests that larval taste perception is more complex than previously assumed already at the sensory level. Taste information from different sensory organs located outside at the head or inside along the pharynx of the larva is assembled to trigger taste guided behaviors. PMID:27555807

  11. Caffeine Taste Signaling in Drosophila Larvae.

    PubMed

    Apostolopoulou, Anthi A; Köhn, Saskia; Stehle, Bernhard; Lutz, Michael; Wüst, Alexander; Mazija, Lorena; Rist, Anna; Galizia, C Giovanni; Lüdke, Alja; Thum, Andreas S

    2016-01-01

    The Drosophila larva has a simple peripheral nervous system with a comparably small number of sensory neurons located externally at the head or internally along the pharynx to assess its chemical environment. It is assumed that larval taste coding occurs mainly via external organs (the dorsal, terminal, and ventral organ). However, the contribution of the internal pharyngeal sensory organs has not been explored. Here we find that larvae require a single pharyngeal gustatory receptor neuron pair called D1, which is located in the dorsal pharyngeal sensilla, in order to avoid caffeine and to associate an odor with caffeine punishment. In contrast, caffeine-driven reduction in feeding in non-choice situations does not require D1. Hence, this work provides data on taste coding via different receptor neurons, depending on the behavioral context. Furthermore, we show that the larval pharyngeal system is involved in bitter tasting. Using ectopic expressions, we show that the caffeine receptor in neuron D1 requires the function of at least four receptor genes: the putative co-receptors Gr33a, Gr66a, the putative caffeine-specific receptor Gr93a, and yet unknown additional molecular component(s). This suggests that larval taste perception is more complex than previously assumed already at the sensory level. Taste information from different sensory organs located outside at the head or inside along the pharynx of the larva is assembled to trigger taste guided behaviors. PMID:27555807

  12. Molecular detection of marine invertebrate larvae.

    PubMed

    Goffredi, Shana K; Jones, William J; Scholin, Christopher A; Marin, Roman; Vrijenhoek, Robert C

    2006-01-01

    The ecological patterns of many invertebrate larvae remain an ongoing mystery, in large part owing to the difficult task of detecting them in the water column. The development of nucleic-acid-based technology has the potential to resolve this issue by direct identification and monitoring of embryonic and larval forms in situ. We report herein on the successful development and application of nucleic-acid-based sandwich hybridization assays that detect barnacles using rRNA-targeted probes with both group-(order Thoracica) and species-(Balanus glandula) specificity. Primary results include the determination of target 18S rRNA sequences and the construction of "capture" probes for detection of larvae using hybridization techniques. In addition, we modified existing protocols for whole cell hybridization of invertebrate larvae as confirmation of the sandwich hybridization results. We used both hybridization techniques successfully in the laboratory on a plankton time series collected over 3 months, as well as a week-long in situ deployment of the technique in Monterey Bay, CA. The adaptability of this technology promises to be further applicable to various organisms and could be used to enhance our understanding of larval presence in the world's oceans. PMID:16380809

  13. Economic Cost and Burden of Dengue in the Philippines

    PubMed Central

    Edillo, Frances E.; Halasa, Yara A.; Largo, Francisco M.; Erasmo, Jonathan Neil V.; Amoin, Naomi B.; Alera, Maria Theresa P.; Yoon, In-Kyu; Alcantara, Arturo C.; Shepard, Donald S.

    2015-01-01

    Dengue, the world's most important mosquito-borne viral disease, is endemic in the Philippines. During 2008–2012, the country's Department of Health reported an annual average of 117,065 dengue cases, placing the country fourth in dengue burden in southeast Asia. This study estimates the country's annual number of dengue episodes and their economic cost. Our comparison of cases between active and passive surveillance in Punta Princesa, Cebu City yielded an expansion factor of 7.2, close to the predicted value (7.0) based on the country's health system. We estimated an annual average of 842,867 clinically diagnosed dengue cases, with direct medical costs (in 2012 US dollars) of $345 million ($3.26 per capita). This is 54% higher than an earlier estimate without Philippines-specific costs. Ambulatory settings treated 35% of cases (representing 10% of direct costs), whereas inpatient hospitals served 65% of cases (representing 90% of direct costs). The economic burden of dengue in the Philippines is substantial. PMID:25510723

  14. Dengue fever as a cause of hemophagocytic lymphohistiocytosis

    PubMed Central

    Hein, Noely; Moura, Nathalie Bianchini Vieira; Cardoso, Débora Morais; Hirose, Maki; Ferronato, Angela Espósito; Pastorino, Antônio Carlos; Lo, Denise Swei; Gilio, Alfredo Elias

    2015-01-01

    Dengue is endemic in more than 100 countries in Southeast Asia, the Americas, the western Pacific, Africa and the eastern Mediterranean regions. The virus is transmitted by Aedes mosquitoes. Dengue disease is the most prevalent arthropod-borne viral disease in humans and is a global and national public health concern in several countries. A seasonal pattern of dengue disease is consistently observed. The highest incidences usually correspond to the period of highest rainfall and humidity, providing suitable conditions for Aedes aegypti breeding and survival. In Brazil for instance it is from January to June. Dengue may cause marked changes in bone marrow that result in hypocellularity and, consequently, thrombocytopenia and leucopenia, along with an increase in hematocrit, which is secondary to capillary leakage. However, those abnormalities are usually self-limited, and do not warrant further investigations, such as a marrow biopsy or a myelogram. The occurrence of persistent reactive hemophagocytosis is uncommon and usually leads to serious adverse outcomes. The authors report the case of an 8-year old girl complaining of high-grade fever, malaise, headache, abdominal pain and a cutaneous rash. Laboratory examination revealed atypical lymphocytosis on peripheral blood count, hyperbilirrunemia, abnormal liver enzymes and clotting tests. Serology was positive for dengue. Because of the persistence of fever and laboratory examinations were consistent with hemophagocytic lymphohistiocytosis (HLH) a bone marrow aspiration was performed, which confirmed the presence of hemophagocytosis. Hence we report a rare presentation of dengue accompanied by self-limited HLH that hopefully evolve to favorable outcome. PMID:26558245

  15. Describing the Breakbone Fever: IDODEN, an Ontology for Dengue Fever

    PubMed Central

    Mitraka, Elvira; Topalis, Pantelis; Dritsou, Vicky; Dialynas, Emmanuel; Louis, Christos

    2015-01-01

    Background Ontologies represent powerful tools in information technology because they enhance interoperability and facilitate, among other things, the construction of optimized search engines. To address the need to expand the toolbox available for the control and prevention of vector-borne diseases we embarked on the construction of specific ontologies. We present here IDODEN, an ontology that describes dengue fever, one of the globally most important diseases that are transmitted by mosquitoes. Methodology/Principal Findings We constructed IDODEN using open source software, and modeled it on IDOMAL, the malaria ontology developed previously. IDODEN covers all aspects of dengue fever, such as disease biology, epidemiology and clinical features. Moreover, it covers all facets of dengue entomology. IDODEN, which is freely available, can now be used for the annotation of dengue-related data and, in addition to its use for modeling, it can be utilized for the construction of other dedicated IT tools such as decision support systems. Conclusions/Significance The availability of the dengue ontology will enable databases hosting dengue-associated data and decision-support systems for that disease to perform most efficiently and to link their own data to those stored in other independent repositories, in an architecture- and software-independent manner. PMID:25646954

  16. Dengue Virus Infection Perturbs Lipid Homeostasis in Infected Mosquito Cells

    SciTech Connect

    Perera, Rushika M.; Riley, Catherine; Isaac, Georgis; Hopf- Jannasch, Amber; Moore, Ronald J.; Weitz, Karl K.; Pasa-Tolic, Ljiljana; Metz, Thomas O.; Adamec, Jiri; Kuhn, Richard J.

    2012-03-22

    Dengue virus causes {approx}50-100 million infections per year and thus is considered one of the most aggressive arthropod-borne human pathogen worldwide. During its replication, dengue virus induces dramatic alterations in the intracellular membranes of infected cells. This phenomenon is observed both in human and vector-derived cells. Using high-resolution mass spectrometry of mosquito cells, we show that this membrane remodeling is directly linked to a unique lipid repertoire induced by dengue virus infection. Specifically, 15% of the metabolites detected were significantly different between DENV infected and uninfected cells while 85% of the metabolites detected were significantly different in isolated replication complex membranes. Furthermore, we demonstrate that intracellular lipid redistribution induced by the inhibition of fatty acid synthase, the rate-limiting enzyme in lipid biosynthesis, is sufficient for cell survival but is inhibitory to dengue virus replication. Lipids that have the capacity to destabilize and change the curvature of membranes as well as lipids that change the permeability of membranes are enriched in dengue virus infected cells. Several sphingolipids and other bioactive signaling molecules that are involved in controlling membrane fusion, fission, and trafficking as well as molecules that influence cytoskeletal reorganization are also up regulated during dengue infection. These observations shed light on the emerging role of lipids in shaping the membrane and protein environments during viral infections and suggest membrane-organizing principles that may influence virus-induced intracellular membrane architecture.

  17. Correlation of Clinicohaematological Parameters in Paediatric Dengue: A Retrospective Study

    PubMed Central

    Pai Jakribettu, Ramakrishna; Boloor, Rekha; Thaliath, Andrew; Yesudasan George, Sharanya; George, Thomas; Ponadka Rai, Manoj; Rafique Sheikh, Umran; Avabratha, Kadke Shreedhara; Baliga, Manjeshwar Shrinath

    2015-01-01

    Dengue is one of the arthropod-borne (arbo) viral diseases transmitted by female mosquito Aedes aegypti. Dengue fever has a wide spectrum of clinical presentation ranging from flu-like illness to severe complicated stage of dengue hemorrhagic fever leading to mortality. This was a retrospective study conducted in a tertiary care hospital in Coastal Karnataka, South India, to know the correlation between the clinical presentation and haematological parameters in the paediatric cases presented with dengue symptoms. A total of 163 paediatric cases who presented fever and dengue-like illness were included in the study. Of which, 69 were confirmed dengue patients. Critical analysis showed that there was a significant difference in the haematological parameters like total leucocyte count, percent differential leucocyte count, and platelets count, in the erythrocyte sedimentation rate (P < 0.05 to 0.0001). Additionally, when compared to nondengue patients, even the liver function and renal function parameters were significantly deranged (P < 0.05 to 0.0001). Stratification based on NS1, IgG, and IgM showed significant alterations in the haematological, hepatic, and renal parameters. With respect to the treatment a small percentage of patients, that is, 8% (4 patients), required platelet transfusion as their counts went below 20,000/μL. Two patients succumbed to their illness while three required ICU stay. PMID:26819620

  18. [Dengue fever--not just a tropical infectious disease].

    PubMed

    Stock, Ingo

    2016-03-01

    Dengue fever is a viral disease that is transmitted primarily by Aedes mosquitoes, i. e., A. aegypti and A. albopictus. Other species are rarely involved. The disease is caused by dengue virus, an enveloped RNA virus which belongs to the family of flaviviridae. Although most infections are asymptomatic, in 20 to 30 percentages all cases infections are accompanied with high fever and other influenza-like signs of illness. Serious medical conditions with lethal complications also occur. During the last decades, the incidence of dengue fever rose sharply in many tropical and subtropical countries. In some of these regions, dengue is one of the leading causes of death in children. In Europe, since a few years a strong clustering of dengue fever cases has been registered in travelers returning from certain tropical or subtropical regions. Recently, autochthonous outbreaks have been observed on the Atlantic island of Madeira and in a few other regions of South Europe. Treatment of dengue fever is supportive and symptomatic, a specific therapy does not exist. For prevention of disease, vector control is of crucial importance. PMID:27120872

  19. Analysis of the dengue disease model with two virus strains

    NASA Astrophysics Data System (ADS)

    Adi-Kusumo, F.; Aini, A. N.; Ridwan, M.

    2014-02-01

    Dengue fever (DF) and dengue haemorrhagic fever (DHF) are the disease caused by the dengue virus which is transmitted to the human by infected female mosquitoes. The disease is endemic in more than 100 countries over the world. Dengue virus has four distinct serotypes which are closely related to each other antigenically. A person who infected by the dengue virus will never be infected again by the same serotype, but he looses immunity from the three other serotypes. Infection with one serotype does not provide cross-protective immunity against to others. Here we assume that there are two serotypes exist in the population. Someone who has recovered from one serotype become susceptible to the other serotype and can be reinfected. In this paper we analyze the model of dengue fever with two infections from the different serotype by linear analysis. Then we study the effect of vaccination to the model. In numerical simulation, we use Runge-Kutta order 4 to integrate the solution of the system.

  20. [Rhabdomyolysis associated with dengue fever in a lupic patient].

    PubMed

    Verdolin, Louise D; Borner, Alice R; Mussi, Henrique; Gismondi, Ronaldo A; Schau, Bruno; Ramos, Ricardo C

    2014-01-01

    This report describes the case of a woman with systemic lupus erythematous (SLE) that developed rhabdomyolysis after being infected by dengue virus. There are only a few cases of SLE accompanied by rhabdomyolysis, none of them associated with dengue fever. Initially, the woman presented high fever, myalgia, muscular weakness, mild headache, polyarthralgia and thrombocytopenia reminding a lupus flare, but since the number of people infected by dengue at that time was high and the symptoms from both conditions are similar, a dengue serology was requested. After a few days, the patient developed rhabdomyolysis. She was then submitted to immunosuppressive drugs, urinary alkalization and vigorous hydration, which improved her muscle damage and inflammatory condition. The positive dengue serology was only available after the therapy above had been established. She was discharged in an asymptomatic state. This case demonstrates how alike dengue fever and a lupus flare are, warning clinicians that, especially during an epidemic, both diseases should be carefully differentiated in order to establish a correct and efficient therapy. PMID:25627228

  1. The re-emergence of dengue in China.

    PubMed

    Ooi, Eng Eong

    2015-01-01

    The number of reports in the literature on dengue outbreaks in various parts of south China is increasing. This trend is likely contributed to by multiple factors, chief among which is the increase in trade and human movement in and out of China from the Southeast Asian region where dengue is firmly endemic. However, a holistic picture of dengue in China and how the public health authorities are responding to this global health challenge has been missing. In a research article published in BMC Medicine, Lai et al. have now filled this gap in knowledge by analysing statutorily mandated national dengue surveillance data from 1990 till 2014. They also conducted time series analyses to identify key drivers of dengue transmission in south China as well as from south China to the other parts of this vast and populous country. Their findings, as well as the description of surveillance and disease control activities in China, highlight urgent steps that need to be taken if China wishes to prevent itself from becoming another country that experiences large and frequent cycles of epidemic dengue. PMID:25925732

  2. Meteorological factors and dengue fever transmission in South Taiwan

    NASA Astrophysics Data System (ADS)

    Chien, Lung-Chang; Lin, Yuan-Chien; Cheng, Ming-Hung; Yu, Hwa-Lung

    2013-04-01

    The variations in meteorological conditions induced by climate change causes the diffusion pattern of infectious disease and serious epidemic situation. The objective of this study is to investigate the impact of meteorological variables to the temporal variation of dengue fever epidemic in weekly basis in south Taiwan. Several extreme and average index of meteorological variables, i.e. temperature and humidity, were used for this analysis, including averaged, maximum and minimum temperature, and average rainfall, maximum 1-hr rainfall, and maximum 24-hr rainfall. This study applies the distributed lag nonlinear model (DLNM) to reveal the significant meteorological variables and their temporal lag effects to the dengue fever epidemic by analyzing the dengue fever records from 1998-2011. Results show that the weekly minimum temperature (minT) and 1-hr maximum rainfall (maxR) are significantly important to the dengue fever spread. Among them, once minT is higher than 20°C, the relative risk of dengue fever of nine-fourteen week later will be significantly elevated. On the other hand, the incidences of maxR higher than 80mm can also increase the relative risk of dengue fever occurrences around nine-fourteen weeks afterwards.

  3. Susceptibility of mouse macrophage J774 to dengue virus infection.

    PubMed

    Moreno-Altamirano, María M B; Sánchez-García, F Javier; Legorreta-Herrera, Martha; Aguilar-Carmona, Israel

    2007-01-01

    The aim of this study was to investigate whether the J774 mouse macrophage cell line could be used as an in vitro model for dengue virus infection (DENV). After 3 days, infection in J774 cells was assessed by detecting dengue virus non-structural protein 1 (NSP-1) production either by dot blot or indirect immunofluorescence assay (IFA) of saponine-permeabilized J774 cells and then confirmed by RT-PCR (171 bp product, corresponding to the DENV-2 core). Based on the presence of NSP-1 in infected but not in non-infected cells by both IFA and dot blot, as well as the amplification of a 171-bp DENV-2-specific RT-PCR product exclusively in the infected cells, the J774 cell line was found to be permissive for dengue virus infection. As far as we know, this is the first report that the J774 mouse macrophage cell line is infected with dengue virus and, thus, that it can be used as an alternative in vitro model for dengue virus infection studies. This finding could help to further elucidate the mechanisms involved in dengue virus infection and pathogenesis. PMID:17356302

  4. Biochemical characterization of different genotypes of Paenibacillus larvae subsp. larvae, a honey bee bacterial pathogen.

    PubMed

    Neuendorf, Sandra; Hedtke, Kati; Tangen, Gerhard; Genersch, Elke

    2004-07-01

    Paenibacillus larvae subsp. larvae (P. l. larvae) is the aetiological agent of American foulbrood (AFB), the most virulent bacterial disease of honey bee brood worldwide. In many countries AFB is a notifiable disease since it is highly contagious, in most cases incurable and able to kill affected colonies. Genotyping of field isolates of P. l. larvae revealed at least four genotypes (AB, Ab, ab and alpha B) present in Germany which are genotypically different from the reference strain DSM 7030. Therefore, based on these data, five different genotypes of P. l. larvae are now identified with genotype AB standing out with a characteristic brown-orange and circled two-coloured colony morphology. Analysing the metabolic profiles of three German genotypes (AB, Ab and ab) as well as of the reference strain using the Biolog system, a characteristic biochemical fingerprint could be obtained for each strain. Cluster analysis showed that while genotypes Ab, ab and the reference strain DSM 7030 are rather similar, genotype AB is clearly different from the others. Analysis of all isolates for plasmid DNA revealed two different plasmids present only in isolates belonging to genotype AB. Therefore, genotype AB is remarkable in all aspects analysed so far. Future analysis will show whether or not these differences will expand to differences in virulence. PMID:15256579

  5. The Battle between Infection and Host Immune Responses of Dengue Virus and Its Implication in Dengue Disease Pathogenesis

    PubMed Central

    Sun, Peifang; Kochel, Tadeusz J.

    2013-01-01

    Dengue virus (DENV) is a mosquito-transmitted single stranded RNA virus belonging to genus Flavivirus. The virus is endemic in the tropical and subtropical countries of the world, causing diseases classified according to symptoms and severity (from mild to severe) as dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. Among a variety of human cell types targeted by DENV, monocytes, macrophages, and dendritic cells are members of innate immunity, capable of mounting rapid inflammatory responses. These cells are also major antigen presenting cells, responsible for activating the adaptive immunity for long-term memory. This paper is an overview of the current understanding of the following mutually affected aspects: DENV structure, viral infectivity, cellular receptors, innate immune response, and adaptive immunity. PMID:23476150

  6. Commercial dengue rapid diagnostic tests for point-of-care application: recent evaluations and future needs?

    PubMed

    Blacksell, Stuart D

    2012-01-01

    Dengue fever, dengue haemorrhagic fever, and dengue shock syndrome (DF/DHF/DSS) are tropical diseases that cause significant humanitarian and economic hardship. It is estimated that more than 2.5 billion people are at risk of infection and more than 100 countries have endemic dengue virus transmission. Laboratory tests are essential to provide an accurate diagnosis of dengue virus infection so that appropriate treatment and patient management may be administered. In many dengue endemic settings, laboratory diagnostic resources are limited and simple rapid diagnostic tests (RDTs) provide opportunities for point-of-care diagnosis. This paper addresses current issues relating to the application of commercial dengue RDTs for the diagnosis of acute dengue virus infection, recent diagnostic evaluations, and identifies future needs. PMID:22654479

  7. Early central nervous system involvement in a young patient with dengue encephalitis.

    PubMed

    Alice, V; Cheong, B M K

    2016-02-01

    A previously well 13-year-old boy presented with a short history of fever and altered mental status. His mother was admitted for dengue fever and there had been a recent dengue outbreak in their neighbourhood. He was diagnosed with dengue encephalitis as both his dengue non-structural protein 1 (NS-1) antigen and cerebrospinal fluid (CSF) dengue polymerase chain reaction (PCR) were positive. He did not have haemoconcentration, thrombocytopenia or any warning signs associated with severe dengue. He recovered fully with supportive treatment. This case highlights the importance of considering the diagnosis of dengue encephalitis in patients from dengue endemic areas presenting with an acute febrile illness and neurological symptoms. PMID:27130747

  8. Cytokine factors present in dengue patient sera induces alterations of junctional proteins in human endothelial cells.

    PubMed

    Appanna, Ramapraba; Wang, Seok Mui; Ponnampalavanar, Sasheela A; Lum, Lucy Chai See; Sekaran, Shamala Devi

    2012-11-01

    Plasma leakage in severe dengue has been postulated to be associated with skewed cytokine immune responses. In this study, the association of cytokines with vascular permeability in dengue patients was investigated. Human serum samples collected from 48 persons (13 with dengue fever, 29 with dengue hemorrhagic fever, and 6 healthy) were subjected to cytokines analysis by using Luminex Multiplex Technology. Selected serum samples from patients with dengue hemorrhagic fever sera and recombinant human cytokines were then tested for roles on inducing vascular permeability by treatment of human umbilical vein endothelial cells. Confocal immunofluorescence staining indicated morphologic alteration of human umbilical vein endothelial cells treated with serum samples from patients with dengue hemorrhagic fever compared with serum samples from healthy persons. The findings suggest that cytokines produced during dengue hemorrhagic infections could induce alterations in the vascular endothelium, which may play a fundamental role in the pathophysiology of dengue. PMID:22987650

  9. Community Involvement in Dengue Outbreak Control: An Integrated Rigorous Intervention Strategy

    PubMed Central

    Lin, Hualiang; Liu, Tao; Song, Tie; Lin, Lifeng; Xiao, Jianpeng; Lin, Jinyan; He, Jianfeng; Zhong, Haojie; Hu, Wenbiao; Deng, Aiping; Peng, Zhiqiang; Ma, Wenjun; Zhang, Yonghui

    2016-01-01

    Background An explosive outbreak of dengue fever occurred in Guangdong Province, China in 2014. A community-based integrated intervention was applied to control this outbreak in the capital city Guangzhou, where dengue epidemic was mainly caused by imported cases. Methodology/Principal Findings We used a time series generalized additive model based on meteorological factors to assess the effectiveness of this intervention. The results showed that there was significant reduction in mosquito density following the intervention, and there was a 70.47% (95% confidence interval: 66.07%, 74.88%) reduction in the reported dengue cases compared with the predicted cases after 12 days since the beginning of the intervention, we estimated that a total of 23,302 dengue cases were prevented. Conclusions This study suggests that an integrated dengue intervention program has significant effects to control a dengue outbreak in areas where dengue epidemic was mainly caused by imported dengue cases. PMID:27548481

  10. Evaluating probabilistic dengue risk forecasts from a prototype early warning system for Brazil.

    PubMed

    Lowe, Rachel; Coelho, Caio As; Barcellos, Christovam; Carvalho, Marilia Sá; Catão, Rafael De Castro; Coelho, Giovanini E; Ramalho, Walter Massa; Bailey, Trevor C; Stephenson, David B; Rodó, Xavier

    2016-01-01

    Recently, a prototype dengue early warning system was developed to produce probabilistic forecasts of dengue risk three months ahead of the 2014 World Cup in Brazil. Here, we evaluate the categorical dengue forecasts across all microregions in Brazil, using dengue cases reported in June 2014 to validate the model. We also compare the forecast model framework to a null model, based on seasonal averages of previously observed dengue incidence. When considering the ability of the two models to predict high dengue risk across Brazil, the forecast model produced more hits and fewer missed events than the null model, with a hit rate of 57% for the forecast model compared to 33% for the null model. This early warning model framework may be useful to public health services, not only ahead of mass gatherings, but also before the peak dengue season each year, to control potentially explosive dengue epidemics. PMID:26910315

  11. The live attenuated dengue vaccine TV003 elicits complete protection against dengue in a human challenge model.

    PubMed

    Kirkpatrick, Beth D; Whitehead, Stephen S; Pierce, Kristen K; Tibery, Cecilia M; Grier, Palmtama L; Hynes, Noreen A; Larsson, Catherine J; Sabundayo, Beulah P; Talaat, Kawsar R; Janiak, Anna; Carmolli, Marya P; Luke, Catherine J; Diehl, Sean A; Durbin, Anna P

    2016-03-16

    A dengue human challenge model can be an important tool to identify candidate dengue vaccines that should be further evaluated in large efficacy trials in endemic areas. Dengue is responsible for about 390 million infections annually. Protective efficacy results for the most advanced dengue vaccine candidate (CYD) were disappointing despite its ability to induce neutralizing antibodies against all four dengue virus (DENV) serotypes. TV003 is a live attenuated tetravalent DENV vaccine currently in phase 2 evaluation. To better assess the protective efficacy of TV003, a randomized double-blind, placebo-controlled trial in which recipients of TV003 or placebo were challenged 6 months later with a DENV-2 strain, rDEN2Δ30, was conducted. The primary endpoint of the trial was protection against dengue infection, defined as rDEN2Δ30 viremia. Secondary endpoints were protection against rash and neutropenia. All 21 recipients of TV003 who were challenged with rDEN2Δ30 were protected from infection with rDEN2Δ30. None developed viremia, rash, or neutropenia after challenge. In contrast, 100% of the 20 placebo recipients who were challenged with rDEN2Δ30 developed viremia, 80% developed rash, and 20% developed neutropenia. TV003 induced complete protection against challenge with rDEN2Δ30 administered 6 months after vaccination. TV003 will be further evaluated in dengue-endemic areas. The controlled dengue human challenge model can accelerate vaccine development by evaluating the protection afforded by the vaccine, thereby eliminating poor candidates from further consideration before the initiation of large efficacy trials. PMID:27089205

  12. Drosophila larvae: Thermal ecology in changing environments

    NASA Astrophysics Data System (ADS)

    Wang, George

    Temperature affects almost all aspects of life. Although much work has been done to assess the impact of temperature on organismal performance, relatively little is known about how organisms behaviorally regulate temperature, how these behaviors effect population fitness, or how changing climate may interact with these behaviors. I explore these questions with the model system Drosophila larvae. Larvae are small, with a low thermal mass and limited capacity for physiological thermoregulation. Mortality is generally high in larvae, with large potential impacts on population growth rate. Thus behavioral thermoregulation in larvae should be of critical selective importance. I present a review of the current knowledge of Drosophila thermal preference. I describe quantifiable thermoregulatory behaviors ( TMV and TW) unique to larvae. I show interspecific variation of these behaviors in Drosophila melanogaster and several close relatives, and intraspecific variation between populations collected from different environments. I also investigate these behaviors in two mutant lines, ssa and biz, to investigate the genetic basis of these behaviors. I show that larval thermoregulatory systems are independent of those of adults. Further these thermoregulatory behaviors differ between two sister species, D. yakuba and D. santomea. Although these two species readily hybridize in laboratory conditions, very few hybrids are observed in the field. The surprising result that hybrids of D. yakuba and D. santomea seem to inherit TMV from D. yakuba suggests a novel extrinsic isolation mechanism between the two species. I explore how fitness is the result of the interaction between genetics and the environment. I utilize Monte Carlo simulation to show how non-linear norms of reaction generate variation in populations even in the absence of behavior or epigenetic evolutionary mechanisms. Finally I investigate the global distribution of temperatures in which these organisms exist using

  13. Factors Affecting Dengue Prevention Practices: Nationwide Survey of the Malaysian Public

    PubMed Central

    Wong, Li Ping; Shakir, Sharina Mahavera Mohamad; Atefi, Narges; AbuBakar, Sazaly

    2015-01-01

    Background Efforts to stamp dengue in many dengue endemic countries has met little success. There is a need to re-examine and understand how the public at large view the dengue prevention efforts. This study aimed to examine the demographic factors, theoretical constructs of the Health Belief Model and knowledge about dengue and how these influence the practice of dengue prevention. Methods A national telephone survey was carried out with 2,512 individuals of the Malaysian public aged 18–60 years. Results The majority (73%) of the Malaysian public had a total dengue prevention score of 51–100 (of a possible score of 1–100). Multivariate analysis suggests significant correlates of higher dengue prevention practices with demographic background, perception of susceptibility to dengue, perceived density of mosquitoes in the neighbourhood and knowledge about dengue. Households of lower income of which the majority (40.7%) were from the rural areas, were associated with the highest odds [OR = 1.33; 95%CI = 1.09–1.67; p = 0.004] of dengue prevention. Dengue prevention practices were also less likely to be undertaken in neighbourhoods where the responders perceived there is no and/or low density of mosquitoes. Dengue prevention practices are also less likely to be practiced by skilled workers [OR = 0.78; 95%CI = 0.63–0.95; p = 0.029] compared to those unemployed. Higher perceived susceptibility to dengue was associated with higher dengue prevention practices and participants with higher dengue knowledge were found to have a higher level of involvement in dengue prevention practices. Conclusion Results from the study suggest that in formulating approaches to contain dengue, strategies should be developed to cultivate dengue prevention practices among urban population and target areas with low density of mosquitoes where public perceived a less likely chance of getting dengue. Dengue prevention campaigns should focus on messages highlighting the risk of contracting

  14. Requirements for in vitro germination of Paenibacillus larvae spores.

    PubMed

    Alvarado, Israel; Phui, Andy; Elekonich, Michelle M; Abel-Santos, Ernesto

    2013-03-01

    Paenibacillus larvae is the causative agent of American foulbrood (AFB), a disease affecting honey bee larvae. First- and second-instar larvae become infected when they ingest food contaminated with P. larvae spores. The spores then germinate into vegetative cells that proliferate in the midgut of the honey bee. Although AFB affects honey bees only in the larval stage, P. larvae spores can be distributed throughout the hive. Because spore germination is critical for AFB establishment, we analyzed the requirements for P. larvae spore germination in vitro. We found that P. larvae spores germinated only in response to l-tyrosine plus uric acid under physiologic pH and temperature conditions. This suggests that the simultaneous presence of these signals is necessary for spore germination in vivo. Furthermore, the germination profiles of environmentally derived spores were identical to those of spores from a biochemically typed strain. Because l-tyrosine and uric acid are the only required germinants in vitro, we screened amino acid and purine analogs for their ability to act as antagonists of P. larvae spore germination. Indole and phenol, the side chains of tyrosine and tryptophan, strongly inhibited P. larvae spore germination. Methylation of the N-1 (but not the C-3) position of indole eliminated its ability to inhibit germination. Identification of the activators and inhibitors of P. larvae spore germination provides a basis for developing new tools to control AFB. PMID:23264573

  15. Interactions among Drosophila larvae before and during collision.

    PubMed

    Otto, Nils; Risse, Benjamin; Berh, Dimitri; Bittern, Jonas; Jiang, Xiaoyi; Klämbt, Christian

    2016-01-01

    In populations of Drosophila larvae, both, an aggregation and a dispersal behavior can be observed. However, the mechanisms coordinating larval locomotion in respect to other animals, especially in close proximity and during/after physical contacts are currently only little understood. Here we test whether relevant information is perceived before or during larva-larva contacts, analyze its influence on behavior and ask whether larvae avoid or pursue collisions. Employing frustrated total internal reflection-based imaging (FIM) we first found that larvae visually detect other moving larvae in a narrow perceptive field and respond with characteristic escape reactions. To decipher larval locomotion not only before but also during the collision we utilized a two color FIM approach (FIM(2c)), which allowed to faithfully extract the posture and motion of colliding animals. We show that during collision, larval locomotion freezes and sensory information is sampled during a KISS phase (german: Kollisions Induziertes Stopp Syndrom or english: collision induced stop syndrome). Interestingly, larvae react differently to living, dead or artificial larvae, discriminate other Drosophila species and have an increased bending probability for a short period after the collision terminates. Thus, Drosophila larvae evolved means to specify behaviors in response to other larvae. PMID:27511760

  16. Interactions among Drosophila larvae before and during collision

    PubMed Central

    Otto, Nils; Risse, Benjamin; Berh, Dimitri; Bittern, Jonas; Jiang, Xiaoyi; Klämbt, Christian

    2016-01-01

    In populations of Drosophila larvae, both, an aggregation and a dispersal behavior can be observed. However, the mechanisms coordinating larval locomotion in respect to other animals, especially in close proximity and during/after physical contacts are currently only little understood. Here we test whether relevant information is perceived before or during larva-larva contacts, analyze its influence on behavior and ask whether larvae avoid or pursue collisions. Employing frustrated total internal reflection-based imaging (FIM) we first found that larvae visually detect other moving larvae in a narrow perceptive field and respond with characteristic escape reactions. To decipher larval locomotion not only before but also during the collision we utilized a two color FIM approach (FIM2c), which allowed to faithfully extract the posture and motion of colliding animals. We show that during collision, larval locomotion freezes and sensory information is sampled during a KISS phase (german: Kollisions Induziertes Stopp Syndrom or english: collision induced stop syndrome). Interestingly, larvae react differently to living, dead or artificial larvae, discriminate other Drosophila species and have an increased bending probability for a short period after the collision terminates. Thus, Drosophila larvae evolved means to specify behaviors in response to other larvae. PMID:27511760

  17. From trochophore to pilidium and back again - a larva's journey.

    PubMed

    Maslakova, Svetlana A; Hiebert, Terra C

    2014-01-01

    Nemerteans, a phylum of marine lophotrochozoan worms, have a biphasic life history with benthic adults and planktonic larvae. Nemertean larval development is traditionally categorized into direct and indirect. Indirect development via a long-lived planktotrophic pilidium larva is thought to have evolved in one clade of nemerteans, the Pilidiophora, from an ancestor with a uniformly ciliated planuliform larva. Planuliform larvae in a member of a basal nemertean group, the Palaeonemertea, have been previously shown to possess a vestigial prototroch, homologous to the primary larval ciliated band in the trochophores of other spiralian phyla, such as annelids and mollusks. We review literature on nemertean larval development, and include our own unpublished observations. We highlight recent discoveries of numerous pilidiophoran species with lecithotrophic larvae. Some of these larvae superficially resemble uniformly ciliated planuliform larvae of other nemerteans. Others possess one or two transverse ciliary bands, which superficially resemble the prototroch and telotroch of some spiralian trochophores. We also summarize accumulating evidence for planktotrophic feeding by larvae of the order Hoplonemertea, which until now were considered to be lecithotrophic. We suggest that 1) non-feeding pilidiophoran larval forms are derived from a feeding pilidium; 2) such forms have likely evolved many times independently within the Pilidiophora; 3) any resemblance of such larvae to the trochophores of other spiralians is a result of convergence and that 4) the possibility of planktotrophy in hoplonemertean larvae may influence estimates of pelagic larval duration, dispersal, and population connectivity in this group. PMID:25690972

  18. The Identification of Congeners and Aliens by Drosophila Larvae

    PubMed Central

    Del Pino, Francisco; Jara, Claudia; Pino, Luis; Medina-Muñoz, María Cristina; Alvarez, Eduardo; Godoy-Herrera, Raúl

    2015-01-01

    We investigated the role of Drosophila larva olfactory system in identification of congeners and aliens. We discuss the importance of these activities in larva navigation across substrates, and the implications for allocation of space and food among species of similar ecologies. Wild type larvae of cosmopolitan D. melanogaster and endemic D. pavani, which cohabit the same breeding sites, used species-specific volatiles to identify conspecifics and aliens moving toward larvae of their species. D. gaucha larvae, a sibling species of D. pavani that is ecologically isolated from D. melanogaster, did not respond to melanogaster odor cues. Similar to D. pavani larvae, the navigation of pavani female x gaucha male hybrids was influenced by conspecific and alien odors, whereas gaucha female x pavani male hybrid larvae exhibited behavior similar to the D. gaucha parent. The two sibling species exhibited substantial evolutionary divergence in processing the odor inputs necessary to identify conspecifics. Orco (Or83b) mutant larvae of D. melanogaster, which exhibit a loss of sense of smell, did not distinguish conspecific from alien larvae, instead moving across the substrate. Syn97CS and rut larvae of D. melanogaster, which are unable to learn but can smell, moved across the substrate as well. The Orco (Or83b), Syn97CS and rut loci are necessary to orient navigation by D. melanogaster larvae. Individuals of the Trana strain of D. melanogaster did not respond to conspecific and alien larval volatiles and therefore navigated randomly across the substrate. By contrast, larvae of the Til-Til strain used larval volatiles to orient their movement. Natural populations of D. melanogaster may exhibit differences in identification of conspecific and alien larvae. Larval locomotion was not affected by the volatiles. PMID:26313007

  19. The Identification of Congeners and Aliens by Drosophila Larvae.

    PubMed

    Del Pino, Francisco; Jara, Claudia; Pino, Luis; Medina-Muñoz, María Cristina; Alvarez, Eduardo; Godoy-Herrera, Raúl

    2015-01-01

    We investigated the role of Drosophila larva olfactory system in identification of congeners and aliens. We discuss the importance of these activities in larva navigation across substrates, and the implications for allocation of space and food among species of similar ecologies. Wild type larvae of cosmopolitan D. melanogaster and endemic D. pavani, which cohabit the same breeding sites, used species-specific volatiles to identify conspecifics and aliens moving toward larvae of their species. D. gaucha larvae, a sibling species of D. pavani that is ecologically isolated from D. melanogaster, did not respond to melanogaster odor cues. Similar to D. pavani larvae, the navigation of pavani female x gaucha male hybrids was influenced by conspecific and alien odors, whereas gaucha female x pavani male hybrid larvae exhibited behavior similar to the D. gaucha parent. The two sibling species exhibited substantial evolutionary divergence in processing the odor inputs necessary to identify conspecifics. Orco (Or83b) mutant larvae of D. melanogaster, which exhibit a loss of sense of smell, did not distinguish conspecific from alien larvae, instead moving across the substrate. Syn97CS and rut larvae of D. melanogaster, which are unable to learn but can smell, moved across the substrate as well. The Orco (Or83b), Syn97CS and rut loci are necessary to orient navigation by D. melanogaster larvae. Individuals of the Trana strain of D. melanogaster did not respond to conspecific and alien larval volatiles and therefore navigated randomly across the substrate. By contrast, larvae of the Til-Til strain used larval volatiles to orient their movement. Natural populations of D. melanogaster may exhibit differences in identification of conspecific and alien larvae. Larval locomotion was not affected by the volatiles. PMID:26313007

  20. Use of a Rapid Test for Diagnosis of Dengue during Suspected Dengue Outbreaks in Resource-Limited Regions.

    PubMed

    Hunsperger, Elizabeth A; Sharp, Tyler M; Lalita, Paul; Tikomaidraubuta, Kini; Cardoso, Yolanda Rebello; Naivalu, Taina; Khan, Aalisha Sahu; Marfel, Maria; Hancock, W Thane; Tomashek, Kay M; Margolis, Harold S

    2016-08-01

    Dengue is major public health problem, globally. Timely verification of suspected dengue outbreaks allows for public health response, leading to the initiation of appropriate clinical care. Because the clinical presentation of dengue is nonspecific, dengue diagnosis would benefit from a sensitive rapid diagnostic test (RDT). We evaluated the diagnostic performance of an RDT that detects dengue virus (DENV) nonstructural protein 1 (NS1) and anti-DENV IgM during suspected acute febrile illness (AFI) outbreaks in four countries. Real-time reverse transcription-PCR and anti-DENV IgM enzyme-linked immunosorbent assay were used to verify RDT results. Anti-DENV IgM RDT sensitivity and specificity ranged from 55.3 to 91.7% and 85.3 to 98.5%, respectively, and NS1 sensitivity and specificity ranged from 49.7 to 92.9% and 22.2 to 89.0%, respectively. Sensitivity varied by timing of specimen collection and DENV serotype. Combined test results moderately improved the sensitivity. The use of RDTs identified dengue as the cause of AFI outbreaks where reference diagnostic testing was limited or unavailable. PMID:27225409

  1. Vascular Leakage in Dengue Hemorrhagic Fever Is Associated with Dengue Infected Monocytes, Monocyte Activation/Exhaustion, and Cytokines Production

    PubMed Central

    Chunhakan, Sirichan; Butthep, Punnee; Yoksan, Sutee; Tangnararatchakit, Kanchana; Chuansumrit, Ampaiwan

    2015-01-01

    The vascular leakage was shown by the increment of hematocrit (Hct), dengue viral infected monocyte, monocyte status, and cytokines production in patients infected with dengue virus. Dengue viral antigens were demonstrated in monocytes (CD14+) from peripheral blood mononuclear cells. The increased levels of Hct, interleukin- (IL-) 10, and tumor necrosis factor-alpha (TNF-α) were detected in dengue fever (DF), dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) patients as compared with other febrile illnesses (OFIs). The highest levels of Hct and IL-10 were detected in DSS patients as compared with other groups (P < 0.05) especially on one day before and after defervescence. The unstimulated and lipopolysaccharide- (LPS-) stimulated monocytes from DSS patients showed the significantly decreased of intracellular IL-1β and TNF-α. In addition, the lowest level of mean fluorescence intensity (MFI) of CD11b expression on monocytes surface in DSS patients was also demonstrated. Furthermore, the negative correlations between IL-10 levels and intracellular IL-1β and MFI of CD11b expression in unstimulated and LPS-stimulated monocytes were also detected. Nevertheless, not only were the relationships between the prominent IL-10 and the suppression of intracellular monocyte secretion, namely, IL-1β, TNF-α, demonstrated but also the effect of vascular leakage was observed. PMID:25722892

  2. Co-occurrence Patterns of the Dengue Vector Aedes aegypti and Aedes mediovitattus, a Dengue Competent Mosquito in Puerto Rico

    PubMed Central

    Little, Eliza; Barrera, Roberto; Seto, Karen C.; Diuk-Wasser, Maria

    2015-01-01

    Aedes aegypti is implicated in dengue transmission in tropical and subtropical urban areas around the world. Ae. aegypti populations are controlled through integrative vector management. However, the efficacy of vector control may be undermined by the presence of alternative, competent species. In Puerto Rico, a native mosquito, Ae. mediovittatus, is a competent dengue vector in laboratory settings and spatially overlaps with Ae. aegypti. It has been proposed that Ae. mediovittatus may act as a dengue reservoir during inter-epidemic periods, perpetuating endemic dengue transmission in rural Puerto Rico. Dengue transmission dynamics may therefore be influenced by the spatial overlap of Ae. mediovittatus, Ae. aegypti, dengue viruses, and humans. We take a landscape epidemiology approach to examine the association between landscape composition and configuration and the distribution of each of these Aedes species and their co-occurrence. We used remotely sensed imagery from a newly launched satellite to map landscape features at very high spatial resolution. We found that the distribution of Ae. aegypti is positively predicted by urban density and by the number of tree patches, Ae. mediovittatus is positively predicted by the number of tree patches, but negatively predicted by large contiguous urban areas, and both species are predicted by urban density and the number of tree patches. This analysis provides evidence that landscape composition and configuration is a surrogate for mosquito community composition, and suggests that mapping landscape structure can be used to inform vector control efforts as well as to inform urban planning. PMID:21989642

  3. Two Case Reports on Thalamic and Basal Ganglia Involvement in Children with Dengue Fever

    PubMed Central

    Adhikari, Lihini; Wijesekera, Saraji; Wijayawardena, Maheshaka; Chandrasiri, Suchithra

    2016-01-01

    There have been increasing numbers of case reports of dengue infection with unusual manifestations. Such unusual manifestations including acute liver failure and encephalopathy could be manifested even in the absence of significant plasma leakage. Further, severe organ involvement including nervous system involvement indicates severe dengue infection. However, neurological manifestations of dengue fever are rare. This is the first case report of dengue infection with thalamic and basal ganglia involvement in Sri Lanka. PMID:27478661

  4. Two Case Reports on Thalamic and Basal Ganglia Involvement in Children with Dengue Fever.

    PubMed

    Liyanage, Guwani; Adhikari, Lihini; Wijesekera, Saraji; Wijayawardena, Maheshaka; Chandrasiri, Suchithra

    2016-01-01

    There have been increasing numbers of case reports of dengue infection with unusual manifestations. Such unusual manifestations including acute liver failure and encephalopathy could be manifested even in the absence of significant plasma leakage. Further, severe organ involvement including nervous system involvement indicates severe dengue infection. However, neurological manifestations of dengue fever are rare. This is the first case report of dengue infection with thalamic and basal ganglia involvement in Sri Lanka. PMID:27478661

  5. Essential oils from Zanthoxylum fagara Wild Lime, Ruta chalepensis L. and Thymus vulgaris L.: Composition and activity against Aedes aegypti larvae.

    PubMed

    Pérez López, Luis Alejandro; de la Torre, Yael C; Cirio, Anabel Torres; de Torres, Noemí Waksman; Flores Suárez, Adriana Elizabeth; Aranda, Ricardo Salazar

    2015-09-01

    The dengue virus is transmitted by Aedes aegypti. Several plants are used to control this mosquito. In the present study the chemical composition of the essential oils of Ruta chalepensis, Zanthoxylum fagara and Thymus vulgaris were analyzed, and their activities against larvae of two A. aegypti populations were evaluated. The major compounds found in T. vulgaris were thymol and -cymene at 39.8% and 30.5%, respectively, with the major components being oxygenated monoterpenes and monoterpene hydrocarbons at 55.5% and 40.4%, respectively. For Z. fagara, the major compounds were sylvestrene and E-caryophyllene at 25.3% and 23.6%, respectively, with the major components being sesquiterpene and monoterpene hydrocarbons at 51.1% and 37.5%, respectively. Ketones were the predominant group of compounds found in R. chalepensis, with the major components being 2-undecanone and 2-nonanona at 43.7% and 35.4%, respectively. Essential oils from T. vulgaris, Z. fagara and R. chalepensis showed activity against larvae of the A. aegypti New Orleans strain, producing median lethal concentrations (LC₅₀) of 2.14, 27.57 and 2.69 g/mL, respectively, at 24 h. LC₅₀ values produced against larvae of a local A. aegypti population in Nuevo Leon, México, were 25.37, 60.42 and 20.13 g/mL, respectively, at 24 h. PMID:26525020

  6. Transcriptional response of honey bee larvae infected with the bacterial pathogen Paenibacillus larvae.

    PubMed

    Cornman, Robert Scott; Lopez, Dawn; Evans, Jay D

    2013-01-01

    American foulbrood disease of honey bees is caused by the bacterium Paenibacillus larvae. Infection occurs per os in larvae and systemic infection requires a breaching of the host peritrophic matrix and midgut epithelium. Genetic variation exists for both bacterial virulence and host resistance, and a general immunity is achieved by larvae as they age, the basis of which has not been identified. To quickly identify a pool of candidate genes responsive to P. larvae infection, we sequenced transcripts from larvae inoculated with P. larvae at 12 hours post-emergence and incubated for 72 hours, and compared expression levels to a control cohort. We identified 75 genes with significantly higher expression and six genes with significantly lower expression. In addition to several antimicrobial peptides, two genes encoding peritrophic-matrix domains were also up-regulated. Extracellular matrix proteins, proteases/protease inhibitors, and members of the Osiris gene family were prevalent among differentially regulated genes. However, analysis of Drosophila homologs of differentially expressed genes revealed spatial and temporal patterns consistent with developmental asynchrony as a likely confounder of our results. We therefore used qPCR to measure the consistency of gene expression changes for a subset of differentially expressed genes. A replicate experiment sampled at both 48 and 72 hours post infection allowed further discrimination of genes likely to be involved in host response. The consistently responsive genes in our test set included a hymenopteran-specific protein tyrosine kinase, a hymenopteran specific serine endopeptidase, a cytochrome P450 (CYP9Q1), and a homolog of trynity, a zona pellucida domain protein. Of the known honey bee antimicrobial peptides, apidaecin was responsive at both time-points studied whereas hymenoptaecin was more consistent in its level of change between biological replicates and had the greatest increase in expression by RNA-seq analysis

  7. Larvicidal efficacy screening of Anacardaciae crude extracts on the dengue hemorrhagic vector, Aedes aegypti.

    PubMed

    Zuharah, W F; Fadzly, N; Ali, Y; Zakaria, R; Juperi, S; Asyraf, M; Dieng, H

    2014-06-01

    Vector-borne diseases are still rife because of the re-emergence of diseases transmitted by mosquitoes. The objective of this paper is to evaluate the larvicidal efficacy of crude leaf extract of Mangifera indica, Gluta renghas, and Melanochyla fasciculiflora against vector of dengue hemorrhagic fever, Aedes aegypti. These plant species are endemic species and widely distributed in Malaysian forests. Leaves of Ma. indica, G. renghas and M. fascculiflora were collected from Teluk Bahang National Park, Penang Malaysia. Fractions of leaves were segregated, air-dried, powdered and extracted using Soxhlet with methanol. The solvent was removed by using rotary evaporator to obtain the crude extract. Using WHO standard larval bioassay test method, third instar larvae of Aedes aegypti were exposed to concentration ranging from 200- 4500 ppm of methanol extract for all plant species. Larval mortality was observed after 24 hours exposure. The highest susceptibility and toxicity was recorded by Mangifera indica with the lowest concentration at 800 ppm followed by M. fasciculiflora and G. renghas. This indicates that crude plant extract is very effective in killing Ae. aegypti mosquitoes. This finding may lead to new low cost alternative, environmentally friendly method for mosquito control programs. To our knowledge, this is the first report on larvicidal bioefficacy from endemic Malaysian plants. PMID:25134898

  8. Economic and Disease Burden of Dengue in Mexico

    PubMed Central

    Undurraga, Eduardo A.; Betancourt-Cravioto, Miguel; Ramos-Castañeda, José; Martínez-Vega, Ruth; Méndez-Galván, Jorge; Gubler, Duane J.; Guzmán, María G.; Halstead, Scott B.; Harris, Eva; Kuri-Morales, Pablo; Tapia-Conyer, Roberto; Shepard, Donald S.

    2015-01-01

    Background Dengue imposes a substantial economic and disease burden in most tropical and subtropical countries. Dengue incidence and severity have dramatically increased in Mexico during the past decades. Having objective and comparable estimates of the economic burden of dengue is essential to inform health policy, increase disease awareness, and assess the impact of dengue prevention and control technologies. Methods and Findings We estimated the annual economic and disease burden of dengue in Mexico for the years 2010–2011. We merged multiple data sources, including a prospective cohort study; patient interviews and macro-costing from major hospitals; surveillance, budget, and health data from the Ministry of Health; WHO cost estimates; and available literature. We conducted a probabilistic sensitivity analysis using Monte Carlo simulations to derive 95% certainty levels (CL) for our estimates. Results suggest that Mexico had about 139,000 (95%CL: 128,000–253,000) symptomatic and 119 (95%CL: 75–171) fatal dengue episodes annually on average (2010–2011), compared to an average of 30,941 symptomatic and 59 fatal dengue episodes reported. The annual cost, including surveillance and vector control, was US$170 (95%CL: 151–292) million, or $1.56 (95%CL: 1.38–2.68) per capita, comparable to other countries in the region. Of this, $87 (95%CL: 87–209) million or $0.80 per capita (95%CL: 0.62–1.12) corresponds to illness. Annual disease burden averaged 65 (95%CL: 36–99) disability-adjusted life years (DALYs) per million population. Inclusion of long-term sequelae, co-morbidities, impact on tourism, and health system disruption during outbreaks would further increase estimated economic and disease burden. Conclusion With this study, Mexico joins Panama, Puerto Rico, Nicaragua, and Thailand as the only countries or areas worldwide with comprehensive (illness and preventive) empirical estimates of dengue burden. Burden varies annually; during an outbreak

  9. Meta-Analysis of Dengue Severity during Infection by Different Dengue Virus Serotypes in Primary and Secondary Infections

    PubMed Central

    Khalid, Bahariah; Ching, Siew-Mooi; Chee, Hui-Yee

    2016-01-01

    Introduction Dengue virus (DENV) infection is currently a major cause of morbidity and mortality in the world; it has become more common and virulent over the past half-century and has gained much attention. Thus, this review compared the percentage of severe cases of both primary and secondary infections with different serotypes of dengue virus. Methods Data related to the number of cases involving dengue fever (DF), dengue hemorrhagic fever (DHF), dengue shock syndrome (DSS) or severe dengue infections caused by different serotypes of dengue virus were obtained by using the SCOPUS, the PUBMED and the OVID search engines with the keywords “(dengue* OR dengue virus*) AND (severe dengue* OR severity of illness index* OR severity* OR DF* OR DHF* OR DSS*) AND (serotypes* OR serogroup*)”, according to the MESH terms suggested by PUBMED and OVID. Results Approximately 31 studies encompassing 15,741 cases reporting on the dengue serotypes together with their severity were obtained, and meta-analysis was carried out to analyze the data. This study found that DENV-3 from the Southeast Asia (SEA) region displayed the greatest percentage of severe cases in primary infection (95% confidence interval (CI), 31.22–53.67, 9 studies, n = 598, I2 = 71.53%), whereas DENV-2, DENV-3, and DENV-4 from the SEA region, as well as DENV-2 and DENV-3 from non-SEA regions, exhibited the greatest percentage of severe cases in secondary infection (95% CI, 11.64–80.89, 4–14 studies, n = 668–3,149, I2 = 14.77–96.20%). Moreover, DENV-2 and DENV-4 from the SEA region had been found to be more highly associated with dengue shock syndrome (DSS) (95% CI, 10.47–40.24, 5–8 studies, n = 642–2,530, I2 = 76.93–97.70%), while DENV-3 and DENV-4 from the SEA region were found to be more highly associated with dengue hemorrhagic fever (DHF) (95% CI, 31.86–54.58, 9 studies, n = 674–2,278, I2 = 55.74–88.47%), according to the 1997 WHO dengue classification. Finally, DENV-2 and DENV-4

  10. Human to Mosquito Transmission of Dengue Viruses

    PubMed Central

    Carrington, Lauren B.; Simmons, Cameron P.

    2014-01-01

    The successful transmission of dengue virus from a human host to a mosquito vector requires a complex set of factors to align. It is becoming increasingly important to improve our understanding of the parameters that shape the human to mosquito component of the transmission cycle so that vaccines and therapeutic antivirals can be fully evaluated and epidemiological models refined. Here we describe these factors, and discuss the biological and environmental impacts and demographic changes that are influencing these dynamics. Specifically, we examine features of the human infection required for the mosquito to acquire the virus via natural blood feeding, as well as the biological and environmental factors that influence a mosquito’s susceptibility to infection, up to the point that they are capable of transmitting the virus to a new host. PMID:24987394

  11. Dengue — Quo tu et quo vadis?

    PubMed Central

    Chen, Rubing; Vasilakis, Nikos

    2011-01-01

    Dengue viruses (DENV) are by far the most important arboviral pathogens in the tropics around the world, putting at risk of infection nearly a third of the global human population. DENV are members of the genus Flavivirus in the Family Flaviviridae and comprise four antigenically distinct serotypes (DENV-1-4). Although they share almost identical epidemiological features, they are genetically distinct. Phylogenetic analyses have revealed valuable insights into the origins, epidemiology and the forces that shape DENV evolution in nature. In this review, we examine the current status of DENV evolution, including but not limited to rates of evolution, selection pressures, population sizes and evolutionary constraints, and we discuss how these factors influence transmission, pathogenesis and emergence. PMID:21994796

  12. Disruption of dengue virus transmission by mosquitoes

    PubMed Central

    Franz, Alexander W.E.; Balaraman, Velmurugan; Fraser, Malcolm J.

    2015-01-01

    Current control efforts for mosquito-borne arboviruses focus on mosquito control involving insecticide applications, which are becoming increasingly ineffective and unsustainable in urban areas. Mosquito population replacement is an alternative arbovirus control concept aiming at replacing virus-competent vector populations with laboratory-engineered incompetent vectors. A prerequisite for this strategy is the design of robust anti-pathogen effectors that can ultimately be genetically driven through a wild-type population. Several anti-pathogen effector concepts have been developed that target the RNA genomes of arboviruses such as dengue virus in a highly sequence-specific manner. Design principles are based on long inverted-repeat RNA triggered RNA interference, catalytic hammerhead ribozymes, and trans-splicing Group I Introns that are able to induce apoptosis in virus-infected cells following splicing with target viral RNA. PMID:26120563

  13. Immunopathogenesis Versus Protection in Dengue Virus Infections

    PubMed Central

    Rothman, Alan L.; Medin, Carey L.; Friberg, Heather; Currier, Jeffrey R.

    2014-01-01

    Dengue viruses (DENV) are mosquito-borne viruses that cause significant morbidity. The existence of four serotypes of DENV with partial immunologic cross-reactivity creates the opportunity for individuals to experience multiple acute DENV infections over the course of their lifetimes. Research over the past several years has revealed complex interactions between DENV and the human innate and adaptive immune systems that can have either beneficial or detrimental influences on the outcome of infection. Further studies that seek to distinguish protective from pathological immune responses in the context of natural DENV infection as well as clinical trials of candidate DENV vaccines have an important place in efforts to control the global impact of this re-emerging viral disease. PMID:24883262

  14. Immunopathogenesis Versus Protection in Dengue Virus Infections.

    PubMed

    Rothman, Alan L; Medin, Carey L; Friberg, Heather; Currier, Jeffrey R

    2014-03-01

    Dengue viruses (DENV) are mosquito-borne viruses that cause significant morbidity. The existence of four serotypes of DENV with partial immunologic cross-reactivity creates the opportunity for individuals to experience multiple acute DENV infections over the course of their lifetimes. Research over the past several years has revealed complex interactions between DENV and the human innate and adaptive immune systems that can have either beneficial or detrimental influences on the outcome of infection. Further studies that seek to distinguish protective from pathological immune responses in the context of natural DENV infection as well as clinical trials of candidate DENV vaccines have an important place in efforts to control the global impact of this re-emerging viral disease. PMID:24883262

  15. An outbreak of dengue fever in St. Croix (U. S. Virgin Islands), 2005.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the summer of 2005, an outbreak of dengue virus serotype-2 with cases of dengue hemorrhagic fever (DHF) occurred in St. Croix, US Virgin Islands. The medical records of all dengue laboratory-positive patients either seen in the Emergency Department of or admitted to the Governor Juan F. Luis Hosp...

  16. 78 FR 16505 - Prospective Grant of Exclusive License: Chimeric West Nile/Dengue Viruses

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-15

    ...: Chimeric West Nile/Dengue Viruses AGENCY: Centers for Disease Control and Prevention (CDC), Department of... license, in the field of use of in vitro diagnostics for dengue virus infection, to practice the... Application 61/049,342, filed 4/30/2008, entitled ``Engineered, Chimeric West Nile/Dengue Viruses;''...

  17. Co-circulation of Dengue and Chikungunya Viruses, Al Hudaydah, Yemen, 2012.

    PubMed

    Rezza, Giovanni; El-Sawaf, Gamal; Faggioni, Giovanni; Vescio, Fenicia; Al Ameri, Ranya; De Santis, Riccardo; Helaly, Ghada; Pomponi, Alice; Metwally, Dalia; Fantini, Massimo; Qadi, Hussein; Ciccozzi, Massimo; Lista, Florigio

    2014-08-01

    We investigated 400 cases of dengue-like illness in persons hospitalized during an outbreak in Al Hudaydah, Yemen, in 2012. Overall, 116 dengue and 49 chikungunya cases were diagnosed. Dengue virus type 2 was the predominant serotype. The co-circulation of these viruses indicates that mosquitoborne infections represent a public health threat in Yemen. PMID:25061762

  18. Complete Genome Sequencing of Dengue Virus Type I from Zhuhai City, China.

    PubMed

    Chen, Chao; Wei, Quande

    2016-01-01

    The detection and successful typing of dengue virus (DENV) from patients with suspected dengue fever are important for stopping outbreaks and preventing the recurrence of this virus. In this study, we reported complete genomic sequences of DENV-1 isolated from Zhuhai patients, providing basic information for future epidemic dengue disease detection. PMID:26868388

  19. An estimate of the global health care and lost productivity costs of dengue.

    PubMed

    Selck, Frederic W; Adalja, Amesh A; Boddie, Crystal R

    2014-11-01

    Contemporary cost estimates of dengue fever are difficult to attain in many countries in which the disease is endemic. By applying publicly available health care costs and wage data to recently available country-level estimates of dengue incidence, we estimate the total cost of dengue to be nearly 40 billion dollars in 2011. PMID:25409275

  20. Synthesis and characterization of silver nanoparticles using Gmelina asiatica leaf extract against filariasis, dengue, and malaria vector mosquitoes.

    PubMed

    Muthukumaran, Udaiyan; Govindarajan, Marimuthu; Rajeswary, Mohan; Hoti, S L

    2015-05-01

    Mosquitoes are blood-feeding insects and serve as the most important vectors for spreading human diseases such as malaria, yellow fever, dengue fever, and filariasis. The continued use of synthetic insecticides has resulted in resistance in mosquitoes. Synthetic insecticides are toxic and affect the environment by contaminating soil, water, and air, and then natural products may be an alternative to synthetic insecticides because they are effective, biodegradable, eco-friendly, and safe to environment. Botanical origin may serve as suitable alternative biocontrol techniques in the future. The present study was carried out to establish the larvicidal potential of leaf extracts of Gmelina asiatica and synthesized silver nanoparticles using aqueous leaf extract against late third instar larvae of Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. Larvae were exposed to varying concentrations of plant extracts and synthesized AgNPs for 24 h. The results were recorded from UV-visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy analysis support the biosynthesis and characterization of AgNPs. The maximum efficacy was observed in synthesized AgNPs against the larvae of An. stephensi (lethal dose (LC₅₀) = 22.44 μg/mL; LC₉₀ 40.65 μg/mL), Ae. aegypti (LC₅₀ = 25.77 μg/mL; LC₉₀ 45.98 μg/mL), and C. quinquefasciatus (LC₅₀ = 27.83 μg/mL; LC₉₀ 48.92 μg/mL), respectively. No mortality was observed in the control. This is the first report on mosquito larvicidal activity of plant-synthesized nanoparticles. Thus, the use of G. asiatica to synthesize silver nanoparticles is a rapid, eco-friendly, and a single-step approach and the AgNps formed can be potential mosquito larvicidal agents. PMID:25666372