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Sample records for large rift valley

  1. Rift Valley Fever Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV) is a mosquito-transmitted virus or arbovirus that is endemic in sub-Saharan Africa. In the last decade, Rift Valley fever (RVF) outbreaks have resulted in loss of human and animal life, as well as had significant economic impact. The disease in livestock is primarily a...

  2. Rift Valley Fever (RVF)

    MedlinePlus

    ... Outbreak resources, VHF information for specific groups, virus ecology, references... RVF Distribution Map Rift Valley Fever Transmission ... Outbreaks Outbreak Summaries RVF Distribution Map Resources Virus Ecology File Formats Help: How do I view different ...

  3. Rift Valley Fever Review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a disease of animals and humans that occurs in Africa and the Arabian Peninsula. A Phlebovirus in the family Bunyaviridae causes the disease that is transmitted by mosquitoes. Epidemics occur during years of unusually heavy rainfall that assessment models are being develo...

  4. East African Rift Valley, Kenya

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This rare, cloud free view of the East African Rift Valley, Kenya (1.5N, 35.5E) shows a clear view of the Turkwell River Valley, an offshoot of the African REift System. The East African Rift is part of a vast plate fracture which extends from southern Turkey, through the Red Sea, East Africa and into Mozambique. Dark green patches of forests are seen along the rift margin and tea plantations occupy the cooler higher ground.

  5. SATELLITE-BASED RIFT VALLEY FEVER FORECASTS PREDICT A LARGE YELLOW FEVER EPIDEMIC IN SUDAN, 2005

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustained, heavy East African rainfall is associated with Aedes spp. breeding in Kenyan grasslands and Rift Valley Fever (RVF) epidemics. Validated RVF forecasts use satellite measurements of vegetation greenness (which increases after heavy rains) and other eco-climate indicators. These models may ...

  6. Remote Sensing Contributions to Prediction and Risk Assessment of Natural Disasters Caused by Large Scale Rift Valley Fever Outbreaks

    NASA Technical Reports Server (NTRS)

    Anyamba, Assaf; Linthicum, Kenneth J.; Small, Jennifer; Britch, S. C.; Tucker, C. J.

    2012-01-01

    Remotely sensed vegetation measurements for the last 30 years combined with other climate data sets such as rainfall and sea surface temperatures have come to play an important role in the study of the ecology of arthropod-borne diseases. We show that epidemics and epizootics of previously unpredictable Rift Valley fever are directly influenced by large scale flooding associated with the El Ni o/Southern Oscillation. This flooding affects the ecology of disease transmitting arthropod vectors through vegetation development and other bioclimatic factors. This information is now utilized to monitor, model, and map areas of potential Rift Valley fever outbreaks and is used as an early warning system for risk reduction of outbreaks to human and animal health, trade, and associated economic impacts. The continuation of such satellite measurements is critical to anticipating, preventing, and managing disease epidemics and epizootics and other climate-related disasters.

  7. Large mammals from the Upper Neopleistocene reference sections in the Tunka rift valley, southwestern Baikal Region

    NASA Astrophysics Data System (ADS)

    Shchetnikov, A. A.; Klementiev, A. M.; Filinov, I. A.; Semeney, E. Yu.

    2015-03-01

    This work presents the data on new finds of fossil macrotheriofauna in the reference sections of the Upper Neopleistocene sediments in the Tunka rift valley (southwestern Baikal Region). The osteological material of a number of Late Neopleistocene mammals including extinct species rare for the Baikal region such as Crocuta spelaea, Panthera spelaea, and Spirocerus kiakhtensis (?) was directly dated with a radiocarbon (AMS) method. The obtained 14C data (18000-35000 years) allow one to rejuvenate significantly the upper limit of the common age interval of habitat of these animals in southern part of Eastern Siberia. Cave hyena and spiral-horned antelope lived in the Tunka rift valley in the Baikal region in Late Kargino time (37-24 ka), and cave lion survived the maximum in the Sartan cryochron in the region (21-20 ka). The study of collected paleontological collections provides a basis for selection of independent Kargino (MIS 3) faunal assemblages to use them for regional biostratigraphic analysis of Pleistocene deposits. Radiocarbon age dating of samples allows one to attribute confidently all paleofaunal remains available to the second half of the Late Pleistocene.

  8. Classification of the rift zones of venus: Rift valleys and graben belts

    NASA Astrophysics Data System (ADS)

    Guseva, E. N.

    2016-05-01

    The spatial distribution of rift zones of Venus, their topographic configuration, morphometric parameters, and the type of volcanism associating with rifts were analyzed. This allowed the main characteristic features of rifts to be revealed and two different types of rift-forming structures, serving for classification of rift zones as rift valleys and graben belts, to be isolated. These structural types (facies) of rift zones are differently expressed in the relief: rift valleys are individual deep (several kilometers) W-shaped canyons, while graben belts are clusters of multiple V-shaped and rather shallow (hundreds of meters) depressions. Graben belts are longer and wider, as compared to rift valleys. Rift valleys are spatially associated with dome-shaped volcanic rises and large volcanos (concentrated volcanic sources), while graben belts do not exhibit such associations. Volcanic activity in the graben belts are presented by spacious lava fields with no apparent sources of volcanism. Graben belts and rift valleys were formed during the Atlian Period of geologic history of Venus, and they characterized the tectonic style of the planet at the late stages of its geologic evolution. Formation of this or that structural facies of the rift zones of Venus were probably governed by the thickness of the lithosphere, its rheological properties, and the development degree of the mantle diapirs associating with rift zones.

  9. Remote Sensing Contributions to Prediction and Risk Assessment of Natural Diasters Caused by Large Scale Rift Valley fever Outbreaks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Remotely sensed vegetation measurements for the last 30 years combined with other climate data sets such as rainfall and sea surface temperatures have come to play an important role in the study of the ecology of vector-borne diseases. We show that episodic outbreaks of Rift Valley fever are influen...

  10. Rainfall and epizootic Rift Valley fever*

    PubMed Central

    Davies, F. G.; Linthicum, K. J.; James, A. D.

    1985-01-01

    Epizootic Rift Valley fever (RVF) has occurred in Kenya four times over the last 30 years. Widespread, frequent, and persistent rainfall has been a feature of these epizootic periods. A composite statistic, based upon measurements of these rainfall characteristics, is positive during periods of epizootic Rift Valley fever. The heavy rainfall raises the level of the water table in certain areas, flooding the grassland depressions (dambos) that are the habitat of the immature forms of certain ground-pool-breeding mosquitos of the genus Aedes. RVF virus is probably transmitted transovarially in these species, very large numbers of which emerge under these damp conditions. This is when clinical signs of the disease are first seen. PMID:3879206

  11. Detection and Response for Rift Valley fever

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever is a viral disease that impacts domestic livestock and humans in Africa and the Middle East, and poses a threat to military operations in these areas. We describe a Rift Valley fever Risk Monitoring website, and its ability to predict risk of disease temporally and spatially. We al...

  12. Diagnostic approaches for Rift Valley Fever

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Disease outbreaks caused by arthropod-borne animal viruses (arboviruses) resulting in significant livestock and economic losses world-wide appear to be increasing. Rift Valley fever (RVF) virus (RVFV) is an important arbovirus that causes lethal disease in cattle, camels, sheep and goats in Sub-Saha...

  13. Prediction of a Rift Valley fever Outbreak

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using satellite measurements to detect elevated sea surface temperatures (SSTs) and subsequent elevated normalized difference vegetation index (NDVI) data in Africa, we predicted an outbreak of Rift Valley fever (RVF) in humans and animals in the Horn of Africa during September 2006-May 2007. We det...

  14. Rift Valley fever: A neglected zoonotic disease?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a serious viral disease of animals and humans in Africa and the Middle East that is transmitted by mosquitoes. First isolated in Kenya during an outbreak in 1930, subsequent outbreaks have had a significant impact on animal and human health, as well as national economies. ...

  15. Forecast and Outbreak of Rift valley fever in Sudan, 2007

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background Rift Valley fever (RVF) outbreaks occur during heavy rainfall in various sub-Saharan countries including Kenya, Somalia, and Tanzania and more recently in Saudi Arabia and Yemen. Given the wide geographic and ecological range of RVF virus, it is necessary to monitor large areas for condit...

  16. Sociocultural and Economic Dimensions of Rift Valley Fever

    PubMed Central

    Muga, Geoffrey Otieno; Onyango-Ouma, Washington; Sang, Rosemary; Affognon, Hippolyte

    2015-01-01

    Health researchers have advocated for a cross-disciplinary approach to the study and prevention of infectious zoonotic diseases, such as Rift Valley Fever. It is believed that this approach can help bring out the social determinants and effects of the zoonotic diseases for the design of appropriate interventions and public health policy. A comprehensive literature review using a systematic search strategy was undertaken to explore the sociocultural and economic factors that influence the transmission and spread of Rift Valley Fever. Although the findings reveal a paucity of social research on Rift Valley Fever, they suggest that livestock sacrificial rituals, food preparation and consumption practices, gender roles, and inadequate resource base for public institutions are the key factors that influence the transmission. It is concluded that there is need for cross-disciplinary studies to increase the understanding of Rift Valley Fever and facilitate appropriate and timely response and mitigation measures. PMID:25688166

  17. Multiple Virus Lineages Sharing Recent Common Ancestry Were Associated with a Large Rift Valley Fever Outbreak among Livestock in Kenya during 2006-2007▿ †

    PubMed Central

    Bird, Brian H.; Githinji, Jane W. K.; Macharia, Joseph M.; Kasiiti, Jacqueline L.; Muriithi, Rees M.; Gacheru, Stephen G.; Musaa, Joseph O.; Towner, Jonathan S.; Reeder, Serena A.; Oliver, Jennifer B.; Stevens, Thomas L.; Erickson, Bobbie R.; Morgan, Laura T.; Khristova, Marina L.; Hartman, Amy L.; Comer, James A.; Rollin, Pierre E.; Ksiazek, Thomas G.; Nichol, Stuart T.

    2008-01-01

    Rift Valley fever (RVF) virus historically has caused widespread and extensive outbreaks of severe human and livestock disease throughout Africa, Madagascar, and the Arabian Peninsula. Following unusually heavy rainfall during the late autumn of 2006, reports of human and animal illness consistent with RVF virus infection emerged across semiarid regions of the Garissa District of northeastern Kenya and southern Somalia. Following initial RVF virus laboratory confirmation, a high-throughput RVF diagnostic facility was established at the Kenyan Central Veterinary Laboratories in Kabete, Kenya, to support the real-time identification of infected livestock and to facilitate outbreak response and control activities. A total of 3,250 specimens from a variety of animal species, including domesticated livestock (cattle, sheep, goats, and camels) and wildlife collected from a total of 55 of 71 Kenyan administrative districts, were tested by molecular and serologic assays. Evidence of RVF infection was found in 9.2% of animals tested and across 23 districts of Kenya, reflecting the large number of affected livestock and the geographic extent of the outbreak. The complete S, M, and/or L genome segment sequence was obtained from a total of 31 RVF virus specimens spanning the entire known outbreak period (December-May) and geographic areas affected by RVF virus activity. Extensive genomic analyses demonstrated the concurrent circulation of multiple virus lineages, gene segment reassortment, and the common ancestry of the 2006/2007 outbreak viruses with those from the 1997-1998 east African RVF outbreak. Evidence of recent increases in genomic diversity and effective population size 2 to 4 years prior to the 2006-2007 outbreak also was found, indicating ongoing RVF virus activity and evolution during the interepizootic/epidemic period. These findings have implications for further studies of basic RVF virus ecology and the design of future surveillance/diagnostic activities, and

  18. The First Prediction of a Rift Valley Fever Outbreak

    NASA Technical Reports Server (NTRS)

    Anyamba, Assaf; Chretien, Jean-Paul; Small, Jennifer; Tucker, Compton J.; Formenty, Pierre; Richardson, Jason H.; Britch, Seth C.; Schnabel, David C.; Erickson, Ralph L.; Linthicum, Kenneth J.

    2009-01-01

    El Nino/Southern Oscillation (ENSO) related anomalies were analyzed using a combination of satellite measurements of elevated sea surface temperatures, and subsequent elevated rainfall and satellite derived normalized difference vegetation index data. A Rift Valley fever risk mapping model using these climate data predicted areas where outbreaks of Rift Valley fever in humans and animals were expected and occurred in the Horn of Africa from December 2006 to May 2007. The predictions were subsequently confirmed by entomological and epidemiological field investigations of virus activity in the areas identified as at risk. Accurate spatial and temporal predictions of disease activity, as it occurred first in southern Somalia and then through much of Kenya before affecting northern Tanzania, provided a 2 to 6 week period of warning for the Horn of Africa that facilitated disease outbreak response and mitigation activities. This is the first prospective prediction of a Rift Valley fever outbreak.

  19. Rift Valley Fever Outbreaks in Mauritania and Related Environmental Conditions

    PubMed Central

    Caminade, Cyril; Ndione, Jacques A.; Diallo, Mawlouth; MacLeod, Dave A.; Faye, Ousmane; Ba, Yamar; Dia, Ibrahima; Morse, Andrew P.

    2014-01-01

    Four large outbreaks of Rift Valley Fever (RVF) occurred in Mauritania in 1998, 2003, 2010 and 2012 which caused lots of animal and several human deaths. We investigated rainfall and vegetation conditions that might have impacted on RVF transmission over the affected regions. Our results corroborate that RVF transmission generally occurs during the months of September and October in Mauritania, similarly to Senegal. The four outbreaks were preceded by a rainless period lasting at least a week followed by heavy precipitation that took place during the second half of the rainy season. First human infections were generally reported three to five weeks later. By bridging the gap between meteorological forecasting centers and veterinary services, an early warning system might be developed in Senegal and Mauritania to warn decision makers and health services about the upcoming RVF risk. PMID:24413703

  20. 77 FR 68783 - Prospective Grant of Exclusive License: Veterinary Vaccines for Rift Valley Fever Virus

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-16

    ...: Veterinary Vaccines for Rift Valley Fever Virus AGENCY: Centers for Disease Control and Prevention (CDC... Rift Valley Fever Virus Utilizing Reverse Genetics,'' US Provisional Application 61/ ] 042,987, filed 4/7/2008, entitled ``Recombinant Rift Valley Fever (RVF) Viruses and Method of Use,'' PCT...

  1. Molecular biology and genetic diversity of Rift Valley fever virus

    PubMed Central

    Ikegami, Tetsuro

    2013-01-01

    Rift Valley fever virus (RVFV), a member of the family Bunyaviridae, genus Phlebovirus, is the causative agent of Rift Valley fever (RVF), a mosquito-borne disease of ruminant animals and humans. The generation of a large sequence database has facilitated studies of the evolution and spread of the virus. Bayesian analyses indicate that currently circulating strains of RVFV are descended from an ancestral species that emerged from a natural reservoir in Africa when large-scale cattle and sheep farming were introduced during the 19th century. Viruses descended from multiple lineages persist in that region, through infection of reservoir animals and vertical transmission in mosquitoes, emerging in years of heavy rainfall to cause epizootics and epidemics. On a number of occasions, viruses from these lineages have been transported outside the enzootic region through the movement of infected animals or mosquitoes, triggering outbreaks in countries such as Egypt, Saudi Arabia, Mauritania and Madagascar, where RVF had not previously been seen. Such viruses could potentially become established in their new environments through infection of wild and domestic ruminants and other animals and vertical transmission in local mosquito species. Despite their extensive geographic dispersion, all strains of RVFV remain closely related at the nucleotide and amino acid level. The high degree of conservation of genes encoding the virion surface glycoproteins suggests that a single vaccine should protect against all currently circulating RVFV strains. Similarly, preservation of the sequence of the RNA-dependent RNA polymerase across viral lineages implies that antiviral drugs targeting the enzyme should be effective against all strains. Researchers should be encouraged to collect additional RVFV isolates and perform whole-genome sequencing and phylogenetic analysis, so as to enhance our understanding of the continuing evolution of this important virus. This review forms part of a series

  2. Rift Valley fever Entomology, Ecology, and Outbreak Risk Factors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a mosquito-borne zoonotic disease of domestic ruminants and humans in Africa. The disease is most severe in cattle, sheep, and goats, and it causes high mortality in young animals and abortion in adults. Exotic aanimal breeds from areas where RVF is not endemic tend to be ...

  3. Rift Valley Fever Overview and Recent Developments at USDA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a mosquito-borne viral disease with significant health and economic impacts to domestic animals and humans in much of sub-Saharan Africa. Human infections are believed to occur mainly from mosquito bites and from infectious aerosols. The available strategies for protection...

  4. Predicting the Next Outbreak of Rift Valley Fever (RVF)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a mosquito-borne zoonotic disease of domestic ruminants in Africa. The disease is most severe in cattle, sheep, and goats, and it causes high mortality in young animals and abortion in adults. Exotic aanimal breeds from areas where RVF is not endemic tend to be more suscep...

  5. Potential for Rift Valley to be Introduced into North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a mosquito-borne zoonotic disease of domestic ruminants in Africa. The disease is most severe in cattle, sheep, and goats, causing mortality in young animals and abortion in adults. Human infection causes significant morbidity and mortality. RVF occurs in sub-Saharan Afri...

  6. Development of a sheep challenge model for Rift Valley fever

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever is a zoonotic disease responsible for severe outbreaks in ruminant livestock characterized by mass abortion and high mortality rates in younger animals. The lack of a fully licensed vaccine in the US has spurred increased demand for a protective vaccine. Thus, development of a reli...

  7. Development of a sheep challenge model for Rift Valley fever

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a zoonotic disease that causes severe epizootic disease in ruminants, characterized by mass abortion and high mortality rates in younger animals. The development of a reliable challenge model is an important prerequisite for evaluation of existing and novel vaccines. A stu...

  8. Comparing Two Profiles: The Amazing Size of the Rift Valleys.

    ERIC Educational Resources Information Center

    Housepian, Jean

    1983-01-01

    Describes an activity for grade 7-9 students previously introduced to topographic maps and profile lines. Two profiles of equal scale are used to help students appreciate the tremendous size of mid-ocean rift valleys. Procedures and examples of completed profiles are provided. (JN)

  9. Complete Genome Sequence of Rift Valley Fever Virus Strain Lunyo

    PubMed Central

    Horton, Daniel L.; Marston, Denise A.; Johnson, Nicholas; Ellis, Richard J.; Fooks, Anthony R.; Hewson, Roger

    2016-01-01

    Using next-generation sequencing technologies, the first complete genome sequence of Rift Valley fever virus strain Lunyo is reported here. Originally reported as an attenuated antigenic variant strain from Uganda, genomic sequence analysis shows that Lunyo clusters together with other Ugandan isolates. PMID:27081121

  10. Potential Effects of Rift Valley Fever in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV) has been the cause of disease outbreaks throughout Africa and the Arabian Peninsula, and the infection often results in heavy economic costs through loss of livestock. If RVFV, which is common to select agent lists of the US Department of Health and Human Services and ...

  11. Rift Valley Fever: International Coordinated Efforts from Early Warning to Rapid Responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scientists at the USDA, ARS, Arthropod-Borne Animal Diseases Research Laboratory (ABADRL) initiated research to develop operator-safe, rapid diagnostic tests and develop large animal models for both virulent and vaccine strains of Rift Valley Fever (RVF). The ABADRL currently does not have biologica...

  12. Potential for stable flies and house flies (Diptera: Muscidae) to transmit Rift Valley fever virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF), a disease of ruminants and humans, has been responsible for large outbreaks in Africa that have resulted in hundreds of thousands of human infections and major economic disruption due to loss of livestock and to trade restrictions. As indicated by the rapid spread of West N...

  13. A recombinant Rift Valley fever virus glycoprotein subunit vaccine confers full protection against Rift Valley fever challenge in sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen causing disease outbreaks in Africa and the Arabian Peninsula. The virus has great potential for transboundary spread due to the presence of competent vectors in non-endemic areas. There is currently no fully licensed vaccine suita...

  14. Interepidemic Rift Valley Fever Virus Seropositivity, Northeastern Kenya

    PubMed Central

    Muchiri, Eric M.; Ndzovu, Malik; Mwanje, Mariam T.; Muiruri, Samuel; Peters, Clarence J.; King, Charles H.

    2008-01-01

    Most outbreaks of Rift Valley fever (RVF) occur in remote locations after floods. To determine environmental risk factors and long-term sequelae of human RVF, we examined rates of previous Rift Valley fever virus (RVFV) exposure by age and location during an interepidemic period in 2006. In a randomized household cluster survey in 2 areas of Ijara District, Kenya, we examined 248 residents of 2 sublocations, Gumarey (village) and Sogan-Godud (town). Overall, the RVFV seropositivity rate was 13% according to immunoglobulin G ELISA; evidence of interepidemic RVFV transmission was detected. Increased seropositivity was found among older persons, those who were male, those who lived in the rural village (Gumarey), and those who had disposed of animal abortus. Rural Gumarey reported more mosquito and animal exposure than Sogan-Godud. Seropositive persons were more likely to have visual impairment and retinal lesions; other physical findings did not differ. PMID:18680647

  15. Potential for Autoimmune Pathogenesis of Rift Valley Fever Virus Retinitis

    PubMed Central

    Newman-Gerhardt, Shoshana; Muiruri, Samuel; Muchiri, Eric; Peters, Clarence J.; Morrill, John; Lucas, Alexander H.; King, Charles H.; Kazura, James; LaBeaud, Angelle Desiree

    2013-01-01

    Rift Valley Fever (RVF) is a significant threat to human health because it can progress to retinitis, encephalitis, and hemorrhagic fever. The timing of onset of Rift Valley Fever virus (RVFV) retinitis suggests an autoimmune origin. To determine whether RVFV retinitis is associated with increased levels of IgG against retinal tissue, we measured and compared levels of IgG against healthy human eye tissue by immunohistochemical analysis. We found that serum samples from RVFV-exposed Kenyans with retinitis (n = 8) were slightly more likely to have antibodies against retinal tissue than control populations, but the correlation was not statistically significant. Further investigation into the possible immune pathogenesis of RVFV retinitis could lead to improved therapies to prevent or treat this severe complication. PMID:23918215

  16. Rift Valley Fever Virus Infection in Golden Syrian Hamsters

    PubMed Central

    Scharton, Dionna; Van Wettere, Arnaud J.; Bailey, Kevin W.; Vest, Zachary; Westover, Jonna B.; Siddharthan, Venkatraman; Gowen, Brian B.

    2015-01-01

    Rift Valley fever virus (RVFV) is a formidable pathogen that causes severe disease and abortion in a variety of livestock species and a range of disease in humans that includes hemorrhagic fever, fulminant hepatitis, encephalitis and blindness. The natural transmission cycle involves mosquito vectors, but exposure can also occur through contact with infected fluids and tissues. The lack of approved antiviral therapies and vaccines for human use underlies the importance of small animal models for proof-of-concept efficacy studies. Several mouse and rat models of RVFV infection have been well characterized and provide useful systems for the study of certain aspects of pathogenesis, as well as antiviral drug and vaccine development. However, certain host-directed therapeutics may not act on mouse or rat pathways. Here, we describe the natural history of disease in golden Syrian hamsters challenged subcutaneously with the pathogenic ZH501 strain of RVFV. Peracute disease resulted in rapid lethality within 2 to 3 days of RVFV challenge. High titer viremia and substantial viral loads were observed in most tissues examined; however, histopathology and immunostaining for RVFV antigen were largely restricted to the liver. Acute hepatocellular necrosis associated with a strong presence of viral antigen in the hepatocytes indicates that fulminant hepatitis is the likely cause of mortality. Further studies to assess the susceptibility and disease progression following respiratory route exposure are warranted. The use of the hamsters to model RVFV infection is suitable for early stage antiviral drug and vaccine development studies. PMID:25607955

  17. Rift Valley Fever: An Emerging Mosquito-Borne Disease.

    PubMed

    Linthicum, Kenneth J; Britch, Seth C; Anyamba, Assaf

    2016-01-01

    Rift Valley fever (RVF), an emerging mosquito-borne zoonotic infectious viral disease caused by the RVF virus (RVFV) (Bunyaviridae: Phlebovirus), presents significant threats to global public health and agriculture in Africa and the Middle East. RVFV is listed as a select agent with significant potential for international spread and use in bioterrorism. RVFV has caused large, devastating periodic epizootics and epidemics in Africa over the past ∼60 years, with severe economic and nutritional impacts on humans from illness and livestock loss. In the past 15 years alone, RVFV caused tens of thousands of human cases, hundreds of human deaths, and more than 100,000 domestic animal deaths. Cattle, sheep, goats, and camels are particularly susceptible to RVF and serve as amplifying hosts for the virus. This review highlights recent research on RVF, focusing on vectors and their ecology, transmission dynamics, and use of environmental and climate data to predict disease outbreaks. Important directions for future research are also discussed. PMID:26982443

  18. Kantis: A new Australopithecus site on the shoulders of the Rift Valley near Nairobi, Kenya.

    PubMed

    Mbua, Emma; Kusaka, Soichiro; Kunimatsu, Yutaka; Geraads, Denis; Sawada, Yoshihiro; Brown, Francis H; Sakai, Tetsuya; Boisserie, Jean-Renaud; Saneyoshi, Mototaka; Omuombo, Christine; Muteti, Samuel; Hirata, Takafumi; Hayashida, Akira; Iwano, Hideki; Danhara, Tohru; Bobe, René; Jicha, Brian; Nakatsukasa, Masato

    2016-05-01

    Most Plio-Pleistocene sites in the Gregory Rift Valley that have yielded abundant fossil hominins lie on the Rift Valley floor. Here we report a new Pliocene site, Kantis, on the shoulder of the Gregory Rift Valley, which extends the geographical range of Australopithecus afarensis to the highlands of Kenya. This species, known from sites in Ethiopia, Tanzania, and possibly Kenya, is believed to be adapted to a wide spectrum of habitats, from open grassland to woodland. The Kantis fauna is generally similar to that reported from other contemporaneous A. afarensis sites on the Rift Valley floor. However, its faunal composition and stable carbon isotopic data from dental enamel suggest a stronger C4 environment than that present at those sites. Although the Gregory Rift Valley has been the focus of paleontologists' attention for many years, surveys of the Rift shoulder may provide new perspective on African Pliocene mammal and hominin evolution. PMID:27178456

  19. Evaporation estimation of rift valley lakes: comparison of models.

    PubMed

    Melesse, Assefa M; Abtew, Wossenu; Dessalegne, Tibebe

    2009-01-01

    Evapotranspiration (ET) accounts for a substantial amount of the water flux in the arid and semi-arid regions of the World. Accurate estimation of ET has been a challenge for hydrologists, mainly because of the spatiotemporal variability of the environmental and physical parameters governing the latent heat flux. In addition, most available ET models depend on intensive meteorological information for ET estimation. Such data are not available at the desired spatial and temporal scales in less developed and remote parts of the world. This limitation has necessitated the development of simple models that are less data intensive and provide ET estimates with acceptable level of accuracy. Remote sensing approach can also be applied to large areas where meteorological data are not available and field scale data collection is costly, time consuming and difficult. In areas like the Rift Valley regions of Ethiopia, the applicability of the Simple Method (Abtew Method) of lake evaporation estimation and surface energy balance approach using remote sensing was studied. The Simple Method and a remote sensing-based lake evaporation estimates were compared to the Penman, Energy balance, Pan, Radiation and Complementary Relationship Lake Evaporation (CRLE) methods applied in the region. Results indicate a good correspondence of the models outputs to that of the above methods. Comparison of the 1986 and 2000 monthly lake ET from the Landsat images to the Simple and Penman Methods show that the remote sensing and surface energy balance approach is promising for large scale applications to understand the spatial variation of the latent heat flux. PMID:22303142

  20. Rift Valley Fever and a New Paradigm of Research and Development for Zoonotic Disease Control

    PubMed Central

    McIntyre, Sabrina; Hogarth, Sue; Heymann, David

    2013-01-01

    Although Rift Valley fever is a disease that, through its wider societal effects, disproportionately affects vulnerable communities with poor resilience to economic and environmental challenge, Rift Valley fever virus has since its discovery in 1931 been neglected by major global donors and disease control programs. We describe recent outbreaks affecting humans and animals and discuss the serious socioeconomic effects on the communities affected and the slow pace of development of new vaccines. We also discuss the mixed global response, which has largely been fueled by the classification of the virus as a potential bioterrorism agent and its potential to migrate beyond its traditional eastern African boundaries. We argue for a refocus of strategy with increased global collaboration and a greater sense of urgency and investment that focuses on an equity-based approach in which funding and research are prioritized by need, inspired by principles of equity and social justice. PMID:23347653

  1. Rift valley fever in the US: Commerce networks, climate, and susceptible vector and host populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a mosquito-borne hemorrhagic viral disease with substantial negative impacts on public and animal health in its endemic range of sub-Saharan Africa. Rift Valley fever virus (RVFV) could enter the United States and lead to widespread morbidity and mortality in humans, domes...

  2. A network-based meta-population approach to model Rift Valley fever epidemics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV) has been expanding its geographical distribution with important implications for both human and animal health. The emergence of Rift Valley fever (RVF) in the Middle East, and its continuing presence in many areas of Africa, has negatively impacted both medical and vet...

  3. Indirect detection of subsurface outflow from a rift valley lake

    NASA Astrophysics Data System (ADS)

    Darling, W. G.; Allen, D. J.; Armannsson, H.

    1990-02-01

    Naivasha, highest of the Kenya (Gregory) Rift Valley lakes, has no surface outlet. However, unlike other Rift lakes it has not become saline despite high potential evaporation rates, which indicates that there must be some subsurface drainage. The fate of this outflow has been the subject of speculation for many years, especially during the general decline in lake water level during the 1980's. Particularly to the south of the lake, there are few opportunities to obtain information from direct groundwater sampling. However, the stable isotopic composition of fumarole steam from late Quaternary volcanic centres in the area has been used to infer groundwater composition. Using a simple mixing model between Rift-flank groundwater and highly-evaporated lakewater, this has enabled subsurface water flow to be contoured by its lakewater content. By this method, outflow can still be detected some 30 km to the south of the lake. Stable isotope data also confirm that much of the steam used by the local Olkaria geothermal power station is derived from lakewater, though simple balance considerations show that steam use cannot alone be responsible for the fall in lake level observed during the 1980's.

  4. Modeling the Spatial Spread of Rift Valley Fever in Egypt

    PubMed Central

    Gao, Daozhou; Cosner, Chris; Cantrell, Robert Stephen; Beier, John C.; Ruan, Shigui

    2013-01-01

    Rift Valley fever (RVF) is a severe viral zoonosis in Africa and the Middle East that harms both human health and livestock production. It is believed that RVF in Egypt has been repeatedly introduced by the importation of infected animals from Sudan. In this paper, we propose a three-patch model for the process by which animals enter Egypt from Sudan, are moved up the Nile, and then consumed at population centers. The basic reproduction number for each patch is introduced and then the threshold dynamics of the model are established. We simulate an interesting scenario showing a possible explanation of the observed phenomenon of the geographic spread of RVF in Egypt. PMID:23377629

  5. Rift Valley Fever during Rainy Seasons, Madagascar, 2008 and 2009

    PubMed Central

    Andriamandimby, Soa Fy; Randrianarivo-Solofoniaina, Armand Eugène; Jeanmaire, Elisabeth M.; Ravololomanana, Lisette; Razafimanantsoa, Lanto Tiana; Rakotojoelinandrasana, Tsanta; Razainirina, Josette; Hoffmann, Jonathan; Ravalohery, Jean-Pierre; Rafisandratantsoa, Jean-Théophile; Rollin, Pierre E.

    2010-01-01

    During 2 successive rainy seasons, January 2008 through May 2008 and November 2008 through March 2009, Rift Valley fever virus (RVFV) caused outbreaks in Madagascar. Human and animal infections were confirmed on the northern and southern coasts and in the central highlands. Analysis of partial sequences from RVFV strains showed that all were similar to the strains circulating in Kenya during 2006–2007. A national cross-sectional serologic survey among slaughterhouse workers at high risk showed that RVFV circulation during the 2008 outbreaks included all of the Malagasy regions and that the virus has circulated in at least 92 of Madagascar’s 111 districts. To better predict and respond to RVF outbreaks in Madagascar, further epidemiologic studies are needed, such as RVFV complete genome analysis, ruminant movement mapping, and surveillance implementation. PMID:20507747

  6. The Risk of Nosocomial Transmission of Rift Valley Fever

    PubMed Central

    Al-Hamdan, Nasser A.; Panackal, Anil A.; Al Bassam, Tami H.; Alrabea, Abdullah; Al Hazmi, Mohammed; Al Mazroa, Yagoub; Al Jefri, Mohammed; Khan, Ali S.; Ksiazek, Thomas G.

    2015-01-01

    In 2000, we investigated the Rift Valley fever (RVF) outbreak on the Arabian Peninsula—the first outside Africa—and the risk of nosocomial transmission. In a cross-sectional design, during the peak of the epidemic at its epicenter, we found four (0.6%) of 703 healthcare workers (HCWs) IgM seropositive but all with only community-associated exposures. Standard precautions are sufficient for HCWs exposed to known RVF patients, in contrast to other viral hemorrhagic fevers (VHF) such as Ebola virus disease (EVD) in which the route of transmission differs. Suspected VHF in which the etiology is uncertain should be initially managed with the most cautious infection control measures. PMID:26694834

  7. Ultrastructural pathology of human liver in Rift Valley fever.

    PubMed

    Shraim, Mubarak Al; Eid, Refaat; Radad, Khaled; Saeed, Noora

    2016-01-01

    Rift Valley fever (RVF) is a zoonotic disease that primarily affects ruminant animals and can also cause fatal disease in humans. In the current report, we present the ultrastructural changes in the liver of a man aged 60 years who died from RVF in the Aseer Central Hospital, Abha, Saudi Arabia. The main hepatic changes by transmission electron microscopy included the presence of 95-115 nm electron-dense particles consistent with RVF virions, nuclear condensation, vacuolar degeneration, lipid droplet accumulation and mitochondrial damage and dilation. There were also viral inclusion bodies with electron-dense aggregates, dilation of intercellular spaces, damage of sinusoidal microvilli with widening of space of Disse, dilation of bile canaliculi and increasing number of phagolysosomes. PMID:27485877

  8. Potential for North American Mosquitoes (Diptera: Culicidae) to Transmit Rift Valley Fever Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To determine which biting insects should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America, we evaluated Culex erraticus, Culex erythrothorax, Culex pipiens, Culex quinquefasciatus, Culex tarsalis, Aedes dorsalis, Aedes vexans, Anopheles quadrimaculatus, and ...

  9. The geographic distribution of fluoride in surface and groundwater in Ethiopia with an emphasis on the Rift Valley.

    PubMed

    Tekle-Haimanot, Redda; Melaku, Zenebe; Kloos, Helmut; Reimann, Clemens; Fantaye, Wondwossen; Zerihun, Legesse; Bjorvatn, Kjell

    2006-08-15

    This paper analyzes the most extensive database on fluoride distribution in Ethiopia. Of the total 1438 water samples tested, 24.2% had fluoride concentrations above the 1.5 mg/l recommended optimum concentration recommended by WHO. Regionally, by far the highest fluoride levels were recorded in the Rift Valley, where 41.2% of all samples exceeded the 1.5 mg/l level. Only 1.0% of the samples from the central and northwestern highlands and 10.0% in the southeastern highlands exceeded 1.5 mg/l. Larger proportions of deep wells (50.0%) and hot springs (90.0%) than shallow wells (27.2%) and cold springs (12.6%) exceeded the 1.5 mg/l level. The highest fluoride concentrations were recorded for Rift Valley lakes Shala (264.0 mg/l) and Abijata (202.4 mg/l) and the lowest in Lake Tana, and rivers, wells and springs in the highlands. The fluoride concentrations of the Awash River, which originates in the highlands and flows through the Rift Valley, increase downstream, giving concern over the current diversion of high-fluoride water from Lake Beseka. Of the various flourosis prevention methods tried in Ethiopia, the treatment of surface water has been shown to be the most feasible and effective for towns and large commercial farms in the Rift Valley, although defluoridation methods should be considered for smaller rural communities. PMID:16360195

  10. Single-cycle replicable Rift Valley fever virus mutants as safe vaccine candidates.

    PubMed

    Terasaki, Kaori; Tercero, Breanna R; Makino, Shinji

    2016-05-01

    Rift Valley fever virus (RVFV) is an arbovirus circulating between ruminants and mosquitoes to maintain its enzootic cycle. Humans are infected with RVFV through mosquito bites or direct contact with materials of infected animals. The virus causes Rift Valley fever (RVF), which was first recognized in the Great Rift Valley of Kenya in 1931. RVF is characterized by a febrile illness resulting in a high rate of abortions in ruminants and an acute febrile illness, followed by fatal hemorrhagic fever and encephalitis in humans. Initially, the virus was restricted to the eastern region of Africa, but the disease has now spread to southern and western Africa, as well as outside of the African continent, e.g., Madagascar, Saudi Arabia and Yemen. There is a serious concern that the virus may spread to other areas, such as North America and Europe. As vaccination is an effective tool to control RVFV epidemics, formalin-inactivated vaccines and live-attenuated RVFV vaccines have been used in endemic areas. The formalin-inactivated vaccines require boosters for effective protection, whereas the live-attenuated vaccines enable the induction of protective immunity by a single vaccination. However, the use of live-attenuated RVFV vaccines for large human populations having a varied health status is of concern, because of these vaccines' residual neuro-invasiveness and neurovirulence. Recently, novel vaccine candidates have been developed using replication-defective RVFV that can undergo only a single round of replication in infected cells. The single-cycle replicable RVFV does not cause systemic infection in immunized hosts, but enables the conferring of protective immunity. This review summarizes the properties of various RVFV vaccines and recent progress on the development of the single-cycle replicable RVFV vaccines. PMID:26022573

  11. Spatial and Temporal Pattern of Rift Valley Fever Outbreaks in Tanzania; 1930 to 2007

    PubMed Central

    Sindato, Calvin; Karimuribo, Esron D.; Pfeiffer, Dirk U.; Mboera, Leonard E. G.; Kivaria, Fredrick; Dautu, George; Bernard, Bett; Paweska, Janusz T.

    2014-01-01

    Background Rift Valley fever (RVF)-like disease was first reported in Tanzania more than eight decades ago and the last large outbreak of the disease occurred in 2006–07. This study investigates the spatial and temporal pattern of RVF outbreaks in Tanzania over the past 80 years in order to guide prevention and control strategies. Materials and Methods A retrospective study was carried out based on disease reporting data from Tanzania at district or village level. The data were sourced from the Ministries responsible for livestock and human health, Tanzania Meteorological Agency and research institutions involved in RVF surveillance and diagnosis. The spatial distribution of outbreaks was mapped using ArcGIS 10. The space-time permutation model was applied to identify clusters of cases, and a multivariable logistic regression model was used to identify risk factors associated with the occurrence of outbreaks in the district. Principal Findings RVF outbreaks were reported between December and June in 1930, 1947, 1957, 1960, 1963, 1968, 1977–79, 1989, 1997–98 and 2006–07 in 39.2% of the districts in Tanzania. There was statistically significant spatio-temporal clustering of outbreaks. RVF occurrence was associated with the eastern Rift Valley ecosystem (OR = 6.14, CI: 1.96, 19.28), total amount of rainfall of >405.4 mm (OR = 12.36, CI: 3.06, 49.88), soil texture (clay [OR = 8.76, CI: 2.52, 30.50], and loam [OR = 8.79, CI: 2.04, 37.82]). Conclusion/Significance RVF outbreaks were found to be distributed heterogeneously and transmission dynamics appeared to vary between areas. The sequence of outbreak waves, continuously cover more parts of the country. Whenever infection has been introduced into an area, it is likely to be involved in future outbreaks. The cases were more likely to be reported from the eastern Rift Valley than from the western Rift Valley ecosystem and from areas with clay and loam rather than sandy soil texture. PMID:24586433

  12. Persistence of Rift Valley fever virus in East Africa

    NASA Astrophysics Data System (ADS)

    Gachohi, J.; Hansen, F.; Bett, B.; Kitala, P.

    2012-04-01

    Rift Valley fever virus (RVFv) is a mosquito-borne pathogen of livestock, wildlife and humans that causes severe outbreaks in intervals of several years. One of the open questions is how the virus persists between outbreaks. We developed a spatially-explicit, individual-based simulation model of the RVFv transmission dynamics to investigate this question. The model, is based on livestock and mosquito population dynamics. Spatial aspects are explicitly represented by a set of grid cells that represent mosquito breeding sites. A grid cell measures 500 by 500m and the model considers a grid of 100 by 100 grid cells; the model thus operates on the regional scale of 2500km2. Livestock herds move between grid cells, and provide connectivity between the cells. The model is used to explore the spatio-temporal dynamics of RVFv persistence in absence of a wildlife reservoir in an east African semi-arid context. Specifically, the model assesses the importance of local virus persistence in mosquito breeding sites relative to global virus persistence mitigated by movement of hosts. Local persistence is determined by the length of time the virus remains in a mosquito breeding site once introduced. In the model, this is a function of the number of mosquitoes that emerge infected and their lifespan. Global persistence is determined by the level of connectivity between isolated grid cells. Our work gives insights into the ecological and epidemiological conditions under which RVFv persists. The implication for disease surveillance and management are discussed.

  13. An Assembly Model of Rift Valley Fever Virus

    PubMed Central

    Rusu, Mirabela; Bonneau, Richard; Holbrook, Michael R.; Watowich, Stanley J.; Birmanns, Stefan; Wriggers, Willy; Freiberg, Alexander N.

    2012-01-01

    Rift Valley fever virus (RVFV) is a bunyavirus endemic to Africa and the Arabian Peninsula that infects humans and livestock. The virus encodes two glycoproteins, Gn and Gc, which represent the major structural antigens and are responsible for host cell receptor binding and fusion. Both glycoproteins are organized on the virus surface as cylindrical hollow spikes that cluster into distinct capsomers with the overall assembly exhibiting an icosahedral symmetry. Currently, no experimental three-dimensional structure for any entire bunyavirus glycoprotein is available. Using fold recognition, we generated molecular models for both RVFV glycoproteins and found significant structural matches between the RVFV Gn protein and the influenza virus hemagglutinin protein and a separate match between RVFV Gc protein and Sindbis virus envelope protein E1. Using these models, the potential interaction and arrangement of both glycoproteins in the RVFV particle was analyzed, by modeling their placement within the cryo-electron microscopy density map of RVFV. We identified four possible arrangements of the glycoproteins in the virion envelope. Each assembly model proposes that the ectodomain of Gn forms the majority of the protruding capsomer and that Gc is involved in formation of the capsomer base. Furthermore, Gc is suggested to facilitate intercapsomer connections. The proposed arrangement of the two glycoproteins on the RVFV surface is similar to that described for the alphavirus E1-E2 proteins. Our models will provide guidance to better understand the assembly process of phleboviruses and such structural studies can also contribute to the design of targeted antivirals. PMID:22837754

  14. Protein Phosphatase-1 regulates Rift Valley fever virus replication.

    PubMed

    Baer, Alan; Shafagati, Nazly; Benedict, Ashwini; Ammosova, Tatiana; Ivanov, Andrey; Hakami, Ramin M; Terasaki, Kaori; Makino, Shinji; Nekhai, Sergei; Kehn-Hall, Kylene

    2016-03-01

    Rift Valley fever virus (RVFV), genus Phlebovirus family Bunyaviridae, is an arthropod-borne virus endemic throughout sub-Saharan Africa. Recent outbreaks have resulted in cyclic epidemics with an increasing geographic footprint, devastating both livestock and human populations. Despite being recognized as an emerging threat, relatively little is known about the virulence mechanisms and host interactions of RVFV. To date there are no FDA approved therapeutics or vaccines for RVF and there is an urgent need for their development. The Ser/Thr protein phosphatase 1 (PP1) has previously been shown to play a significant role in the replication of several viruses. Here we demonstrate for the first time that PP1 plays a prominent role in RVFV replication early on during the viral life cycle. Both siRNA knockdown of PP1α and a novel PP1-targeting small molecule compound 1E7-03, resulted in decreased viral titers across several cell lines. Deregulation of PP1 was found to inhibit viral RNA production, potentially through the disruption of viral RNA transcript/protein interactions, and indicates a potential link between PP1α and the viral L polymerase and nucleoprotein. These results indicate that PP1 activity is important for RVFV replication early on during the viral life cycle and may prove an attractive therapeutic target. PMID:26801627

  15. Chimpanzee Adenovirus Vaccine Provides Multispecies Protection against Rift Valley Fever

    PubMed Central

    Warimwe, George M.; Gesharisha, Joseph; Carr, B. Veronica; Otieno, Simeon; Otingah, Kennedy; Wright, Danny; Charleston, Bryan; Okoth, Edward; Elena, Lopez-Gil; Lorenzo, Gema; Ayman, El-Behiry; Alharbi, Naif K.; Al-dubaib, Musaad A.; Brun, Alejandro; Gilbert, Sarah C.; Nene, Vishvanath; Hill, Adrian V. S.

    2016-01-01

    Rift Valley Fever virus (RVFV) causes recurrent outbreaks of acute life-threatening human and livestock illness in Africa and the Arabian Peninsula. No licensed vaccines are currently available for humans and those widely used in livestock have major safety concerns. A ‘One Health’ vaccine development approach, in which the same vaccine is co-developed for multiple susceptible species, is an attractive strategy for RVFV. Here, we utilized a replication-deficient chimpanzee adenovirus vaccine platform with an established human and livestock safety profile, ChAdOx1, to develop a vaccine for use against RVFV in both livestock and humans. We show that single-dose immunization with ChAdOx1-GnGc vaccine, encoding RVFV envelope glycoproteins, elicits high-titre RVFV-neutralizing antibody and provides solid protection against RVFV challenge in the most susceptible natural target species of the virus-sheep, goats and cattle. In addition we demonstrate induction of RVFV-neutralizing antibody by ChAdOx1-GnGc vaccination in dromedary camels, further illustrating the potency of replication-deficient chimpanzee adenovirus vaccine platforms. Thus, ChAdOx1-GnGc warrants evaluation in human clinical trials and could potentially address the unmet human and livestock vaccine needs. PMID:26847478

  16. Climate-disease connections: Rift Valley Fever in Kenya

    NASA Technical Reports Server (NTRS)

    Anyamba, A.; Linthicum, K. J.; Tucker, C. J.

    2001-01-01

    All known Rift Valley fever(RVF) outbreaks in Kenya from 1950 to 1998 followed periods of abnormally high rainfall. On an interannual scale, periods of above normal rainfall in East Africa are associated with the warm phase of the El Nino/Southern Oscillation (ENSO) phenomenon. Anomalous rainfall floods mosquito-breeding habitats called dambos, which contain transovarially infected mosquito eggs. The eggs hatch Aedes mosquitoes that transmit the RVF virus preferentially to livestock and to humans as well. Analysis of historical data on RVF outbreaks and indicators of ENSO (including Pacific and Indian Ocean sea surface temperatures and the Southern Oscillation Index) indicates that more than three quarters of the RVF outbreaks have occurred during warm ENSO event periods. Mapping of ecological conditions using satellite normalized difference vegetation index (NDVI) data show that areas where outbreaks have occurred during the satellite recording period (1981-1998) show anomalous positive departures in vegetation greenness, an indicator of above-normal precipitation. This is particularly observed in arid areas of East Africa, which are predominantly impacted by this disease. These results indicate a close association between interannual climate variability and RVF outbreaks in Kenya.

  17. A Recombinant Rift Valley Fever Virus Glycoprotein Subunit Vaccine Confers Full Protection against Rift Valley Fever Challenge in Sheep.

    PubMed

    Faburay, Bonto; Wilson, William C; Gaudreault, Natasha N; Davis, A Sally; Shivanna, Vinay; Bawa, Bhupinder; Sunwoo, Sun Young; Ma, Wenjun; Drolet, Barbara S; Morozov, Igor; McVey, D Scott; Richt, Juergen A

    2016-01-01

    Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen causing disease outbreaks in Africa and the Arabian Peninsula. The virus has great potential for transboundary spread due to the presence of competent vectors in non-endemic areas. There is currently no fully licensed vaccine suitable for use in livestock or humans outside endemic areas. Here we report the evaluation of the efficacy of a recombinant subunit vaccine based on the RVFV Gn and Gc glycoproteins. In a previous study, the vaccine elicited strong virus neutralizing antibody responses in sheep and was DIVA (differentiating naturally infected from vaccinated animals) compatible. In the current efficacy study, a group of sheep (n = 5) was vaccinated subcutaneously with the glycoprotein-based subunit vaccine candidate and then subjected to heterologous challenge with the virulent Kenya-128B-15 RVFV strain. The vaccine elicited high virus neutralizing antibody titers and conferred complete protection in all vaccinated sheep, as evidenced by prevention of viremia, fever and absence of RVFV-associated histopathological lesions. We conclude that the subunit vaccine platform represents a promising strategy for the prevention and control of RVFV infections in susceptible hosts. PMID:27296136

  18. A Recombinant Rift Valley Fever Virus Glycoprotein Subunit Vaccine Confers Full Protection against Rift Valley Fever Challenge in Sheep

    PubMed Central

    Faburay, Bonto; Wilson, William C.; Gaudreault, Natasha N.; Davis, A. Sally; Shivanna, Vinay; Bawa, Bhupinder; Sunwoo, Sun Young; Ma, Wenjun; Drolet, Barbara S.; Morozov, Igor; McVey, D. Scott; Richt, Juergen A.

    2016-01-01

    Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen causing disease outbreaks in Africa and the Arabian Peninsula. The virus has great potential for transboundary spread due to the presence of competent vectors in non-endemic areas. There is currently no fully licensed vaccine suitable for use in livestock or humans outside endemic areas. Here we report the evaluation of the efficacy of a recombinant subunit vaccine based on the RVFV Gn and Gc glycoproteins. In a previous study, the vaccine elicited strong virus neutralizing antibody responses in sheep and was DIVA (differentiating naturally infected from vaccinated animals) compatible. In the current efficacy study, a group of sheep (n = 5) was vaccinated subcutaneously with the glycoprotein-based subunit vaccine candidate and then subjected to heterologous challenge with the virulent Kenya-128B-15 RVFV strain. The vaccine elicited high virus neutralizing antibody titers and conferred complete protection in all vaccinated sheep, as evidenced by prevention of viremia, fever and absence of RVFV-associated histopathological lesions. We conclude that the subunit vaccine platform represents a promising strategy for the prevention and control of RVFV infections in susceptible hosts. PMID:27296136

  19. Hot Spot Induced Cenozoic Volcanism in the Upper Rajang Valley, Sarawak - Is Borneo Rifting?

    NASA Astrophysics Data System (ADS)

    Taib, N.

    2010-12-01

    The Upper Rajang Valley covers a large area in the northern interior of the island of Borneo, in the Malaysian state of Sarawak . It is underlain by the Cretaceous to Late Eocene deep to shallow marine sediments of the Rajang Group. Within this area are several Cenozoic volcanic edifices, which to date have been sparsely studied. Two distinct episodes of volcanism are recognized - the first, dated early Eocene, consists of K-rich basalts, and is represented by the Bukit Mersing volcanics, which were erupted conformably onto deep water turbidites of the Rajang Group. The second, far more extensive, is dated Pliocene to Quaternary, and is bimodal, consisting mainly of early dacite and rhyodacite tuffs, with a smaller amount of later basalt, forming several volcanic plateaus and massifs (Hose Mountains, Usun Apau, Linau-Balui, Nieuwenhuis Mountains and others). They lie unconformably over pre-Miocene sediments, the Linau-Balui basalts having been erupted onto Quaternary river terraces. Mantle-normalized REE and incompatible trace element spider plots reveal that the Bukit Mersing basalts have geochemical affinity with Oceanic Island Basalts (OIB) and rift basalts, being enriched in LREEs and Most Incompatible Elements, and no Eu anomaly. Preliminary trace element data for several basalt samples from Usun Apau also show Oceanic Island/Rift affinity. Bimodal volcanism is most often associated with rift environments. Efforts are being made to radiometrically date the volcanics, in part to determine the possibility of future eruptions. The Upper Rajang Valley is remote, covered in tropical rainforest and is very sparsely populated. At this time, there is no information concerning signs of imminent volcanism, such as hot springs and microseismicity.

  20. Response to Rift Valley Fever in Tanzania: Challenges and Opportunities.

    PubMed

    Fyumagwa, Robert D; Ezekiel, Mangi J; Nyaki, Athanas; Mdaki, Maulid L; Katale, Zablon B; Moshiro, Candida; Keyyu, Julius D

    2011-12-01

    Rift Valley Fever (RVF) is an arthropod borne viral disease affecting livestock (cattle, sheep, goats and camels), wildlife and humans caused by Phlebovirus. The disease occurs in periodic cycles of 4-15 years associated with flooding from unusually high precipitations in many flood-prone habitats. Aedes and Culex spp and other mosquito species are important epidemic vectors. Because of poor living conditions and lack of knowledge on the pathogenesis of RVF, nomadic pastoralists and agro-pastoralists are at high risk of contracting the disease during epidemics. RVF is a professional hazard for health and livestock workers because of poor biosafety measures in routine activities including lack of proper Personal Protective Equipment (PPE). Direct exposure to infected animals can occur during handling and slaughter or through veterinary and obstetric procedures or handling of specimens in laboratory. The episodic nature of the disease creates special challenges for its mitigation and control and many of the epidemics happen when the governments are not prepared and have limited resource to contain the disease at source. Since its first description in 1930s Tanzania has recorded six epidemics, three of which were after independence in 1961. However, the 2007 epidemic was the most notable and wide spread with fatal human cases among pastoralists and agro-pastoralists concurrent with high livestock mortality. Given all the knowledge that exist on the epidemiology of the disease, still the 2006/2007 epidemic occurred when the government of Tanzania was not prepared to contain the disease at source. This paper reviews the epidemiology, reporting and outbreak-investigation, public awareness, preparedness plans and policy as well as challenges for its control in Tanzania. PMID:26591988

  1. Rift Valley fever outbreak--Kenya, November 2006-January 2007.

    PubMed

    2007-02-01

    In mid-December 2006, several unexplained fatalities associated with fever and generalized bleeding were reported to the Kenya Ministry of Health (KMOH) from Garissa District in North Eastern Province (NEP). By December 20, a total of 11 deaths had been reported. Of serum samples collected from the first 19 patients, Rift Valley fever (RVF) virus RNA or immunoglobulin M (IgM) antibodies against RVF virus were found in samples from 10 patients; all serum specimens were negative for yellow fever, Ebola, Crimean-Congo hemorrhagic fever, and dengue viruses. The outbreak was confirmed by isolation of RVF virus from six of the specimens. Humans can be infected with RVF virus from bites of mosquitoes or other arthropod vectors that have fed on animals infected with RVF virus, or through contact with viremic animals, particularly livestock. Reports of livestock deaths and unexplained animal abortions in NEP provided further evidence of an RVF outbreak. On December 20, an investigation was launched by KMOH, the Kenya Field Epidemiology and Laboratory Training Program (FELTP), the Kenya Medical Research Institute (KEMRI), the Walter Reed Project of the U.S. Army Medical Research Unit, CDC-Kenya's Global Disease Detection Center, and other partners, including the World Health Organization (WHO) and Médecins Sans Frontières (MSF). This report describes the findings from that initial investigation and the control measures taken in response to the RVF outbreak, which spread to multiple additional provinces and districts, resulting in 404 cases with 118 deaths as of January 25, 2007. PMID:17268404

  2. Curcumin Inhibits Rift Valley Fever Virus Replication in Human Cells*

    PubMed Central

    Narayanan, Aarthi; Kehn-Hall, Kylene; Senina, Svetlana; Lundberg, Lindsay; Van Duyne, Rachel; Guendel, Irene; Das, Ravi; Baer, Alan; Bethel, Laura; Turell, Michael; Hartman, Amy Lynn; Das, Bhaskar; Bailey, Charles; Kashanchi, Fatah

    2012-01-01

    Rift Valley fever virus (RVFV) is an arbovirus that is classified as a select agent, an emerging infectious virus, and an agricultural pathogen. Understanding RVFV-host interactions is imperative to the design of novel therapeutics. Here, we report that an infection by the MP-12 strain of RVFV induces phosphorylation of the p65 component of the NFκB cascade. We demonstrate that phosphorylation of p65 (serine 536) involves phosphorylation of IκBα and occurs through the classical NFκB cascade. A unique, low molecular weight complex of the IKK-β subunit can be observed in MP-12-infected cells, which we have labeled IKK-β2. The IKK-β2 complex retains kinase activity and phosphorylates an IκBα substrate. Inhibition of the IKK complex using inhibitors impairs viral replication, thus alluding to the requirement of an active IKK complex to the viral life cycle. Curcumin strongly down-regulates levels of extracellular infectious virus. Our data demonstrated that curcumin binds to and inhibits kinase activity of the IKK-β2 complex in infected cells. Curcumin partially exerts its inhibitory influence on RVFV replication by interfering with IKK-β2-mediated phosphorylation of the viral protein NSs and by altering the cell cycle of treated cells. Curcumin also demonstrated efficacy against ZH501, the fully virulent version of RVFV. Curcumin treatment down-regulated viral replication in the liver of infected animals. Our data point to the possibility that RVFV infection may result in the generation of novel versions of host components (such as IKK-β2) that, by virtue of altered protein interaction and function, qualify as unique therapeutic targets. PMID:22847000

  3. Potency of a thermostabilised chimpanzee adenovirus Rift Valley Fever vaccine in cattle.

    PubMed

    Dulal, Pawan; Wright, Daniel; Ashfield, Rebecca; Hill, Adrian V S; Charleston, Bryan; Warimwe, George M

    2016-04-29

    Development of safe and efficacious vaccines whose potency is unaffected by long-term storage at ambient temperature would obviate major vaccine deployment hurdles and limit wastage associated with breaks in the vaccine cold chain. Here, we evaluated the immunogenicity of a novel chimpanzee adenovirus vectored Rift Valley Fever vaccine (ChAdOx1-GnGc) in cattle, following its thermostabilisation by slow desiccation on glass fiber membranes in the non-reducing sugars trehalose and sucrose. Thermostabilised ChAdOx1-GnGc vaccine stored for 6 months at 25, 37 or 45 ° C elicited comparable Rift Valley Fever virus neutralising antibody titres to those elicited by the 'cold chain' vaccine (stored at -80 ° C throughout) at the same dose, and these were within the range associated with protection against Rift Valley Fever in cattle. The results support the use of sugar-membrane thermostabilised vaccines in target livestock species. PMID:27020712

  4. Mapping the Risk of Rift Valley fever re-emergence in Southern Africa using remote sensing data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever is a viral disease of animals and humans that occurs throughout sub-Saharan Africa, Egypt and the Arabian Peninsula. Outbreaks of the disease are episodic and closely linked to climate variability, especially widespread elevated rainfall that facilitates Rift Valley fever virus tra...

  5. 77 FR 68783 - Prospective Grant of Co-Exclusive License: Veterinary Vaccines for Rift Valley Fever Virus

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-16

    ...: Veterinary Vaccines for Rift Valley Fever Virus AGENCY: Centers for Disease Control and Prevention (CDC.../016,065, filed 12/21/2007, entitled ``Development of Rift Valley Fever Virus Utilizing Reverse... (RVF) Viruses and Method of Use,'' PCT Application PCT/US2008/087023, filed 12/16/2008,...

  6. Permo-Triassic structural evolution of the Argana Valley, impact of the Atlantic rifting in the High Atlas, Morocco

    NASA Astrophysics Data System (ADS)

    Baudon, Catherine; Redfern, Jonathan; Van Den Driessche, Jean

    2012-04-01

    This paper provides an alternative model to explain the structural evolution of the Argana Valley, located in the Western High Atlas of Morocco. Most Triassic basins in the High Atlas have been described as isolated rift basins distributed along an ENE-WSW oriented trough and developed as a series of half-grabens. They are characterised by two main sets of syn-sedimentary faults striking ENE-WSW and NNE-SSW, generally attributed to the Atlantic and Tethys rifting. The Permo-Triassic sediments of the Argana Valley are offset by similar trending faults and, as such, they have been interpreted as typical infill sediments of narrow rift-basins in Morocco, controlled by syn-sedimentary faulting due to the Atlantic rifting. Our study investigates the structural evolution of the area using newly acquired field analysis of the main faults and unconformities. This data, together with published information, has been used to construct a series of structural cross-sections across the valley. Three main unconformities have been recognised. The first unconformity separates Permian sediments from the underlying deformed Palaeozoic rocks. The second is an angular unconformity between Late Permian sediments and the overlying Triassic sequence, attributed to relaxation and orogenic collapse that occurred after the Hercynian Orogeny. The geometry of Late Permian units suggests that the large E-W to ENE-WSW faults occurred after deposition of the Late Permian and before the Triassic, and were associated with a major phase of tectonic activity and associated erosion. The third angular unconformity occurs between the latest Triassic sediments and the overlying basalts or Jurassic sedimentary sequence. Significantly, this study suggests that the ENE-WSW faults and most of NNE faults were not active during sedimentation of the Triassic. We conclude that the Triassic sediments of the Argana Valley were not deposited in a half graben, but within a slowly subsiding domain, such as a sag

  7. Serological tests for detecting Rift Valley fever viral antibodies in sheep from the Nile Delta.

    PubMed Central

    Scott, R M; Feinsod, F M; Allam, I H; Ksiazek, T G; Peters, C J; Botros, B A; Darwish, M A

    1986-01-01

    To determine the accuracy of serological methods in detecting Rift Valley fever (RVF) viral antibodies, we examined serum samples obtained from 418 sheep in the Nile Delta by using five tests. The plaque reduction neutralization test (PRNT) was considered the standard serological method against which the four other tests were compared. Twenty-four serum samples had RVF viral antibodies detected by PRNT. Hemagglutination inhibition and enzyme-linked immunosorbent assay antibodies to RVF virus were also present in the same 24 serum samples. Indirect immunofluorescence was less sensitive in comparison with PRNT, and complement fixation was the least sensitive. These results extend observations made with laboratory animals to a large field-collected group of Egyptian sheep. PMID:3533977

  8. Negative gravity anomaly over spreading rift valleys: Mid-Atlantic Ridge at 26°N

    NASA Astrophysics Data System (ADS)

    Bowin, Carl; Milligan, Julie

    1985-03-01

    A pronounced negative free-air gravity anomaly commonly occurs over the median valley of slow spreading ocean ridges. Previous results, using Wiener filtering and cross-spectral analysis techniques for the Mid-Atlantic Ridge, obtained estimates of the elastic plate thickness in the range of 7-13 km and the existence of a residual negative gravity anomaly over the median rift valley, suggesting that the rift valley has a response function different than the remainder of the spreading ridge. In this paper we have improved the derivation of the topography-gravity admittance function for spreading ocean crust by carefully avoiding several sources of spectral splattering when processing the data: (1) selecting data from a cruise that followed a flowline of central North Atlantic relative plate motion and hence is least corrupted by fracture zones; and (2) accounting for the difference in distance between the gravity meter and the regional variation in elevation as the ridge crest is traversed. Improvements of lesser importance include the use of cubic splines to interpolate to equally spaced data rather than linear interpolation, and correction of the free-air anomaly values for long-wavelength variations of the indirect effect. Comparison of the resulting admittance function to elastic flexure response functions suggests an elastic plate thickness of about 8 km. The improved admittance function, when convolved with the ridge topography, provides a predicted gravity profile that accounts very well for the negative anomaly over the rift valley. Therefore, the isostatic response function for the rift valley is similar to that for the topography away from the rift valley.

  9. Development of Enzyme-Linked Immunosorbent Assays Using Expressed Proteins of Rift Valley Fever Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV) is a member of the genus Phlebovirus, family Bunyaviridae that can cause severe disease in both humans and animals. The disease is enzootic in sub-Saharan Africa and RVFV epidemics/epizootics occur periodically, primarily in eastern and southern Africa. Since the virus...

  10. Pupils' Environmental Awareness and Knowledge: A Springboard for Action in Primary Schools in Kenya's Rift Valley

    ERIC Educational Resources Information Center

    Mutisya, Sammy M.; Barker, Miles

    2011-01-01

    This study was carried out with 276 standard eight pupils in eleven primary schools in the rural town of Narok in Kenya's Rift Valley. It evaluated their awareness of key environmental issues in their local area and their knowledge about the causes, effects and solutions pertaining to these environmental issues. A descriptive research design was…

  11. Potential for mosquitoes (Diptera: Culicidae) from Florida to transmit rift valley fever virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated 8 species of mosquitoes collected in Florida to determine which of these should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America. Female mosquitoes that had fed on adult hamsters inoculated with RVFV were incubated for 7-21 d at 26°C, allowed to...

  12. CURRENT ISSUES AND CONCERNS REGARDING RIFT VALLEY FEVER, AN EMERGING VIRUS THREAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) virus is a mosquito-borne zoonotic hemorrhagic disease that causes 100% abortions in cattle, sheep, and goats and is often fatal to young animals. Though currently confined mainly to Africa this disease could be introduced into the U.S. and spread via mosquitoes at least as ...

  13. USDA, ARS, ABDRL Research on Countermeasures for Rift Valley Fever Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The United State Department of Agriculture, Agriculture Research Service has recently established research program to address countermeasures for of Rift Valley fever (RVF) virus (RVFV). The recent outbreak in Kenya, Tanzania and Somalia demonstrates the impact this virus can have on human and live...

  14. Effect of environmental temperature on the vector competence of mosquitoes for Rift Valley fever virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Environmental temperature has been shown to affect the ability of mosquitoes to transmit numerous arboviruses and for Rift Valley fever virus (RVFV) in particular. We evaluated the effect of incubation temperatures ranging from 14-26ºC on infection, dissemination, and transmission rates for Culex ta...

  15. Mosquitoes and the environment in Nile Delta villages with previous rift valley fever activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Egypt is affected by serious human and animal mosquito-borne diseases such as Rift Valley fever (RVF). We investigated how potential RVF virus mosquito vector populations are affected by environmental conditions in the Nile Delta region of Egypt by collecting mosquitoes and environmental data from t...

  16. Immunohistochemical Detection of Rift Valley Fever Virus with Non-Infectious, Recombinant Viral Protein Antibodies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV) causes re-emerging disease outbreaks and abortion storms in mature cattle, sheep, and goats, and can cause 100% mortality in young animals. The spread of this exotic, insect transmitted virus is of particular concern because of its widely recognized potential for being...

  17. New Diagnostic Tools for Detecting Rift Valley Fever (RVF) and other Arboviruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The outbreak of West Nile virus in the United Sates and the recent outbreak of Rift Valley fever (RVF) virus in East Africa have highlighted the need for validated early detection tools for arthropod-borne animal diseases. The Arthropod-Borne Animal Diseases Research Laboratory (ABADRL) has been inv...

  18. Comparison of Rift Valley fever virus replication in North American livestock and wildlife cell lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV) causes outbreaks of endemic disease across Africa and the Arabian Peninsula, resulting in high morbidity and mortality among young domestic livestock, frequent abortions in pregnant animals, and potentially severe or fatal disease in humans. The possibility of RVFV spr...

  19. Experimental infection of calves by two genetically-distinct strains of rift valley fever virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent outbreaks of Rift Valley fever in ruminant livestock, characterized by mass abortion and high mortality rates in neonates, have raised international interest in improving vaccine control strategies. Previously we developed a reliable challenge model for sheep that improves the evaluation of ...

  20. Evaluation of lamb and calf responses to Rift Valley fever MP-12 vaccination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is an important viral disease of animals and humans in Africa and the Middle East that is transmitted by mosquitoes. The disease is of concern to international agricultural and public health communities. The RVF MP-12 strain has been the most safety tested attenuated vaccine ...

  1. Utility of Antibody Avidity for Rift Valley Fever Virus Vaccine Potency and Immunogenicity Studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Disease outbreaks caused by arthropod-borne animal viruses (arboviruses) resulting in significant livestock and economic losses world-wide appear to be increasing. Rift Valley fever (RVF) virus is an important arbovirus that causes lethal disease in cattle, camels, sheep and goats in sub-Saharan Afr...

  2. Potential for Psorophora columbiae and Psorophora ciliata mosquitoes (Diptera: Culicidae) to transmit Rift Valley fever virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV) continues to pose a threat to much of the world. Unlike many arboviruses, numerous mosquito species have been associated with RVFV in nature, and many species have been demonstrated as competent vectors in the laboratory. In this study, we evaluated two field-collect...

  3. Development of a Rift Valley fever virus viremia challenge model in sheep and goats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift valley fever virus (RVFV), a member of the family Bunyaviridae, causes severe to fatal disease in newborn ruminants, as well as abortions in pregnant animals; both preventable by vaccination. Availability of a challenge model is a pre-requisite for vaccine efficacy trials. Several modes of ino...

  4. Factors Affecting the Ability of American Mosquitoes to Transmit Rift Valley Fever Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recent outbreaks of disease caused by Rift Valley fever virus (RVFV) in Kenya, Mauritania, Yemen, Tanzania, Somalia, and Madagascar indicate the potential for RVFV to cause severe disease in both humans and domestic animals and its potential to be introduced into new areas, including North Ameri...

  5. Vector Competence of Selected African Mosquito (Diptera: Culicidae) Species for Rift Valley Fever Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Outbreaks of Rift Valley fever (RVF) in Egypt, Yemen, and Saudi Arabia have indicated the potential for this disease to spread from its enzootic areas in sub-Saharan Africa. Because little is known about the potential for most African mosquito species to transmit RVF virus (RVFV), we conducted stud...

  6. Potential for North American Mosquitoes to Transmit Rift Valley Fever Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recent outbreaks of disease caused by Rift Valley fever virus (RVFV) in Kenya, Mauritania, Yemen, Tanzania, Somalia, and Madagascar indicate the potential for RVFV to cause severe disease in both humans and domestic animals and its potential to be introduced into new areas, including North Ameri...

  7. Potential for North American mosquitoes to transmit Rift Valley fever virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recent outbreaks of disease caused by Rift Valley fever virus (RVFV) in Kenya, Mauritania, Yemen, Tanzania, Somalia, and Madagascar indicate the potential for RVFV to cause severe disease in both humans and domestic animals and its potential to be introduced into new areas, possibly even North A...

  8. Mosquito host choices on livestock amplifiers of Rift Valley fever virus in Kenya

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal hosts may vary in their attraction and acceptability as components of the host location process for assessing biting rates of vectors and risk of exposure to pathogens. However, these parameters remain poorly understood for mosquito vectors of the Rift Valley fever (RVF), an arboviral disease...

  9. Rift Valley Fever Virus Control: Integration of Virus, Host and Vector Studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a disease of animals and humans that occurs in Africa and the Arabian Peninsula. It is caused by a Phlebovirus in the family Bunyaviridae. Mosquito-borne epizootics occur during years of unusually heavy rainfall. Domestic cattle, sheep and goats are highly susceptible to i...

  10. Blood Meal Analysis of Mosquitoes Involved in a Rift Valley fever Outbreak

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Rift Valley fever (RVF) is a zoonosis of domestic ruminants in Africa. Bloodfed mosquitoes collected during the 2006-2007 RVF outbreak in Kenya were analyzed to determine the virus infection status and animal source of the bloodmeals. Bloodmeals from individual mosquito abdomens were sc...

  11. Rift Valley fever risk map model and seroprevalence in selected wild ungulates and camels from Kenya

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since the first isolation of Rift Valley fever virus (RVFV) in the 1930s, there have been multiple epizootics and epidemics in animals and humans in sub-Saharan Africa. Prospective climate-based models have recently been developed that flag areas at risk of RVFV transmission in endemic regions based...

  12. One Health –One World Approaches to Detection and Control of Rift Valley Fever

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a disease of animals and humans that occurs in Africa and the Arabian Peninsula. A Phlebovirus in the family Bunyaviridae causes the disease that is transmitted by mosquitoes. Epidemics occur during years of unusually heavy rainfall that assessment models are being develop...

  13. Current Status on the Development of Operator Safe Diagnostic Tools for Rift Valley Fever

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a disease of animals and humans that occurs in Africa and the Arabian Peninsula. It is caused by a Phlebovirus in the family Bunyaviridae. Mosquito-borne epidemics occur during years of unusually heavy rainfall. Domestic cattle, sheep and goats are highly susceptible to...

  14. A Glycoprotein Subunit Vaccine Elicits a Strong Rift Valley Fever Virus Neutralizing Antibody Response in Sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV), a member of the Bunyaviridae family, is a mosquito-borne zoonotic pathogen that causes serious morbidity and mortality in livestock and humans. The recent spread of the virus beyond its traditional endemic boundaries in Africa to the Arabian Peninsula coupled with the...

  15. The Late Oligocene to Early Miocene early evolution of rifting in the southwestern part of the Roer Valley Graben

    NASA Astrophysics Data System (ADS)

    Deckers, Jef

    2016-06-01

    The Roer Valley Graben is a Mesozoic continental rift basin that was reactivated during the Late Oligocene. The study area is located in the graben area of the southwestern part of the Roer Valley Graben. Rifting initiated in the study area with the development of a large number of faults in the prerift strata. Some of these faults were rooted in preexisting zones of weakness in the Mesozoic strata. Early in the Late Oligocene, several faults died out in the study area as strain became focused upon others, some of which were able to link into several-kilometer-long systems. Within the Late Oligocene to Early Miocene northwestward prograding shallow marine syn-rift deposits, the number of active faults further decreased with time. A relatively strong decrease was observed around the Oligocene/Miocene boundary and represents a further focus of strain onto the long fault systems. Miocene extensional strain was not accommodated by further growth, but predominantly by displacements along the long fault systems. Since the Oligocene/Miocene boundary coincides with a radical change in the European intraplate stress field, the latter might have contributed significantly to the simultaneous change of fault kinematics in the study area.

  16. Evaluating spatial and temporal variations of rainfall erosivity, case of Central Rift Valley of Ethiopia

    NASA Astrophysics Data System (ADS)

    Meshesha, Derege Tsegaye; Tsunekawa, Atsushi; Tsubo, Mitsuru; Haregeweyn, Nigussie; Adgo, Enyew

    2015-02-01

    Land degradation in many Ethiopian highlands occurs mainly due to high rainfall erosivity and poor soil conservation practices. Rainfall erosivity is an indicator of the precipitation energy and ability to cause soil erosion. In Central Rift Valley (CRV) of Ethiopia, where the climate is characterized as arid and semiarid, rainfall is the main driver of soil erosion that in turn causes a serious expansion in land degradation. In order to evaluate the spatial and temporal variability of rainfall erosivity and its impact on soil erosion, long-term rainfall data (1980-2010) was used, and the monthly Fournier index (FI) and the annual modified Fournier index (MFI) were applied. Student's t test analysis was performed particularly to examine statistical significances of differences in average monthly and annual erosivity values. The result indicated that, in a similar spatial pattern with elevation and rainfall amount, average annual erosivity is also found being higher in western highlands of the valley and gradually decreased towards the east. The long-term average annual erosivity (MFI) showed a general decreasing trend in recent 10 years (2000-2010) as compared to previous 20 years (1980-1999). In most of the stations, average erosivity of main rainy months (May, June, July, and August) showed a decreasing trend, whereby some of them (about 33.3 %) are statically significant at 90 and 95 % confidence intervals but with high variation in spatial pattern of changes. The overall result of the study showed that rainfall aggression (erosivity) in the region has a general decreasing trend in the recent decade as compared to previous decades, especially in the western highlands of the valley. Hence, it implies that anthropogenic factors such as land use change being coupled with topography (steep slope) have largely contributed to increased soil erosion rate in the region.

  17. A Spatial Analysis of Rift Valley Fever Virus Seropositivity in Domestic Ruminants in Tanzania

    PubMed Central

    Sindato, Calvin; Pfeiffer, Dirk U.; Karimuribo, Esron D.; Mboera, Leonard E. G.; Rweyemamu, Mark M.; Paweska, Janusz T.

    2015-01-01

    Rift Valley fever (RVF) is an acute arthropod-borne viral zoonotic disease primarily occurring in Africa. Since RVF-like disease was reported in Tanzania in 1930, outbreaks of the disease have been reported mainly from the eastern ecosystem of the Great Rift Valley. This cross-sectional study was carried out to describe the variation in RVF virus (RVFV) seropositivity in domestic ruminants between selected villages in the eastern and western Rift Valley ecosystems in Tanzania, and identify potential risk factors. Three study villages were purposively selected from each of the two Rift Valley ecosystems. Serum samples from randomly selected domestic ruminants (n = 1,435) were tested for the presence of specific immunoglobulin G (IgG) and M (IgM), using RVF enzyme-linked immunosorbent assay methods. Mixed effects logistic regression modelling was used to investigate the association between potential risk factors and RVFV seropositivity. The overall RVFV seroprevalence (n = 1,435) in domestic ruminants was 25.8% and speciesspecific seroprevalence was 29.7%, 27.7% and 22.0% in sheep (n = 148), cattle (n = 756) and goats (n = 531), respectively. The odds of seropositivity were significantly higher in animals sampled from the villages in the eastern than those in the western Rift Valley ecosystem (OR = 1.88, CI: 1.41, 2.51; p<0.001), in animals sampled from villages with soils of good than those with soils of poor water holding capacity (OR = 1.97; 95% CI: 1.58, 3.02; p< 0.001), and in animals which had been introduced than in animals born within the herd (OR = 5.08, CI: 2.74, 9.44; p< 0.001). Compared with animals aged 1–2 years, those aged 3 and 4–5 years had 3.40 (CI: 2.49, 4.64; p< 0.001) and 3.31 (CI: 2.27, 4.82, p< 0.001) times the odds of seropositivity. The findings confirm exposure to RVFV in all the study villages, but with a higher prevalence in the study villages from the eastern Rift Valley ecosystem. PMID:26162089

  18. Serological surveillance studies confirm the Rift Valley fever virus free status in South Korea.

    PubMed

    Kim, Hyun Joo; Park, Jee-Yong; Jeoung, Hye-Young; Yeh, Jung-Yong; Cho, Yun-Sang; Choi, Jeong-Soo; Lee, Ji-Youn; Cho, In-Soo; Yoo, Han-Sang

    2015-10-01

    Rift Valley fever is a mosquito-borne zoonotic disease of domestic ruminants. This disease causes abortions in pregnant animals, and it has a high mortality rate in newborn animals. Recently, a Rift Valley fever virus (RVFV) outbreak in the Arabian Peninsula increased its potential spread to new regions worldwide. In non-endemic or disease-free countries, early detection and surveillance are important for preventing the introduction of RVFV. In this study, a serological surveillance was conducted to detect antibodies against RVFV. A total of 2382 serum samples from goats and cattle were randomly collected from nine areas in South Korea from 2011 to 2013. These samples were tested for antibodies against RVFV, using commercial ELISA kits. None of the goats and cattle were positive for antibodies against RVFV. This finding suggests that this disease is not present in South Korea, and furthermore presents the evidence of the RVFV-free status of this country. PMID:26024956

  19. Towards a better understanding of Rift Valley fever epidemiology in the south-west of the Indian Ocean

    PubMed Central

    2013-01-01

    Rift Valley fever virus (Phlebovirus, Bunyaviridae) is an arbovirus causing intermittent epizootics and sporadic epidemics primarily in East Africa. Infection causes severe and often fatal illness in young sheep, goats and cattle. Domestic animals and humans can be contaminated by close contact with infectious tissues or through mosquito infectious bites. Rift Valley fever virus was historically restricted to sub-Saharan countries. The probability of Rift Valley fever emerging in virgin areas is likely to be increasing. Its geographical range has extended over the past years. As a recent example, autochthonous cases of Rift Valley fever were recorded in 2007–2008 in Mayotte in the Indian Ocean. It has been proposed that a single infected animal that enters a naive country is sufficient to initiate a major outbreak before Rift Valley fever virus would ever be detected. Unless vaccines are available and widely used to limit its expansion, Rift Valley fever will continue to be a critical issue for human and animal health in the region of the Indian Ocean. PMID:24016237

  20. Characterisation of immune responses and protective efficacy in mice after immunisation with Rift Valley Fever virus cDNA constructs

    PubMed Central

    Lagerqvist, Nina; Näslund, Jonas; Lundkvist, Åke; Bouloy, Michèle; Ahlm, Clas; Bucht, Göran

    2009-01-01

    Background Affecting both livestock and humans, Rift Valley Fever is considered as one of the most important viral zoonoses in Africa. However, no licensed vaccines or effective treatments are yet available for human use. Naked DNA vaccines are an interesting approach since the virus is highly infectious and existing attenuated Rift Valley Fever virus vaccine strains display adverse effects in animal trials. In this study, gene-gun immunisations with cDNA encoding structural proteins of the Rift Valley Fever virus were evaluated in mice. The induced immune responses were analysed for the ability to protect mice against virus challenge. Results Immunisation with cDNA encoding the nucleocapsid protein induced strong humoral and lymphocyte proliferative immune responses, and virus neutralising antibodies were acquired after vaccination with cDNA encoding the glycoproteins. Even though complete protection was not achieved by genetic immunisation, four out of eight, and five out of eight mice vaccinated with cDNA encoding the nucleocapsid protein or the glycoproteins, respectively, displayed no clinical signs of infection after challenge. In contrast, all fourteen control animals displayed clinical manifestations of Rift Valley Fever after challenge. Conclusion The appearance of Rift Valley Fever associated clinical signs were significantly decreased among the DNA vaccinated mice and further adjustment of this strategy may result in full protection against Rift Valley Fever. PMID:19149901

  1. Potency of a thermostabilised chimpanzee adenovirus Rift Valley Fever vaccine in cattle

    PubMed Central

    Dulal, Pawan; Wright, Daniel; Ashfield, Rebecca; Hill, Adrian V.S.; Charleston, Bryan; Warimwe, George M.

    2016-01-01

    Development of safe and efficacious vaccines whose potency is unaffected by long-term storage at ambient temperature would obviate major vaccine deployment hurdles and limit wastage associated with breaks in the vaccine cold chain. Here, we evaluated the immunogenicity of a novel chimpanzee adenovirus vectored Rift Valley Fever vaccine (ChAdOx1-GnGc) in cattle, following its thermostabilisation by slow desiccation on glass fiber membranes in the non-reducing sugars trehalose and sucrose. Thermostabilised ChAdOx1-GnGc vaccine stored for 6 months at 25, 37 or 45 °C elicited comparable Rift Valley Fever virus neutralising antibody titres to those elicited by the ‘cold chain’ vaccine (stored at −80 °C throughout) at the same dose, and these were within the range associated with protection against Rift Valley Fever in cattle. The results support the use of sugar-membrane thermostabilised vaccines in target livestock species. PMID:27020712

  2. The first australopithecine 2,500 kilometres west of the Rift Valley (Chad)

    PubMed

    Brunet, M; Beauvilain, A; Coppens, Y; Heintz, E; Moutaye, A H; Pilbeam, D

    1995-11-16

    The first sites with Pliocene and Pleistocene mammals west of the Rift Valley in Central Africa in northern Chad were reported in 1959 (ref. 1), and documented the presence of mixed savannah and woodland habitats. Further sites and a probable Homo erectus cranio-facial fragment were subsequently discovered. In 1993 a survey of Pliocene and Pleistocene formations in the Borkou-Ennedi-Tibesti Province of Chad (B.E.T.) led to the discovery of 17 new sites in the region of Bahr el Ghazal (classical Arabic for River of the Gazelles) near Koro Toro. One site, KT 12 (15 degrees 58'10"N, 18 degrees 52'46"E) yielded an australopithecine mandible associated with a fauna biochronologically estimated to be 3.0-3.5 Myr old. Australopithecine species described since 1925 are known from southern Africa and from sites spread along the eastern Rift Valley from Tanzania to Ethiopia (Fig. 1). This new find from Chad, which is most similar in morphology to Australopithecus afarensis, documents the presence of an early hominid a considerable distance, 2,500 km, west of the Rift Valley. PMID:7477344

  3. REE partitioning between apatite and melt in a peralkaline volcanic suite, Kenya Rift Valley

    USGS Publications Warehouse

    Macdonald, R.; Baginski, B.; Belkin, H.E.; Dzierzanowski, P.; Jezak, L.

    2009-01-01

    Electron microprobe analyses are presented for fluorapatite phenocrysts from a benmoreite-peralkaline rhyolite volcanic suite from the Kenya Rift Valley. The rocks have previously been well characterized petrographically and their crystallization conditions are reasonably well known. The REE contents in the M site increase towards the rhyolites, with a maximum britholite component of ~35 mol.%. Chondrite-normalized REE patterns are rather flat between La and Sm and then decrease towards Yb. Sodium and Fe occupy up to 1% and 4%, respectively, of the M site. The major coupled substitution is REE3+ + Si4+ ??? Ca2+ + P5+. The substitution REE3+ + Na+ ??? 2Ca2+ has been of minor importance. The relatively large Fe contents were perhaps facilitated by the low fo2 conditions of crystallization. Zoning is ubiquitous and resulted from both fractional crystallization and magma mixing. Apatites in some rhyolites are relatively Y-depleted, perhaps reflecting crystallization from melts which had precipitated zircon. Mineral/glass (melt) ratios for two rhyolites are unusually high, with maxima at Sm (762, 1123). ?? 2008 The Mineralogical Society.

  4. Risk factors associated with Rift Valley fever epidemics in South Africa in 2008–11

    PubMed Central

    Métras, Raphaëlle; Jewell, Chris; Porphyre, Thibaud; Thompson, Peter N.; Pfeiffer, Dirk U.; Collins, Lisa M.; White, Richard G.

    2015-01-01

    Rift Valley fever (RVF) is a zoonotic and vector-borne disease, mainly present in Africa, which represents a threat to human health, animal health and production. South Africa has experienced three major RVF epidemics (1950–51, 1973–75 and 2008–11). Due to data scarcity, no previous study has quantified risk factors associated with RVF epidemics in animals in South Africa. Using the 2008–11 epidemic datasets, a retrospective longitudinal study was conducted to identify and quantify spatial and temporal environmental factors associated with RVF incidence. Cox regressions with a Besag model to account for the spatial effects were fitted to the data. Coefficients were estimated by Bayesian inference using integrated nested Laplace approximation. An increase in vegetation density was the most important risk factor until 2010. In 2010, increased temperature was the major risk factor. In 2011, after the large 2010 epidemic wave, these associations were reversed, potentially confounded by immunity in animals, probably resulting from earlier infection and vaccination. Both vegetation density and temperature should be considered together in the development of risk management strategies. However, the crucial need for improved access to data on population at risk, animal movements and vaccine use is highlighted to improve model predictions. PMID:25804974

  5. Severe Rift Valley Fever May Present with a Characteristic Clinical Syndrome

    PubMed Central

    Kahlon, Summerpal S.; Peters, Clarence J.; LeDuc, James; Muchiri, Eric M.; Muiruri, Samuel; Njenga, M. Kariuki; Breiman, Robert F.; Clinton White, A.; King, Charles H.

    2010-01-01

    Rift Valley fever (RVF) virus is an emerging pathogen that is transmitted in many regions of sub-Saharan Africa, parts of Egypt, and the Arabian peninsula. Outbreaks of RVF, like other diseases caused by hemorrhagic fever viruses, typically present in locations with very limited health resources, where initial diagnosis must be based only on history and physical examination. Although general signs and symptoms of human RVF have been documented, a specific clinical syndrome has not been described. In 2007, a Kenyan outbreak of RVF provided opportunity to assess acutely ill RVF patients and better delineate its presentation and clinical course. Our data reveal an identifiable clinical syndrome suggestive of severe RVF, characterized by fever, large-joint arthralgia, and gastrointestinal complaints and later followed by jaundice, right upper-quadrant pain, and delirium, often coinciding with hemorrhagic manifestations. Further characterization of a distinct RVF clinical syndrome will aid earlier detection of RVF outbreaks and should allow more rapid implementation of control. PMID:20207858

  6. Environmental change and Rift Valley fever in eastern Africa: projecting beyond HEALTHY FUTURES.

    PubMed

    Taylor, David; Hagenlocher, Michael; Jones, Anne E; Kienberger, Stefan; Leedale, Joseph; Morse, Andrew P

    2016-01-01

    Outbreaks of Rift Valley fever (RVF), a relatively recently emerged zoonosis endemic to large parts of sub-Saharan Africa that has the potential to spread beyond the continent, have profound health and socio-economic impacts, particularly in communities where resilience is already low. Here output from a new, dynamic disease model [the Liverpool RVF (LRVF) model], driven by downscaled, bias-corrected climate change data from an ensemble of global circulation models from the Inter-Sectoral Impact Model Intercomparison Project run according to two radiative forcing scenarios [representative concentration pathway (RCP)4.5 and RCP8.5], is combined with results of a spatial assessment of social vulnerability to the disease in eastern Africa. The combined approach allowed for analyses of spatial and temporal variations in the risk of RVF to the end of the current century. Results for both scenarios highlight the high-risk of future RVF outbreaks, including in parts of eastern Africa to date unaffected by the disease. The results also highlight the risk of spread from/to countries adjacent to the study area, and possibly farther afield, and the value of considering the geography of future projections of disease risk. Based on the results, there is a clear need to remain vigilant and to invest not only in surveillance and early warning systems, but also in addressing the socio-economic factors that underpin social vulnerability in order to mitigate, effectively, future impacts. PMID:27063733

  7. Risk factors associated with Rift Valley fever epidemics in South Africa in 2008-11.

    PubMed

    Métras, Raphaëlle; Jewell, Chris; Porphyre, Thibaud; Thompson, Peter N; Pfeiffer, Dirk U; Collins, Lisa M; White, Richard G

    2015-01-01

    Rift Valley fever (RVF) is a zoonotic and vector-borne disease, mainly present in Africa, which represents a threat to human health, animal health and production. South Africa has experienced three major RVF epidemics (1950-51, 1973-75 and 2008-11). Due to data scarcity, no previous study has quantified risk factors associated with RVF epidemics in animals in South Africa. Using the 2008-11 epidemic datasets, a retrospective longitudinal study was conducted to identify and quantify spatial and temporal environmental factors associated with RVF incidence. Cox regressions with a Besag model to account for the spatial effects were fitted to the data. Coefficients were estimated by Bayesian inference using integrated nested Laplace approximation. An increase in vegetation density was the most important risk factor until 2010. In 2010, increased temperature was the major risk factor. In 2011, after the large 2010 epidemic wave, these associations were reversed, potentially confounded by immunity in animals, probably resulting from earlier infection and vaccination. Both vegetation density and temperature should be considered together in the development of risk management strategies. However, the crucial need for improved access to data on population at risk, animal movements and vaccine use is highlighted to improve model predictions. PMID:25804974

  8. Massive sulfides in a sedimented rift valley, northern Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Davis, Earl E.; Goodfellow, Wayne D.; Bornhold, Brian D.; Adshead, John; Blaise, Bertrand; Villinger, Heiner; Le Cheminant, Gina M.

    1987-03-01

    A number of mounds each several hundred meters across and up to sixty meters high have been observed with SeaMARC II acoustic imagery and Seabeam bathymetry in the sediment-filled axial valley at the northern end of the Juan de Fuca Ridge. The mounds are located a few kilometers west of the eastern valley-bounding normal fault scarp where the local sediment fill is approximately 300 m thick. All of the mounds are believed to be of hydrothermal origin, and one is associated with anomalously high heat flow in excess of 1 W m -2. A piston core collected from that mound comprises coarse clastic sulfide units interbedded with sulfidic muds. Hydrothermal minerals present in the 2.3 m section include pyrrhotite, pyrite, marcasite, sphalerite, chalcopyrite, iss (intermediate solid solution in the Cu sbnd Fe sbnd Zn sbnd S system), chalcopyrrhotite, galena, talc, barite, and amorphous silica. Mineral fabrics of the clasts indicate that the material was precipitated at or near the sea floor by mixing of hot hydrothermal fluids with cold seawater. Low concentrations of Zn, Cu, Cd, and Ag relative to those found in unsedimented ridge hydrothermal deposits, and the presence of pyrrhotite as an early phase mineral indicates that the vent fluids have been modified by reaction with sediments beneath the mound. Rapid sedimentation in a rift valley is clearly conducive to the formation of large hydrothermal mineral deposits like those believed to be present within and beneath these mounds. The relatively impermeable sediment cover insulates the crust, inhibits groundwater recharge, promotes long-lived discharge at a restricted number of sites, provides a substrate for the efficient subsurface precipitation of minerals, and through continued sedimentation, protects surficial deposits from the corrosive effects of seawater. No reliable estimate of the bulk composition of the mounds can be made with existing data, but their size is comparable to major hydrothermal mineral deposits

  9. Development of an Upper Cambrian rimmed shelf along the Mississippi Valley Graben, Reelfoot Rift, and the southeastern Ozarks, southern Missouri

    SciTech Connect

    Palmer, J.R. . Dept. of Natural Resources)

    1993-03-01

    The paleogeographic distribution of intrashelf basin shales and limestones in the Bonneterre (Dresbachian) and Davis (Franconian) Formations, and associated data, suggests that rimmed shelf conditions separated the central Missouri part of the shelf from the Mississippi Valley Graben (MVG) of the Reelfoot Rift to the southeast. Middle Dresbachian rocks of the intrashelf basin area, predominantly limestones, indicate a discontinuous carbonate shelf rim. The succeeding widespread shales of the Franconian intrashelf basin indicate that a continuous rim had developed. The margin of the shelf rim is preserved in part of the 4,700-ft-thick Upper Cambrian succession along the northwest margin of the Mississippi Valley Graben (MVG) of the Reelfoot Rift. Equivalent rocks within the MVG are dominantly dark shales (1,600+ ft thick). The Amoco Spence test well penetrated the rim succession on the northwest margin of the MVG. At least 11 large-scale transgressive-regressive (T-R) carbonate cycles (120--600 ft thick) have been defined in this well; 7 cycles are equivalent to the Bonneterre and Davis Formations. These latter cycles have shaly limestone, or limestone at the base, and grade upward to dolostone or coarsely crystalline dolostone, which are interpreted to be shallowing-upward, bank margin-peritidal carbonates. Northwest of the rim margin and on the southeast side of the St. Francois Mountains, rocks equivalent to the rim succession consist of a series of ramp to platform cycles made up of dolostones and local limestones. Many carbonate shelves on passive margins are rimmed. The development of this Upper Cambrian rimmed shelf along the northwest margin of the MVG suggests that failed rifts can also localized such rims.

  10. Ethiopian Central Rift Valley basin hydrologic modelling using HEC-HMS and ArcSWAT

    NASA Astrophysics Data System (ADS)

    Pascual-Ferrer, Jordi; Candela, Lucila; Pérez-Foguet, Agustí

    2013-04-01

    An Integrated Water Resources Management (IWRM) shall be applied to achieve a sustainable development, to increase population incomes without affecting lives of those who are highly dependent on the environment. First step should be to understand water dynamics at basin level, starting by modeling the basin water resources. For model implementation, a large number of data and parameters are required, but those are not always available, especially in some developing countries where different sources may have different data, there is lack of information on data collection, etc. The Ethiopian Central Rift Valley (CRV) is an endorheic basin covering an area of approximately 10,000 km2. For the period 1996-2005, the average annual volume of rainfall accounted for 9.1 Mm3, and evapotranspiration for 8 Mm3 (Jansen et al., 2007). From the environmental point of view, basin ecosystems are endangered due to human activities. Also, poverty is widespread all over the basin, with population mainly living from agriculture on a subsistence economy. Hence, there is an urgent need to set an IWRM, but datasets required for water dynamics simulation are not too reliable. In order to reduce uncertainty of numerical simulation, two semi-distributed open software hydrologic models were implemented: HEC-HMS and ArcSWAT. HEC-HMS was developed by the United States Army Corps of Engineers (USACoE) Hydrologic Engineering Center (HEC) to run precipitation-runoff simulations for a variety of applications in dendritic watershed systems. ArcSWAT includes the SWAT (Soil and Water Assessment Tool, Arnold et al., 1998) model developed for the USDA Agricultural Research Service into ArcGIS (ESRI®). SWAT was developed to assess the impact of land management practices on large complex watersheds with varying soils, land use and management conditions over long periods of time (Neitsch et al., 2005). According to this, ArcSWAT would be the best option for IWRM implementation in the basin. However

  11. Mosquitoes and the Environment in Nile Delta Villages with Previous Rift Valley Fever Activity.

    PubMed

    Zayed, Abdelbaset B; Britch, Seth C; Soliman, Mohamed I; Linthicum, Kenneth J

    2015-06-01

    Egypt is affected by serious human and animal mosquito-borne diseases such as Rift Valley fever (RVF). We investigated how potential RVF virus mosquito vector populations are affected by environmental conditions in the Nile Delta region of Egypt by collecting mosquitoes and environmental data from 3 key governorates before and after 2012 seasonal flooding. We found that environmental effects varied among species, life stages, pre- and postflood groupings, and geographic populations of the same species, and that mosquito community composition could change after flooding. Our study provides preliminary data for modeling mosquitoes and mosquito-borne diseases in the Nile Delta region. PMID:26181689

  12. Economic Assessment of Zoonotic Diseases: An Illustrative Study of Rift Valley Fever in the United States.

    PubMed

    Pendell, D L; Lusk, J L; Marsh, T L; Coble, K H; Szmania, S C

    2016-04-01

    This study evaluates the economic consequences of a Rift Valley Fever outbreak, a virus that spreads from livestock to humans, often through mosquitoes. Developing a 'one health' economic framework, economic impacts on agricultural producers and consumers, government costs of response, costs and disruptions to non-agricultural activities in the epidemiologically impacted region, and human health costs (morbidity and mortality) are estimated. We find the agricultural firms bear most of the negative economic impacts, followed by regional non-agricultural firms, human health and government. Further, consumers of agricultural products benefit from small outbreaks due to bans on agricultural exports. PMID:25052324

  13. Detection of Rift Valley fever viral activity in Kenya by satellite remote sensing imagery

    NASA Technical Reports Server (NTRS)

    Linthicum, Kenneth J.; Bailey, Charles L.; Davies, F. Glyn; Tucker, Compton J.

    1987-01-01

    Data from the advanced very high resolution radiometer on board the National Oceanic and Atmospheric Administration's polar-orbiting meteorological satellites have been used to infer ecological parameters associated with Rift Valley fever (RVF) viral activity in Kenya. An indicator of potential viral activity was produced from satellite data for two different ecological regions in Kenya, where RVF is enzootic. The correlation between the satellite-derived green vegetation index and the ecological parameters associated with RVF virus suggested that satellite data may become a forecasting tool for RVF in Kenya and, perhaps, in other areas of sub-Saharan Africa.

  14. Rift Valley fever virus infection induces activation of the NLRP3 inflammasome

    PubMed Central

    Ermler, Megan E.; Traylor, Zachary; Patel, Krupen; Schattgen, Stefan A.; Vanaja, Sivapriya K.; Fitzgerald, Katherine A.; Hise, Amy G.

    2014-01-01

    Inflammasome activation is gaining recognition as an important mechanism for protection during viral infection. Here, we investigate whether Rift Valley fever virus, a negative-strand RNA virus, can induce inflammasome responses and IL-1β processing in immune cells. We have determined that RVFV induces NLRP3 inflammasome activation in murine dendritic cells, and that this process is dependent upon ASC and caspase-1. Furthermore, absence of the cellular RNA helicase adaptor protein MAVS/IPS-1 significantly reduces extracellular IL-1β during infection. Finally, direct imaging using confocal microscopy shows that the MAVS protein co-localizes with NLRP3 in the cytoplasm of RVFV infected cells. PMID:24418550

  15. Detection of Rift Valley fever viral activity in Kenya by satellite remote sensing imagery.

    PubMed

    Linthicum, K J; Bailey, C L; Davies, F G; Tucker, C J

    1987-03-27

    Data from the advanced very high resolution radiometer on board the National Oceanic and Atmospheric Administration's polar-orbiting meteorological satellites have been used to infer ecological parameters associated with Rift Valley fever (RVF) viral activity in Kenya. An indicator of potential viral activity was produced from satellite data for two different ecological regions in Kenya, where RVF is enzootic. The correlation between the satellite-derived green vegetation index and the ecological parameters associated with RVF virus suggested that satellite data may become a forecasting tool for RVF in Kenya and, perhaps, in other areas of sub-Saharan Africa. PMID:3823909

  16. Countermeasure development for Rift Valley fever: deletion, modification or targeting of major virulence factor NSs

    PubMed Central

    Lihoradova, Olga; Ikegami, Tetsuro

    2014-01-01

    Rift Valley fever (RVF) is a mosquito-borne zoonotic disease characterized by a high rate of abortion in ruminants, and febrile illness, hemorrhagic fever, retinitis and encephalitis in humans. RVF is caused by the RVF virus (RVFV), belonging to the genus Phlebovirus of the family Bunyaviridae. RVFV encodes a major virulence factor, NSs, which is dispensable for viral replication, yet required for evasion of host innate immune responses. RVFV NSs inhibits host gene upregulation at the transcriptional level, while promoting viral translation in the cytoplasm. In this article, we summarize the virology and pathology of RVF, and countermeasure development for RVF, with emphasis on NSs function and applications. PMID:24910709

  17. The Epidemiology of Rift Valley Fever in Mayotte: Insights and Perspectives from 11 Years of Data.

    PubMed

    Métras, Raphaëlle; Cavalerie, Lisa; Dommergues, Laure; Mérot, Philippe; Edmunds, W John; Keeling, Matt J; Cêtre-Sossah, Catherine; Cardinale, Eric

    2016-06-01

    Rift Valley fever (RVF) is a zoonotic arboviral disease that is a threat to human health, animal health and production, mainly in Sub-Saharan Africa. RVF virus dynamics have been poorly studied due to data scarcity. On the island of Mayotte in the Indian Ocean, off the Southeastern African coast, RVF has been present since at least 2004. Several retrospective and prospective serological surveys in livestock have been conducted over eleven years (2004-15). These data are collated and presented here. Temporal patterns of seroprevalence were plotted against time, as well as age-stratified seroprevalence. Results suggest that RVF was already present in 2004-07. An epidemic occurred between 2008 and 2010, with IgG and IgM peak annual prevalences of 36% in 2008-09 (N = 142, n = 51, 95% CI [17-55]) and 41% (N = 96, n = 39, 95% CI [25-56]), respectively. The virus seems to be circulating at a low level since 2011, causing few new infections. In 2015, about 95% of the livestock population was susceptible (IgG annual prevalence was 6% (N = 584, n = 29, 95% CI [3-10])). Monthly rainfall varied a lot (2-540mm), whilst average temperature remained high with little variation (about 25-30°C). This large dataset collected on an insular territory for more than 10 years, suggesting a past epidemic and a current inter-epidemic period, represents a unique opportunity to study RVF dynamics. Further data collection and modelling work may be used to test different scenarios of animal imports and rainfall pattern that could explain the observed epidemiological pattern and estimate the likelihood of a potential re-emergence. PMID:27331402

  18. Perceived risk factors and risk pathways of Rift Valley fever in cattle in Ijara district, Kenya.

    PubMed

    Owange, Nelson O; Ogara, William O; Kasiiti, Jacqueline; Gathura, Peter B; Okuthe, Sam; Sang, Rosemary; Affognon, Hippolyte; Onyango-Ouma, Washington; Landmann, Tobias T O; Mbabu, Murithi

    2014-01-01

    Ijara district in Kenya was one of the hotspots of Rift Valley fever (RVF) during the 2006/2007 outbreak, which led to human and animal deaths causing major economic losses. The main constraint for the control and prevention of RVF is inadequate knowledge of the risk factors for its occurrence and maintenance. This study was aimed at understanding the perceived risk factors and risk pathways of RVF in cattle in Ijara to enable the development of improved community-based disease surveillance, prediction, control and prevention. A cross-sectional study was carried out from September 2012 to June 2013. Thirty-one key informant interviews were conducted with relevant stakeholders to determine the local pastoralists' understanding of risk factors and risk pathways of RVF in cattle in Ijara district. All the key informants perceived the presence of high numbers of mosquitoes and large numbers of cattle to be the most important risk factors contributing to the occurrence of RVF in cattle in Ijara. Key informants classified high rainfall as the most important (12/31) to an important (19/31) risk factor. The main risk pathways were infected mosquitoes that bite cattle whilst grazing and at watering points as well as close contact between domestic animals and wildlife. The likelihood of contamination of the environment as a result of poor handling of carcasses and aborted foetuses during RVF outbreaks was not considered an important pathway. There is therefore a need to conduct regular participatory community awareness sessions on handling of animal carcasses in terms of preparedness, prevention and control of any possible RVF epizootics. Additionally, monitoring of environmental conditions to detect enhanced rainfall and flooding should be prioritised for preparedness. PMID:25686079

  19. Single-Molecule FISH Reveals Non-selective Packaging of Rift Valley Fever Virus Genome Segments

    PubMed Central

    Wichgers Schreur, Paul J.; Kortekaas, Jeroen

    2016-01-01

    The bunyavirus genome comprises a small (S), medium (M), and large (L) RNA segment of negative polarity. Although genome segmentation confers evolutionary advantages by enabling genome reassortment events with related viruses, genome segmentation also complicates genome replication and packaging. Accumulating evidence suggests that genomes of viruses with eight or more genome segments are incorporated into virions by highly selective processes. Remarkably, little is known about the genome packaging process of the tri-segmented bunyaviruses. Here, we evaluated, by single-molecule RNA fluorescence in situ hybridization (FISH), the intracellular spatio-temporal distribution and replication kinetics of the Rift Valley fever virus (RVFV) genome and determined the segment composition of mature virions. The results reveal that the RVFV genome segments start to replicate near the site of infection before spreading and replicating throughout the cytoplasm followed by translocation to the virion assembly site at the Golgi network. Despite the average intracellular S, M and L genome segments approached a 1:1:1 ratio, major differences in genome segment ratios were observed among cells. We also observed a significant amount of cells lacking evidence of M-segment replication. Analysis of two-segmented replicons and four-segmented viruses subsequently confirmed the previous notion that Golgi recruitment is mediated by the Gn glycoprotein. The absence of colocalization of the different segments in the cytoplasm and the successful rescue of a tri-segmented variant with a codon shuffled M-segment suggested that inter-segment interactions are unlikely to drive the copackaging of the different segments into a single virion. The latter was confirmed by direct visualization of RNPs inside mature virions which showed that the majority of virions lack one or more genome segments. Altogether, this study suggests that RVFV genome packaging is a non-selective process. PMID:27548280

  20. Rift Valley Fever Virus Strain MP-12 Enters Mammalian Host Cells via Caveola-Mediated Endocytosis

    PubMed Central

    Harmon, Brooke; Schudel, Benjamin R.; Maar, Dianna; Kozina, Carol; Ikegami, Tetsuro; Tseng, Chien-Te Kent

    2012-01-01

    Rift Valley fever virus (RVFV) is a zoonotic pathogen capable of causing serious morbidity and mortality in both humans and livestock. The lack of efficient countermeasure strategies, the potential for dispersion into new regions, and the pathogenesis in humans and livestock make RVFV a serious public health concern. The receptors, cellular factors, and entry pathways used by RVFV and other members of the family Bunyaviridae remain largely uncharacterized. Here we provide evidence that RVFV strain MP-12 uses dynamin-dependent caveola-mediated endocytosis for cell entry. Caveolae are lipid raft domains composed of caveolin (the main structural component), cholesterol, and sphingolipids. Caveola-mediated endocytosis is responsible for the uptake of a wide variety of host ligands, as well as bacteria, bacterial toxins, and a number of viruses. To determine the cellular entry mechanism of RVFV, we used small-molecule inhibitors, RNA interference (RNAi), and dominant negative (DN) protein expression to inhibit the major mammalian cell endocytic pathways. Inhibitors and RNAi specific for macropinocytosis and clathrin-mediated endocytosis had no effect on RVFV infection. In contrast, inhibitors of caveola-mediated endocytosis, and RNAi targeted to caveolin-1 and dynamin, drastically reduced RVFV infection in multiple cell lines. Expression of DN caveolin-1 also reduced RVFV infection significantly, while expression of DN EPS15, a protein required for the assembly of clathrin-coated pits, and DN PAK-1, an obligate mediator of macropinocytosis, had no significant impact on RVFV infection. These results together suggest that the primary mechanism of RVFV MP-12 uptake is dynamin-dependent, caveolin-1-mediated endocytosis. PMID:22993156

  1. The Epidemiology of Rift Valley Fever in Mayotte: Insights and Perspectives from 11 Years of Data

    PubMed Central

    Métras, Raphaëlle; Cavalerie, Lisa; Dommergues, Laure; Mérot, Philippe; Edmunds, W. John; Keeling, Matt J.; Cêtre-Sossah, Catherine; Cardinale, Eric

    2016-01-01

    Rift Valley fever (RVF) is a zoonotic arboviral disease that is a threat to human health, animal health and production, mainly in Sub-Saharan Africa. RVF virus dynamics have been poorly studied due to data scarcity. On the island of Mayotte in the Indian Ocean, off the Southeastern African coast, RVF has been present since at least 2004. Several retrospective and prospective serological surveys in livestock have been conducted over eleven years (2004–15). These data are collated and presented here. Temporal patterns of seroprevalence were plotted against time, as well as age-stratified seroprevalence. Results suggest that RVF was already present in 2004–07. An epidemic occurred between 2008 and 2010, with IgG and IgM peak annual prevalences of 36% in 2008–09 (N = 142, n = 51, 95% CI [17–55]) and 41% (N = 96, n = 39, 95% CI [25–56]), respectively. The virus seems to be circulating at a low level since 2011, causing few new infections. In 2015, about 95% of the livestock population was susceptible (IgG annual prevalence was 6% (N = 584, n = 29, 95% CI [3–10])). Monthly rainfall varied a lot (2–540mm), whilst average temperature remained high with little variation (about 25–30°C). This large dataset collected on an insular territory for more than 10 years, suggesting a past epidemic and a current inter-epidemic period, represents a unique opportunity to study RVF dynamics. Further data collection and modelling work may be used to test different scenarios of animal imports and rainfall pattern that could explain the observed epidemiological pattern and estimate the likelihood of a potential re-emergence. PMID:27331402

  2. Spatial variability of mountain stream dynamics along the Ethiopian Rift Valley escarpment

    NASA Astrophysics Data System (ADS)

    Asfaha, Tesfaalem-Ghebreyohannes; Frankl, Amaury; Zenebe, Amanuel; Haile, Mitiku; Nyssen, Jan

    2014-05-01

    Changes in hydrogeomorphic characteristics of mountain streams are generally deemed to be controlled mainly by land use/cover changes and rainfall variability. This study investigates the spatial variability of peak discharge in relation to land cover, rainfall and topographic variables in eleven catchments of the Ethiopian Rift Valley escarpment (average slope gradient = 48% (± 13%). Rapid deforestation of the escarpment in the second half of the 20th century resulted in the occurrence of strong flash floods, transporting large amounts of discharge and sediment to the lower graben bottom. Due to integrated reforestation interventions as of the 1980s, many of these catchments do show improvement in vegetation cover at various degrees. Daily rainfall was measured using seven non-recording rain gauges, while peak stage discharges were measured after floods using crest stage gauges installed at eleven stream reaches. Peak discharges were calculated using the Manning's equation. Daily area-weighted rainfall was computed for each catchment using the Thiessen Polygon method. To estimate the vegetation cover of each catchment, the Normalized Difference Vegetation Index was calculated from Landsat TM imagery (mean = 0.14 ± 0.05). In the rainy season of 2012, there was a positive correlation between daily rainfall and peak discharge in each of the monitored catchments. In a multiple linear regression analysis (R² = 0.83; P<0.01), average daily peak discharge in all rivers was positively related with rainfall depth and catchment size and negatively with vegetation cover (as represented by average NDVI values). Average slope gradient of the catchments and Gravelius's compactness index did not show a statistically significant relation with peak discharge. This study shows that though the average vegetation cover of the catchments is still relatively low, differences in vegetation cover, together with rainfall variability plays a determining role in the amount of peak

  3. Single-Molecule FISH Reveals Non-selective Packaging of Rift Valley Fever Virus Genome Segments.

    PubMed

    Wichgers Schreur, Paul J; Kortekaas, Jeroen

    2016-08-01

    The bunyavirus genome comprises a small (S), medium (M), and large (L) RNA segment of negative polarity. Although genome segmentation confers evolutionary advantages by enabling genome reassortment events with related viruses, genome segmentation also complicates genome replication and packaging. Accumulating evidence suggests that genomes of viruses with eight or more genome segments are incorporated into virions by highly selective processes. Remarkably, little is known about the genome packaging process of the tri-segmented bunyaviruses. Here, we evaluated, by single-molecule RNA fluorescence in situ hybridization (FISH), the intracellular spatio-temporal distribution and replication kinetics of the Rift Valley fever virus (RVFV) genome and determined the segment composition of mature virions. The results reveal that the RVFV genome segments start to replicate near the site of infection before spreading and replicating throughout the cytoplasm followed by translocation to the virion assembly site at the Golgi network. Despite the average intracellular S, M and L genome segments approached a 1:1:1 ratio, major differences in genome segment ratios were observed among cells. We also observed a significant amount of cells lacking evidence of M-segment replication. Analysis of two-segmented replicons and four-segmented viruses subsequently confirmed the previous notion that Golgi recruitment is mediated by the Gn glycoprotein. The absence of colocalization of the different segments in the cytoplasm and the successful rescue of a tri-segmented variant with a codon shuffled M-segment suggested that inter-segment interactions are unlikely to drive the copackaging of the different segments into a single virion. The latter was confirmed by direct visualization of RNPs inside mature virions which showed that the majority of virions lack one or more genome segments. Altogether, this study suggests that RVFV genome packaging is a non-selective process. PMID:27548280

  4. Rift Valley fever virus (Bunyaviridae: Phlebovirus): an update on pathogenesis, molecular epidemiology, vectors, diagnostics and prevention

    PubMed Central

    Pepin, Michel; Bouloy, Michèle; Bird, Brian H.; Kemp, Alan; Paweska, Janusz

    2010-01-01

    Rift Valley fever (RVF) virus is an arbovirus in the Bunyaviridae family that, from phylogenetic analysis, appears to have first emerged in the mid-19th century and was only identified at the begininning of the 1930s in the Rift Valley region of Kenya. Despite being an arbovirus with a relatively simple but temporally and geographically stable genome, this zoonotic virus has already demonstrated a real capacity for emerging in new territories, as exemplified by the outbreaks in Egypt (1977), Western Africa (1988) and the Arabian Peninsula (2000), or for re-emerging after long periods of silence as observed very recently in Kenya and South Africa. The presence of competent vectors in countries previously free of RVF, the high viral titres in viraemic animals and the global changes in climate, travel and trade all contribute to make this virus a threat that must not be neglected as the consequences of RVF are dramatic, both for human and animal health. In this review, we present the latest advances in RVF virus research. In spite of this renewed interest, aspects of the epidemiology of RVF virus are still not fully understood and safe, effective vaccines are still not freely available for protecting humans and livestock against the dramatic consequences of this virus. PMID:21188836

  5. Correlative Gene Expression to Protective Seroconversion in Rift Valley Fever Vaccinates.

    PubMed

    Laughlin, Richard C; Drake, Kenneth L; Morrill, John C; Adams, L Garry

    2016-01-01

    Rift Valley fever Virus (RVFV), a negative-stranded RNA virus, is the etiological agent of the vector-borne zoonotic disease, Rift Valley fever (RVF). In both humans and livestock, protective immunity can be achieved through vaccination. Earlier and more recent vaccine trials in cattle and sheep demonstrated a strong neutralizing antibody and total IgG response induced by the RVF vaccine, authentic recombinant MP-12 (arMP-12). From previous work, protective immunity in sheep and cattle vaccinates normally occurs from 7 to 21 days after inoculation with arMP-12. While the serology and protective response induced by arMP-12 has been studied, little attention has been paid to the underlying molecular and genetic events occurring prior to the serologic immune response. To address this, we isolated RNA from whole blood of vaccinated calves over a time course of 21 days before and after vaccination with arMP-12. The time course RNAs were sequenced by RNASeq and bioinformatically analyzed. Our results revealed time-dependent activation or repression of numerous gene ontologies and pathways related to the vaccine induced immune response and its regulation. Additional bioinformatic analyses identified a correlative relationship between specific host immune response genes and protective immunity prior to the detection of protective serum neutralizing antibody responses. These results contribute an important proof of concept for identifying molecular and genetic components underlying the immune response to RVF vaccination and protection prior to serologic detection. PMID:26783758

  6. Correlative Gene Expression to Protective Seroconversion in Rift Valley Fever Vaccinates

    PubMed Central

    Laughlin, Richard C.; Drake, Kenneth L.; Morrill, John C.; Adams, L. Garry

    2016-01-01

    Rift Valley fever Virus (RVFV), a negative-stranded RNA virus, is the etiological agent of the vector-borne zoonotic disease, Rift Valley fever (RVF). In both humans and livestock, protective immunity can be achieved through vaccination. Earlier and more recent vaccine trials in cattle and sheep demonstrated a strong neutralizing antibody and total IgG response induced by the RVF vaccine, authentic recombinant MP-12 (arMP-12). From previous work, protective immunity in sheep and cattle vaccinates normally occurs from 7 to 21 days after inoculation with arMP-12. While the serology and protective response induced by arMP-12 has been studied, little attention has been paid to the underlying molecular and genetic events occurring prior to the serologic immune response. To address this, we isolated RNA from whole blood of vaccinated calves over a time course of 21 days before and after vaccination with arMP-12. The time course RNAs were sequenced by RNASeq and bioinformatically analyzed. Our results revealed time-dependent activation or repression of numerous gene ontologies and pathways related to the vaccine induced immune response and its regulation. Additional bioinformatic analyses identified a correlative relationship between specific host immune response genes and protective immunity prior to the detection of protective serum neutralizing antibody responses. These results contribute an important proof of concept for identifying molecular and genetic components underlying the immune response to RVF vaccination and protection prior to serologic detection. PMID:26783758

  7. Rift Valley fever virus NSs protein functions and the similarity to other bunyavirus NSs proteins.

    PubMed

    Ly, Hoai J; Ikegami, Tetsuro

    2016-01-01

    Rift Valley fever is a mosquito-borne zoonotic disease that affects both ruminants and humans. The nonstructural (NS) protein, which is a major virulence factor for Rift Valley fever virus (RVFV), is encoded on the S-segment. Through the cullin 1-Skp1-Fbox E3 ligase complex, the NSs protein promotes the degradation of at least two host proteins, the TFIIH p62 and the PKR proteins. NSs protein bridges the Fbox protein with subsequent substrates, and facilitates the transfer of ubiquitin. The SAP30-YY1 complex also bridges the NSs protein with chromatin DNA, affecting cohesion and segregation of chromatin DNA as well as the activation of interferon-β promoter. The presence of NSs filaments in the nucleus induces DNA damage responses and causes cell-cycle arrest, p53 activation, and apoptosis. Despite the fact that NSs proteins have poor amino acid similarity among bunyaviruses, the strategy utilized to hijack host cells are similar. This review will provide and summarize an update of recent findings pertaining to the biological functions of the NSs protein of RVFV as well as the differences from those of other bunyaviruses. PMID:27368371

  8. Antigenic and genetic relationships among Rift Valley fever virus and other selected members of the genus Phlebovirus (Bunyaviridae).

    PubMed

    Xu, Fangling; Liu, Dongying; Nunes, Marcio R T; DA Rosa, Amelia P A Travassos; Tesh, Robert B; Xiao, Shu-Yuan

    2007-06-01

    Preliminary serologic data indicated that two South American phleboviruses (Belterra virus [BELTV] and Icoaraci virus [ICOV]) may be related to Rift Valley fever virus (RVFV), an African phlebovirus that causes severe hepatitis and hemorrhagic fever in humans. To further define this relationship and to investigate the underlying genetic basis, comparative serologic and genetic sequence analyses were performed with RVFV and five other New World phleboviruses (ICOV, BELTV, Salobo virus, Joa virus, and Frijoles virus). Serologically, a one-way cross reaction was confirmed between antibodies against these New World viruses and RVFV antigen. In contrast, phylogenetic analysis demonstrated clear separation of these viruses from RVFV, into distinct phylogenies, based on sequences of the small, medium, and large RNA segments. PMID:17556635

  9. Using remote sensing, ecological niche modeling, and Geographic Information Systems for Rift Valley fever risk assessment in the United States

    NASA Astrophysics Data System (ADS)

    Tedrow, Christine Atkins

    transmission to humans. Maps delineating the geographic areas in Virginia with highest risk for RVF establishment in mosquito populations and RVF disease transmission to human populations were generated in a GIS using human, domestic animal, and white-tailed deer population estimates and the MaxEnt potential RVF competent vector species distribution prediction. The candidate RVF competent vector predicted distribution and RVF risk maps presented in this study can help vector control agencies and public health officials focus Rift Valley fever surveillance efforts in geographic areas with large co-located populations of potential RVF competent vectors and human, domestic animal, and wildlife hosts. Keywords. Rift Valley fever, risk assessment, Ecological Niche Modeling, MaxEnt, Geographic Information System, remote sensing, Pearson's Product-Moment Correlation Coefficient, vectors, mosquito distribution, mosquito density, mosquito surveillance, United States, Virginia, domestic animals, white-tailed deer, ArcGIS

  10. Investigation of rifting processes in the Rio Grande Rift using data from unusually large earthquake swarms

    SciTech Connect

    Sanford, A.; Balch, R.; House, L.; Hartse, H.

    1995-12-01

    San Acacia Swarm in the Rio Grande Rift. Because the Rio Grande rift is one of the best seismically instrumented rift zones in the world, studying its seismicity provides an exceptional opportunity to explore the active tectonic processes within continental rifts. We have been studying earthquake swarms recorded near Socorro in an effort to link seismicity directly to the rifting process. For FY94, our research has focused on the San Acacia swarm, which occurred 25 km north of Socorro, New Mexico, along the accommodation zone between the Albuquerque-Belen and Socorro basins of the central Rio Grande rift. The swarm commenced on 25 February 1983, had a magnitude 4.2 main shock on 2 March and ended on 17 March, 1983.

  11. The Salton Seismic Imaging Project: Tomographic characterization of a sediment-filled rift valley and adjacent ranges, southern California

    NASA Astrophysics Data System (ADS)

    Davenport, K.; Hole, J. A.; Stock, J. M.; Fuis, G. S.; Carrick, E.; Tikoff, B.

    2011-12-01

    The Salton Trough in Southern California represents the northernmost rift of the Gulf of California extensional system. Relative motion between the Pacific and North American plates is accommodated by continental rifting in step-over zones between the San Andreas, Imperial, and Cerro Prieto transform faults. Rapid sedimentation from the Colorado River has isolated the trough from the southern portion of the Gulf of California, progressively filling the subsiding rift basin. Based on data from previous seismic surveys, the pre-existing continent has ruptured completely, and a new ~22 km thick crust has been created entirely by sedimentation overlying rift-related magmatism. The MARGINS, EarthScope, and USGS-funded Salton Seismic Imaging Project (SSIP) was designed to investigate the nature of this new crust, the ongoing process of continental rifting, and associated earthquake hazards. SSIP, acquired in March 2011, comprises 7 lines of onshore seismic refraction / wide-angle reflection data, 2 lines of refraction / reflection data in the Salton Sea, and a line of broadband stations. This presentation focuses on the refraction / wide-angle reflection line across the Imperial Valley, extending ~220 km across California from Otay Mesa, near Tijuana, to the Colorado River. The data from this line includes seventeen 100-160 kg explosive shots and receivers at 100 m spacing across the Imperial Valley to constrain the structure of the Salton Trough rift basin, including the Imperial Fault. Eight larger shots (600-920 kg) at 20-35 km spacing and receivers at 200-500 m spacing extend the line across the Peninsular Ranges and the Chocolate Mountains. These data will contrast the structure of the rift to that of the surrounding crust and provide constraints on whole-crust and uppermost mantle structure. Preliminary work has included tomographic inversion of first-arrival travel times across the Valley, emphasizing a minimum-structure approach to create a velocity model of the

  12. Assessment and recommendations for two sites with active and potential aquaculture production in Rift Valley and Coast Provinces, Kenya

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Kenya has a long history of local fish consumption. The population in the Lake Victoria area (Rift Valley Province) Northwest of Nairobi and coastal communities (Coast Province) have historically included fish in their diet. Migration from villages to urban areas and increasing commerce has created ...

  13. The Example of Eastern Africa: the dynamic of Rift Valley fever and tools for monitoring virus activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever is a mosquito-borne viral zoonosis that primarily affects animals but also has the capacity to infect humans. Outbreaks of this disease in eastern Africa are closely associated with periods of heavy rainfall and forecasting models and early warning systems have been developed to en...

  14. Factors Related to the Motivation of Extension Agents in Kenya's Rift Valley Province. Summary of Research 76.

    ERIC Educational Resources Information Center

    Mwangi, John G.; McCaslin, N. L.

    Job satisfaction factors related to motivation of a random sample of 325 agents in Kenya's extension service in the Rift Valley Province were identified. Data were collected using a group-administered, closed-ended, forced-choice questionnaire with 105 job satisfaction, 10 motivational, and 10 personal characteristics items between January and…

  15. Understanding the spatial and temporal distribution of potential mosquito vectors of Rift Valley fever in the U.S.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever (RVF) is a mosquito-borne zoonotic hemorrhagic viral disease confined primarily to sub-Saharan Africa. In RVF endemic regions human and livestock populations suffer prominent health and economic impacts during RVF outbreaks. RVF virus is listed as an overlap Select Agent by both ...

  16. Development of a Rift Valley fever real-time RT-PCR assay that can detect all three genome segments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Outbreaks of Rift Valley fever in Kenya, Madagascar, Mauritania, and South Africa had devastating effects on livestock and human health. In addition, this disease is a food security issue for endemic countries. There is growing concern for the potential introduction of RVF into non-endemic countries...

  17. Prediction, Assessment of the Rift Valley fever Activity in East and Southern Africa 2006 - 2008 and Possible Vector Control Strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Historical outbreaks of Rift Valley fever (RVF) since the early 1950s have been associated with cyclical patterns of the El Nino/Southern Oscillation (ENSO) phenomenon which results in elevated and widespread rainfall over the RVF endemic areas of Africa. Using satellite measurements of global and ...

  18. Efficacy of a recombinant Rift Valley fever virus MP-12 with NSm deletion as a vaccine candidate in sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV), a mosquito-borne virus in the Bunyaviridae family and Phlebovirus genus, causes RVF, a disease of ruminants and man, endemic in Sub-Saharan African countries. However, outbreaks in Yemen and Saudi Arabia demonstrate the ability for RVFV to spread into virgin territory...

  19. Comparison of Rift Valley fever virus and MP-12 replication in domestic livestock and North American wildlife cell lines.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV) is a mosquito-transmitted pathogen that primarily affects livestock, but can also cause mild to fatal disease in humans. Currently, there is no approved vaccine for use in the United States if it were introduced. Domestic goats, sheep and cattle are susceptible hosts ...

  20. Forecasting the Temporal and Spatial Distribution of a Rift Valley fever Outbreak in East Africa: 2006-2007

    Technology Transfer Automated Retrieval System (TEKTRAN)

    El Niño/Southern Oscillation (ENSO) related climate anomalies have been shown to have a direct impact on Rift Valley fever (RVF) disease outbreaks. Knowledge of the links between ENSO driven climate anomalies and RVF can allow us to provide improved long range forecasts of an epidemic or epizootic. ...

  1. A Spatially Explicit Degree-day Model of Rift Valley Fever Transmission Risk in the Continental United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A degree-day model was used to assess the risk of Rift Valley Fever (RVF) transmission within five target states in the continental United States: California, Minnesota, Nebraska, New York, and Texas. Each state was evaluated on a 10-km grid using the average of historical daily temperature extreme...

  2. Prediction, Assessment of the Rift Valley Fever Activity in East and Southern Africa 2006 - 2008 and Possible Vector Control Strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Historical episodic outbreaks of Rift Valley fever (RVF) since the early 1950s have been associated with cyclical patterns (El Niño and La Niña) of El Niño Southern Oscillation (ENSO) phenomenon which results in elevated and widespread rainfall over the RVF endemic areas of Africa. Using satellite ...

  3. A Haploid Genetic Screen Identifies Heparan Sulfate Proteoglycans Supporting Rift Valley Fever Virus Infection

    PubMed Central

    Riblett, Amber M.; Blomen, Vincent A.; Jae, Lucas T.; Altamura, Louis A.; Doms, Robert W.; Brummelkamp, Thijn R.

    2015-01-01

    ABSTRACT Rift Valley fever virus (RVFV) causes recurrent insect-borne epizootics throughout the African continent, and infection of humans can lead to a lethal hemorrhagic fever syndrome. Deep mutagenesis of haploid human cells was used to identify host factors required for RVFV infection. This screen identified a suite of enzymes involved in glycosaminoglycan (GAG) biogenesis and transport, including several components of the cis-oligomeric Golgi (COG) complex, one of the central components of Golgi complex trafficking. In addition, disruption of PTAR1 led to RVFV resistance as well as reduced heparan sulfate surface levels, consistent with recent observations that PTAR1-deficient cells exhibit altered Golgi complex morphology and glycosylation defects. A variety of biochemical and genetic approaches were utilized to show that both pathogenic and attenuated RVFV strains require GAGs for efficient infection on some, but not all, cell types, with the block to infection being at the level of virion attachment. Examination of other members of the Bunyaviridae family for GAG-dependent infection suggested that the interaction with GAGs is not universal among bunyaviruses, indicating that these viruses, as well as RVFV on certain cell types, employ additional unidentified virion attachment factors and/or receptors. IMPORTANCE Rift Valley fever virus (RVFV) is an emerging pathogen that can cause severe disease in humans and animals. Epizootics among livestock populations lead to high mortality rates and can be economically devastating. Human epidemics of Rift Valley fever, often initiated by contact with infected animals, are characterized by a febrile disease that sometimes leads to encephalitis or hemorrhagic fever. The global burden of the pathogen is increasing because it has recently disseminated beyond Africa, which is of particular concern because the virus can be transmitted by widely distributed mosquito species. There are no FDA-licensed vaccines or antiviral

  4. Bridging dry spells for maize cropping through supplemental irrigation in the Central Rift Valley of Ethiopia

    NASA Astrophysics Data System (ADS)

    Muluneh Bitew, Alemayehu; Keesstra, Saskia; Stroosnijder, Leo

    2015-04-01

    Maize yield in the Central Rift Valley of Ethiopia (CRV) suffers from dry spells at sensitive growth stages. Risk of crop failure makes farmers reluctant to invest in fertilizer. This makes the CRV food insecure. There are farms with well-maintained terraces and Rain Water Harvesting (RWH) systems using concrete farms ponds. We tested the hypothesis that in these farms supplemental irrigation with simultaneous crop intensification might boost production of a small maize area sufficient to improve food security. Intensification includes a higher plant density of a hybrid variety under optimum fertilization. First we assessed the probability of occurrence of dry spells. Then we estimated the availability of sufficient runoff in the ponds in dry years. During 2012 (dry) and 2013 (wet) on-farm field research was conducted with 10 combinations of supplemental irrigation and plant density. The simplest was rainfed farming with 30,000 plants ha-1. The most advanced was no water stress and 75,000 plants ha-1. Finally we compared our on-farm yield with that of neighbouring farmers. Because 2013 was a wet year no irrigation was needed. Our long term daily rainfall (1970-2011) analysis proves the occurrence of dry spells during the onset of the maize (Belg months March and April). In March there is hardly enough water in the ponds. So, we advise later sowing. Starting from April available water (runoff from a 2.2 ha catchment) matches crop water requirement (for 0.5 ha maize). Significant differences between grain and total biomass yield were observed between rainfed and other irrigation levels. However, since the largest difference is only 12%, the investment in irrigation non-critical drought years is not worth the effort. There was also a limited effect (18-22%) of increasing plant density. So, we advise not to use more than 45,000 plants ha-1. The grain yield and total biomass difference between farmers own practice and our on-farm research was 101% and 84% respectively

  5. Immunogenicity of a Recombinant Rift Valley Fever MP-12-NSm Deletion Vaccine Candidate in Calves

    PubMed Central

    Morrill, John C.; Laughlin, Richard C.; Lokugamage, Nandadeva; Wu, Jing; Pugh, Roberta; Kanani, Pooja; Adams, L. Garry; Makino, Shinji; Peters, C. J.

    2013-01-01

    The safety and immunogenicity of an authentic recombinant (ar) of the live, attenuated MP-12 Rift Valley fever (RVF) vaccine virus with a large deletion of the NSm gene in the pre-Gn region of the M RNA segment (arMP-12ΔNSm21/384) was tested in 4 – 6 month old Bos taurus calves. Phase I of this study evaluated the neutralizing antibody response, measured by 80% plaque reduction neutralization (PRNT80), and clinical response of calves to doses of 1×101 through 1×107 plaque forming units (PFU) administered subcutaneously (s.c.). Phase II evaluated the clinical and neutralizing antibody response of calves inoculated s.c. or intramuscularly (i.m.) with 1×103, 1×104 or 1×105 PFU of arMP-12ΔNSm21/384. No significant adverse clinical events were observed in the animals in these studies. Of all specimens tested, only one vaccine viral isolate was recovered and that virus retained the introduced deletion. In the Phase I study, there was no statistically significant difference in the PRNT80 response between the dosage groups though the difference in IgG response between the 1×101 PFU group and the 1×105 PFU group was statistically significant (p <0.05). The PRNT80 response of the respective dosage groups corresponded to dose of vaccine with the 1×101 PFU dose group showing the least response. The Phase II study also showed no statistically significant difference in PRNT80 response between the dosage groups though the difference in RVFV-specific IgG values was significantly increased (P<0.001) in animals inoculated i.m. with 1×104 or 1×105 PFU versus those inoculated s. c. with 1×103 or 1×105 PFU. Although the study groups were small, these data suggest that 1×104 or 1×105 PFU of arMP-12ΔNSm21/384 administered i.m. to calves will consistently stimulate a presumably protective PRNT80 response for at least 91 days post inoculation. Further studies of arMP-12ΔNSm21/384 are warranted to explore its suitability as an efficacious livestock vaccine. PMID:23994375

  6. A Review of Mosquitoes Associated with Rift Valley Fever Virus in Madagascar

    PubMed Central

    Tantely, Luciano M.; Boyer, Sébastien; Fontenille, Didier

    2015-01-01

    Rift Valley fever (RVF) is a viral zoonotic disease occurring throughout Africa, the Arabian Peninsula, and Madagascar. The disease is caused by a Phlebovirus (RVF virus [RVFV]) transmitted to vertebrate hosts through the bite of infected mosquitoes. In Madagascar, the first RVFV circulation was reported in 1979 based on detection in mosquitoes but without epidemic episode. Subsequently, two outbreaks occurred: the first along the east coast and in the central highlands in 1990 and 1991 and the most recent along the northern and eastern coasts and in the central highlands in 2008 and 2009. Despite the presence of 24 mosquitoes species potentially associated with RVFV transmission in Madagascar, little associated entomological information is available. In this review, we list the RVFV vector, Culex antennatus, as well as other taxa as candidate vector species. We discuss risk factors from an entomological perspective for the re-emergence of RVF in Madagascar. PMID:25732680

  7. Isotopic Evidence for Neogene Hominid Paleoenvironments in the Kenya Rift Valley

    NASA Astrophysics Data System (ADS)

    Kingston, John D.; Marino, Bruno D.; Hill, Andrew

    1994-05-01

    Bipedality, the definitive characteristic of the earliest hominids, has been regarded as an adaptive response to a transition from forested to more-open habitats in East Africa sometime between 12 million and 5 million years ago. Analyses of the stable carbon isotopic composition (δ13C) of paleosol carbonate and organic matter from the Tugen Hills succession in Kenya indicate that a heterogeneous environment with a mix of C3 and C4 plants has persisted for the last 15.5 million years. Open grasslands at no time dominated this portion of the rift valley. The observed δ13C values offer no evidence for a shift from more-closed C3 environments to C4 grassland habitats. If hominids evolved in East Africa during the Late Miocene, they did so in an ecologically diverse setting.

  8. Single-particle cryo-electron microscopy of Rift Valley fever virus

    SciTech Connect

    Sherman, Michael B.; Freiberg, Alexander N.; Holbrook, Michael R.; Watowich, Stanley J.

    2009-04-25

    Rift Valley fever virus (RVFV; Bunyaviridae; Phlebovirus) is an emerging human and veterinary pathogen causing acute hepatitis in ruminants and has the potential to cause hemorrhagic fever in humans. We report a three-dimensional reconstruction of RVFV vaccine strain MP-12 (RVFV MP-12) by cryo-electron microcopy using icosahedral symmetry of individual virions. Although the genomic core of RVFV MP-12 is apparently poorly ordered, the glycoproteins on the virus surface are highly symmetric and arranged on a T = 12 icosahedral lattice. Our RVFV MP-12 structure allowed clear identification of inter-capsomer contacts and definition of possible glycoprotein arrangements within capsomers. This structure provides a detailed model for phleboviruses, opens new avenues for high-resolution structural studies of the bunyavirus family, and aids the design of antiviral diagnostics and effective subunit vaccines.

  9. Isotopic evidence for neogene hominid paleoenvironments in the Kenya Rift Valley

    SciTech Connect

    Kingston, J.D.; Hill, A. ); Marino, B.D. )

    1994-05-13

    Bipedality, the definitive characteristic of the earliest hominids, has been regarded as an adaptive response to a transition from forested to more-open habitats in East Africa sometime between 12 million and 5 million years ago. Analyses of the stable carbon isotopic composition ([delta][sup 13]C) of paleosol carbonate and organic matter from the Tugen Hills succession in Kenya indicate that a heterogeneous environment with a mix of C3 and C4 plants has persisted for the last 15.5 million years. Open grasslands at no time dominated this portion of the rift valley. The observed [delta][sup 13]C values offer no evidence for a shift from more-closed C3 environments to C4 grasslands habitats. If hominids evolved in East Africa during the Late Miocene, they did so in an ecologically diverse setting.

  10. Application of Droplet Digital PCR to Validate Rift Valley Fever Vaccines.

    PubMed

    Ly, Hoai J; Lokugamage, Nandadeva; Ikegami, Tetsuro

    2016-01-01

    Droplet Digital™ polymerase chain reaction (ddPCR™) is a promising technique that quantitates the absolute concentration of nucleic acids in a given sample. This technique utilizes water-in-oil emulsion technology, a system developed by Bio-Rad Laboratories that partitions a single sample into thousands of nanoliter-sized droplets and counts nucleic acid molecules encapsulated in each individual particle as one PCR reaction. This chapter discusses the applications and methodologies of ddPCR for development of Rift Valley fever (RVF) vaccine, using an example that measures RNA copy numbers of a live-attenuated MP-12 vaccine from virus stocks, infected cells, or animal blood. We also discuss how ddPCR detects a reversion mutant of MP-12 from virus stocks accurately. The use of ddPCR improves the quality control of live-attenuated vaccines in the seed lot systems. PMID:27076132

  11. Modelling Rift Valley fever (RVF) disease vector habitats using active and passive remote sensing systems

    NASA Technical Reports Server (NTRS)

    Ambrosia, Vincent G.; Linthicum, K. G.; Bailey, C. L.; Sebesta, P.

    1989-01-01

    The NASA Ames Ecosystem Science and Technology Branch and the U.S. Army Medical Research Institute of Infectious Diseases are conducting research to detect Rift Valley fever (RVF) vector habitats in eastern Africa using active and passive remote-sensing. The normalized difference vegetation index (NDVI) calculated from Landsat TM and SPOT data is used to characterize the vegetation common to the Aedes mosquito. Relationships have been found between the highest NDVI and the 'dambo' habitat areas near Riuru, Kenya on both wet and dry data. High NDVI values, when combined with the vegetation classifications, are clearly related to the areas of vector habitats. SAR data have been proposed for use during the rainy season when optical systems are of minimal use and the short frequency and duration of the optimum RVF mosquito habitat conditions necessitate rapid evaluation of the vegetation/moisture conditions; only then can disease potential be stemmed and eradication efforts initiated.

  12. Repurposing FDA-approved drugs as therapeutics to treat Rift Valley fever virus infection

    PubMed Central

    Benedict, Ashwini; Bansal, Neha; Senina, Svetlana; Hooper, Idris; Lundberg, Lindsay; de la Fuente, Cynthia; Narayanan, Aarthi; Gutting, Bradford; Kehn-Hall, Kylene

    2015-01-01

    There are currently no FDA-approved therapeutics available to treat Rift Valley fever virus (RVFV) infection. In an effort to repurpose drugs for RVFV treatment, a library of FDA-approved drugs was screened to determine their ability to inhibit RVFV. Several drugs from varying compound classes, including inhibitors of growth factor receptors, microtubule assembly/disassembly, and DNA synthesis, were found to reduce RVFV replication. The hepatocellular and renal cell carcinoma drug, sorafenib, was the most effective inhibitor, being non-toxic and demonstrating inhibition of RVFV in a cell-type and virus strain independent manner. Mechanism of action studies indicated that sorafenib targets at least two stages in the virus infectious cycle, RNA synthesis and viral egress. Computational modeling studies also support this conclusion. siRNA knockdown of Raf proteins indicated that non-classical targets of sorafenib are likely important for the replication of RVFV. PMID:26217313

  13. Ultrastructural study of Rift Valley fever virus in the mouse model

    SciTech Connect

    Reed, Christopher; Steele, Keith E.; Honko, Anna; Shamblin, Joshua; Hensley, Lisa E.; Smith, Darci R.

    2012-09-15

    Detailed ultrastructural studies of Rift Valley fever virus (RVFV) in the mouse model are needed to develop and characterize a small animal model of RVF for the evaluation of potential vaccines and therapeutics. In this study, the ultrastructural features of RVFV infection in the mouse model were analyzed. The main changes in the liver included the presence of viral particles in hepatocytes and hepatic stem cells accompanied by hepatocyte apoptosis. However, viral particles were observed rarely in the liver; in contrast, particles were extremely abundant in the CNS. Despite extensive lymphocytolysis, direct evidence of viral replication was not observed in the lymphoid tissue. These results correlate with the acute-onset hepatitis and delayed-onset encephalitis that are dominant features of severe human RVF, but suggest that host immune-mediated mechanisms contribute significantly to pathology. The results of this study expand our knowledge of RVFV-host interactions and further characterize the mouse model of RVF.

  14. Reassortment and distinct evolutionary dynamics of Rift Valley Fever virus genomic segments

    PubMed Central

    Freire, Caio C. M.; Iamarino, Atila; Soumaré, Peinda O. Ly; Faye, Ousmane; Sall, Amadou A.; Zanotto, Paolo M. A.

    2015-01-01

    Rift Valley Fever virus (RVFV) is a member of Bunyaviridae family that causes a febrile disease affecting mainly ruminants and occasionally humans in Africa, with symptoms that range from mid to severe. RVFV has a tri-segmented ssRNA genome that permits reassortment and could generate more virulent strains. In this study, we reveal the importance of reassortment for RVFV evolution using viral gene genealogy inference and phylodynamics. We uncovered seven events of reassortment that originated RVFV lineages with discordant origins among segments. Moreover, we also found that despite similar selection regimens, the three segments have distinct evolutionary dynamics; the longer segment L evolves at a significant lower rate. Episodes of discordance between population size estimates per segment also coincided with reassortment dating. Our results show that RVFV segments are decoupled enough to have distinct demographic histories and to evolve under different molecular rates. PMID:26100494

  15. Reassortment and distinct evolutionary dynamics of Rift Valley Fever virus genomic segments.

    PubMed

    Freire, Caio C M; Iamarino, Atila; Soumaré, Peinda O Ly; Faye, Ousmane; Sall, Amadou A; Zanotto, Paolo M A

    2015-01-01

    Rift Valley Fever virus (RVFV) is a member of Bunyaviridae family that causes a febrile disease affecting mainly ruminants and occasionally humans in Africa, with symptoms that range from mid to severe. RVFV has a tri-segmented ssRNA genome that permits reassortment and could generate more virulent strains. In this study, we reveal the importance of reassortment for RVFV evolution using viral gene genealogy inference and phylodynamics. We uncovered seven events of reassortment that originated RVFV lineages with discordant origins among segments. Moreover, we also found that despite similar selection regimens, the three segments have distinct evolutionary dynamics; the longer segment L evolves at a significant lower rate. Episodes of discordance between population size estimates per segment also coincided with reassortment dating. Our results show that RVFV segments are decoupled enough to have distinct demographic histories and to evolve under different molecular rates. PMID:26100494

  16. Distribution of Upper Pliocene brines in the northern Jordan Rift Valley, Israel and Jordan

    NASA Astrophysics Data System (ADS)

    Siebert, Christian; Möller, Peter; Rosenthal, Eliyahu; Guttman, Joseph; Yellin-Dror, Annat; Inbar, Nimrod; Magri, Fabien

    2014-05-01

    In the triangle of Lake Tiberias (LT), Yarmouk Gorge and Lower Jordan Valley (Fig. 1), fresh groundwaters are frequently deteriorated by variable admixture of ascending subsurface Upper-Pliocene brines. Element ratios and water isotopes reveal, that common source brine is present and is modified by water rock interaction and dilution with freshwater. This common source brine is inferred from the composition of the known Ha'on well brine being characterized by molar ratios of Na/Cl=0.53, 1000Br/Cl=5.5 and Ca/Mg=0.39 (Möller et al., 2011). The low Ca/Mg, a ratio also found for Newe Ur, is unique in an environment in which ratios >1 dominate because of omnipresent dolomitization of abundant limestones. Interaction with abundant intrusive basaltic bodies would add sodium and hence increase the low Na/Cl ratio to >1. Uptake of halite increases Na/Cl but decreases Br/Cl ratios. These ratios resemble seawater after 37-fold enrichment in Li molality by evaporation (McCaffrey et al. 1987). Although being diluted by freshwater the Ha'on well brine proves the presence of an evaporated seawater mother brine residing at unknown depth. The derivatives of inferred Ha'on mother brine are present around Lake Tiberias, in the lower Yarmouk Valley and in the northern Rift Valley at least as far southwards as Newe Ur. Areas of structural weakness, where the major fault systems occur, are the main distribution areas for these brines. The study provides an example whereby hydrochemical analyses are applied as key tool to better understand deep fluid transport processes at basin-scale, which are supported by numerical modeling of groundwater flow. Möller P., Siebert C., Geyer S., Inbar N., Rosenthal E., Flexer A., Zilberbrand M. (2011): Relationship of brines in the Kinnarot Basin, Jordan-Dead Sea Rift Valley. Geofluids 12(2): 166-181. McCaffrey M.A., Lazar B., Holland H.D. (1987): The evaporation path of seawater and the coprecipitation of Br- and K+ with halite. J. Sediment. Petrol

  17. Experimental Infection of Calves by Two Genetically-Distinct Strains of Rift Valley Fever Virus.

    PubMed

    Wilson, William C; Davis, A Sally; Gaudreault, Natasha N; Faburay, Bonto; Trujillo, Jessie D; Shivanna, Vinay; Sunwoo, Sun Young; Balogh, Aaron; Endalew, Abaineh; Ma, Wenjun; Drolet, Barbara S; Ruder, Mark G; Morozov, Igor; McVey, D Scott; Richt, Juergen A

    2016-01-01

    Recent outbreaks of Rift Valley fever in ruminant livestock, characterized by mass abortion and high mortality rates in neonates, have raised international interest in improving vaccine control strategies. Previously, we developed a reliable challenge model for sheep that improves the evaluation of existing and novel vaccines in sheep. This sheep model demonstrated differences in the pathogenesis of Rift Valley fever virus (RVFV) infection between two genetically-distinct wild-type strains of the virus, Saudi Arabia 2001 (SA01) and Kenya 2006 (Ken06). Here, we evaluated the pathogenicity of these two RVFV strains in mixed breed beef calves. There was a transient increase in rectal temperatures with both virus strains, but this clinical sign was less consistent than previously reported with sheep. Three of the five Ken06-infected animals had an early-onset viremia, one day post-infection (dpi), with viremia lasting at least three days. The same number of SA01-infected animals developed viremia at 2 dpi, but it only persisted through 3 dpi in one animal. The average virus titer for the SA01-infected calves was 1.6 logs less than for the Ken06-infected calves. Calves, inoculated with either strain, seroconverted by 5 dpi and showed time-dependent increases in their virus-neutralizing antibody titers. Consistent with the results obtained in the previous sheep study, elevated liver enzyme levels, more severe liver pathology and higher virus titers occurred with the Ken06 strain as compared to the SA01 strain. These results demonstrate the establishment of a virulent challenge model for vaccine evaluation in calves. PMID:27223298

  18. Broad Spectrum Antiviral Activity of Favipiravir (T-705): Protection from Highly Lethal Inhalational Rift Valley Fever

    PubMed Central

    Caroline, Amy L.; Powell, Diana S.; Bethel, Laura M.; Oury, Tim D.; Reed, Douglas S.; Hartman, Amy L.

    2014-01-01

    Background Development of antiviral drugs that have broad-spectrum activity against a number of viral infections would be of significant benefit. Due to the evolution of resistance to currently licensed antiviral drugs, development of novel anti-influenza drugs is in progress, including Favipiravir (T-705), which is currently in human clinical trials. T-705 displays broad-spectrum in vitro activity against a number of viruses, including Rift Valley Fever virus (RVFV). RVF is an important neglected tropical disease that causes human, agricultural, and economic losses in endemic regions. RVF has the capacity to emerge in new locations and also presents a potential bioterrorism threat. In the current study, the in vivo efficacy of T-705 was evaluated in Wistar-Furth rats infected with the virulent ZH501 strain of RVFV by the aerosol route. Methodology/Principal Findings Wistar-Furth rats are highly susceptible to a rapidly lethal disease after parenteral or inhalational exposure to the pathogenic ZH501 strain of RVFV. In the current study, two experiments were performed: a dose-determination study and a delayed-treatment study. In both experiments, all untreated control rats succumbed to disease. Out of 72 total rats infected with RVFV and treated with T-705, only 6 succumbed to disease. The remaining 66 rats (92%) survived lethal infection with no significant weight loss or fever. The 6 treated rats that succumbed survived significantly longer before succumbing to encephalitic disease. Conclusions/Significance Currently, there are no licensed antiviral drugs for treating RVF. Here, T-705 showed remarkable efficacy in a highly lethal rat model of Rift Valley Fever, even when given up to 48 hours post-infection. This is the first study to show protection of rats infected with the pathogenic ZH501 strain of RVFV. Our data suggest that T-705 has potential to be a broad-spectrum antiviral drug. PMID:24722586

  19. Rift Valley Fever Risk Map Model and Seroprevalence in Selected Wild Ungulates and Camels from Kenya

    NASA Technical Reports Server (NTRS)

    Britch, Seth C.; Binepal, Yatinder S.; Ruder, Mark G.; Kariithi, Henry M.; Linthicum, Kenneth J.; Anyamba, Assaf; Small, Jennifer L.; Tucker, Compton J.; Ateya, Leonard O.; Oriko, Abuu A.; Gacheru, Stephen; Wilson, William C.

    2013-01-01

    Since the first isolation of Rift Valley fever virus (RVFV) in the 1930s, there have been multiple epizootics and epidemics in animals and humans in sub-Saharan Africa. Prospective climate-based models have recently been developed that flag areas at risk of RVFV transmission in endemic regions based on key environmental indicators that precede Rift Valley fever (RVF) epizootics and epidemics. Although the timing and locations of human case data from the 2006-2007 RVF outbreak in Kenya have been compared to risk zones flagged by the model, seroprevalence of RVF antibodies in wildlife has not yet been analyzed in light of temporal and spatial predictions of RVF activity. Primarily wild ungulate serum samples from periods before, during, and after the 2006-2007 RVF epizootic were analyzed for the presence of RVFV IgM and/or IgG antibody. Results show an increase in RVF seropositivity from samples collected in 2007 (31.8%), compared to antibody prevalence observed from 2000-2006 (3.3%). After the epizootic, average RVF seropositivity diminished to 5% in samples collected from 2008-2009. Overlaying maps of modeled RVF risk assessments with sampling locations indicated positive RVF serology in several species of wild ungulate in or near areas flagged as being at risk for RVF. Our results establish the need to continue and expand sero-surveillance of wildlife species Kenya and elsewhere in the Horn of Africa to further calibrate and improve the RVF risk model, and better understand the dynamics of RVFV transmission.

  20. Experimental Infection of Calves by Two Genetically-Distinct Strains of Rift Valley Fever Virus

    PubMed Central

    Wilson, William C.; Davis, A. Sally; Gaudreault, Natasha N.; Faburay, Bonto; Trujillo, Jessie D.; Shivanna, Vinay; Sunwoo, Sun Young; Balogh, Aaron; Endalew, Abaineh; Ma, Wenjun; Drolet, Barbara S.; Ruder, Mark G.; Morozov, Igor; McVey, D. Scott; Richt, Juergen A.

    2016-01-01

    Recent outbreaks of Rift Valley fever in ruminant livestock, characterized by mass abortion and high mortality rates in neonates, have raised international interest in improving vaccine control strategies. Previously, we developed a reliable challenge model for sheep that improves the evaluation of existing and novel vaccines in sheep. This sheep model demonstrated differences in the pathogenesis of Rift Valley fever virus (RVFV) infection between two genetically-distinct wild-type strains of the virus, Saudi Arabia 2001 (SA01) and Kenya 2006 (Ken06). Here, we evaluated the pathogenicity of these two RVFV strains in mixed breed beef calves. There was a transient increase in rectal temperatures with both virus strains, but this clinical sign was less consistent than previously reported with sheep. Three of the five Ken06-infected animals had an early-onset viremia, one day post-infection (dpi), with viremia lasting at least three days. The same number of SA01-infected animals developed viremia at 2 dpi, but it only persisted through 3 dpi in one animal. The average virus titer for the SA01-infected calves was 1.6 logs less than for the Ken06-infected calves. Calves, inoculated with either strain, seroconverted by 5 dpi and showed time-dependent increases in their virus-neutralizing antibody titers. Consistent with the results obtained in the previous sheep study, elevated liver enzyme levels, more severe liver pathology and higher virus titers occurred with the Ken06 strain as compared to the SA01 strain. These results demonstrate the establishment of a virulent challenge model for vaccine evaluation in calves. PMID:27223298

  1. Searching for evidence of changes in extreme rainfall indices in the Central Rift Valley of Ethiopia

    NASA Astrophysics Data System (ADS)

    Muluneh, Alemayehu; Bewket, Woldeamlak; Keesstra, Saskia; Stroosnijder, Leo

    2016-02-01

    Extreme rainfall events have serious implications for economic sectors with a close link to climate such as agriculture and food security. This holds true in the Central Rift Valley (CRV) of Ethiopia where communities rely on highly climate-sensitive rainfed subsistence farming for livelihoods. This study investigates changes in ten extreme rainfall indices over a period of 40 years (1970-2009) using 14 meteorological stations located in the CRV. The CRV consists of three landscape units: the valley floor, the escarpments, and the highlands all of which are considered in our data analysis. The Belg (March-May) and Kiremt (June-September) seasons are also considered in the analysis. The Mann-Kendall test was used to detect trends of the rainfall indices. The results indicated that at the annual time scale, more than half (57 %) of the stations showed significant trends in total wet-day precipitation (PRCPTOT) and heavy precipitation days (R10mm). Only 7-35 % of stations showed significant trends, for the other rainfall indices. Spatially, the valley floor received increasing annual rainfall while the escarpments and the highlands received decreasing annual rainfall over the last 40 years. During Belg, 50 % of the stations showed significant increases in the maximum number of consecutive dry days (CDD) in all parts of the CRV. However, most other rainfall indices during Belg showed no significant changes. During Kiremt, considering both significant and non-significant trends, almost all rainfall indices showed an increasing trend in the valley floor and a decreasing trend in the escarpment and highlands. During Belg and Kiremt, the CDD generally showed increasing tendency in the CRV.

  2. Scaling relations for large Martian valleys

    NASA Astrophysics Data System (ADS)

    Som, Sanjoy M.; Montgomery, David R.; Greenberg, Harvey M.

    2009-02-01

    The dendritic morphology of Martian valley networks, particularly in the Noachian highlands, has long been argued to imply a warmer, wetter early Martian climate, but the character and extent of this period remains controversial. We analyzed scaling relations for the 10 large valley systems incised in terrain of various ages, resolvable using the Mars Orbiter Laser Altimeter (MOLA) and the Thermal Emission Imaging System (THEMIS). Four of the valleys originate in point sources with negligible contributions from tributaries, three are very poorly dissected with a few large tributaries separated by long uninterrupted trunks, and three exhibit the dendritic, branching morphology typical of terrestrial channel networks. We generated width-area and slope-area relationships for each because these relations are identified as either theoretically predicted or robust terrestrial empiricisms for graded precipitation-fed, perennial channels. We also generated distance-area relationships (Hack's law) because they similarly represent robust characteristics of terrestrial channels (whether perennial or ephemeral). We find that the studied Martian valleys, even the dendritic ones, do not satisfy those empiricisms. On Mars, the width-area scaling exponent b of -0.7-4.7 contrasts with values of 0.3-0.6 typical of terrestrial channels; the slope-area scaling exponent $\\theta$ ranges from -25.6-5.5, whereas values of 0.3-0.5 are typical on Earth; the length-area, or Hack's exponent n ranges from 0.47 to 19.2, while values of 0.5-0.6 are found on Earth. None of the valleys analyzed satisfy all three relations typical of terrestrial perennial channels. As such, our analysis supports the hypotheses that ephemeral and/or immature channel morphologies provide the closest terrestrial analogs to the dendritic networks on Mars, and point source discharges provide terrestrial analogs best suited to describe the other large Martian valleys.

  3. The Rift Valley of African Plate in Elasto-Plastic Creeping over Magma Motion

    NASA Astrophysics Data System (ADS)

    Nakamura, Shigehisa

    2016-04-01

    This is a brief note to a problem on the Rift Valley in the eastern Africa. It is said that this valley was formed in an age 20,000,000 years before present though the valley is yet continuing to move eastward at an annual rate of about 5 cm/year in a geographical trend. Adding to some of the scientists tell that the separation threat of the easternAfrica from the mother land of the Africa under the effect of African crust motion over the magma. However, it is now geological understanding that the land of the Africa has been kept its basic coastal configulation in geographic pattern since the time more than 20,000,000 years before present. Sothat, it is hard to consider the above noted African land separation by part could be in the next age in a time scale of 20,000,000 years. As far as, we concern the geographic data obtaoned by the ground based survey of the African typical mountain peaks, the highest mountain peak 5885m (in 1980) is for Kilimanjaro, Kibo Peak though one of the scientific almanacs tells us its peak height as 5890m (in 2009). As for the Mount Kenia, the peak height is as 5199m (in 1980) and 5200m(in 2009). At a glance, it looks to be a trend in altimetry of the African typical mountain. Now, what trends are noted for the peak heights could be taken to suggesting the geological activity on the earth surface to maintain in a spherical shape approximately on the orbit around the Sun. In these several ten years, the digitizing of the data has been promoted even for the topographic patterns on the earth though its time scaling is extremely short comparing to the geological time scaling. Now, it should be found what is effective to monitor any trends of the African crust in motion as well as variations of the mountain peaks.

  4. Development of a diagnostic one-tube RT-PCR for the detection of Rift Valley fever virus.

    PubMed

    Espach, A; Romito, M; Nel, L H; Viljoen, G J

    2002-09-01

    Diagnosis of Rift Valley fever (RVF) is based on serology and virus isolation. The disadvantages of the former include poor sensitivity, high cost, risks associated with using infectious virus as antigen, the lengthy duration of ELISA as well as cross-reactivity with other Phleboviruses. We developed, optimised and evaluated a one-tube reverse-transcription-polymerase chain reaction (RT-PCR) for the detection of Rift Valley fever virus (RVFV) in ruminants. The PCR primers for this assay were designed to anneal to a region within the M segment of the virus genome, encoding glycoproteins G1 and G2. A PCR amplicon of 363 bp was obtained. The sensitivity of the assay was determined to be 0.25 TCID50. This test should allow for the early and rapid detection of RVFV in both serum and whole blood. In addition, it could facilitate the quantification of antigen for the manufacture of current vaccines. PMID:12356173

  5. [Epidemiology of Rift Valley fever in western Africa. I. Serologic survey in domestic ruminants of Burkina Faso].

    PubMed

    Akakpo, A J; Some, M J; Bornarel, P; Jouan, A; Gonzalez, J P

    1989-01-01

    A serosurvey of Rift valley fever virus infection has been conducted among 2,410 domestic ruminants (sheep, goats and cattle) from Burkina Faso in 1985, 1986 and 1987. An active circulation of virus was demonstrated and 26.7% of the total animal tested had Rift valley fever virus reacting antibodies. An epizootic was demonstrated retrospectively for 1987 and appears to correspond to the RVF outbreak observed in the same type of sahelian environment during the same year in Mauritania. Analogous ecoclimatic and environmental risk factors are discussed. Others phleboviruses such as Arumowot, Gordil, Saint-Floris, Gabek Forest and Odrenisrou seem to be active in some areas but no evidence of pathogenesis for domestic ruminants was demonstrated. PMID:2766443

  6. An observational study of the summer Mediterranean Sea breeze front penetration into the complex topography of the Jordan Rift Valley

    NASA Astrophysics Data System (ADS)

    Naor, R.; Potchter, O.; Shafir, H.; Alpert, P.

    2015-09-01

    The Mediterranean summer sea breeze front (SBF) climatic features of penetration into the complex topography of the Jordan Rift Valley (JRV) were investigated. It was shown that the SBF penetration into the JRV occurs in a well-defined chronological order from north to south. One exception to this general rule is the breeze penetration of Sdom, which occurs after it has penetrated the Arava which is located further south, probably due to the micro-climatic effect of the Dead Sea. It was also noted that the breeze increases the local specific humidity as it reaches the JRV in spite of significant temperature increases. The temperature reaches its daily peak 2 to 3 h later in the southern valley compared to the northern valley and is suggested to be due to the later SBF penetration and the valley structure. The pre-SBF line features in the JRV are described.

  7. Roles of the Coding and Noncoding Regions of Rift Valley Fever Virus RNA Genome Segments in Viral RNA Packaging

    PubMed Central

    Murakami, Shin; Terasaki, Kaori; Narayanan, Krishna

    2012-01-01

    We characterized the RNA elements involved in the packaging of Rift Valley fever virus RNA genome segments, L, M, and S. The 5′-terminal 25 nucleotides of each RNA segment were equally competent for RNA packaging and carried an RNA packaging signal, which overlapped with the RNA replication signal. Only the deletion mutants of L RNA, but not full-length L RNA, were efficiently packaged, implying the possible requirement of RNA compaction for L RNA packaging. PMID:22278239

  8. Seroprevalence of Rift Valley fever virus in sheep and goats in Zambézia, Mozambique

    PubMed Central

    Blomström, Anne-Lie; Scharin, Isabelle; Stenberg, Hedvig; Figueiredo, Jaquline; Nhambirre, Ofélia; Abilio, Ana; Berg, Mikael; Fafetine, José

    2016-01-01

    Background The Rift Valley fever virus (RVFV) is a vector-borne virus that causes disease in ruminants, but it can also infect humans. In humans, the infection can be asymptomatic but can also lead to illness, ranging from a mild disease with fever, headache and muscle pain to a severe disease with encephalitis and haemorrhagic fever. In rare cases, death can occur. In infected animals, influenza-like symptoms can occur, and abortion and mortality in young animals are indicative of RVFV infection. Since the initial outbreak in Kenya in the 1930s, the virus has become endemic to most of sub-Saharan Africa. In 2000, the virus appeared in Yemen and Saudi Arabia; this was the first outbreak of RVF outside of Africa. Rift Valley fever epidemics are often connected to heavy rainfall, leading to an increased vector population and spread of the virus to animals and/or humans. However, the virus needs to be maintained during the inter-epidemic periods. In this study, we investigated the circulation of RVFV in small ruminants (goats and sheep) in Zambézia, Mozambique, an area with a close vector/wildlife/livestock/human interface. Materials and methods Between September and October 2013, 181 sheep and 187 goat blood samples were collected from eight localities in the central region of Zambézia, Mozambique. The samples were analysed for the presence of antibodies against RVFV using a commercial competitive ELISA. Results and discussion The overall seroprevalence was higher in sheep (44.2%) than goats (25.1%); however, there was a high variation in seroprevalence between different localities. The data indicate an increased seroprevalence for sheep compared to 2010, when a similar study was conducted in this region and in overlapping villages. No noticeable health problems in the herds were reported. Conclusions This study shows an inter-epidemic circulation of RVFV in small ruminants in Zambézia, Mozambique. Neither outbreaks of RVF nor typical clinical signs of RVFV have

  9. Postepidemic Analysis of Rift Valley Fever Virus Transmission in Northeastern Kenya: A Village Cohort Study

    PubMed Central

    LaBeaud, A. Desirée; Muiruri, Samuel; Sutherland, Laura J.; Dahir, Saidi; Gildengorin, Ginny; Morrill, John; Muchiri, Eric M.; Peters, Clarence J.; King, Charles H.

    2011-01-01

    Background In endemic areas, Rift Valley fever virus (RVFV) is a significant threat to both human and animal health. Goals of this study were to measure human anti-RVFV seroprevalence in a high-risk area following the 2006–2007 Kenyan Rift Valley Fever (RVF) epidemic, to identify risk factors for interval seroconversion, and to monitor individuals previously exposed to RVFV in order to document the persistence of their anti-RVFV antibodies. Methodology/Findings We conducted a village cohort study in Ijara District, Northeastern Province, Kenya. One hundred two individuals tested for RVFV exposure before the 2006–2007 RVF outbreak were restudied to determine interval anti-RVFV seroconversion and persistence of humoral immunity since 2006. Ninety-two additional subjects were enrolled from randomly selected households to help identify risk factors for current seropositivity. Overall, 44/194 or 23% (CI95%:17%–29%) of local residents were RVFV seropositive. 1/85 at-risk individuals restudied in the follow-up cohort had seroconverted since early 2006. 27/92 (29%, CI95%: 20%–39%) of newly tested individuals were seropositive. All 13 individuals with positive titers (by plaque reduction neutralization testing (PRNT80)) in 2006 remained positive in 2009. After adjustment in multivariable logistic models, age, village, and drinking raw milk were significantly associated with RVFV seropositivity. Visual impairment (defined as ≤20/80) was much more likely in the RVFV-seropositive group (P<0.0001). Conclusions Our results highlight significant variability in RVFV exposure in two neighboring villages having very similar climate, terrain, and insect density. Among those with previous exposure, RVFV titers remained at >1∶40 for more than 3 years. In concordance with previous studies, residents of the more rural village were more likely to be seropositive and RVFV seropositivity was associated with poor visual acuity. Raw milk consumption was strongly associated with

  10. The Olorgesailie Drilling Project (ODP): a high-resolution drill core record from a hominin site in the East African Rift Valley

    NASA Astrophysics Data System (ADS)

    Dommain, R.; Potts, R.; Behrensmeyer, A. K.; Deino, A. L.

    2014-12-01

    The East African rift valley contains an outstanding record of hominin fossils that document human evolution over the Plio-Pleistocene when the global and regional climate and the rift valley itself changed markedly. The sediments of fossil localities typically provide, however, only short time windows into past climatic and environmental conditions. Continuous, long-term terrestrial records are now becoming available through core drilling to help elucidate the paleoenvironmental context of human evolution. Here we present a 500,000 year long high-resolution drill core record obtained from a key fossil and archeological site - the Olorgesailie Basin in the southern Kenya Rift Valley, well known for its sequence of archeological and faunal sites for the past 1.2 million years. In 2012 two drill cores (54 and 166 m long) were collected in the Koora Plain just south of Mt. Olorgesailie as part of the Olorgesailie Drilling Project (ODP) to establish a detailed climate and ecological record associated with the last evidence of Homo erectus in Africa, the oldest transition of Acheulean to Middle Stone Age technology, and large mammal species turnover, all of which are documented in the Olorgesailie excavations. The cores were sampled at the National Lacustrine Core Facility. More than 140 samples of tephra and trachytic basement lavas have led to high-precision 40Ar/39Ar dating. The cores are being analyzed for a suite of paleoclimatic and paleoecological proxies such as diatoms, pollen, fungal spores, phytoliths, ostracodes, carbonate isotopes, leaf wax biomarkers, charcoal, and clay mineralogy. Sedimentological analyses, including lithological descriptions, microscopic smear slide analysis (242 samples), and grain-size analysis, reveal a highly variable sedimentary sequence of deep lake phases with laminated sediments, diatomites, shallow lake and near shore phases, fluvial deposits, paleosols, interspersed carbonate layers, and abundant volcanic ash deposits. Magnetic

  11. DoD-GEIS Rift Valley Fever Monitoring and Prediction System as a Tool for Defense and US Diplomacy

    NASA Technical Reports Server (NTRS)

    Anyamba, Assaf; Tucker, Compton J.; Linthicum, Kenneth J.; Witt, Clara J.; Gaydos, Joel C.; Russell, Kevin L.

    2011-01-01

    Over the last 10 years the Armed Forces Health Surveillance Center's Global Emerging Infections Surveillance and Response System (GEIS) partnering with NASA'S Goddard Space Flight Center and USDA's USDA-Center for Medical, Agricultural & Veterinary Entomology established and have operated the Rift Valley fever Monitoring and Prediction System to monitor, predict and assess the risk of Rift Valley fever outbreaks and other vector-borne diseases over Africa and the Middle East. This system is built on legacy DoD basic research conducted by Walter Reed Army Institute of Research overseas laboratory (US Army Medical Research Unit-Kenya) and the operational satellite environmental monitoring by NASA GSFC. Over the last 10 years of operation the system has predicted outbreaks of Rift Valley fever in the Horn of Africa, Sudan, South Africa and Mauritania. The ability to predict an outbreak several months before it occurs provides early warning to protect deployed forces, enhance public health in concerned countries and is a valuable tool use.d by the State Department in US Diplomacy. At the international level the system has been used by the Food and Agricultural Organization (FAD) and the World Health Organization (WHO) to support their monitoring, surveillance and response programs in the livestock sector and human health. This project is a successful testament of leveraging resources of different federal agencies to achieve objectives of force health protection, health and diplomacy.

  12. Presence of Viral RNA and Proteins in Exosomes from Cellular Clones Resistant to Rift Valley Fever Virus Infection.

    PubMed

    Ahsan, Noor A; Sampey, Gavin C; Lepene, Ben; Akpamagbo, Yao; Barclay, Robert A; Iordanskiy, Sergey; Hakami, Ramin M; Kashanchi, Fatah

    2016-01-01

    Rift Valley Fever Virus (RVFV) is a RNA virus that belongs to the genus Phlebovirus, family Bunyaviridae. It infects humans and livestock and causes Rift Valley fever. RVFV is considered an agricultural pathogen by the USDA, as it can cause up to 100% abortion in cattle and extensive death of newborns. In addition, it is designated as Category A pathogen by the CDC and the NIAID. In some human cases of RVFV infection, the virus causes fever, ocular damage, liver damage, hemorrhagic fever, and death. There are currently limited options for vaccine candidates, which include the MP-12 and clone 13 versions of RVFV. Viral infections often deregulate multiple cellular pathways that contribute to replication and host pathology. We have previously shown that latent human immunodeficiency virus-1 (HIV-1) and human T-cell lymphotropic virus-1 (HTLV-1) infected cells secrete exosomes that contain short viral RNAs, limited number of genomic RNAs, and viral proteins. These exosomes largely target neighboring cells and activate the NF-κB pathway, leading to cell proliferation, and overall better viral replication. In this manuscript, we studied the effects of exosome formation from RVFV infected cells and their function on recipient cells. We initially infected cells, isolated resistant clones, and further purified using dilution cloning. We then characterized these cells as resistant to new RVFV infection, but sensitive to other viral infections, including Venezuelan Equine Encephalitis Virus (VEEV). These clones contained normal markers (i.e., CD63) for exosomes and were able to activate the TLR pathway in recipient reporter cells. Interestingly, the exosome rich preparations, much like their host cell, contained viral RNA (L, M, and S genome). The RNAs were detected using qRT-PCR in both parental and exosomal preparations as well as in CD63 immunoprecipitates. Viral proteins such as N and a modified form of NSs were present in some of these exosomes. Finally, treatment of

  13. Presence of Viral RNA and Proteins in Exosomes from Cellular Clones Resistant to Rift Valley Fever Virus Infection

    PubMed Central

    Ahsan, Noor A.; Sampey, Gavin C.; Lepene, Ben; Akpamagbo, Yao; Barclay, Robert A.; Iordanskiy, Sergey; Hakami, Ramin M.; Kashanchi, Fatah

    2016-01-01

    Rift Valley Fever Virus (RVFV) is a RNA virus that belongs to the genus Phlebovirus, family Bunyaviridae. It infects humans and livestock and causes Rift Valley fever. RVFV is considered an agricultural pathogen by the USDA, as it can cause up to 100% abortion in cattle and extensive death of newborns. In addition, it is designated as Category A pathogen by the CDC and the NIAID. In some human cases of RVFV infection, the virus causes fever, ocular damage, liver damage, hemorrhagic fever, and death. There are currently limited options for vaccine candidates, which include the MP-12 and clone 13 versions of RVFV. Viral infections often deregulate multiple cellular pathways that contribute to replication and host pathology. We have previously shown that latent human immunodeficiency virus-1 (HIV-1) and human T-cell lymphotropic virus-1 (HTLV-1) infected cells secrete exosomes that contain short viral RNAs, limited number of genomic RNAs, and viral proteins. These exosomes largely target neighboring cells and activate the NF-κB pathway, leading to cell proliferation, and overall better viral replication. In this manuscript, we studied the effects of exosome formation from RVFV infected cells and their function on recipient cells. We initially infected cells, isolated resistant clones, and further purified using dilution cloning. We then characterized these cells as resistant to new RVFV infection, but sensitive to other viral infections, including Venezuelan Equine Encephalitis Virus (VEEV). These clones contained normal markers (i.e., CD63) for exosomes and were able to activate the TLR pathway in recipient reporter cells. Interestingly, the exosome rich preparations, much like their host cell, contained viral RNA (L, M, and S genome). The RNAs were detected using qRT-PCR in both parental and exosomal preparations as well as in CD63 immunoprecipitates. Viral proteins such as N and a modified form of NSs were present in some of these exosomes. Finally, treatment of

  14. Human Dispersals Along the African Rift Valley in the Late Quaternary

    NASA Astrophysics Data System (ADS)

    Tryon, C. A.; Faith, J. T.; Peppe, D. J.

    2014-12-01

    Climate- and tectonic-driven environmental dynamics of the East African Rift System (EARS) during the Quaternary played an important role in the demographic history of early Homo sapiens, including expansions of modern humans across and out of Africa. Human forager population size, geographic range, and behaviors such as hunting strategies and residential mobility likely varied in response to changes in the local and regional environment. Throughout the Quaternary, floral and faunal change was linked at least in part to variations in moisture availability, temperature, and atmospheric CO2, which in addition to uplift and faulting, contributed to the expansion and contraction of a number of large lakes that served as biogeographic barriers to many taxa. This is particularly clear for the Lake Victoria basin, where biogeographic, geological, and paleontological evidence documents repeated expansion and contraction of the ranges of species in response to lake level and vegetation change. Across much of eastern Africa, the topography of the rift facilitated north-south dispersals, the timing of which may have depended in part on the expansion and contraction of the equatorial forest belt. Dispersal potential likely increased during the more arid periods of the late Quaternary, when the roles of lakes and forests as dispersal barriers was reduced and the extent of low net primary productivity dry grasslands increased, the latter requiring large home ranges for human foragers, conditions suitable for range expansions within H. sapiens.

  15. Structure of the active rift zone and margins of the northern Imperial Valley from Salton Seismic Imaging Project (SSIP) data

    NASA Astrophysics Data System (ADS)

    Livers, A.; Han, L.; Delph, J. R.; White-Gaynor, A. L.; Petit, R.; Hole, J. A.; Stock, J. M.; Fuis, G. S.

    2012-12-01

    First-arrival refraction data were used to create a seismic velocity model of the upper crust across the actively rifting northern Imperial Valley and its margins. The densely sampled seismic refraction data were acquired by the Salton Seismic Imaging Project (SSIP) , which is investigating rift processes in the northern-most rift segment of the Gulf of California extensional province and earthquake hazards at the southern end of the San Andreas Fault system. A 95-km long seismic line was acquired across the northern Imperial Valley, through the Salton Sea geothermal field, parallel to the five Salton Butte volcanoes and perpendicular to the Brawley Seismic Zone and major strike-slip faults. Nineteen explosive shots were recorded with 100 m seismometer spacing across the valley and with 300-500 m spacing into the adjacent ranges. First-arrival travel times were picked from shot gathers along this line and a seismic velocity model was produced using tomographic inversion. Sedimentary basement and seismic basement in the valley are interpreted to be sediment metamorphosed by the very high heat flow. The velocity model shows that this basement to the west of the Brawley Seismic Zone is at ~4-km depth. The basement shallows to ~2-km depth in the active geothermal field and Salton Buttes volcanic field which locally coincide with the Brawley Seismic Zone. At the eastern edge of the geothermal field, the basement drops off again to ~3.5-km depth. The eastern edge of the valley appears to be fault bounded by the along-strike extension of the Sand Hills Fault, an inactive strike-slip fault. The seismic velocities to the east of the fault correspond to metamorphic rock of the Chocolate Mountains, different from the metamorphosed basement in the valley. The western edge of the valley appears to be fault bounded by the active Superstition Hills Fault. To the west of the valley, >4-km deep valley basement extends to the active Superstition Hills Fault. Basement then shallows

  16. Wicking assay for the rapid detection of Rift Valley fever viral antigens in mosquitoes (Diptera: Culicidae).

    PubMed

    Turell, M; Davé, K; Mayda, M; Parker, Z; Coleman, R; Davé, S; Strickman, D

    2011-05-01

    Rift Valley fever virus (RVFV) causes outbreaks of severe disease in domestic ungulates as well as humans in Africa. There is a logical concern that RVFV could be introduced into the Americas and cause significant health and economic damage based on the precedent of the introduction and spread of West Nile virus (WNV). Unfortunately, there are currently no licensed diagnostic assays available for RVFV in the Americas. In this work, we report on the ability of a novel dipstick assay, VectorTest RVFV antigen assay, modeled on the VecTest assay for WNV, to detect a RVFV-infected female within a pool of mosquitoes. The dipsticks provided results in <20 min, were easy to use, and did not require a laboratory with containment facilities. Although readily able to detect a mosquito with a disseminated RVFV infection, it only occasionally detected RVFV in a mosquito with a nondisseminated infection, and therefore may fail to detect some pools that actually contain one or more positive mosquitoes. The RVFV dipstick assay was highly specific and did not react with samples to which had been added yellow fever, West Nile, Venezuelan equine encephalitis, sandfly fever Naples, sandfly fever Sicilian, or sandfly fever Toscana viruses. The RVFV assay can provide a rapid, safe, easy-to-use assay to alert public health personnel to the presence of RVFV in mosquitoes. Results from this assay will allow a rapid threat assessment and the focusing of vector control measures in high-risk areas. PMID:21661324

  17. Mutational Analysis of the Rift Valley Fever Virus Glycoprotein Precursor Proteins for Gn Protein Expression

    PubMed Central

    Phoenix, Inaia; Lokugamage, Nandadeva; Nishiyama, Shoko; Ikegami, Tetsuro

    2016-01-01

    The Rift Valley fever virus (RVFV) M-segment encodes the 78 kD, NSm, Gn, and Gc proteins. The 1st AUG generates the 78 kD-Gc precursor, the 2nd AUG generates the NSm-Gn-Gc precursor, and the 3rd AUG makes the NSm’-Gn-Gc precursor. To understand biological changes due to abolishment of the precursors, we quantitatively measured Gn secretion using a reporter assay, in which a Gaussia luciferase (gLuc) protein is fused to the RVFV M-segment pre-Gn region. Using the reporter assay, the relative expression of Gn/gLuc fusion proteins was analyzed among various AUG mutants. The reporter assay showed efficient secretion of Gn/gLuc protein from the precursor made from the 2nd AUG, while the removal of the untranslated region upstream of the 2nd AUG (AUG2-M) increased the secretion of the Gn/gLuc protein. Subsequently, recombinant MP-12 strains encoding mutations in the pre-Gn region were rescued, and virological phenotypes were characterized. Recombinant MP-12 encoding the AUG2-M mutation replicated slightly less efficiently than the control, indicating that viral replication is further influenced by the biological processes occurring after Gn expression, rather than the Gn abundance. This study showed that, not only the abolishment of AUG, but also the truncation of viral UTR, affects the expression of Gn protein by the RVFV M-segment. PMID:27231931

  18. Enhanced Detection of Rift Valley Fever Virus using Molecular Assays on Whole Blood Samples

    PubMed Central

    Grolla, Allen; Mehedi, Masfique; Lindsay, Robbin; Bosio, Catharine; Duse, Adriano; Feldmann, Heinz

    2012-01-01

    Background Rift Valley fever (RVF) is an emerging arthropod-borne zoonoses of global agricultural and public health importance. In December 2006, an RVF outbreak was recognized in Kenya which led to the deployment of international response laboratory teams to the area. Objectives A field laboratory was operated in Malindi, Kenya to provide safe sample handling and molecular testing for RVF virus (RVFV) as well as selected other pathogens for differential diagnosis. Study Design Safe sample handling was carried out using a negative pressure flexible film isolator (glovebox) and commercial reagents to inactivate clinical specimens and purify nucleic acid. Whole blood was routinely used for diagnostic testing although paired plasma samples were also tested in select cases. Subsequently, human macrophages were tested in vitro for their susceptibility to RVFV. Results The field laboratory received samples from 33 individuals and a definite laboratory diagnosis was provided in 16 of these cases. Using molecular diagnostic techniques, RVFV was more consistently detected in whole blood than in plasma samples most likely due to association of RVFV with blood cells. Subsequent in vitro studies identified macrophages as a target cell for RVFV replication. Conclusions RVFV appears to replicate in blood cells such as macrophages. Thus, the sensitivity of molecular diagnostic testing is improved if whole blood is used as the clinical specimen rather than plasma or serum. PMID:22632901

  19. Bovine trypanosomosis and Glossina distribution in selected areas of southern part of Rift Valley, Ethiopia.

    PubMed

    Sheferaw, Desie; Birhanu, Belay; Asrade, Biruhtesfa; Abera, Mesele; Tusse, Turist; Fikadu, Amha; Denbarga, Yifat; Gona, Zemedkun; Regassa, Alemayehu; Moje, Nebyou; Kussito, Engida; Mekibib, Berhanu; Asefa, Teshome; Woldesenbet, Zerihun

    2016-02-01

    Cross-sectional study was conducted in 9 selected districts of the southern part the Rift Valley, Ethiopia to estimate the dry period prevalence of bovine trypanosomosis as well as assessment of Glossina species. From a total of 1838 cattle examined for trypanosomosis by buffy coat technique 133 (7.2%) were found infected by trypanosome species. From the total positive animals 66.9 and 33.1% of them accounted to Trypanosoma congolense and Trypanosoma vivax, respectively. Significantly higher prevalence (19.4%., P<0.05) was recorded at Arba-Mnch district. Black colored cattle were the most highly affected (χ(2)=79.35, P<0.05) animals. The overall average PCV value for parasitaemic and aparasitaemic animals was 22.2 (95% CI=21.6-22.7) and 27% (95% CI=26.8-27.2), respectively. The fly caught per trap per day was 1.4 for Glossina species and 2.8 for other biting flies. Two species of Glossina identified namely Glossina pallidipes and Glossina fuscipes. PMID:26581831

  20. Rift Valley Fever Virus Epidemic in Kenya, 2006/2007: The Entomologic Investigations

    PubMed Central

    Sang, Rosemary; Kioko, Elizabeth; Lutomiah, Joel; Warigia, Marion; Ochieng, Caroline; O'Guinn, Monica; Lee, John S.; Koka, Hellen; Godsey, Marvin; Hoel, David; Hanafi, Hanafi; Miller, Barry; Schnabel, David; Breiman, Robert F.; Richardson, Jason

    2010-01-01

    In December 2006, Rift Valley fever (RVF) was diagnosed in humans in Garissa Hospital, Kenya and an outbreak reported affecting 11 districts. Entomologic surveillance was performed in four districts to determine the epidemic/epizootic vectors of RVF virus (RVFV). Approximately 297,000 mosquitoes were collected, 164,626 identified to species, 72,058 sorted into 3,003 pools and tested for RVFV by reverse transcription-polymerase chain reaction. Seventy-seven pools representing 10 species tested positive for RVFV, including Aedes mcintoshi/circumluteolus (26 pools), Aedes ochraceus (23 pools), Mansonia uniformis (15 pools); Culex poicilipes, Culex bitaeniorhynchus (3 pools each); Anopheles squamosus, Mansonia africana (2 pools each); Culex quinquefasciatus, Culex univittatus, Aedes pembaensis (1 pool each). Positive Ae. pembaensis, Cx. univittatus, and Cx. bitaeniorhynchus was a first time observation. Species composition, densities, and infection varied among districts supporting hypothesis that different mosquito species serve as epizootic/epidemic vectors of RVFV in diverse ecologies, creating a complex epidemiologic pattern in East Africa. PMID:20682903

  1. HIV type 1 gag genetic diversity among antenatal clinic attendees in North Rift Valley, Kenya.

    PubMed

    Nyagaka, Benuel; Kiptoo, Michael K; Lihana, Raphael W; Khamadi, Samoel A; Makokha, Ernest P; Kinyua, Joyceline G; Mwangi, Joseph; Osman, Saida; Lagat, Nancy J; Muriuki, Joseph; Okoth, Vincent; Gicheru, Michael; Ng'ang'a, Zipporah; Songok, Elijah M

    2012-05-01

    HIV genetic recombination and high mutation rate increase diversity allowing it to escape from host immune response or antiretroviral drugs. This diversity has enabled specific viral subtypes to be predominant in specific regions. To determine HIV-1 subtypes among seropositive antenatal clinic attendees in Kenya's North Rift Valley, a cross-sectional study was carried out on 116 HIV-1-positive blood samples. Proviral DNA was extracted from peripheral blood mononuclear cells by DNAzol lysis and ethanol precipitation. Polymerase chain reactions using specific primers for HIV-1 gag and population sequencing on resulting amplicons were carried out. Phylogenetic analysis revealed that 81 (70%) were subtype A1, 13 (11%) subtype D, 8 (7%) subtype C, 3 (3%) subtype A2, 1 (1%) subtype G, and 10 showed possible recombinants: 5 (4%) subtype A1D, 4 (3%) subtype A1C, and 1 (1%) subtype A2C. These data support the need to establish circulating subtypes for better evaluation of effective HIV diagnostic and treatment options in Kenya. PMID:21827277

  2. Modeling the impact of climate change on the dynamics of Rift Valley Fever.

    PubMed

    Mpeshe, Saul C; Luboobi, Livingstone S; Nkansah-Gyekye, Yaw

    2014-01-01

    A deterministic SEIR model of rift valley fever (RVF) with climate change parameters was considered to compute the basic reproduction number ℛ 0 and investigate the impact of temperature and precipitation on ℛ 0. To study the effect of model parameters to ℛ 0, sensitivity and elasticity analysis of ℛ 0 were performed. When temperature and precipitation effects are not considered, ℛ 0 is more sensitive to the expected number of infected Aedes spp. due to one infected livestock and more elastic to the expected number of infected livestock due to one infected Aedes spp. When climatic data are used, ℛ 0 is found to be more sensitive and elastic to the expected number of infected eggs laid by Aedes spp. via transovarial transmission, followed by the expected number of infected livestock due to one infected Aedes spp. and the expected number of infected Aedes spp. due to one infected livestock for both regions Arusha and Dodoma. These results call for attention to parameters regarding incubation period, the adequate contact rate of Aedes spp. and livestock, the infective periods of livestock and Aedes spp., and the vertical transmission in Aedes species. PMID:24795775

  3. Inhibition of Rift Valley Fever Virus Replication and Perturbation of Nucleocapsid-RNA Interactions by Suramin

    PubMed Central

    Ellenbecker, Mary; Lanchy, Jean-Marc

    2014-01-01

    Rift Valley fever virus (RVFV) is an emerging infectious pathogen that causes severe disease in humans and livestock and has the potential for global spread. There are currently no proven safe and effective treatment options for RVFV infection. Inhibition of RNA binding to RVFV nucleocapsid protein (N) represents an attractive antiviral therapeutic strategy because several essential steps in the RVFV replication cycle involve N binding to viral RNA. In this study, we demonstrate the therapeutic potential of the drug suramin by showing that it functions well as an inhibitor of RVFV replication at multiple stages in human cell culture. Suramin has been used previously to treat trypanosomiasis in Africa. We characterize the dynamic and cooperative nature of N-RNA binding interactions and the dissociation of high-molecular-mass ribonucleoprotein complexes using suramin, which we previously identified as an N-RNA binding inhibitor in a high-throughput screen. Finally, we elucidate the molecular mechanism used by suramin in vitro to disrupt both specific and nonspecific binding events important for ribonucleoprotein formation. PMID:25267680

  4. Has Rift Valley fever virus evolved with increasing severity in human populations in East Africa?

    PubMed

    Baba, Marycelin; Masiga, Daniel K; Sang, Rosemary; Villinger, Jandouwe

    2016-01-01

    Rift Valley fever (RVF) outbreaks have occurred across eastern Africa from 1912 to 2010 approximately every 4-15 years, most of which have not been accompanied by significant epidemics in human populations. However, human epidemics during RVF outbreaks in eastern Africa have involved 478 deaths in 1998, 1107 reported cases with 350 deaths from 2006 to 2007 and 1174 cases with 241 deaths in 2008. We review the history of RVF outbreaks in eastern Africa to identify the epidemiological factors that could have influenced its increasing severity in humans. Diverse ecological factors influence outbreak frequency, whereas virus evolution has a greater impact on its virulence in hosts. Several factors could have influenced the lack of information on RVF in humans during earlier outbreaks, but the explosive nature of human RVF epidemics in recent years mirrors the evolutionary trend of the virus. Comparisons between isolates from different outbreaks have revealed an accumulation of genetic mutations and genomic reassortments that have diversified RVF virus genomes over several decades. The threat to humans posed by the diversified RVF virus strains increases the potential public health and socioeconomic impacts of future outbreaks. Understanding the shifting RVF epidemiology as determined by its evolution is key to developing new strategies for outbreak mitigation and prevention of future human RVF casualties. PMID:27329846

  5. Respiratory infectivity of a recently isolated Egyptian strain of Rift Valley fever virus.

    PubMed Central

    Brown, J L; Dominik, J W; Morrissey, R L

    1981-01-01

    The respiratory infectivity of a strain of Rift Valley fever virus isolated in Egypt (strain ZH-501) was compared with that of one isolate from Uganda (Entebbe strain) and two isolates from South Africa (strains SA-51 and SA-75). Studies were performed with ICR mice which were infected by exposure to infectious aerosols composed of particles with a mass median diameter of 0.96 micrometer. The respiratory median lethal doses for ZH-501, Entebbe, SA-51, and SA-75 were 2.2, 1.9, 2.6, and 1.9 log10 plaque-forming units, respectively. Although these values are statistically different, the biological implications of such differences seem unimportant. In an additional study of pathogenesis, a single group of mice was infected with 3.1 log10 plaque-forming units of ZH-501, and tissues were assayed sequentially through 96 h postinfection. Between 6 and 30 h, demonstration of an increasing virus concentration only in the lungs indicated that initial replication occurred there; however, determination of histopathological changes did not reveal evidence of pneumonia. Virus was isolated from the liver by 48 h, and the ultimate outcome of infection was a fulminating and fatal hepatic necrosis. PMID:7287187

  6. The role of signal transducer and activator of transcription 3 in Rift Valley fever virus infection.

    PubMed

    Pinkham, Chelsea; An, Soyeon; Lundberg, Lindsay; Bansal, Neha; Benedict, Ashwini; Narayanan, Aarthi; Kehn-Hall, Kylene

    2016-09-01

    Rift Valley fever (RVF) is a zoonotic disease that can cause severe illness in humans and livestock, triggering spontaneous abortion in almost 100% of pregnant ruminants. In this study, we demonstrate that signal transducer and activator of transcription 3 (STAT3) is phosphorylated on its conserved tyrosine residue (Y705) following RVFV infection. This phosphorylation was dependent on a major virulence factor, the viral nonstructural protein NSs. Loss of STAT3 had little effect on viral replication, but rather resulted in cells being more susceptible to RVFV-induced cell death. Phosphorylated STAT3 translocated to the nucleus, coinciding with inhibition of fos, jun, and nr4a2 gene expression, and the presence of STAT3 and NSs at the nr4a2 promoter. NSs was found predominantly in the cytoplasm of STAT3 null cells, indicating that STAT3 influences NSs nuclear localization. Collectively, these data demonstrate that STAT3 functions in a pro-survival capacity through modulation of NSs localization. PMID:27318793

  7. The transmission potential of Rift Valley fever virus among livestock in the Netherlands: a modelling study

    PubMed Central

    2013-01-01

    Abstracts Rift Valley fever virus (RVFV) is a zoonotic vector-borne infection and causes a potentially severe disease. Many mammals are susceptible to infection including important livestock species. Although currently confined to Africa and the near-East, this disease causes concern in countries in temperate climates where both hosts and potential vectors are present, such as the Netherlands. Currently, an assessment of the probability of an outbreak occurring in this country is missing. To evaluate the transmission potential of RVFV, a mathematical model was developed and used to determine the initial growth and the Floquet ratio, which are indicators of the probability of an outbreak and of persistence in a periodic changing environment caused by seasonality. We show that several areas of the Netherlands have a high transmission potential and risk of persistence of the infection. Counter-intuitively, these are the sparsely populated livestock areas, due to the high vector-host ratios in these areas. Culex pipiens s.l. is found to be the main driver of the spread and persistence, because it is by far the most abundant mosquito. Our investigation underscores the importance to determine the vector competence of this mosquito species for RVFV and its host preference. PMID:23876054

  8. Inflammatory Biomarkers Associated with Lethal Rift Valley Fever Encephalitis in the Lewis Rat Model

    PubMed Central

    Caroline, Amy L.; Kujawa, Michael R.; Oury, Tim D.; Reed, Douglas S.; Hartman, Amy L.

    2016-01-01

    Rift Valley fever (RVF) is an emerging viral disease that causes significant human and veterinary illness in Africa and the Arabian Peninsula. Encephalitis is one of the severe complications arising from RVF virus (RVFV) infection of people, and the pathogenesis of this form of RVF is completely unknown. We use a novel reproducible encephalitic disease model in rats to identify biomarkers of lethal infection. Lewis rats were infected with RVFV strain ZH501 by aerosol exposure, then sacrificed daily to determine the course of infection and evaluation of clinical, virological, and immunological parameters. Weight loss, fever, and clinical signs occurred during the last 1–2 days prior to death. Prior to onset of clinical indications of disease, rats displayed marked granulocytosis and thrombocytopenia. In addition, high levels of inflammatory chemokines (MCP-1, MCS-F, Gro/KC, RANTES, and IL-1β) were detected first in serum (3–5 dpi) followed by brain (5–7 dpi). The results of this study are consistent with clinical data from human RVF patients and validate Lewis rats as an appropriate small animal model for RVF encephalitis. The biomarkers we identified here will be useful in future studies evaluating the efficacy of novel vaccines and therapeutics. PMID:26779164

  9. A Fusion-Inhibiting Peptide against Rift Valley Fever Virus Inhibits Multiple, Diverse Viruses

    PubMed Central

    Koehler, Jeffrey W.; Smith, Jeffrey M.; Ripoll, Daniel R.; Spik, Kristin W.; Taylor, Shannon L.; Badger, Catherine V.; Grant, Rebecca J.; Ogg, Monica M.; Wallqvist, Anders; Guttieri, Mary C.; Garry, Robert F.; Schmaljohn, Connie S.

    2013-01-01

    For enveloped viruses, fusion of the viral envelope with a cellular membrane is critical for a productive infection to occur. This fusion process is mediated by at least three classes of fusion proteins (Class I, II, and III) based on the protein sequence and structure. For Rift Valley fever virus (RVFV), the glycoprotein Gc (Class II fusion protein) mediates this fusion event following entry into the endocytic pathway, allowing the viral genome access to the cell cytoplasm. Here, we show that peptides analogous to the RVFV Gc stem region inhibited RVFV infectivity in cell culture by inhibiting the fusion process. Further, we show that infectivity can be inhibited for diverse, unrelated RNA viruses that have Class I (Ebola virus), Class II (Andes virus), or Class III (vesicular stomatitis virus) fusion proteins using this single peptide. Our findings are consistent with an inhibition mechanism similar to that proposed for stem peptide fusion inhibitors of dengue virus in which the RVFV inhibitory peptide first binds to both the virion and cell membranes, allowing it to traffic with the virus into the endocytic pathway. Upon acidification and rearrangement of Gc, the peptide is then able to specifically bind to Gc and prevent fusion of the viral and endocytic membranes, thus inhibiting viral infection. These results could provide novel insights into conserved features among the three classes of viral fusion proteins and offer direction for the future development of broadly active fusion inhibitors. PMID:24069485

  10. Organochlorine pesticides in bird species and their prey (fish) from the Ethiopian Rift Valley region, Ethiopia.

    PubMed

    Yohannes, Yared Beyene; Ikenaka, Yoshinori; Nakayama, Shouta M M; Ishizuka, Mayumi

    2014-09-01

    Organochlorine pesticides (OCPs) and stable isotopes were measured in muscle from 4 bird and 5 fish species from the Ethiopian Rift Valley region where DDT is used for malaria control and vast agricultural activities are carried out. We investigated the bioaccumulation of OCPs such as DDTs, HCHs, chlordanes, and heptachlors between the species, and examined the potential risk posed by these compounds for bird species. Significant differences in contaminant profiles and levels were observed within the species. Levels of total OCPs ranged from 3.7 to 148.7 μg/g lipid in bird and 0.04 to 10.9 μg/g lipid in fish species. DDTs were the predominant contaminant, and a positive relationship between δ(15)N and ΣDDT concentrations was found. The main DDT metabolite, p,p'-DDE was the most abundant and significantly greater concentrations in bird species (up to 138.5 μg/g lipid), which could have deleterious effects on survival and/or reproduction of birds. PMID:24907858

  11. Has Rift Valley fever virus evolved with increasing severity in human populations in East Africa?

    PubMed Central

    Baba, Marycelin; Masiga, Daniel K; Sang, Rosemary; Villinger, Jandouwe

    2016-01-01

    Rift Valley fever (RVF) outbreaks have occurred across eastern Africa from 1912 to 2010 approximately every 4–15 years, most of which have not been accompanied by significant epidemics in human populations. However, human epidemics during RVF outbreaks in eastern Africa have involved 478 deaths in 1998, 1107 reported cases with 350 deaths from 2006 to 2007 and 1174 cases with 241 deaths in 2008. We review the history of RVF outbreaks in eastern Africa to identify the epidemiological factors that could have influenced its increasing severity in humans. Diverse ecological factors influence outbreak frequency, whereas virus evolution has a greater impact on its virulence in hosts. Several factors could have influenced the lack of information on RVF in humans during earlier outbreaks, but the explosive nature of human RVF epidemics in recent years mirrors the evolutionary trend of the virus. Comparisons between isolates from different outbreaks have revealed an accumulation of genetic mutations and genomic reassortments that have diversified RVF virus genomes over several decades. The threat to humans posed by the diversified RVF virus strains increases the potential public health and socioeconomic impacts of future outbreaks. Understanding the shifting RVF epidemiology as determined by its evolution is key to developing new strategies for outbreak mitigation and prevention of future human RVF casualties. PMID:27329846

  12. Mapping a Major Gene for Resistance to Rift Valley Fever Virus in Laboratory Rats.

    PubMed

    Busch, Catherine M; Callicott, Ralph J; Peters, Clarence J; Morrill, John C; Womack, James E

    2015-01-01

    The Rift Valley Fever virus (RVFV) presents an epidemic and epizootic threat in sub-Saharan Africa, Egypt, and the Arabian Peninsula, and has furthermore recently gained attention as a potential weapon of bioterrorism due to its ability to infect both livestock and humans. Inbred rat strains show similar characteristic responses to the disease as humans and livestock, making them a suitable model species. Previous studies had indicated differences in susceptibility to RVFV hepatic disease among various rat strains, including a higher susceptibility of Wistar-Furth (WF) compared to a more resistant Lewis (LEW) strain. Further study revealed that this resistance trait exhibits the pattern of a major dominant gene inherited in Mendelian fashion. A genome scan of a congenic WF.LEW strain, created from the susceptible WF and resistant LEW strains and itself resistant to infection with RVFV, revealed 2 potential regions for the location of the gene, 1 on chromosome 3 and the other on chromosome 9. Through backcrossing of WF.LEW rats to WF rats, genotyping offspring using SNPs and microsatellites, and viral challenges of 3 N1 litters, we have mapped the gene to the distal end of chromosome 3. PMID:26546799

  13. Mutational Analysis of the Rift Valley Fever Virus Glycoprotein Precursor Proteins for Gn Protein Expression.

    PubMed

    Phoenix, Inaia; Lokugamage, Nandadeva; Nishiyama, Shoko; Ikegami, Tetsuro

    2016-01-01

    The Rift Valley fever virus (RVFV) M-segment encodes the 78 kD, NSm, Gn, and Gc proteins. The 1st AUG generates the 78 kD-Gc precursor, the 2nd AUG generates the NSm-Gn-Gc precursor, and the 3rd AUG makes the NSm'-Gn-Gc precursor. To understand biological changes due to abolishment of the precursors, we quantitatively measured Gn secretion using a reporter assay, in which a Gaussia luciferase (gLuc) protein is fused to the RVFV M-segment pre-Gn region. Using the reporter assay, the relative expression of Gn/gLuc fusion proteins was analyzed among various AUG mutants. The reporter assay showed efficient secretion of Gn/gLuc protein from the precursor made from the 2nd AUG, while the removal of the untranslated region upstream of the 2nd AUG (AUG2-M) increased the secretion of the Gn/gLuc protein. Subsequently, recombinant MP-12 strains encoding mutations in the pre-Gn region were rescued, and virological phenotypes were characterized. Recombinant MP-12 encoding the AUG2-M mutation replicated slightly less efficiently than the control, indicating that viral replication is further influenced by the biological processes occurring after Gn expression, rather than the Gn abundance. This study showed that, not only the abolishment of AUG, but also the truncation of viral UTR, affects the expression of Gn protein by the RVFV M-segment. PMID:27231931

  14. Elevated Antibodies against Rift Valley Fever Virus among Humans with Exposure to Ruminants in Saudi Arabia

    PubMed Central

    Memish, Ziad A.; Masri, Malak A.; Anderson, Benjamin D.; Heil, Gary L.; Merrill, Hunter R.; Khan, Salah U.; Alsahly, Ahmad; Gray, Gregory C.

    2015-01-01

    In 2000, an outbreak of Rift Valley fever virus (RVFV) occurred in the Kingdom of Saudi Arabia (KSA). Since then there have been sparse efforts to monitor for RVFV reemergence. During 2012, we enrolled 300 individuals with ruminant exposure and 50 age-group matched non-exposed controls in southwestern KSA, in a cross-sectional epidemiological study of RVFV. Sera from the participants were screened with an enzyme-linked immunosorbent assay (ELISA) for anti-RVFV IgG antibodies of which 39 (11.1%) were positive. Sixteen (41.0%) of those 39 were also positive by a plaque reduction neutralization assay (PRNT). The PRNT-positive subjects were further studied with an IgM ELISA and one was positive. No RVFV was detected in the 350 sera using real-time reverse transcription polymerase chain reaction. Contact with cattle (odds ratio [OR] = 3.16, 95% confidence interval [CI] 1.01, 9.90) and a history of chronic medical illness (OR = 6.41, 95% CI 1.75, 23.44) were associated with greater odds of RVFV seropositivity by PRNT. The IgM-positive participant was 36 years of age, and reported multiple risk factors for ruminant contact. Although these findings simply may be vestiges of the 2000 epidemic, KSA's frequent visits from pilgrims and importations of live animals from RVFV-endemic areas suggest that more comprehensive surveillance for imported RVFV virus in ruminants, mosquitoes, and travelers is imperative. PMID:25646253

  15. Potential for mosquitoes (Diptera: Culicidae) from Florida to transmit Rift Valley fever virus.

    PubMed

    Turell, Michael J; Britch, Seth C; Aldridge, Robert L; Kline, Daniel L; Boohene, Carl; Linthicum, Kenneth J

    2013-09-01

    We evaluated Aedes atlanticus Dyar and Knab, Aedes infirmatus Dyar and Knab, Aedes vexans (Meigen), Anopheles crucians Wiedemann, Coquillettidia perturbans (Walker), Culex nigripalpus Theobald, Mansonia dyari Belkin, Heinemann, and Page, and Psorophora ferox (Von Humboldt) from Florida to determine which of these species should be targeted for control should Rift Valley fever virus (RVFV) be detected in North America. Female mosquitoes that had fed on adult hamsters inoculated with RVFV were incubated for 7-21 d at 26 degrees C, then allowed to refeed on susceptible hamsters, and tested to determine infection, dissemination, and transmission rates. We also inoculated mosquitoes intrathoracically, held them for 7 d, and then allowed them to feed on a susceptible hamster to check for a salivary gland barrier. When exposed to hamsters with viremias > or = 10(7.6) plaque-forming units per milliliter of blood, at least some individuals in each of the species tested became infected; however, Cx. nigripalpus, An. crucians, and Ae. infirmatus were essentially incompetent vectors in the laboratory because of either a midgut escape or salivary gland barrier. Each of the other species should be considered as potential vectors and would need to be controlled if RVFV were introduced into an area where they were found. Additional studies need to be conducted with other geographic populations of these species and to determine how environmental factors affect transmission. PMID:24180117

  16. Serologic evidence of exposure to Rift Valley fever virus detected in Tunisia

    PubMed Central

    Bosworth, A.; Ghabbari, T.; Dowall, S.; Varghese, A.; Fares, W.; Hewson, R.; Zhioua, E.; Chakroun, M.; Tiouiri, H.; Ben Jemaa, M.; Znazen, A.; Letaief, A.

    2015-01-01

    Rift Valley fever virus (RVFv) is capable of causing dramatic outbreaks amongst economically important animal species and is capable of causing severe symptoms and mortality in humans. RVFv is known to circulate widely throughout East Africa; serologic evidence of exposure has also been found in some northern African countries, including Mauritania. This study aimed to ascertain whether RVFv is circulating in regions beyond its known geographic range. Samples from febrile patients (n = 181) and nonfebrile healthy agricultural and slaughterhouse workers (n = 38) were collected during the summer of 2014 and surveyed for exposure to RVFv by both serologic tests and PCR. Of the 219 samples tested, 7.8% of nonfebrile participants showed immunoglobulin G reactivity to RVFv nucleoprotein and 8.3% of febrile patients showed immunoglobulin M reactivity, with the latter samples indicating recent exposure to the virus. Our results suggest an active circulation of RVFv and evidence of human exposure in the population of Tunisia. PMID:26740887

  17. Development and characterization of Rift Valley fever virus-like particles.

    PubMed

    Li, Y T; Wang, C L; Zheng, X X; Wang, H L; Zhao, Y K; Gai, W W; Jin, H L; Gao, Y W; Li, N; Yang, S T; Xia, X Z

    2016-01-01

    Rift Valley fever (RVF) is an acute, febrile zoonotic disease that is caused by the RVF virus (RVFV) and spread by arthropod vectors. RVF is currently prevalent in Africa and the Arabian Peninsula, and causes substantial economic losses. Furthermore, this disease poses a serious threat to animal and human health in regions worldwide, making it a serious public health concern. However, RVFV vaccines for human use are still unavailable, and hence there is an urgent need for novel efficient vaccines against RVFV. Vaccine preparation techniques have become a crucial factor in developing new vaccines. In the current study, the N and G protein genes of RVFV were inserted into the pFastBacDual baculovirus expression vector downstream of the pP10 and pPH promoters. The resultant recombinant vector, pFastBacDual-S-M, was transfected into Sf9 insect cells by lipofection. The recombinant baculovirus, named rBac-N-G, was retrieved and infected into Sf9 insect cells to generate RVFV virus-like particles (VLPs). Using polyclonal antibodies against RVFV proteins in immunofluorescence and western blot analyses, we positively identified the presence of the RVFV proteins in VLP preparations. Sucrose density gradient centrifugation and transmission electron microscopy revealed that the morphology of the RVFV VLPs was consistent with previous reports of RVFV virions. This study describes a technique for efficient production of RVFV VLPs, and has laid the foundation for future VLP-based RVFV vaccines. PMID:27050999

  18. Surveillance of Rift Valley Fever Virus in Mosquito Vectors of the Republic of Korea.

    PubMed

    Kim, Hyun-Joo; Lyoo, Hye-Rhyoung; Park, Jee-Yong; Choi, Jeong-Soo; Lee, Ji-Youn; Jeoung, Hye-Young; Cho, Yun-Sang; Cho, In-Soo; Yoo, Han Sang

    2016-02-01

    Rift Valley fever (RVF) is an acute mosquito-borne viral zoonotic disease that affects mainly domestic ruminants and humans. RVF virus (RVFV) was first identified in Kenya in 1931 and was reported to be endemic in Africa but has recently spread to the Arabian Peninsula. With increasing climate change and globalization of trade in animals and animal products, there is great concern that the disease will spread worldwide to regions such as Europe, Asia, and the Americas. Although RVFV has not been reported in the Republic of Korea (ROK), the possibility of RVFV introduction is increasing because transmissible mosquito vectors are present and direct flights to Africa were added in 2012. For these reasons, we conducted a surveillance study to detect RVFV in mosquito vectors collected around the airport and harbor from 2012 to 2013. A total of 36,734 mosquitoes were collected and tested by real-time RT-PCR. A total of 1837 mosquito pools were used, and all were confirmed to be negative. This is the first report in the ROK concerning RVFV surveillance in mosquito vectors, and continuous surveillance will be conducted for the early warning of RVFV introduction. PMID:26771529

  19. A preliminary evaluation of the DDT contamination of sediments in lakes Natron and Bogoria (Eastern Rift Valley, Africa).

    PubMed

    Bettinetti, Roberta; Quadroni, Silvia; Crosa, Giuseppe; Harper, David; Dickie, Jennifer; Kyalo, Margaret; Mavuti, Kenneth; Galassi, Silvana

    2011-06-01

    Dichlorodiphenyltrichloroethane (DDT) is still used in Africa for the indoor control of malaria and it may represent a potential hazard for wildlife. The littoral sediments of two alkaline-saline lakes, Natron (Tanzania) and Bogoria (Kenya), in the Eastern Rift Valley, supporting large populations of lesser flamingos (Phoeniconaias minor), were analysed for DDT residues. Physical-chemical analyses (temperature, conductivity, pH and dissolved oxygen) were also performed on the water of the two lakes and in the tributaries of Lake Natron, to evaluate the influence of the environmental variables on pollutant occurrence. At Lake Natron, around 1 km from the sediment collection sites, tree leaves of Acacia tortilis were also collected. The main metabolite found in all sediment samples was pp'DDE, whilst equal concentrations of pp'DDT and pp'DDE were measured in acacia leaves. The levels of DDTs measured in the sediments were within 5.9-30.9 ng g(-1) d.w., reaching the maximum value in a tributary of Lake Natron. On the whole, the contamination of Lake Natron and Lake Bogoria basins seems to be quite moderate. Nevertheless, the pp'DDE/pp'DDT ratio equals 1 in the Acacia tortilis leaves, which makes one suppose that the input of the parent compound was rather recent and could have been from aerial transport or dust from relatively close-by old pesticides storage sites. PMID:21809777

  20. The risk of Rift Valley fever virus introduction and establishment in the United States and European Union

    PubMed Central

    Rolin, Alicia I; Berrang-Ford, Lea; Kulkarni, Manisha A

    2013-01-01

    Rift Valley fever virus (RVFV) is an arthropod-borne disease resulting in severe morbidity and mortality in both human and ruminant populations. First identified in Kenya in 1930, the geographical range of RVFV has been largely constrained to the African continent, yet has recently spread to new regions, and is identified as a priority disease with potential for geographic emergence. We present a systematic literature review assessing the potential for RVFV introduction and establishment in the United States (US) and European Union (EU). Viable pathways for the introduction of RVFV include: transport of virus-carrying vectors, importation of viremic hosts and intentional entry of RVFV as a biological weapon. It is generally assumed that the risk of RVFV introduction into the US or EU is low. We argue that the risk of sporadic introduction is likely high, though currently an insufficient proportion of such introductions coincide with optimal environmental conditions. Future global trends may increase the likelihood of risk factors for RVFV spread. PMID:26038446

  1. Inter-epidemic Acquisition of Rift Valley Fever Virus in Humans in Tanzania

    PubMed Central

    Sumaye, Robert David; Abatih, Emmanuel Nji; Thiry, Etienne; Amuri, Mbaraka; Berkvens, Dirk; Geubbels, Eveline

    2015-01-01

    Background In East Africa, epidemics of Rift Valley fever (RVF) occur in cycles of 5–15 years following unusually high rainfall. RVF transmission during inter-epidemic periods (IEP) generally passes undetected in absence of surveillance in mammalian hosts and vectors. We studied IEP transmission of RVF and evaluated the demographic, behavioural, occupational and spatial determinants of past RVF infection. Methodology Between March and August 2012 we collected blood samples, and administered a risk factor questionnaire among 606 inhabitants of 6 villages in the seasonally inundated Kilombero Valley, Tanzania. ELISA tests were used to detect RVFV IgM and IgG antibodies in serum samples. Risk factors were examined by mixed effects logistic regression. Findings RVF virus IgM antibodies, indicating recent RVFV acquisition, were detected in 16 participants, representing 2.6% overall and in 22.5% of inhibition ELISA positives (n = 71). Four of 16 (25.0%) IgM positives and 11/71 (15.5%) of individuals with inhibition ELISA sero-positivity reported they had had no previous contact with host animals. Sero-positivity on inhibition ELISA was 11.7% (95% CI 9.2–14.5) and risk was elevated with age (odds ratio (OR) 1.03 per year; 95% CI 1.01–1.04), among milkers (OR 2.19; 95% CI 1.23–3.91), and individuals eating raw meat (OR 4.17; 95% CI 1.18–14.66). Households keeping livestock had a higher probability of having members with evidence of past infection (OR = 3.04, 95% CI = 1.42–6.48) than those that do not keep livestock. Conclusion There is inter-epidemic acquisition of RVFV in Kilombero Valley inhabitants. In the wake of declining malaria incidence, these findings underscore the need for clinicians to consider RVF in the differential diagnosis for febrile illnesses. Several types of direct contact with livestock are important risk factors for past infection with RVFV in this study’s population. However, at least part of RVFV transmission appears to have occurred

  2. Molecular genetic analyses of historical lake sediments from the East African Rift Valley

    NASA Astrophysics Data System (ADS)

    Epp, L. S.; Stoof, K.; Trauth, M. H.; Tiedemann, R.

    2009-04-01

    Ancient DNA research, especially that of environmental samples, has to date focussed mainly on samples obtained from colder regions, owing to better DNA preservation. We explored the potential of using ancient DNA from sediments and sediment cores of shallow lakes in Kenya. These lakes, located in the eastern branch of the East African Rift Valley, are in close proximity, yet display strikingly different hydrological and geological features. Present day lakes range in alkalinity from pH 11 (Lake Elmenteita) to pH 8 (Lake Naivasha), and in depth from less than one meter to 15 meters. Historically they have undergone a number of drastic changes in lake level and environmental conditions, both on geological timescales and during the last centuries. Within this setting we employed molecular genetic methods to study DNA from recent and historic lake sediments, focussing on rotifers and diatoms. We analyzed population and species succession in the alkaline-saline crater lake Sonachi since the beginning of the 19th century, as well as distributions in recent and historic sediments of other lakes of the East African Rift System. To specifically detect diatoms, we developed a protocol using taxon-specific polymerase chain reactions and separation of products by denaturing high performance liquid chromatography (DHPLC). Employing this protocol we retrieved "ancient" DNA from a number of taxonomically diverse organisms, but found diatoms only in sediments younger than approximately 90 years. Using higly specific reactions for rotifers of the genus Brachionus, we tracked species and population succession in Lake Sonachi during the last 200 years. Populations were dominated by a single mitochondrial haplotype for a period of 150 years, and two putatively intraspecific turnovers in dominance occurred. They were both correlated to major environmental changes documented by profound visible changes in sediment composition of the core: the deposition of a volcanic ash and a

  3. Application of polar-orbiting, meteorological satellite data to detect flooding of Rift Valley Fever virus vector mosquito habitats in Kenya.

    PubMed

    Linthicum, K J; Bailey, C L; Tucker, C J; Mitchell, K D; Logan, T M; Davies, F G; Kamau, C W; Thande, P C; Wagateh, J N

    1990-10-01

    Measurements of green-leaf vegetation dynamics recorded by the advanced very high resolution radiometer instruments onboard National Oceanic and Atmospheric Administration satellites 7 and 9 were used to derive ground moisture and rainfall patterns in Kenya and monitor resultant flooding of mosquito larval habitats (dambos) likely to support Rift Valley Fever virus vector mosquitoes (Aedes and Culex spp.). Satellite-derived data from mid-1981 to December 1988 have been analysed with corresponding rainfall, flooding and vector population data as they relate to Rift Valley Fever virus ecology. Single (7 x 7 km) and multiple grid-cell image analysis (200 x 300 km) in small localized areas and large geographical regions, respectively, of vegetation data were used to quantify the potential for flooding of mosquito breeding habitats. The ability to detect accurately parameters, such as ground moisture, that determine flooding could provide local officials with sufficient warning to allow for implementation of specific mosquito control measures before a disease outbreak. PMID:1983457

  4. Surface slip during large Owens Valley earthquakes

    NASA Astrophysics Data System (ADS)

    Haddon, E. K.; Amos, C. B.; Zielke, O.; Jayko, A. S.; Bürgmann, R.

    2016-06-01

    The 1872 Owens Valley earthquake is the third largest known historical earthquake in California. Relatively sparse field data and a complex rupture trace, however, inhibited attempts to fully resolve the slip distribution and reconcile the total moment release. We present a new, comprehensive record of surface slip based on lidar and field investigation, documenting 162 new measurements of laterally and vertically displaced landforms for 1872 and prehistoric Owens Valley earthquakes. Our lidar analysis uses a newly developed analytical tool to measure fault slip based on cross-correlation of sublinear topographic features and to produce a uniquely shaped probability density function (PDF) for each measurement. Stacking PDFs along strike to form cumulative offset probability distribution plots (COPDs) highlights common values corresponding to single and multiple-event displacements. Lateral offsets for 1872 vary systematically from ˜1.0 to 6.0 m and average 3.3 ± 1.1 m (2σ). Vertical offsets are predominantly east-down between ˜0.1 and 2.4 m, with a mean of 0.8 ± 0.5 m. The average lateral-to-vertical ratio compiled at specific sites is ˜6:1. Summing displacements across subparallel, overlapping rupture traces implies a maximum of 7-11 m and net average of 4.4 ± 1.5 m, corresponding to a geologic Mw ˜7.5 for the 1872 event. We attribute progressively higher-offset lateral COPD peaks at 7.1 ± 2.0 m, 12.8 ± 1.5 m, and 16.6 ± 1.4 m to three earlier large surface ruptures. Evaluating cumulative displacements in context with previously dated landforms in Owens Valley suggests relatively modest rates of fault slip, averaging between ˜0.6 and 1.6 mm/yr (1σ) over the late Quaternary.

  5. Comparison of Rift Valley fever virus replication in North American livestock and wildlife cell lines

    PubMed Central

    Gaudreault, Natasha N.; Indran, Sabarish V.; Bryant, P. K.; Richt, Juergen A.; Wilson, William C.

    2015-01-01

    Rift Valley fever virus (RVFV) causes disease outbreaks across Africa and the Arabian Peninsula, resulting in high morbidity and mortality among young domestic livestock, frequent abortions in pregnant animals, and potentially severe or fatal disease in humans. The possibility of RVFV spreading to the United States or other countries worldwide is of significant concern to animal and public health, livestock production, and trade. The mechanism for persistence of RVFV during inter-epidemic periods may be through mosquito transovarial transmission and/or by means of a wildlife reservoir. Field investigations in endemic areas and previous in vivo studies have demonstrated that RVFV can infect a wide range of animals, including indigenous wild ruminants of Africa. Yet no predominant wildlife reservoir has been identified, and gaps in our knowledge of RVFV permissive hosts still remain. In North America, domestic goats, sheep, and cattle are susceptible hosts for RVFV and several competent vectors exist. Wild ruminants such as deer might serve as a virus reservoir and given their abundance, wide distribution, and overlap with livestock farms and human populated areas could represent an important risk factor. The objective of this study was to assess a variety of cell lines derived from North American livestock and wildlife for susceptibility and permissiveness to RVFV. Results of this study suggest that RVFV could potentially replicate in native deer species such as white-tailed deer, and possibly a wide range of non-ruminant animals. This work serves to guide and support future animal model studies and risk model assessment regarding this high-consequence zoonotic pathogen. PMID:26175725

  6. A systematic review of Rift Valley Fever epidemiology 1931–2014

    PubMed Central

    Nanyingi, Mark O.; Munyua, Peninah; Kiama, Stephen G.; Muchemi, Gerald M.; Thumbi, Samuel M.; Bitek, Austine O.; Bett, Bernard; Muriithi, Reese M.; Njenga, M. Kariuki

    2015-01-01

    Background Rift Valley Fever (RVF) is a mosquito-borne viral zoonosis that was first isolated and characterized in 1931 in Kenya. RVF outbreaks have resulted in significant losses through human illness and deaths, high livestock abortions and deaths. This report provides an overview on epidemiology of RVF including ecology, molecular diversity spatiotemporal analysis, and predictive risk modeling. Methodology Using the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, we systematically searched for relevant RVF publications in repositories of the World Health Organization Library and Information Networks for Knowledge (WHOLIS), U.S Centers for Disease Control and Prevention (CDC), and Food and Agricultural Organization (FAO). Detailed searches were performed in Google Scholar, SpringerLink, and PubMed databases and included conference proceedings and books published from 1931 up to 31st January 2015. Results and discussion A total of 84 studies were included in this review; majority (50%) reported on common human and animal risk factors that included consumption of animal products, contact with infected animals and residing in low altitude areas associated with favorable climatic and ecological conditions for vector emergence. A total of 14 (16%) of the publications described RVF progressive spatial and temporal distribution and the use of risk modeling for timely prediction of imminent outbreaks. Using distribution maps, we illustrated the gradual spread and geographical extent of disease; we also estimated the disease burden using aggregate human mortalities and cumulative outbreak periods for endemic regions. Conclusion This review outlines common risk factors for RVF infections over wider geographical areas; it also emphasizes the role of spatial models in predicting RVF enzootics. It, therefore, explains RVF epidemiological status that may be used for design of targeted surveillance and control programs in endemic

  7. Recent outbreaks of rift valley Fever in East Africa and the middle East.

    PubMed

    Himeidan, Yousif E; Kweka, Eliningaya J; Mahgoub, Mostafa M; El Rayah, El Amin; Ouma, Johnson O

    2014-01-01

    Rift Valley fever (RVF) is an important neglected, emerging, mosquito-borne disease with severe negative impact on human and animal health. Mosquitoes in the Aedes genus have been considered as the reservoir, as well as vectors, since their transovarially infected eggs withstand desiccation and larvae hatch when in contact with water. However, different mosquito species serve as epizootic/epidemic vectors of RVF, creating a complex epidemiologic pattern in East Africa. The recent RVF outbreaks in Somalia (2006-2007), Kenya (2006-2007), Tanzania (2007), and Sudan (2007-2008) showed extension to districts, which were not involved before. These outbreaks also demonstrated the changing epidemiology of the disease from being originally associated with livestock, to a seemingly highly virulent form infecting humans and causing considerably high-fatality rates. The amount of rainfall is considered to be the main factor initiating RVF outbreaks. The interaction between rainfall and local environment, i.e., type of soil, livestock, and human determine the space-time clustering of RVF outbreaks. Contact with animals or their products was the most dominant risk factor to transfer the infection to humans. Uncontrolled movement of livestock during an outbreak is responsible for introducing RVF to new areas. For example, the virus that caused the Saudi Arabia outbreak in 2000 was found to be the same strain that caused the 1997-98 outbreaks in East Africa. A strategy that involves active surveillance with effective case management and diagnosis for humans and identifying target areas for animal vaccination, restriction on animal movements outside the affected areas, identifying breeding sites, and targeted intensive mosquito control programs has been shown to succeed in limiting the effect of RVF outbreak and curb the spread of the disease from the onset. PMID:25340047

  8. Evidence of rift valley fever seroprevalence in the Sahrawi semi-nomadic pastoralist system, Western Sahara

    PubMed Central

    2014-01-01

    Background The increasing global importance of Rift Valley fever (RVF) is clearly demonstrated by its geographical expansion. The presence of a wide range of host and vector species, and the epidemiological characteristics of RVF, have led to concerns that epidemics will continue to occur in previously unaffected regions of Africa. The proximity of the Sahrawi territories of Western Sahara to endemic countries, such as Mauritania, Senegal, and Mali with periodic isolation of virus and serological evidence of RVF, and the intensive livestock trade in the region results in a serious risk of RVF spread in the Sahrawi territories, and potentially from there to the Maghreb and beyond. A sero-epidemiological survey was conducted in the Saharawi territories between March and April 2008 to investigate the possible presence of the RVF virus (RVFV) and associated risk factors. A two-stage cluster sampling design was used, incorporating 23 sampling sites. Results A total of 982 serum samples was collected from 461 sheep, 463 goats and 58 camels. Eleven samples (0.97%) tested positive for IgG against the RVFV. There were clusters of high seroprevalence located mostly in the Tifariti (7.69%) and Mehaires (7.14%) regions, with the Tifariti event having been found in one single flock (4/26 positive animals). Goats and older animals were at a significantly increased risk being seropositive (p = 0.007 and p = 0.007, respectively). Conclusion The results suggest potential RVF activity in the study area, where intense livestock movement and trade with neighbouring countries might be considered as a primary determinant in the spread of the disease. The importance of a continuous field investigation is reinforced, in light of the risk of RVF expansion to historically unaffected regions of Africa. PMID:24758592

  9. Breaking the chain: Rift Valley fever virus control via livestock vaccination.

    PubMed

    Bird, Brian H; Nichol, Stuart T

    2012-06-01

    Rift Valley fever virus is a mosquito-borne pathogen of livestock and humans that causes widespread and devastating outbreaks of severe and often fatal disease throughout Africa and portions of the Arabian Peninsula. Outbreaks can involve tens to hundreds of thousands of human cases, and millions of livestock. The severity of the disease varies by species, but in sheep and cattle 'abortion storms', high neonatal (∼70%), and adult mortality (20-30%) are features. Human cases are generally self-limiting, but severe complications such as hepatitis, retinitis, delayed-onset encephalitis, or a hemorrhagic syndrome with a case fatality of 10-20% can occur. There are no commercially available human vaccines. Livestock provide key ecological links between the Aedes sp. mosquito vector and humans. High viremias in livestock lead to spillover of RVFV into other anthrophillic vectors (Culex and Anopheles sp. mosquitoes), and, importantly, close contact with infected animal tissues and fluids or aborted fetal materials from these animals is a major risk factor for severe and lethal human infections. Vaccination programs targeting livestock during non-epidemic periods or as an early countermeasure against nascent outbreaks could therefore eliminate one of the main sources of human infection and limit the overall scope of epidemics. To this end, research groups have recently reported novel next generation RVFV vaccines that are safe for use in pregnant and young animals. Preventing RVFV infection of livestock by vaccination is a key element in breaking the chain of human epidemics, and could lead to control of this significant public health threat. PMID:22463980

  10. Streptomyces alkaliphilus sp. nov., isolated from sediments of Lake Elmenteita in the Kenyan Rift Valley.

    PubMed

    Akhwale, Juliah Khayeli; Göker, Markus; Rohde, Manfred; Spröer, Cathrin; Schumann, Peter; Klenk, Hans-Peter; Boga, Hamadi Iddi

    2015-05-01

    A novel strain, designated No. 7(T), was isolated from a sediment sample collected from the alkaline, saline Lake Elmenteita located in the Kenyan Rift Valley. The optimal growth for the strain was found to be at temperature 30-35 °C, at pH 8.0-12.0 in the presence of 7.0-10.0 % (w/v) NaCl. The strain was observed to form a light green beige abundant aerial mycelium on Horikoshi 1 agar and to have morphological and chemotaxonomic characteristics typical of members of the genus Streptomyces. The peptidoglycan was found to contain LL-diaminopimelic acid as the diamino acid, with no diagnostic sugars identified. The predominant menaquinone was identified as MK-9(H6). The main polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and an unknown phospholipid. Cellular fatty acids were found to consist of saturated branched-chain acids with iso-C(15:0), anteiso-C(15:0), iso-C(16:0) and anteiso-C(17:0) acids predominating. The type strain had a genomic DNA G+C content of 72.8 mol% and formed a distinct phyletic line within the genus Streptomyces. Based on the chemotaxonomic results, 16S rRNA gene sequence analysis and the low DNA-DNA hybridization value with the type strain of Streptomyces calidiresistens, it is proposed that strain No. 7(T) (= DSM 42118 = CECT 8549) represents a novel species, Streptomyces alkaliphilus. The INSDC accession number for the 16S rRNA gene sequence of strain No. 7(T) is KF976730. PMID:25761860

  11. Rift Valley Fever in Humans and Animals in Mayotte, an Endemic Situation?

    PubMed Central

    Jego, Maël; Desprès, Philippe; Collet, Louis; Zumbo, Betty; Tillard, Emmanuel; Girard, Sébastien; Filleul, Laurent

    2013-01-01

    Retrospective studies and surveillance on humans and animals revealed that Rift Valley Fever virus (RVFV) has been circulating on Mayotte for at least several years. A study was conducted in 2011 to estimate the seroprevalence of RVF in humans and in animals and to identify associated risk factors. Using a multistage cluster sampling method, 1420 individuals were enrolled in the human study, including 337 children aged 5 to 14 years. For the animal study, 198 seronegative ruminants from 33 randomly selected sentinel ruminant herds were followed up for more than one year. In both studies, information on environment and risk factors was collected through a standardized questionnaire. The overall weighted seroprevalence of RVFV antibodies in the general population aged ≥5 years was 3.5% (95% CI 2.6–4.8). The overall seroprevalence of RVFV antibodies in the ruminant population was 25.3% (95% CI 19.8–32.2). Age (≥15), gender (men), place of birth on the Comoros, living in Mayotte since less than 5 years, low educational level, farming and living close to a water source were significantly associated with RVFV seropositivity in humans. Major risk factors for RFV infection in animals were the proximity of the farm to a water point, previous two-month rainfall and absence of abortions disposal. Although resulting in few clinical cases in humans and in animals, RVFV has been circulating actively on the island of Mayotte, in a context of regular import of the virus from nearby countries through illegal animal movements, the presence of susceptible animals and a favorable environment for mosquito vectors to maintain virus transmission locally. Humans and animals share the same ways of RVFV transmission, with mosquitoes playing an important role. The studies emphasize the need for a one health approach in which humans and animals within their ecosystems are included. PMID:24098637

  12. Wetland sedimentation and associated diatoms in the Pleistocene Olorgesailie Basin, southern Kenya Rift Valley

    NASA Astrophysics Data System (ADS)

    Owen, R. Bernhart; Renaut, Robin W.; Scott, Jennifer J.; Potts, Richard; Behrensmeyer, Anna K.

    2009-12-01

    The Olorgesailie Basin in the southern Kenya Rift Valley contains a variety of lacustrine, wetland and terrestrial facies that were laid down during the last 1.2 million years. This study integrates diatom, ichnofossil, and rhizolith (silica and carbonate) evidence in order to identify and characterize shallow wetland deposition at the top (Member 14; ca. 493 ka) of the Olorgesailie Formation. A key feature of these deposits is the presence of facies with aquatic indicators (diatoms) that are overprinted by ichnofossils and rhizoliths that suggest drier conditions. Diatom floras include several fresh water Aulacoseira spp. and saline indicators such as Thalassiosirarudolfi, T.faurii, Cyclotellameneghiniana and Anomoeoneissphaerophora. The main indicators of shallow fresh to mildly saline waters include Epithemia argus, Rhopalodiagibberula, Encyonema muelleri, and Synedra spp. Three main suites of ichnofossils indicate varying water table depths during their formation. These consist of 1) horizontal tunnels that suggest saturated substrates; 2) vertical burrows formed in substrates with relatively lower water tables; and 3) termite, hymenopteran, and beetle ichnofossils that indicate dry substrates. Member 14 of the Olorgesailie Formation also contains carbonate and siliceous rhizoliths, which occur both together and separately. Four possible models are suggested to explain the silica and carbonate rhizolith formation: 1) a complex of spring-fed marshes and dry areas; 2) ephemeral wetlands and floodplains; 3) wetlands with abundant organic decay, and 4) initial carbonate rhizoliths that were replaced by silica. Preservation of cellular structures and the reworking and incorporation of rhizoliths in overlying younger strata suggest that they formed early during diagenesis.

  13. Epidemiologic and Environmental Risk Factors of Rift Valley Fever in Southern Africa from 2008 to 2011

    PubMed Central

    Glancey, Margaret M.; Linthicum, Kenneth J.

    2015-01-01

    Abstract Background: Rift Valley fever (RVF) outbreaks have been associated with periods of widespread and above-normal rainfall over several months. Knowledge on the environmental factors influencing disease transmission dynamics has provided the basis for developing models to predict RVF outbreaks in Africa. From 2008 to 2011, South Africa experienced the worst wave of RVF outbreaks in almost 40 years. We investigated rainfall-associated environmental factors in southern Africa preceding these outbreaks. Methods: RVF epizootic records obtained from the World Animal Health Information Database (WAHID), documenting livestock species affected, location, and time, were analyzed. Environmental variables including rainfall and satellite-derived normalized difference vegetation index (NDVI) data were collected and assessed in outbreak regions to understand the underlying drivers of the outbreaks. Results: The predominant domestic vertebrate species affected in 2008 and 2009 were cattle, when outbreaks were concentrated in the eastern provinces of South Africa. In 2010 and 2011, outbreaks occurred in the interior and southern provinces affecting over 16,000 sheep. The highest number of cases occurred between January and April but epidemics occurred in different regions every year, moving from the northeast of South Africa toward the southwest with each progressing year. The outbreaks showed a pattern of increased rainfall preceding epizootics ranging from 9 to 152 days; however, NDVI and rainfall were less correlated with the start of the outbreaks than has been observed in eastern Africa. Conclusions: Analyses of the multiyear RVF outbreaks of 2008 to 2011 in South Africa indicated that rainfall, NDVI, and other environmental and geographical factors, such as land use, drainage, and topography, play a role in disease emergence. Current and future investigations into these factors will be able to contribute to improving spatial accuracy of models to map risk areas

  14. Rainwater harvesting for small-scale irrigation of maize in the Central Rift Valley, Ethiopia

    NASA Astrophysics Data System (ADS)

    Keesstra, Saskia; Hartog, Maaike; Muluneh, Alemayehu; Stroosnijder, Leo

    2013-04-01

    In the Central Rift Valley of Ethiopia, small scale farmers mostly rely on rainfall for crop production. The erratic nature of rainfall causes frequent crop failures and makes the region structurally dependent on food aid. Rainwater Harvesting (RWH) is a technique to collect and store runoff that could provide water for livestock, domestic use or small scale irrigation. Usually, such irrigation is promoted for high value crops, but in the light of regional food security it may become interesting to invest in irrigation of maize. In this research, two cemented RWH cisterns were investigated to determine their economic and social potential for supplemental irrigation of maize using drip irrigation. For this, data from test fields with irrigated maize and monitoring of water levels of the cisterns were used, as well as a survey under 30 farmers living close to the experimental site. The results show that catchment size and management should be in balance with the designed RWH system, to prevent too little runoff or flooding. An analysis with Cropwat 8.0 was used to investigate the possibility of irrigating maize with the observed amounts of water in the RWH cisterns. This would suffice for 0.3-0.8 ha of maize. For a RWH cistern with a drip irrigation system to be economically viable, the production on this acreage should become 3-4 ton/ha; 2.5 times higher than the current yield. But the biggest challenge would be to change the perception of respondents, who don't find it logical to spend precious water on a common crop like maize. Therefore, if the Ethiopian government considers the irrigation of maize to be important for regional food security, it is recommended to either subsidize the construction of RWH cisterns or provide credit on favourable terms.

  15. Predictive Factors and Risk Mapping for Rift Valley Fever Epidemics in Kenya

    PubMed Central

    Munyua, Peninah M.; Murithi, R. Mbabu; Ithondeka, Peter; Hightower, Allen; Thumbi, Samuel M.; Anyangu, Samuel A.; Kiplimo, Jusper; Bett, Bernard; Vrieling, Anton; Breiman, Robert F.; Njenga, M. Kariuki

    2016-01-01

    Background To-date, Rift Valley fever (RVF) outbreaks have occurred in 38 of the 69 administrative districts in Kenya. Using surveillance records collected between 1951 and 2007, we determined the risk of exposure and outcome of an RVF outbreak, examined the ecological and climatic factors associated with the outbreaks, and used these data to develop an RVF risk map for Kenya. Methods Exposure to RVF was evaluated as the proportion of the total outbreak years that each district was involved in prior epizootics, whereas risk of outcome was assessed as severity of observed disease in humans and animals for each district. A probability-impact weighted score (1 to 9) of the combined exposure and outcome risks was used to classify a district as high (score ≥ 5) or medium (score ≥2 - <5) risk, a classification that was subsequently subjected to expert group analysis for final risk level determination at the division levels (total = 391 divisions). Divisions that never reported RVF disease (score < 2) were classified as low risk. Using data from the 2006/07 RVF outbreak, the predictive risk factors for an RVF outbreak were identified. The predictive probabilities from the model were further used to develop an RVF risk map for Kenya. Results The final output was a RVF risk map that classified 101 of 391 divisions (26%) located in 21 districts as high risk, and 100 of 391 divisions (26%) located in 35 districts as medium risk and 190 divisions (48%) as low risk, including all 97 divisions in Nyanza and Western provinces. The risk of RVF was positively associated with Normalized Difference Vegetation Index (NDVI), low altitude below 1000m and high precipitation in areas with solonertz, luvisols and vertisols soil types (p <0.05). Conclusion RVF risk map serves as an important tool for developing and deploying prevention and control measures against the disease. PMID:26808021

  16. Remote Sensing in a Changing Climate and Environment: the Rift Valley Fever Case

    NASA Astrophysics Data System (ADS)

    Tourre, Y. M.; Lacaux, J.-P.; Vignolles, C.; Lafaye, M.

    2012-07-01

    Climate and environment are changing rapidly whilst global population already reached 7 billions people. New public health challenges are posed by new and re-emerging diseases. Innovation is a must i.e., 1) using high resolution remote sensing, 2) re-invent health politics and trans-disciplinary management. The above are part of the 'TransCube Approach' i.e., Transition, Translation, and Transformation. The new concept of Tele-epidemiology includes such approach. A conceptual approach (CA) associated with Rift Valley Fever (RVF) epidemics in Senegal is presented. Ponds are detected using high-resolution SPOT-5 satellite images and radar data from space. Data on rainfall events obtained from the Tropical Rainfall Measuring Mission (NASA/JAXA) are combined with in-situ data. Localization of vulnerable and parked hosts (obtained from QuickBird satellite) is also used. The dynamic spatio-temporal distribution and aggressiveness of RVF mosquitoes, are based on total rainfall amounts, ponds' dynamics and entomological observations. Detailed risks maps (hazards + vulnerability) in real-time are expressed in percentages of parks where animals are potentially at risks. This CA which simply relies upon rainfall distribution from space, is meant to contribute to the implementation of the RVF early warning system (RVFews). It is meant to be applied to other diseases and elsewhere. This is particularly true in new places where new vectors have been rapidly adapting (such as Aedes albopictus) whilst viruses (such as West Nile and Chikungunya,) circulate from constantly moving reservoirs and increasing population.

  17. International external quality assessment of molecular detection of Rift Valley fever virus.

    PubMed

    Escadafal, Camille; Paweska, Janusz T; Grobbelaar, Antoinette; le Roux, Chantel; Bouloy, Michèle; Patel, Pranav; Teichmann, Anette; Donoso-Mantke, Oliver; Niedrig, Matthias

    2013-01-01

    Rift Valley fever (RVF) is a viral zoonosis that primarily affects animals resulting in considerable economic losses due to death and abortions among infected livestock. RVF also affects humans with clinical symptoms ranging from an influenza-like illness to a hemorrhagic fever. Over the past years, RVF virus (RVFV) has caused severe outbreaks in livestock and humans throughout Africa and regions of the world previously regarded as free of the virus. This situation prompts the need to evaluate the diagnostic capacity and performance of laboratories worldwide. Diagnostic methods for RVFV detection include virus isolation, antigen and antibody detection methods, and nucleic acid amplification techniques. Molecular methods such as reverse-transcriptase polymerase chain reaction and other newly developed techniques allow for a rapid and accurate detection of RVFV. This study aims to assess the efficiency and accurateness of RVFV molecular diagnostic methods used by expert laboratories worldwide. Thirty expert laboratories from 16 countries received a panel of 14 samples which included RVFV preparations representing several genetic lineages, a specificity control and negative controls. In this study we present the results of the first international external quality assessment (EQA) for the molecular diagnosis of RVF. Optimal results were reported by 64% of the analyses, 21% of the analyses achieved acceptable results and 15% of the results revealed that there is need for improvement. Evenly good performances were achieved by specific protocols which can therefore be recommended as an accurate molecular protocol for the diagnosis of RVF. Other protocols showed uneven performances revealing the need for improved optimization and standardization of these protocols. PMID:23717706

  18. Modelling the effects of seasonality and socioeconomic impact on the transmission of rift valley Fever virus.

    PubMed

    Xiao, Yanyu; Beier, John C; Cantrell, Robert Stephen; Cosner, Chris; DeAngelis, Donald L; Ruan, Shigui

    2015-01-01

    Rift Valley fever (RVF) is an important mosquito-borne viral zoonosis in Africa and the Middle East that causes human deaths and significant economic losses due to huge incidences of death and abortion among infected livestock. Outbreaks of RVF are sporadic and associated with both seasonal and socioeconomic effects. Here we propose an almost periodic three-patch model to investigate the transmission dynamics of RVF virus (RVFV) among ruminants with spatial movements. Our findings indicate that, in Northeastern Africa, human activities, including those associated with the Eid al Adha feast, along with a combination of climatic factors such as rainfall level and hydrological variations, contribute to the transmission and dispersal of the disease pathogen. Moreover, sporadic outbreaks may occur when the two events occur together: 1) abundant livestock are recruited into areas at risk from RVF due to the demand for the religious festival and 2) abundant numbers of mosquitoes emerge. These two factors have been shown to have impacts on the severity of RVF outbreaks. Our numerical results present the transmission dynamics of the disease pathogen over both short and long periods of time, particularly during the festival time. Further, we investigate the impact on patterns of disease outbreaks in each patch brought by festival- and seasonal-driven factors, such as the number of livestock imported daily, the animal transportation speed from patch to patch, and the death rate induced by ceremonial sacrifices. In addition, our simulations show that when the time for festival preparation starts earlier than usual, the risk of massive disease outbreaks rises, particularly in patch 3 (the place where the religious ceremony will be held). PMID:25569474

  19. Characterizing the effect of Bortezomib on Rift Valley Fever Virus multiplication.

    PubMed

    Keck, Forrest; Amaya, Moushimi; Kehn-Hall, Kylene; Roberts, Brian; Bailey, Charles; Narayanan, Aarthi

    2015-08-01

    Rift Valley Fever Virus (RVFV) belongs to the family Bunyaviridae and is a known cause of epizootics and epidemics in Africa and the Middle East. With no FDA approved therapeutics available to treat RVFV infection, understanding the interactions between the virus and the infected host is crucial to developing novel therapeutic strategies. Here, we investigated the requirement of the ubiquitin-proteasome system (UPS) for the establishment of a productive RVFV infection. It was previously shown that the UPS plays a central role in RVFV multiplication involving degradation of PKR and p62 subunit of TFIIH. Using the FDA-approved proteasome inhibitor Bortezomib, we observed robust inhibition of intracellular and extracellular viral loads. Bortezomib treatment did not affect the nuclear/cytoplasmic distribution of the non-structural S-segment protein (NSs); however, the ability of NSs to form nuclear filaments was abolished as a result of Bortezomib treatment. In silico ubiquitination prediction analysis predicted that known NSs interactors (SAP30, YY1, and mSin3A) have multiple putative ubiquitination sites, while NSs itself was not predicted to be ubiquitinated. Immunoprecipitation studies indicated a decrease in interaction between SAP30 - NSs, and mSin3A - NSs in the context of Bortezomib treatment. This decrease in association between SAP30 - NSs also correlated with a decrease in the ubiquitination status of SAP30 with Bortezomib treatment. Bortezomib treatment, however, resulted in increased ubiquitination of mSin3A, suggesting that Bortezomib dynamically affects the ubiquitination status of host proteins that interact with NSs. Finally, we observed that expression of interferon beta (IFN-β) was increased in Bortezomib treated cells which indicated that the cellular antiviral mechanism was revived as a result of treatment and may contribute to control of viral multiplication. PMID:26001632

  20. Seroprevalence of Infections with Dengue, Rift Valley Fever and Chikungunya Viruses in Kenya, 2007

    PubMed Central

    Ochieng, Caroline; Ahenda, Petronella; Vittor, Amy Y.; Nyoka, Raymond; Gikunju, Stella; Wachira, Cyrus; Waiboci, Lilian; Umuro, Mamo; Kim, Andrea A.; Nderitu, Leonard; Juma, Bonventure; Montgomery, Joel M.; Breiman, Robert F.; Fields, Barry

    2015-01-01

    Arthropod-borne viruses are a major constituent of emerging infectious diseases worldwide, but limited data are available on the prevalence, distribution, and risk factors for transmission in Kenya and East Africa. In this study, we used 1,091 HIV-negative blood specimens from the 2007 Kenya AIDS Indicator Survey (KAIS 2007) to test for the presence of IgG antibodies to dengue virus (DENV), chikungunya virus (CHIKV) and Rift Valley fever virus (RVFV).The KAIS 2007 was a national population-based survey conducted by the Government of Kenya to provide comprehensive information needed to address the HIV/AIDS epidemic. Antibody testing for arboviruses was performed on stored blood specimens from KAIS 2007 through a two-step sandwich IgG ELISA using either commercially available kits or CDC-developed assays. Out of the 1,091 samples tested, 210 (19.2%) were positive for IgG antibodies against at least one of the three arboviruses. DENV was the most common of the three viruses tested (12.5% positive), followed by RVFV and CHIKV (4.5% and 0.97%, respectively). For DENV and RVFV, the participant’s province of residence was significantly associated (P≤.01) with seropositivity. Seroprevalence of DENV and RVFV increased with age, while there was no correlation between province of residence/age and seropositivity for CHIKV. Females had twelve times higher odds of exposure to CHIK as opposed to DENV and RVFV where both males and females had the same odds of exposure. Lack of education was significantly associated with a higher odds of previous infection with either DENV or RVFV (p <0.01). These data show that a number of people are at risk of arbovirus infections depending on their geographic location in Kenya and transmission of these pathogens is greater than previously appreciated. This poses a public health risk, especially for DENV. PMID:26177451

  1. Recent Outbreaks of Rift Valley Fever in East Africa and the Middle East

    PubMed Central

    Himeidan, Yousif E.; Kweka, Eliningaya J.; Mahgoub, Mostafa M.; El Rayah, El Amin; Ouma, Johnson O.

    2014-01-01

    Rift Valley fever (RVF) is an important neglected, emerging, mosquito-borne disease with severe negative impact on human and animal health. Mosquitoes in the Aedes genus have been considered as the reservoir, as well as vectors, since their transovarially infected eggs withstand desiccation and larvae hatch when in contact with water. However, different mosquito species serve as epizootic/epidemic vectors of RVF, creating a complex epidemiologic pattern in East Africa. The recent RVF outbreaks in Somalia (2006–2007), Kenya (2006–2007), Tanzania (2007), and Sudan (2007–2008) showed extension to districts, which were not involved before. These outbreaks also demonstrated the changing epidemiology of the disease from being originally associated with livestock, to a seemingly highly virulent form infecting humans and causing considerably high-fatality rates. The amount of rainfall is considered to be the main factor initiating RVF outbreaks. The interaction between rainfall and local environment, i.e., type of soil, livestock, and human determine the space-time clustering of RVF outbreaks. Contact with animals or their products was the most dominant risk factor to transfer the infection to humans. Uncontrolled movement of livestock during an outbreak is responsible for introducing RVF to new areas. For example, the virus that caused the Saudi Arabia outbreak in 2000 was found to be the same strain that caused the 1997–98 outbreaks in East Africa. A strategy that involves active surveillance with effective case management and diagnosis for humans and identifying target areas for animal vaccination, restriction on animal movements outside the affected areas, identifying breeding sites, and targeted intensive mosquito control programs has been shown to succeed in limiting the effect of RVF outbreak and curb the spread of the disease from the onset. PMID:25340047

  2. Modelling the Effects of Seasonality and Socioeconomic Impact on the Transmission of Rift Valley Fever Virus

    PubMed Central

    Xiao, Yanyu; Beier, John C.; Cantrell, Robert Stephen; Cosner, Chris; DeAngelis, Donald L.; Ruan, Shigui

    2015-01-01

    Rift Valley fever (RVF) is an important mosquito-borne viral zoonosis in Africa and the Middle East that causes human deaths and significant economic losses due to huge incidences of death and abortion among infected livestock. Outbreaks of RVF are sporadic and associated with both seasonal and socioeconomic effects. Here we propose an almost periodic three-patch model to investigate the transmission dynamics of RVF virus (RVFV) among ruminants with spatial movements. Our findings indicate that, in Northeastern Africa, human activities, including those associated with the Eid al Adha feast, along with a combination of climatic factors such as rainfall level and hydrological variations, contribute to the transmission and dispersal of the disease pathogen. Moreover, sporadic outbreaks may occur when the two events occur together: 1) abundant livestock are recruited into areas at risk from RVF due to the demand for the religious festival and 2) abundant numbers of mosquitoes emerge. These two factors have been shown to have impacts on the severity of RVF outbreaks. Our numerical results present the transmission dynamics of the disease pathogen over both short and long periods of time, particularly during the festival time. Further, we investigate the impact on patterns of disease outbreaks in each patch brought by festival- and seasonal-driven factors, such as the number of livestock imported daily, the animal transportation speed from patch to patch, and the death rate induced by ceremonial sacrifices. In addition, our simulations show that when the time for festival preparation starts earlier than usual, the risk of massive disease outbreaks rises, particularly in patch 3 (the place where the religious ceremony will be held). PMID:25569474

  3. Land-use and land-cover dynamics in the central rift valley of Ethiopia.

    PubMed

    Garedew, Efrem; Sandewall, Mats; Söderberg, Ulf; Campbell, Bruce M

    2009-10-01

    Understanding the complexity of land-use and land-cover (LULC) changes and their driving forces and impacts on human and environmental security is important for the planning of natural resource management and associated decision making. This study combines and compares participatory field point sampling (pfps) and remote sensing to explore local LULC dynamics. The study was conducted in two peasant associations located in the central Ethiopian Rift Valley, which is a dry-land mixed farming area exposed to rapid deforestation. From 1973-2006, the area of cropland doubled at the expense of woodland and wooded-grassland in both of the study sites. Major deforestation and forest degradation took place from 1973-1986; woodland cover declined from 40% to 9% in one of the study sites, while the other lost all of its original 54% woodland cover. Our study concludes that assessing LULC dynamics using a combination of remote sensing and pfps is a valuable approach. The two methods revealed similar LULC trends, while the pfps provided additional details on how farmers view the changes. This study documents dramatic trends in LULC over time, associated with rapid population growth, recurrent drought, rainfall variability and declining crop productivity. The alarming nature of these trends is reflected in a decrease in the livelihood security of local communities and in environmental degradation. Given these dry-land conditions, there are few opportunities to improve livelihoods and environmental security without external support. If negative changes are to be halted, action must be taken, including building asset bases, instituting family planning services, and creating opportunities outside these marginal environments. PMID:19688359

  4. Immunogenicity and efficacy of a chimpanzee adenovirus-vectored Rift Valley Fever vaccine in mice

    PubMed Central

    2013-01-01

    Background Rift Valley Fever (RVF) is a viral zoonosis that historically affects livestock production and human health in sub-Saharan Africa, though epizootics have also occurred in the Arabian Peninsula. Whilst an effective live-attenuated vaccine is available for livestock, there is currently no licensed human RVF vaccine. Replication-deficient chimpanzee adenovirus (ChAd) vectors are an ideal platform for development of a human RVF vaccine, given the low prevalence of neutralizing antibodies against them in the human population, and their excellent safety and immunogenicity profile in human clinical trials of vaccines against a wide range of pathogens. Methods Here, in BALB/c mice, we evaluated the immunogenicity and efficacy of a replication-deficient chimpanzee adenovirus vector, ChAdOx1, encoding the RVF virus envelope glycoproteins, Gn and Gc, which are targets of virus neutralizing antibodies. The ChAdOx1-GnGc vaccine was assessed in comparison to a replication-deficient human adenovirus type 5 vector encoding Gn and Gc (HAdV5-GnGc), a strategy previously shown to confer protective immunity against RVF in mice. Results A single immunization with either of the vaccines conferred protection against RVF virus challenge eight weeks post-immunization. Both vaccines elicited RVF virus neutralizing antibody and a robust CD8+ T cell response. Conclusions Together the results support further development of RVF vaccines based on replication-deficient adenovirus vectors, with ChAdOx1-GnGc being a potential candidate for use in future human clinical trials. PMID:24304565

  5. A Glycoprotein Subunit Vaccine Elicits a Strong Rift Valley Fever Virus Neutralizing Antibody Response in Sheep

    PubMed Central

    Lebedev, Maxim; McVey, D. Scott; Wilson, William; Morozov, Igor; Young, Alan

    2014-01-01

    Abstract Rift Valley fever virus (RVFV), a member of the Bunyaviridae family, is a mosquito-borne zoonotic pathogen that causes serious morbidity and mortality in livestock and humans. The recent spread of the virus beyond its traditional endemic boundaries in Africa to the Arabian Peninsula coupled with the presence of susceptible vectors in nonendemic countries has created increased interest in RVF vaccines. Subunit vaccines composed of specific virus proteins expressed in eukaryotic or prokaryotic expression systems are shown to elicit neutralizing antibodies in susceptible hosts. RVFV structural proteins, amino-terminus glycoprotein (Gn), and carboxyl-terminus glycoprotein (Gc), were expressed using a recombinant baculovirus expression system. The recombinant proteins were reconstituted as a GnGc subunit vaccine formulation and evaluated for immunogenicity in a target species, sheep. Six sheep were each immunized with a primary dose of 50 μg of each vaccine immunogen with the adjuvant montanide ISA25; at day 21, postvaccination, each animal received a second dose of the same vaccine. The vaccine induced a strong antibody response in all animals as determined by indirect enzyme-linked immunosorbent assay (ELISA). A plaque reduction neutralization test (PRNT80) showed the primary dose of the vaccine was sufficient to elicit potentially protective virus neutralizing antibody titers ranging from 40 to 160, and the second vaccine dose boosted the titer to more than 1280. Furthermore, all animals tested positive for neutralizing antibodies at day 328 postvaccination. ELISA analysis using the recombinant nucleocapsid protein as a negative marker antigen indicated that the vaccine candidate is DIVA (differentiating infected from vaccinated animals) compatible and represents a promising vaccine platform for RVFV infection in susceptible species. PMID:25325319

  6. Evidence for Circulation of the Rift Valley Fever Virus among Livestock in the Union of Comoros

    PubMed Central

    Soulé, Miradje; Faharoudine, Abdourahime; Foray, Coralie; Olive, Marie-Marie; Maquart, Marianne; Soulaimane, Abdouroihamane; Madi Kassim, Ahmed; Cêtre-Sossah, Catherine; Cardinale, Eric

    2014-01-01

    Rift Valley fever virus (RVFV) is an arthropod-borne phlebovirus reported to be circulating in most parts of Africa. Since 2009, RVFV has been suspected of continuously circulating in the Union of Comoros. To estimate the incidence of RVFV antibody acquisition in the Comorian ruminant population, 191 young goats and cattle were selected in six distinct zones and sampled periodically from April 2010 to August 2011. We found an estimated incidence of RVFV antibody acquisition of 17.5% (95% confidence interval (CI): [8.9–26.1]) with a significant difference between islands (8.2% in Grande Comore, 72.3% in Moheli and 5.8% in Anjouan). Simultaneously, a longitudinal entomological survey was conducted and ruminant trade-related information was collected. No RVFV RNA was detected out of the 1,568 blood-sucking caught insects, including three potential vectors of RVFV mosquito species. Our trade survey suggests that there is a continuous flow of live animals from eastern Africa to the Union of Comoros and movements of ruminants between the three Comoro islands. Finally, a cross-sectional study was performed in August 2011 at the end of the follow-up. We found an estimated RVFV antibody prevalence of 19.3% (95% CI: [15.6%–23.0%]). Our findings suggest a complex RVFV epidemiological cycle in the Union of Comoros with probable inter-islands differences in RVFV circulation patterns. Moheli, and potentially Anjouan, appear to be acting as endemic reservoir of infection whereas RVFV persistence in Grande Comore could be correlated with trade in live animals with the eastern coast of Africa. More data are needed to estimate the real impact of the disease on human health and on the national economy. PMID:25078616

  7. Structure of the Rift Valley fever virus nucleocapsid protein reveals another architecture for RNA encapsidation

    SciTech Connect

    Raymond, Donald D.; Piper, Mary E.; Gerrard, Sonja R.; Smith, Janet L.

    2010-07-13

    Rift Valley fever virus (RVFV) is a negative-sense RNA virus (genus Phlebovirus, family Bunyaviridae) that infects livestock and humans and is endemic to sub-Saharan Africa. Like all negative-sense viruses, the segmented RNA genome of RVFV is encapsidated by a nucleocapsid protein (N). The 1.93-{angstrom} crystal structure of RVFV N and electron micrographs of ribonucleoprotein (RNP) reveal an encapsidated genome of substantially different organization than in other negative-sense RNA virus families. The RNP polymer, viewed in electron micrographs of both virus RNP and RNP reconstituted from purified N with a defined RNA, has an extended structure without helical symmetry. N-RNA species of {approx}100-kDa apparent molecular weight and heterogeneous composition were obtained by exhaustive ribonuclease treatment of virus RNP, by recombinant expression of N, and by reconstitution from purified N and an RNA oligomer. RNA-free N, obtained by denaturation and refolding, has a novel all-helical fold that is compact and well ordered at both the N and C termini. Unlike N of other negative-sense RNA viruses, RVFV N has no positively charged surface cleft for RNA binding and no protruding termini or loops to stabilize a defined N-RNA oligomer or RNP helix. A potential protein interaction site was identified in a conserved hydrophobic pocket. The nonhelical appearance of phlebovirus RNP, the heterogeneous {approx}100-kDa N-RNA multimer, and the N fold differ substantially from the RNP and N of other negative-sense RNA virus families and provide valuable insights into the structure of the encapsidated phlebovirus genome.

  8. Natural resources and their prospects in the closed basins of rift valley marginal grabens in northern Ethiopia

    NASA Astrophysics Data System (ADS)

    Meaza, Hailemariam; Frankl, Amaury; Poesen, Jean; Zenebe, Amanuel; Deckers, Jozef; Vaneetvelde, Veerle; Lanckriet, Sil; Nyssen, Jan

    2016-04-01

    With increasing population, producing more food and fibers has led to an expansion of the area under cultivation. For this, much attention is given to low-lying flat areas in search of suitable agricultural lands. The objectives of this paper are therefore: (1) to review the opportunities and challenges of natural resources in the marginal grabens for rural development; (2) to highlight the knowledge gaps and priorities in research and development in the marginal grabens, and (3) to supplement the literature review through repeat transect walks, focus group discussions and interviews across the western rift valley of northern Ethiopia. The paper shows that marginal grabens along the rift valleys are rich both in blue and green water resources due to their topographical and geological characteristics. Spate irrigation has been a growing water management practice to respond to soil moisture deficit. Besides, marginal grabens are fertile plains as a result of alluvial deposition that could be suitable for agricultural development. However, rainfall variability and groundwater withdrawal lead to graben basin closure and salinization. Notably, riverbed incisions and sediment deposition affects drainage systems and water supply in the marginal grabens. As a result, socioeconomic and natural capital of the marginal graben farmers are continuously threatened. Thus, the benefits of natural resources for rural development in the marginal grabens along the rift valley can be optimized if the current bottlenecks are converted into opportunities. A better understanding of the complex marginal graben system via a robust land evaluation framework will improve livelihoods of the communities that live in the (closed) marginal grabens. Keywords: population pressure, marginal grabens, endorheic lakes, salinization, Ethiopia

  9. Evidence for hot Mississippi Valley-type brines in the Reelfoot Rift complex, south-central United States, in Late Pennsylvanian-Early Permian

    USGS Publications Warehouse

    Leach, D.L.; Apodaca, L.E.; Repetski, J.E.; Powell, J.W.; Rowan, E.L.

    1997-01-01

    Petrographic and fluid inclusion studies of sparry dolomite cement from Upper Cambrian to Lower Ordovician rocks and conodont thermal-alteration indices provide evidence that hot mississippi valley-type brines were once present in the Reelfoot Rift complex. The cathodoluminescent microstratigraphy of sparry dolomite cement in the Reelfoot Rift resembles that of sparry dolomite cement associated with widespread mississippi valley-type deposition in the Ozark region. If correlative cathodoluminescent zones in the sparry dolomite from the Ozark and Reelfoot Rift regions indicate broadly contemporaneous dolomite deposition, then the results show that the Ozark MVT-type hydrothermal system extended into the Reelfoot region and onto the western flank of the Nashville Dome. Independent evidence supports migration of MVT-type brines into the Ozark region from the Reelfoot Rift complex in late Paleozoic time.

  10. Structural controls on the spatial distribution and geochemical composition of volcanism in a continental rift zone; an example from Owens Valley, eastern California

    NASA Astrophysics Data System (ADS)

    Haproff, P. J.; Yin, A.

    2014-12-01

    Bimodal volcanism is common in continental rift zones. Structural controls to the emplacement and compositions of magmas, however, are not well understood. To address this issue, we examine the location, age, and geochemistry of active volcanic centers, and geometry and kinematics of rift-related faults across the active transtensional Owens Valley rift zone. Building on existing studies, we postulate that the spatial distribution and geochemical composition of volcanism are controlled by motion along rift-bounding fault systems. Along-strike variation in fault geometry and characteristics of active volcanism allow us to divide Owens Valley into three segments: southern, northern, and central. The southern segment of Owens Valley is a simple shear, asymmetric rift bounded to the west by the east-dipping Sierra Nevada frontal fault (SNFF). Active vents of Coso volcanic field are distributed along the eastern rift shoulder and characterized by the eruption of bimodal lavas. The SNFF within this segment is low-angle and penetrates through the lithosphere and into the ductile asthenosphere, allowing for mantle-derived magma to migrate across the weakest part of the fault zone beneath the eastern rift shoulder. Magma thermally weakens wall rocks and eventually stalls in the crust where the melt develops a greater felsic component prior to eruption. The northern segment of Owens Valley displays similar structural geometry, as the west-dipping White Mountains fault (WMF) is listric at depth and offsets the crust and mantle lithosphere, allowing for vertical transport of magma and reservoir emplacement within the crust. Bimodal lavas periodically erupted in the Long Valley Caldera region along the western rift shoulder. The central segment of Owens Valley is a pure shear, symmetric graben generated by motion along the SNFF and WMF. The subvertical, right-slip Owens Valley fault (OVF) strikes along the axis of the valley and penetrates through the lithosphere into the

  11. Rift Valley fever virus (family Bunyaviridae, genus Phlebovirus). Isolations from Diptera collected during an inter-epizootic period in Kenya.

    PubMed Central

    Linthicum, K. J.; Davies, F. G.; Kairo, A.; Bailey, C. L.

    1985-01-01

    A total of 134 876 Diptera collected in Kenya during a 3-year period were tested in 3383 pools for Rift Valley fever (RVF) virus. Nineteen pools of unengorged mosquitoes were found positive for RVF. All isolations were made from specimens collected at or near the naturally or artificially flooded grassland depressions that serve as the developmental sites for the immature stages of many mosquito species. The isolation of virus from adult male and female A. lineatopennis which had been reared from field-collected larvae and pupae suggests that transovarial transmission of the virus occurs in this species. PMID:2862206

  12. Reverse genetics technology for Rift Valley fever virus: current and future applications for the development of therapeutics and vaccines.

    PubMed

    Bouloy, Michele; Flick, Ramon

    2009-11-01

    The advent of reverse genetics technology has revolutionized the study of RNA viruses, making it possible to manipulate their genomes and evaluate the effects of these changes on their biology and pathogenesis. The fundamental insights gleaned from reverse genetics-based studies over the last several years provide a new momentum for the development of designed therapies for the control and prevention of these viral pathogens. This review summarizes the successes and stumbling blocks in the development of reverse genetics technologies for Rift Valley fever virus and their application to the further dissection of its pathogenesis and the design of new therapeutics and safe and effective vaccines. PMID:19682499

  13. Mixing models and ionic geothermometers applied to warm (up to 60°C) springs: Jordan Rift Valley, Israel

    USGS Publications Warehouse

    Mazor, E.; Levitte, D.; Truesdell, A.H.; Healy, J.; Nissenbaum, A.

    1980-01-01

    No indications are available for the existence of above-boiling geothermal systems in the Jordan Rift Valley. Slightly higher than observed temperatures are concluded for a deep component at the springs of Hammat Gader (67°C), Gofra (68°C), the Russian Garden (40°C), and the Yesha well (53–65°C). These temperatures may encourage further developments for spas and bathing installations and, to a limited extent, for space heating, but are not favorable for geothermal power generation.

  14. Integrated Analysis of Environment, Cattle and Human Serological Data: Risks and Mechanisms of Transmission of Rift Valley Fever in Madagascar

    PubMed Central

    Olive, Marie-Marie; Chevalier, Véronique; Grosbois, Vladimir; Tran, Annelise; Andriamandimby, Soa-Fy; Durand, Benoit; Ravalohery, Jean-Pierre; Andriamamonjy, Seta; Rakotomanana, Fanjasoa; Rogier, Christophe; Heraud, Jean-Michel

    2016-01-01

    Background Rift Valley fever (RVF) is a vector-borne disease affecting ruminants and humans. Madagascar was heavily affected by RVF in 2008–2009, with evidence of a large and heterogeneous spread of the disease. The identification of at-risk environments is essential to optimize the available resources by targeting RVF surveillance in Madagascar. Herein, the objectives of our study were: (i) to identify the environmental factors and areas favorable to RVF transmission to both cattle and human and (ii) to identify human behaviors favoring human infections in Malagasy contexts. Methodology/Principal Findings First, we characterized the environments of Malagasy communes using a Multiple Factor Analysis (MFA). Then, we analyzed cattle and human serological data collected at national level using Generalized Linear Mixed Models, with the individual serological status (cattle or human) as the response, and MFA factors, as well as other potential risk factors (cattle density, human behavior) as explanatory variables. Cattle and human seroprevalence rates were positively associated to humid environments (p<0.001). Areas with high cattle density were at risk (p<0.01; OR = 2.6). Furthermore, our analysis showed that frequent contact with raw milk contributed to explain human infection (OR = 1.6). Finally, our study highlighted the eastern-coast, western and north-western parts as high-risk areas for RVF transmission in cattle. Conclusions/Significance Our integrated approach analyzing environmental, cattle and human datasets allow us to bring new insight on RVF transmission patterns in Madagascar. The association between cattle seroprevalence, humid environments and high cattle density suggests that concomitant vectorial and direct transmissions are critical to maintain RVF enzootic transmission. Additionally, in the at-risk humid environment of the western, north-western and the eastern-coast areas, suitable to Culex and Anopheles mosquitoes, vectorial transmission

  15. First External Quality Assessment of Molecular and Serological Detection of Rift Valley Fever in the Western Mediterranean Region

    PubMed Central

    Monaco, Federica; Cosseddu, Gian Mario; Doumbia, Baba; Madani, Hafsa; El Mellouli, Fatiha; Jiménez-Clavero, Miguel Angel; Sghaier, Soufien; Marianneau, Philippe; Cetre-Sossah, Catherine; Polci, Andrea; Lacote, Sandra; Lakhdar, Magtouf; Fernandez-Pinero, Jovita; Sari Nassim, Chabane; Pinoni, Chiara; Capobianco Dondona, Andrea; Gallardo, Carmina; Bouzid, Taoufiq; Conte, Annamaria; Bortone, Grazia; Savini, Giovanni; Petrini, Antonio; Puech, Lilian

    2015-01-01

    Rift Valley fever (RVF) is a mosquito-borne viral zoonosis which affects humans and a wide range of domestic and wild ruminants. The large spread of RVF in Africa and its potential to emerge beyond its geographic range requires the development of surveillance strategies to promptly detect the disease outbreaks in order to implement efficient control measures, which could prevent the widespread of the virus to humans. The Animal Health Mediterranean Network (REMESA) linking some Northern African countries as Algeria, Egypt, Libya, Mauritania, Morocco, Tunisia with Southern European ones as France, Italy, Portugal and Spain aims at improving the animal health in the Western Mediterranean Region since 2009. In this context, a first assessment of the diagnostic capacities of the laboratories involved in the RVF surveillance was performed. The first proficiency testing (external quality assessment—EQA) for the detection of the viral genome and antibodies of RVF virus (RVFV) was carried out from October 2013 to February 2014. Ten laboratories participated from 6 different countries (4 from North Africa and 2 from Europe). Six laboratories participated in the ring trial for both viral RNA and antibodies detection methods, while four laboratories participated exclusively in the antibodies detection ring trial. For the EQA targeting the viral RNA detection methods 5 out of 6 laboratories reported 100% of correct results. One laboratory misidentified 2 positive samples as negative and 3 positive samples as doubtful indicating a need for corrective actions. For the EQA targeting IgG and IgM antibodies methods 9 out of the 10 laboratories reported 100% of correct results, whilst one laboratory reported all correct results except one false-positive. These two ring trials provide evidence that most of the participating laboratories are capable to detect RVF antibodies and viral RNA thus recognizing RVF infection in affected ruminants with the diagnostic methods currently

  16. The Environmental Settings of Homo-Sapience Dispersal and the Neolithic Revolution in the Dead Sea - Red Sea Rift Valley

    NASA Astrophysics Data System (ADS)

    Stein, M.

    2014-12-01

    The Dead Sea-Red Sea Rift accommodated climatic and historic events that have fundamentally influenced the evolution of hominids. Among these developments, the Homo-Sapience (HS) dispersal "out of Africa" and the "Neolithic Revolution (NR)" represent major benchmarks. These developments occurred during the last interglacial and the post-glacial periods when the Red Sea - Levant region was overall arid. Nevertheless, wetter intervals prevailed within these arid periods, allowed the human culture development. The information on these wetter periods is stored in the sedimentary archives that were formed in the Rift. Lake Lisan that expanded all over the Dead Sea- Jordan- Kinnarot basin during the last glacial period retreated and contracted when the ice receded at the northern latitudes. At ~ 14-13 ka BP the lake dropped abruptly and deposited thick sequences of halite. Subsequently, terra rossa soil was re-mobilized from the Judea Mountains and accumulated along the Jordan Valley comprising the Fazael Fm. This soil and the availability of water in the Jordan Valley allow the establishment of the early agriculture settlements of Jericho, Gilgal and Fazael (at ~10-9 ka BP, the "peak" of sapropel S1, when enhance flow of Nile waters arrived to the Mediterranean). During the last interglacial HS dispersal occurs along the Red Sea- Jordan Valley corridor. Evidence for periods of wetness in this rather hyperarid region comes from fringing coral reefs along the Red Sea- Gulf of Aqaba shores, speleothems and travertines in the southern Negev desert -Arava valley and from lake sediments that were recently drilled at the deepest floor of the Dead Sea. All inventories indicate interval of enhanced wetness at ~ 128-122 ka BP, when sapropel S5 occurred. Thus, it appears that the periods of sapropels S1 and S5 were favorite for human culture development along the Red Sea - Jordan rift valley. Nevertheless, these human-development periods terminated abruptly at ~118-116 ka BP and

  17. Factors Associated with Severe Human Rift Valley Fever in Sangailu, Garissa County, Kenya

    PubMed Central

    LaBeaud, A. Desirée; Pfeil, Sarah; Muiruri, Samuel; Dahir, Saidi; Sutherland, Laura J.; Traylor, Zachary; Gildengorin, Ginny; Muchiri, Eric M.; Morrill, John; Peters, C. J.; Hise, Amy G.; Kazura, James W; King, Charles H.

    2015-01-01

    Background Mosquito-borne Rift Valley fever virus (RVFV) causes acute, often severe, disease in livestock and humans. To determine the exposure factors and range of symptoms associated with human RVF, we performed a population-based cross-sectional survey in six villages across a 40 km transect in northeastern Kenya. Methodology/Principal Findings: A systematic survey of the total populations of six Northeastern Kenyan villages was performed. Among 1082 residents tested via anti-RVFV IgG ELISA, seroprevalence was 15% (CI95%, 13–17%). Prevalence did not vary significantly among villages. Subject age was a significant factor, with 31% (154/498) of adults seropositive vs. only 2% of children ≤15 years (12/583). Seroprevalence was higher among men (18%) than women (13%). Factors associated with seropositivity included a history of animal exposure, non-focal fever symptoms, symptoms related to meningoencephalitis, and eye symptoms. Using cluster analysis in RVFV positive participants, a more severe symptom phenotype was empirically defined as having somatic symptoms of acute fever plus eye symptoms, and possibly one or more meningoencephalitic or hemorrhagic symptoms. Associated with this more severe disease phenotype were older age, village, recent illness, and loss of a family member during the last outbreak. In multivariate analysis, sheltering livestock (aOR = 3.5 CI95% 0.93–13.61, P = 0.065), disposing of livestock abortus (aOR = 4.11, CI95% 0.63–26.79, P = 0.14), and village location (P = 0.009) were independently associated with the severe disease phenotype. Conclusions/Significance Our results demonstrate that a significant proportion of the population in northeastern Kenya has been infected with RVFV. Village and certain animal husbandry activities were associated with more severe disease. Older age, male gender, herder occupation, killing and butchering livestock, and poor visual acuity were useful markers for increased RVFV infection. Formal vision

  18. Sheep Skin Odor Improves Trap Captures of Mosquito Vectors of Rift Valley Fever

    PubMed Central

    Tchouassi, David P.; Sang, Rosemary; Sole, Catherine L.; Bastos, Armanda D. S.; Mithoefer, Klaus; Torto, Baldwyn

    2012-01-01

    In recent years, the East African region has seen an increase in arboviral diseases transmitted by blood-feeding arthropods. Effective surveillance to monitor and reduce incidence of these infections requires the use of appropriate vector sampling tools. Here, trapped skin volatiles on fur from sheep, a known preferred host of mosquito vectors of Rift Valley fever virus (RVFV), were used with a standard CDC light trap to improve catches of mosquito vectors. We tested the standard CDC light trap alone (L), and baited with (a) CO2 (LC), (b) animal volatiles (LF), and (c) CO2 plus animal volatiles (LCF) in two highly endemic areas for RVF in Kenya (Marigat and Ijara districts) from March–June and September–December 2010. The incidence rate ratios (IRR) that mosquito species chose traps baited with treatments (LCF, LC and LF) instead of the control (L) were estimated. Marigat was dominated by secondary vectors and host-seeking mosquitoes were 3–4 times more likely to enter LC and LCF traps [IRR = 3.1 and IRR = 3.8 respectively] than the L only trap. The LCF trap captured a greater number of mosquitoes than the LC trap (IRR = 1.23) although the difference was not significant. Analogous results were observed at Ijara, where species were dominated by key primary and primary RVFV vectors, with 1.6-, 6.5-, and 8.5-fold increases in trap captures recorded in LF, LC and LCF baited traps respectively, relative to the control. These catches all differed significantly from those trapped in L only. Further, there was a significant increase in trap captures in LCF compared to LC (IRR = 1.63). Mosquito species composition and trap counts differed between the RVF sites. However, within each site, catches differed in abundance only and no species preferences were noted in the different baited-traps. Identifying the attractive components present in these natural odors should lead to development of an effective odor-bait trapping system for population density

  19. Trace element mobility and transfer to vegetation within the Ethiopian Rift Valley lake areas.

    PubMed

    Kassaye, Yetneberk A; Skipperud, Lindis; Meland, Sondre; Dadebo, Elias; Einset, John; Salbu, Brit

    2012-10-26

    To evaluate critical trace element loads in native vegetation and calculate soil-to-plant transfer factors (TFs), 11 trace elements (Cr, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Pb and Mn) have been determined in leaves of 9 taxonomically verified naturally growing terrestrial plant species as well as in soil samples collected around 3 Ethiopian Rift Valley lakes (Koka, Ziway and Awassa). The Cr concentration in leaves of all the plant species was higher than the "normal" range, with the highest level (8.4 mg per kg dw) being observed in Acacia tortilis from the Lake Koka area. Caper species (Capparis fascicularis) and Ethiopian dogstooth grass (Cynodon aethiopicus) from Koka also contained exceptionally high levels of Cd (1 mg per kg dw) and Mo (32.8 mg per kg dw), respectively. Pb, As and Cu concentrations were low in the plant leaves from all sites. The low Cu level in important fodder plant species (Cynodon aethiopicus, Acacia tortilis and Opuntia ficus-indicus) implies potential deficiency in grazing and browsing animals. Compared to the Canadian environmental quality guideline and maximum allowable concentration in agricultural soils, the total soil trace element concentrations at the studied sites are safe for agricultural crop production. Enrichment factor was high for Zn in soils around Lakes Ziway and Awassa, resulting in moderate to high transfer of Zn to the studied plants. A six step sequential extraction procedure on the soils revealed a relatively high mobility of Cd, Se and Mn. Strong association of most trace elements with the redox sensitive fraction and mineral lattice was also confirmed by partial redundancy analysis. TF (mg per kg dw plants/mg per kg dw soil) values based on the total (TF(total)) and mobile fractions (TF(mobile)) of soil trace element concentrations varied widely among elements and plant species, with the averaged TF(total) and TF(mobile) values ranging from 0.01-2 and 1-60, respectively. Considering the mobile fraction in soils should

  20. Occurrence of rift valley fever in cattle in Ijara district, Kenya.

    PubMed

    Owange, Nelson O; Ogara, William O; Affognon, Hippolyte; Peter, Gathura B; Kasiiti, Jacqueline; Okuthe, Sam; Onyango-Ouma, W; Landmann, Tobias; Sang, Rosemary; Mbabu, Murithi

    2014-11-01

    Ijara district in Kenya was one of the hotspots of rift valley fever (RVF) during the 2006/2007 outbreak which led to human and animal deaths causing huge economic and public health losses. The main constraint in the control and prevention of RVF is inadequate knowledge on its occurrence during the interepidemic period. This study was aimed at understanding the occurrence of RVF in cattle in Ijara to enable the development of improved community-based disease surveillance, prediction, control and prevention. Six herds each 700-1000 cattle were identified with participatory involvement of locals and project technical team of the project. One animal per herd was tagged with global position system (GPS) collar to enable follow up. Sero-surveys were conducted periodically to understand the herd's movement through various ecological zones and risk of exposure to RVF virus. Sixty animals less than 3 years old from each herd were randomly selected each sampling time and sero-surveyed for RVF four times (September 2012, December 2012, February 2013 and May 2013) during the study period and along the nomadic movement route. The serum samples collected were subjected to RVF inhibition ELISA test to detect if there was exposure for RVF virus (RVFV). The RVF inhibition ELISA positive samples were subjected to IgM ELISA test to determine if the exposures were current or recent (within 14 days). The result of the survey indicated that 13.1% (183/1396) of cattle sero-surveyed had RVFV antibodies by inhibition ELISA test while 1.4% (18/1396) was positive for IgM ELISA test. The highest RVFV circulation was detected after herds pass through bony forest between Lamu and Ijara and Halei forested areas. These forested areas also had the highest IgM detections. The findings indicate that even limited rainfall was able to initiate RVFV circulation in Ijara region with highest circulation detected within forested areas with potential to become epidemic if rains persist with extensive

  1. Imaging the midcontinent rift beneath Lake Superior using large aperture seismic data

    USGS Publications Warehouse

    Trehu, Anne M.; Morel-a-l'Huissier, Patrick; Meyer, R.; Hajnal, Z.; Karl, J.; Mereu, R. F.; Sexton, J.; Shay, J.; Chan, W. K.; Epili, D.; Jefferson, T.; Shih, X. R.; Wendling, S.; Milkereit, B.; Green, A.; Hutchinson, Deborah R.

    1991-01-01

    We present a detailed velocity model across the 1.1 billion year old Midcontinent Rift System (MRS) in central Lake Superior. The model was derived primarily from onshore-offshore large-aperture seismic and gravity data. High velocities obtained within a highly reflective half-graben that was imaged on coincident seismic reflection data demonstrate the dominantly mafic composition of the graben fill and constrain its total thickness to be at least 30km. Strong wide-angle reflections are observed from the lower crust and Moho, indicating that the crust is thickest (55–60km) beneath the axis of the graben. The total crustal thickness decreases rapidly to about 40 km beneath the south shore of the lake and decreases more gradually to the north. Above the Moho is a high-velocity lower crust interpreted to result from syn-rift basaltic intrusion into and/or underplating beneath the Archean lower crust. The lower crust is thickest beneath the axis of the main rift half-graben. A second region of thick lower crust is found approximately 100km north of the axis of the rift beneath a smaller half graben that is interpreted to reflect an earlier stage of rifting. The crustal model presented here resembles recent models of some passive continental margins and is in marked contrast to many models of both active and extinct Phanerozoic continental rift zones. It demonstrates that the Moho is a dynamic feature, since the pre-rift Moho is probably within or above the high-velocity lower crust, whereas the post-rift Moho is defined as the base of this layer. In the absence of major tectonic activity, however, the Moho is very stable, since the large, abrupt variations in crustal thickness beneath the MRS have been preserved for at least a billion years.

  2. Two diamictites, two cap carbonates, two δ13C excursions, two rifts: The Neoproterozoic Kingston Peak Formation, Death Valley, California

    NASA Astrophysics Data System (ADS)

    Prave, A. R.

    1999-04-01

    Stratigraphic mapping of the Neoproterozoic glaciogenic Kingston Peak Formation (Death Valley, California) provides evidence for two temporally discrete extensional deformation episodes. These episodes are bracketed by the Sourdough Limestone and Noonday Dolomite, the facies characteristics and δ13C data (ranging between 2.15 and -2.56‰ and -1.88 and -4.86‰, respectively) of which make them equivalent to Sturtian and Varangian age cap carbonates, respectively. This constrains the two extensional episodes along the southwestern margin of Laurentia to ca. 700 Ma and ca. 600 Ma. These observations and data show that the field evidence for mid-Neoproterozoic breakup and the predictions from tectonic subsidence curves for a latest Neoproterozoic breakup are both correct. Thus, Neoproterozoic plate reconstructions must account for two discrete rift episodes separated by 100 m.y. or more. Confining rifting to within the Kingston Peak Formation thereby places the younger Proterozoic rocks of the southwestern Great Basin in the rift to drift tectonic phase.

  3. Temperature-sensitive mutations for live-attenuated Rift Valley fever vaccines: implications from other RNA viruses

    PubMed Central

    Nishiyama, Shoko; Ikegami, Tetsuro

    2015-01-01

    Rift Valley fever (RVF) is a mosquito-borne zoonotic disease endemic to the African continent. RVF is characterized by high rate of abortions in ruminants and hemorrhagic fever, encephalitis, or blindness in humans. RVF is caused by the Rift Valley fever virus (RVFV: genus Phlebovirus, family Bunyaviridae). Vaccination is the only known effective strategy to prevent the disease, but there are no licensed RVF vaccines available for humans. A live-attenuated vaccine candidate derived from the wild-type pathogenic Egyptian ZH548 strain, MP-12, has been conditionally licensed for veterinary use in the U.S. MP-12 displays a temperature-sensitive (ts) phenotype and does not replicate at 41°C. The ts mutation limits viral replication at a specific body temperature and may lead to an attenuation of the virus. Here we will review well-characterized ts mutations for RNA viruses, and further discuss the potential in designing novel live-attenuated vaccines for RVF. PMID:26322023

  4. Mixing models and ionic geothermometers applied to warm (up to 60°C) springs: Jordan Rift Valley, Israel

    NASA Astrophysics Data System (ADS)

    Mazor, E.; Levitte, D.; Truesdell, A. H.; Healy, J.; Nissenbaum, A.

    1980-01-01

    Mixing models and evaluation of SiO 2 contents of warm-water manifestations in the Jordan—Dead Sea Rift Valley indicate that these waters are fed by aquifers with estimated temperatures of up to 68°C. These calculations and Na/K ratios, concentrations of Na, K and Ca, concentrations of atmospheric Ne, Ar, Kr and Xe; and concentrations of the stable hydrogen and oxygen isotopes all indicate below-boiling temperatures. No indications are available for the existence of above-boiling geothermal systems in the Jordan Rift Valley. Slightly higher than observed temperatures are concluded for a deep component at the springs of Hammat Gader (67°C), Gofra (68°C), the Russian Garden (40°C), and the Yesha well (53-65°C). These temperatures may encourage further developments for spas and bathing installations and, to a limited extent, for space heating, but are not favorable for geothermal power generation.

  5. Aluto-Langano geothermal field, Ethiopian Rift Valley: Physical characteristics and the effects of gas on well performance

    SciTech Connect

    Gizaw, B. )

    1993-04-01

    This study, which focuses on the Aluto-Langano geothermal field, is part of the ongoing investigation of the geothermal systems in the Ethiopian Rift Valley. Aluto-Langano is a water-dominated gas-rich geothermal field, with a maximum temperature close to 360[degree]C, in the Lakes District region of the Ethiopian Rift Valley. The upflow zone for the system lies along a deep, young NNE trending fault and is characterized by boiling. As a result, the deep upflow zone loses some water as steam and produces a cooler saline shallow aquifer. The high partial pressure of carbon dioxide (about 30 bar in the reservoir) depresses the water table and restricts boiling to deeper levels. The main aquifer for the systems is in the Tertiary ignimbrite, which lies below 1400 m. The capacity of the existing wells is close to 7 MW[sub c]: the energy potential of the area is estimated to be between 3000 and 6000 MW[sub t] yr/km[sup 3], or 10-20 MW[sub c]/km[sup 3] for over 30 years.

  6. Prevalence of contagious caprine pleuro-pneumonia in pastoral flocks of goats in the Rift Valley region of Kenya.

    PubMed

    Kipronoh, Alexander Kipruto; Ombui, Jackson Nyarongi; Kiara, Henry Kimathi; Binepal, Yatinder Singh; Gitonga, Eric; Wesonga, Hezron Okwako

    2016-01-01

    A cross-sectional survey was conducted between the months of March 2014 and March 2015 to determine the prevalence of contagious caprine pleuropneumonia in goat populations in pastoral flocks in three sub-counties of the Rift Valley region. A total of 432 serum samples were collected from goats from 54 flocks and tested for the presence of antibodies against mycoplasma capricolum subspecies capripneumoniae (mccp) using monoclonal antibody-based competitive enzyme-linked immuno-sorbent assay. Sero-prevalence recorded for Turkana West was 63.9%, Kajiado Central was 48.6%, while Pokot East was 29.2% which was statistically significant (χ2 = 34.997; P = 0.000) in the study sites. The results of this study confirmed that CCPP is widespread and endemic in the pastoral production systems studied in the Rift Valley region. The results confirmed that regions sharing international boundaries are at a higher risk of CCPP hence the need for a unified cross-border approach to disease control measures in the border areas. PMID:26516086

  7. Serological evidence in sheep suggesting phlebovirus circulation in a Rift Valley fever enzootic area in Burkina Faso.

    PubMed

    Gonzalez, J P; Le Guenno, B; Some, M J; Akakpo, J A

    1992-01-01

    Within the Phlebovirus serogroup, Rift Valley fever (RVF) virus is endemo-enzootic in the African sahelian zone. Recently an RVF epizootic in West Africa prompted a serosurvey in the major sheep and cattle raising areas. Because of the close antigenic relationship between the phleboviruses it appeared of interest to evaluate the prevalence of the other phleboviruses also. In 1987, 482 sheep serum samples were collected in 2 different ecological zones of Burkina Faso and tested for the presence of phlebovirus antibodies. A sensitive but non-specific immunofluorescent antibody test and a specific enzyme-linked immunosorbent assay (ELISA) were used, with the following African phlebovirus antigens: Rift Valley fever (RVF), Arumowot, Gabek Forest, Gordil, Saint Floris and Odrenisrou. A total of 15.8% of the sera sampled had anti-RVF antibody in the ELISA. RVF virus appeared to be more active in drier areas such as the sahelian region, known to be an enzootic area for the disease. Antibodies to other phleboviruses were found in 11.8% of the samples, independent of RVF virus activity. It is assumed that sheep can be infected by different phleboviruses. PMID:1287944

  8. Hydrothermal circulation, serpentinization, and degassing at a rift valley-fracture zone intersection: Mid-Atlantic Ridge near 15[degree]N, 45[degree]W

    SciTech Connect

    Rona, P.A.; Nelson, T.A. ); Bougault, H.; Charlou, J.L.; Needham, H.D. ); Appriou, P. ); Trefry, J.H. ); Eberhart, G.L.; Barone, A. )

    1992-09-01

    A hydrothermal system characterized by high ratios of methane to both manganese and suspended particulate matter was detected in seawater sampled at the eastern intersection of the rift valley of the Mid-Atlantic Ridge with the Fifteen-Twenty Fracture Zone. This finding contrasts with low ratios in black smoker-type hydrothermal systems that occur within spreading segments. Near-bottom water sampling coordinated with SeaBeam bathymetry and camera-temperature tows detected the highest concentrations of methane at fault zones in rocks with the appearance of altered ultramafic units in a large dome that forms part of the inside corner high at the intersection. The distinct chemical signatures of the two types of hydrothermal systems are inferred to be controlled by different circulation pathways related to reaction of seawater primarily with ultramafic rocks at intersections of spreading segments with fracture zones but with mafic rocks within spreading segments.

  9. N-Glycans on the Rift Valley Fever Virus Envelope Glycoproteins Gn and Gc Redundantly Support Viral Infection via DC-SIGN.

    PubMed

    Phoenix, Inaia; Nishiyama, Shoko; Lokugamage, Nandadeva; Hill, Terence E; Huante, Matthew B; Slack, Olga A L; Carpio, Victor H; Freiberg, Alexander N; Ikegami, Tetsuro

    2016-01-01

    Rift Valley fever is a mosquito-transmitted, zoonotic disease that infects humans and ruminants. Dendritic cell specific intercellular adhesion molecule 3 (ICAM-3) grabbing non-integrin (DC-SIGN) acts as a receptor for members of the phlebovirus genus. The Rift Valley fever virus (RVFV) glycoproteins (Gn/Gc) encode five putative N-glycan sequons (asparagine (N)-any amino acid (X)-serine (S)/threonine (T)) at positions: N438 (Gn), and N794, N829, N1035, and N1077 (Gc). The N-glycosylation profile and significance in viral infection via DC-SIGN have not been elucidated. Gc N-glycosylation was first evaluated by using Gc asparagine (N) to glutamine (Q) mutants. Subsequently, we generated a series of recombinant RVFV MP-12 strain mutants, which encode N-to-Q mutations, and the infectivity of each mutant in Jurkat cells stably expressing DC-SIGN was evaluated. Results showed that Gc N794, N1035, and N1077 were N-glycosylated but N829 was not. Gc N1077 was heterogeneously N-glycosylated. RVFV Gc made two distinct N-glycoforms: "Gc-large" and "Gc-small", and N1077 was responsible for "Gc-large" band. RVFV showed increased infection of cells expressing DC-SIGN compared to cells lacking DC-SIGN. Infection via DC-SIGN was increased in the presence of either Gn N438 or Gc N1077. Our study showed that N-glycans on the Gc and Gn surface glycoproteins redundantly support RVFV infection via DC-SIGN. PMID:27223297

  10. Evaluation of efficacy, potential for vector transmission and duration of immunity testing of MP-12, an attenuated Rift Valley fever virus vaccine candidate, in sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rift Valley fever virus (RVFV) causes serious disease in ruminants and humans in Africa. There are currently no fully licensed vaccines for this arthropod-borne virus in the US. Studies in sheep and cattle have found an attenuated strain of RVFV, MP-12, to be both safe and efficacious, and a conditi...