Population-genomic insights into emergence, crop adaptation and dissemination of Pseudomonas syringae pathogens

PubMed Central

Monteil, Caroline L.; Yahara, Koji; Studholme, David J.; Mageiros, Leonardos; Méric, Guillaume; Swingle, Bryan; Morris, Cindy E.

2016-01-01

Many bacterial pathogens are well characterized but, in some cases, little is known about the populations from which they emerged. This limits understanding of the molecular mechanisms underlying disease. The crop pathogen Pseudomonas syringae sensu lato has been widely isolated from the environment, including wild plants and components of the water cycle, and causes disease in several economically important crops. Here, we compared genome sequences of 45 P. syringae crop pathogen outbreak strains with 69 closely related environmental isolates. Phylogenetic reconstruction revealed that crop pathogens emerged many times independently from environmental populations. Unexpectedly, differences in gene content between environmental populations and outbreak strains were minimal with most virulence genes present in both. However, a genome-wide association study identified a small number of genes, including the type III effector genes hopQ1 and hopD1, to be associated with crop pathogens, but not with environmental populations, suggesting that this small group of genes may play an important role in crop disease emergence. Intriguingly, genome-wide analysis of homologous recombination revealed that the locus Psyr 0346, predicted to encode a protein that confers antibiotic resistance, has been frequently exchanged among lineages and thus may contribute to pathogen fitness. Finally, we found that isolates from diseased crops and from components of the water cycle, collected during the same crop disease epidemic, form a single population. This provides the strongest evidence yet that precipitation and irrigation water are an overlooked inoculum source for disease epidemics caused by P. syringae. PMID:28348830

Population-genomic insights into emergence, crop adaptation and dissemination of Pseudomonas syringae pathogens.

PubMed

Monteil, Caroline L; Yahara, Koji; Studholme, David J; Mageiros, Leonardos; Méric, Guillaume; Swingle, Bryan; Morris, Cindy E; Vinatzer, Boris A; Sheppard, Samuel K

2016-10-01

Many bacterial pathogens are well characterized but, in some cases, little is known about the populations from which they emerged. This limits understanding of the molecular mechanisms underlying disease. The crop pathogen Pseudomonas syringae sensu lato has been widely isolated from the environment, including wild plants and components of the water cycle, and causes disease in several economically important crops. Here, we compared genome sequences of 45 P. syringae crop pathogen outbreak strains with 69 closely related environmental isolates. Phylogenetic reconstruction revealed that crop pathogens emerged many times independently from environmental populations. Unexpectedly, differences in gene content between environmental populations and outbreak strains were minimal with most virulence genes present in both. However, a genome-wide association study identified a small number of genes, including the type III effector genes hopQ1 and hopD1 , to be associated with crop pathogens, but not with environmental populations, suggesting that this small group of genes may play an important role in crop disease emergence. Intriguingly, genome-wide analysis of homologous recombination revealed that the locus Psyr 0346, predicted to encode a protein that confers antibiotic resistance, has been frequently exchanged among lineages and thus may contribute to pathogen fitness. Finally, we found that isolates from diseased crops and from components of the water cycle, collected during the same crop disease epidemic, form a single population. This provides the strongest evidence yet that precipitation and irrigation water are an overlooked inoculum source for disease epidemics caused by P. syringae .

Resiliency or restoration: management of sudden oak death before and after outbreak

Treesearch

Richard Cobb; Peter Hartsough; Noam Ross; Janet Klein; David LaFever; Susan Frankel; David Rizzo

2017-01-01

Forests at risk to diseases caused by invasive Phytophthora pathogens can be grouped into two broad classes: those already invaded by the focal pathogen where disease has emerged or those at significant risk of invasion and subsequent emergence of disease. This dichotomy represents distinct management scenarios – treating after or before disease...

Draft Genome Sequence of Rhodotorula mucilaginosa, an Emergent Opportunistic Pathogen

PubMed Central

Deligios, Massimo; Fraumene, Cristina; Abbondio, Marcello; Mannazzu, Ilaria; Tanca, Alessandro; Addis, Maria Filippa

2015-01-01

Rhodotorula mucilaginosa, a yeast with valuable biotechnological features, has also been recorded as an emergent opportunistic pathogen that might cause disease in both immunocompetent and immunocompromised individuals. Here, we report the draft genome sequence of R. mucilaginosa strain C2.5t1, which was isolated from cacao seeds in Cameroon. PMID:25858834

Deciphering microbial landscapes of fish eggs to mitigate emerging disease

USDA-ARS?s Scientific Manuscript database

Animals and plants are increasingly suffering from diseases caused by fungi and oomycetes. These emerging pathogens are now recognised as a global threat to biodiversity and food security. Amongst oomycetes, Saprolegnia species cause significant declines in fish and amphibian populations. Fish eggs ...

Emerging and Reemerging Neurologic Infections

PubMed Central

Glaser, Carol A.

2014-01-01

The list of emerging and reemerging pathogens that cause neurologic disease is expanding. Various factors, including population growth and a rise in international travel, have contributed to the spread of pathogens to previously nonendemic regions. Recent advances in diagnostic methods have led to the identification of novel pathogens responsible for infections of the central nervous system. Furthermore, new issues have arisen surrounding established infections, particularly in an increasingly immunocompromised population due to advances in the treatment of rheumatologic disease and in transplant medicine. PMID:25360203

Newly emerged populations of Plasmopara halstedii infecting rudbeckia exhibit unique genotypic profiles and are distinct from sunflower-infecting strains

USDA-ARS?s Scientific Manuscript database

The oomycete Plasmopara halstedii emerged at the onset of the 21st century as a destructive new pathogen causing downy mildew disease of ornamental Rudbeckia fulgida (rudbeckia) in the U.S.A. The pathogen is also a significant global problem of sunflower (Helianthus annuus), and is widely regarded a...

Adaption of wild-bird origin H5Nx highly pathogenic avian influenza virus Clade 2.3.4.4 in vaccinated poultry

USDA-ARS?s Scientific Manuscript database

The 2014-2015 incursion of H5Nx clade 2.3.4.4 high pathogenicity avian influenza (HPAI) virus caused the largest animal health emergency in U.S. history and renewed interest in developing vaccines against these newly emergent viruses. Our previous research demonstrated several H5 vaccines with varyi...

Multiplex and label-free screening of foodborne pathogens using surface plasmon resonance imaging

USDA-ARS?s Scientific Manuscript database

In order to protect outbreaks caused by foodborne pathogens, more rapid and efficient methods are needed for pathogen screening from food samples. Surface plasmon resonance imaging (SPRi) is an emerging optical technique, which allows for label-free screening of multiple targets simultaneously with ...

Emergence of pathogenic and multiple-antibiotic-resistant Macrococcus caseolyticus in commercial broiler chickens.

PubMed

Li, Gen; Du, Xusheng; Zhou, Defang; Li, Chengui; Huang, Libo; Zheng, Qiankun; Cheng, Ziqiang

2018-05-25

Macrococcus caseolyticus is generally considered to be a non-pathogenic bacterium that does not cause human or animal diseases. However, recently, a strain of M. caseolyticus (SDLY strain) that causes high mortality rates was isolated from commercial broiler chickens in China. The main pathological changes caused by SDLY included caseous exudation in cranial cavities, inflammatory infiltration, haemorrhages and multifocal necrosis in various organs. The whole genome of the SDLY strain was sequenced and was compared with that of the non-pathogenic JCSC5402 strain of M. caseolyticus. The results showed that the SDLY strain harboured a large quantity of mutations, antibiotic resistance genes and numerous insertions and deletions of virulence genes. In particular, among the inserted genes, there is a cluster of eight connected genes associated with the synthesis of capsular polysaccharide. This cluster encodes a transferase and capsular polysaccharide synthase, promotes the formation of capsules and causes changes in pathogenicity. Electron microscopy revealed a distinct capsule surrounding the SDLY strain. The pathogenicity test showed that the SDLY strain could cause significant clinical symptoms and pathological changes in both SPF chickens and mice. In addition, these clinical symptoms and pathological changes were the same as those observed in field cases. Furthermore, the anti-microbial susceptibility test demonstrated that the SDLY strain exhibits multiple-antibiotic resistance. The emergence of pathogenic M. caseolyticus indicates that more attention should be paid to the effects of this micro-organism on both poultry and public health. © 2018 Blackwell Verlag GmbH.

Developing Zika vaccines: the lessons for disease X.

PubMed

Barrett, Alan D T

2018-06-26

There is an urgent need to develop vaccines against emerging diseases, including those caused by pathogens that are currently unknown to cause human disease, termed 'disease X'. Here, Zika virus infection is considered as an example of disease X. The speed of Zika vaccine development provides optimism for our ability to prepare vaccines against unknown pathogens.

Global and local environmental changes as drivers of Buruli ulcer emergence.

PubMed

Combe, Marine; Velvin, Camilla Jensen; Morris, Aaron; Garchitorena, Andres; Carolan, Kevin; Sanhueza, Daniel; Roche, Benjamin; Couppié, Pierre; Guégan, Jean-François; Gozlan, Rodolphe Elie

2017-04-26

Many emerging infectious diseases are caused by generalist pathogens that infect and transmit via multiple host species with multiple dissemination routes, thus confounding the understanding of pathogen transmission pathways from wildlife reservoirs to humans. The emergence of these pathogens in human populations has frequently been associated with global changes, such as socio-economic, climate or biodiversity modifications, by allowing generalist pathogens to invade and persist in new ecological niches, infect new host species, and thus change the nature of transmission pathways. Using the case of Buruli ulcer disease, we review how land-use changes, climatic patterns and biodiversity alterations contribute to disease emergence in many parts of the world. Here we clearly show that Mycobacterium ulcerans is an environmental pathogen characterized by multi-host transmission dynamics and that its infectious pathways to humans rely on the local effects of global environmental changes. We show that the interplay between habitat changes (for example, deforestation and agricultural land-use changes) and climatic patterns (for example, rainfall events), applied in a local context, can lead to abiotic environmental changes and functional changes in local biodiversity that favor the pathogen's prevalence in the environment and may explain disease emergence.

Parasitic, fungal and prion zoonoses: an expanding universe of candidates for human disease.

PubMed

Akritidis, N

2011-03-01

Zoonotic infections have emerged as a burden for millions of people in recent years, owing to re-emerging or novel pathogens often causing outbreaks in the developing world in the presence of inadequate public health infrastructure. Among zoonotic infections, those caused by parasitic pathogens are the ones that affect millions of humans worldwide, who are also at risk of developing chronic disease. The present review discusses the global effect of protozoan pathogens such as Leishmania sp., Trypanosoma sp., and Toxoplasma sp., as well as helminthic pathogens such as Echinococcus sp., Fasciola sp., and Trichinella sp. The zoonotic aspects of agents that are not essentially zoonotic are also discussed. The review further focuses on the zoonotic dynamics of fungal pathogens and prion diseases as observed in recent years, in an evolving environment in which novel patient target groups have developed for agents that were previously considered to be obscure or of minimal significance. © 2011 The Author. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.

Phylogenetic Analysis and Antimicrobial Profiles of Cultured Emerging Opportunistic Pathogens (Phyla Actinobacteria and Proteobacteria) Identified in Hot Springs.

PubMed

Jardine, Jocelyn Leonie; Abia, Akebe Luther King; Mavumengwana, Vuyo; Ubomba-Jaswa, Eunice

2017-09-15

Hot spring water may harbour emerging waterborne opportunistic pathogens that can cause infections in humans. We have investigated the diversity and antimicrobial resistance of culturable emerging and opportunistic bacterial pathogens, in water and sediment of hot springs located in Limpopo, South Africa. Aerobic bacteria were cultured and identified using 16S ribosomal DNA (rDNA) gene sequencing. The presence of Legionella spp. was investigated using real-time polymerase chain reaction. Isolates were tested for resistance to ten antibiotics representing six different classes: β-lactam (carbenicillin), aminoglycosides (gentamycin, kanamycin, streptomycin), tetracycline, amphenicols (chloramphenicol, ceftriaxone), sulphonamides (co-trimoxazole) and quinolones (nalidixic acid, norfloxacin). Gram-positive Kocuria sp. and Arthrobacter sp. and gram-negative Cupriavidus sp., Ralstonia sp., Cronobacter sp., Tepidimonas sp., Hafnia sp. and Sphingomonas sp. were isolated, all recognised as emerging food-borne pathogens. Legionella spp. was not detected throughout the study. Isolates of Kocuria , Arthrobacter and Hafnia and an unknown species of the class Gammaproteobacteria were resistant to two antibiotics in different combinations of carbenicillin, ceftriaxone, nalidixic acid and chloramphenicol. Cronobacter sp. was sensitive to all ten antibiotics. This study suggests that hot springs are potential reservoirs for emerging opportunistic pathogens, including multiple antibiotic resistant strains, and highlights the presence of unknown populations of emerging and potential waterborne opportunistic pathogens in the environment.

Community-acquired methicillin-resistant Staphylococcus aureus: an emerging cause of acute bacterial parotitis.

PubMed

Nicolasora, Nelson P; Zacharek, Mark A; Malani, Anurag N

2009-02-01

Staphylococcus aureus has long been recognized as a cause of acute bacterial parotitis. A case of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) parotitis is presented, highlighting the emergence of this increasingly important pathogen to cause a wide variety of infections. Also reviewed are the salient clinical and microbiologic features of this novel infection.

Chimpanzee adenoviral vectors as vaccines for outbreak pathogens

PubMed Central

2017-01-01

ABSTRACT The 2014–15 Ebola outbreak in West Africa highlighted the potential for large disease outbreaks caused by emerging pathogens and has generated considerable focus on preparedness for future epidemics. Here we discuss drivers, strategies and practical considerations for developing vaccines against outbreak pathogens. Chimpanzee adenoviral (ChAd) vectors have been developed as vaccine candidates for multiple infectious diseases and prostate cancer. ChAd vectors are safe and induce antigen-specific cellular and humoral immunity in all age groups, as well as circumventing the problem of pre-existing immunity encountered with human Ad vectors. For these reasons, such viral vectors provide an attractive platform for stockpiling vaccines for emergency deployment in response to a threatened outbreak of an emerging pathogen. Work is already underway to develop vaccines against a number of other outbreak pathogens and we will also review progress on these approaches here, particularly for Lassa fever, Nipah and MERS. PMID:29083948

Spectrum of Viral Pathogens in Blood of Malaria-Free Ill Travelers Returning to Canada.

PubMed

Kariyawasam, Ruwandi; Lau, Rachel; Eshaghi, Alireza; Patel, Samir N; Sider, Doug; Gubbay, Jonathan B; Boggild, Andrea K

2016-05-01

Malaria is the most common specific cause of fever in returning travelers, but many other vectorborne infections and viral infections are emerging and increasingly encountered by travelers. We documented common and emerging viral pathogens in malaria-negative specimens from ill travelers returning to Canada. Anonymized, malaria-negative specimens were examined for various viral pathogens by real-time PCR. Samples were positive for herpes simplex viruses 1 or 2 (n = 21, 1.6%), cytomegalovirus (n = 4, 0.3%), Epstein-Barr virus (n = 194, 14.9%), dengue virus types 1-4 (n = 27, 2.1%), chikungunya virus (n = 5, 0.4%), and hepatitis A virus (n = 12, 0.9%). Travel-acquired viral pathogens were documented in >20% of malaria-negative specimens, of which 2.5% were infected with dengue and chikungunya viruses. Our findings support the anecdotal impression that these vectorborne pathogens are emerging among persons who travel from Canada to other countries.

New trends in emerging pathogens.

PubMed

Skovgaard, Niels

2007-12-15

The emergence of pathogens is the result of a number of impact in all parts of the food chain. The emerging technologies in food production explain how new pathogens can establish themselves in the food chain and compromise food safety. The impact of the food technology is analysed for several bacteria, such as Yersinia, Campylobacter, Arcobacter, Helicobacter pullorum, Enterobacter sakazakii, Mycobacterium avium spp. paratuberculosis, prions related to vCJD and others. The importance of the ability of many microbes to form VBNC forms is elaborated on. Research on culture independent methods may address this outstanding issue to the better understanding of emerging pathogens. The "demerging" of pathogens also occur, and examples of this are explained. The reaction of bacteria to stresses and sublethal treatments, and how exposure to one stress factor can confer resistance to other stresses, literally speaking causing contagious resistance, are explained. The implication of this e.g. in modern approaches of food preservation, such as Minimally processed Foods, is considerable. Intestinal colonization of EHEC may be regulated by Quorum sensing, and this ability of microbes plays an important role in the colonization of microbes in food and on food processing equipment, an important factor in the emergence of pathogens. The emergence of Saccharomyces cerevisiae, as an opportunistic human pathogen, used for centuries for food and production of alcoholic beverages, calls for research in molecular tools to distinguish between probiotic and clinical strains. Cyclospora cayetanensis and Norovirus outbreaks can no longer be designated as emerging pathogens, they share however one characteristic in the epidemiology of emerging nature, the importance of the hygiene in the primary production stage, including supply of potable water, and the application of GMP and the HACCP principles in the beginning of the food chain. Hepatitis E virus is a potential emerging food borne pathogen and swine may serve as a source of infection in human, a most challenging issue in greater part of the world raising pigs. Tick-borne encephalitis virus infection, either thick borne or caused by consumption of raw milk, is an increasing trend in the industrialized part of the world. Consumer awareness, ethics of food, sustainability in food production, and trust in foods, are of growing importance to the consumer. The reaction of the consumer to new technology, such as nanotechnology, is unpredictable. Many efforts should be devoted to communication of non-biased information to both the food producers as well as the consumer.

Emerging oomycete threats to plants and animals

PubMed Central

Chaparro-Garcia, Angela

2016-01-01

Oomycetes, or water moulds, are fungal-like organisms phylogenetically related to algae. They cause devastating diseases in both plants and animals. Here, we describe seven oomycete species that are emerging or re-emerging threats to agriculture, horticulture, aquaculture and natural ecosystems. They include the plant pathogens Phytophthora infestans, Phytophthora palmivora, Phytophthora ramorum, Plasmopara obducens, and the animal pathogens Aphanomyces invadans, Saprolegnia parasitica and Halioticida noduliformans. For each species, we describe its pathology, importance and impact, discuss why it is an emerging threat and briefly review current research activities. This article is part of the themed issue ‘Tackling emerging fungal threats to animal health, food security and ecosystem resilience’. PMID:28080985

Emerging tick-borne infections in mainland China: an increasing public health threat

PubMed Central

Li, Xin-Lou; Liang, Song; Yang, Yang; Yao, Hong-Wu; Sun, Ruo-Xi; Sun, Ye; Chen, Wan-Jun; Zuo, Shu-Qing; Ma, Mai-Juan; Li, Hao; Jiang, Jia-Fu; Liu, Wei; Yang, X Frank; Gray, Gregory C; Krause, Peter J; Cao, Wu-Chun

2016-01-01

Since the beginning of the 1980s, 33 emerging tick-borne agents have been identified in mainland China, including eight species of spotted fever group rickettsiae, seven species in the family Anaplasmataceae, six genospecies in the complex Borrelia burgdorferi sensu lato, 11 species of Babesia, and the virus causing severe fever with thrombocytopenia syndrome. In this Review we have mapped the geographical distributions of human cases of infection. 15 of the 33 emerging tick-borne agents have been reported to cause human disease, and their clinical characteristics have been described. The non-specific clinical manifestations caused by tick-borne pathogens present a major diagnostic challenge and most physicians are unfamiliar with the many tick-borne diseases that present with non-specific symptoms in the early stages of the illness. Advances in and application of modern molecular techniques should help with identification of emerging tick-borne pathogens and improve laboratory diagnosis of human infections. We expect that more novel tick-borne infections in ticks and animals will be identified and additional emerging tick-borne diseases in human beings will be discovered. PMID:26453241

Five Reasons to Consider Phytophthora infestans a Reemerging Pathogen.

PubMed

Fry, W E; Birch, P R J; Judelson, H S; Grünwald, N J; Danies, G; Everts, K L; Gevens, A J; Gugino, B K; Johnson, D A; Johnson, S B; McGrath, M T; Myers, K L; Ristaino, J B; Roberts, P D; Secor, G; Smart, C D

2015-07-01

Phytophthora infestans has been a named pathogen for well over 150 years and yet it continues to "emerge", with thousands of articles published each year on it and the late blight disease that it causes. This review explores five attributes of this oomycete pathogen that maintain this constant attention. First, the historical tragedy associated with this disease (Irish potato famine) causes many people to be fascinated with the pathogen. Current technology now enables investigators to answer some questions of historical significance. Second, the devastation caused by the pathogen continues to appear in surprising new locations or with surprising new intensity. Third, populations of P. infestans worldwide are in flux, with changes that have major implications to disease management. Fourth, the genomics revolution has enabled investigators to make tremendous progress in terms of understanding the molecular biology (especially the pathogenicity) of P. infestans. Fifth, there remain many compelling unanswered questions.

Bactericidal assessment of nano-silver on emerging and re-emerging human pathogens.

PubMed

Anuj, Samir A; Gajera, Harsukh P; Hirpara, Darshna G; Golakiya, Baljibhai A

2018-04-24

With the threat of the growing number of bacteria resistant to antibiotics, the re-emergence of previously deadly infections and the emergence of new infections, there is an urgent need for novel therapeutic agent. Silver in the nano form, which is being used increasingly as antibacterial agents, may extend its antibacterial application to emerging and re-emerging multidrug-resistant pathogens, the main cause of nosocomial diseases worldwide. In the present study, a completely bottom up method to prepare green nano-silver was used. To explore the action of nano-silver on emerging Bacillus megaterium MTCC 7192 and re-emerging Pseudomonas aeruginosa MTCC 741 pathogenic bacteria, the study includes an analysis of the bacterial membrane damage through Scanning Electron Microscope (SEM) as well as alternation of zeta potential and intracellular leakages. In this work, we observed genuine bactericidal property of nano-silver as compare to broad spectrum antibiotics against emerging and re-emerging mode. After being exposed to nano-silver, the membrane becomes scattered from their original ordered arrangement based on SEM observation. Moreover, our results also suggested that alternation of zeta potential enhanced membrane permeability, and beyond a critical point, it leads to cell death. The leakages of intracellular constituents were confirmed by Gas Chromatography-Mass Spectrometry (GC-MS). In conclusion, the combine results suggested that at a specific dose, nano-silver may destroy the structure of bacterial membrane and depress its activity, which causes bacteria to die eventually. Copyright © 2018 Elsevier GmbH. All rights reserved.

Phylogenetic Analysis and Antimicrobial Profiles of Cultured Emerging Opportunistic Pathogens (Phyla Actinobacteria and Proteobacteria) Identified in Hot Springs

PubMed Central

Jardine, Jocelyn Leonie; Mavumengwana, Vuyo

2017-01-01

Hot spring water may harbour emerging waterborne opportunistic pathogens that can cause infections in humans. We have investigated the diversity and antimicrobial resistance of culturable emerging and opportunistic bacterial pathogens, in water and sediment of hot springs located in Limpopo, South Africa. Aerobic bacteria were cultured and identified using 16S ribosomal DNA (rDNA) gene sequencing. The presence of Legionella spp. was investigated using real-time polymerase chain reaction. Isolates were tested for resistance to ten antibiotics representing six different classes: β-lactam (carbenicillin), aminoglycosides (gentamycin, kanamycin, streptomycin), tetracycline, amphenicols (chloramphenicol, ceftriaxone), sulphonamides (co-trimoxazole) and quinolones (nalidixic acid, norfloxacin). Gram-positive Kocuria sp. and Arthrobacter sp. and gram-negative Cupriavidus sp., Ralstonia sp., Cronobacter sp., Tepidimonas sp., Hafnia sp. and Sphingomonas sp. were isolated, all recognised as emerging food-borne pathogens. Legionella spp. was not detected throughout the study. Isolates of Kocuria, Arthrobacter and Hafnia and an unknown species of the class Gammaproteobacteria were resistant to two antibiotics in different combinations of carbenicillin, ceftriaxone, nalidixic acid and chloramphenicol. Cronobacter sp. was sensitive to all ten antibiotics. This study suggests that hot springs are potential reservoirs for emerging opportunistic pathogens, including multiple antibiotic resistant strains, and highlights the presence of unknown populations of emerging and potential waterborne opportunistic pathogens in the environment. PMID:28914802

Transcriptome Remodeling Contributes to Epidemic Disease Caused by the Human Pathogen Streptococcus pyogenes.

PubMed

Beres, Stephen B; Kachroo, Priyanka; Nasser, Waleed; Olsen, Randall J; Zhu, Luchang; Flores, Anthony R; de la Riva, Ivan; Paez-Mayorga, Jesus; Jimenez, Francisco E; Cantu, Concepcion; Vuopio, Jaana; Jalava, Jari; Kristinsson, Karl G; Gottfredsson, Magnus; Corander, Jukka; Fittipaldi, Nahuel; Di Luca, Maria Chiara; Petrelli, Dezemona; Vitali, Luca A; Raiford, Annessa; Jenkins, Leslie; Musser, James M

2016-05-31

For over a century, a fundamental objective in infection biology research has been to understand the molecular processes contributing to the origin and perpetuation of epidemics. Divergent hypotheses have emerged concerning the extent to which environmental events or pathogen evolution dominates in these processes. Remarkably few studies bear on this important issue. Based on population pathogenomic analysis of 1,200 Streptococcus pyogenes type emm89 infection isolates, we report that a series of horizontal gene transfer events produced a new pathogenic genotype with increased ability to cause infection, leading to an epidemic wave of disease on at least two continents. In the aggregate, these and other genetic changes substantially remodeled the transcriptomes of the evolved progeny, causing extensive differential expression of virulence genes and altered pathogen-host interaction, including enhanced immune evasion. Our findings delineate the precise molecular genetic changes that occurred and enhance our understanding of the evolutionary processes that contribute to the emergence and persistence of epidemically successful pathogen clones. The data have significant implications for understanding bacterial epidemics and for translational research efforts to blunt their detrimental effects. The confluence of studies of molecular events underlying pathogen strain emergence, evolutionary genetic processes mediating altered virulence, and epidemics is in its infancy. Although understanding these events is necessary to develop new or improved strategies to protect health, surprisingly few studies have addressed this issue, in particular, at the comprehensive population genomic level. Herein we establish that substantial remodeling of the transcriptome of the human-specific pathogen Streptococcus pyogenes by horizontal gene flow and other evolutionary genetic changes is a central factor in precipitating and perpetuating epidemic disease. The data unambiguously show that the key outcome of these molecular events is evolution of a new, more virulent pathogenic genotype. Our findings provide new understanding of epidemic disease. Copyright © 2016 Beres et al.

An emergent disease causes directional changes in forest species composition in coastal California

Treesearch

Margaret Metz; Kerri Frangioso; Allison Wickland; Ross Meentemeyer; David Rizzo

2012-01-01

Non-native forest pathogens can cause dramatic and long-lasting changes to the composition of forests, and these changes may have cascading impacts on community interactions and ecosystem functioning. Phytophthora ramorum, the causal agent of the emergent forest disease sudden oak death (SOD), has a wide host range, but mortality is concentrated in...

Contrasting introduction scenarios among continents in the worldwide invasion of the banana fungal pathogen Mycosphaerella fijiensis.

PubMed

Robert, S; Ravigne, V; Zapater, M-F; Abadie, C; Carlier, J

2012-03-01

Reconstructing and characterizing introduction routes is a key step towards understanding the ecological and evolutionary factors underlying successful invasions and disease emergence. Here, we aimed to decipher scenarios of introduction and stochastic demographic events associated with the global spread of an emerging disease of bananas caused by the destructive fungal pathogen Mycosphaerella fijiensis. We analysed the worldwide population structure of this fungus using 21 microsatellites and 8 sequence-based markers on 735 individuals from 37 countries. Our analyses designated South-East Asia as the source of the global invasion and supported the location of the centre of origin of M. fijiensis within this area. We confirmed the occurrence of bottlenecks upon introduction into other continents followed by widespread founder events within continents. Furthermore, this study suggested contrasting introduction scenarios of the pathogen between the African and American continents. While potential signatures of admixture resulting from multiple introductions were detected in America, all the African samples examined seem to descend from a single successful founder event. In combination with historical information, our study reveals an original and unprecedented global scenario of invasion for this recently emerging disease caused by a wind-dispersed pathogen. © 2012 Blackwell Publishing Ltd.

Enteroaggregative Escherichia coli: An Emerging Enteric Food Borne Pathogen.

PubMed

Kaur, P; Chakraborti, A; Asea, A

2010-01-01

Enteroaggregative Escherichia coli (EAEC) are quite heterogeneous category of an emerging enteric pathogen associated with cases of acute or persistent diarrhea worldwide in children and adults, and over the past decade has received increasing attention as a cause of watery diarrhea, which is often persistent. EAEC infection is an important cause of diarrhea in outbreak and non-outbreak settings in developing and developed countries. Recently, EAEC has been implicated in the development of irritable bowel syndrome, but this remains to be confirmed. EAEC is defined as a diarrheal pathogen based on its characteristic aggregative adherence (AA) to HEp-2 cells in culture and its biofilm formation on the intestinal mucosa with a "stacked-brick" adherence phenotype, which is related to the presence of a 60 MDa plasmid (pAA). At the molecular level, strains demonstrating the aggregative phenotype are quite heterogeneous; several virulence factors are detected by polymerase chain reaction; however, none exhibited 100% specificity. Although several studies have identified specific virulence factor(s) unique to EAEC, the mechanism by which EAEC exerts its pathogenesis is, thus, far unknown. The present review updates the current knowledge on the epidemiology, chronic complications, detection, virulence factors, and treatment of EAEC, an emerging enteric food borne pathogen.

Resistance in persisting bat populations after white-nose syndrome invasion.

PubMed

Langwig, Kate E; Hoyt, Joseph R; Parise, Katy L; Frick, Winifred F; Foster, Jeffrey T; Kilpatrick, A Marm

2017-01-19

Increases in anthropogenic movement have led to a rise in pathogen introductions and the emergence of infectious diseases in naive host communities worldwide. We combined empirical data and mathematical models to examine changes in disease dynamics in little brown bat (Myotis lucifugus) populations following the introduction of the emerging fungal pathogen Pseudogymnoascus destructans, which causes the disease white-nose syndrome. We found that infection intensity was much lower in persisting populations than in declining populations where the fungus has recently invaded. Fitted models indicate that this is most consistent with a reduction in the growth rate of the pathogen when fungal loads become high. The data are inconsistent with the evolution of tolerance or an overall reduced pathogen growth rate that might be caused by environmental factors. The existence of resistance in some persisting populations of little brown bats offers a glimmer of hope that a precipitously declining species will persist in the face of this deadly pathogen.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'. © 2016 The Author(s).

Coinfection by the tick-borne pathogens Babesia microti and Borrelia burgdorferi: ecological, epidemiological and clinical consequences

PubMed Central

Diuk-Wasser, Maria A.; Vannier, Edouard

2015-01-01

Ixodes ticks maintain a large and diverse array of human pathogens in the enzootic cycle, including Borrelia burgdorferi and Babesia microti. Despite the poor ecological fitness of B. microti, babesiosis has recently emerged in areas endemic for Lyme disease. Studies in ticks, reservoir hosts and humans indicate that coinfection with B. burgdorferi and B. microti is common, promotes transmission and emergence of B. microti in the enzootic cycle, and causes greater disease severity and duration in humans. These integrative studies may serve as a paradigm for the study of other vector-borne coinfections. Identifying ecological drivers of pathogen emergence and host factors that fuel disease severity will help guide the design of effective curative and prevention strategies. PMID:26613664

Novel Insights into Cell Entry of Emerging Human Pathogenic Arenaviruses.

PubMed

Fedeli, Chiara; Moreno, Héctor; Kunz, Stefan

2018-06-22

Viral hemorrhagic fevers caused by emerging RNA viruses of the Arenavirus family are among the most devastating human diseases. Climate change, global trade, and increasing urbanization promote the emergence and re-emergence of these human pathogenic viruses. Emerging pathogenic arenaviruses are of zoonotic origin and reservoir-to-human transmission is crucial for spillover into human populations. Host cell attachment and entry are the first and most fundamental steps of every virus infection and represent major barriers for zoonotic transmission. During host cell invasion, viruses critically depend on cellular factors, including receptors, co-receptors, and regulatory proteins of endocytosis. An in-depth understanding of the complex interaction of a virus with cellular factors implicated in host cell entry is therefore crucial to predict the risk of zoonotic transmission, define the tissue tropism, and assess disease potential. Over the past years, investigation of the molecular and cellular mechanisms underlying host cell invasion of human pathogenic arenaviruses uncovered remarkable viral strategies and provided novel insights into viral adaptation and virus-host co-evolution that will be covered in the present review. Copyright © 2018. Published by Elsevier Ltd.

Animal models of highly pathogenic RNA viral infections: encephalitis viruses.

PubMed

Holbrook, Michael R; Gowen, Brian B

2008-04-01

The highly pathogenic RNA viruses that cause encephalitis include a significant number of emerging or re-emerging viruses that are also considered potential bioweapons. Many of these viruses, including members of the family Flaviviridae, the genus Alphavirus in the family Togaviridae, and the genus Henipavirus in the family Paramyxoviridae, circulate widely in their endemic areas, where they are transmitted by mosquitoes or ticks. They use a variety of vertebrate hosts, ranging from birds to bats, in their natural life cycle. As was discovered in the United States, the introduction of a mosquito-borne encephalitis virus such as West Nile virus can cause significant health and societal concerns. There are no effective therapeutics for treating diseases caused by any of these viruses and there is limited, if any, vaccine availability for most. In this review we provide a brief summary of the current status of animal models used to study highly pathogenic encephalitic RNA viruses for the development of antiviral therapeutics and vaccines.

Post-translational modification of LipL32 during Leptospira interrogans infection

USDA-ARS?s Scientific Manuscript database

Leptospirosis, a re-emerging disease of global importance caused by pathogenic Leptospira spp., is considered the world’s most widespread zoonotic disease. Rats serve as asymptomatic carriers of pathogenic Leptospira and are critical for disease spread. In such reservoir hosts, leptospires colonize ...

The threat of emerging infections.

PubMed

1996-11-01

A variety of newly discovered pathogens and new forms of older infectious agents threaten to reemerge. Typical symptoms of acute infection are fever, headache, malaise, vomiting, and diarrhea. Some of the better-known emerging viral infections include dengue, filoviruses (Ebola, Marburg), hantaviruses, hepatitis B, hepatitis C, HIV, influenza, lassa fever, measles, rift valley fever, rotavirus, and yellow fever. Emerging bacterial infections include cholera, Escherichia coli 0157:H7, legionnaires disease (Legionella), lyme disease, streptococcus infections (group A), tuberculosis, and typhoid. Emerging parasitic infections include cryptosporidium and other waterborne pathogens and malaria. The causes of many diseases are still shrouded in mystery; thus, treatments and cures for them are as yet unknown.

Task 1.5 Genomic Shift and Drift Trends of Emerging Pathogens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borucki, M

2010-01-05

The Lawrence Livermore National Laboratory (LLNL) Bioinformatics group has recently taken on a role in DTRA's Transformation Medical Technologies Initiative (TMTI). The high-level goal of TMTI is to accelerate the development of broad-spectrum countermeasures. To achieve those goals, TMTI has a near term need to conduct analyses of genomic shift and drift trends of emerging pathogens, with a focused eye on select agent pathogens, as well as antibiotic and virulence markers. Most emerging human pathogens are zoonotic viruses with a genome composed of RNA. The high mutation rate of the replication enzymes of RNA viruses contributes to sequence drift andmore » provides one mechanism for these viruses to adapt to diverse hosts (interspecies transmission events) and cause new human and zoonotic diseases. Additionally, new viral pathogens frequently emerge due to genetic shift (recombination and segment reassortment) which allows for dramatic genotypic and phenotypic changes to occur rapidly. Bacterial pathogens also evolve via genetic drift and shift, although sequence drift generally occurs at a much slower rate for bacteria as compared to RNA viruses. However, genetic shift such as lateral gene transfer and inter- and intragenomic recombination enables bacteria to rapidly acquire new mechanisms of survival and antibiotic resistance. New technologies such as rapid whole genome sequencing of bacterial genomes, ultra-deep sequencing of RNA virus populations, metagenomic studies of environments rich in antibiotic resistance genes, and the use of microarrays for the detection and characterization of emerging pathogens provide mechanisms to address the challenges posed by the rapid emergence of pathogens. Bioinformatic algorithms that enable efficient analysis of the massive amounts of data generated by these technologies as well computational modeling of protein structures and evolutionary processes need to be developed to allow the technology to fulfill its potential.« less

Bacterial genomics reveal the complex epidemiology of an emerging pathogen in arctic and boreal ungulates

USGS Publications Warehouse

Forde, Taya L.; Orsel, Karin; Zadoks, Ruth N.; Biek, Roman; Adams, Layne G.; Checkley, Sylvia L.; Davison, Tracy; De Buck, Jeroen; Dumond, Mathieu; Elkin, Brett T.; Finnegan, Laura; Macbeth, Bryan J.; Nelson, Cait; Niptanatiak, Amanda; Sather, Shane; Schwantje, Helen M.; van der Meer, Frank; Kutz, Susan J.

2016-01-01

Northern ecosystems are currently experiencing unprecedented ecological change, largely driven by a rapidly changing climate. Pathogen range expansion, and emergence and altered patterns of infectious disease, are increasingly reported in wildlife at high latitudes. Understanding the causes and consequences of shifting pathogen diversity and host-pathogen interactions in these ecosystems is important for wildlife conservation, and for indigenous populations that depend on wildlife. Among the key questions are whether disease events are associated with endemic or recently introduced pathogens, and whether emerging strains are spreading throughout the region. In this study, we used a phylogenomic approach to address these questions of pathogen endemicity and spread for Erysipelothrix rhusiopathiae, an opportunistic multi-host bacterial pathogen associated with recent mortalities in arctic and boreal ungulate populations in North America. We isolated E. rhusiopathiae from carcasses associated with large-scale die-offs of muskoxen in the Canadian Arctic Archipelago, and from contemporaneous mortality events and/or population declines among muskoxen in northwestern Alaska and caribou and moose in western Canada. Bacterial genomic diversity differed markedly among these locations; minimal divergence was present among isolates from muskoxen in the Canadian Arctic, while in caribou and moose populations, strains from highly divergent clades were isolated from the same location, or even from within a single carcass. These results indicate that mortalities among northern ungulates are not associated with a single emerging strain of E. rhusiopathiae, and that alternate hypotheses need to be explored. Our study illustrates the value and limitations of bacterial genomic data for discriminating between ecological hypotheses of disease emergence, and highlights the importance of studying emerging pathogens within the broader context of environmental and host factors.

Shifts in disease dynamics in a tropical amphibian assemblage are not due to pathogen attenuation.

PubMed

Voyles, Jamie; Woodhams, Douglas C; Saenz, Veronica; Byrne, Allison Q; Perez, Rachel; Rios-Sotelo, Gabriela; Ryan, Mason J; Bletz, Molly C; Sobell, Florence Ann; McLetchie, Shawna; Reinert, Laura; Rosenblum, Erica Bree; Rollins-Smith, Louise A; Ibáñez, Roberto; Ray, Julie M; Griffith, Edgardo J; Ross, Heidi; Richards-Zawacki, Corinne L

2018-03-30

Infectious diseases rarely end in extinction. Yet the mechanisms that explain how epidemics subside are difficult to pinpoint. We investigated host-pathogen interactions after the emergence of a lethal fungal pathogen in a tropical amphibian assemblage. Some amphibian host species are recovering, but the pathogen is still present and is as pathogenic today as it was almost a decade ago. In addition, some species have defenses that are more effective now than they were before the epidemic. These results suggest that host recoveries are not caused by pathogen attenuation and may be due to shifts in host responses. Our findings provide insights into the mechanisms underlying disease transitions, which are increasingly important to understand in an era of emerging infectious diseases and unprecedented global pandemics. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Studying plant-pathogen interactions in the genomics era: beyond molecular Koch’s postulates to systems biology

USDA-ARS?s Scientific Manuscript database

Molecular factors enabling microbial pathogens to cause plant diseases have been sought with increasing efficacy over three research eras, which successively introduced the tools of disease physiology, single-gene molecular genetics, and genomics. From this work emerged a unified model of the intera...

Bacterial bloodstream infections in the allogeneic hematopoietic cell transplant patient: new considerations for a persistent nemesis.

PubMed

Dandoy, C E; Ardura, M I; Papanicolaou, G A; Auletta, J J

2017-08-01

Bacterial bloodstream infections (BSI) cause significant transplant-related morbidity and mortality following allogeneic hematopoietic cell transplantation (allo-HCT). This manuscript reviews the risk factors for and the bacterial pathogens causing BSIs in allo-HCT recipients in the contemporary transplant period. In addition, it offers insight into emerging resistant pathogens and reviews clinical management considerations to treat and strategies to prevent BSIs in allo-HCT patients.

Chlamydia Infection Across Host Species Boundaries Promotes Distinct Sets of Transcribed Anti-Apoptotic Factors

PubMed Central

Messinger, Joshua E.; Nelton, Emmalin; Feeney, Colleen; Gondek, David C.

2015-01-01

Chlamydiae, obligate intracellular bacteria, cause significant human and veterinary associated diseases. Having emerged an estimated 700-million years ago, these bacteria have twice adapted to humans as a host species, causing sexually transmitted infection (C. trachomatis) and respiratory associated disease (C. pneumoniae). The principle mechanism of host cell defense against these intracellular bacteria is the induction of cell death via apoptosis. However, in the “arms race” of co-evolution, Chlamydiae have developed mechanisms to promote cell viability and inhibit cell death. Herein we examine the impact of Chlamydiae infection across multiple host species on transcription of anti-apoptotic genes. We found mostly distinct patterns of gene expression (Mcl1 and cIAPs) elicited by each pathogen-host pair indicating Chlamydiae infection across host species boundaries does not induce a universally shared host response. Understanding species specific host-pathogen interactions is paramount to deciphering how potential pathogens become emerging diseases. PMID:26779446

Deciphering microbial landscapes of fish eggs to mitigate emerging diseases

PubMed Central

Liu, Yiying; de Bruijn, Irene; Jack, Allison LH; Drynan, Keith; van den Berg, Albert H; Thoen, Even; Sandoval-Sierra, Vladimir; Skaar, Ida; van West, Pieter; Diéguez-Uribeondo, Javier; van der Voort, Menno; Mendes, Rodrigo; Mazzola, Mark; Raaijmakers, Jos M

2014-01-01

Animals and plants are increasingly suffering from diseases caused by fungi and oomycetes. These emerging pathogens are now recognized as a global threat to biodiversity and food security. Among oomycetes, Saprolegnia species cause significant declines in fish and amphibian populations. Fish eggs have an immature adaptive immune system and depend on nonspecific innate defences to ward off pathogens. Here, meta-taxonomic analyses revealed that Atlantic salmon eggs are home to diverse fungal, oomycete and bacterial communities. Although virulent Saprolegnia isolates were found in all salmon egg samples, a low incidence of Saprolegniosis was strongly correlated with a high richness and abundance of specific commensal Actinobacteria, with the genus Frondihabitans (Microbacteriaceae) effectively inhibiting attachment of Saprolegniato salmon eggs. These results highlight that fundamental insights into microbial landscapes of fish eggs may provide new sustainable means to mitigate emerging diseases. PMID:24671087

Detecting the emergence of novel, zoonotic viruses pathogenic to humans.

PubMed

Rosenberg, Ronald

2015-03-01

RNA viruses, with their high potential for mutation and epidemic spread, are the most common class of pathogens found as new causes of human illness. Despite great advances made in diagnostic technology since the 1950s, the annual rate at which novel virulent viruses have been found has remained at 2-3. Most emerging viruses are zoonoses; they have jumped from mammal or bird hosts to humans. An analysis of virus discovery indicates that the small number of novel viruses discovered annually is an artifact of inadequate surveillance in tropical and subtropical countries, where even established endemic pathogens are often misdiagnosed. Many of the emerging viruses of the future are already infecting humans but remain to be uncovered by a strategy of disease surveillance in selected populations.

Novel organisms: comparing invasive species, GMOs, and emerging pathogens.

PubMed

Jeschke, Jonathan M; Keesing, Felicia; Ostfeld, Richard S

2013-09-01

Invasive species, range-expanding species, genetically modified organisms (GMOs), synthetic organisms, and emerging pathogens increasingly affect the human environment. We propose a framework that allows comparison of consecutive stages that such novel organisms go through. The framework provides a common terminology for novel organisms, facilitating knowledge exchange among researchers, managers, and policy makers that work on, or have to make effective decisions about, novel organisms. The framework also indicates that knowledge about the causes and consequences of stage transitions for the better studied novel organisms, such as invasive species, can be transferred to more poorly studied ones, such as GMOs and emerging pathogens. Finally, the framework advances understanding of how climate change can affect the establishment, spread, and impacts of novel organisms, and how biodiversity affects, and is affected by, novel organisms.

Zika Virus as an Emerging Global Pathogen

PubMed Central

Beckham, J. David; Pastula, Daniel M.; Massey, Aaron; Tyler, Kenneth L.

2016-01-01

IMPORTANCE Zika virus (ZIKV) is an emerging arthropod-borne virus (arbovirus) in the genus Flavivirus that has caused a widespread outbreak of febrile illness, is associated with neurological disease, and has spread across the Pacific to the Americas in a short period. OBSERVATIONS In this review, we discuss what is currently known about ZIKV, neuroimmunologic complications, and the impact on global human health. Zika virus spread across Africa and Asia in part owing to unique genomic evolutionary conditions and pressures resulting in specific human disease manifestations, complications, and pathogenesis. Recent data suggest that acute ZIKV infection in pregnant women may result in acute infection of fetal tissue and brain tissue, causing microcephaly and potentially severe debilitation of the infant or even death of the fetus. Cases of acute ZIKV are also associated with Guillain-Barré syndrome. With the increased number of cases, new complications such as ocular involvement and sexual transmission have been reported. CONCLUSIONS AND RELEVANCE Zika virus is an emerging viral pathogen with significant consequences on human health throughout the world. Ongoing research into this pathogen is urgently needed to produce viable vaccine and therapeutic options. PMID:27183312

Rapid Emergence of Highly Pathogenic Avian Influenza Subtypes from a Subtype H5N1 Hemagglutinin Variant.

PubMed

de Vries, Erik; Guo, Hongbo; Dai, Meiling; Rottier, Peter J M; van Kuppeveld, Frank J M; de Haan, Cornelis A M

2015-05-01

In 2014, novel highly pathogenic avian influenza A H5N2, H5N5, H5N6, and H5N8 viruses caused outbreaks in Asia, Europe, and North America. The H5 genes of these viruses form a monophyletic group that evolved from a clade 2.3.4 H5N1 variant. This rapid emergence of new H5Nx combinations is unprecedented in the H5N1 evolutionary history.

Enteroaggregative Escherichia coli: An Emerging Enteric Food Borne Pathogen

PubMed Central

Kaur, P.; Chakraborti, A.; Asea, A.

2010-01-01

Enteroaggregative Escherichia coli (EAEC) are quite heterogeneous category of an emerging enteric pathogen associated with cases of acute or persistent diarrhea worldwide in children and adults, and over the past decade has received increasing attention as a cause of watery diarrhea, which is often persistent. EAEC infection is an important cause of diarrhea in outbreak and non-outbreak settings in developing and developed countries. Recently, EAEC has been implicated in the development of irritable bowel syndrome, but this remains to be confirmed. EAEC is defined as a diarrheal pathogen based on its characteristic aggregative adherence (AA) to HEp-2 cells in culture and its biofilm formation on the intestinal mucosa with a “stacked-brick” adherence phenotype, which is related to the presence of a 60 MDa plasmid (pAA). At the molecular level, strains demonstrating the aggregative phenotype are quite heterogeneous; several virulence factors are detected by polymerase chain reaction; however, none exhibited 100% specificity. Although several studies have identified specific virulence factor(s) unique to EAEC, the mechanism by which EAEC exerts its pathogenesis is, thus, far unknown. The present review updates the current knowledge on the epidemiology, chronic complications, detection, virulence factors, and treatment of EAEC, an emerging enteric food borne pathogen. PMID:20300577

Vibrio Zinc-Metalloprotease Causes Photoinactivation of Coral Endosymbionts and Coral Tissue Lesions

PubMed Central

Sussman, Meir; Mieog, Jos C.; Doyle, Jason; Victor, Steven; Willis, Bette L.; Bourne, David G.

2009-01-01

Background Coral diseases are emerging as a serious threat to coral reefs worldwide. Of nine coral infectious diseases, whose pathogens have been characterized, six are caused by agents from the family Vibrionacae, raising questions as to their origin and role in coral disease aetiology. Methodology/Principal Findings Here we report on a Vibrio zinc-metalloprotease causing rapid photoinactivation of susceptible Symbiodinium endosymbionts followed by lesions in coral tissue. Symbiodinium photosystem II inactivation was diagnosed by an imaging pulse amplitude modulation fluorometer in two bioassays, performed by exposing Symbiodinium cells and coral juveniles to non-inhibited and EDTA-inhibited supernatants derived from coral white syndrome pathogens. Conclusion/Significance These findings demonstrate a common virulence factor from four phylogenetically related coral pathogens, suggesting that zinc-metalloproteases may play an important role in Vibrio pathogenicity in scleractinian corals. PMID:19225559

Disease ecology and the global emergence of zoonotic pathogens.

PubMed

Wilcox, Bruce A; Gubler, Duane J

2005-09-01

The incidence and frequency of epidemic transmission of zoonotic diseases, both known and newly recognized, has increased dramatically in the past 30 years. It is thought that this dramatic disease emergence is primarily the result of the social, demographic, and environmental transformation that has occurred globally since World War II. However, the causal linkages have not been elucidated. Investigating emerging zoonotic pathogens as an ecological phenomenon can provide significant insights as to why some of these pathogens have jumped species and caused major epidemics in humans. A review of concepts and theory from biological ecology and of causal factors in disease emergence previously described suggests a general model of global zoonotic disease emergence. The model links demographic and societal factors to land use and land cover change whose associated ecological factors help explain disease emergence. The scale and magnitude of these changes are more significant than those associated with climate change, the effects of which are largely not yet understood. Unfortunately, the complex character and non-linear behavior of the human-natural systems in which host-pathogen systems are embedded makes specific incidences of disease emergence or epidemics inherently difficult to predict. Employing a complex systems analytical approach, however, may show how a few key ecological variables and system properties, including the adaptive capacity of institutions, explains the emergence of infectious diseases and how an integrated, multi-level approach to zoonotic disease control can reduce risk.

Infection of Brachypodium distachyon by formae speciales of Puccinia graminis: early infection events and host-pathogen incompatibility

USDA-ARS?s Scientific Manuscript database

Brachypodium distachyon is an emerging model to study fungal disease resistance in cereals and grasses. We characterized the stem rust-Brachypodium pathosystem to evaluate its potential for investigating molecular and genetic aspects of resistance to P. graminis, the pathogen that causes stem rust. ...

The ecology of emerging infectious diseases in migratory birds: an assessment of the role of climate change and priorities for future research.

PubMed

Fuller, Trevon; Bensch, Staffan; Müller, Inge; Novembre, John; Pérez-Tris, Javier; Ricklefs, Robert E; Smith, Thomas B; Waldenström, Jonas

2012-03-01

Pathogens that are maintained by wild birds occasionally jump to human hosts, causing considerable loss of life and disruption to global commerce. Preliminary evidence suggests that climate change and human movements and commerce may have played a role in recent range expansions of avian pathogens. Since the magnitude of climate change in the coming decades is predicted to exceed climatic changes in the recent past, there is an urgent need to determine the extent to which climate change may drive the spread of disease by avian migrants. In this review, we recommend actions intended to mitigate the impact of emergent pathogens of migratory birds on biodiversity and public health. Increased surveillance that builds upon existing bird banding networks is required to conclusively establish a link between climate and avian pathogens and to prevent pathogens with migratory bird reservoirs from spilling over to humans.

Rational Design of Pathogen-Mimicking Amphiphilic Materials as Nanoadjuvants

NASA Astrophysics Data System (ADS)

Ulery, Bret D.; Petersen, Latrisha K.; Phanse, Yashdeep; Kong, Chang Sun; Broderick, Scott R.; Kumar, Devender; Ramer-Tait, Amanda E.; Carrillo-Conde, Brenda; Rajan, Krishna; Wannemuehler, Michael J.; Bellaire, Bryan H.; Metzger, Dennis W.; Narasimhan, Balaji

2011-12-01

An opportunity exists today for cross-cutting research utilizing advances in materials science, immunology, microbial pathogenesis, and computational analysis to effectively design the next generation of adjuvants and vaccines. This study integrates these advances into a bottom-up approach for the molecular design of nanoadjuvants capable of mimicking the immune response induced by a natural infection but without the toxic side effects. Biodegradable amphiphilic polyanhydrides possess the unique ability to mimic pathogens and pathogen associated molecular patterns with respect to persisting within and activating immune cells, respectively. The molecular properties responsible for the pathogen-mimicking abilities of these materials have been identified. The value of using polyanhydride nanovaccines was demonstrated by the induction of long-lived protection against a lethal challenge of Yersinia pestis following a single administration ten months earlier. This approach has the tantalizing potential to catalyze the development of next generation vaccines against diseases caused by emerging and re-emerging pathogens.

Experimental vaccines against potentially pandemic and highly pathogenic avian influenza viruses

PubMed Central

Mooney, Alaina J; Tompkins, S Mark

2013-01-01

Influenza A viruses continue to emerge and re-emerge, causing outbreaks, epidemics and occasionally pandemics. While the influenza vaccines licensed for public use are generally effective against seasonal influenza, issues arise with production, immunogenicity, and efficacy in the case of vaccines against pandemic and emerging influenza viruses, and highly pathogenic avian influenza virus in particular. Thus, there is need of improved influenza vaccines and vaccination strategies. This review discusses advances in alternative influenza vaccines, touching briefly on licensed vaccines and vaccine antigens; then reviewing recombinant subunit vaccines, virus-like particle vaccines and DNA vaccines, with the main focus on virus-vectored vaccine approaches. PMID:23440999

Tackling emerging fungal threats to animal health, food security and ecosystem resilience.

PubMed

Fisher, Matthew C; Gow, Neil A R; Gurr, Sarah J

2016-12-05

Emerging infections caused by fungi have become a widely recognized global phenomenon. Their notoriety stems from their causing plagues and famines, driving species extinctions, and the difficulty in treating human mycoses alongside the increase of their resistance to antifungal drugs. This special issue comprises a collection of articles resulting from a Royal Society discussion meeting examining why pathogenic fungi are causing more disease now than they did in the past, and how we can tackle this rapidly emerging threat to the health of plants and animals worldwide.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Author(s).

Disease-emergence dynamics and control in a socially-structured wildlife species

NASA Astrophysics Data System (ADS)

Pepin, Kim M.; Vercauteren, Kurt C.

2016-04-01

Once a pathogen is introduced in a population, key factors governing rate of spread include contact structure, supply of susceptible individuals and pathogen life-history. We examined the interplay of these factors on emergence dynamics and efficacy of disease prevention and response. We contrasted transmission dynamics of livestock viruses with different life-histories in hypothetical populations of feral swine with different contact structures (homogenous, metapopulation, spatial and network). Persistence probability was near 0 for the FMDV-like case under a wide range of parameter values and contact structures, while persistence was probable for the CSFV-like case. There were no sets of conditions where the FMDV-like pathogen persisted in every stochastic simulation. Even when population growth rates were up to 300% annually, the FMDV-like pathogen persisted in <25% of simulations regardless of transmission probabilities and contact structure. For networks and spatial contact structure, persistence probability of the FMDV-like pathogen was always <10%. Because of its low persistence probability, even very early response to the FMDV-like pathogen in feral swine was unwarranted while response to the CSFV-like pathogen was generally effective. When pre-emergence culling of feral swine caused population declines, it was effective at decreasing outbreak size of both diseases by ≥80%.

Decomposition and N cycling changes in redwood forests caused by sudden oak death

Treesearch

Richard C. Cobb; David M. Rizzo

2012-01-01

Phytophthora ramorum is an emergent pathogen in redwood forests which causes the disease sudden oak death. Although the disease does not kill coast redwood (Sequoia sempervirens), extensive and rapid mortality of tanoak (Notholithocarpus densiflorus) has removed this...

Severe soft tissue infection of the lower extremity caused by Haemophilus influenzae (serotype f, biotype II) in an adult patient.

PubMed

Hagiya, Hideharu; Murase, Tomoko; Naito, Hiromichi; Hagioka, Shingo; Morimoto, Naoki

2012-01-01

The infection caused by non-b-type Haemophilus influenzae has been increasing in this Hib (H.influenzae serotype b) vaccination era. H.influenzae serotype f (Hif) is considered as one of those emerging pathogens. In general, H.influenzae is a common pathogen of such as pneumonia, otitis media, and meningitis, but is rare in soft tissue infection, especially at the extremity. We report a rare case of severe soft tissue infection caused by Hif which occurred at the lower extremity of immunocompetent adult patient.

Cryptococcus gattii: where do we go from here?

PubMed

Harris, Julie; Lockhart, Shawn; Chiller, Tom

2012-02-01

Infections caused by the emerging pathogen Cryptococcus gattii are increasing in frequency in North America. During the past decade, interest in the pathogen has continued to grow, not only in North America but also in other areas of the world where infections have recently been documented. This review synthesizes existing data and raises issues that remain to be addressed.

An interspecific barberry hybrid enables genetic dissection of non-host resistance to the wheat stem rust pathogen

USDA-ARS?s Scientific Manuscript database

Stem rust, caused by the macrocyclic fungal pathogen Puccinia graminis (Pg), is one of the most devastating diseases of wheat and other small grains globally; and the emergence of new stem rust races virulent on deployed resistance genes brings urgency to the discovery of more durable sources of gen...

[Invasive fungal disease due to Scedosporium, Fusarium and mucorales].

PubMed

Pemán, Javier; Salavert, Miguel

2014-01-01

The number of emerging organisms causing invasive fungal infections has increased in the last decades. These etiological agents include Scedosporium, Fusarium and mucorales. All of them can cause disseminated, virulent, and difficult-to treat infections in immunosuppressed patients, the most affected, due to their resistance to most available antifungal agents. Current trends in transplantation including the use of new immunosuppressive treatments, the common prescription of antifungal agents for prophylaxis, and new ecological niches could explain the emergence of these fungal pathogens. These pathogens can also affect immunocompetent individuals, especially after natural disasters (earthquakes, floods, tsunamis), combat wounds or near drowning. All the invasive infections caused by Scedosporium, Fusarium, and mucorales are potentially lethal and a favourable outcome is associated with rapid diagnosis by direct microscopic examination of the involved tissue, wide debridement of infected material, early use of antifungal agents including combination therapy, and an improvement in host defenses, especially neutropenia. Copyright © 2014. Published by Elsevier Espana.

Host-pathogen interaction in Fusarium oxysporum infections: where do we stand?

PubMed

Husaini, Amjad M; Sakina, Aafreen; Cambay, Souliha R

2018-03-16

Fusarium oxysporum, a ubiquitous soil-borne pathogen causes devastating vascular wilt in more than 100 plant species and ranks fifth among top ten fungal plant pathogens. It has emerged as a human pathogen too, causing infections in immune-compromised patients. It is, therefore, important to gain insight into the molecular processes involved in the pathogenesis of this trans-kingdom pathogen. A complex network comprising of interconnected and over lapping signal pathways; mitogen-activated protein kinase (MAPK) signaling pathways, Ras proteins, G-protein signaling components and their downstream pathways, components of the velvet (LaeA/VeA/VelB) complex and cAMP pathways, is involved in perceiving the host. This network regulates the expression of various pathogenicity genes. Plants have however evolved an elaborate protection system to combat this attack. They too possess intricate mechanisms at molecular level, which once triggered by pathogen attack transduce signals to activate defense response. This review focuses on understanding and presenting a wholistic picture of the molecular mechanisms of F. oxysporum-host interactions in plant immunity.

Genetic analysis and antimicrobial susceptibility of Francisella noatunensis subsp. orientalis (sun. F. asiatica) isolates from fish

USDA-ARS?s Scientific Manuscript database

Francisella noatunensis subsp. orientalis (syn. F. asiatica) (Fno) is an emergent fish pathogen that causes acute to chronic disease in a wide variety of freshwater, brackish and marine fish. Due to the emergent nature of this bacterium, established protocols to measure antimicrobial susceptibility ...

The Emerging British Verticillium longisporum Population Consists of Aggressive Brassica Pathogens.

PubMed

Depotter, Jasper R L; Rodriguez-Moreno, Luis; Thomma, Bart P H J; Wood, Thomas A

2017-11-01

Verticillium longisporum is an economically important fungal pathogen of brassicaceous crops that originated from at least three hybridization events between different Verticillium spp., leading to the hybrid lineages A1/D1, A1/D2, and A1/D3. Isolates of lineage A1/D1 generally cause stem striping on oilseed rape (Brassica napus), which has recently been reported for the first time to occur in the United Kingdom. Intriguingly, the emerging U.K. population is distinct from the north-central European stem striping population. Little is known about the pathogenicity of the newly emerged U.K. population; hence, pathogenicity tests were executed to compare British isolates to previously characterized reference strains. In addition to the model plant Arabidopsis thaliana, the pathogenicity of four British isolates was assessed on four cultivars of three Brassica crop species: oilseed rape (Quartz and Incentive), cauliflower (Clapton), and Chinese cabbage (Hilton). To this end, vascular discoloration of the roots, plant biomass accumulations, and fungal stem colonization upon isolate infection were evaluated. The British isolates appeared to be remarkably aggressive, because plant biomass was significantly affected and severe vascular discoloration was observed. The British isolates were successful stem colonizers and the extent of fungal colonization negatively correlated with plant biomass of cauliflower and Quartz oilseed rape. However, in Quartz, the fungal colonization of A1/D1 isolates was significantly lower than that of the virulent reference isolate from lineage A1/D3, PD589. Moreover, despite levels of stem colonization similar to those of A1/D1 strains, PD589 did not cause significant disease on Incentive. Thus, A1/D1 isolates, including British isolates, are aggressive oilseed rape pathogens despite limited colonization levels in comparison with a virulent A1/D3 isolate.

Urban Breeding Corvids as Disseminators of Ticks and Emerging Tick-Borne Pathogens.

PubMed

Sándor, Attila D; Kalmár, Zsuzsa; Matei, Ioana; Ionică, Angela Monica; Mărcuţan, Ioan-Daniel

2017-02-01

Crows (Corvidae) are common city dwellers worldwide and are increasingly important subjects of epidemiology studies. Although their importance as hosts and transmitters of a number of zoonotic parasites and pathogens is well known, there are no studies on their importance as tick hosts. After mosquitoes, ticks are the most important vectors of zoonotic pathogens, especially for those causing emerging zoonotic diseases. Pathogenic bacteria, especially Borrelia spp., Rickettsia spp., and Anaplasma spp., vectored by ticks, are the cause for most vector-borne diseases in Europe. Here we report on ticks and tick-borne pathogens harbored by urban breeding crows. A total of 36 birds (33.33%, n = 108) hosted ticks, with 91 individual ticks belonging to 6 species (Haemaphysalis concinna, Haemaphysalis parva, Haemaphysalis punctata, Hyalomma marginatum, Ixodes arboricola, and Ixodes ricinus). Rickettsia spp. DNA was found in 6.6% of ticks and 1.9% of bird tissues, whereas Anaplasma phagocytophilum was found in 5.9% of ticks and 0.9% of birds. Two rickettsial genospecies were located, Rickettsia helvetica and Rickettsia monacensis. This is the first study to determine such a diverse tick spectrum feeding on urban corvids, while highlighting their importance as tick hosts and raising concerns about their potential risk to human health.

Future challenges in the elimination of bacterial meningitis.

PubMed

Bottomley, Matthew J; Serruto, Davide; Sáfadi, Marco Aurélio Palazzi; Klugman, Keith P

2012-05-30

Despite the widespread implementation of several effective vaccines over the past few decades, bacterial meningitis caused by Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis and Group B Streptococcus (GBS) still results in unacceptably high levels of human mortality and morbidity. A residual disease burden due to bacterial meningitis is also apparent due to a number of persistent or emerging pathogens, including Mycobacterium tuberculosis, Escherichia coli, Staphylococcus aureus, Salmonella spp. and Streptococcus suis. Here, we review the current status of bacterial meningitis caused by these pathogens, highlighting how past and present vaccination programs have attempted to counter these pathogens. We discuss how improved pathogen surveillance, implementation of current vaccines, and development of novel vaccines may be expected to further reduce bacterial meningitis and related diseases in the future. Copyright © 2011 Elsevier Ltd. All rights reserved.

Vacated niches, competitive release and the community ecology of pathogen eradication

PubMed Central

Lloyd-Smith, James O.

2013-01-01

A recurring theme in the epidemiological literature on disease eradication is that each pathogen occupies an ecological niche, and eradication of one pathogen leaves a vacant niche that favours the emergence of new pathogens to replace it. However, eminent figures have rejected this view unequivocally, stating that there is no basis to fear pathogen replacement and even that pathogen niches do not exist. After exploring the roots of this controversy, I propose resolutions to disputed issues by drawing on broader ecological theory, and advance a new consensus based on robust mechanistic principles. I argue that pathogen eradication (and cessation of vaccination) leads to a ‘vacated niche’, which could be re-invaded by the original pathogen if introduced. Consequences for other pathogens will vary, with the crucial mechanisms being competitive release, whereby the decline of one species allows its competitors to perform better, and evolutionary adaptation. Hence, eradication can cause a quantitative rise in the incidence of another infection, but whether this leads to emergence as an endemic pathogen depends on additional factors. I focus on the case study of human monkeypox and its rise following smallpox eradication, but also survey how these ideas apply to other pathogens and discuss implications for eradication policy. PMID:23798698

Disentangling host, pathogen, and environmental determinants of a recently emerged wildlife disease: lessons from the first 15 years of amphibian chytridiomycosis research.

PubMed

James, Timothy Y; Toledo, L Felipe; Rödder, Dennis; da Silva Leite, Domingos; Belasen, Anat M; Betancourt-Román, Clarisse M; Jenkinson, Thomas S; Soto-Azat, Claudio; Lambertini, Carolina; Longo, Ana V; Ruggeri, Joice; Collins, James P; Burrowes, Patricia A; Lips, Karen R; Zamudio, Kelly R; Longcore, Joyce E

2015-09-01

The amphibian fungal disease chytridiomycosis, which affects species across all continents, recently emerged as one of the greatest threats to biodiversity. Yet, many aspects of the basic biology and epidemiology of the pathogen, Batrachochytrium dendrobatidis (Bd), are still unknown, such as when and from where did Bd emerge and what is its true ecological niche? Here, we review the ecology and evolution of Bd in the Americas and highlight controversies that make this disease so enigmatic. We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment. Reevaluating the causes of the panzootic is timely given the wealth of data on Bd prevalence across hosts and communities and the recent discoveries suggesting co-evolutionary potential of hosts and Bd. We generate a new species distribution model for Bd in the Americas based on over 30,000 records and suggest a novel future research agenda. Instead of focusing on pathogen "hot spots," we need to identify pathogen "cold spots" so that we can better understand what limits the pathogen's distribution. Finally, we introduce the concept of "the Ghost of Epizootics Past" to discuss expected patterns in postepizootic host communities.

Highly Pathogenic Avian Influenza H5N6 Viruses Exhibit Enhanced Affinity for Human Type Sialic Acid Receptor and In-Contact Transmission in Model Ferrets

PubMed Central

Sun, Honglei; Pu, Juan; Wei, Yandi; Sun, Yipeng; Hu, Jiao; Liu, Litao; Xu, Guanlong; Gao, Weihua; Li, Chong; Zhang, Xuxiao; Huang, Yinhua; Chang, Kin-Chow; Liu, Xiufan

2016-01-01

ABSTRACT Since May 2014, highly pathogenic avian influenza H5N6 virus has been reported to cause six severe human infections three of which were fatal. The biological properties of this subtype, in particular its relative pathogenicity and transmissibility in mammals, are not known. We characterized the virus receptor-binding affinity, pathogenicity, and transmissibility in mice and ferrets of four H5N6 isolates derived from waterfowl in China from 2013-2014. All four H5N6 viruses have acquired a binding affinity for human-like SAα2,6Gal-linked receptor to be able to attach to human tracheal epithelial and alveolar cells. The emergent H5N6 viruses, which share high sequence similarity with the human isolate A/Guangzhou/39715/2014 (H5N6), were fully infective and highly transmissible by direct contact in ferrets but showed less-severe pathogenicity than the parental H5N1 virus. The present results highlight the threat of emergent H5N6 viruses to poultry and human health and the need to closely track their continual adaptation in humans. IMPORTANCE Extended epizootics and panzootics of H5N1 viruses have led to the emergence of the novel 2.3.4.4 clade of H5 virus subtypes, including H5N2, H5N6, and H5N8 reassortants. Avian H5N6 viruses from this clade have caused three fatalities out of six severe human infections in China since the first case in 2014. However, the biological properties of this subtype, especially the pathogenicity and transmission in mammals, are not known. Here, we found that natural avian H5N6 viruses have acquired a high affinity for human-type virus receptor. Compared to the parental clade 2.3.4 H5N1 virus, emergent H5N6 isolates showed less severe pathogenicity in mice and ferrets but acquired efficient in-contact transmission in ferrets. These findings suggest that the threat of avian H5N6 viruses to humans should not be ignored. PMID:27122581

Endocarditis caused by Rhodotorula infection.

PubMed

Simon, Matthew S; Somersan, Selin; Singh, Harjot K; Hartman, Barry; Wickes, Brian L; Jenkins, Stephen G; Walsh, Thomas J; Schuetz, Audrey N

2014-01-01

Rhodotorula is an emerging opportunistic fungal pathogen that is rarely reported to cause endocarditis. We describe a case involving a patient who developed endocarditis due to Rhodotorula mucilaginosa and Staphylococcus epidermidis, proven by culture and histopathology. The case illustrates the unique diagnostic and therapeutic challenges relevant to Rhodotorula spp.

Impact of Vector Dispersal and Host-Plant Fidelity on the Dissemination of an Emerging Plant Pathogen

PubMed Central

Johannesen, Jes; Foissac, Xavier; Kehrli, Patrik; Maixner, Michael

2012-01-01

Dissemination of vector-transmitted pathogens depend on the survival and dispersal of the vector and the vector's ability to transmit the pathogen, while the host range of vector and pathogen determine the breath of transmission possibilities. In this study, we address how the interaction between dispersal and plant fidelities of a pathogen (stolbur phytoplasma tuf-a) and its vector (Hyalesthes obsoletus: Cixiidae) affect the emergence of the pathogen. Using genetic markers, we analysed the geographic origin and range expansion of both organisms in Western Europe and, specifically, whether the pathogen's dissemination in the northern range is caused by resident vectors widening their host-plant use from field bindweed to stinging nettle, and subsequent host specialisation. We found evidence for common origins of pathogen and vector south of the European Alps. Genetic patterns in vector populations show signals of secondary range expansion in Western Europe leading to dissemination of tuf-a pathogens, which might be newly acquired and of hybrid origin. Hence, the emergence of stolbur tuf-a in the northern range was explained by secondary immigration of vectors carrying stinging nettle-specialised tuf-a, not by widening the host-plant spectrum of resident vectors with pathogen transmission from field bindweed to stinging nettle nor by primary co-migration from the resident vector's historical area of origin. The introduction of tuf-a to stinging nettle in the northern range was therefore independent of vector's host-plant specialisation but the rapid pathogen dissemination depended on the vector's host shift, whereas the general dissemination elsewhere was linked to plant specialisation of the pathogen but not of the vector. PMID:23284774

Impact of vector dispersal and host-plant fidelity on the dissemination of an emerging plant pathogen.

PubMed

Johannesen, Jes; Foissac, Xavier; Kehrli, Patrik; Maixner, Michael

2012-01-01

Dissemination of vector-transmitted pathogens depend on the survival and dispersal of the vector and the vector's ability to transmit the pathogen, while the host range of vector and pathogen determine the breath of transmission possibilities. In this study, we address how the interaction between dispersal and plant fidelities of a pathogen (stolbur phytoplasma tuf-a) and its vector (Hyalesthes obsoletus: Cixiidae) affect the emergence of the pathogen. Using genetic markers, we analysed the geographic origin and range expansion of both organisms in Western Europe and, specifically, whether the pathogen's dissemination in the northern range is caused by resident vectors widening their host-plant use from field bindweed to stinging nettle, and subsequent host specialisation. We found evidence for common origins of pathogen and vector south of the European Alps. Genetic patterns in vector populations show signals of secondary range expansion in Western Europe leading to dissemination of tuf-a pathogens, which might be newly acquired and of hybrid origin. Hence, the emergence of stolbur tuf-a in the northern range was explained by secondary immigration of vectors carrying stinging nettle-specialised tuf-a, not by widening the host-plant spectrum of resident vectors with pathogen transmission from field bindweed to stinging nettle nor by primary co-migration from the resident vector's historical area of origin. The introduction of tuf-a to stinging nettle in the northern range was therefore independent of vector's host-plant specialisation but the rapid pathogen dissemination depended on the vector's host shift, whereas the general dissemination elsewhere was linked to plant specialisation of the pathogen but not of the vector.

Fungal Contaminants in Drinking Water Regulation? A Tale of Ecology, Exposure, Purification and Clinical Relevance

PubMed Central

Novak Babič, Monika; Gunde-Cimerman, Nina; Vargha, Márta; Tischner, Zsófia; Magyar, Donát; Veríssimo, Cristina; Sabino, Raquel; Viegas, Carla; Meyer, Wieland; Brandão, João

2017-01-01

Microbiological drinking water safety is traditionally monitored mainly by bacterial parameters that indicate faecal contamination. These parameters correlate with gastro-intestinal illness, despite the fact that viral agents, resulting from faecal contamination, are usually the cause. This leaves behind microbes that can cause illness other than gastro-intestinal and several emerging pathogens, disregarding non-endemic microbial contaminants and those with recent pathogenic activity reported. This white paper focuses on one group of contaminants known to cause allergies, opportunistic infections and intoxications: Fungi. It presents a review on their occurrence, ecology and physiology. Additionally, factors contributing to their presence in water distribution systems, as well as their effect on water quality are discussed. Presence of opportunistic and pathogenic fungi in drinking water can pose a health risk to consumers due to daily contact with water, via several exposure points, such as drinking and showering. The clinical relevance and influence on human health of the most common fungal contaminants in drinking water is discussed. Our goal with this paper is to place fungal contaminants on the roadmap of evidence based and emerging threats for drinking water quality safety regulations.

A Novel Botrytis Species Is Associated with a Newly Emergent Foliar Disease in Cultivated Hemerocallis

PubMed Central

Grant-Downton, Robert T.; Terhem, Razak B.; Kapralov, Maxim V.; Mehdi, Saher; Rodriguez-Enriquez, M. Josefina; Gurr, Sarah J.; van Kan, Jan A. L.; Dewey, Frances M.

2014-01-01

Foliar tissue samples of cultivated daylilies (Hemerocallis hybrids) showing the symptoms of a newly emergent foliar disease known as ‘spring sickness’ were investigated for associated fungi. The cause(s) of this disease remain obscure. We isolated repeatedly a fungal species which proved to be member of the genus Botrytis, based on immunological tests. DNA sequence analysis of these isolates, using several different phyogenetically informative genes, indicated that they represent a new Botrytis species, most closely related to B. elliptica (lily blight, fire blight) which is a major pathogen of cultivated Lilium. The distinction of the isolates was confirmed by morphological analysis of asexual sporulating cultures. Pathogenicity tests on Hemerocallis tissues in vitro demonstrated that this new species was able to induce lesions and rapid tissue necrosis. Based on this data, we infer that this new species, described here as B. deweyae, is likely to be an important contributor to the development of ‘spring sickness’ symptoms. Pathogenesis may be promoted by developmental and environmental factors that favour assault by this necrotrophic pathogen. The emergence of this disease is suggested to have been triggered by breeding-related changes in cultivated hybrids, particularly the erosion of genetic diversity. Our investigation confirms that emergent plant diseases are important and deserve close monitoring, especially in intensively in-bred plants. PMID:24887415

Neoehrlichiosis: an emerging tick-borne zoonosis caused by Candidatus Neoehrlichia mikurensis.

PubMed

Silaghi, Cornelia; Beck, Relja; Oteo, José A; Pfeffer, Martin; Sprong, Hein

2016-03-01

Candidatus Neoehrlichia mikurensis is an emerging tick-borne pathogen causing a systemic inflammatory syndrome mostly in persons with underlying hematologic or autoimmune diseases. As it is neither well-known nor well-recognized, it might be misdiagnosed as recurrence of the underlying disease or as an unrelated arteriosclerotic vascular event. The pathogen is transmitted by hard ticks of the genus Ixodes and is closely associated with rodents in which transplacental transmission occurs. Transovarial transmission in ticks has not yet been shown. Infection rates vary greatly in ticks and rodents, but the causes for its spatiotemporal variations are largely unknown. This review summarizes the current state of knowledge on the geographical distribution and clinical importance of Ca. N. mikurensis. By elucidating the life history traits of this pathogen and determining more accurately its incidence in the human population, a better assessment of its public health relevance can be made. Most urgent research needs are the in vitro-cultivation of the pathogen, the development of specific serological tests, the determination of the full genomic sequence, the routine implementation of molecular diagnosis in diseased patients with a particular panel of underlying diseases, and promoting the knowledge about neoehrlichiosis among general practitioners, hospital physicians and the risk groups such as forest workers or immune-compromised people to raise awareness about this disease that can easily be treated when correctly diagnosed.

Amphibian decline and extinction: what we know and what we need to learn.

PubMed

Collins, James P

2010-11-01

For over 350 million yr, thousands of amphibian species have lived on Earth. Since the 1980s, amphibians have been disappearing at an alarming rate, in many cases quite suddenly. What is causing these declines and extinctions? In the modern era (post 1500) there are 6 leading causes of biodiversity loss in general, and all of these acting alone or together are responsible for modern amphibian declines: commercial use; introduced/exotic species that compete with, prey on, and parasitize native frogs and salamanders; land use change; contaminants; climate change; and infectious disease. The first 3 causes are historical in the sense that they have been operating for hundreds of years, although the rate of change due to each accelerated greatly after about the mid-20th century. Contaminants, climate change, and emerging infectious diseases are modern causes suspected of being responsible for the so-called 'enigmatic decline' of amphibians in protected areas. Introduced/exotic pathogens, land use change, and infectious disease are the 3 causes with a clear role in amphibian decline as well as extinction; thus far, the other 3 causes are only implicated in decline and not extinction. The present work is a review of the 6 causes with a focus on pathogens and suggested areas where new research is needed. Batrachochytrium dendrobatidis (Bd) is a chytrid fungus that is an emerging infectious disease causing amphibian population decline and species extinction. Historically, pathogens have not been seen as a major cause of extinction, but Bd is an exception, which is why it is such an interesting, important pathogen to understand. The late 20th and early 21st century global biodiversity loss is characterized as a sixth extinction event. Amphibians are a striking example of these losses as they disappear at a rate that greatly exceeds historical levels. Consequently, modern amphibian decline and extinction is a lens through which we can view the larger story of biodiversity loss and its consequences.

Actinobaculum schaalii, a new cause of knee prosthetic joint infection in elderly.

PubMed

Jacquier, H; Benmansour, H; Zadegan, F; Hannouche, D; Micaelo, M; Mongiat-Artus, P; Salomon, E; Cambau, E; Berçot, B

2016-08-01

Actinobaculum schaalii is an emerging pathogen particularly involved in urinary tract infection of elderly people and/or patient with urological risk factors of urinary tract infection. This microorganism is a difficult-to-diagnose pathogen and is rarely involved in systemic or deep infections. Here, we report the first case of prosthetic joint infection due to A. schaalii in an 84-year-old man with a benign prostatic hyperplasia associated with chronic retention of urine. This case underlines the importance to optimize the diagnosis of emerging uropathogens as A. schaalii, to prevent systemic infections, particularly in patients with orthopaedic implants.

Endocarditis Caused by Rhodotorula Infection

PubMed Central

Simon, Matthew S.; Somersan, Selin; Singh, Harjot K.; Hartman, Barry; Wickes, Brian L.; Jenkins, Stephen G.; Walsh, Thomas J.

2014-01-01

Rhodotorula is an emerging opportunistic fungal pathogen that is rarely reported to cause endocarditis. We describe a case involving a patient who developed endocarditis due to Rhodotorula mucilaginosa and Staphylococcus epidermidis, proven by culture and histopathology. The case illustrates the unique diagnostic and therapeutic challenges relevant to Rhodotorula spp. PMID:24197888

Exploitation of microbial forensics and nanotechnology for the monitoring of emerging pathogens.

PubMed

Bokhari, Habib

2018-03-07

Emerging infectious diseases remain among the leading causes of global mortality. Traditional laboratory diagnostic approaches designed to detect and track infectious disease agents provide a framework for surveillance of bio threats. However, surveillance and outbreak investigations using such time-consuming approaches for early detection of pathogens remain the major pitfall. Hence, reasonable real-time surveillance systems to anticipate threats to public health and environment are critical for identifying specific aetiologies and preventing the global spread of infectious disease. The current review discusses the growing need for monitoring and surveillance of pathogens with the same zeal and approach as adopted by microbial forensics laboratories, and further strengthening it by integrating with the innovative nanotechnology for rapid detection of microbial pathogens. Such innovative diagnostics platforms will help to track pathogens from high risk areas and environment by pre-emptive approach that will minimize damages. The various scenarios with the examples are discussed where the high risk associated human pathogens in particular were successfully detected using various nanotechnology approaches with potential future prospects in the field of microbial forensics.

Mechanisms of Antimicrobial Resistance in ESKAPE Pathogens

PubMed Central

Santajit, Sirijan; Indrawattana, Nitaya

2016-01-01

The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are the leading cause of nosocomial infections throughout the world. Most of them are multidrug resistant isolates, which is one of the greatest challenges in clinical practice. Multidrug resistance is amongst the top three threats to global public health and is usually caused by excessive drug usage or prescription, inappropriate use of antimicrobials, and substandard pharmaceuticals. Understanding the resistance mechanisms of these bacteria is crucial for the development of novel antimicrobial agents or other alternative tools to combat these public health challenges. Greater mechanistic understanding would also aid in the prediction of underlying or even unknown mechanisms of resistance, which could be applied to other emerging multidrug resistant pathogens. In this review, we summarize the known antimicrobial resistance mechanisms of ESKAPE pathogens. PMID:27274985

Mechanisms of Antimicrobial Resistance in ESKAPE Pathogens.

PubMed

Santajit, Sirijan; Indrawattana, Nitaya

2016-01-01

The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are the leading cause of nosocomial infections throughout the world. Most of them are multidrug resistant isolates, which is one of the greatest challenges in clinical practice. Multidrug resistance is amongst the top three threats to global public health and is usually caused by excessive drug usage or prescription, inappropriate use of antimicrobials, and substandard pharmaceuticals. Understanding the resistance mechanisms of these bacteria is crucial for the development of novel antimicrobial agents or other alternative tools to combat these public health challenges. Greater mechanistic understanding would also aid in the prediction of underlying or even unknown mechanisms of resistance, which could be applied to other emerging multidrug resistant pathogens. In this review, we summarize the known antimicrobial resistance mechanisms of ESKAPE pathogens.

Emerging zoonotic viral diseases.

PubMed

Wang, L-F; Crameri, G

2014-08-01

Zoonotic diseases are infectious diseases that are naturally transmitted from vertebrate animals to humans and vice versa. They are caused by all types of pathogenic agents, including bacteria, parasites, fungi, viruses and prions. Although they have been recognised for many centuries, their impact on public health has increased in the last few decades due to a combination of the success in reducing the spread of human infectious diseases through vaccination and effective therapies and the emergence of novel zoonotic diseases. It is being increasingly recognised that a One Health approach at the human-animal-ecosystem interface is needed for effective investigation, prevention and control of any emerging zoonotic disease. Here, the authors will review the drivers for emergence, highlight some of the high-impact emerging zoonotic diseases of the last two decades and provide examples of novel One Health approaches for disease investigation, prevention and control. Although this review focuses on emerging zoonotic viral diseases, the authors consider that the discussions presented in this paper will be equally applicable to emerging zoonotic diseases of other pathogen types.

Ventilator-associated pneumonia caused by ESKAPE organisms: cause, clinical features, and management.

PubMed

Sandiumenge, Alberto; Rello, Jordi

2012-05-01

Despite important geographical variations, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species (ESKAPE) pathogens constitute more than 80% of ventilator-associated pneumonia (VAP) episodes. Their clinical importance relies on their virulence and ability in developing mechanisms to decrease susceptibility to antimicrobials, increasing inappropriate therapy and affecting negatively on ICU patients' outcome. This review updates information on VAP due to ESKAPE pathogens. Although methicillin-resistant Staphylococcus aureus VAP may be clinically similar to that caused by susceptible strains, it is associated with poorer outcomes despite adequate treatment. Local colonization determines treatment options. The contribution of tracheobronchitis is an important issue. Minimum inhibitory concentration should be considered for nonfermentative Gram-negative bacteria VAP to prescribe extended infusion β-lactam treatment due to an increase of resistant strains. Strategies promoting antimicrobial diversity may protect against emergence and spread of resistance by ESKAPE pathogens. VAP due to ESKAPE pathogens represents a global challenge that can be prevented using stewardship programmes promoting diversity.

The Vietnam Initiative on Zoonotic Infections (VIZIONS): A Strategic Approach to Studying Emerging Zoonotic Infectious Diseases.

PubMed

Rabaa, Maia A; Tue, Ngo Tri; Phuc, Tran My; Carrique-Mas, Juan; Saylors, Karen; Cotten, Matthew; Bryant, Juliet E; Nghia, Ho Dang Trung; Cuong, Nguyen Van; Pham, Hong Anh; Berto, Alessandra; Phat, Voong Vinh; Dung, Tran Thi Ngoc; Bao, Long Hoang; Hoa, Ngo Thi; Wertheim, Heiman; Nadjm, Behzad; Monagin, Corina; van Doorn, H Rogier; Rahman, Motiur; Tra, My Phan Vu; Campbell, James I; Boni, Maciej F; Tam, Pham Thi Thanh; van der Hoek, Lia; Simmonds, Peter; Rambaut, Andrew; Toan, Tran Khanh; Van Vinh Chau, Nguyen; Hien, Tran Tinh; Wolfe, Nathan; Farrar, Jeremy J; Thwaites, Guy; Kellam, Paul; Woolhouse, Mark E J; Baker, Stephen

2015-12-01

The effect of newly emerging or re-emerging infectious diseases of zoonotic origin in human populations can be potentially catastrophic, and large-scale investigations of such diseases are highly challenging. The monitoring of emergence events is subject to ascertainment bias, whether at the level of species discovery, emerging disease events, or disease outbreaks in human populations. Disease surveillance is generally performed post hoc, driven by a response to recent events and by the availability of detection and identification technologies. Additionally, the inventory of pathogens that exist in mammalian and other reservoirs is incomplete, and identifying those with the potential to cause disease in humans is rarely possible in advance. A major step in understanding the burden and diversity of zoonotic infections, the local behavioral and demographic risks of infection, and the risk of emergence of these pathogens in human populations is to establish surveillance networks in populations that maintain regular contact with diverse animal populations, and to simultaneously characterize pathogen diversity in human and animal populations. Vietnam has been an epicenter of disease emergence over the last decade, and practices at the human/animal interface may facilitate the likelihood of spillover of zoonotic pathogens into humans. To tackle the scientific issues surrounding the origins and emergence of zoonotic infections in Vietnam, we have established The Vietnam Initiative on Zoonotic Infections (VIZIONS). This countrywide project, in which several international institutions collaborate with Vietnamese organizations, is combining clinical data, epidemiology, high-throughput sequencing, and social sciences to address relevant one-health questions. Here, we describe the primary aims of the project, the infrastructure established to address our scientific questions, and the current status of the project. Our principal objective is to develop an integrated approach to the surveillance of pathogens circulating in both human and animal populations and assess how frequently they are exchanged. This infrastructure will facilitate systematic investigations of pathogen ecology and evolution, enhance understanding of viral cross-species transmission events, and identify relevant risk factors and drivers of zoonotic disease emergence.

Neglected and emerging fungal infections: review of hyalohyphomycosis by Paecilomyces lilacinus focusing in disease burden, in vitro antifungal susceptibility and management.

PubMed

Antas, Paulo R Z; Brito, Marcelly M S; Peixoto, Érika; Ponte, Carlos G G; Borba, Cíntia M

2012-01-01

Paecilomyces lilacinus is an emerging pathogenic fungus that can cause different clinical manifestations ranging from cutaneous and sub-cutaneous infections to severe oculomycosis. This review discusses infections caused by P. lilacinus, as well as their symptoms and correlates of immune responses, morphological characteristics of the fungus, therapies, in vitro susceptibility tests, laboratory diagnosis and the experimental models available. Copyright © 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Recent introduction of a chytrid fungus endangers Western Palearctic salamanders

PubMed Central

Martel, A.; Beukema, W.; Fisher, M. C.; Farrer, R. A.; Schmidt, B. R.; Tobler, U.; Goka, K.; Lips, K. R.; Muletz, C.; Zamudio, K. R.; Bosch, J.; Lötters, S.; Wombwell, E.; Garner, T.W. J.; Cunningham, A. A.; Spitzen-van der Sluijs, A.; Salvidio, S.; Ducatelle, R.; Nishikawa, K.; Nguyen, T. T.; Kolby, J. E.; Van Bocxlaer, I.; Bossuyt, F.; Pasmans, F.

2018-01-01

Emerging infectious diseases are reducing biodiversity on a global scale. Recently, the emergence of the chytrid fungus Batrachochytrium salamandrivorans resulted in rapid declines in populations of European fire salamanders. Here, we screened more than 5000 amphibians from across four continents and combined experimental assessment of pathogenicity with phylogenetic methods to estimate the threat that this infection poses to amphibian diversity. Results show that B. salamandrivorans is restricted to, but highly pathogenic for, salamanders and newts (Urodela). The pathogen likely originated and remained in coexistence with a clade of salamander hosts for millions of years in Asia. As a result of globalization and lack of biosecurity, it has recently been introduced into naïve European amphibian populations, where it is currently causing biodiversity loss. PMID:25359973

A molecular arms race between host innate antiviral response and emerging human coronaviruses.

PubMed

Wong, Lok-Yin Roy; Lui, Pak-Yin; Jin, Dong-Yan

2016-02-01

Coronaviruses have been closely related with mankind for thousands of years. Community-acquired human coronaviruses have long been recognized to cause common cold. However, zoonotic coronaviruses are now becoming more a global concern with the discovery of highly pathogenic severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronaviruses causing severe respiratory diseases. Infections by these emerging human coronaviruses are characterized by less robust interferon production. Treatment of patients with recombinant interferon regimen promises beneficial outcomes, suggesting that compromised interferon expression might contribute at least partially to the severity of disease. The mechanisms by which coronaviruses evade host innate antiviral response are under intense investigations. This review focuses on the fierce arms race between host innate antiviral immunity and emerging human coronaviruses. Particularly, the host pathogen recognition receptors and the signal transduction pathways to mount an effective antiviral response against SARS and MERS coronavirus infection are discussed. On the other hand, the counter-measures evolved by SARS and MERS coronaviruses to circumvent host defense are also dissected. With a better understanding of the dynamic interaction between host and coronaviruses, it is hoped that insights on the pathogenesis of newly-identified highly pathogenic human coronaviruses and new strategies in antiviral development can be derived.

Risks Posed by Reston, the Forgotten Ebolavirus

PubMed Central

Cantoni, Diego; Hamlet, Arran; Michaelis, Martin; Wass, Mark N.

2016-01-01

ABSTRACT Out of the five members of the Ebolavirus family, four cause life-threatening disease, whereas the fifth, Reston virus (RESTV), is nonpathogenic in humans. The reasons for this discrepancy remain unclear. In this review, we analyze the currently available information to provide a state-of-the-art summary of the factors that determine the human pathogenicity of Ebolaviruses. RESTV causes sporadic infections in cynomolgus monkeys and is found in domestic pigs throughout the Philippines and China. Phylogenetic analyses revealed that RESTV is most closely related to the Sudan virus, which causes a high mortality rate in humans. Amino acid sequence differences between RESTV and the other Ebolaviruses are found in all nine Ebolavirus proteins, though no one residue appears sufficient to confer pathogenicity. Changes in the glycoprotein contribute to differences in Ebolavirus pathogenicity but are not sufficient to confer pathogenicity on their own. Similarly, differences in VP24 and VP35 affect viral immune evasion and are associated with changes in human pathogenicity. A recent in silico analysis systematically determined the functional consequences of sequence variations between RESTV and human-pathogenic Ebolaviruses. Multiple positions in VP24 were differently conserved between RESTV and the other Ebolaviruses and may alter human pathogenicity. In conclusion, the factors that determine the pathogenicity of Ebolaviruses in humans remain insufficiently understood. An improved understanding of these pathogenicity-determining factors is of crucial importance for disease prevention and for the early detection of emergent and potentially human-pathogenic RESTVs. PMID:28066813

Searching for animal models and potential target species for emerging pathogens: Experience gained from Middle East respiratory syndrome (MERS) coronavirus.

PubMed

Vergara-Alert, Júlia; Vidal, Enric; Bensaid, Albert; Segalés, Joaquim

2017-06-01

Emerging and re-emerging pathogens represent a substantial threat to public health, as demonstrated with numerous outbreaks over the past years, including the 2013-2016 outbreak of Ebola virus in western Africa. Coronaviruses are also a threat for humans, as evidenced in 2002/2003 with infection by the severe acute respiratory syndrome coronavirus (SARS-CoV), which caused more than 8000 human infections with 10% fatality rate in 37 countries. Ten years later, a novel human coronavirus (Middle East respiratory syndrome coronavirus, MERS-CoV), associated with severe pneumonia, arose in the Kingdom of Saudi Arabia. Until December 2016, MERS has accounted for more than 1800 cases and 35% fatality rate. Finding an animal model of disease is key to develop vaccines or antivirals against such emerging pathogens and to understand its pathogenesis. Knowledge of the potential role of domestic livestock and other animal species in the transmission of pathogens is of importance to understand the epidemiology of the disease. Little is known about MERS-CoV animal host range. In this paper, experimental data on potential hosts for MERS-CoV is reviewed. Advantages and limitations of different animal models are evaluated in relation to viral pathogenesis and transmission studies. Finally, the relevance of potential new target species is discussed.

Update on host-pathogen interactions in cystic fibrosis lung disease.

PubMed

Hector, Andreas; Frey, Nina; Hartl, Dominik

2016-12-01

Bacterial and fungal infections are hallmarks of cystic fibrosis (CF) lung disease. In the era of long-term inhaled antibiotics and increasing CF patient survival, new "emerging" pathogens are detected in CF airways, yet their pathophysiological disease relevance remains largely controversial and incompletely defined. As a response to chronic microbial triggers, innate immune cells, particularly neutrophils, are continuously recruited into CF airways where they combat pathogens but also cause tissue injury through release of oxidants and proteases. The coordinated interplay between host immune cell activation and pathogens is essential for the outcome of CF lung disease. Here, we provide a concise overview and update on host-pathogen interactions in CF lung disease.

Rice Sheath Rot: An Emerging Ubiquitous Destructive Disease Complex

PubMed Central

Bigirimana, Vincent de P.; Hua, Gia K. H.; Nyamangyoku, Obedi I.; Höfte, Monica

2015-01-01

Around one century ago, a rice disease characterized mainly by rotting of sheaths was reported in Taiwan. The causal agent was identified as Acrocylindrium oryzae, later known as Sarocladium oryzae. Since then it has become clear that various other organisms can cause similar disease symptoms, including Fusarium sp. and fluorescent pseudomonads. These organisms have in common that they produce a range of phytotoxins that induce necrosis in plants. The same agents also cause grain discoloration, chaffiness, and sterility and are all seed-transmitted. Rice sheath rot disease symptoms are found in all rice-growing areas of the world. The disease is now getting momentum and is considered as an important emerging rice production threat. The disease can lead to variable yield losses, which can be as high as 85%. This review aims at improving our understanding of the disease etiology of rice sheath rot and mainly deals with the three most reported rice sheath rot pathogens: S. oryzae, the Fusarium fujikuroi complex, and Pseudomonas fuscovaginae. Causal agents, pathogenicity determinants, interactions among the various pathogens, epidemiology, geographical distribution, and control options will be discussed. PMID:26697031

Genetic mechanisms of multidrug resistance among Klebsiella pneumoniae isolates from food-producing animals and humans in Lagos, Nigeria

USDA-ARS?s Scientific Manuscript database

Klebsiella pneumoniae is an opportunistic pathogen that commonly causes hospital and community acquired bacterial infections in humans. The emergence and rapid spread of multi- drug resistant (MDR) K. pneumoniae is causing drug therapy failure amid patients leading to poor antibiotic management glob...

The expanding spectrum of human infections caused by Kocuria species: a case report and literature review

PubMed Central

Purty, Shashikala; Saranathan, Rajagopalan; Prashanth, K; Narayanan, K; Asir, Johny; Sheela Devi, Chandrakesan; Kumar Amarnath, Satish

2013-01-01

Although not previously known to cause human infections, Kocuria species have now emerged as human pathogens, mostly in compromised hosts with severe underlying disease. Recently, there has been an increasing incidence of different types of Kocuria infections reported, most likely due to the adoption of better identification methods. Here, we report a case of peritonitis caused by Kocuria rosea in a diabetic nephropathy patient who was on continuous ambulatory peritoneal dialysis. Sepsis and peritonitis caused by K. rosea in our case yielded two identical Kocuria isolates from the peritoneal dialysate fluid within a period of three days. The infection was subsequently resolved by antibiotic treatment and catheter removal. In addition to reporting this case, we herein review the literature concerning the emergence of Kocuria as a significant human pathogen. The majority of cases were device-related, acquired in the hospital or endogenous, and different Kocuria species appear to share a common etiology of peritonitis. The overall disease burden associated with Kocuria appears to be high, and the treatment guidelines for diseases associated with Kocuria have not yet been clearly defined. PMID:26038440

A Review of the Current Status of Relevant Zoonotic Pathogens in Wild Swine (Sus scrofa) Populations: Changes Modulating the Risk of Transmission to Humans.

PubMed

Ruiz-Fons, F

2017-02-01

Many wild swine populations in different parts of the World have experienced an unprecedented demographic explosion that may result in increased exposure of humans to wild swine zoonotic pathogens. Interactions between humans and wild swine leading to pathogen transmission could come from different ways, being hunters and game professionals the most exposed to acquiring infections from wild swine. However, increasing human settlements in semi-natural areas, outdoor activities, socio-economic changes and food habits may increase the rate of exposure to wild swine zoonotic pathogens and to potentially emerging pathogens from wild swine. Frequent and increasing contact rate between humans and wild swine points to an increasing chance of zoonotic pathogens arising from wild swine to be transmitted to humans. Whether this frequent contact could lead to new zoonotic pathogens emerging from wild swine to cause human epidemics or emerging disease outbreaks is difficult to predict, and assessment should be based on thorough epidemiologic surveillance. Additionally, several gaps in knowledge on wild swine global population dynamics trends and wild swine-zoonotic pathogen interactions should be addressed to correctly assess the potential role of wild swine in the emergence of diseases in humans. In this work, viruses such as hepatitis E virus, Japanese encephalitis virus, Influenza virus and Nipah virus, and bacteria such as Salmonella spp., Shiga toxin-producing Escherichia coli, Campylobacter spp. and Leptospira spp. have been identified as the most prone to be transmitted from wild swine to humans on the basis of geographic spread in wild swine populations worldwide, pathogen circulation rates in wild swine populations, wild swine population trends in endemic areas, susceptibility of humans to infection, transmissibility from wild swine to humans and existing evidence of wild swine-human transmission events. © 2015 Blackwell Verlag GmbH.

LAMP detection assays for boxwood blight pathogens: A comparative genomics approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malapi-Wight, Martha; Demers, Jill E.; Veltri, Daniel

Rapid and accurate molecular diagnostic tools are critical to efforts to minimize the impact and spread of emergent pathogens. The identification of diagnostic markers for novel pathogens presents several challenges, especially in the absence of information about population diversity and where genetic resources are limited. The objective of this study was to use comparative genomics datasets to find unique target regions suitable for the diagnosis of two fungal species causing a newly emergent blight disease of boxwood. Candidate marker regions for loop-mediated isothermal amplification (LAMP) assays were identified from draft genomes of Calonectria henricotiae and C. pseudonaviculata, as well asmore » three related species not associated with this disease. To increase the probability of identifying unique targets, we used three approaches to mine genome datasets, based on (i) unique regions, (ii) polymorphisms, and (iii) presence/absence of regions across datasets. From a pool of candidate markers, we demonstrate LAMP assay specificity by testing related fungal species, common boxwood pathogens, and environmental samples containing 445 diverse fungal taxa. In conclusion, this comparative-genomics-based approach to the development of LAMP diagnostic assays is the first of its kind for fungi and could be easily applied to diagnostic marker development for other newly emergent plant pathogens.« less

LAMP detection assays for boxwood blight pathogens: A comparative genomics approach

DOE PAGES

Malapi-Wight, Martha; Demers, Jill E.; Veltri, Daniel; ...

2016-05-20

Rapid and accurate molecular diagnostic tools are critical to efforts to minimize the impact and spread of emergent pathogens. The identification of diagnostic markers for novel pathogens presents several challenges, especially in the absence of information about population diversity and where genetic resources are limited. The objective of this study was to use comparative genomics datasets to find unique target regions suitable for the diagnosis of two fungal species causing a newly emergent blight disease of boxwood. Candidate marker regions for loop-mediated isothermal amplification (LAMP) assays were identified from draft genomes of Calonectria henricotiae and C. pseudonaviculata, as well asmore » three related species not associated with this disease. To increase the probability of identifying unique targets, we used three approaches to mine genome datasets, based on (i) unique regions, (ii) polymorphisms, and (iii) presence/absence of regions across datasets. From a pool of candidate markers, we demonstrate LAMP assay specificity by testing related fungal species, common boxwood pathogens, and environmental samples containing 445 diverse fungal taxa. In conclusion, this comparative-genomics-based approach to the development of LAMP diagnostic assays is the first of its kind for fungi and could be easily applied to diagnostic marker development for other newly emergent plant pathogens.« less

Emerging Viral Infections in Pakistan: Issues, Concerns, and Future Prospects.

PubMed

Khalil, Ali Talha; Ali, Muhammad; Tanveer, Faouzia; Ovais, Muhammad; Idrees, Muhammad; Shinwari, Zabta Khan; Hollenbeck, James E

Emerging infectious diseases pose a serious threat to public health security; this is especially true in the underdeveloped world because of limited resources to combat them. These emerging pathogens are characterized by a novel mode of pathogenesis and, in some cases, a broad host range. Over the past few decades, Pakistan has suffered a great deal from infectious diseases such as dengue, Crimean-Congo fever, hepatitis, measles, and polio. Changing climate conditions, environmental degradation, global warming, loss of biodiversity, and other ecological determinants have a direct effect on these diseases and result in the emergence and reemergence of infectious entities. The causes of such disease outbreaks are complex and often not well understood. Dealing with an outbreak requires an integrated and coordinated approach, with decision making by various state departments. Stringent biosecurity and biosafety protocols can help to reduce the chances of infection dissemination. In order to mitigate the risks associated with emerging pathogens, there is a greater need to understand the interactions of pathogen-host-environment, to monitor molecular evolution and genomic surveillance, and to facilitate the gearing up of scientists across the globe to control these emerging diseases. This article reviews recent outbreaks in Pakistan and challenges for the development of an agile healthcare setup in the country.

One Health, emerging infectious diseases and wildlife: two decades of progress?

PubMed

Cunningham, Andrew A; Daszak, Peter; Wood, James L N

2017-07-19

Infectious diseases affect people, domestic animals and wildlife alike, with many pathogens being able to infect multiple species. Fifty years ago, following the wide-scale manufacture and use of antibiotics and vaccines, it seemed that the battle against infections was being won for the human population. Since then, however, and in addition to increasing antimicrobial resistance among bacterial pathogens, there has been an increase in the emergence of, mostly viral, zoonotic diseases from wildlife, sometimes causing fatal outbreaks of epidemic proportions. Concurrently, infectious disease has been identified as an increasing threat to wildlife conservation. A synthesis published in 2000 showed common anthropogenic drivers of disease threats to biodiversity and human health, including encroachment and destruction of wildlife habitat and the human-assisted spread of pathogens. Almost two decades later, the situation has not changed and, despite improved knowledge of the underlying causes, little has been done at the policy level to address these threats. For the sake of public health and wellbeing, human-kind needs to work better to conserve nature and preserve the ecosystem services, including disease regulation, that biodiversity provides while also understanding and mitigating activities which lead to disease emergence. We consider that holistic, One Health approaches to the management and mitigation of the risks of emerging infectious diseases have the greatest chance of success.This article is part of the themed issue 'One Health for a changing world: zoonoses, ecosystems and human well-being'. © 2017 The Authors.

Evolutionary aspects of emerging Lyme disease in Canada.

PubMed

Ogden, N H; Feil, E J; Leighton, P A; Lindsay, L R; Margos, G; Mechai, S; Michel, P; Moriarty, T J

2015-11-01

In North America, Lyme disease (LD) is a tick-borne zoonosis caused by the spirochete bacterium Borrelia burgdorferi sensu stricto, which is maintained by wildlife. Tick vectors and bacteria are currently spreading into Canada and causing increasing numbers of cases of LD in humans and raising a pressing need for public health responses. There is no vaccine, and LD prevention depends on knowing who is at risk and informing them how to protect themselves from infection. Recently, it was found in the United States that some strains of B. burgdorferi sensu stricto cause severe disease, whereas others cause mild, self-limiting disease. While many strains occurring in the United States also occur in Canada, strains in some parts of Canada are different from those in the United States. We therefore recognize a need to identify which strains specific to Canada can cause severe disease and to characterize their geographic distribution to determine which Canadians are particularly at risk. In this review, we summarize the history of emergence of LD in North America, our current knowledge of B. burgdorferi sensu stricto diversity, its intriguing origins in the ecology and evolution of the bacterium, and its importance for the epidemiology and clinical and laboratory diagnosis of LD. We propose methods for investigating associations between B. burgdorferi sensu stricto diversity, ecology, and pathogenicity and for developing predictive tools to guide public health interventions. We also highlight the emergence of B. burgdorferi sensu stricto in Canada as a unique opportunity for exploring the evolutionary aspects of tick-borne pathogen emergence. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Emerging pharmacologic therapies for primary sclerosing cholangitis.

PubMed

Cheung, Angela C; Lazaridis, Konstantinos N; LaRusso, Nicholas F; Gores, Gregory J

2017-05-01

The only currently approved treatment for primary sclerosing cholangitis (PSC) is liver transplantation, with a median time to transplant of 12-18 years after diagnosis. There are a number of emerging drugs that have the potential to meet this critically unmet need that will be summarized and discussed herein. Although the cause of PSC is unknown, there are a number of novel therapeutics under development. These drugs target presumed pathogenic mechanisms largely extrapolated from ex-vivo and in-vivo preclinical models, as well as translational observations. Future therapeutic strategies for PSC may include a multitude of complex pathogenic mechanisms encompassing pathways of immunomodulation, the microbiome and inflammation-related fibrosis.

Protection of White Leghorn chickens by U.S. emergency H5 vaccines against clade 2.3.4.4 H5N2 high pathogenicity avian influenza virus

USDA-ARS?s Scientific Manuscript database

During December 2014-June 2015, the U.S. experienced a high pathogenicity avian influenza (HPAI) outbreak caused by clade 2.3.4.4 H5Nx Goose/Guangdong lineage viruses which was the worst HPAI event for the poultry industry. Three vaccines, developed based on updating existing registered vaccines or ...

Evaluation of Three Vaccine Technologies to Protect White leghorn Chickens from H5N2 clade 2.3.4.4 Gs/GD High Pathogenicity Avian Influenza

USDA-ARS?s Scientific Manuscript database

During December 2014-June 2015, the USA experienced a high pathogenicity avian influenza (HPAI) outbreak caused by clade 2.3.4.4 H5Nx Goose/Guangdong lineage viruses which was the worst HPAI event for the USA’s poultry industries. Three emergency vaccines, based on updating existing registered vacc...

Streptococcus suis infection

PubMed Central

Feng, Youjun; Zhang, Huimin; Wu, Zuowei; Wang, Shihua; Cao, Min; Hu, Dan; Wang, Changjun

2014-01-01

Streptococcus suis (S. suis) is a family of pathogenic gram-positive bacterial strains that represents a primary health problem in the swine industry worldwide. S. suis is also an emerging zoonotic pathogen that causes severe human infections clinically featuring with varied diseases/syndromes (such as meningitis, septicemia, and arthritis). Over the past few decades, continued efforts have made significant progress toward better understanding this zoonotic infectious entity, contributing in part to the elucidation of the molecular mechanism underlying its high pathogenicity. This review is aimed at presenting an updated overview of this pathogen from the perspective of molecular epidemiology, clinical diagnosis and typing, virulence mechanism, and protective antigens contributing to its zoonosis. PMID:24667807

DEVELOPMENT OF A MOLECULAR METHOD TO IDENTIFY ...

EPA Pesticide Factsheets

Hepatitis E virus (HEV) is an emerging pathogen that causes significant illness in the developing world. Like the hepatitis A virus, it is transmitted via the fecal-oral route and can cause short-term, acute hepatitis. In addition, hepatitis E has been found to cause a significant rate of mortality in pregnant women. Thus far, a hepatitis E outbreak has not been reported in the U. S. although a swine variant of the virus is common in Midwestern hogs. Since it will be important to identify the presence of this virus in the water supply, we have developed and are testing a reverse transcription-polymerase chain reaction (RT-PCR) method that should be able to identify all of the known HEV strains. Develop sensitive techniques to detect and identify emerging human waterborne pathogenic viruses and viruses on the CCL.Determine effectiveness of viral indicators to measure microbial quality in water matrices.Support activities: (a) culture and distribution of mammalian cells for Agency and scientific community research needs, (b) provide operator expertise for research requiring confocal and electron microscopy, (c) glassware cleaning, sterilization and biological waste disposal for the Cincinnati EPA facility, (d) operation of infectious pathogenic suite, (e) maintenance of walk-in constant temperature rooms and (f) provide Giardia cysts.

Coxsackievirus A6: a new emerging pathogen causing hand, foot and mouth disease outbreaks worldwide.

PubMed

Bian, Lianlian; Wang, Yiping; Yao, Xin; Mao, Qunying; Xu, Miao; Liang, Zhenglun

2015-01-01

Enterovirus 71 (EV71) and coxsackievirus A16 (CA16) are the predominant pathogens causing outbreaks of hand, foot and mouth disease (HFMD) worldwide. Other human enterovirus A (HEV-A) serotypes tend to cause only sporadic HFMD cases. However, since a HFMD caused by coxsackievirus A6 broke out in Finland in 2008, CA6 has been identified as the responsible pathogen for a series of HFMD outbreaks in Europe, North America and Asia. Because of the severity of the clinical manifestations and the underestimated public health burden, the epidemic of CA6-associated HFMD presents a new challenge to the control of HFMD. This article reviewed the epidemic characteristics, molecular epidemiology, clinical features and laboratory diagnosis of CA6 infection. The genetic evolution of CA6 strains associated with HFMD was also analyzed. It indicated that the development of a multivalent vaccine combining EV71, CA16 and CA6 is an urgent necessity to control HFMD.

Predicting the spread of sudden oak death in California: spatial-temporal modeling of susceptible-infectious transitions

Treesearch

Richard D. Hunter; Ross K. Meentemeyer; David M. Rizzo; Christopher A. Gilligan

2008-01-01

The number of emerging infectious diseases is thought to be increasing worldwide - many of which are caused by non-native, invasive plant pathogens I n forest ecosystems. As new diseases continue to emerge, the ability to predict disease outbreaks is critical for effective management and prevention of epidemics, especially in complex spatially heterogeneous landscapes...

Silver nanoparticles: synthesis, properties, toxicology, applications and perspectives

NASA Astrophysics Data System (ADS)

Tran, Quang Huy; Quy Nguyen, Van; Le, Anh-Tuan

2013-09-01

In recent years the outbreak of re-emerging and emerging infectious diseases has been a significant burden on global economies and public health. The growth of population and urbanization along with poor water supply and environmental hygiene are the main reasons for the increase in outbreak of infectious pathogens. Transmission of infectious pathogens to the community has caused outbreaks of diseases such as influenza (A/H5N1), diarrhea (Escherichia coli), cholera (Vibrio cholera), etc throughout the world. The comprehensive treatments of environments containing infectious pathogens using advanced disinfectant nanomaterials have been proposed for prevention of the outbreaks. Among these nanomaterials, silver nanoparticles (Ag-NPs) with unique properties of high antimicrobial activity have attracted much interest from scientists and technologists to develop nanosilver-based disinfectant products. This article aims to review the synthesis routes and antimicrobial effects of Ag-NPs against various pathogens including bacteria, fungi and virus. Toxicology considerations of Ag-NPs to humans and ecology are discussed in detail. Some current applications of Ag-NPs in water-, air- and surface- disinfection are described. Finally, future prospects of Ag-NPs for treatment and prevention of currently emerging infections are discussed.

Particulate delivery systems for vaccination against bioterrorism agents and emerging infectious pathogens

PubMed Central

Fan, Yuchen; Moon, James J.

2016-01-01

Bioterrorism agents that can be easily transmitted with high mortality rates and cause debilitating diseases pose major threats to national security and public health. The recent Ebola virus outbreak in West Africa and ongoing Zika virus outbreak in Brazil, now spreading throughout Latin America, are case examples of emerging infectious pathogens that have incited widespread fear and economic and social disruption on a global scale. Prophylactic vaccines would provide effective countermeasures against infectious pathogens and biological warfare agents. However, traditional approaches relying on attenuated or inactivated vaccines have been hampered by their unacceptable levels of reactogenicity and safety issues, whereas subunit antigen-based vaccines suffer from suboptimal immunogenicity and efficacy. In contrast, particulate vaccine delivery systems offer key advantages, including efficient and stable delivery of subunit antigens, co-delivery of adjuvant molecules to bolster immune responses, low reactogenicity due to the use of biocompatible biomaterials, and robust efficiency to elicit humoral and cellular immunity in systemic and mucosal tissues. Thus, vaccine nanoparticles and microparticles are promising platforms for clinical development of biodefense vaccines. In this review, we summarize the current status of research efforts to develop particulate vaccine delivery systems against bioterrorism agents and emerging infectious pathogens. PMID:27038091

The emerging diversity of Rickettsia

PubMed Central

Perlman, Steve J; Hunter, Martha S; Zchori-Fein, Einat

2006-01-01

The best-known members of the bacterial genus Rickettsia are associates of blood-feeding arthropods that are pathogenic when transmitted to vertebrates. These species include the agents of acute human disease such as typhus and Rocky Mountain spotted fever. However, many other Rickettsia have been uncovered in recent surveys of bacteria associated with arthropods and other invertebrates; the hosts of these bacteria have no relationship with vertebrates. It is therefore perhaps more appropriate to consider Rickettsia as symbionts that are transmitted vertically in invertebrates, and secondarily as pathogens of vertebrates. In this review, we highlight the emerging diversity of Rickettsia species that are not associated with vertebrate pathogenicity. Phylogenetic analysis suggests multiple transitions between symbionts that are transmitted strictly vertically and those that exhibit mixed (horizontal and vertical) transmission. Rickettsia may thus be an excellent model system in which to study the evolution of transmission pathways. We also focus on the emergence of Rickettsia as a diverse reproductive manipulator of arthropods, similar to the closely related Wolbachia, including strains associated with male-killing, parthenogenesis, and effects on fertility. We emphasize some outstanding questions and potential research directions, and suggest ways in which the study of non-pathogenic Rickettsia can advance our understanding of their disease-causing relatives. PMID:16901827

Highly Pathogenic Avian Influenza H5N6 Viruses Exhibit Enhanced Affinity for Human Type Sialic Acid Receptor and In-Contact Transmission in Model Ferrets.

PubMed

Sun, Honglei; Pu, Juan; Wei, Yandi; Sun, Yipeng; Hu, Jiao; Liu, Litao; Xu, Guanlong; Gao, Weihua; Li, Chong; Zhang, Xuxiao; Huang, Yinhua; Chang, Kin-Chow; Liu, Xiufan; Liu, Jinhua

2016-07-15

Since May 2014, highly pathogenic avian influenza H5N6 virus has been reported to cause six severe human infections three of which were fatal. The biological properties of this subtype, in particular its relative pathogenicity and transmissibility in mammals, are not known. We characterized the virus receptor-binding affinity, pathogenicity, and transmissibility in mice and ferrets of four H5N6 isolates derived from waterfowl in China from 2013-2014. All four H5N6 viruses have acquired a binding affinity for human-like SAα2,6Gal-linked receptor to be able to attach to human tracheal epithelial and alveolar cells. The emergent H5N6 viruses, which share high sequence similarity with the human isolate A/Guangzhou/39715/2014 (H5N6), were fully infective and highly transmissible by direct contact in ferrets but showed less-severe pathogenicity than the parental H5N1 virus. The present results highlight the threat of emergent H5N6 viruses to poultry and human health and the need to closely track their continual adaptation in humans. Extended epizootics and panzootics of H5N1 viruses have led to the emergence of the novel 2.3.4.4 clade of H5 virus subtypes, including H5N2, H5N6, and H5N8 reassortants. Avian H5N6 viruses from this clade have caused three fatalities out of six severe human infections in China since the first case in 2014. However, the biological properties of this subtype, especially the pathogenicity and transmission in mammals, are not known. Here, we found that natural avian H5N6 viruses have acquired a high affinity for human-type virus receptor. Compared to the parental clade 2.3.4 H5N1 virus, emergent H5N6 isolates showed less severe pathogenicity in mice and ferrets but acquired efficient in-contact transmission in ferrets. These findings suggest that the threat of avian H5N6 viruses to humans should not be ignored. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Itraconazole-resistant Candida auris with phospholipase, proteinase and hemolysin activity from a case of vulvovaginitis.

PubMed

Kumar, Dharmendra; Banerjee, Tuhina; Pratap, Chandra Bhan; Tilak, Ragini

2015-04-15

Since the emergence of pathogenic non-albicans Candida species, a number of new isolates have been added to the list. One such unusual species is Candida auris (C. auris), recently isolated and studied in few reports. In this study, a case of vulvovaginitis caused by Candida auris incidentally identified by molecular methods using internal transcribed spacer polymerase chain reaction (ITS PCR) is described. Antifungal susceptibility testing revealed the isolate to be resistant to itraconazole (MIC ≥ 2 µg/ml) and expressed important virulence factors including phospholipase, proteinase and hemolysin activity. The patient was successfully treated with oral fluconazole and did not have any invasive fungemia. Very few cases of this emerging pathogen have been reported. However, its isolation from clinical specimens reveals the significance of non-albicans candida species over C. albicans and the diversity of Candida spp causing infections.

[Environmental drivers of emergence and spreading of Vibrio epidemics in South America].

PubMed

Gavilán, Ronnie G; Martínez-Urtaza, Jaime

2011-03-01

Vibrio cholerae and V. parahaemolyticus are the two Vibrio species with a major impact on human health. Diseases caused by both pathogens are acquiring increasing relevance due to their expansion at global scale. In this paper, we resume the ecological aspects associated with the arrival and spreading of infections caused by V. parahaemolyticus and V. cholerae in Peru from a South American perspective. Moreover, we discuss the similarities in the emergence in Peru of cholera cases in 1991 and V. parahaemolyticus infections in 1997. These constituted exceptional experiments to evaluate the relationships between the Vibrio epidemics and changes in the environment. The epidemic radiations of V. cholerae and V. parahaemolyticus constitute to clear examples supporting the oceanic dispersion of pathogenic vibrios and have enabled the identification of El Niño events as a potential mechanism for the spreading of diseases through the ocean.

Duck "beak atrophy and dwarfism syndrome" disease complex: Interplay of novel goose parvovirus-related virus and duck circovirus?

PubMed

Li, P; Li, J; Zhang, R; Chen, J; Wang, W; Lan, J; Xie, Z; Jiang, S

2018-04-01

As a newly emerged infectious disease, duck "beak atrophy and dwarfism syndrome (BADS)" disease has caused huge economic losses to waterfowl industry in China since 2015. Novel goose parvovirus-related virus (NGPV) is believed the main pathogen of BADS disease; however, BADS is rarely reproduced by infecting ducks with NGPV alone. As avian circovirus infection causes clinical symptoms similar to BADS, duck circovirus (DuCV) is suspected the minor pathogen of BADS disease. In this study, an investigation was carried out to determine the coinfection of NGPV and DuCV in duck embryos and in ducks with BADS disease. According to our study, the coinfection of emerging NGPV and DuCV was prevalent in East China (Shandong, Jiangsu and Anhui province) and could be vertical transmitted, indicating their cooperative roles in duck BADS disease. © 2018 Blackwell Verlag GmbH.

Dermatological infectiology--Quo vadis? Symposium, Ruhr-University, September 29-30, 2000. Abstracts.

PubMed

2000-11-30

Infectious diseases remain a major cause of morbidity and mortality in the year 2000. 17 million deaths per year or roughly a third of all deaths are caused by infections. Infectious diseases also pose a serious economic threat. While many well-established pathogens have not been contained several new infectious agents have been discovered within the past 27 years which include rotavirus, legionella, HIV, ebola, campylobacter, helicobacter, nipah, HHV8, hepatitis C, and many others. Additionally many new pathogens have emerged as serious threats to the ever-growing number of immuno-compromised patients. Infectious etiologies have been found for many common diseases (certain leukemias, duodenal ulcers, etcetera). It is likely that infections are at least co-factors for many other diseases (transplant-associated atherosclerosis). Only specialized care and multi-disciplinary collaboration will enable us to cope with current problems and the inevitable emergence of new infectious diseases.

A multi-scale conceptual model of fire and disease interactions in North American forests

NASA Astrophysics Data System (ADS)

Varner, J. M.; Kreye, J. K.; Sherriff, R.; Metz, M.

2013-12-01

One aspect of global change with increasing attention is the interactions between irruptive pests and diseases and wildland fire behavior and effects. These pests and diseases affect fire behavior and effects in spatially and temporally complex ways. Models of fire and pathogen interactions have been constructed for individual pests or diseases, but to date, no synthesis of this complexity has been attempted. Here we synthesize North American fire-pathogen interactions into syndromes with similarities in spatial extent and temporal duration. We base our models on fire interactions with three examples: sudden oak death (caused by the pathogen Phytopthora ramorum) and the native tree tanoak (Notholithocarpus densiflorus); mountain pine beetle (Dendroctonus ponderosae) and western Pinus spp.; and hemlock woolly adelgid (Adelges tsugae) on Tsuga spp. We evaluate each across spatial (severity of attack from branch to landscape scale) and temporal scales (from attack to decades after) and link each change to its coincident effects on fuels and potential fire behavior. These syndromes differ in their spatial and temporal severity, differentially affecting windows of increased or decreased community flammability. We evaluate these models with two examples: the recently emergent ambrosia beetle-vectored laurel wilt (caused by the pathogen Raffaelea lauricola) in native members of the Lauraceae and the early 20th century chestnut blight (caused by the pathogen Cryphonectria parasitica) that led to the decline of American chestnut (Castanea dentata). Some changes (e.g., reduced foliar moisture content) have short-term consequences for potential fire behavior while others (functional extirpation) have more complex indirect effects on community flammability. As non-native emergent diseases and pests continue, synthetic models that aid in prediction of fire behavior and effects will enable the research and management community to prioritize mitigation efforts to realized effects.

Phlebotomine sand fly–borne pathogens in the Mediterranean Basin: Human leishmaniasis and phlebovirus infections

PubMed Central

Moriconi, Martina; Rugna, Gianluca; Calzolari, Mattia; Bellini, Romeo; Albieri, Alessandro; Angelini, Paola; Cagarelli, Roberto; Landini, Maria P.

2017-01-01

Pathogens transmitted to humans by phlebotomine sand flies are neglected, as they cause infectious diseases that are not on the priority list of national and international public health systems. However, the infections caused by protozoa of the Leishmania genus and viruses belonging to the Phlebovirus genus (family Phenuiviridae)—the most significant group of viruses transmitted by sand flies—have a relevant role for human pathology. These infections are emerging in the Mediterranean region and will likely spread in forthcoming decades, posing a complex threat to human health. Four species and 2 hybrid strains of Leishmania are pathogenic for humans in the Mediterranean Basin, with an estimated annual incidence of 239,500–393,600 cases of cutaneous leishmaniasis and 1,200–2,000 cases of visceral leishmaniasis. Among the phleboviruses, Toscana virus can cause neuroinvasive infections, while other phleboviruses are responsible for a typical “3-day fever”; the actual incidence of Phlebovirus infections in the Mediterranean area is unknown, although at least 250 million people are exposed. Here, we reviewed the current literature on epidemiology of sand fly–borne infections in the Mediterranean Basin, with a focus on humans. Our analysis indicates the need for increased public health activities directed to determine the disease burden of these infections as well as to improve their surveillance. Among the emerging challenges concerning sand fly–borne pathogens, the relationships between sand fly–borne protozoa and viruses should be considered in future studies, including epidemiological links between Leishmania and phleboviruses as well as the conditional capacity for these pathogens to be involved in interactions that may evolve towards increased virulence. PMID:28796786

Conservation implications of physiological carry-over effects in bats recovering from white-nose syndrome.

PubMed

Davy, Christina M; Mastromonaco, Gabriela F; Riley, Julia L; Baxter-Gilbert, James H; Mayberry, Heather; Willis, Craig K R

2017-06-01

Although it is well documented that infectious diseases can pose threats to biodiversity, the potential long-term consequences of pathogen exposure on individual fitness and its effects on population viability have rarely been studied. We tested the hypothesis that pathogen exposure causes physiological carry-over effects with a pathogen that is uniquely suited to this question because the infection period is specific and time limited. The fungus Pseudogymnoascus destructans causes white-nose syndrome (WNS) in hibernating bats, which either die due to the infection while hibernating or recover following emergence from hibernation. The fungus infects all exposed individuals in an overwintering site simultaneously, and bats that survive infection during hibernation clear the pathogen within a few weeks following emergence. We quantified chronic stress during the active season, when bats are not infected, by measuring cortisol in bat claws. Free-ranging Myotis lucifugus who survived previous exposure to P. destructans had significantly higher levels of claw cortisol than naïve individuals. Thus, cryptic physiological carry-over effects of pathogen exposure may persist in asymptomatic, recovered individuals. If these effects result in reduced survival or reproductive success, they could also affect population viability and even act as a third stream in the extinction vortex. For example, significant increases in chronic stress, such as those indicated here, are correlated with reduced reproductive success in a number of species. Future research should directly explore the link between pathogen exposure and the viability of apparently recovered populations to improve understanding of the true impacts of infectious diseases on threatened populations. © 2016 Society for Conservation Biology.

Wide but variable distribution of a hypervirulent Campylobacter jejuni clone in beef and dairy cattle in the united states

USDA-ARS?s Scientific Manuscript database

Campylobacter jejuni is a significant concern for ruminant health and food safety. Recently, a highly pathogenic C. jejuni clone (named SA) has emerged as the predominant cause of ruminant abortion and a significant cause of foodborne illnesses in the United States. Despite the recent advance in und...

New monoclonal antibodies against a novel subtype of Shiga toxin 1 produced by Enterobacter cloacae and their use in analysis of human serum

USDA-ARS?s Scientific Manuscript database

Shiga toxin (Stx) is a major virulence factor for several bacterial pathogens that cause potentially fatal illness, including Escherichia coli and Shigella spp. The continual emergence of new subtypes of Stxs presents challenges in clinical diagnosis of infections caused by Shiga toxin-producing org...

Evolution of pathogenicity traits in the apple scab fungal pathogen in response to the domestication of its host

PubMed Central

Lê Van, Amandine; Gladieux, Pierre; Lemaire, Christophe; Cornille, Amandine; Giraud, Tatiana; Durel, Charles-Eric; Caffier, Valérie; Le Cam, Bruno

2012-01-01

Understanding how pathogens emerge is essential to bring disease-causing agents under durable human control. Here, we used cross-pathogenicity tests to investigate the changes in life-history traits of the fungal pathogen Venturia inaequalis associated with host-tracking during the domestication of apple and subsequent host-range expansion on the wild European crabapple (Malus sylvestris). Pathogenicity of 40 isolates collected in wild and domesticated ecosystems was assessed on the domesticated apple, its Central Asian main progenitor (M. sieversii) and M. sylvestris. Isolates from wild habitats in the centre of origin of the crop were not pathogenic on the domesticated apple and less aggressive than other isolates on their host of origin. Isolates from the agro-ecosystem in Central Asia infected a higher proportion of plants with higher aggressiveness, on both the domesticated host and its progenitor. Isolates from the European crabapple were still able to cause disease on other species but were less aggressive and less frequently virulent on these hosts than their endemic populations. Our results suggest that the domestication of apple was associated with the acquisition of virulence in the pathogen following host-tracking. The spread of the disease in the agro-ecosystem would also have been accompanied by an increase in overall pathogenicity. PMID:23144656

Parallel Evolution of Two Clades of an Atlantic-Endemic Pathogenic Lineage of Vibrio parahaemolyticus by Independent Acquisition of Related Pathogenicity Islands

PubMed Central

Xu, Feng; Drees, Kevin P.; Sebra, Robert P.; Jones, Stephen H.

2017-01-01

ABSTRACT Shellfish-transmitted Vibrio parahaemolyticus infections have recently increased from locations with historically low disease incidence, such as the Northeast United States. This change coincided with a bacterial population shift toward human-pathogenic variants occurring in part through the introduction of several Pacific native lineages (ST36, ST43, and ST636) to nearshore areas off the Atlantic coast of the Northeast United States. Concomitantly, ST631 emerged as a major endemic pathogen. Phylogenetic trees of clinical and environmental isolates indicated that two clades diverged from a common ST631 ancestor, and in each of these clades, a human-pathogenic variant evolved independently through acquisition of distinct Vibrio pathogenicity islands (VPaI). These VPaI differ from each other and bear little resemblance to hemolysin-containing VPaI from isolates of the pandemic clonal complex. Clade I ST631 isolates either harbored no hemolysins or contained a chromosome I-inserted island we call VPaIβ that encodes a type 3 secretion system (T3SS2β) typical of Trh hemolysin producers. The more clinically prevalent and clonal ST631 clade II had an island we call VPaIγ that encodes both tdh and trh and that was inserted in chromosome II. VPaIγ was derived from VPaIβ but with some additional acquired elements in common with VPaI carried by pandemic isolates, exemplifying the mosaic nature of pathogenicity islands. Genomics comparisons and amplicon assays identified VPaIγ-type islands containing tdh inserted adjacent to the ure cluster in the three introduced Pacific and most other emergent lineages that collectively cause 67% of infections in the Northeast United States as of 2016. IMPORTANCE The availability of three different hemolysin genotypes in the ST631 lineage provided a unique opportunity to employ genome comparisons to further our understanding of the processes underlying pathogen evolution. The fact that two different pathogenic clades arose in parallel from the same potentially benign lineage by independent VPaI acquisition is surprising considering the historically low prevalence of community members harboring VPaI in waters along the Northeast U.S. coast that could serve as the source of this material. This illustrates a possible predisposition of some lineages to not only acquire foreign DNA but also become human pathogens. Whereas the underlying cause for the expansion of V. parahaemolyticus lineages harboring VPaIγ along the U.S. Atlantic coast and spread of this element to multiple lineages that underlies disease emergence is not known, this work underscores the need to define the environment factors that favor bacteria harboring VPaI in locations of emergent disease. PMID:28687650

Characteristics of human infection with avian influenza viruses and development of new antiviral agents

PubMed Central

Liu, Qiang; Liu, Dong-ying; Yang, Zhan-qiu

2013-01-01

Since 1997, several epizootic avian influenza viruses (AIVs) have been transmitted to humans, causing diseases and even deaths. The recent emergence of severe human infections with AIV (H7N9) in China has raised concerns about efficient interpersonal viral transmission, polygenic traits in viral pathogenicity and the management of newly emerging strains. The symptoms associated with viral infection are different in various AI strains: H5N1 and newly emerged H7N9 induce severe pneumonia and related complications in patients, while some H7 and H9 subtypes cause only conjunctivitis or mild respiratory symptoms. The virulence and tissue tropism of viruses as well as the host responses contribute to the pathogenesis of human AIV infection. Several preventive and therapeutic approaches have been proposed to combat AIV infection, including antiviral drugs such as M2 inhibitors, neuraminidase inhibitors, RNA polymerase inhibitors, attachment inhibitors and signal-transduction inhibitors etc. In this article, we summarize the recent progress in researches on the epidemiology, clinical features, pathogenicity determinants, and available or potential antivirals of AIV. PMID:24096642

Developing Research in Infectious and Tropical Diseases in Africa: The Paradigm of Senegal.

PubMed

Sokhna, Cheikh; Gaye, Oumar; Doumbo, Ogobara

2017-08-15

Infectious diseases represent one of the greatest potential barriers to achievement of the third Sustainable Development Goals in African countries and around the world because they continue to pose major public health challenges. The surveillance of infectious diseases has recently assumed greater importance in most African countries, both because of the emergence of infectious diseases and because strains of pathogens that cause tuberculosis, malaria, cholera, dysentery, and pneumonia have developed resistance to common and inexpensive antimicrobial drugs. However, data on the pathogen-specific causes of infectious diseases are limited. Developing research in infectious and tropical diseases in Africa is urgently needed to better describe the distribution of pathogen-borne diseases and to know which pathogens actually cause fever. This research is critical for guiding treatment and policies in Africa. More effective diagnostics are also needed for these diseases, which often are misdiagnosed or diagnosed too late. A comprehensive review of this type of research is presented here. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

STREPTOCOCCUS: A WORLDWIDE FISH HEALTH PROBLEM

USDA-ARS?s Scientific Manuscript database

Streptococcus iniae and S. agalactiae are important emergent pathogens that affect many fish species worldwide, especially in warm-water regions. In marine and freshwater systems, these Gram-positive bacteria cause significant economic losses, estimated at hundreds of millions of dollars annually. ...

Prediction of Pan-Specific B-Cell Epitopes From Nucleocapsid Protein of Hantaviruses Causing Hantavirus Cardiopulmonary Syndrome.

PubMed

Kalaiselvan, Sagadevan; Sankar, Sathish; Ramamurthy, Mageshbabu; Ghosh, Asit Ranjan; Nandagopal, Balaji; Sridharan, Gopalan

2017-08-01

Hantaviruses are emerging viral pathogens that causes hantavirus cardiopulmonary syndrome (HCPS) in the Americas, a severe, sometimes fatal, respiratory disease in humans with a case fatality rate of ≥50%. IgM and IgG-based serological detection methods are the most common approaches used for laboratory diagnosis of hantaviruses. Such emerging viral pathogens emphasizes the need for improved rapid diagnostic devices and vaccines incorporating pan-specific epitopes of genotypes. We predicted linear B-cell epitopes for hantaviruses that are specific to genotypes causing HCPS in humans using in silico prediction servers. We modeled the Andes and Sin Nombre hantavirus nucleocapsid protein to locate the identified epitopes. Based on the mean percent prediction probability score, epitope IMASKSVGS/TAEEKLKKKSAF was identified as the best candidate B-cell epitope specific for hantaviruses causing HCPS. Promiscuous epitopes were identified in the C-terminal of the protein. Our study for the first time has reported pan-specific B-cell epitopes for developing immunoassays in the detection of antibodies to hantaviruses causing HCPS. Identification of epitopes with pan-specific recognition of all genotypes causing HCPS could be valuable for the development of immunodiagnositic tools toward pan-detection of hantavirus antibodies in ELISA. J. Cell. Biochem. 118: 2320-2324, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Occurrence of infected amoebae in cooling towers compared with natural aquatic environments: implications for emerging pathogens.

PubMed

Berk, S G; Gunderson, J H; Newsome, A L; Farone, A L; Hayes, B J; Redding, K S; Uddin, N; Williams, E L; Johnson, R A; Farsian, M; Reid, A; Skimmyhorn, J; Farone, M B

2006-12-01

Many species of bacteria pathogenic to humans, such as Legionella, are thought to have evolved in association with amoebal hosts. Several novel unculturable bacteria related to Legionella have also been found in amoebae, a few of which have been thought to be causes of nosocomial infections in humans. Because amoebae can be found in cooling towers, we wanted to know whether cooling tower environments might enhance the association between amoebae and bacterial pathogens of amoebae in order to identify potential "hot spots" for emerging human pathogens. To compare occurrence of infected amoebae in natural environments with those in cooling towers, 40 natural aquatic environments and 40 cooling tower samples were examined. Logistic regression analysis determined variables that were significant predictors of the occurrence of infected amoebae, which were found in 22 of 40 cooling tower samples but in only 3 of the 40 natural samples. An odds ratio showed that it is over 16 times more likely to encounter infected amoebae in cooling towers than in natural environments. Environmental data from cooling towers and natural habitats combined revealed dissolved organic carbon (DOC) and pH were predictors of the occurrence of the pathogens, however, when cooling tower data alone were analyzed, no variables accounted for the occurrence. Several bacteria have novel rRNA sequences, and most strains were not culturable outside of amoebae. Such pathogens of amoebae may spread to the environment via aerosols from cooling towers. Studies of emerging infectious diseases should strongly consider cooling towers as a source of amoeba-associated pathogens.

Genome-wide phylogenetic analysis of the pathogenic potential of Vibrio furnissii

PubMed Central

Lux, Thomas M.; Lee, Rob; Love, John

2014-01-01

We recently reported the genome sequence of a free-living strain of Vibrio furnissii (NCTC 11218) harvested from an estuarine environment. V. furnissii is a widespread, free-living proteobacterium and emerging pathogen that can cause acute gastroenteritis in humans and lethal zoonoses in aquatic invertebrates, including farmed crustaceans and molluscs. Here we present the analyses to assess the potential pathogenic impact of V. furnissii. We compared the complete genome of V. furnissii with 8 other emerging and pathogenic Vibrio species. We selected and analyzed more deeply 10 genomic regions based upon unique or common features, and used 3 of these regions to construct a phylogenetic tree. Thus, we positioned V. furnissii more accurately than before and revealed a closer relationship between V. furnissii and V. cholerae than previously thought. However, V. furnissii lacks several important features normally associated with virulence in the human pathogens V. cholera and V. vulnificus. A striking feature of the V. furnissii genome is the hugely increased Super Integron, compared to the other Vibrio. Analyses of predicted genomic islands resulted in the discovery of a protein sequence that is present only in Vibrio associated with diseases in aquatic animals. We also discovered evidence of high levels horizontal gene transfer in V. furnissii. V. furnissii seems therefore to have a dynamic and fluid genome that could quickly adapt to environmental perturbation or increase its pathogenicity. Taken together, these analyses confirm the potential of V. furnissii as an emerging marine and possible human pathogen, especially in the developing, tropical, coastal regions that are most at risk from climate change. PMID:25191313

Genome-wide phylogenetic analysis of the pathogenic potential of Vibrio furnissii.

PubMed

Lux, Thomas M; Lee, Rob; Love, John

2014-01-01

We recently reported the genome sequence of a free-living strain of Vibrio furnissii (NCTC 11218) harvested from an estuarine environment. V. furnissii is a widespread, free-living proteobacterium and emerging pathogen that can cause acute gastroenteritis in humans and lethal zoonoses in aquatic invertebrates, including farmed crustaceans and molluscs. Here we present the analyses to assess the potential pathogenic impact of V. furnissii. We compared the complete genome of V. furnissii with 8 other emerging and pathogenic Vibrio species. We selected and analyzed more deeply 10 genomic regions based upon unique or common features, and used 3 of these regions to construct a phylogenetic tree. Thus, we positioned V. furnissii more accurately than before and revealed a closer relationship between V. furnissii and V. cholerae than previously thought. However, V. furnissii lacks several important features normally associated with virulence in the human pathogens V. cholera and V. vulnificus. A striking feature of the V. furnissii genome is the hugely increased Super Integron, compared to the other Vibrio. Analyses of predicted genomic islands resulted in the discovery of a protein sequence that is present only in Vibrio associated with diseases in aquatic animals. We also discovered evidence of high levels horizontal gene transfer in V. furnissii. V. furnissii seems therefore to have a dynamic and fluid genome that could quickly adapt to environmental perturbation or increase its pathogenicity. Taken together, these analyses confirm the potential of V. furnissii as an emerging marine and possible human pathogen, especially in the developing, tropical, coastal regions that are most at risk from climate change.

Host specific glycans are correlated with susceptibility to infection by lagoviruses, but not with their virulence.

PubMed

Lopes, Ana M; Breiman, Adrien; Lora, Mónica; Le Moullac-Vaidye, Béatrice; Galanina, Oxana; Nyström, Kristina; Marchandeau, Stephane; Le Gall-Reculé, Ghislaine; Strive, Tanja; Neimanis, Aleksija; Bovin, Nicolai V; Ruvoën-Clouet, Nathalie; Esteves, Pedro J; Abrantes, Joana; Le Pendu, Jacques

2017-11-29

The rabbit hemorrhagic disease virus (RHDV) and the European brown hare syndrome virus (EBHSV) are two lagoviruses from the family Caliciviridae that cause fatal diseases in two leporid genera, Oryctolagus and Lepus , respectively. In the last few years, several examples of host jumps of lagoviruses among leporids were recorded. In addition, a new pathogenic genotype of RHDV emerged and many non-pathogenic strains of lagoviruses have been described. The molecular mechanisms behind host shifts and the emergence of virulence are unknown. Since RHDV uses glycans of the histo-blood group antigen type as attachment factors to initiate infection, we studied if glycan specificities of the new pathogenic RHDV genotype, non-pathogenic lagoviruses and EBHSV potentially play a role in determining host range and virulence of lagoviruses. We observed binding to A, B or H antigens of the histo-blood group family for all strains known to primarily infect European rabbits ( Oryctolagus cuniculus ), that have recently been classified as GI strains. Yet, we could not explain the emergence of virulence since similar glycan specificities were found between several pathogenic and non-pathogenic strains. By contrast, EBHSV, recently classified as GII.1, bound to terminal β-linked N-acetylglucosamine residues of O-glycans. Expression of these attachment factors in the upper respiratory and digestive tracts in three lagomorph species ( Oryctolagus cuniculus, Lepus europaeus and Sylvilagus floridanus ) showed species-specific patterns regarding the susceptibility to infection by these viruses, indicating that species-specific glycan expression is likely a major contributor to lagoviruses host specificity and range. IMPORTANCE Lagoviruses constitute a genus of the Caliciviridae family, comprising highly pathogenic viruses, RHDV and EBHSV, which infect rabbits and hares, respectively. Recently, non-pathogenic strains were discovered and new pathogenic strains have emerged. In addition, host jumps between lagomorphs are observed. The mechanisms responsible for the emergence of pathogenicity and host-species range are unknown. Previous studies showed that RHDV strains attach to glycans expressed in the upper respiratory and digestive tracts of rabbits, the likely doors of virus entry. Here we studied the glycan-binding properties of novel pathogenic and non-pathogenic strains looking for a link between glycan-binding and virulence or between glycan specificity and host range. We found that glycan binding did not correlate with virulence. However, expression of glycan motifs in the upper respiratory and digestive tracts of lagomorphs revealed species-specific patterns associated with the host range of the virus strains, suggesting that glycan diversity contributes to lagoviruses' host range. Copyright © 2017 American Society for Microbiology.

Evolution, Diversity, and Taxonomy of the Peronosporaceae, with Focus on the Genus Peronospora.

PubMed

Thines, Marco; Choi, Young-Joon

2016-01-01

Downy mildews are a notorious group of oomycete plant pathogens, causing high economic losses in various crops and ornamentals. The most species-rich genus of oomycetes is the genus Peronospora. This review provides a wide overview of these pathogens, ranging from macro- and micro-evolutionary patterns, their biodiversity and ecology to short overviews for the currently economically most important pathogens and potential emerging diseases. In this overview, the taxonomy of economically relevant species is also discussed, as the application of the correct names and species concepts is a prerequisite for effective quarantine regulations and phytosanitary measures.

Two pathogenic species of Pythium: P. aphanidermatum and P. diclinum from a wheat field.

PubMed

Al-Sheikh, Hashem

2010-10-01

During a survey of pathogenic and non-pathogenic Pythium spp. in different localities in Egypt, several isolates of Pythia were obtained and maintained on corn meal agar. Among these isolates, Pythium aphanidermatum and Pythium diclinum were obtained from rhizosphere of wheat plants grown in Dear Attia village, Minia, Egypt. Identification was made using morphological and molecular analyses. P. aphanidermatum and P. diclinum were able to cause reductions in emergence and adulating in wheat in laboratory scale. P. aphanidermatum appeared to be the most aggressive parasite under agar and pot experimental conditions.

Two pathogenic species of Pythium: P. aphanidermatum and P. diclinum from a wheat field

PubMed Central

Al-Sheikh, Hashem

2010-01-01

During a survey of pathogenic and non-pathogenic Pythium spp. in different localities in Egypt, several isolates of Pythia were obtained and maintained on corn meal agar. Among these isolates, Pythium aphanidermatum and Pythium diclinum were obtained from rhizosphere of wheat plants grown in Dear Attia village, Minia, Egypt. Identification was made using morphological and molecular analyses. P. aphanidermatum and P. diclinum were able to cause reductions in emergence and adulating in wheat in laboratory scale. P. aphanidermatum appeared to be the most aggressive parasite under agar and pot experimental conditions. PMID:23961096

Food-borne diseases - the challenges of 20 years ago still persist while new ones continue to emerge.

PubMed

Newell, Diane G; Koopmans, Marion; Verhoef, Linda; Duizer, Erwin; Aidara-Kane, Awa; Sprong, Hein; Opsteegh, Marieke; Langelaar, Merel; Threfall, John; Scheutz, Flemming; van der Giessen, Joke; Kruse, Hilde

2010-05-30

The burden of diseases caused by food-borne pathogens remains largely unknown. Importantly data indicating trends in food-borne infectious intestinal disease is limited to a few industrialised countries, and even fewer pathogens. It has been predicted that the importance of diarrhoeal disease, mainly due to contaminated food and water, as a cause of death will decline worldwide. Evidence for such a downward trend is limited. This prediction presumes that improvements in the production and retail of microbiologically safe food will be sustained in the developed world and, moreover, will be rolled out to those countries of the developing world increasingly producing food for a global market. In this review evidence is presented to indicate that the microbiological safety of food remains a dynamic situation heavily influenced by multiple factors along the food chain from farm to fork. Sustaining food safety standards will depend on constant vigilance maintained by monitoring and surveillance but, with the rising importance of other food-related issues, such as food security, obesity and climate change, competition for resources in the future to enable this may be fierce. In addition the pathogen populations relevant to food safety are not static. Food is an excellent vehicle by which many pathogens (bacteria, viruses/prions and parasites) can reach an appropriate colonisation site in a new host. Although food production practices change, the well-recognised food-borne pathogens, such as Salmonella spp. and Escherichia coli, seem able to evolve to exploit novel opportunities, for example fresh produce, and even generate new public health challenges, for example antimicrobial resistance. In addition, previously unknown food-borne pathogens, many of which are zoonotic, are constantly emerging. Current understanding of the trends in food-borne diseases for bacterial, viral and parasitic pathogens has been reviewed. The bacterial pathogens are exemplified by those well-recognized by policy makers; i.e. Salmonella, Campylobacter, E. coli and Listeria monocytogenes. Antimicrobial resistance in several bacterial food-borne pathogens (Salmonella, Campylobacter, Shigella and Vibrio spp., methicillin resistant Staphylcoccus aureas, E. coli and Enterococci) has been discussed as a separate topic because of its relative importance to policy issues. Awareness and surveillance of viral food-borne pathogens is generally poor but emphasis is placed on Norovirus, Hepatitis A, rotaviruses and newly emerging viruses such as SARS. Many food-borne parasitic pathogens are known (for example Ascaris, Cryptosporidia and Trichinella) but few of these are effectively monitored in foods, livestock and wildlife and their epidemiology through the food-chain is poorly understood. The lessons learned and future challenges in each topic are debated. It is clear that one overall challenge is the generation and maintenance of constructive dialogue and collaboration between public health, veterinary and food safety experts, bringing together multidisciplinary skills and multi-pathogen expertise. Such collaboration is essential to monitor changing trends in the well-recognised diseases and detect emerging pathogens. It will also be necessary understand the multiple interactions these pathogens have with their environments during transmission along the food chain in order to develop effective prevention and control strategies. Crown Copyright 2010. Published by Elsevier B.V. All rights reserved.

Phenotypic interactions between tree hosts and invasive forest pathogens in the light of globalization and climate change

PubMed Central

2016-01-01

Invasive pathogens can cause considerable damage to forest ecosystems. Lack of coevolution is generally thought to enable invasive pathogens to bypass the defence and/or recognition systems in the host. Although mostly true, this argument fails to predict intermittent outcomes in space and time, underlining the need to include the roles of the environment and the phenotype in host–pathogen interactions when predicting disease impacts. We emphasize the need to consider host–tree imbalances from a phenotypic perspective, considering the lack of coevolutionary and evolutionary history with the pathogen and the environment, respectively. We describe how phenotypic plasticity and plastic responses to environmental shifts may become maladaptive when hosts are faced with novel pathogens. The lack of host–pathogen and environmental coevolution are aligned with two global processes currently driving forest damage: globalization and climate change, respectively. We suggest that globalization and climate change act synergistically, increasing the chances of both genotypic and phenotypic imbalances. Short moves on the same continent are more likely to be in balance than if the move is from another part of the world. We use Gremmeniella abietina outbreaks in Sweden to exemplify how host–pathogen phenotypic interactions can help to predict the impacts of specific invasive and emergent diseases. This article is part of the themed issue ‘Tackling emerging fungal threats to animal health, food security and ecosystem resilience’. PMID:28080981

Phenotypic interactions between tree hosts and invasive forest pathogens in the light of globalization and climate change.

PubMed

Stenlid, Jan; Oliva, Jonàs

2016-12-05

Invasive pathogens can cause considerable damage to forest ecosystems. Lack of coevolution is generally thought to enable invasive pathogens to bypass the defence and/or recognition systems in the host. Although mostly true, this argument fails to predict intermittent outcomes in space and time, underlining the need to include the roles of the environment and the phenotype in host-pathogen interactions when predicting disease impacts. We emphasize the need to consider host-tree imbalances from a phenotypic perspective, considering the lack of coevolutionary and evolutionary history with the pathogen and the environment, respectively. We describe how phenotypic plasticity and plastic responses to environmental shifts may become maladaptive when hosts are faced with novel pathogens. The lack of host-pathogen and environmental coevolution are aligned with two global processes currently driving forest damage: globalization and climate change, respectively. We suggest that globalization and climate change act synergistically, increasing the chances of both genotypic and phenotypic imbalances. Short moves on the same continent are more likely to be in balance than if the move is from another part of the world. We use Gremmeniella abietina outbreaks in Sweden to exemplify how host-pathogen phenotypic interactions can help to predict the impacts of specific invasive and emergent diseases.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Author(s).

The influence of bacteria on multitrophic interactions among plants, psyllids, and pathogen.

PubMed

Tamborindeguy, Cecilia; Huot, Ordom Brian; Ibanez, Freddy; Levy, Julien

2017-12-01

The recent emergence of several plant diseases caused by psyllid-borne bacterial pathogens worldwide (Candidatus Liberibacter spp.) has created renewed interest on the interaction between psyllids and bacteria. In spite of these efforts to understand psyllid association with bacteria, many aspects of their interactions remain poorly understood. As more organisms are studied, subtleties on the molecular interactions as well as on the effects of the bacteria on the psyllid host are being uncovered. Additionally, psyllid-borne bacterial phytopathogens can also affect the host plant, which in turn can impact psyllid physiology and behavior. Here, we review the current literature on different aspects of the influence of bacteria on multitrophic interactions among plants, psyllids, and pathogens. We then highlight gaps that need to be addressed to advance this field, which can have significant implications for controlling these newly emergent and other plant diseases. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Antibiotic-non-antibiotic combinations for combating extremely drug-resistant Gram-negative 'superbugs'.

PubMed

Schneider, Elena K; Reyes-Ortega, Felisa; Velkov, Tony; Li, Jian

2017-02-28

The emergence of antimicrobial resistance of Gram-negative pathogens has become a worldwide crisis. The status quo for combating resistance is to employ synergistic combinations of antibiotics. Faced with this fast-approaching post-antibiotic era, it is critical that we devise strategies to prolong and maximize the clinical efficacy of existing antibiotics. Unfortunately, reports of extremely drug-resistant (XDR) Gram-negative pathogens have become more common. Combining antibiotics such as polymyxin B or the broad-spectrum tetracycline and minocycline with various FDA-approved non-antibiotic drugs have emerged as a novel combination strategy against otherwise untreatable XDR pathogens. This review surveys the available literature on the potential benefits of employing antibiotic-non-antibiotic drug combination therapy. The apex of this review highlights the clinical utility of this novel therapeutic strategy for combating infections caused by 'superbugs'. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Potential strategies and biosafety protocols used for dual-use research on highly pathogenic influenza viruses

PubMed Central

Du, Lanying; Li, Ye; Gao, Jimin; Zhou, Yusen; Jiang, Shibo

2013-01-01

Summary Influenza A viruses (IAVs), particularly the highly pathogenic avian influenza (HPAI) H5N1, have posed a substantial threat to public health worldwide. Although the laboratory generation of the mutant influenza virus H5N1 with airborne transmissibility among mammals, which has been considered as a dual-use research, may benefit the development of effective vaccines and therapeutics against the emerging infectious agents, it may also pose threats to national biosecurity, laboratory biosafety, and/or public health. This review introduces the classification and characterization of IAVs, pinpoints historic pandemics and epidemics caused by IAVs, emphasizes the significance and necessity of biosafety, summarizes currently established biosafety-related protocols for IAV research, and provides potential strategies to improve biosafety protocols for dual-use research on the highly pathogenic avian influenza viruses and other emerging infectious agents. PMID:22987727

Potential strategies and biosafety protocols used for dual-use research on highly pathogenic influenza viruses.

PubMed

Du, Lanying; Li, Ye; Gao, Jimin; Zhou, Yusen; Jiang, Shibo

2012-11-01

Influenza A viruses (IAVs), particularly the highly pathogenic avian influenza H5N1, have posed a substantial threat to public health worldwide. Although the laboratory generation of the mutant influenza virus H5N1 with airborne transmissibility among mammals, which has been considered as a dual-use research, may benefit the development of effective vaccines and therapeutics against the emerging infectious agents, it may also pose threats to national biosecurity, laboratory biosafety, and/or public health. This review introduces the classification and characterization of IAVs, pinpoints historic pandemics and epidemics caused by IAVs, emphasizes the significance and necessity of biosafety, summarizes currently established biosafety-related protocols for IAV research, and provides potential strategies to improve biosafety protocols for dual-use research on the highly pathogenic avian influenza viruses and other emerging infectious agents. Copyright © 2012 John Wiley & Sons, Ltd.

Mapping amphibian disease patterns

Treesearch

Noreen Parks

2013-01-01

Over the past two decades the worldwide emergence of the fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes chytridiomycosis, has drastically impacted populations of frogs, toads, and salamanders. Currently, as much as 40% of the roughly 6300 known amphibian species are deemed imperiled, and chytridiomycosis is...

Controlled fire use in early humans might have triggered the evolutionary emergence of tuberculosis.

PubMed

Chisholm, Rebecca H; Trauer, James M; Curnoe, Darren; Tanaka, Mark M

2016-08-09

Tuberculosis (TB) is caused by the Mycobacterium tuberculosis complex (MTBC), a wildly successful group of organisms and the leading cause of death resulting from a single bacterial pathogen worldwide. It is generally accepted that MTBC established itself in human populations in Africa and that animal-infecting strains diverged from human strains. However, the precise causal factors of TB emergence remain unknown. Here, we propose that the advent of controlled fire use in early humans created the ideal conditions for the emergence of TB as a transmissible disease. This hypothesis is supported by mathematical modeling together with a synthesis of evidence from epidemiology, evolutionary genetics, and paleoanthropology.

Ecosystem transformation by emerging infectious disease: loss of large tanoak from California forests

Treesearch

Richard C. Cobb; Joao A.N. Filipe; Ross K. Meentemeyer; Christopher A. Gilligan; David M. Rizzo

2012-01-01

1. Few pathogens are the sole or primary cause of species extinctions, but forest disease has caused spectacular declines in North American overstorey trees and restructured forest ecosystems at large spatial scales over the past 100 years. These events threaten biodiversity associated with impacted host trees and other resources valued by human societies even when...

Different cellular origins and functions of extracellular proteins from Escherichia coli O157:H7 and O104:H4 as determined by comparative proteomic analysis

USDA-ARS?s Scientific Manuscript database

Escherichia coli is a diverse species of bacteria, including several pathotypes that cause a variety of diseases in humans. Enterohemorrhagic E. coli (EHEC) and recently emerged shigatoxingenic enteroaggregative E. coli (EAEC) produce Shigatoxins and are major foodborne pathogens that can cause hem...

Detection of reassortant H5N6 clade 2.3.4.4 highly pathogenic avian influenza virus in a black-faced spoonbill (Platalea minor) found dead, Taiwan, 2017

USDA-ARS?s Scientific Manuscript database

H5N1 high pathogenicity avian influenza virus (HPAIV) emerged in 1996 in Guangdong China (A/goose/Guangdong/1/1996, Gs/GD) has caused outbreaks in over 80 countries throughout Eurasia, Africa, and North America. A H5N6 HPAIV clade 2.3.4.4, A/ black-faced spoonbill /Taiwan/DB645/2017 (SB/Tw/17), was ...

Leptospiral uveitis - there is more to it than meets the eye!

PubMed

Verma, A; Stevenson, B

2012-09-01

Leptospirosis, caused by pathogenic species of genus Leptospira, is a highly prevalent zoonotic disease throughout many parts of the world, and an important emerging disease within the United States. Uveitis is a common complication of systemic infection in humans. A similar condition in horses is characterized by recurrent bouts of inflammation. In this article, we review advances in our understanding of leptospiral uveitis and its pathogenic mechanisms. © 2012 Blackwell Verlag GmbH.

Batrachochytrium salamandrivorans and the risk of a second amphibian pandemic

USGS Publications Warehouse

Yap, Tiffany A.; Nguyen, Natalie T.; Serr, Megan; Shepak, Alex; Vredenburg, Vance

2017-01-01

Amphibians are experiencing devastating population declines globally. A major driver is chytridiomycosis, an emerging infectious disease caused by the fungal pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). Bdwas described in 1999 and has been linked with declines since the 1970s, while Bsal is a more recently discovered pathogen that was described in 2013. It is hypothesized that Bsaloriginated in Asia and spread via international trade to Europe, where it has been linked to salamander die-offs. Trade in live amphibians thus represents a significant threat to global biodiversity in amphibians. We review the current state of knowledge regarding Bsal and describe the risk of Bsal spread. We discuss regional responses to Bsal and barriers that impede a rapid, coordinated global effort. The discovery of a second deadly emerging chytrid fungal pathogen in amphibians poses an opportunity for scientists, conservationists, and governments to improve global biosecurity and further protect humans and wildlife from a growing number of emerging infectious diseases.

Tracking the emerging human pathogen Pseudallescheria boydii by using highly specific monoclonal antibodies.

PubMed

Thornton, Christopher R

2009-05-01

Pseudallescheria boydii has long been known to cause white grain mycetoma in immunocompetent humans, but it has recently emerged as an opportunistic pathogen of humans, causing potentially fatal invasive infections in immunocompromised individuals and evacuees of natural disasters, such as tsunamis and hurricanes. The diagnosis of P. boydii is problematic since it exhibits morphological characteristics similar to those of other hyaline fungi that cause infectious diseases, such as Aspergillus fumigatus and Scedosporium prolificans. This paper describes the development of immunoglobulin M (IgM) and IgG1 kappa-light chain monoclonal antibodies (MAbs) specific to P. boydii and certain closely related fungi. The MAbs bind to an immunodominant carbohydrate epitope on an extracellular 120-kDa antigen present in the spore and hyphal cell walls of P. boydii and Scedosporium apiospermum. The MAbs do not react with S. prolificans, Scedosporium dehoogii, or a large number of clinically relevant fungi, including A. fumigatus, Candida albicans, Cryptococcus neoformans, Fusarium solani, and Rhizopus oryzae. The MAbs were used in immunofluorescence and double-antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISAs) to accurately differentiate P. boydii from other infectious fungi and to track the pathogen in environmental samples. Specificity of the DAS-ELISA was confirmed by sequencing of the internally transcribed spacer 1 (ITS1)-5.8S-ITS2 rRNA-encoding regions of environmental isolates.

Protozoal agents: what are the dangers for the public water supply?

PubMed

Steiner, T S; Thielman, N M; Guerrant, R L

1997-01-01

Safe and efficient treatment of drinking water has been one of the major public health advances of the twentieth century. People in developed countries generally take for granted that their water is safe to drink, a luxury the majority of the world's population does not have. The leading cause of infant mortality in the developing world is infectious diarrhea, and the prevalence of diarrheal pathogens is largely influenced by the quality and quantity of clean water available for drinking and washing. Until recently, modern water treatment had all but eliminated these concerns in developed nations. Over the past two decades, however, the safety of our water supply has been threatened by the emergence of Cryptosporidium parvum, a protozoal pathogen. The hearty oocysts of this organism survive chlorination and filtration to cause a diarrheal illness that, while unpleasant enough in healthy people, is devastating in immunocompromised individuals. The 1993 Milwaukee outbreak, in which 403,000 people developed diarrhea from drinking water that met all the updated federal safety standards, demonstrated the tremendous public health importance of this organism. While earlier attention had focused on Giardia and amebic infections, the other "emerging" protozoan besides Cryptosporidium is Cyclospora. This review discusses the protozoal pathogens, including Cryptosporidium parvum, Giardia lamblia, Entamoeba histolytica, and Cyclospora cayetanensis, that cause waterborne diarrheal outbreaks and the threats they pose to the public.

Early emergence of Yersinia pestis as a severe respiratory pathogen

PubMed Central

Zimbler, Daniel L.; Schroeder, Jay A.; Eddy, Justin L.; Lathem, Wyndham W.

2015-01-01

Yersinia pestis causes the fatal respiratory disease pneumonic plague. Y. pestis recently evolved from the gastrointestinal pathogen Y. pseudotuberculosis; however, it is not known at what point Y. pestis gained the ability to induce a fulminant pneumonia. Here we show that the acquisition of a single gene encoding the protease Pla was sufficient for the most ancestral, deeply rooted strains of Y. pestis to cause pneumonic plague, indicating that Y. pestis was primed to infect the lungs at a very early stage in its evolution. As Y. pestis further evolved, modern strains acquired a single amino-acid modification within Pla that optimizes protease activity. While this modification is unnecessary to cause pneumonic plague, the substitution is instead needed to efficiently induce the invasive infection associated with bubonic plague. These findings indicate that Y. pestis was capable of causing pneumonic plague before it evolved to optimally cause invasive infections in mammals. PMID:26123398

Early emergence of Yersinia pestis as a severe respiratory pathogen.

PubMed

Zimbler, Daniel L; Schroeder, Jay A; Eddy, Justin L; Lathem, Wyndham W

2015-06-30

Yersinia pestis causes the fatal respiratory disease pneumonic plague. Y. pestis recently evolved from the gastrointestinal pathogen Y. pseudotuberculosis; however, it is not known at what point Y. pestis gained the ability to induce a fulminant pneumonia. Here we show that the acquisition of a single gene encoding the protease Pla was sufficient for the most ancestral, deeply rooted strains of Y. pestis to cause pneumonic plague, indicating that Y. pestis was primed to infect the lungs at a very early stage in its evolution. As Y. pestis further evolved, modern strains acquired a single amino-acid modification within Pla that optimizes protease activity. While this modification is unnecessary to cause pneumonic plague, the substitution is instead needed to efficiently induce the invasive infection associated with bubonic plague. These findings indicate that Y. pestis was capable of causing pneumonic plague before it evolved to optimally cause invasive infections in mammals.

Fungi from a Groundwater-Fed Drinking Water Supply System in Brazil

PubMed Central

Oliveira, Helena M.B.; Santos, Cledir; Paterson, R. Russell M.; Gusmão, Norma B.; Lima, Nelson

2016-01-01

Filamentous fungi in drinking water distribution systems are known to (a) block water pipes; (b) cause organoleptic biodeterioration; (c) act as pathogens or allergens and (d) cause mycotoxin contamination. Yeasts might also cause problems. This study describes the occurrence of several fungal species in a water distribution system supplied by groundwater in Recife—Pernambuco, Brazil. Water samples were collected from four sampling sites from which fungi were recovered by membrane filtration. The numbers in all sampling sites ranged from 5 to 207 colony forming units (CFU)/100 mL with a mean value of 53 CFU/100 mL. In total, 859 isolates were identified morphologically, with Aspergillus and Penicillium the most representative genera (37% and 25% respectively), followed by Trichoderma and Fusarium (9% each), Curvularia (5%) and finally the species Pestalotiopsis karstenii (2%). Ramichloridium and Leptodontium were isolated and are black yeasts, a group that include emergent pathogens. The drinking water system in Recife may play a role in fungal dissemination, including opportunistic pathogens. PMID:27005653

Fungi from a Groundwater-Fed Drinking Water Supply System in Brazil.

PubMed

Oliveira, Helena M B; Santos, Cledir; Paterson, R Russell M; Gusmão, Norma B; Lima, Nelson

2016-03-09

Filamentous fungi in drinking water distribution systems are known to (a) block water pipes; (b) cause organoleptic biodeterioration; (c) act as pathogens or allergens and (d) cause mycotoxin contamination. Yeasts might also cause problems. This study describes the occurrence of several fungal species in a water distribution system supplied by groundwater in Recife-Pernambuco, Brazil. Water samples were collected from four sampling sites from which fungi were recovered by membrane filtration. The numbers in all sampling sites ranged from 5 to 207 colony forming units (CFU)/100 mL with a mean value of 53 CFU/100 mL. In total, 859 isolates were identified morphologically, with Aspergillus and Penicillium the most representative genera (37% and 25% respectively), followed by Trichoderma and Fusarium (9% each), Curvularia (5%) and finally the species Pestalotiopsis karstenii (2%). Ramichloridium and Leptodontium were isolated and are black yeasts, a group that include emergent pathogens. The drinking water system in Recife may play a role in fungal dissemination, including opportunistic pathogens.

Extreme sensitivity to ultraviolet light in the fungal pathogen causing white-nose syndrome of bats.

PubMed

Palmer, Jonathan M; Drees, Kevin P; Foster, Jeffrey T; Lindner, Daniel L

2018-01-02

Bat white-nose syndrome (WNS), caused by the fungal pathogen Pseudogymnoascus destructans, has decimated North American hibernating bats since its emergence in 2006. Here, we utilize comparative genomics to examine the evolutionary history of this pathogen in comparison to six closely related nonpathogenic species. P. destructans displays a large reduction in carbohydrate-utilizing enzymes (CAZymes) and in the predicted secretome (~50%), and an increase in lineage-specific genes. The pathogen has lost a key enzyme, UVE1, in the alternate excision repair (AER) pathway, which is known to contribute to repair of DNA lesions induced by ultraviolet (UV) light. Consistent with a nonfunctional AER pathway, P. destructans is extremely sensitive to UV light, as well as the DNA alkylating agent methyl methanesulfonate (MMS). The differential susceptibility of P. destructans to UV light in comparison to other hibernacula-inhabiting fungi represents a potential "Achilles' heel" of P. destructans that might be exploited for treatment of bats with WNS.

Label-free detection of salmonella typhimurium with ssDNA aptamers

USDA-ARS?s Scientific Manuscript database

Foodborne pathogen Salmonella enterica is one of the major causes of gastrointestinal infections in human and animals. Conventional detection methods are time consuming and not effective enough under emergency circumstances to control outbreaks immediately. Therefore, biosensors that can detect Salm...

Immune modulation of host response to coccidiosis and necrotic enteritis to reduce antibiotics

USDA-ARS?s Scientific Manuscript database

Multiple challenges confront the rising demand for poultry food products, including governmental restrictions on the use of antibiotic growth promoters, high-density production conditions, waste management, and the emergence of infectious pathogens, particularly those that cause intestinal diseases....

*Environmental mycobacteriosis and drinking water: an emerging problem for developed countries

EPA Science Inventory

Background and Objective: Rates ofpulmonary environmental mycobacteriosis (EM) appear to be increasing among developed countries during the past 20 years. EM is caused by multiple species of pathogenic mycobacteria that have been recovered from soil, water, water aerosols, biofil...

In vitro synergistic effects of fisetin and norfloxacin against aquatic isolates of Serratia marcescens.

PubMed

Dong, Jing; Ruan, Jing; Xu, Ning; Yang, Yibin; Ai, Xiaohui

2016-01-01

Serratia marcescens is a common pathogenic bacterium that can cause infections in both humans and animals. It can cause a range of diseases, from slight wound infections to life-threatening bacteraemia and pneumonia. The emergence of antimicrobial resistance has limited the treatment of the diseases caused by the bacterium to a great extent. Consequently, there is an urgent need to develop novel antimicrobial strategies against this pathogen. Synergistic strategy is a new approach to treat the infections caused by drug-resistant bacteria. In this paper, we isolated and identified the first multi-resistant pathogenic Serratia marcescens strain from diseased soft-shelled turtles (Pelodiscus sinensis) in China. We then performed a checkerboard assay; the results showed that out of 10 tested natural products fisetin had synergistic effects against S. marcescens when combined with norfloxacin. The time-kill curve assay further confirmed the results of the checkerboard assay. We found that this novel synergistic effect could significantly reduce the dosage of norfloxacin against S. marcescens. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Molecular pathogenesis of H5 highly pathogenic avian influenza: the role of the haemagglutinin cleavage site motif

PubMed Central

Luczo, Jasmina M.; Stambas, John; Durr, Peter A.; Michalski, Wojtek P.

2015-01-01

Summary The emergence of H5N1 highly pathogenic avian influenza has caused a heavy socio‐economic burden through culling of poultry to minimise human and livestock infection. Although human infections with H5N1 have to date been limited, concerns for the pandemic potential of this zoonotic virus have been greatly intensified following experimental evidence of aerosol transmission of H5N1 viruses in a mammalian infection model. In this review, we discuss the dominance of the haemagglutinin cleavage site motif as a pathogenicity determinant, the host‐pathogen molecular interactions driving cleavage activation, reverse genetics manipulations and identification of residues key to haemagglutinin cleavage site functionality and the mechanisms of cell and tissue damage during H5N1 infection. We specifically focus on the disease in chickens, as it is in this species that high pathogenicity frequently evolves and from which transmission to the human population occurs. With >75% of emerging infectious diseases being of zoonotic origin, it is necessary to understand pathogenesis in the primary host to explain spillover events into the human population. © 2015 The Authors. Reviews in Medical Virology published by John Wiley & Sons Ltd. PMID:26467906

Pathogenic human viruses in coastal waters

USGS Publications Warehouse

Griffin, Dale W.; Donaldson, Kim A.; Paul, J.H.; Rose, Joan B.

2003-01-01

This review addresses both historical and recent investigations into viral contamination of marine waters. With the relatively recent emergence of molecular biology-based assays, a number of investigations have shown that pathogenic viruses are prevalent in marine waters being impacted by sewage. Research has shown that this group of fecal-oral viral pathogens (enteroviruses, hepatitis A viruses, Norwalk viruses, reoviruses, adenoviruses, rotaviruses, etc.) can cause a broad range of asymptomatic to severe gastrointestinal, respiratory, and eye, nose, ear, and skin infections in people exposed through recreational use of the water. The viruses and the nucleic acid signature survive for an extended period in the marine environment. One of the primary concerns of public health officials is the relationship between the presence of pathogens and the recreational risk to human health in polluted marine environments. While a number of studies have attempted to address this issue, the relationship is still poorly understood. A contributing factor to our lack of progress in the field has been the lack of sensitive methods to detect the broad range of both bacterial and viral pathogens. The application of new and advanced molecular methods will continue to contribute to our current state of knowledge in this emerging and

[Predictors of drug-resistant pathogens in community-onset pneumonia: Are factors considered in health-care-associated pneumonia useful in the emergency department?

PubMed

Torres Bonafonte, Olga H; Gil Olivas, Eva; Pérez Macho, Estefanía; Pacho Pacho, Cristina; Mateo Roca, Miriam; Casademont Pou, Jordi; Ruiz Hidalgo, Domingo

2017-10-01

To analyze factors related to drug-resistant pathogens (DRPs) in community-onset pneumonia (COP) and whether previously suggested criteria are useful in our emergency-department. Prospective 1-year study of adults coming to the emergency department for COP. We assessed the usefulness of criteria used in health-care-associated pneumonia (HCAP), as well the Shorr index, the Barthel index, and clinical suspicion of resistant pathogens. Data were analyzed by multiple logistic regression and the area under the receiver operating characteristic curve (AUC). We included 139 patients with a mean (SD) age of 75.9 (15.3) years; 63.3% were men. Forty-nine COP patients (35.2%) were at risk for DRP-caused pneumonia according to HCAP criteria; 43 (30.9%) according to the Shorr index, and 56 (40.3%) according to the Aliberti index. A score of less than 60 derived from the Barthel index was recorded for 25 patients (18%). Clinical suspicion of a DRP was recorded for 11 (7.9%). A DRP was isolated in 5 patients (3.6%) (3, Pseudomonas aeruginosa; 2, methicillin-resistant Staphylococcus aureus). Multiple logistic regression analysis identified 2 predictors of DRP-caused COP: hospital admission within the last 90 days (odds ratio [OR], 8.92; 95% CI, 1.92-41.45) and initial arterial blood oxygen saturation (OR, 0.85; 95% CI, 0.74-0.98). The AUC was 0.91 (95% CI, 0.85-0.98). The model identified 22 patients (16.8%) at risk for DRP-caused pneumonia. The positive and negative predictive values were 20% and 99.1%, respectively, for the model 90-day period (vs 8.7% and 98.9%, respectively, for criteria used in HCAP). Hospitalization within the 90-day period before a COP emergency and arterial blood oxygen saturation were good predictors of DRP in our setting. Criteria of DRP in HCAP, on the other hand, had lower ability to identify patients at risk in COP.

From SARS to MERS: 10 years of research on highly pathogenic human coronaviruses.

PubMed

Hilgenfeld, Rolf; Peiris, Malik

2013-10-01

This article introduces a series of invited papers in Antiviral Research marking the 10th anniversary of the outbreak of severe acute respiratory syndrome (SARS), caused by a novel coronavirus that emerged in southern China in late 2002. Until that time, coronaviruses had not been recognized as agents causing severe disease in humans, hence, the emergence of the SARS-CoV came as a complete surprise. Research during the past ten years has revealed the existence of a diverse pool of coronaviruses circulating among various bat species and other animals, suggesting that further introductions of highly pathogenic coronaviruses into the human population are not merely probable, but inevitable. The recent emergence of another coronavirus causing severe disease, Middle East respiratory syndrome (MERS), in humans, has made it clear that coronaviruses pose a major threat to human health, and that more research is urgently needed to elucidate their replication mechanisms, identify potential drug targets, and develop effective countermeasures. In this series, experts in many different aspects of coronavirus replication and disease will provide authoritative, up-to-date reviews of the following topics: - clinical management and infection control of SARS; - reservoir hosts of coronaviruses; - receptor recognition and cross-species transmission of SARS-CoV; - SARS-CoV evasion of innate immune responses; - structures and functions of individual coronaviral proteins; - anti-coronavirus drug discovery and development; and - the public health legacy of the SARS outbreak. Each article will be identified in the last line of its abstract as belonging to the series "From SARS to MERS: 10years of research on highly pathogenic human coronaviruses." Copyright © 2013 Elsevier B.V. All rights reserved.

Mortality and community changes drive sudden oak death impacts on litterfall and soil nitrogen cycling.

PubMed

Cobb, Richard C; Eviner, Valerie T; Rizzo, David M

2013-10-01

Few studies have quantified pathogen impacts to ecosystem processes, despite the fact that pathogens cause or contribute to regional-scale tree mortality. We measured litterfall mass, litterfall chemistry, and soil nitrogen (N) cycling associated with multiple hosts along a gradient of mortality caused by Phytophthora ramorum, the cause of sudden oak death. In redwood forests, the epidemiological and ecological characteristics of the major overstory species determine disease patterns and the magnitude and nature of ecosystem change. Bay laurel (Umbellularia californica) has high litterfall N (0.992%), greater soil extractable NO3 -N, and transmits infection without suffering mortality. Tanoak (Notholithocarpus densiflorus) has moderate litterfall N (0.723%) and transmits infection while suffering extensive mortality that leads to higher extractable soil NO3 -N. Redwood (Sequoia sempervirens) has relatively low litterfall N (0.519%), does not suffer mortality or transmit the pathogen, but dominates forest biomass. The strongest impact of pathogen-caused mortality was the potential shift in species composition, which will alter litterfall chemistry, patterns and dynamics of litterfall mass, and increase soil NO3 -N availability. Patterns of P. ramorum spread and consequent mortality are closely associated with bay laurel abundances, suggesting this species will drive both disease emergence and subsequent ecosystem function. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Major emerging and re-emerging zoonoses in China: a matter of global health and socioeconomic development for 1.3 billion.

PubMed

Liu, Quan; Cao, Lili; Zhu, Xing-Quan

2014-08-01

Emerging and re-emerging zoonoses are a significant public health concern and cause considerable socioeconomic problems globally. The emergence of severe acute respiratory syndrome (SARS), highly pathogenic avian influenza (HPAI) H5N1, avian influenza H7N9, and severe fever with thrombocytopenia syndrome (SFTS), and the re-emergence of rabies, brucellosis, and other zoonoses have had a significant effect on the national economy and public health in China, and have affected other countries. Contributing factors that continue to affect emerging and re-emerging zoonoses in China include social and environmental factors and microbial evolution, such as population growth, urbanization, deforestation, livestock production, food safety, climate change, and pathogen mutation. The Chinese government has devised new strategies and has taken measures to deal with the challenges of these diseases, including the issuing of laws and regulations, establishment of disease reporting systems, implementation of special projects for major infectious diseases, interdisciplinary and international cooperation, exotic disease surveillance, and health education. These strategies and measures can serve as models for the surveillance and response to continuing threats from emerging and re-emerging zoonoses in other countries. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Emerging Trends in Molecular Interactions between Plants and the Broad Host Range Fungal Pathogens Botrytis cinerea and Sclerotinia sclerotiorum

PubMed Central

Mbengue, Malick; Navaud, Olivier; Peyraud, Rémi; Barascud, Marielle; Badet, Thomas; Vincent, Rémy; Barbacci, Adelin; Raffaele, Sylvain

2016-01-01

Fungal plant pathogens are major threats to food security worldwide. Sclerotinia sclerotiorum and Botrytis cinerea are closely related Ascomycete plant pathogens causing mold diseases on hundreds of plant species. There is no genetic source of complete plant resistance to these broad host range pathogens known to date. Instead, natural plant populations show a continuum of resistance levels controlled by multiple genes, a phenotype designated as quantitative disease resistance. Little is known about the molecular mechanisms controlling the interaction between plants and S. sclerotiorum and B. cinerea but significant advances were made on this topic in the last years. This minireview highlights a selection of nine themes that emerged in recent research reports on the molecular bases of plant-S. sclerotiorum and plant-B. cinerea interactions. On the fungal side, this includes progress on understanding the role of oxalic acid, on the study of fungal small secreted proteins. Next, we discuss the exchanges of small RNA between organisms and the control of cell death in plant and fungi during pathogenic interactions. Finally on the plant side, we highlight defense priming by mechanical signals, the characterization of plant Receptor-like proteins and the hormone abscisic acid in the response to B. cinerea and S. sclerotiorum, the role of plant general transcription machinery and plant small bioactive peptides. These represent nine trends we selected as remarkable in our understanding of fungal molecules causing disease and plant mechanisms associated with disease resistance to two devastating broad host range fungi. PMID:27066056

Streptococcus dysgalactiae subsp. dysgalactiae isolated from milk of the bovine udder as emerging pathogens: In vitro and in vivo infection of human cells and zebrafish as biological models.

PubMed

Alves-Barroco, Cinthia; Roma-Rodrigues, Catarina; Raposo, Luís R; Brás, Catarina; Diniz, Mário; Caço, João; Costa, Pedro M; Santos-Sanches, Ilda; Fernandes, Alexandra R

2018-03-25

Streptococcus dysgalactiae subsp. dysgalactiae (SDSD) is a major cause of bovine mastitis and has been regarded as an animal-restricted pathogen, although rare infections have been described in humans. Previous studies revealed the presence of virulence genes encoded by phages of the human pathogen Group A Streptococcus pyogenes (GAS) in SDSD isolated from the milk of bovine udder with mastitis. The isolates SDSD VSD5 and VSD13 could adhere and internalize human primary keratinocyte cells, suggesting a possible human infection potential of bovine isolates. In this work, the in vitro and in vivo potential of SDSD to internalize/adhere human cells of the respiratory track and zebrafish as biological models was evaluated. Our results showed that, in vitro, bovine SDSD strains could interact and internalize human respiratory cell lines and that this internalization was dependent on an active transport mechanism and that, in vivo, SDSD are able to cause invasive infections producing zebrafish morbidity and mortality. The infectious potential of these isolates showed to be isolate-specific and appeared to be independent of the presence or absence of GAS phage-encoded virulence genes. Although the infection ability of the bovine SDSD strains was not as strong as the human pathogenic S. pyogenes in the zebrafish model, results suggested that these SDSD isolates are able to interact with human cells and infect zebrafish, a vertebrate infectious model, emerging as pathogens with zoonotic capability. © 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Emerging Coxsackievirus A6 Causing Hand, Foot and Mouth Disease, Vietnam

PubMed Central

Anh, Nguyen To; Nhu, Le Nguyen Truc; Van, Hoang Minh Tu; Hong, Nguyen Thi Thu; Thanh, Tran Tan; Hang, Vu Thi Ty; Ny, Nguyen Thi Han; Nguyet, Lam Anh; Phuong, Tran Thi Lan; Nhan, Le Nguyen Thanh; Hung, Nguyen Thanh; Khanh, Truong Huu; Tuan, Ha Manh; Viet, Ho Lu; Nam, Nguyen Tran; Viet, Do Chau; Qui, Phan Tu; Wills, Bridget; Sabanathan, Sarawathy; Chau, Nguyen Van Vinh; Thwaites, Louise; Rogier van Doorn, H.; Thwaites, Guy; Rabaa, Maia A.

2018-01-01

Hand, foot and mouth disease (HFMD) is a major public health issue in Asia and has global pandemic potential. Coxsackievirus A6 (CV-A6) was detected in 514/2,230 (23%) of HFMD patients admitted to 3 major hospitals in southern Vietnam during 2011–2015. Of these patients, 93 (18%) had severe HFMD. Phylogenetic analysis of 98 genome sequences revealed they belonged to cluster A and had been circulating in Vietnam for 2 years before emergence. CV-A6 movement among localities within Vietnam occurred frequently, whereas viral movement across international borders appeared rare. Skyline plots identified fluctuations in the relative genetic diversity of CV-A6 corresponding to large CV-A6–associated HFMD outbreaks worldwide. These data show that CV-A6 is an emerging pathogen and emphasize the necessity of active surveillance and understanding the mechanisms that shape the pathogen evolution and emergence, which is essential for development and implementation of intervention strategies. PMID:29553326

Homologous and heterologous antigenic matched vaccines containing different H5 hemagglutinins provides variable protection of chickens from the 2014 U.S. H5N8 and H5N2 clade 2.3.4.4 highly pathogenic avian influenza viruses

USDA-ARS?s Scientific Manuscript database

From December 2014 to June 2015, a novel H5 Eurasian A/goose/Guangdong (Gs/GD) lineage clade 2.3.4.4 high pathogenicity avian influenza (HPAI) virus caused the largest animal health emergency in US history resulting in mortality or culling of greater than 48 million poultry. The outbreak renewed int...

MERS, SARS and other coronaviruses as causes of pneumonia.

PubMed

Yin, Yudong; Wunderink, Richard G

2018-02-01

Human coronaviruses (HCoVs) have been considered to be relatively harmless respiratory pathogens in the past. However, after the outbreak of the severe acute respiratory syndrome (SARS) and emergence of the Middle East respiratory syndrome (MERS), HCoVs have received worldwide attention as important pathogens in respiratory tract infection. This review focuses on the epidemiology, pathogenesis and clinical characteristics among SARS-coronaviruses (CoV), MERS-CoV and other HCoV infections. © 2017 Asian Pacific Society of Respirology.

Reduced experimental infectivity and transmissibility of intercontinental H5 (H5N8 and H5N2) compared to Eurasian H5N1 highly pathogenic avian influenza viruses for chickens, turkeys, and Japanese quail

USDA-ARS?s Scientific Manuscript database

H5N1 high pathogenicity avian influenza (HPAI) virus (HPAIV) emerged in 1996 in Guangdong China and has since spread to infect and cause deaths in wild birds, poultry and humans in over 63 countries in Asia, Europe and Africa; and more recently a reassortant H5N8 clade 2.3.4.4 HPAI virus has spread ...

Water relations in the interaction of foliar bacterial pathogens with plants.

PubMed

Beattie, Gwyn A

2011-01-01

This review examines the many ways in which water influences the relations between foliar bacterial pathogens and plants. As a limited resource in aerial plant tissues, water is subject to manipulation by both plants and pathogens. A model is emerging that suggests that plants actively promote localized desiccation at the infection site and thus restrict pathogen growth as one component of defense. Similarly, many foliar pathogens manipulate water relations as one component of pathogenesis. Nonvascular pathogens do this using effectors and other molecules to alter hormonal responses and enhance intercellular watersoaking, whereas vascular pathogens use many mechanisms to cause wilt. Because of water limitations on phyllosphere surfaces, bacterial colonists, including pathogens, benefit from the protective effects of cellular aggregation, synthesis of hygroscopic polymers, and uptake and production of osmoprotective compounds. Moreover, these bacteria employ tactics for scavenging and distributing water to overcome water-driven barriers to nutrient acquisition, movement, and signal exchange on plant surfaces. Copyright © 2011 by Annual Reviews. All rights reserved.

Genome plasticity in filamentous plant pathogens contributes to the emergence of novel effectors and their cellular processes in the host.

PubMed

Dong, Yanhan; Li, Ying; Qi, Zhongqiang; Zheng, Xiaobo; Zhang, Zhengguang

2016-02-01

Plant diseases cause extensive yield loss of crops worldwide, and secretory 'warfare' occurs between plants and pathogenic organisms all the time. Filamentous plant pathogens have evolved the ability to manipulate host processes and facilitate colonization through secreting effectors inside plant cells. The stresses from hosts and environment can drive the genome dynamics of plant pathogens. Remarkable advances in plant pathology have been made owing to these adaptable genome regions of several lineages of filamentous phytopathogens. Characterization new effectors and interaction analyses between pathogens and plants have provided molecular insights into the plant pathways perturbed during the infection process. In this mini-review, we highlight promising approaches of identifying novel effectors based on the genome plasticity. We also discuss the interaction mechanisms between plants and their filamentous pathogens and outline the possibilities of effector gene expression under epigenetic control that will be future directions for research.

Regeneration and tanoak mortality in coast redwood stands affected by sudden oak death

Treesearch

Benjamin S. Ramage; Kevin L. OHara; Alison B. Forreste

2012-01-01

Sudden oak death, an emerging disease caused by the exotic pathogen Phytophthora ramorum, is impacting coast redwood (Sequoia sempervirens) forests throughout coastal California. The most severely affected species, tanoak (Notholithocarpus densiflorus), is currently widespread and abundant in the redwood...

Tolerance to Phytophthora Fruit Rot in Watermelon Plant Introductions

USDA-ARS?s Scientific Manuscript database

Phytophthora capsici is distributed worldwide, and is an aggressive pathogen with a broad host range infecting solanaceous, leguminaceous, and cucurbitaceous crops. Fruit rot, caused by P. capsici is an emerging disease in most watermelon producing regions of Southeast US. Resistance to fruit rot o...

Consensus guidelines for the treatment of invasive mould infections in haematological malignancy and haemopoietic stem cell transplantation, 2014.

PubMed

Blyth, C C; Gilroy, N M; Guy, S D; Chambers, S T; Cheong, E Y; Gottlieb, T; McGuinness, S L; Thursky, K A

2014-12-01

Mould species represent the pathogens most commonly associated with invasive fungal disease in patients with haematological malignancies and patients of haemopoietic stem cell transplants. Invasive mould infections in these patient populations, particularly in the setting of neutropenia, are associated with high morbidity and mortality, and significantly increase the complexity of management. While Aspergillus species remain the most prevalent cause of invasive mould infections, Scedosporium and Fusarium species and the Mucormycetes continue to place a significant burden on the immunocompromised host. Evidence also suggests that infections caused by rare and emerging pathogens are increasing within the setting of broad-spectrum antifungal prophylaxis and improved survival times placing immunosuppressed patients at risk for longer. These guidelines present evidence-based recommendations for the antifungal management of common, rare and emerging mould infections in both adult and paediatric populations. Where relevant, the role of surgery, adjunctive therapy and immunotherapy is also discussed. © 2014 The Authors; Internal Medicine Journal © 2014 Royal Australasian College of Physicians.

How the biodiversity sciences may aid biological tools and ecological engineering to assess the impact of climatic changes.

PubMed

Morand, S; Guégan, J-F

2008-08-01

This paper addresses how climate changes interact with other global changes caused by humans (habitat fragmentation, changes in land use, bioinvasions) to affect biodiversity. Changes in biodiversity at all levels (genetic, population and community) affect the functioning of ecosystems, in particular host-pathogen interactions, with major consequences in health ecology (emergence and re-emergence; the evolution of virulence and resistance). In this paper, the authors demonstrate that the biodiversity sciences, epidemiological theory and evolutionary ecology are indispensable in assessing the impact of climate changes, and also for modelling the evolution of host-pathogen interactions in a changing environment. The next step is to apply health ecology to the science of ecological engineering.

Pathogenic psychrotolerant sporeformers: an emerging challenge for low-temperature storage of minimally processed foods.

PubMed

Markland, Sarah M; Farkas, Daniel F; Kniel, Kalmia E; Hoover, Dallas G

2013-05-01

Sporeforming bacteria are a significant problem in the food industry as they are ubiquitous in nature and capable of resisting inactivation by heat and chemical treatments designed to inactivate them. Beyond spoilage issues, psychrotolerant sporeformers are becoming increasingly recognized as a potential hazard given the ever-expanding demand for refrigerated processed foods with extended shelf-life. In these products, the sporeforming pathogens of concern are Bacillus cereus, Bacillus weihenstephanensis, and Clostridium botulinum type E. This review article examines the foods, conditions, and organisms responsible for the food safety issue caused by the germination and outgrowth of psychrotolerant sporeforming pathogens in minimally processed refrigerated foods.

Comparison of the h-Index Scores Among Pathogens Identified as Emerging Hazards in North America.

PubMed

Cox, R; McIntyre, K M; Sanchez, J; Setzkorn, C; Baylis, M; Revie, C W

2016-02-01

Disease surveillance must assess the relative importance of pathogen hazards. Here, we use the Hirsch index (h-index) as a novel method to identify and rank infectious pathogens that are likely to be a hazard to human health in the North American region. This bibliometric index was developed to quantify an individual's scientific research output and was recently used as a proxy measure for pathogen impact. Analysis of more than 3000 infectious organisms indicated that 651 were human pathogen species that had been recorded in the North American region. The h-index of these pathogens ranged from 0 to 584. The h-index of emerging pathogens was greater than non-emerging pathogens as was the h-index of frequently pathogenic pathogens when compared to non-pathogenic pathogens. As expected, the h-index of pathogens varied over time between 1960 and 2011. We discuss how the h-index can contribute to pathogen prioritization and as an indicator of pathogen emergence. © 2014 Blackwell Verlag GmbH.

Promiscuous Pathogenicity Islands and Phylogeny of Pathogenic Streptomyces spp.

PubMed

Zhang, Yucheng; Bignell, Dawn R D; Zuo, Ran; Fan, Qiurong; Huguet-Tapia, Jose C; Ding, Yousong; Loria, Rosemary

2016-08-01

Approximately 10 Streptomyces species cause disease on underground plant structures. The most economically important of these is potato scab, and the most studied of these pathogens is Streptomyces scabiei (syn. S. scabies). The main pathogenicity determinant of scab-causing Streptomyces species is a nitrated diketopiperazine, known as thaxtomin A (ThxA). In the pathogenic species Streptomyces turgidiscabies, ThxA biosynthetic genes reside on a mobile pathogenicity island (PAI). However, the mobilization of PAIs in other Streptomyces species remains uncharacterized. Here, we investigated the mobilization of the PAI of S. scabiei 87-22. Based on whole genome sequences, we inferred the evolutionary relationships of pathogenic Streptomyces species and discovered that Streptomyces sp. strain 96-12, a novel pathogenic species isolated from potatoes in Egypt, was phylogenetically grouped with nonpathogenic species rather than with known pathogenic species. We also found that Streptomyces sp. strain 96-12 contains a PAI that is almost identical to the PAI in S. scabiei 87-22, despite significant differences in their genome sequences. This suggested direct or indirect in vivo mobilization of the PAI between S. scabiei and nonpathogenic Streptomyces species. To test whether the S. scabiei 87-22 PAI could, indeed, be mobilized, S. scabiei 87-22 deletion mutants containing antibiotic resistance markers in the PAI were mated with Streptomyces diastatochromogenes, a nonpathogenic species. The PAI of S. scabiei was site-specifically inserted into the aviX1 gene of S. diastatochromogenes and conferred pathogenicity in radish seedling assays. Our results demonstrated that S. scabiei, the earliest described Streptomyces pathogen, could be the source of a PAI responsible for the emergence of novel pathogenic species.

Common Features of Opportunistic Premise Plumbing Pathogens

PubMed Central

Falkinham, Joseph O.

2015-01-01

Recently it has been estimated that the annual cost of diseases caused by the waterborne pathogens Legionella pneumonia, Mycobacterium avium, and Pseudomonas aeruginosa is $500 million. For the period 2001–2012, the estimated cost of hospital admissions for nontuberculous mycobacterial pulmonary disease, the majority caused by M. avium, was almost $1 billion. These three waterborne opportunistic pathogens are normal inhabitants of drinking water—not contaminants—that share a number of key characteristics that predispose them to survival, persistence, and growth in drinking water distribution systems and premise plumbing. Herein, I list and describe these shared characteristics that include: disinfectant-resistance, biofilm-formation, growth in amoebae, growth at low organic carbon concentrations (oligotrophic), and growth under conditions of stagnation. This review is intended to increase awareness of OPPPs, identify emerging OPPPs, and challenge the drinking water industry to develop novel approaches toward their control. PMID:25918909

Pathogenicity and genetic characterization of a duck Tembusu virus associated with egg-dropping in Muscovy ducks.

PubMed

Shen, Han-Qin; Lin, Wen-Cheng; Wang, Zhan-Xin; Zhang, Kai; Yan, Zhuan-Qiang; Zhou, Qing-Feng; Qin, Jian-Ping; Xie, Qing-Mei; Bi, Ying-Zuo; Chen, Feng

2016-09-02

Duck Tembusu virus (DTMUV) has spread to the major duck-farming region in China, causing acute egg-production drop in Chinese duck population. In this study, we characterized a DTMUV strain (named GD2014) isolated from an egg-production drop duck farm in Guangdong province, South China. The virus was pathogenic to Muscovy duck embryos and caused severe egg production drop for laying Muscovy ducks. The genome sequence of GD2014 shared 97-99% homologies with other waterfowl-origin Tembusu viruses, and shared 89% identities with MM1775 strain isolated from mosquito. Phylogenetic analysis of entire open reading frame (ORF), E gene and NS5 gene indicated that GD2014 belonged to Ntaya group. These results have implications for understanding the orgin, emergence and pathogenicity of DTMUV as well as for the development of vaccines and diagnostics based on epidemiological data. Copyright © 2016 Elsevier B.V. All rights reserved.

The Causes and Consequences of Changes in Virulence following Pathogen Host Shifts

PubMed Central

Longdon, Ben; Hadfield, Jarrod D.; Day, Jonathan P.; Smith, Sophia C. L.; McGonigle, John E.; Cogni, Rodrigo; Cao, Chuan; Jiggins, Francis M.

2015-01-01

Emerging infectious diseases are often the result of a host shift, where the pathogen originates from a different host species. Virulence—the harm a pathogen does to its host—can be extremely high following a host shift (for example Ebola, HIV, and SARs), while other host shifts may go undetected as they cause few symptoms in the new host. Here we examine how virulence varies across host species by carrying out a large cross infection experiment using 48 species of Drosophilidae and an RNA virus. Host shifts resulted in dramatic variation in virulence, with benign infections in some species and rapid death in others. The change in virulence was highly predictable from the host phylogeny, with hosts clustering together in distinct clades displaying high or low virulence. High levels of virulence are associated with high viral loads, and this may determine the transmission rate of the virus. PMID:25774803

Genome characterization and population genetic structure of the zoonotic pathogen, Streptococcus canis

PubMed Central

2012-01-01

Background Streptococcus canis is an important opportunistic pathogen of dogs and cats that can also infect a wide range of additional mammals including cows where it can cause mastitis. It is also an emerging human pathogen. Results Here we provide characterization of the first genome sequence for this species, strain FSL S3-227 (milk isolate from a cow with an intra-mammary infection). A diverse array of putative virulence factors was encoded by the S. canis FSL S3-227 genome. Approximately 75% of these gene sequences were homologous to known Streptococcal virulence factors involved in invasion, evasion, and colonization. Present in the genome are multiple potentially mobile genetic elements (MGEs) [plasmid, phage, integrative conjugative element (ICE)] and comparison to other species provided convincing evidence for lateral gene transfer (LGT) between S. canis and two additional bovine mastitis causing pathogens (Streptococcus agalactiae, and Streptococcus dysgalactiae subsp. dysgalactiae), with this transfer possibly contributing to host adaptation. Population structure among isolates obtained from Europe and USA [bovine = 56, canine = 26, and feline = 1] was explored. Ribotyping of all isolates and multi locus sequence typing (MLST) of a subset of the isolates (n = 45) detected significant differentiation between bovine and canine isolates (Fisher exact test: P = 0.0000 [ribotypes], P = 0.0030 [sequence types]), suggesting possible host adaptation of some genotypes. Concurrently, the ancestral clonal complex (54% of isolates) occurred in many tissue types, all hosts, and all geographic locations suggesting the possibility of a wide and diverse niche. Conclusion This study provides evidence highlighting the importance of LGT in the evolution of the bacteria S. canis, specifically, its possible role in host adaptation and acquisition of virulence factors. Furthermore, recent LGT detected between S. canis and human bacteria (Streptococcus urinalis) is cause for concern, as it highlights the possibility for continued acquisition of human virulence factors for this emerging zoonotic pathogen. PMID:23244770

ESTABLISH AND STANDARDIZE METHODOLOGY FOR DETECTION OF WATERBORNE VIRUSES FROM HUMAN SOURCES

EPA Science Inventory

Research is conducted to develop and standardize methods to detect and measure occurrence of human enteric viruses that cause waterborne disease. The viruses of concern include the emerging pathogens--hepatitis E virus and group B rotaviruses. Also of concern are the coxsackiev...

Toscana meningoencephalitis: a comparison to other viral central nervous system infections

PubMed Central

Jaijakul, Siraya; Arias, Cesar A.; Hossein, Monir; Arduino, Roberto C.; Wootton, Susan H.; Hasbun, Rodrigo

2012-01-01

Background Toscana virus (TOSV) is an emerging pathogen causing central nervous system (CNS) infection in Mediterranean countries, mostly during summer season. Objectives To compare the clinical and laboratory characteristics of Toscana CNS infections to the most common viral pathogens seen in the United States. Study Design We performed a case series of patients with 41 TOSV infection and compared the clinical characteristics, laboratory findings, imaging results and clinical outcomes to the most commonly recognized viral causes of meningoencephalitis in the US (enterovirus (n=60), herpes simplex virus (n=48), and west nile virus (n=30) from our multi-center study of patients with aseptic meningoencephalitis syndromes in the Greater Houston area. Results TOSV infection occurs in different age groups compared to enterovirus, HSV, and WNV. All infections most frequently occur during summer-fall except HSV which distributes throughout the year. All patients with TOSV had history of travel to endemic areas. There are differences in clinical presentation and CSF findings comparing TOSV and enterovirus, HSV, and WNV infection. There are no significant differences in outcomes of each infection except WNV meningoencephalitis which had a poorer outcome compared to TOSV infection. Conclusions TOSV is an emerging pathogen that should be considered in the differential diagnosis of patients with CNS infections and a recent travel history to endemic areas. PMID:22867730

Biofilm formation by enteric pathogens and its role in plant colonization and persistence

PubMed Central

Yaron, Sima; Römling, Ute

2014-01-01

The significant increase in foodborne outbreaks caused by contaminated fresh produce, such as alfalfa sprouts, lettuce, melons, tomatoes and spinach, during the last 30 years stimulated investigation of the mechanisms of persistence of human pathogens on plants. Emerging evidence suggests that Salmonella enterica and Escherichia coli, which cause the vast majority of fresh produce outbreaks, are able to adhere to and to form biofilms on plants leading to persistence and resistance to disinfection treatments, which subsequently can cause human infections and major outbreaks. In this review, we present the current knowledge about host, bacterial and environmental factors that affect the attachment to plant tissue and the process of biofilm formation by S. enterica and E. coli, and discuss how biofilm formation assists in persistence of pathogens on the plants. Mechanisms used by S. enterica and E. coli to adhere and persist on abiotic surfaces and mammalian cells are partially similar and also used by plant pathogens and symbionts. For example, amyloid curli fimbriae, part of the extracellular matrix of biofilms, frequently contribute to adherence and are upregulated upon adherence and colonization of plant material. Also the major exopolysaccharide of the biofilm matrix, cellulose, is an adherence factor not only of S. enterica and E. coli, but also of plant symbionts and pathogens. Plants, on the other hand, respond to colonization by enteric pathogens with a variety of defence mechanisms, some of which can effectively inhibit biofilm formation. Consequently, plant compounds might be investigated for promising novel antibiofilm strategies. PMID:25351039

Hydropericardium Hepatitis Syndrome Emerged in Cherry Valley Ducks in China.

PubMed

Chen, H; Dou, Y; Zheng, X; Tang, Y; Zhang, M; Zhang, Y; Wang, Z; Diao, Y

2017-08-01

Since June 2015, a highly pathogenic disease occurred in duck flocks in China, causing pericardial effusion, enlarged discoloured liver, renal enlargement and haemorrhagic lung with a mortality ranging from 5% to 20%. Previous study confirmed that Fowl adenovirus group C (FAdV-C) and some field FAdVs isolates had been identified as causative agents of hydropericardium hepatitis syndrome (HHS) in chickens and geese world widely. In this study, we firstly report the isolation of FAdV-C from ducks with HHS. The two isolates, designated as SDSX and SDJX, were separated from liver samples using 9-day-old SPF chicken embryos and could cause severe cytopathic effects in duck and chicken embryonic kidney cells. The entire ORF sequences of hexon gene of the two isolates were amplified, sequenced and analysed by restriction fragment length polymorphism. Phylogenetic analysis of loop 1 sequences of hexon gene of FAdVs revealed that the two isolates were closely related to FAdV-C isolates, which could cause HHS in chickens. Experimental infection indicated that the isolate was high pathogenicity to 20-day-old ducks. Our study shows that the recently emerged HHS in ducks was caused by FAdV-C and may possess a potential risk to other poultry flocks. © 2016 Blackwell Verlag GmbH.

Encephalitis Surveillance through the Emerging Infections Program, 1997–2010

PubMed Central

Glaser, Carol A.

2015-01-01

Encephalitis is a devastating illness that commonly causes neurologic disability and has a case fatality rate >5% in the United States. An etiologic agent is identified in <50% of cases, making diagnosis challenging. The Centers for Disease Control and Prevention Emerging Infections Program (EIP) Encephalitis Project established syndromic surveillance for encephalitis in New York, California, and Tennessee, with the primary goal of increased identification of causative agents and secondary goals of improvements in treatment and outcome. The project represents the largest cohort of patients with encephalitis studied to date and has influenced case definition and diagnostic evaluation of this condition. Results of this project have provided insight into well-established causal pathogens and identified newer causes of infectious and autoimmune encephalitis. The recognition of a possible relationship between enterovirus D68 and acute flaccid paralysis with myelitis underscores the need for ongoing vigilance for emerging causes of neurologic disease. PMID:26295485

Common and emerging infectious diseases in the animal shelter.

PubMed

Pesavento, P A; Murphy, B G

2014-03-01

The beneficial role that animal shelters play is unquestionable. An estimated 3 to 4 million animals are cared for or placed in homes each year, and most shelters promote public health and support responsible pet ownership. It is, nonetheless, inevitable that shelters are prime examples of anthropogenic biological instability: even well-run shelters often house transient, displaced, and mixed populations of animals. Many of these animals have received minimal to no prior health care, and some have a history of scavenging or predation to survive. Overcrowding and poor shelter conditions further magnify these inherent risks to create individual, intraspecies, and interspecies stress and provide an environment conducive to exposure to numerous potentially collaborative pathogens. All of these factors can contribute to the evolution and emergence of new pathogens or to alterations in virulence of endemic pathogens. While it is not possible to effectively anticipate the timing or the pathogen type in emergence events, their sites of origin are less enigmatic, and pathologists and diagnosticians who work with sheltered animal populations have recognized several such events in the past decade. This article first considers the contribution of the shelter environment to canine and feline disease. This is followed by summaries of recent research on the pathogenesis of common shelter pathogens, as well as research that has led to the discovery of novel or emerging diseases and the methods that are used for their diagnosis and discovery. For the infectious agents that commonly affect sheltered dogs and cats, including canine distemper virus, canine influenza virus, Streptococcus spp, parvoviruses, feline herpesvirus, feline caliciviruses, and feline infectious peritonitis virus, we present familiar as well as newly recognized lesions associated with infection. Preliminary studies on recently discovered viruses like canine circovirus, canine bocavirus, and feline norovirus indicate that these pathogens can cause or contribute to canine and feline disease.

Haemophilus ducreyi: from sexually transmitted infection to skin ulcer pathogen.

PubMed

Lewis, David A; Mitjà, Oriol

2016-02-01

This article provides an overview of the biology, epidemiology, clinical features, diagnostic tests, and treatment of Haemophilus ducreyi infection, with special reference to the decline of chancroid and the recent emergence of H. ducreyi as a pathogen responsible for chronic limb ulceration clinically similar to yaws. Chancroid has declined in importance as a sexually transmitted infection in most countries where it was previously endemic. Chancroid may be caused by either class I or class II H. ducreyi isolates; these two classes diverged from each other approximately 1.95 million years ago. H. ducreyi has recently emerged as a cause of chronic skin ulceration in the Pacific region and Africa. Based on sequencing of whole genomes and defined genetic loci, it appears that the cutaneous H. ducreyi strains diverged from the class I genital strains relatively recently. H. ducreyi should be considered as a major cause of chronic limb ulceration in both adults and children and appropriate molecular diagnostic assays are required to determine ulcer aetiology. The high prevalence of H. ducreyi-related cutaneous ulceration in yaws-endemic countries has challenged the validity of observational surveys to monitor the effectiveness of the WHO's yaws eradication campaign.

Highly Pathogenic Influenza A(H5Nx) Viruses with Altered H5 Receptor-Binding Specificity

PubMed Central

Guo, Hongbo; de Vries, Erik; McBride, Ryan; Dekkers, Jojanneke; Peng, Wenjie; Bouwman, Kim M.; Nycholat, Corwin; Verheije, M. Helene; Paulson, James C.; van Kuppeveld, Frank J.M.

2017-01-01

Emergence and intercontinental spread of highly pathogenic avian influenza A(H5Nx) virus clade 2.3.4.4 is unprecedented. H5N8 and H5N2 viruses have caused major economic losses in the poultry industry in Europe and North America, and lethal human infections with H5N6 virus have occurred in Asia. Knowledge of the evolution of receptor-binding specificity of these viruses, which might affect host range, is urgently needed. We report that emergence of these viruses is accompanied by a change in receptor-binding specificity. In contrast to ancestral clade 2.3.4 H5 proteins, novel clade 2.3.4.4 H5 proteins bind to fucosylated sialosides because of substitutions K222Q and S227R, which are unique for highly pathogenic influenza virus H5 proteins. North American clade 2.3.4.4 virus isolates have retained only the K222Q substitution but still bind fucosylated sialosides. Altered receptor-binding specificity of virus clade 2.3.4.4 H5 proteins might have contributed to emergence and spread of H5Nx viruses. PMID:27869615

Comprehensive bactericidal activity of an ethanol-based hand gel in 15 seconds.

PubMed

Kampf, Günter; Hollingsworth, Angela

2008-01-22

Some studies indicate that the commonly recommended 30 s application time for the post contamination treatment of hands may not be necessary as the same effect may be achieved with some formulations in a shorter application time such as 15 s. We evaluated the bactericidal activity of an ethanol-based hand gel (Sterillium Comfort Gel) within 15 s in a time-kill-test against 11 Gram-positive, 16 Gram-negative bacteria and 11 emerging bacterial pathogens. Each strain was evaluated in quadruplicate. The hand gel (85% ethanol, w/w) was found to reduce all 11 Gram-positive and all 16 Gram-negative bacteria by more than 5 log10 steps within 15 s, not only against the ATCC test strains but also against corresponding clinical isolates. In addition, a log10 reduction > 5 was observed against all tested emerging bacterial pathogens. The ethanol-based hand gel was found to have a broad spectrum of bactericidal activity in only 15 s which includes the most common species causing nosocomial infections and the relevant emerging pathogens. Future research will hopefully help to find out if a shorter application time for the post contamination treatment of hands provides more benefits or more risks.

Emergence of a deviating genotype VI pigeon paramyxovirus type-1 isolated from India.

PubMed

Ganar, Ketan; Das, Moushumee; Raut, Ashwin Ashok; Mishra, Anamika; Kumar, Sachin

2017-07-01

Pigeon paramyxovirus type 1 (PPMV-1) is an antigenic variant of avian paramyxovirus type 1 (APMV-1), which infects pigeons. The virus causes high morbidity and mortality, creating an alarming state for the poultry industry. The present work describes the molecular and pathogenic characterization of a PPMV-1 strain isolated from pigeon in Bhopal, India. Complete genome sequence analysis revealed a genome of 15,192 nucleotides encoding six genes organized in the order 3'-N-P-M-F-HN-L-5'. The fusion gene sequence analysis showed the presence of multiple basic amino acids 112 R-R-Q-K-R-F 117 at the cleavage site corresponding to pathogenic strains. The mean death time and intracerebral pathogenicity index values indicated a mesogenic nature for the PPMV-1 isolate. On phylogenetic analysis, the strain clustered with genotype VI viruses, including isolates from pigeon and dove. The Bhopal strain showed significant intra and inter-genotype evolutionary distance, suggesting the emergence of a new sub-genotype, VIj.

A network-patch methodology for adapting agent-based models for directly transmitted disease to mosquito-borne disease.

PubMed

Manore, Carrie A; Hickmann, Kyle S; Hyman, James M; Foppa, Ivo M; Davis, Justin K; Wesson, Dawn M; Mores, Christopher N

2015-01-01

Mosquito-borne diseases cause significant public health burden and are widely re-emerging or emerging. Understanding, predicting, and mitigating the spread of mosquito-borne disease in diverse populations and geographies are ongoing modelling challenges. We propose a hybrid network-patch model for the spread of mosquito-borne pathogens that accounts for individual movement through mosquito habitats, extending the capabilities of existing agent-based models (ABMs) to include vector-borne diseases. The ABM are coupled with differential equations representing 'clouds' of mosquitoes in patches accounting for mosquito ecology. We adapted an ABM for humans using this method and investigated the importance of heterogeneity in pathogen spread, motivating the utility of models of individual behaviour. We observed that the final epidemic size is greater in patch models with a high risk patch frequently visited than in a homogeneous model. Our hybrid model quantifies the importance of the heterogeneity in the spread of mosquito-borne pathogens, guiding mitigation strategies.

Indicator organisms in meat and poultry slaughter operations: their potential use in process control and the role of emerging technologies.

PubMed

Saini, Parmesh K; Marks, Harry M; Dreyfuss, Moshe S; Evans, Peter; Cook, L Victor; Dessai, Uday

2011-08-01

Measuring commonly occurring, nonpathogenic organisms on poultry products may be used for designing statistical process control systems that could result in reductions of pathogen levels. The extent of pathogen level reduction that could be obtained from actions resulting from monitoring these measurements over time depends upon the degree of understanding cause-effect relationships between processing variables, selected output variables, and pathogens. For such measurements to be effective for controlling or improving processing to some capability level within the statistical process control context, sufficiently frequent measurements would be needed to help identify processing deficiencies. Ultimately the correct balance of sampling and resources is determined by those characteristics of deficient processing that are important to identify. We recommend strategies that emphasize flexibility, depending upon sampling objectives. Coupling the measurement of levels of indicator organisms with practical emerging technologies and suitable on-site platforms that decrease the time between sample collections and interpreting results would enhance monitoring process control.

Search strategy has influenced the discovery rate of human viruses.

PubMed

Rosenberg, Ronald; Johansson, Michael A; Powers, Ann M; Miller, Barry R

2013-08-20

A widely held concern is that the pace of infectious disease emergence has been increasing. We have analyzed the rate of discovery of pathogenic viruses, the preeminent source of newly discovered causes of human disease, from 1897 through 2010. The rate was highest during 1950-1969, after which it moderated. This general picture masks two distinct trends: for arthropod-borne viruses, which comprised 39% of pathogenic viruses, the discovery rate peaked at three per year during 1960-1969, but subsequently fell nearly to zero by 1980; however, the rate of discovery of nonarboviruses remained stable at about two per year from 1950 through 2010. The period of highest arbovirus discovery coincided with a comprehensive program supported by The Rockefeller Foundation of isolating viruses from humans, animals, and arthropod vectors at field stations in Latin America, Africa, and India. The productivity of this strategy illustrates the importance of location, approach, long-term commitment, and sponsorship in the discovery of emerging pathogens.

Fever in immunocompromised hosts.

PubMed

Patel, Devang M; Riedel, David J

2013-11-01

Fever is one of the most common reasons for the emergency department presentation of immunocompromised patients. Their differential diagnosis can be broad and includes rare or unexpected pathogens. Certain infectious causes of fever portend true emergencies; if they are not managed appropriately, rapid progression and death may ensue. This article reviews the diagnosis and management of fevers in patients immunocompromised by human immunodeficiency virus/AIDS, solid-organ and hematopoietic transplants, chemotherapy-induced neutropenia, and tumor necrosis factor-α inhibitors. Prompt recognition of the type of immunosuppression and delineation of possible causes of fever are critical for management of these complex patients. Copyright © 2013 Elsevier Inc. All rights reserved.

A New Threat to Honey Bees, the Parasitic Phorid Fly Apocephalus borealis

PubMed Central

Core, Andrew; Runckel, Charles; Ivers, Jonathan; Quock, Christopher; Siapno, Travis; DeNault, Seraphina; Brown, Brian; DeRisi, Joseph; Smith, Christopher D.; Hafernik, John

2012-01-01

Honey bee colonies are subject to numerous pathogens and parasites. Interaction among multiple pathogens and parasites is the proposed cause for Colony Collapse Disorder (CCD), a syndrome characterized by worker bees abandoning their hive. Here we provide the first documentation that the phorid fly Apocephalus borealis, previously known to parasitize bumble bees, also infects and eventually kills honey bees and may pose an emerging threat to North American apiculture. Parasitized honey bees show hive abandonment behavior, leaving their hives at night and dying shortly thereafter. On average, seven days later up to 13 phorid larvae emerge from each dead bee and pupate away from the bee. Using DNA barcoding, we confirmed that phorids that emerged from honey bees and bumble bees were the same species. Microarray analyses of honey bees from infected hives revealed that these bees are often infected with deformed wing virus and Nosema ceranae. Larvae and adult phorids also tested positive for these pathogens, implicating the fly as a potential vector or reservoir of these honey bee pathogens. Phorid parasitism may affect hive viability since 77% of sites sampled in the San Francisco Bay Area were infected by the fly and microarray analyses detected phorids in commercial hives in South Dakota and California's Central Valley. Understanding details of phorid infection may shed light on similar hive abandonment behaviors seen in CCD. PMID:22235317

Starting from the bench--prevention and control of foodborne and zoonotic diseases.

PubMed

Vongkamjan, Kitiya; Wiedmann, Martin

2015-02-01

Foodborne diseases are estimated to cause around 50 million disease cases and 3000 deaths a year in the US. Worldwide, food and waterborne diseases are estimated to cause more than 2 million deaths per year. Lab-based research is a key component of efforts to prevent and control foodborne diseases. Over the last two decades, molecular characterization of pathogen isolates has emerged as a key component of foodborne and zoonotic disease prevention and control. Characterization methods have evolved from banding pattern-based subtyping methods to sequenced-based approaches, including full genome sequencing. Molecular subtyping methods not only play a key role for characterizing pathogen transmission and detection of disease outbreaks, but also allow for identification of clonal pathogen groups that show distinct transmission characteristics. Importantly, the data generated from molecular characterization of foodborne pathogens also represent critical inputs for epidemiological and modeling studies. Continued and enhanced collaborations between infectious disease related laboratory sciences and epidemiologists, modelers, and other quantitative scientists will be critical to a One-Health approach that delivers societal benefits, including improved surveillance systems and prevention approaches for zoonotic and foodborne pathogens. Copyright © 2014 Elsevier B.V. All rights reserved.

EMERGING PATHOGENS OF ANIMAL ORIGIN: UNIQUE CHALLENGES FOR QUANTITATIVE MICROBIAL RISK ASSESSMENT

EPA Science Inventory

Recently severe human epidemics caused by waterborne Cryptosporidium parvum and Escherichia coli Strain (157:H7 of animal origin have attracted much attention in the national news media. Among the 130 diseases that can be transmitted to man from domestic and wild animals, a signi...

Characterization of resistance to powdery mildew in the Hop cultivars Newport and Comet

USDA-ARS?s Scientific Manuscript database

Hop powdery mildew, caused by Podosphaera macularis, is an important disease in the Northwestern U.S. Outbreaks of powdery mildew on cultivars previously resistant to the disease have been reported increasingly with the emergence of virulent pathogen strains capable of overcoming a commonly deployed...

Regulation of flagellum biosynthesis within the fish pathogen Yersinia ruckeri

USDA-ARS?s Scientific Manuscript database

Yersinia ruckeri, a Gram negative Enterobacterium, is the causative agent of enteric red mouth disease (ERM) within farmed rainbow trout (Oncorhynchus mykiss, Walbaum). There has been an increase of ERM outbreaks in previously vaccinated trout caused by a recently emerged, non-motile variant of Y. r...

Domestic goose model for West Nile virus vaccine efficiency testing

USDA-ARS?s Scientific Manuscript database

West Nile virus (WNV) is an emergent pathogen in the Americas, first reported in New York during 1999, and has since spread across the United States (USA), Central and South America causing neurological disease in humans, horses and some bird species, including domestic geese. No WNV vaccines are li...

Editorial: Emerging approaches for typing, detection, characterization, and traceback of Escherichia coli

USDA-ARS?s Scientific Manuscript database

Commensal E. coli inhabit the large intestines of humans and animals and are important in maintaining normal intestinal homeostasis. There are also many groups of disease-causing E. coli, including diarrheagenic and extra-intestinal pathogenic E. coli (ExPEC). There are approximately O188 somatic O...

Contributions of hydrology to Vesicular Stomatitis Virus emergence in the Western United States

USDA-ARS?s Scientific Manuscript database

Relationships between environmental variables associated with the spread of vector-borne pathogens, such as RNA viruses transmitted to humans and animals, remain poorly understood. Vesicular stomatitis (VS) is caused by a vector-borne, zoonotic RNA virus (VSV), and is the most common vesicular dise...

Pathogenicity and Molecular Characterization of Emerging Porcine Reproductive and Respiratory Syndrome Virus in Vietnam in 2007

USDA-ARS?s Scientific Manuscript database

In 2007, Vietnam experienced swine disease outbreaks causing clinical signs similar to the "porcine high fever disease" that occurred in China during 2006. Analysis of diagnostic samples from the disease outbreaks in Vietnam identified porcine reproductive and respiratory syndrome virus (PRRSV) and ...

What lies beneath, unraveling the mysteries of Rhizoctonia and Pythium

USDA-ARS?s Scientific Manuscript database

Washington wheat and barley growers have long recognized that the soil-borne fungal pathogens Rhizoctonia and Pythium cause root rot, stunting and poor emergence and can chip away at yield, resulting in annual losses of 10 percent or more. Since several of these Rhizoctonia and Pythium species attac...

Multiplex surface plasmon resonance imaging platform for label-free detection of foodborne pathogens

USDA-ARS?s Scientific Manuscript database

Salmonellae are among the leading causes of foodborne outbreaks in the United States, and more rapid and efficient detection methods are needed. Surface plasmon resonance imaging (SPRi) is an emerging optical technique, which allows for rapid and label-free screening of multiple targets simultaneous...

DEVELOPMENT OF A MOLECULAR METHOD TO IDENTIFY HEPATITIS E VIRUS

EPA Science Inventory

Hepatitis E virus (HEV) is a waterborne emerging pathogen that causes significant illness in the developing world. Thus far, an HEV outbreak has not been reported in the U.S., although a swine variant of the virus is common in Midwestern hogs. Because viruses isolated from two ...

In silico identification of molecular mimics involved in the pathogenesis of Clostridium botulinum ATCC 3502 strain.

PubMed

Bhardwaj, Tulika; Haque, Shafiul; Somvanshi, Pallavi

2018-05-12

Bacterial pathogens invade and disrupt the host defense system by means of protein sequences structurally similar at global and local level both. The sharing of homologous sequences between the host and the pathogenic bacteria mediates the infection and defines the concept of molecular mimicry. In this study, various computational approaches were employed to elucidate the pathogenicity of Clostridium botulinum ATCC 3502 at genome-wide level. Genome-wide study revealed that the pathogen mimics the host (Homo sapiens) and unraveled the complex pathogenic pathway of causing infection. The comparative 'omics' approaches helped in selective screening of 'molecular mimicry' candidates followed by the qualitative assessment of the virulence potential and functional enrichment. Overall, this study provides a deep insight into the emergence and surveillance of multidrug resistant C. botulinum ATCC 3502 caused infections. This is the very first report identifying C. botulinum ATCC 3502 proteome enriched similarities to the human host proteins and resulted in the identification of 20 potential mimicry candidates, which were further characterized qualitatively by sub-cellular organization prediction and functional annotation. This study will provide a variety of avenues for future studies related to infectious agents, host-pathogen interactions and the evolution of pathogenesis process. Copyright © 2018. Published by Elsevier Ltd.

Aspergillus sydowii and Other Potential Fungal Pathogens in Gorgonian Octocorals of the Ecuadorian Pacific.

PubMed

Soler-Hurtado, M Mar; Sandoval-Sierra, José Vladimir; Machordom, Annie; Diéguez-Uribeondo, Javier

2016-01-01

Emerging fungal diseases are threatening ecosystems and have increased in recent decades. In corals, the prevalence and consequences of these infections have also increased in frequency and severity. Coral reefs are affected by an emerging fungal disease named aspergillosis, caused by Aspergillus sydowii. This disease and its pathogen have been reported along the Caribbean and Pacific coasts of Colombia. Despite this, an important number of coral reefs worldwide have not been investigated for the presence of this pathogen. In this work, we carried out the surveillance of the main coral reef of the Ecuadorian Pacific with a focus on the two most abundant and cosmopolitan species of this ecosystem, Leptogorgia sp. and Leptogorgia obscura. We collected 59 isolates and obtained the corresponding sequences of the Internal Transcribed Spacers (ITS) of the ribosomal DNA. These were phylogenetically analyzed using MrBayes, which indicated the presence of two isolates of the coral reef pathogen A. sydowii, as well as 16 additional species that are potentially pathogenic to corals. Although the analyzed gorgonian specimens appeared healthy, the presence of these pathogens, especially of A. sydowii, alert us to the potential risk to the health and future survival of the Pacific Ecuadorian coral ecosystem under the current scenario of increasing threats and stressors to coral reefs, such as habitat alterations by humans and global climate change.

Quantifying known and emerging uterine pathogens, and evaluating their association with metritis and fever in dairy cows.

PubMed

Cunha, Federico; Jeon, Soo Jin; Daetz, Rodolfo; Vieira-Neto, Achilles; Laporta, Jimena; Jeong, K Casey; Barbet, Anthony F; Risco, Carlos A; Galvão, Klibs N

2018-07-01

Metritis is caused by polymicrobial infection; however, recent metagenomic work challenges the importance of known pathogens such as Escherichia coli and Trueperella pyogenes while identifying potential new pathogens such as Bacteroides pyogenes, Porphyromonas levii and Helcococcus ovis. This study aims to quantify known and emerging uterine pathogens, and to evaluate their association with metritis and fever in dairy cows. Metritis was diagnosed at 6 ± 2 days postpartum, a uterine swab was collected and rectal temperature was measured. 39 cows were classified into three groups: Healthy (n = 14), Metritis without fever (MNoFever; n = 12), and Metritis with fever (MFever; n = 13). Absolute copy number was determined for total bacteria and for 8 potentially pathogenic bacteria using droplet digital PCR. Both MNoFever and MFever cows had higher copy number of total bacteria, Fusobacterium necrophorum, Prevotella melaninogenica, Bacteroides pyogenes, Porphyromonas levii, and Helcococcus ovis than Healthy cows. MNoFever and MFever groups were similar. There was no difference among groups in copy number of Escherichia coli, Trueperella pyogenes, and Bacteroides heparinolyticus, and they all had low copy numbers. Our work confirms the importance of some bacteria identified by culture-based studies in the pathogenesis of metritis such as Fusobacterium necrophorum and Prevotella melaninogenica; however, it challenges the importance of others such as Escherichia coli and Trueperella pyogenes at the time of metritis diagnosis. Additionally, Bacteroides pyogenes, Porphyromonas levii, and Helcococcus ovis were recognized as emerging pathogens involved in the etiology of metritis. Furthermore, fever was not associated with the total bacterial load or specific bacteria. Copyright © 2018 Elsevier Inc. All rights reserved.

Genome-Wide Analysis of Secondary Metabolite Gene Clusters in Ophiostoma ulmi and Ophiostoma novo-ulmi Reveals a Fujikurin-Like Gene Cluster with a Putative Role in Infection.

PubMed

Sbaraini, Nicolau; Andreis, Fábio C; Thompson, Claudia E; Guedes, Rafael L M; Junges, Ângela; Campos, Thais; Staats, Charley C; Vainstein, Marilene H; Ribeiro de Vasconcelos, Ana T; Schrank, Augusto

2017-01-01

The emergence of new microbial pathogens can result in destructive outbreaks, since their hosts have limited resistance and pathogens may be excessively aggressive. Described as the major ecological incident of the twentieth century, Dutch elm disease, caused by ascomycete fungi from the Ophiostoma genus, has caused a significant decline in elm tree populations ( Ulmus sp.) in North America and Europe. Genome sequencing of the two main causative agents of Dutch elm disease ( Ophiostoma ulmi and Ophiostoma novo-ulmi ), along with closely related species with different lifestyles, allows for unique comparisons to be made to identify how pathogens and virulence determinants have emerged. Among several established virulence determinants, secondary metabolites (SMs) have been suggested to play significant roles during phytopathogen infection. Interestingly, the secondary metabolism of Dutch elm pathogens remains almost unexplored, and little is known about how SM biosynthetic genes are organized in these species. To better understand the metabolic potential of O. ulmi and O. novo-ulmi , we performed a deep survey and description of SM biosynthetic gene clusters (BGCs) in these species and assessed their conservation among eight species from the Ophiostomataceae family. Among 19 identified BGCs, a fujikurin-like gene cluster (OpPKS8) was unique to Dutch elm pathogens. Phylogenetic analysis revealed that orthologs for this gene cluster are widespread among phytopathogens and plant-associated fungi, suggesting that OpPKS8 may have been horizontally acquired by the Ophiostoma genus. Moreover, the detailed identification of several BGCs paves the way for future in-depth research and supports the potential impact of secondary metabolism on Ophiostoma genus' lifestyle.

Current and emerging techniques for antibiotic susceptibility tests.

PubMed

Syal, Karan; Mo, Manni; Yu, Hui; Iriya, Rafael; Jing, Wenwen; Guodong, Sui; Wang, Shaopeng; Grys, Thomas E; Haydel, Shelley E; Tao, Nongjian

2017-01-01

Infectious diseases caused by bacterial pathogens are a worldwide burden. Serious bacterial infection-related complications, such as sepsis, affect over a million people every year with mortality rates ranging from 30% to 50%. Crucial clinical microbiology laboratory responsibilities associated with patient management and treatment include isolating and identifying the causative bacterium and performing antibiotic susceptibility tests (ASTs), which are labor-intensive, complex, imprecise, and slow (taking days, depending on the growth rate of the pathogen). Considering the life-threatening condition of a septic patient and the increasing prevalence of antibiotic-resistant bacteria in hospitals, rapid and automated diagnostic tools are needed. This review summarizes the existing commercial AST methods and discusses some of the promising emerging AST tools that will empower humans to win the evolutionary war between microbial genes and human wits.

Genomic dissection of host-microbe and microbe-microbe interactions for advanced plant breeding.

PubMed

Kroll, Samuel; Agler, Matthew T; Kemen, Eric

2017-04-01

Agriculture faces many emerging challenges to sustainability, including limited nutrient resources, losses from diseases caused by current and emerging pathogens and environmental degradation. Microorganisms have great importance for plant growth and performance, including the potential to increase yields, nutrient uptake and pathogen resistance. An urgent need is therefore to understand and engineer plants and their associated microbial communities. Recent massive genomic sequencing of host plants and associated microbes offers resources to identify novel mechanisms of communal assembly mediated by the host. For example, host-microbe and microbe-microbe interactions are involved in niche formation, thereby contributing to colonization. By leveraging genomic resources, genetic traits underlying those mechanisms will become important resources to design plants selecting and hosting beneficial microbial communities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Current and emerging techniques for antibiotic susceptibility tests

PubMed Central

Syal, Karan; Mo, Manni; Yu, Hui; Iriya, Rafael; Jing, Wenwen; Guodong, Sui; Wang, Shaopeng; Grys, Thomas E.; Haydel, Shelley E.; Tao, Nongjian

2017-01-01

Infectious diseases caused by bacterial pathogens are a worldwide burden. Serious bacterial infection-related complications, such as sepsis, affect over a million people every year with mortality rates ranging from 30% to 50%. Crucial clinical microbiology laboratory responsibilities associated with patient management and treatment include isolating and identifying the causative bacterium and performing antibiotic susceptibility tests (ASTs), which are labor-intensive, complex, imprecise, and slow (taking days, depending on the growth rate of the pathogen). Considering the life-threatening condition of a septic patient and the increasing prevalence of antibiotic-resistant bacteria in hospitals, rapid and automated diagnostic tools are needed. This review summarizes the existing commercial AST methods and discusses some of the promising emerging AST tools that will empower humans to win the evolutionary war between microbial genes and human wits. PMID:28638468

Forthcoming therapeutic perspectives for infections due to multidrug-resistant Gram-positive pathogens.

PubMed

Cornaglia, G; Rossolini, G M

2009-03-01

Multidrug resistance in Gram-positive pathogens emerged as a major therapeutic challenge over two decades ago. The worldwide spread of methicillin-resistant Staphylococcus aureus (MRSA), glycopeptide-resistant enterococci and other resistant Gram-positive pathogens had a major impact on antibiotic policies, and prompted the discovery and development of new antibiotics to combat difficult-to-treat infections caused by such pathogens. Several new antibiotics active against multidrug-resistant Gram-positive pathogens have recently been introduced into clinical practice, and the antibiotic pipeline contains additional anti-Gram-positive drugs at an advanced stage of development, including new glycopeptides (dalbavancin, oritavancin, and telavancin), new anti-MRSA beta-lactams (ceftobiprole), and new diaminopyrimidines (iclaprim). This article provides a brief overview of these upcoming agents, partially based on the material presented at the ESCMID Conference entitled 'Fighting infections due to multidrug-resistant Gram-positives' (Venice, Italy, 29-31 May 2008) and on the most recent literature.

Bradford Hill's criteria, emerging zoonoses, and One Health.

PubMed

Asokan, G V; Asokan, Vanitha

2016-09-01

Zoonoses constitute more than 60% of infectious diseases and 75% of emerging infectious diseases. Inappropriate overemphasis of specialization of disciplines has ignored public health. Identifying the causes of disease and determining how exposures are related to outcomes in "emerging zoonoses" affecting multiple species are considered to be the hallmarks of public health research and practice that compels the adoption of "One Health". The interactions within and among populations of vertebrates in the causation and transmissions of emerging zoonotic diseases are inherently dynamic, interdependent, and systems based. Disease causality theories have moved from one or several agents causing disease in a single species, to one infectious agent causing disease in multiple species-emerging zoonoses. Identification of the causative pathogen components or structures, elucidating the mechanisms of species specificity, and understanding the natural conditions of emergence would facilitate better derivation of the causal mechanism. Good quality evidence on causation in emerging zoonoses affecting multiple species makes a strong recommendation under the One Health approach for disease prevention and control from diagnostic tests, treatment, antimicrobial resistance, preventive vaccines, and evidence informed health policies. In the tenets of One Health, alliances work best when the legitimate interests of the different partners combine to prevent and control emerging zoonoses. Copyright © 2015 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.

Infection strategies of enteric pathogenic Escherichia coli

PubMed Central

Clements, Abigail; Young, Joanna C.; Constantinou, Nicholas; Frankel, Gad

2012-01-01

Enteric Escherichia coli (E. coli) are both natural flora of humans and important pathogens causing significant morbidity and mortality worldwide. Traditionally enteric E. coli have been divided into 6 pathotypes, with further pathotypes often proposed. In this review we suggest expansion of the enteric E. coli into 8 pathotypes to include the emerging pathotypes of adherent invasive E. coli (AIEC) and Shiga-toxin producing enteroaggregative E. coli (STEAEC). The molecular mechanisms that allow enteric E. coli to colonize and cause disease in the human host are examined and for two of the pathotypes that express a type 3 secretion system (T3SS) we discuss the complex interplay between translocated effectors and manipulation of host cell signaling pathways that occurs during infection. PMID:22555463

Approach to common bacterial infections: community-acquired pneumonia.

PubMed

Iroh Tam, Pui-Ying

2013-04-01

Community-acquired pneumonia (CAP) occurs more often in early childhood than at almost any other age. Many microorganisms are associated with pneumonia, but individual pathogens are difficult to identify, which poses problems in antibiotic management. This article reviews the common as well as new, emerging pathogens, as well as the guidelines for management of pediatric CAP. Current guidelines for pediatric CAP continue to recommend the use of high-dose amoxicillin for bacterial CAP and azithromycin for suspected atypical CAP (usually caused by Mycoplasma pneumoniae) in children. Copyright © 2013 Elsevier Inc. All rights reserved.

Human and Avian Extraintestinal Pathogenic Escherichia coli: Infections, Zoonotic Risks, and Antibiotic Resistance Trends

PubMed Central

2013-01-01

Abstract Extraintestinal pathogenic Escherichia coli (ExPEC) constitutes ongoing health concerns for women, newborns, elderly, and immunocompromised individuals due to increased numbers of urinary tract infections (UTIs), newborn meningitis, abdominal sepsis, and septicemia. E. coli remains the leading cause of UTIs, with recent investigations reporting the emergence of E. coli as the predominant cause of nosocomial and neonatal sepsis infections. This shift from the traditional Gram-positive bacterial causes of nosocomial and neonatal sepsis infections could be attributed to the use of intrapartum chemoprophylaxis against Gram-positive bacteria and the appearance of antibiotic (ATB) resistance in E. coli. While ExPEC strains cause significant healthcare concerns, these bacteria also infect chickens and cause the poultry industry economic losses due to costs of containment, mortality, and disposal of carcasses. To circumvent ExPEC-related costs, ATBs are commonly used in the poultry industry to prevent/treat microbial infections and promote growth and performance. In an unfortunate linkage, chicken products are suspected to be a source of foodborne ExPEC infections and ATB resistance in humans. Therefore, the emergence of multidrug resistance (MDR) (resistance to three or more classes of antimicrobial agents) among avian E. coli has created major economic and health concerns, affecting both human healthcare and poultry industries. Increased numbers of immunocompromised individuals, including the elderly, coupled with MDR among ExPEC strains, will continue to challenge the treatment of ExPEC infections and likely lead to increased treatment costs. With ongoing complications due to emerging ATB resistance, novel treatment strategies are necessary to control ExPEC infections. Recognizing and treating the zoonotic risk posed by ExPEC would greatly enhance food safety and positively impact human health. PMID:23962019

The genome sequence of the emerging common midwife toad virus identifies an evolutionary intermediate within ranaviruses.

PubMed

Mavian, Carla; López-Bueno, Alberto; Balseiro, Ana; Casais, Rosa; Alcamí, Antonio; Alejo, Alí

2012-04-01

Worldwide amphibian population declines have been ascribed to global warming, increasing pollution levels, and other factors directly related to human activities. These factors may additionally be favoring the emergence of novel pathogens. In this report, we have determined the complete genome sequence of the emerging common midwife toad ranavirus (CMTV), which has caused fatal disease in several amphibian species across Europe. Phylogenetic and gene content analyses of the first complete genomic sequence from a ranavirus isolated in Europe show that CMTV is an amphibian-like ranavirus (ALRV). However, the CMTV genome structure is novel and represents an intermediate evolutionary stage between the two previously described ALRV groups. We find that CMTV clusters with several other ranaviruses isolated from different hosts and locations which might also be included in this novel ranavirus group. This work sheds light on the phylogenetic relationships within this complex group of emerging, disease-causing viruses.

Myxomatosis in Australia and Europe: a model for emerging infectious diseases.

PubMed

Kerr, Peter J

2012-03-01

Myxoma virus is a poxvirus naturally found in two American leporid (rabbit) species (Sylvilagus brasiliensis and Sylvilagus bachmani) in which it causes an innocuous localised cutaneous fibroma. However, in European rabbits (Oryctolagus cuniculus) the same virus causes the lethal disseminated disease myxomatosis. The introduction of myxoma virus into the European rabbit population in Australia in 1950 initiated the best known example of what happens when a novel pathogen jumps into a completely naïve new mammalian host species. The short generation time of the rabbit and their vast numbers in Australia meant evolution could be studied in real time. The carefully documented emergence of attenuated strains of virus that were more effectively transmitted by the mosquito vector and the subsequent selection of rabbits with genetic resistance to myxomatosis is the paradigm for pathogen virulence and host-pathogen coevolution. This natural experiment was repeated with the release of a separate strain of myxoma virus in France in 1952. The subsequent spread of the virus throughout Europe and its coevolution with the rabbit essentially paralleled what occurred in Australia. Detailed molecular studies on myxoma virus have dissected the role of virulence genes in the pathogenesis of myxomatosis and when combined with genomic data and reverse genetics should in future enable the understanding of the molecular evolution of the virus as it adapted to its new host. This review describes the natural history and evolution of myxoma virus together with the molecular biology and experimental pathogenesis studies that are informing our understanding of evolution of emerging diseases. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Antibiotic therapy of community respiratory tract infections: strategies for optimal outcomes and minimized resistance emergence.

PubMed

Ball, P; Baquero, F; Cars, O; File, T; Garau, J; Klugman, K; Low, D E; Rubinstein, E; Wise, R

2002-01-01

Widespread, increasing antibiotic resistance amongst the major respiratory pathogens has compromised traditional therapy of the major infective respiratory syndromes, including bacterial pneumonia and acute exacerbations of chronic bronchitis. Guidelines for antibiotic prescribing dating from the 1980s to 1990s, which attempted to address such problems, were commonly too prescriptive and difficult to apply, and took little account of end-user practice or locally prevalent resistance levels. Further confusion was caused by conflicting recommendations emanating from differing specialty groups. The evidence that such guidelines benefited either clinical outcomes or treatment costs has been disputed. They have probably had little effect on resistance emergence. We report the recommendations of an independent, multi-national, inter-disciplinary group, which met to identify principles underlying prescribing and guideline formulation in an age of increasing bacterial resistance. Unnecessary prescribing was recognized as the major factor in influencing resistance and costs. Antibiotic therapy must be limited to syndromes in which bacterial infection is the predominant cause and should attempt maximal reduction in bacterial load, with the ultimate aim of bacterial eradication. It should be appropriate in type and context of local resistance prevalence, and optimal in dosage for the pathogen(s) involved. Prescribing should be based on pharmacodynamic principles that predict efficacy, bacterial eradication and prevention of resistance emergence. Pharmacoeconomic analyses confirm that bacteriologically more effective antibiotics can reduce overall management costs, particularly with respect to consequential morbidity and hospital admission. Application of these principles should positively benefit therapeutic outcomes, resistance avoidance and management costs and will more accurately guide antibiotic choices by both individuals and formulary/guideline committees.

Shiga toxin-converting phages and the emergence of new pathogenic Escherichia coli: a world in motion

PubMed Central

Tozzoli, Rosangela; Grande, Laura; Michelacci, Valeria; Ranieri, Paola; Maugliani, Antonella; Caprioli, Alfredo; Morabito, Stefano

2014-01-01

Shiga toxin (Stx)-producing Escherichia coli (STEC) are pathogenic E. coli causing diarrhea, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). STEC are characterized by a constellation of virulence factors additional to Stx and have long been regarded as capable to cause HC and HUS when possessing the ability of inducing the attaching and effacing (A/E) lesion to the enterocyte, although strains isolated from such severe infections sometimes lack this virulence feature. Interestingly, the capability to cause the A/E lesion is shared with another E. coli pathogroup, the Enteropathogenic E. coli (EPEC). In the very recent times, a different type of STEC broke the scene causing a shift in the paradigm for HUS-associated STEC. In 2011, a STEC O104:H4 caused a large outbreak with more than 800 HUS and 50 deaths. Such a strain presented the adhesion determinants of Enteroaggregative E. coli (EAggEC). We investigated the possibility that, besides STEC and EAggEC, other pathogenic E. coli could be susceptible to infection with stx-phages. A panel of stx2-phages obtained from STEC isolated from human disease was used to infect experimentally E. coli strains representing all the known pathogenic types, including both diarrheagenic E. coli (DEC) and extra-intestinal pathogenic E. coli (ExPEC). We observed that all the E. coli pathogroups used in the infection experiments were susceptible to the infection. Our results suggest that the stx2-phages used may not have specificity for E. coli adapted to the intestinal environment, at least in the conditions used. Additionally, we could only observe transient lysogens suggesting that the event of stable stx2-phage acquisition occurs rarely. PMID:24999453

Linking environmental nutrient enrichment and disease emergence in humans and wildlife

PubMed Central

Johnson, Pieter T. J.; Townsend, Alan R.; Cleveland, Cory C.; Glibert, Patricia M.; Howarth, Robert W.; McKenzie, Valerie J.; Rejmankova, Eliska; Ward, Mary H.

2009-01-01

Worldwide increases in the numbers of human and wildlife diseases present ecologists with the challenge of understanding how large-scale environmental changes affect host-parasite interactions. One of the most profound changes to Earth’s ecosystems is the alteration of global nutrient cycles, including those of phosphorus (P) and especially nitrogen (N). Alongside the obvious direct benefits of nutrient application for food production, growing evidence suggests that anthropogenic inputs of N and P can indirectly affect the abundance of infectious and noninfectious pathogens, sometimes leading to epidemic conditions. However, the mechanisms underpinning observed correlations, and how such patterns vary with disease type, have long remained conjectural. Here, we discuss recent experimental advances in this area to critically evaluate the relationship between environmental nutrient enrichment and disease. Given the inter-related nature of human and wildlife disease emergence, we include a broad range of human and wildlife examples from terrestrial, marine and freshwater ecosystems. We examine the consequences of nutrient pollution on directly transmitted, vector-borne, complex life cycle, and noninfectious pathogens, including West Nile virus, malaria, harmful algal blooms, coral reef diseases and amphibian malformations. Our synthetic examination suggests that the effects of environmental nutrient enrichment on disease are complex and multifaceted, varying with the type of pathogen, host species and condition, attributes of the ecosystem and the degree of enrichment; some pathogens increase in abundance whereas others decline or disappear. Nevertheless, available evidence indicates that ecological changes associated with nutrient enrichment often exacerbate infection and disease caused by generalist parasites with direct or simple life cycles. Observed mechanisms include changes in host/vector density, host distribution, infection resistance, pathogen virulence or toxicity, or the direct supplementation of pathogens. Collectively, these pathogens may be particularly dangerous because they can continue to cause mortality even as their hosts decline, potentially leading to sustained epidemics or chronic pathology. We suggest that interactions between nutrient enrichment and disease will become increasingly important in tropical and subtropical regions, where forecasted increases in nutrient application will occur in an environment rich with infectious pathogens. We emphasize the importance of careful disease management in conjunction with continued intensification of global nutrient cycles. PMID:20349828

Potential impact of climate change on emerging vector-borne and other infections in the UK.

PubMed

Baylis, Matthew

2017-12-05

Climate is one of several causes of disease emergence. Although half or more of infectious diseases are affected by climate it appears to be a relatively infrequent cause of human disease emergence. Climate mostly affects diseases caused by pathogens that spend part of their lifecycle outside of the host, exposed to the environment. The most important routes of transmission of climate sensitive diseases are by arthropod (insect and tick) vectors, in water and in food. Given the sensitivity of many diseases to climate, it is very likely that at least some will respond to future climate change. In the case of vector-borne diseases this response will include spread to new areas. Several vector-borne diseases have emerged in Europe in recent years; these include vivax malaria, West Nile fever, dengue fever, Chikungunya fever, leishmaniasis, Lyme disease and tick-borne encephalitis. The vectors of these diseases are mosquitoes, sand flies and ticks. The UK has endemic mosquito species capable of transmitting malaria and probably other pathogens, and ticks that transmit Lyme disease. The UK is also threatened by invasive mosquito species known to be able to transmit West Nile, dengue, chikungunya and Zika, and sand flies that spread leishmaniasis. Warmer temperatures in the future will increase the suitability of the UK's climate for these invasive species, and increase the risk that they may spread disease. While much attention is on invasive species, it is important to recognize the threat presented by native species too. Proposed actions to reduce the future impact of emerging vector-borne diseases in the UK include insect control activity at points of entry of vehicles and certain goods, wider surveillance for mosquitoes and sand flies, research into the threat posed by native species, increased awareness of the medical profession of the threat posed by specific diseases, regular risk assessments, and increased preparedness for the occurrence of a disease emergency.

Vectors of rickettsiae in Africa.

PubMed

Bitam, Idir

2012-12-01

Vector-borne diseases are caused by parasites, bacteria, or viruses transmitted by the bites of hematophagous arthropods. In Africa, there has been a recent emergence of new diseases and the re-emergence of existing diseases, usually with changes in disease epidemiology (e.g., geographical distribution, prevalence, and pathogenicity). In Africa, rickettsioses are recognized as important emerging vector-borne infections in humans. Rickettsial diseases are transmitted by different types of arthropods, ticks, fleas, lice, and mites. This review will examine the roles of these different arthropod vectors and their geographical distributions. Copyright © 2012 Elsevier GmbH. All rights reserved.

Respiratory Diseases among U.S. Military Personnel: Countering Emerging Threats

PubMed Central

Callahan, Johnny D.; Hawksworth, Anthony W.; Fisher, Carol A.; Gaydos, Joel C.

1999-01-01

Emerging respiratory disease agents, increased antibiotic resistance, and the loss of effective vaccines threaten to increase the incidence of respiratory disease in military personnel. We examine six respiratory pathogens (adenoviruses, influenza viruses, Streptococcus pneumoniae, Streptococcus pyogenes, Mycoplasma pneumoniae, and Bordetella pertussis) and review the impact of the diseases they cause, past efforts to control these diseases in U.S. military personnel, as well as current treatment and surveillance strategies, limitations in diagnostic testing, and vaccine needs. PMID:10341174

Zika Virus as an Emerging Neuropathogen: Mechanisms of Neurovirulence and Neuro-Immune Interactions.

PubMed

Morris, Gerwyn; Barichello, Tatiana; Stubbs, Brendon; Köhler, Cristiano A; Carvalho, André F; Maes, Michael

2018-05-01

Zika virus (ZIKV) is an emerging arbovirus of the genus Flaviviridae, which causes a febrile illness and has spread from across the Pacific to the Americas in a short timeframe. Convincing evidence has implicated the ZIKV to incident cases of neonatal microcephaly and a set of neurodevelopmental abnormalities referred to as the congenital Zika virus syndrome. In addition, emerging data points to an association with the ZIKV and the development of the so-called Guillain-Barre syndrome, an acute autoimmune polyneuropathy. Accumulating knowledge suggests that neurovirulent strains of the ZIKV have evolved from less pathogenic lineages of the virus. Nevertheless, mechanisms of neurovirulence and host-pathogen neuro-immune interactions remain incompletely elucidated. This review provides a critical discussion of genetic and structural alterations in the ZIKV which could have contributed to the emergence of neurovirulent strains. In addition, a mechanistic framework of neuro-immune mechanisms related to the emergence of neuropathology after ZIKV infection is discussed. Recent advances in knowledge point to avenues for the development of a putative vaccine as well as novel therapeutic strategies. Nevertheless, there are unique unmet challenges that need to be addressed in this regard. Finally, a research agenda is proposed.

Collateral damage: fire and Phytophthora ramorum interact to increase mortality in coast redwood

Treesearch

Margaret R. Metz; J. Morgan Varner; Kerri M. Frangioso; Ross K. Meentemeyer; David M. Rizzo

2013-01-01

Invading species can alter ecosystems by impacting the frequency, severity, and consequences of endemic disturbance regimes (Mack and D'Antonio 1998). Phytophthora ramorum, the causal agent of the emergent disease sudden oak death (SOD), is an invasive pathogen causing widespread tree mortality in coastal forests of California and Oregon. In...

Early detection monitoring of Phytophthora ramorum in high-risk forests of California

Treesearch

Ross Meentemeyer; Elizabeth Lotz; David M. Rizzo; Kelly Buja; Walter Mark

2006-01-01

Early detection monitoring is essential for successful control of invasive organisms. Detection of invasions at an early stage of establishment when a population is small and isolated makes eradication more feasible and less costly. Sudden oak death, caused by the recently described pathogen Phytophthora ramorum, is an emerging forest disease that...

Domestic goose as a model for West Nile virus vaccine efficacy

USDA-ARS?s Scientific Manuscript database

West Nile virus (WNV) is an emergent pathogen in the Americas, first reported in New York during 1999, and has since spread across the United States (USA), Central and South America causing neurological disease in humans, horses and some bird species, including domestic geese. No WNV vaccines are li...

Detoxification of the fusarium toxin fusaric acid by the soil fungus aspergillus tubingensis

USDA-ARS?s Scientific Manuscript database

The fungal pathogen Fusarium oxysporum f. sp. vasinfectum (F.o.v.) causes cotton wilt and produces the toxin fusaric acid (FA). Previous research indicates that in the high producing strains of F.o.v., FA plays an important role in virulence. To address the problems of emerging virulent isolates su...

A review of apple anthracnose canker biology and management in cider apple orchards in the Maritime Pacific Northwest

USDA-ARS?s Scientific Manuscript database

Cider apple (Malus ×domestica Borkh.) is an emerging crop in western Washington and the Pacific Northwest (PNW) region, but a major obstacle to planting new orchards and orchard productivity is the widespread occurrence of apple anthracnose canker, caused by the fungal pathogen Neofabraea malicortic...

Rothia mucilaginosa Prosthetic Device Infections: a Case of Prosthetic Valve Endocarditis

PubMed Central

Tokarczyk, Mindy J.; Jungkind, Donald; DeSimone, Joseph A.

2013-01-01

Rothia mucilaginosa is increasingly recognized as an emerging opportunistic pathogen associated with prosthetic device infections. Infective endocarditis is one of the most common clinical presentations. We report a case of R. mucilaginosa prosthetic valve endocarditis and review the literature of prosthetic device infections caused by this organism. PMID:23467598

Batrachochytrium salamandrivorans: The North American response and a call for action

Treesearch

Matthew J. Gray; James P. Lewis; Priya Nanjappa; Blake Klocke; Frank Pasmans; An Martel; Craig Stephen; Gabriela Parra Olea; Scott A. Smith; Allison Sacerdote-Velat; Michelle R. Christman; Jennifer M. Williams; Deanna H. Olson; Deborah A. Hogan

2015-01-01

Batrachochytrium salamandrivorans (Bsal) is an emerging fungal pathogen that has caused recent die-offs of native salamanders in Europe and is known to be lethal to at least some North American species in laboratory trials [1]. Bsal appears to have originated in Asia, and may have been introduced by humans...

Genomic dissection of nonhost resistance to wheat stem rust in Brachypodium distachyon

USDA-ARS?s Scientific Manuscript database

Wheat stem rust caused by the fungus Puccinia graminis f.sp. tritici (Pgt) is a devastating disease that has largely been controlled for decades by the deployment of resistance genes. However, new races of this pathogen have emerged that overcome many important wheat stem rust resistance genes used ...

DNA-based detection of the fungal pathogen Geomyces destructans in soils from bat hibernacula

Treesearch

Daniel L. Lindner; Andrea Gargas; Jeffrey M. Lorch; Mark T. Banik; Jessie A. Glaeser; Thomas H. Kunz; David S. Blehert

2011-01-01

White-nose syndrome (WNS) is an emerging disease causing unprecedented morbidity and mortality among bats in eastern North America. The disease is characterized by cutaneous infection of hibernating bats by the psychrophilic fungus Geomyces destructans. Detection of G. destructans in environments occupied by bats will be critical...

DEVELOPMENT OF MOLECULAR METHODS TO DETECT ...

EPA Pesticide Factsheets

A large number of human enteric viruses are known to cause gastrointestinal illness and waterborne outbreaks. Many of these are emerging viruses that do not grow or grow poorly in cell culture and so molecular detectoin methods based on the polymerase chain reaction (PCR) are being developed. Current studies focus on detecting two virus groups, the caliciviruses and the hepatitis E virus strains, both of which have been found to cause significant outbraks via contaminated drinking water. Once developed, these methods will be used to collect occurrence data for risk assessment studies. Develop sensitive techniques to detect and identify emerging human waterborne pathogenic viruses and viruses on the CCL.Determine effectiveness of viral indicators to measure microbial quality in water matrices.Support activities: (a) culture and distribution of mammalian cells for Agency and scientific community research needs, (b) provide operator expertise for research requiring confocal and electron microscopy, (c) glassware cleaning, sterilization and biological waste disposal for the Cincinnati EPA facility, (d) operation of infectious pathogenic suite, (e) maintenance of walk-in constant temperature rooms and (f) provide Giardia cysts.

Effects of Drought-Stress on Fusarium Crown Rot Development in Barley

PubMed Central

Liu, Xinlun; Liu, Chunji

2016-01-01

Fusarium crown rot (FCR), caused by various Fusarium species, is a chronic disease of cereals in many semi-arid regions worldwide. To clarify what effects drought-stress may have on FCR development, visual assessment, histological analysis and quantitative PCR were used to analyse the infection process of F. pseudograminearum in barley. This study observed for the first time that the severity of FCR symptom reflects the quantity of pathogens in infected tissues of barley under both drought-stressed and well-watered conditions. Drought-stress prolongs the initial infection phase but enhances the proliferation and spread of Fusarium pathogens after the initial infection phase. Under drought-stressed conditions, the invading hyphae were frequently observed to re-emerge from stomata and invade again the surrounding epidermis cells. Under the well-watered conditions, however, very few hyphae re-emerged from stomata and most infection was caused by hyphae intracellularly grown. It was also observed that drought-stress increased the length and density of trichomes dramatically especially in the susceptible genotypes, and that the length and density of trichomes were positively related to fungal biomass of F. pseudograminearum in plants. PMID:27936004

Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens

PubMed Central

Read, Andrew F.; Baigent, Susan J.; Powers, Claire; Kgosana, Lydia B.; Blackwell, Luke; Smith, Lorraine P.; Kennedy, David A.; Walkden-Brown, Stephen W.; Nair, Venugopal K.

2015-01-01

Could some vaccines drive the evolution of more virulent pathogens? Conventional wisdom is that natural selection will remove highly lethal pathogens if host death greatly reduces transmission. Vaccines that keep hosts alive but still allow transmission could thus allow very virulent strains to circulate in a population. Here we show experimentally that immunization of chickens against Marek's disease virus enhances the fitness of more virulent strains, making it possible for hyperpathogenic strains to transmit. Immunity elicited by direct vaccination or by maternal vaccination prolongs host survival but does not prevent infection, viral replication or transmission, thus extending the infectious periods of strains otherwise too lethal to persist. Our data show that anti-disease vaccines that do not prevent transmission can create conditions that promote the emergence of pathogen strains that cause more severe disease in unvaccinated hosts. PMID:26214839

Rapid emergence of pathogens in agro-ecosystems: global threats to agricultural sustainability and food security.

PubMed

McDonald, Bruce A; Stukenbrock, Eva H

2016-12-05

Agricultural ecosystems are composed of genetically depauperate populations of crop plants grown at a high density and over large spatial scales, with the regional composition of crop species changing little from year to year. These environments are highly conducive for the emergence and dissemination of pathogens. The uniform host populations facilitate the specialization of pathogens to particular crop cultivars and allow the build-up of large population sizes. Population genetic and genomic studies have shed light on the evolutionary mechanisms underlying speciation processes, adaptive evolution and long-distance dispersal of highly damaging pathogens in agro-ecosystems. These studies document the speed with which pathogens evolve to overcome crop resistance genes and pesticides. They also show that crop pathogens can be disseminated very quickly across and among continents through human activities. In this review, we discuss how the peculiar architecture of agro-ecosystems facilitates pathogen emergence, evolution and dispersal. We present four example pathosystems that illustrate both pathogen specialization and pathogen speciation, including different time frames for emergence and different mechanisms underlying the emergence process. Lastly, we argue for a re-design of agro-ecosystems that embraces the concept of dynamic diversity to improve their resilience to pathogens. This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Author(s).

A Molecular Sensor To Characterize Arenavirus Envelope Glycoprotein Cleavage by Subtilisin Kexin Isozyme 1/Site 1 Protease.

PubMed

Oppliger, Joel; da Palma, Joel Ramos; Burri, Dominique J; Bergeron, Eric; Khatib, Abdel-Majid; Spiropoulou, Christina F; Pasquato, Antonella; Kunz, Stefan

2016-01-15

Arenaviruses are emerging viruses including several causative agents of severe hemorrhagic fevers in humans. The advent of next-generation sequencing technology has greatly accelerated the discovery of novel arenavirus species. However, for many of these viruses, only genetic information is available, and their zoonotic disease potential remains unknown. During the arenavirus life cycle, processing of the viral envelope glycoprotein precursor (GPC) by the cellular subtilisin kexin isozyme 1 (SKI-1)/site 1 protease (S1P) is crucial for productive infection. The ability of newly emerging arenaviruses to hijack human SKI-1/S1P appears, therefore, to be a requirement for efficient zoonotic transmission and human disease potential. Here we implement a newly developed cell-based molecular sensor for SKI-1/S1P to characterize the processing of arenavirus GPC-derived target sequences by human SKI-1/S1P in a quantitative manner. We show that only nine amino acids flanking the putative cleavage site are necessary and sufficient to accurately recapitulate the efficiency and subcellular location of arenavirus GPC processing. In a proof of concept, our sensor correctly predicts efficient processing of the GPC of the newly emergent pathogenic Lujo virus by human SKI-1/S1P and defines the exact cleavage site. Lastly, we employed our sensor to show efficient GPC processing of a panel of pathogenic and nonpathogenic New World arenaviruses, suggesting that GPC cleavage represents no barrier for zoonotic transmission of these pathogens. Our SKI-1/S1P sensor thus represents a rapid and robust test system for assessment of the processing of putative cleavage sites derived from the GPCs of newly discovered arenavirus by the SKI-1/S1P of humans or any other species, based solely on sequence information. Arenaviruses are important emerging human pathogens that can cause severe hemorrhagic fevers with high mortality in humans. A crucial step in productive arenavirus infection of human cells is the processing of the viral envelope glycoprotein by the cellular subtilisin kexin isozyme 1 (SKI-1)/site 1 protease (S1P). In order to break the species barrier during zoonotic transmission and cause severe disease in humans, newly emerging arenaviruses must be able to hijack human SKI-1/S1P efficiently. Here we implement a newly developed cell-based molecular sensor for human SKI-1/S1P to characterize the processing of arenavirus glycoproteins in a quantitative manner. We further use our sensor to correctly predict efficient processing of the glycoprotein of the newly emergent pathogenic Lujo virus by human SKI-1/S1P. Our sensor thus represents a rapid and robust test system with which to assess whether the glycoprotein of any newly emerging arenavirus can be efficiently processed by human SKI-1/S1P, based solely on sequence information. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Drivers, dynamics, and control of emerging vector-borne zoonotic diseases

PubMed Central

Kilpatrick, A. Marm; Randolph, Sarah E.

2013-01-01

Emerging vector-borne diseases represent an important issue for global health. Many vector-borne pathogens have appeared in new regions in the past two decades, and many endemic diseases have increased in incidence. Although introductions and local emergence are frequently considered distinct processes, many emerging endemic pathogens are in fact invading at a local scale coincident with habitat change. We highlight key differences in the dynamics and disease burden that result from increased pathogen transmission following habitat change compared with the introduction of pathogens to new regions. Truly in situ emergence is commonly driven by changes in human factors as much as by enhanced enzootic cycles whereas pathogen invasion results from anthropogenic trade and travel and suitable conditions for a pathogen, including hosts, vectors, and climate. Once established, ecological factors related to vector characteristics shape the evolutionary selective pressure on pathogens that may result in increased use of humans as transmission hosts. We describe challenges inherent in the control of vector-borne zoonotic diseases and some emerging non-traditional strategies that may be more effective in the long term. PMID:23200503

PCR-based Approaches for the Detection of Clinical Methicillin-resistant Staphylococcus aureus

PubMed Central

Liu, Ying; Zhang, Jiang; Ji, Yinduo

2016-01-01

Staphylococcus aureus is an important pathogen that can cause a variety of infections, including superficial and systematic infections, in humans and animals. The persistent emergence of multidrug resistant S. aureus, particularly methicillin-resistant S. aureus, has caused dramatically economic burden and concerns in the public health due to limited options of treatment of MRSA infections. In order to make a correct choice of treatment for physicians and understand the prevalence of MRSA, it is extremely critical to precisely and timely diagnose the pathogen that induces a specific infection of patients and to reveal the antibiotic resistant profile of the pathogen. In this review, we outlined different PCR-based approaches that have been successfully utilized for the rapid detection of S. aureus, including MRSA and MSSA, directly from various clinical specimens. The sensitivity and specificity of detections were pointed out. Both advantages and disadvantages of listed approaches were discussed. Importantly, an alternative approach is necessary to further confirm the detection results from the molecular diagnostic assays. PMID:27335617

Emerging borreliae - Expanding beyond Lyme borreliosis.

PubMed

Cutler, Sally J; Ruzic-Sabljic, Eva; Potkonjak, Aleksandar

2017-02-01

Lyme borreliosis (or Lyme disease) has become a virtual household term to the exclusion of other forgotten, emerging or re-emerging borreliae. We review current knowledge regarding these other borreliae, exploring their ecology, epidemiology and pathological potential, for example, for the newly described B. mayonii. These bacteria range from tick-borne, relapsing fever-inducing strains detected in some soft ticks, such as B. mvumii, to those from bat ticks resembling B. turicatae. Some of these emerging pathogens remain unnamed, such as the borrelial strains found in South African penguins and some African cattle ticks. Others, such as B. microti and unnamed Iranian strains, have not been recognised through a lack of discriminatory diagnostic methods. Technical improvements in phylogenetic methods have allowed the differentiation of B. merionesi from other borrelial species that co-circulate in the same region. Furthermore, we discuss members that challenge the existing dogma that Lyme disease-inducing strains are transmitted by hard ticks, whilst the relapsing fever-inducing spirochaetes are transmitted by soft ticks. Controversially, the genus has now been split with Lyme disease-associated members being transferred to Borreliella, whilst the relapsing fever species retain the Borrelia genus name. It took some 60 years for the correlation with clinical presentations now known as Lyme borreliosis to be attributed to their spirochaetal cause. Many of the borreliae discussed here are currently considered exotic curiosities, whilst others, such as B. miyamotoi, are emerging as significant causes of morbidity. To elucidate their role as potential pathogenic agents, we first need to recognise their presence through suitable diagnostic approaches. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mechanisms of pathogenesis of emerging adenoviruses.

PubMed

Cook, James; Radke, Jay

2017-01-01

Periodic outbreaks of human adenovirus infections can cause severe illness in people with no known predisposing conditions. The reasons for this increased viral pathogenicity are uncertain. Adenoviruses are constantly undergoing mutation during circulation in the human population, but related phenotypic changes of the viruses are rarely detected because of the infrequency of such outbreaks and the limited biological studies of the emergent strains. Mutations and genetic recombinations have been identified in these new strains. However, the linkage between these genetic changes and increased pathogenicity is poorly understood. It has been observed recently that differences in virus-induced immunopathogenesis can be associated with altered expression of non-mutant viral genes associated with changes in viral modulation of the host innate immune response. Initial small animal studies indicate that these changes in viral gene expression can be associated with enhanced immunopathogenesis in vivo . Available evidence suggests the hypothesis that there is a critical threshold of expression of certain viral genes that determines both the sustainability of viral transmission in the human population and the enhancement of immunopathogenesis. Studies of this possibility will require extension of the analysis of outbreak viral strains from a sequencing-based focus to biological studies of relationships between viral gene expression and pathogenic responses. Advances in this area will require increased coordination among public health organizations, diagnostic microbiology laboratories, and research laboratories to identify, catalog, and systematically study differences between prototype and emergent viral strains that explain the increased pathogenicity that can occur during clinical outbreaks.

The Genome Biology of Effector Gene Evolution in Filamentous Plant Pathogens.

PubMed

Sánchez-Vallet, Andrea; Fouché, Simone; Fudal, Isabelle; Hartmann, Fanny E; Soyer, Jessica L; Tellier, Aurélien; Croll, Daniel

2018-05-16

Filamentous pathogens, including fungi and oomycetes, pose major threats to global food security. Crop pathogens cause damage by secreting effectors that manipulate the host to the pathogen's advantage. Genes encoding such effectors are among the most rapidly evolving genes in pathogen genomes. Here, we review how the major characteristics of the emergence, function, and regulation of effector genes are tightly linked to the genomic compartments where these genes are located in pathogen genomes. The presence of repetitive elements in these compartments is associated with elevated rates of point mutations and sequence rearrangements with a major impact on effector diversification. The expression of many effectors converges on an epigenetic control mediated by the presence of repetitive elements. Population genomics analyses showed that rapidly evolving pathogens show high rates of turnover at effector loci and display a mosaic in effector presence-absence polymorphism among strains. We conclude that effective pathogen containment strategies require a thorough understanding of the effector genome biology and the pathogen's potential for rapid adaptation. Expected final online publication date for the Annual Review of Phytopathology Volume 56 is August 25, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Emerging infectious diseases of plants: pathogen pollution, climate change and agrotechnology drivers.

PubMed

Anderson, Pamela K; Cunningham, Andrew A; Patel, Nikkita G; Morales, Francisco J; Epstein, Paul R; Daszak, Peter

2004-10-01

Emerging infectious diseases (EIDs) pose threats to conservation and public health. Here, we apply the definition of EIDs used in the medical and veterinary fields to botany and highlight a series of emerging plant diseases. We include EIDs of cultivated and wild plants, some of which are of significant conservation concern. The underlying cause of most plant EIDs is the anthropogenic introduction of parasites, although severe weather events are also important drivers of disease emergence. Much is known about crop plant EIDs, but there is little information about wild-plant EIDs, suggesting that their impact on conservation is underestimated. We conclude with recommendations for improving strategies for the surveillance and control of plant EIDs.

Colony Collapse Disorder: A Descriptive Study

PubMed Central

vanEngelsdorp, Dennis; Evans, Jay D.; Saegerman, Claude; Mullin, Chris; Haubruge, Eric; Nguyen, Bach Kim; Frazier, Maryann; Frazier, Jim; Cox-Foster, Diana; Chen, Yanping; Underwood, Robyn; Tarpy, David R.; Pettis, Jeffery S.

2009-01-01

Background Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L.) colonies in the United States. In the absence of a known cause, this syndrome was named Colony Collapse Disorder (CCD) because the main trait was a rapid loss of adult worker bees. We initiated a descriptive epizootiological study in order to better characterize CCD and compare risk factor exposure between populations afflicted by and not afflicted by CCD. Methods and Principal Findings Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCD. Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor) were higher in control colonies than CCD-affected colonies. Conclusions/Significance This is the first comprehensive survey of CCD-affected bee populations that suggests CCD involves an interaction between pathogens and other stress factors. We present evidence that this condition is contagious or the result of exposure to a common risk factor. Potentially important areas for future hypothesis-driven research, including the possible legacy effect of mite parasitism and the role of honey bee resistance to pesticides, are highlighted. PMID:19649264

Colony collapse disorder: a descriptive study.

PubMed

Vanengelsdorp, Dennis; Evans, Jay D; Saegerman, Claude; Mullin, Chris; Haubruge, Eric; Nguyen, Bach Kim; Frazier, Maryann; Frazier, Jim; Cox-Foster, Diana; Chen, Yanping; Underwood, Robyn; Tarpy, David R; Pettis, Jeffery S

2009-08-03

Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L.) colonies in the United States. In the absence of a known cause, this syndrome was named Colony Collapse Disorder (CCD) because the main trait was a rapid loss of adult worker bees. We initiated a descriptive epizootiological study in order to better characterize CCD and compare risk factor exposure between populations afflicted by and not afflicted by CCD. Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCD. Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor) were higher in control colonies than CCD-affected colonies. This is the first comprehensive survey of CCD-affected bee populations that suggests CCD involves an interaction between pathogens and other stress factors. We present evidence that this condition is contagious or the result of exposure to a common risk factor. Potentially important areas for future hypothesis-driven research, including the possible legacy effect of mite parasitism and the role of honey bee resistance to pesticides, are highlighted.

So Near and Yet So Far: Harmonic Radar Reveals Reduced Homing Ability of Nosema Infected Honeybees

PubMed Central

Wolf, Stephan; McMahon, Dino P.; Lim, Ka S.; Pull, Christopher D.; Clark, Suzanne J.; Paxton, Robert J.; Osborne, Juliet L.

2014-01-01

Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed. PMID:25098331

Epidemiology, clinical features, diagnosis and treatment of Haemophilus ducreyi - a disappearing pathogen?

PubMed

Lewis, David A

2014-06-01

Chancroid, caused by Haemophilus ducreyi, has declined in importance as a sexually transmitted pathogen in most countries where it was previously endemic. The global prevalence of chancroid is unknown as most countries lack the required laboratory diagnostic capacity and surveillance systems to determine this. H. ducreyi has recently emerged as a cause of chronic skin ulceration in some South Pacific islands. Although no antimicrobial susceptibility data for H. ducreyi have been published for two decades, it is still assumed that the infection will respond successfully to treatment with recommended cephalosporin, macrolide or fluoroquinolone-based regimens. HIV-1-infected patients require careful follow-up due to reports of treatment failure with single dose regimens. Buboes may need additional treatment with either aspiration or excision and drainage.

Xylella fastidiosa: an examination of a re-emerging plant pathogen.

PubMed

Rapicavoli, Jeannette; Ingel, Brian; Blanco-Ulate, Barbara; Cantu, Dario; Roper, Caroline

2018-04-01

Xylella fastidiosa is a Gram-negative bacterial plant pathogen with an extremely wide host range. This species has recently been resolved into subspecies that correlate with host specificity. This review focuses on the status of X. fastidiosa pathogenic associations in plant hosts in which the bacterium is either endemic or has been recently introduced. Plant diseases associated with X. fastidiosa have been documented for over a century, and much about what is known in the context of host-pathogen interactions is based on these hosts, such as grape and citrus, in which this pathogen has been well described. Recent attention has focused on newly emerging X. fastidiosa diseases, such as in olives. Bacteria; Gammaproteobacteria; family Xanthomonadaceae; genus Xylella; species fastidiosa. Gram-negative rod (0.25-0.35 × 0.9-3.5 μm), non-flagellate, motile via Type IV pili-mediated twitching, fastidious. Xylella fastidiosa has a broad host range that includes ornamental, ecological and agricultural plants belonging to over 300 different species in 63 different families. To date, X. fastidiosa has been found to be pathogenic in over 100 plant species. In addition, it can establish non-symptomatic associations with many plants as a commensal endophyte. Here, we list the four distinct subspecies of X. fastidiosa and some of the agriculturally relevant diseases caused by them: X. fastidiosa ssp. fastidiosa causes Pierce's disease (PD) of grapevine (Vitis vinifera); X. fastidiosa ssp. multiplex causes almond leaf scorch (ALS) and diseases on other nut and shade tree crops; X. fastidiosa ssp. pauca causes citrus variegated chlorosis (CVC) (Citrus spp.), coffee leaf scorch and olive quick decline syndrome (OQDS) (Olea europaea); X. fastidiosa ssp. sandyi causes oleander leaf scorch (OLS) (Nerium oleander). Significant host specificity seemingly exists for some of the subspecies, although this could be a result of technical biases based on the limited number of plants tested, whereas some subspecies are not as stringent in their host range and can infect several plant hosts. Most X. fastidiosa-related diseases appear as marginal leaf necrosis and scorching of the leaves. In the case of PD, X. fastidiosa can also cause desiccation of berries (termed 'raisining'), irregular periderm development and abnormal abscission of petioles. In olive trees affected with OQDS, leaves exhibit marginal necrosis and defoliation, and overall tree decline occurs. Plants with ALS and OLS also exhibit the characteristic leaf scorch symptoms. Not all X. fastidiosa-related diseases exhibit the typical leaf scorch symptoms. These include CVC and Phony Peach disease, amongst others. In the case of CVC, symptoms include foliar wilt and interveinal chlorosis on the upper surfaces of the leaves (similar to zinc deficiency), which correspond to necrotic, gum-like regions on the undersides of the leaves. Additional symptoms of CVC include defoliation, dieback and hardening of fruits. Plants infected with Phony Peach disease exhibit a denser, more compact canopy (as a result of shortened internodes, darker green leaves and delayed leaf senescence), premature bloom and reduced fruit size. Some occlusions occur in the xylem vessels, but there are no foliar wilting, chlorosis or necrosis symptoms . USEFUL WEBSITES: http://www.piercesdisease.org/; https://pubmlst.org/xfastidiosa/; http://www.xylella.lncc.br/; https://nature.berkeley.edu/xylella/; https://ec.europa.eu/food/plant/plant_health_biosecurity/legislation/emergency_measures/xylella-fastidiosa_en. © 2017 BSPP AND JOHN WILEY & SONS LTD.

Multiplex Polymerase Chain Reaction for Detection of Gastrointestinal Pathogens in Migrant Workers in Qatar.

PubMed

Humphrey, John M; Ranbhise, Sanjay; Ibrahim, Emad; Al-Romaihi, Hamad E; Farag, Elmoubasher; Abu-Raddad, Laith J; Glesby, Marshall J

2016-12-07

The causes of infectious diarrhea among the migrant worker population in Qatar are not well understood. We conducted a prospective observational study to understand the demographic and clinical characteristics and infectious causes of diarrhea among migrant workers in Doha, Qatar. A total of 126 male workers presenting to the Qatar Red Crescent Worker's Health Center outpatient clinic or emergency department were studied over a 5-month period in 2015-2016. Epidemiologic surveys were administered to all subjects and the prevalence of 22 different stool pathogens was determined using multiplex polymerase chain reaction (PCR) (FilmArray ® Gastrointestinal PCR). A target pathogen was identified in 62.7% of subjects. Enteropathogenic Escherichia coli was the most prevalent pathogen and was detected in 24.6% of subjects, followed by Salmonella (22.2%), enteroaggregative E. coli (15.1%), Giardia lamblia (9.5%), and enterotoxigenic E. coli (8.7%). Multiple pathogens were identified in 49.3% of positive stool samples. In a multivariable analysis, the presence of a heart rate ≥ 90 (adjusted odds ratio [OR] = 3.7, 95% confidence interval [CI] = 1.4-10.0) and > 5 fecal leukocytes/high-power field (adjusted OR = 2.8, 95% CI = 1.2-7.0) were significant predictors of detecting an acute inflammatory pathogen by PCR. Use of multiplex PCR enabled the detection of gastrointestinal pathogens in a high proportion of cases, illustrating the utility of this diagnostic tool in epidemiologic studies of infectious diarrhea. © The American Society of Tropical Medicine and Hygiene.

In Vitro Emergence of High Persistence upon Periodic Aminoglycoside Challenge in the ESKAPE Pathogens.

PubMed

Michiels, Joran Elie; Van den Bergh, Bram; Verstraeten, Natalie; Fauvart, Maarten; Michiels, Jan

2016-08-01

Health care-associated infections present a major threat to modern medical care. Six worrisome nosocomial pathogens-Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.-are collectively referred to as the "ESKAPE bugs." They are notorious for extensive multidrug resistance, yet persistence, or the phenotypic tolerance displayed by a variant subpopulation, remains underappreciated in these pathogens. Importantly, persistence can prevent eradication of antibiotic-sensitive bacterial populations and is thought to act as a catalyst for the development of genetic resistance. Concentration- and time-dependent aminoglycoside killing experiments were used to investigate persistence in the ESKAPE pathogens. Additionally, a recently developed method for the experimental evolution of persistence was employed to investigate adaptation to high-dose, extended-interval aminoglycoside therapy in vitro We show that ESKAPE pathogens exhibit biphasic killing kinetics, indicative of persister formation. In vitro cycling between aminoglycoside killing and persister cell regrowth, evocative of clinical high-dose extended-interval therapy, caused a 37- to 213-fold increase in persistence without the emergence of resistance. Increased persistence also manifested in biofilms and provided cross-tolerance to different clinically important antibiotics. Together, our results highlight a possible drawback of intermittent, high-dose antibiotic therapy and suggest that clinical diagnostics might benefit from taking into account persistence. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Emerging and Neglected Infectious Diseases: Insights, Advances, and Challenges

PubMed Central

2017-01-01

Infectious diseases are a significant burden on public health and economic stability of societies all over the world. They have for centuries been among the leading causes of death and disability and presented growing challenges to health security and human progress. The threat posed by infectious diseases is further deepened by the continued emergence of new, unrecognized, and old infectious disease epidemics of global impact. Over the past three and half decades at least 30 new infectious agents affecting humans have emerged, most of which are zoonotic and their origins have been shown to correlate significantly with socioeconomic, environmental, and ecological factors. As these factors continue to increase, putting people in increased contact with the disease causing pathogens, there is concern that infectious diseases may continue to present a formidable challenge. Constant awareness and pursuance of effective strategies for controlling infectious diseases and disease emergence thus remain crucial. This review presents current updates on emerging and neglected infectious diseases and highlights the scope, dynamics, and advances in infectious disease management with particular focus on WHO top priority emerging infectious diseases (EIDs) and neglected tropical infectious diseases. PMID:28286767

Emerging and Neglected Infectious Diseases: Insights, Advances, and Challenges.

PubMed

Nii-Trebi, Nicholas Israel

2017-01-01

Infectious diseases are a significant burden on public health and economic stability of societies all over the world. They have for centuries been among the leading causes of death and disability and presented growing challenges to health security and human progress. The threat posed by infectious diseases is further deepened by the continued emergence of new, unrecognized, and old infectious disease epidemics of global impact. Over the past three and half decades at least 30 new infectious agents affecting humans have emerged, most of which are zoonotic and their origins have been shown to correlate significantly with socioeconomic, environmental, and ecological factors. As these factors continue to increase, putting people in increased contact with the disease causing pathogens, there is concern that infectious diseases may continue to present a formidable challenge. Constant awareness and pursuance of effective strategies for controlling infectious diseases and disease emergence thus remain crucial. This review presents current updates on emerging and neglected infectious diseases and highlights the scope, dynamics, and advances in infectious disease management with particular focus on WHO top priority emerging infectious diseases (EIDs) and neglected tropical infectious diseases.

The Microbial Rosetta Stone Database: A compilation of global and emerging infectious microorganisms and bioterrorist threat agents

PubMed Central

Ecker, David J; Sampath, Rangarajan; Willett, Paul; Wyatt, Jacqueline R; Samant, Vivek; Massire, Christian; Hall, Thomas A; Hari, Kumar; McNeil, John A; Büchen-Osmond, Cornelia; Budowle, Bruce

2005-01-01

Background Thousands of different microorganisms affect the health, safety, and economic stability of populations. Many different medical and governmental organizations have created lists of the pathogenic microorganisms relevant to their missions; however, the nomenclature for biological agents on these lists and pathogens described in the literature is inexact. This ambiguity can be a significant block to effective communication among the diverse communities that must deal with epidemics or bioterrorist attacks. Results We have developed a database known as the Microbial Rosetta Stone. The database relates microorganism names, taxonomic classifications, diseases, specific detection and treatment protocols, and relevant literature. The database structure facilitates linkage to public genomic databases. This paper focuses on the information in the database for pathogens that impact global public health, emerging infectious organisms, and bioterrorist threat agents. Conclusion The Microbial Rosetta Stone is available at . The database provides public access to up-to-date taxonomic classifications of organisms that cause human diseases, improves the consistency of nomenclature in disease reporting, and provides useful links between different public genomic and public health databases. PMID:15850481

Tracking cashew economically important diseases in the West African region using metagenomics

PubMed Central

Monteiro, Filipa; Romeiras, Maria M.; Figueiredo, Andreia; Sebastiana, Mónica; Baldé, Aladje; Catarino, Luís; Batista, Dora

2015-01-01

During the last decades, agricultural land-uses in West Africa were marked by dramatic shifts in the coverage of individual crops. Nowadays, cashew (Anacardium occidentale L.) is one of the most export-oriented horticulture crops, notably in Guinea-Bissau. Relying heavily on agriculture to increase their income, developing countries have been following a strong trend of moving on from traditional farming systems toward commercial production. Emerging infectious diseases, driven either by adaptation to local conditions or inadvertent importation of plant pathogens, are able to cause tremendous cashew production losses, with economic and social impact of which, in developing countries is often underestimated. Presently, plant genomics with metagenomics as an emergent tool, presents an enormous potential to better characterize diseases by providing extensive knowledge on plant pathogens at a large scale. In this perspective, we address metagenomics as a promising genomic tool to identify cashew fungal associated diseases as well as to discriminate the causal pathogens, aiming at obtaining tools to help design effective strategies for disease control and thus promote the sustainable production of cashew in West African Region. PMID:26175748

Tracking cashew economically important diseases in the West African region using metagenomics.

PubMed

Monteiro, Filipa; Romeiras, Maria M; Figueiredo, Andreia; Sebastiana, Mónica; Baldé, Aladje; Catarino, Luís; Batista, Dora

2015-01-01

During the last decades, agricultural land-uses in West Africa were marked by dramatic shifts in the coverage of individual crops. Nowadays, cashew (Anacardium occidentale L.) is one of the most export-oriented horticulture crops, notably in Guinea-Bissau. Relying heavily on agriculture to increase their income, developing countries have been following a strong trend of moving on from traditional farming systems toward commercial production. Emerging infectious diseases, driven either by adaptation to local conditions or inadvertent importation of plant pathogens, are able to cause tremendous cashew production losses, with economic and social impact of which, in developing countries is often underestimated. Presently, plant genomics with metagenomics as an emergent tool, presents an enormous potential to better characterize diseases by providing extensive knowledge on plant pathogens at a large scale. In this perspective, we address metagenomics as a promising genomic tool to identify cashew fungal associated diseases as well as to discriminate the causal pathogens, aiming at obtaining tools to help design effective strategies for disease control and thus promote the sustainable production of cashew in West African Region.

Human meningitis due to Streptococcus suis in Lomé, Togo: a case report.

PubMed

Prince-David, Mireille; Salou, Mounerou; Marois-Créhan, Corinne; Assogba, Komi; Plainvert, Céline; Balogou, Koffi A; Poyart, Claire; Tazi, Asmaa

2016-11-08

Streptococcus suis is a zoonotic pathogen which represents the leading cause of meningitis in Southeast Asia and an emerging pathogen in the Western world, the main risk factor for infection being contact with pigs. In Africa, the prevalence of S. suis infections in swine and humans is largely unrecognized, with only one recent report of a limited case series. We describe a human case of meningitis due to S. suis in a 32-year-old man living in Togo. The patient had no particular medical history and no risk factors for immunodeficiency but reported regular contact with pork products. Using specific immunological and molecular methods, we characterized the isolate as S. suis serotype 2, ST1, one the most prevalent and virulent clone worldwide. The outcome was favorable after one week of adapted antibiotic therapy but the patient was left with severe hearing disorders. This work highlights the emergence of this pathogen in Africa and reinforces the need for accurate epidemiological and surveillance studies of S. suis infections and for educating clinicians and exposed groups in non-endemic countries.

Get It through Your Thick Head: Emerging Principles in Neuroimmunology and Neurovirology Redefine Central Nervous System "Immune Privilege".

PubMed

Solomos, Andreas C; Rall, Glenn F

2016-04-20

The central nervous system (CNS) coordinates all aspects of life, autonomic and sentient, though how it has evolved to contend with pathogenic infections remains, to a great degree, a mystery. The skull and cerebrospinal fluid (CSF) provide protection from blunt force contacts, and it was once thought that the blood-brain barrier (BBB) was a fortress that restricted pathogen entry and limited inflammation. Recent studies, however, have caused a revision of this viewpoint: the CNS is monitored by blood-borne lymphocytes, but can use alternative strategies to prevent or resolve many pathogenic challenges. In this Review, we discuss emerging principles that indicate how the CNS is immunologically unique from peripheral tissues. We focus on developments that include glymphatics, recently characterized brain lymphatic vessels, distinctions in innate and adaptive immune strategies, novel points of entry for neurotropic viruses, and, finally, how the periphery can influence CNS homeostasis and immune responses within the brain. Collectively, these attributes demand a re-evaluation of immunity in the brain: not privileged, but distinct.

Emerging IL-12 family cytokines in the fight against fungal infections.

PubMed

Thompson, Aiysha; Orr, Selinda J

2018-05-21

Invasive fungal infections cause approximately 1.5 million deaths per year worldwide and are a growing threat to human health. Current anti-fungal therapies are often insufficient, therefore studies into host-pathogen interactions are critical for the development of novel therapies to improve mortality rates. Myeloid cells, such as macrophages and dendritic cells, express pattern recognition receptor (PRRs), which are important for fungal recognition. Engagement of these PRRs by fungal pathogens induces multiple cytokines, which in turn activate T effector responses. Interleukin (IL)-12 family members (IL-12p70, IL-23, IL-27 and IL-35) link innate immunity with the development of adaptive immunity and are also important for regulating T cell responses. IL-12 and IL-23 have established roles during anti-fungal immunity, whereas emerging roles for IL-27 and IL-35 have recently been reported. Here, we discuss the IL-12 family, focusing on IL-27 and IL-35 during anti-fungal immune responses to pathogens such as Candida and Aspergillus. Copyright © 2018. Published by Elsevier Ltd.

ESTABLISH AND STANDARDIZE METHODOLOGY FOR ...

EPA Pesticide Factsheets

Research is conducted to develop and standardize methods to detect and measure occurrence of human enteric viruses that cause waterborne disease. The viruses of concern include the emerging pathogens--hepatitis E virus and group B rotaviruses. Also of concern are the coxsackieviruses and echoviruses--two members of the Office of Water's Contaminant Candidate List (CCL). Under this task, indicators of fecal pollution are also being evaluated as to their importance in evaluating microbial water quality. Another focus of the research is to address the standardization, evaluation and promulgation of detection methods for bacterial viruses. Develop sensitive techniques to detect and identify emerging human waterborne pathogenic viruses and viruses on the CCL.Determine effectiveness of viral indicators to measure microbial quality in water matrices.Support activities: (a) culture and distribution of mammalian cells for Agency and scientific community research needs, (b) provide operator expertise for research requiring confocal and electron microscopy, (c) glassware cleaning, sterilization and biological waste disposal for the Cincinnati EPA facility, (d) operation of infectious pathogenic suite, (e) maintenance of walk-in constant temperature rooms and (f) provide Giardia cysts.

Emergence and Adaptation of a Novel Highly Pathogenic H7N9 Influenza Virus in Birds and Humans from a 2013 Human-Infecting Low-Pathogenic Ancestor.

PubMed

Qi, Wenbao; Jia, Weixin; Liu, Di; Li, Jing; Bi, Yuhai; Xie, Shumin; Li, Bo; Hu, Tao; Du, Yingying; Xing, Li; Zhang, Jiahao; Zhang, Fuchun; Wei, Xiaoman; Eden, John-Sebastian; Li, Huanan; Tian, Huaiyu; Li, Wei; Su, Guanming; Lao, Guangjie; Xu, Chenggang; Xu, Bing; Liu, Wenjun; Zhang, Guihong; Ren, Tao; Holmes, Edward C; Cui, Jie; Shi, Weifeng; Gao, George F; Liao, Ming

2018-01-15

Since its emergence in 2013, the H7N9 low-pathogenic avian influenza virus (LPAIV) has been circulating in domestic poultry in China, causing five waves of human infections. A novel H7N9 highly pathogenic avian influenza virus (HPAIV) variant possessing multiple basic amino acids at the cleavage site of the hemagglutinin (HA) protein was first reported in two cases of human infection in January 2017. More seriously, those novel H7N9 HPAIV variants have been transmitted and caused outbreaks on poultry farms in eight provinces in China. Herein, we demonstrate the presence of three different amino acid motifs at the cleavage sites of these HPAIV variants which were isolated from chickens and humans and likely evolved from the preexisting LPAIVs. Animal experiments showed that these novel H7N9 HPAIV variants are both highly pathogenic in chickens and lethal to mice. Notably, human-origin viruses were more pathogenic in mice than avian viruses, and the mutations in the PB2 gene associated with adaptation to mammals (E627K, A588V, and D701N) were identified by next-generation sequencing (NGS) and Sanger sequencing of the isolates from infected mice. No polymorphisms in the key amino acid substitutions of PB2 and HA in isolates from infected chicken lungs were detected by NGS. In sum, these results highlight the high degree of pathogenicity and the valid transmissibility of this new H7N9 variant in chickens and the quick adaptation of this new H7N9 variant to mammals, so the risk should be evaluated and more attention should be paid to this variant. IMPORTANCE Due to the recent increased numbers of zoonotic infections in poultry and persistent human infections in China, influenza A(H7N9) virus has remained a public health threat. Most of the influenza A(H7N9) viruses reported previously have been of low pathogenicity. Now, these novel H7N9 HPAIV variants have caused human infections in three provinces and outbreaks on poultry farms in eight provinces in China. We analyzed the molecular features and compared the relative characteristics of one H7N9 LPAIV and two H7N9 HPAIVs isolated from chickens and two human-origin H7N9 HPAIVs in chicken and mouse models. We found that all HPAIVs both are highly pathogenic and have valid transmissibility in chickens. Strikingly, the human-origin viruses were more highly pathogenic than the avian-origin viruses in mice, and dynamic mutations were confirmed by NGS and Sanger sequencing. Our findings offer important insight into the origin, adaptation, pathogenicity, and transmissibility of these viruses to both poultry and mammals. Copyright © 2018 American Society for Microbiology.

Status of Phytophthora ramorum and P. kernoviae in Europe

Treesearch

Joan F. Webber

2008-01-01

Following the recognition that Phytophthora ramorum (the cause of sudden oak death in the U.S.) was present in Europe as well as America, emergency European Community (EC) phytosanitary measures were put in place in September 2002 to prevent spread of P. ramorum, and also to stop introductions of the pathogen from elsewhere. A 3...

The effects of sudden oak death and wildfire on forest composition and dynamics in the Big Sur Ecoregion of Coastal California

Treesearch

Margaret R. Metz; Kerri M. Frangioso; Ross K. Meentemeyer; David M. Rizzo

2012-01-01

Sudden oak death (SOD), caused by Phytophthora ramorum, is an emerging forest disease associated with extensive tree mortality in coastal California forests (Rizzo et al. 2005). P. ramorum is a generalist pathogen that infects many hosts, but hosts differ in their ability to transmit the disease...

Tree diseases as a cause and consequence of interacting forest disturbances

Treesearch

Richard Cobb; Margaret Metz

2017-01-01

The disease triangle is a basic and highly flexible tool used extensively in forest pathology. By linking host, pathogen, and environmental factors, the model provides etiological insights into disease emergence. Landscape ecology, as a field, focuses on spatially heterogeneous environments and is most often employed to understand the dynamics of relatively large areas...

Genetic diversification of an emerging pathogen: A decade of mutation by the fish Viral Hemorrhagic Septicemia (VHS) virus in the Laurentian Great Lakes

USDA-ARS?s Scientific Manuscript database

Viral Hemorrhagic Septicemia virus (VHSv) is an RNA rhabdovirus, which causes one of the world's most serious fish diseases, infecting >80 freshwater and marine species across the Northern Hemisphere. A new, novel, and especially virulent substrain - VHSv-IVb - first appeared in the Laurentian Gre...

Identifying Plants of Stampede Pinto Bean with Resistance to New races of Rust Pathogen

USDA-ARS?s Scientific Manuscript database

The rust disease of dry beans is caused by a hyper-variable fungus that continually produces new virulent strains. Two new strains, known as races, emerged in Michigan and North Dakota in 2007 and 2008, respectively, which surmounted the resistance of a widely used rust-resistance gene known as Ur-...

Gordonia bronchialis bacteremia and pleural infection: case report and review of the literature.

PubMed

Johnson, Jennifer A; Onderdonk, Andrew B; Cosimi, Lisa A; Yawetz, Sigal; Lasker, Brent A; Bolcen, Shanna J; Brown, June M; Marty, Francisco M

2011-04-01

Gordonia species are aerobic actinomycetes recently recognized as causing human disease, often in the setting of intravascular catheter-related infections. We describe a case of Gordonia bronchialis bacteremia and pleural space infection in the absence of an indwelling intravascular catheter and review the breadth of reported infections with this emerging pathogen.

Analysis of populations of the sudden oak death pathogen in Oregon forests

Treesearch

Zhian N. Kamvar; Everett M. Hansen; Alan M. Kanaskie; Meredith M. Larsen; Niklaus J. Grünwald

2017-01-01

Sudden oak death, caused by the oomycete Phytophthora ramorum, was first discovered in California toward the end of the 20th century and subsequently emerged on tanoak forests in Oregon before its first detection in 2001 by aerial surveys. The Oregon Department of Forestry has since monitored the epidemic and sampled symptomatic tanoak trees from...

Heterogeneous occupancy and density estimates of the pathogenic fungus Batrachochytrium dendrobatidis in waters of North America

Treesearch

Tara Chestnut; Chauncey Anderson; Radu Popa; Andrew R. Blaustein; Mary Voytek; Deanna H. Olson; Julie Kirshtein

2014-01-01

Biodiversity losses are occurring worldwide due to a combination of stressors. For example, by one estimate, 40% of amphibian species are vulnerable to extinction, and disease is one threat to amphibian populations. The emerging infectious disease chytridiomycosis, caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd), is a contributor to amphibian declines...

Effects of individual, community and landscape drivers on the dynamics of a wildland forest epidemic

Treesearch

Sarah E. Haas; J. Hall Cushman; Whalen W. Dillon; Nathan E. Rank; David M. Rizzo; Ross K. Meentemeyer

2016-01-01

The challenges posed by observing host-pathogen-environment interactions across large geographic extents and over meaningful time scales limit our ability to understand and manage wildland epidemics. We conducted a landscape-scale, longitudinal study designed to analyze the dynamics of sudden oak death (an emerging forest disease caused by Phytophthora...

Microbead based assays for detection and characterization of E. coli in pure cultures

USDA-ARS?s Scientific Manuscript database

Recently, the Centers for Disease Control and Prevention (CDC) has identified that the top 6 non-O157 Shiga toxin-producing E. coli (STEC) are emerging pathogens presenting significant risks of disease. These, as well as the infamous E. coli O157, cause an estimated 265,000 infections each year in t...

Characterization of resistance to stripe rust in contemporary cultivars and lines of winter wheat

USDA-ARS?s Scientific Manuscript database

Stripe rust, caused by Puccinia striiformis f. sp. tritici, has been an important disease of winter wheat in the eastern United States since 2000 when a new strain of the pathogen emerged. The new strain was more aggressive and better adapted to warmer temperatures than the old strain, and overcame ...

Controlling Infectious Diseases in Nurseries

Treesearch

T. H. Filer

1968-01-01

At least 300 publications have been written about non-infectious and infectious diseases of tree seedlings. I will outline some of the progress that is being made in finding ways to control infectious diseases, those caused by pathogens. I will touch upon pre- and post-emergence damping-off, root rots, leaf spots, and fusiform rust, which are the most serious diseases...

Iquitos Virus: A Novel Reassortant Orthobunyavirus Associated with Human Illness in Peru

PubMed Central

Aguilar, Patricia V.; Barrett, Alan D.; Saeed, Mohammad F.; Watts, Douglas M.; Russell, Kevin; Guevara, Carolina; Ampuero, Julia S.; Suarez, Luis; Cespedes, Manuel; Montgomery, Joel M.; Halsey, Eric S.; Kochel, Tadeusz J.

2011-01-01

Oropouche (ORO) virus, a member of the Simbu serogroup, is one of the few human pathogens in the Orthobunyavirus genus in the family Bunyaviridae. Genetic analyses of ORO-like strains from Iquitos, Peru, identified a novel reassortant containing the S and L segments of ORO virus and the M segment of a novel Simbu serogroup virus. This new pathogen, which we named Iquitos (IQT) virus, was first isolated during 1999 from a febrile patient in Iquitos, an Amazonian city in Peru. Subsequently, the virus was identified as the cause of outbreaks of “Oropouche fever” during 2005 and 2006 in Iquitos. In addition to the identification of 17 isolates of IQT virus between 1999 and 2006, surveys for neutralizing antibody among Iquitos residents revealed prevalence rates of 14.9% for ORO virus and 15.4% for IQT virus. Limited studies indicate that prior infection with ORO virus does not seem to protect against disease caused with the IQT virus infection. Identification of a new Orthobunyavirus human pathogen in the Amazon region of Peru highlights the need for strengthening surveillance activities and laboratory capabilities, and investigating the emergence of new pathogens in tropical regions of South America. PMID:21949892

Non-Cholera Vibrios: The Microbial Barometer of Climate Change.

PubMed

Baker-Austin, Craig; Trinanes, Joaquin; Gonzalez-Escalona, Narjol; Martinez-Urtaza, Jaime

2017-01-01

There is a growing interest in the role of climate change in driving the spread of waterborne infectious diseases, such as those caused by bacterial pathogens. One particular group of pathogenic bacteria - vibrios - are a globally important cause of diseases in humans and aquatic animals. These Gram-negative bacteria, including the species Vibrio vulnificus, Vibrio parahaemolyticus and Vibrio cholerae, grow in warm, low-salinity waters, and their abundance in the natural environment mirrors ambient environmental temperatures. In a rapidly warming marine environment, there are greater numbers of human infections, and most notably outbreaks linked to extreme weather events such as heatwaves in temperate regions such as Northern Europe. Because the growth of pathogenic vibrios in the natural environment is largely dictated by temperature, we argue that this group of pathogens represents an important and tangible barometer of climate change in marine systems. We provide a number of specific examples of the impacts of climate change on this group of bacteria and their associated diseases, and discuss advanced strategies to improve our understanding of these emerging waterborne diseases through the integration of microbiological, genomic, epidemiological, climatic, and ocean sciences. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Mobile Microbiome

PubMed Central

Han, Y.W.; Wang, X.

2013-01-01

The link between oral infections and adverse systemic conditions has attracted much attention in the research community. Several mechanisms have been proposed, including spread of the oral infection due to transient bacteremia resulting in bacterial colonization in extra-oral sites, systemic injury by free toxins of oral pathogens, and systemic inflammation caused by soluble antigens of oral pathogens. Mounting evidence supports a major role of the systemic spread of oral commensals and pathogens to distant body sites causing extra-oral infections and inflammation. We review here the most recent findings on systemic infections and inflammation complicated by oral bacteria, including cardiovascular disease, adverse pregnancy outcomes, rheumatoid arthritis, inflammatory bowel disease and colorectal cancer, respiratory tract infections, and organ inflammations and abscesses. The recently identified virulence mechanisms of oral species Fusobacterium nucleatum, Porphyromonas gingivalis, Streptococcus mutans, and Campylobacter rectus are also reviewed. A pattern emerges indicating that only select subtype(s) of a given species, e.g., F. nucleatum subspecies animalis and polymorphum and S. mutans non-c serotypes, are prone to extra-oral translocation. These findings advocate the importance of identification and quantification of potential pathogens at the subtype levels for accurate prediction of disease potential. PMID:23625375

Background sequence characteristics influence the occurrence and severity of disease-causing mtDNA mutations

PubMed Central

Wei, Wei; Hudson, Gavin

2017-01-01

Inherited mitochondrial DNA (mtDNA) mutations have emerged as a common cause of human disease, with mutations occurring multiple times in the world population. The clinical presentation of three pathogenic mtDNA mutations is strongly associated with a background mtDNA haplogroup, but it is not clear whether this is limited to a handful of examples or is a more general phenomenon. To address this, we determined the characteristics of 30,506 mtDNA sequences sampled globally. After performing several quality control steps, we ascribed an established pathogenicity score to the major alleles for each sequence. The mean pathogenicity score for known disease-causing mutations was significantly different between mtDNA macro-haplogroups. Several mutations were observed across all haplogroup backgrounds, whereas others were only observed on specific clades. In some instances this reflected a founder effect, but in others, the mutation recurred but only within the same phylogenetic cluster. Sequence diversity estimates showed that disease-causing mutations were more frequent on young sequences, and genomes with two or more disease-causing mutations were more common than expected by chance. These findings implicate the mtDNA background more generally in recurrent mutation events that have been purified through natural selection in older populations. This provides an explanation for the low frequency of mtDNA disease reported in specific ethnic groups. PMID:29253894

Multiple rare opportunistic and pathogenic fungi in persistent foot skin infection.

PubMed

Chan, Giek Far; Sinniah, Sivaranjini; Idris, Tengku Idzzan Nadzirah Tengku; Puad, Mohamad Safwan Ahmad; Abd Rahman, Ahmad Zuhairi

2013-03-01

Persistent superficial skin infection caused by multiple fungi is rarely reported. Recently, a number of fungi, both opportunistic and persistent in nature were isolated from the foot skin of a 24-year old male in Malaysia. The fungi were identified as Candida parapsilosis, Rhodotorula mucilaginosa, Phoma spp., Debaryomyces hansenii, Acremonium spp., Aureobasidium pullulans and Aspergillus spp., This is the first report on these opportunistic strains were co-isolated from a healthy individual who suffered from persistent foot skin infection which was diagnosed as athlete's foot for more than 12 years. Among the isolated fungi, C. parapsilosis has been an increasingly common cause of skin infections. R. mucilaginosa and D. hansenii were rarely reported in cases of skin infection. A. pullulans, an emerging fungal pathogen was also being isolated in this case. Interestingly, it was noted that C. parapsilosis, R. mucilaginosa, D. hansenii and A. pullulans are among the common halophiles and this suggests the association of halotolerant fungi in causing persistent superficial skin infection. This discovery will shed light on future research to explore on effective treatment for inhibition of pathogenic halophiles as well as to understand the interaction of multiple fungi in the progress of skin infection.

A hypothetical model of host-pathogen interaction of Streptococcus suis in the gastro-intestinal tract

PubMed Central

Ferrando, Maria Laura; Schultsz, Constance

2016-01-01

ABSTRACT Streptococcus suis (SS) is a zoonotic pathogen that can cause systemic infection in pigs and humans. The ingestion of contaminated pig meat is a well-established risk factor for zoonotic S. suis disease. In our studies, we provide experimental evidence that S. suis is capable to translocate across the host gastro-intestinal tract (GIT) using in vivo and in vitro models. Hence, S. suis should be considered an emerging foodborne pathogen. In this addendum, we give an overview of the complex interactions between S. suis and host-intestinal mucosa which depends on the host origin, the serotype and genotype of S. suis, as well as the presence and expression of virulence factors involved in host-pathogen interaction. Finally, we propose a hypothetical model of S. suis interaction with the host-GIT taking in account differences in conditions between the porcine and human host. PMID:26900998

Nanomedicine as an emerging approach against intracellular pathogens

PubMed Central

Armstead, Andrea L; Li, Bingyun

2011-01-01

Diseases such as tuberculosis, hepatitis, and HIV/AIDS are caused by intracellular pathogens and are a major burden to the global medical community. Conventional treatments for these diseases typically consist of long-term therapy with a combination of drugs, which may lead to side effects and contribute to low patient compliance. The pathogens reside within intracellular compartments of the cell, which provide additional barriers to effective treatment. Therefore, there is a need for improved and more effective therapies for such intracellular diseases. This review will summarize, for the first time, the intracellular compartments in which pathogens can reside and discuss how nanomedicine has the potential to improve intracellular disease therapy by offering properties such as targeting, sustained drug release, and drug delivery to the pathogen’s intracellular location. The characteristics of nanomedicine may prove advantageous in developing improved or alternative therapies for intracellular diseases. PMID:22228996

Sexually transmitted infection and the evolution of serial monogamy

PubMed Central

McLeod, David V.; Day, Troy

2014-01-01

The selective forces shaping mating systems have long been of interest to biologists. One particular selective pressure that has received comparatively little attention is sexually transmitted infections (STIs). While it has been hypothesized that STIs could drive the evolutionary emergence of monogamy, there is little theoretical support. Here we use an evolutionary invasion analysis to determine what aspects of pathogen virulence and transmission are necessary for serial monogamy to evolve in a promiscuous population. We derive a biologically intuitive invasion condition in terms of population-specific quantities. From this condition, we obtain two main results. First, when pathogen virulence causes mortality rather than sterility, monogamy is more likely to evolve. Second, we find that at intermediate pathogen transmission rates, monogamy is the most selectively advantageous, whereas at high- and low-transmission rates, monogamy is generally selected against. As a result, it is possible for a pathogen to be highly virulent, yet for promiscuity to persist. PMID:25320174

A potentially fatal mix of herpes in zoos.

PubMed

Greenwood, Alex D; Tsangaras, Kyriakos; Ho, Simon Y W; Szentiks, Claudia A; Nikolin, Veljko M; Ma, Guanggang; Damiani, Armando; East, Marion L; Lawrenz, Arne; Hofer, Heribert; Osterrieder, Nikolaus

2012-09-25

Pathogens often have a limited host range, but some can opportunistically jump to new species. Anthropogenic activities that mix reservoir species with novel, hence susceptible, species can provide opportunities for pathogens to spread beyond their normal host range. Furthermore, rapid evolution can produce new pathogens by mechanisms such as genetic recombination. Zoos unintentionally provide pathogens with a high diversity of species from different continents and habitats assembled within a confined space. Institutions alert to the problem of pathogen spread to unexpected hosts can monitor the emergence of pathogens and take preventative measures. However, asymptomatic infections can result in the causative pathogens remaining undetected in their reservoir host. Furthermore, pathogen spread to unexpected hosts may remain undiagnosed if the outcome of infection is limited, as in the case of compromised fertility, or if more severe outcomes are restricted to less charismatic species that prompt only limited investigation. We illustrate this problem here with a recombinant zebra herpesvirus infecting charismatic species including zoo polar bears over at least four years. The virus may cause fatal encephalitis and infects at least five mammalian orders, apparently without requiring direct contact with infected animals. Copyright © 2012 Elsevier Ltd. All rights reserved.

First report of monomicrobial Candida parapsilosis necrotizing fasciitis.

PubMed

Gassiep, I; Douglas, J; Playford, E G

2016-10-01

Candida parapsilosis is an emerging pathogen worldwide. It commonly causes soft tissue infection; however, to our knowledge there has been no previous report of monomicrobial necrotizing soft tissue infection (NSTI) secondary to C. parapsilosis. We report the first case of NSTI caused by C. parapsilosis in an immunocompromised renal transplant patient, with the diagnosis proven both histologically and microbiologically. Our patient required aggressive surgical intervention and antifungal therapy, with postoperative survival at 90 days. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Onchocerca lupi causing ocular disease in two cats.

PubMed

Labelle, Amber L; Daniels, Joshua B; Dix, Michael; Labelle, Philippe

2011-09-01

Although canine ocular onchocerciasis has been well described as an emerging pathogen of dogs in Europe and North America over the past 20 years, there are no previous reports of feline ocular onchocerciasis. This report details the clinical, histopathologic, and molecular diagnosis of two domestic short hair cats residing in the United States infected with Onchocerca lupi causing episcleritis and orbital cellulitis. The results of this report suggest that O. lupi is a newly recognized disease of domestic cats. © 2011 American College of Veterinary Ophthalmologists.

Campylobacter jejuni—An Emerging Foodborne Pathogen

PubMed Central

Stern, Norman J.; Fields, Patricia I.; Swerdlow, David L.

1999-01-01

Campylobacter jejuni is the most commonly reported bacterial cause of foodborne infection in the United States. Adding to the human and economic costs are chronic sequelae associated with C. jejuni infection—Guillian-Barré syndrome and reactive arthritis. In addition, an increasing proportion of human infections caused by C. jejuni are resistant to antimicrobial therapy. Mishandling of raw poultry and consumption of undercooked poultry are the major risk factors for human campylobacteriosis. Efforts to prevent human illness are needed throughout each link in the food chain. PMID:10081669

Campylobacter jejuni--an emerging foodborne pathogen.

PubMed

Altekruse, S F; Stern, N J; Fields, P I; Swerdlow, D L

1999-01-01

Campylobacter jejuni is the most commonly reported bacterial cause of foodborne infection in the United States. Adding to the human and economic costs are chronic sequelae associated with C. jejuni infection--Guillian-Barré syndrome and reactive arthritis. In addition, an increasing proportion of human infections caused by C. jejuni are resistant to antimicrobial therapy. Mishandling of raw poultry and consumption of undercooked poultry are the major risk factors for human campylobacteriosis. Efforts to prevent human illness are needed throughout each link in the food chain.

Combating Pathogenic Microorganisms Using Plant-Derived Antimicrobials: A Minireview of the Mechanistic Basis

PubMed Central

Upadhyaya, Indu; Kollanoor-Johny, Anup

2014-01-01

The emergence of antibiotic resistance in pathogenic bacteria has led to renewed interest in exploring the potential of plant-derived antimicrobials (PDAs) as an alternative therapeutic strategy to combat microbial infections. Historically, plant extracts have been used as a safe, effective, and natural remedy for ailments and diseases in traditional medicine. Extensive research in the last two decades has identified a plethora of PDAs with a wide spectrum of activity against a variety of fungal and bacterial pathogens causing infections in humans and animals. Active components of many plant extracts have been characterized and are commercially available; however, research delineating the mechanistic basis of their antimicrobial action is scanty. This review highlights the potential of various plant-derived compounds to control pathogenic bacteria, especially the diverse effects exerted by plant compounds on various virulence factors that are critical for pathogenicity inside the host. In addition, the potential effect of PDAs on gut microbiota is discussed. PMID:25298964

Correlation between Detection of a Plasmid and High-Level Virulence of Vibrio nigripulchritudo, a Pathogen of the Shrimp Litopenaeus stylirostris▿

PubMed Central

Reynaud, Yann; Saulnier, Denis; Mazel, Didier; Goarant, Cyrille; Le Roux, Frédérique

2008-01-01

Vibrio nigripulchritudo, the etiological agent of Litopenaeus stylirostris summer syndrome, is responsible for mass mortalities of shrimp in New Caledonia. Epidemiological studies led to the suggestion that this disease is caused by an emergent group of pathogenic strains. Genomic subtractive hybridization was carried out between two isolates exhibiting low and high virulence. Our subtraction library was constituted of 521 specific fragments; 55 of these were detected in all virulent isolates from our collection (n = 32), and 13 were detected only in the isolates demonstrating the highest pathogenicity (n = 19), suggesting that they could be used as genetic markers for high virulence capacity. Interestingly, 10 of these markers are carried by a replicon of 11.2 kbp that contains sequences highly similar to those of a plasmid detected in Vibrio shilonii, a coral pathogen. The detection of this plasmid was correlated with the highest pathogenicity status of the isolates from our collection. The origin and consequence of this plasmid acquisition are discussed. PMID:18359828

Transient virulence of emerging pathogens.

PubMed

Bolker, Benjamin M; Nanda, Arjun; Shah, Dharmini

2010-05-06

Should emerging pathogens be unusually virulent? If so, why? Existing theories of virulence evolution based on a tradeoff between high transmission rates and long infectious periods imply that epidemic growth conditions will select for higher virulence, possibly leading to a transient peak in virulence near the beginning of an epidemic. This transient selection could lead to high virulence in emerging pathogens. Using a simple model of the epidemiological and evolutionary dynamics of emerging pathogens, along with rough estimates of parameters for pathogens such as severe acute respiratory syndrome, West Nile virus and myxomatosis, we estimated the potential magnitude and timing of such transient virulence peaks. Pathogens that are moderately evolvable, highly transmissible, and highly virulent at equilibrium could briefly double their virulence during an epidemic; thus, epidemic-phase selection could contribute significantly to the virulence of emerging pathogens. In order to further assess the potential significance of this mechanism, we bring together data from the literature for the shapes of tradeoff curves for several pathogens (myxomatosis, HIV, and a parasite of Daphnia) and the level of genetic variation for virulence for one (myxomatosis). We discuss the need for better data on tradeoff curves and genetic variance in order to evaluate the plausibility of various scenarios of virulence evolution.

Transient virulence of emerging pathogens

PubMed Central

Bolker, Benjamin M.; Nanda, Arjun; Shah, Dharmini

2010-01-01

Should emerging pathogens be unusually virulent? If so, why? Existing theories of virulence evolution based on a tradeoff between high transmission rates and long infectious periods imply that epidemic growth conditions will select for higher virulence, possibly leading to a transient peak in virulence near the beginning of an epidemic. This transient selection could lead to high virulence in emerging pathogens. Using a simple model of the epidemiological and evolutionary dynamics of emerging pathogens, along with rough estimates of parameters for pathogens such as severe acute respiratory syndrome, West Nile virus and myxomatosis, we estimated the potential magnitude and timing of such transient virulence peaks. Pathogens that are moderately evolvable, highly transmissible, and highly virulent at equilibrium could briefly double their virulence during an epidemic; thus, epidemic-phase selection could contribute significantly to the virulence of emerging pathogens. In order to further assess the potential significance of this mechanism, we bring together data from the literature for the shapes of tradeoff curves for several pathogens (myxomatosis, HIV, and a parasite of Daphnia) and the level of genetic variation for virulence for one (myxomatosis). We discuss the need for better data on tradeoff curves and genetic variance in order to evaluate the plausibility of various scenarios of virulence evolution. PMID:19864267

In Vitro Emergence of High Persistence upon Periodic Aminoglycoside Challenge in the ESKAPE Pathogens

PubMed Central

Verstraeten, Natalie; Fauvart, Maarten

2016-01-01

Health care-associated infections present a major threat to modern medical care. Six worrisome nosocomial pathogens—Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.—are collectively referred to as the “ESKAPE bugs.” They are notorious for extensive multidrug resistance, yet persistence, or the phenotypic tolerance displayed by a variant subpopulation, remains underappreciated in these pathogens. Importantly, persistence can prevent eradication of antibiotic-sensitive bacterial populations and is thought to act as a catalyst for the development of genetic resistance. Concentration- and time-dependent aminoglycoside killing experiments were used to investigate persistence in the ESKAPE pathogens. Additionally, a recently developed method for the experimental evolution of persistence was employed to investigate adaptation to high-dose, extended-interval aminoglycoside therapy in vitro. We show that ESKAPE pathogens exhibit biphasic killing kinetics, indicative of persister formation. In vitro cycling between aminoglycoside killing and persister cell regrowth, evocative of clinical high-dose extended-interval therapy, caused a 37- to 213-fold increase in persistence without the emergence of resistance. Increased persistence also manifested in biofilms and provided cross-tolerance to different clinically important antibiotics. Together, our results highlight a possible drawback of intermittent, high-dose antibiotic therapy and suggest that clinical diagnostics might benefit from taking into account persistence. PMID:27185802

Host and pathogen ecology drive the seasonal dynamics of a fungal disease, white-nose syndrome.

PubMed

Langwig, Kate E; Frick, Winifred F; Reynolds, Rick; Parise, Katy L; Drees, Kevin P; Hoyt, Joseph R; Cheng, Tina L; Kunz, Thomas H; Foster, Jeffrey T; Kilpatrick, A Marm

2015-01-22

Seasonal patterns in pathogen transmission can influence the impact of disease on populations and the speed of spatial spread. Increases in host contact rates or births drive seasonal epidemics in some systems, but other factors may occasionally override these influences. White-nose syndrome, caused by the emerging fungal pathogen Pseudogymnoascus destructans, is spreading across North America and threatens several bat species with extinction. We examined patterns and drivers of seasonal transmission of P. destructans by measuring infection prevalence and pathogen loads in six bat species at 30 sites across the eastern United States. Bats became transiently infected in autumn, and transmission spiked in early winter when bats began hibernating. Nearly all bats in six species became infected by late winter when infection intensity peaked. In summer, despite high contact rates and a birth pulse, most bats cleared infections and prevalence dropped to zero. These data suggest the dominant driver of seasonal transmission dynamics was a change in host physiology, specifically hibernation. Our study is the first, to the best of our knowledge, to describe the seasonality of transmission in this emerging wildlife disease. The timing of infection and fungal growth resulted in maximal population impacts, but only moderate rates of spatial spread. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Host and pathogen ecology drive the seasonal dynamics of a fungal disease, white-nose syndrome

PubMed Central

Langwig, Kate E.; Frick, Winifred F.; Reynolds, Rick; Parise, Katy L.; Drees, Kevin P.; Hoyt, Joseph R.; Cheng, Tina L.; Kunz, Thomas H.; Foster, Jeffrey T.; Kilpatrick, A. Marm

2015-01-01

Seasonal patterns in pathogen transmission can influence the impact of disease on populations and the speed of spatial spread. Increases in host contact rates or births drive seasonal epidemics in some systems, but other factors may occasionally override these influences. White-nose syndrome, caused by the emerging fungal pathogen Pseudogymnoascus destructans, is spreading across North America and threatens several bat species with extinction. We examined patterns and drivers of seasonal transmission of P. destructans by measuring infection prevalence and pathogen loads in six bat species at 30 sites across the eastern United States. Bats became transiently infected in autumn, and transmission spiked in early winter when bats began hibernating. Nearly all bats in six species became infected by late winter when infection intensity peaked. In summer, despite high contact rates and a birth pulse, most bats cleared infections and prevalence dropped to zero. These data suggest the dominant driver of seasonal transmission dynamics was a change in host physiology, specifically hibernation. Our study is the first, to the best of our knowledge, to describe the seasonality of transmission in this emerging wildlife disease. The timing of infection and fungal growth resulted in maximal population impacts, but only moderate rates of spatial spread. PMID:25473016

The emergence and outbreak of multidrug-resistant typhoid fever in China.

PubMed

Yan, Meiying; Li, Xinlan; Liao, Qiaohong; Li, Fang; Zhang, Jing; Kan, Biao

2016-06-22

Typhoid fever remains a severe public health problem in developing countries. The emergence of resistant typhoid, particularly multidrug-resistant typhoid infections, highlights the necessity of monitoring the resistance characteristics of this invasive pathogen. In this study, we report a typhoid fever outbreak caused by multidrug-resistant Salmonella enterica serovar Typhi strains with an ACSSxtT pattern. Resistance genes conferring these phenotypes were harbored by a large conjugative plasmid, which increases the threat of Salmonella Typhi and thus requires close surveillance for dissemination of strains containing such genes.

The emergence and outbreak of multidrug-resistant typhoid fever in China

PubMed Central

Yan, Meiying; Li, Xinlan; Liao, Qiaohong; Li, Fang; Zhang, Jing; Kan, Biao

2016-01-01

Typhoid fever remains a severe public health problem in developing countries. The emergence of resistant typhoid, particularly multidrug-resistant typhoid infections, highlights the necessity of monitoring the resistance characteristics of this invasive pathogen. In this study, we report a typhoid fever outbreak caused by multidrug-resistant Salmonella enterica serovar Typhi strains with an ACSSxtT pattern. Resistance genes conferring these phenotypes were harbored by a large conjugative plasmid, which increases the threat of Salmonella Typhi and thus requires close surveillance for dissemination of strains containing such genes. PMID:27329848

Prediction and prevention of the next pandemic zoonosis

PubMed Central

Morse, Stephen S; Mazet, Jonna A K; Woolhouse, Mark; Parrish, Colin R; Carroll, Dennis; Karesh, William B; Zambrana-Torrelio, Carlos; Lipkin, W Ian; Daszak, Peter

2013-01-01

Most pandemics—eg, HIV/AIDS, severe acute respiratory syndrome, pandemic influenza—originate in animals, are caused by viruses, and are driven to emerge by ecological, behavioural, or socioeconomic changes. Despite their substantial effects on global public health and growing understanding of the process by which they emerge, no pandemic has been predicted before infecting human beings. We review what is known about the pathogens that emerge, the hosts that they originate in, and the factors that drive their emergence. We discuss challenges to their control and new efforts to predict pandemics, target surveillance to the most crucial interfaces, and identify prevention strategies. New mathematical modelling, diagnostic, communications, and informatics technologies can identify and report hitherto unknown microbes in other species, and thus new risk assessment approaches are needed to identify microbes most likely to cause human disease. We lay out a series of research and surveillance opportunities and goals that could help to overcome these challenges and move the global pandemic strategy from response to pre-emption. PMID:23200504

Nanoparticles as potential new generation broad spectrum antimicrobial agents.

PubMed

Yah, Clarence S; Simate, Geoffrey S

2015-09-02

The rapid emergence of antimicrobial resistant strains to conventional antimicrobial agents has complicated and prolonged infection treatment and increased mortality risk globally. Furthermore, some of the conventional antimicrobial agents are unable to cross certain cell membranes thus, restricting treatment of intracellular pathogens. Therefore, the disease-causing-organisms tend to persist in these cells. However, the emergence of nanoparticle (NP) technology has come with the promising broad spectrum NP-antimicrobial agents due to their vast physiochemical and functionalization properties. In fact, NP-antimicrobial agents are able to unlock the restrictions experienced by conventional antimicrobial agents. This review discusses the status quo of NP-antimicrobial agents as potent broad spectrum antimicrobial agents, sterilization and wound healing agents, and sustained inhibitors of intracellular pathogens. Indeed, the perspective of developing potent NP-antimicrobial agents that carry multiple-functionality will revolutionize clinical medicine and play a significant role in alleviating disease burden.

Quantitative proteomics to study carbapenem resistance in Acinetobacter baumannii

PubMed Central

Tiwari, Vishvanath; Tiwari, Monalisa

2014-01-01

Acinetobacter baumannii is an opportunistic pathogen causing pneumonia, respiratory infections and urinary tract infections. The prevalence of this lethal pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source. Moreover it resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. Resistance against carbapenem has emerged in Acinetobacter baumannii which can create significant health problems and is responsible for high morbidity and mortality. With the development of quantitative proteomics, a considerable progress has been made in the study of carbapenem resistance of Acinetobacter baumannii. Recent updates showed that quantitative proteomics has now emerged as an important tool to understand the carbapenem resistance mechanism in Acinetobacter baumannii. Present review also highlights the complementary nature of different quantitative proteomic methods used to study carbapenem resistance and suggests to combine multiple proteomic methods for understanding the response to antibiotics by Acinetobacter baumannii. PMID:25309531

Molecular characterization of avian influenza H5N1 virus in Egypt and the emergence of a novel endemic subclade

PubMed Central

El-Shesheny, Rabeh; Kandeil, Ahmed; Bagato, Ola; Maatouq, Asmaa M.; Moatasim, Yassmin; Rubrum, Adam; Song, Min-Suk; Webby, Richard J.

2014-01-01

Clade 2.2 highly pathogenic H5N1 viruses have been in continuous circulation in Egyptian poultry since 2006. Their persistence caused significant genetic drift that led to the reclassification of these viruses into subclades 2.2.1 and 2.2.1.1. Here, we conducted full-genome sequence and phylogenetic analyses of 45 H5N1 isolated during 2006–2013 through systematic surveillance in Egypt, and 53 viruses that were sequenced previously and available in the public domain. Results indicated that H5N1 viruses in Egypt continue to evolve and a new distinct cluster has emerged. Mutations affecting viral virulence, pathogenicity, transmission, receptor-binding preference and drug resistance were studied. In light of our findings that H5N1 in Egypt continues to evolve, surveillance and molecular studies need to be sustained. PMID:24722680

Future potential distribution of the emerging amphibian chytrid fungus under anthropogenic climate change.

PubMed

Rödder, Dennis; Kielgast, Jos; Lötters, Stefan

2010-11-01

Anthropogenic climate change poses a major threat to global biodiversity with a potential to alter biological interactions at all spatial scales. Amphibians are the most threatened vertebrates and have been subject to increasing conservation attention over the past decade. A particular concern is the pandemic emergence of the parasitic chytrid fungus Batrachochytrium dendrobatidis, which has been identified as the cause of extremely rapid large-scale declines and species extinctions. Experimental and observational studies have demonstrated that the host-pathogen system is strongly influenced by climatic parameters and thereby potentially affected by climate change. Herein we project a species distribution model of the pathogen onto future climatic scenarios generated by the IPCC to examine their potential implications on the pandemic. Results suggest that predicted anthropogenic climate change may reduce the geographic range of B. dendrobatidis and its potential influence on amphibian biodiversity.

Evaluation of Argentinean Bird Species as Amplifying Hosts for St. Louis Encephalitis Virus (Flavivirus, Flaviviridae).

PubMed

Díaz, Adrián; Flores, Fernando S; Quaglia, Agustín I; Contigiani, Marta S

2018-05-14

St.Louis encephalitis virus (SLEV) is an emerging human pathogen flavivirus in Argentina. Recently, it has reemerged in the United States. We evaluated the role as amplifying host of six resident bird species and analyzed their capacity as host during the 2005 encephalitis outbreak of SLEV in Córdoba. Eared dove, picui ground dove, and house sparrow were the three species with highest host competence index. At a city level, eared doves and picui ground doves were the most important amplifying hosts during the 2005 SLEV human outbreak in Córdoba city. This finding highlighted important differences in the SLEV ecology between Argentina and the United States. Characterizing and evaluating the SLEV hosts contribute to our knowledge about its ecology and could help us to understand the causes that promote its emergence as a human pathogen in South America.

Broad-spectrum antivirals against viral fusion

PubMed Central

Vigant, Frederic; Santos, Nuno C.; Lee, Benhur

2015-01-01

Effective antivirals have been developed against specific viruses, such as HIV, Hepatitis C virus and influenza virus. This ‘one bug–one drug’ approach to antiviral drug development can be successful, but it may be inadequate for responding to an increasing diversity of viruses that cause significant diseases in humans. The majority of viral pathogens that cause emerging and re-emerging infectious diseases are membrane-enveloped viruses, which require the fusion of viral and cell membranes for virus entry. Therefore, antivirals that target the membrane fusion process represent new paradigms for broad-spectrum antiviral discovery. In this Review, we discuss the mechanisms responsible for the fusion between virus and cell membranes and explore how broad-spectrum antivirals target this process to prevent virus entry. PMID:26075364

Elucidation of Bacterial Pneumonia-Causing Pathogens in Patients with Respiratory Viral Infection

PubMed Central

Jung, Hwa Sik; Kang, Byung Ju; Ra, Seung Won; Seo, Kwang Won; Jegal, Yangjin; Jun, Jae-Bum; Jung, Jiwon; Jeong, Joseph; Jeon, Hee-Jeong; Ahn, Jae-Sung

2017-01-01

Background Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. Methods Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. Results A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ≥16 years, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. Conclusion The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia. PMID:28905531

Surgical treatment for pulmonary aspergilloma in seventeenth years old female: case report

NASA Astrophysics Data System (ADS)

Yanni, G. N.; Lubis, M.; Yoel, C.

2018-03-01

Aspergillosis is defined as a mycosis group caused by various pathogenic fungi of the Aspergillus genus. Aspergillus has more than 900 species that cause infection in human. The most common Aspergillus species that cause infection is Aspergillus fumigatus, about 90%. Other species, Aspergillus flavus, about 10% cause invasive disease. Have been reported a young girl 17-year-8-month-old woman was admitted to emergency with complaints of coughing up blood. The patient has diagnosed an aspergilloma and treated with thoracotomy bi-lobectomy right lower lung based on thorax scan. The patient took Fluconazole and surgical bilobectomyfor treated the aspergilloma and got improvement.

Predators indirectly control vector-borne disease: linking predator-prey and host-pathogen models.

PubMed

Moore, Sean M; Borer, Elizabeth T; Hosseini, Parviez R

2010-01-06

Pathogens transmitted by arthropod vectors are common in human populations, agricultural systems and natural communities. Transmission of these vector-borne pathogens depends on the population dynamics of the vector species as well as its interactions with other species within the community. In particular, predation may be sufficient to control pathogen prevalence indirectly via the vector. To examine the indirect effect of predators on vectored-pathogen dynamics, we developed a theoretical model that integrates predator-prey and host-pathogen theory. We used this model to determine whether predation can prevent pathogen persistence or alter the stability of host-pathogen dynamics. We found that, in the absence of predation, pathogen prevalence in the host increases with vector fecundity, whereas predation on the vector causes pathogen prevalence to decline, or even become extinct, with increasing vector fecundity. We also found that predation on a vector may drastically slow the initial spread of a pathogen. The predator can increase host abundance indirectly by reducing or eliminating infection in the host population. These results highlight the importance of studying interactions that, within the greater community, may alter our predictions when studying disease dynamics. From an applied perspective, these results also suggest situations where an introduced predator or the natural enemies of a vector may slow the rate of spread of an emerging vector-borne pathogen.

Photobacterium damselae subsp. damselae, an Emerging Fish Pathogen in the Black Sea: Evidence of a Multiclonal Origin

PubMed Central

Terceti, Mateus S.; Ogut, Hamdi

2016-01-01

ABSTRACT Photobacterium damselae subsp. damselae is considered to be an emerging pathogen of marine fish of importance in aquaculture, with a notable increase in its geographical distribution during the last several years. In this study, we carried out for the first time to our knowledge a genetic and pathobiological characterization of 14 strains isolated from sea bass (Dicentrarchus labrax) reared in the Southeastern Black Sea, where high mortalities were observed at two aquaculture farms during the summer and autumn of 2011. Heterogeneity was evidenced among strains in phenotypical traits, such as sucrose fermentation, motility, and hemolysis. Although 11 of 14 isolates were hemolytic, we found that all of the isolates lacked the pPHDD1 virulence plasmid that encodes the phospholipase-D damselysin (Dly) and the pore-forming toxin PhlyP, two hemolysins previously reported to constitute major virulence factors for turbot. Subsequent PCR and sequencing analyses demonstrated that the 11 hemolytic isolates harbored a complete hlyAch gene, a chromosome I-borne gene that encodes HlyAch hemolysin, whereas the three nonhemolytic isolates contained hlyAch pseudogenes caused by insertion sequence elements. Virulence challenges with two representative strains revealed that, albeit less virulent than the pPHDD1-harboring strain RM-71, the plasmidless hlyAch-positive and hlyAch-negative Black Sea isolates were pathogenic for sea bass. A phylogenetic analysis based on the toxR gene sequence uncovered a greater diversity in the isolates, indicating that the presence of this pathogen in the Black Sea was not caused by the introduction and spread of a single virulent clone but by the proliferation of different clones. IMPORTANCE The geographical distribution of marine bacterial pathogens is undergoing a worldwide increase. In particular, bacteria of the group vibrios are increasingly being isolated as the causative agents of disease in novel species of cultivated fish in areas where they had not been previously reported. Here we characterize for the first time to our knowledge a collection of isolates of the fish and human pathogen Photobacterium damselae subsp. damselae from diseased sea bass reared in the Black Sea. We uncovered great genetic diversity in the Black Sea isolates of this pathogen, suggesting a multiclonal origin. We also demonstrate for the first time that these isolates bear pathogenic potential for sea bass cultures by virulence challenges. PMID:27084008

Rapid Molecular Detection Methods for Arboviruses of Livestock of Importance to Northern Europe

PubMed Central

Johnson, Nicholas; Voller, Katja; Phipps, L. Paul; Mansfield, Karen; Fooks, Anthony R.

2012-01-01

Arthropod-borne viruses (arboviruses) have been responsible for some of the most explosive epidemics of emerging infectious diseases over the past decade. Their impact on both human and livestock populations has been dramatic. The early detection either through surveillance or diagnosis of virus will be a critical feature in responding and resolving the emergence of such epidemics in the future. Although some of the most important emerging arboviruses are human pathogens, this paper aims to highlight those diseases that primarily affect livestock, although many are zoonotic and some occasionally cause human mortality. This paper also highlights the molecular detection methods specific to each virus and identifies those emerging diseases for which a rapid detection methods are not yet developed. PMID:22219660

Spontaneous bacterial and fungal infections in genetically engineered mice: Is Escherichia coli an emerging pathogen in laboratory mouse?

PubMed

Benga, Laurentiu; Benten, W Peter M; Engelhardt, Eva; Gougoula, Christina; Sager, Martin

2015-01-01

The impact of particular microbes on genetically engineered mice depends on the genotype and the environment. Infections resulting in clinical disease have an obvious impact on animal welfare and experimentation. In this study, we investigated the bacterial and fungal aetiology of spontaneous clinical disease of infectious origin among the genetically engineered mice from our institution in relation to their genotype. A total of 63 mice belonging to 33 different mice strains, from severe immunodeficient to wild-type, were found to display infections as the primary cause leading to their euthanasia. The necropsies revealed abscesses localized subcutaneously as well as in the kidney, preputial glands, seminal vesicles, in the uterus, umbilicus or in the lung. In addition, pneumonia, endometritis and septicaemia cases were recorded. Escherichia coli was involved in 21 of 44 (47.72%) of the lesions of bacterial origin, whereas [Pasteurella] pneumotropica was isolated from 19 of 44 (43.18%) cases. The infections with the two agents mentioned above included three cases of mixed infection with both pathogens. Staphylococcus aureus was considered responsible for five of 44 (11.36%) cases whereas Enterobacter cloacae was found to cause lesions in two of 44 (4.54%) mice. Overall, 16 of the 44 (36.36%) cases of bacterial aetiology affected genetically engineered mice without any explicit immunodeficiency or wild-type strains. The remaining 19 cases of interstitial pneumonia were caused by Pneumocystis murina. In conclusion, the susceptibility of genetically modified mice to opportunistic infections has to be regarded with precaution, regardless of the type of genetic modification performed. Beside the classical opportunists, such as [Pasteurella] pneumotropica and Staphylococcus aureus, Escherichia coli should as well be closely monitored to evaluate whether it represents an emerging pathogen in the laboratory mouse.

Single Assay for Simultaneous Detection and Differential Identification of Human and Avian Influenza Virus Types, Subtypes, and Emergent Variants

PubMed Central

Metzgar, David; Myers, Christopher A.; Russell, Kevin L.; Faix, Dennis; Blair, Patrick J.; Brown, Jason; Vo, Scott; Swayne, David E.; Thomas, Colleen; Stenger, David A.; Lin, Baochuan; Malanoski, Anthony P.; Wang, Zheng; Blaney, Kate M.; Long, Nina C.; Schnur, Joel M.; Saad, Magdi D.; Borsuk, Lisa A.; Lichanska, Agnieszka M.; Lorence, Matthew C.; Weslowski, Brian; Schafer, Klaus O.; Tibbetts, Clark

2010-01-01

For more than four decades the cause of most type A influenza virus infections of humans has been attributed to only two viral subtypes, A/H1N1 or A/H3N2. In contrast, avian and other vertebrate species are a reservoir of type A influenza virus genome diversity, hosting strains representing at least 120 of 144 combinations of 16 viral hemagglutinin and 9 viral neuraminidase subtypes. Viral genome segment reassortments and mutations emerging within this reservoir may spawn new influenza virus strains as imminent epidemic or pandemic threats to human health and poultry production. Traditional methods to detect and differentiate influenza virus subtypes are either time-consuming and labor-intensive (culture-based) or remarkably insensitive (antibody-based). Molecular diagnostic assays based upon reverse transcriptase-polymerase chain reaction (RT-PCR) have short assay cycle time, and high analytical sensitivity and specificity. However, none of these diagnostic tests determine viral gene nucleotide sequences to distinguish strains and variants of a detected pathogen from one specimen to the next. Decision-quality, strain- and variant-specific pathogen gene sequence information may be critical for public health, infection control, surveillance, epidemiology, or medical/veterinary treatment planning. The Resequencing Pathogen Microarray (RPM-Flu) is a robust, highly multiplexed and target gene sequencing-based alternative to both traditional culture- or biomarker-based diagnostic tests. RPM-Flu is a single, simultaneous differential diagnostic assay for all subtype combinations of type A influenza viruses and for 30 other viral and bacterial pathogens that may cause influenza-like illness. These other pathogen targets of RPM-Flu may co-infect and compound the morbidity and/or mortality of patients with influenza. The informative specificity of a single RPM-Flu test represents specimen-specific viral gene sequences as determinants of virus type, A/HN subtype, virulence, host-range, and resistance to antiviral agents. PMID:20140251

Single assay for simultaneous detection and differential identification of human and avian influenza virus types, subtypes, and emergent variants.

PubMed

Metzgar, David; Myers, Christopher A; Russell, Kevin L; Faix, Dennis; Blair, Patrick J; Brown, Jason; Vo, Scott; Swayne, David E; Thomas, Colleen; Stenger, David A; Lin, Baochuan; Malanoski, Anthony P; Wang, Zheng; Blaney, Kate M; Long, Nina C; Schnur, Joel M; Saad, Magdi D; Borsuk, Lisa A; Lichanska, Agnieszka M; Lorence, Matthew C; Weslowski, Brian; Schafer, Klaus O; Tibbetts, Clark

2010-02-03

For more than four decades the cause of most type A influenza virus infections of humans has been attributed to only two viral subtypes, A/H1N1 or A/H3N2. In contrast, avian and other vertebrate species are a reservoir of type A influenza virus genome diversity, hosting strains representing at least 120 of 144 combinations of 16 viral hemagglutinin and 9 viral neuraminidase subtypes. Viral genome segment reassortments and mutations emerging within this reservoir may spawn new influenza virus strains as imminent epidemic or pandemic threats to human health and poultry production. Traditional methods to detect and differentiate influenza virus subtypes are either time-consuming and labor-intensive (culture-based) or remarkably insensitive (antibody-based). Molecular diagnostic assays based upon reverse transcriptase-polymerase chain reaction (RT-PCR) have short assay cycle time, and high analytical sensitivity and specificity. However, none of these diagnostic tests determine viral gene nucleotide sequences to distinguish strains and variants of a detected pathogen from one specimen to the next. Decision-quality, strain- and variant-specific pathogen gene sequence information may be critical for public health, infection control, surveillance, epidemiology, or medical/veterinary treatment planning. The Resequencing Pathogen Microarray (RPM-Flu) is a robust, highly multiplexed and target gene sequencing-based alternative to both traditional culture- or biomarker-based diagnostic tests. RPM-Flu is a single, simultaneous differential diagnostic assay for all subtype combinations of type A influenza viruses and for 30 other viral and bacterial pathogens that may cause influenza-like illness. These other pathogen targets of RPM-Flu may co-infect and compound the morbidity and/or mortality of patients with influenza. The informative specificity of a single RPM-Flu test represents specimen-specific viral gene sequences as determinants of virus type, A/HN subtype, virulence, host-range, and resistance to antiviral agents.

Pathobiological features of a novel, highly pathogenic avian influenza A(H5N8) virus

PubMed Central

Kim, Young-Il; Pascua, Philippe Noriel Q; Kwon, Hyeok-Il; Lim, Gyo-Jin; Kim, Eun-Ha; Yoon, Sun-Woo; Park, Su-Jin; Kim, Se Mi; Choi, Eun-Ji; Si, Young-Jae; Lee, Ok-Jun; Shim, Woo-Sub; Kim, Si-Wook; Mo, In-Pil; Bae, Yeonji; Lim, Yong Taik; Sung, Moon Hee; Kim, Chul-Joong; Webby, Richard J; Webster, Robert G; Choi, Young Ki

2014-01-01

The endemicity of highly pathogenic avian influenza (HPAI) A(H5N1) viruses in Asia has led to the generation of reassortant H5 strains with novel gene constellations. A newly emerged HPAI A(H5N8) virus caused poultry outbreaks in the Republic of Korea in 2014. Because newly emerging high-pathogenicity H5 viruses continue to pose public health risks, it is imperative that their pathobiological properties be examined. Here, we characterized A/mallard duck/Korea/W452/2014 (MDk/W452(H5N8)), a representative virus, and evaluated its pathogenic and pandemic potential in various animal models. We found that MDk/W452(H5N8), which originated from the reassortment of wild bird viruses harbored by migratory waterfowl in eastern China, replicated systemically and was lethal in chickens, but appeared to be attenuated, albeit efficiently transmitted, in ducks. Despite predominant attachment to avian-like virus receptors, MDk/W452(H5N8) also exhibited detectable human virus-like receptor binding and replicated in human respiratory tract tissues. In mice, MDk/W452(H5N8) was moderately pathogenic and had limited tissue tropism relative to previous HPAI A(H5N1) viruses. It also induced moderate nasal wash titers in inoculated ferrets; additionally, it was recovered in extrapulmonary tissues and one of three direct-contact ferrets seroconverted without shedding. Moreover, domesticated cats appeared to be more susceptible than dogs to virus infection. With their potential to become established in ducks, continued circulation of A(H5N8) viruses could alter the genetic evolution of pre-existing avian poultry strains. Overall, detailed virological investigation remains a necessity given the capacity of H5 viruses to evolve to cause human illness with few changes in the viral genome. PMID:26038499

Pathobiological features of a novel, highly pathogenic avian influenza A(H5N8) virus.

PubMed

Kim, Young-Il; Pascua, Philippe Noriel Q; Kwon, Hyeok-Il; Lim, Gyo-Jin; Kim, Eun-Ha; Yoon, Sun-Woo; Park, Su-Jin; Kim, Se Mi; Choi, Eun-Ji; Si, Young-Jae; Lee, Ok-Jun; Shim, Woo-Sub; Kim, Si-Wook; Mo, In-Pil; Bae, Yeonji; Lim, Yong Taik; Sung, Moon Hee; Kim, Chul-Joong; Webby, Richard J; Webster, Robert G; Choi, Young Ki

2014-10-01

The endemicity of highly pathogenic avian influenza (HPAI) A(H5N1) viruses in Asia has led to the generation of reassortant H5 strains with novel gene constellations. A newly emerged HPAI A(H5N8) virus caused poultry outbreaks in the Republic of Korea in 2014. Because newly emerging high-pathogenicity H5 viruses continue to pose public health risks, it is imperative that their pathobiological properties be examined. Here, we characterized A/mallard duck/Korea/W452/2014 (MDk/W452(H5N8)), a representative virus, and evaluated its pathogenic and pandemic potential in various animal models. We found that MDk/W452(H5N8), which originated from the reassortment of wild bird viruses harbored by migratory waterfowl in eastern China, replicated systemically and was lethal in chickens, but appeared to be attenuated, albeit efficiently transmitted, in ducks. Despite predominant attachment to avian-like virus receptors, MDk/W452(H5N8) also exhibited detectable human virus-like receptor binding and replicated in human respiratory tract tissues. In mice, MDk/W452(H5N8) was moderately pathogenic and had limited tissue tropism relative to previous HPAI A(H5N1) viruses. It also induced moderate nasal wash titers in inoculated ferrets; additionally, it was recovered in extrapulmonary tissues and one of three direct-contact ferrets seroconverted without shedding. Moreover, domesticated cats appeared to be more susceptible than dogs to virus infection. With their potential to become established in ducks, continued circulation of A(H5N8) viruses could alter the genetic evolution of pre-existing avian poultry strains. Overall, detailed virological investigation remains a necessity given the capacity of H5 viruses to evolve to cause human illness with few changes in the viral genome.

Epidemiology of the Ebola Virus: Facts and Hypotheses.

PubMed

Portela Câmara F

1998-12-01

Marburg and Ebola viruses are emerging pathogens recognized since 1967, and in 1976, when they were first identified. These viruses are the only members of the Filoviridae family. They cause severe, frequently fatal, hemorrhagic fever. Each genus includes some serotypes with the distinctive characteristics to cause high mortality rate during outbreaks. The Ebola-Zaire subtype is the most lethal variant. The epidemiology of human pathogenic filovirus is reviewed in this paper considering the most relevant facts. Primary human cases arise probably through close contact with infected primates. This point may be the key to preventing the introduction of these viruses in human populations. Once introduced in humans, the infection may spread through close contact with infected individuals or their body fluids, particularly in hospital environments. A main feature of filovirus outbreaks is the occurrence of cycles of secondary infection.

Epidemiology of Acute Febrile Illness in Latin America.

PubMed

Moreira, José; Bressan, Clarisse S; Brasil, Patricia; Siqueira, Andre M

2018-05-16

The causes of acute febrile illness (AFI) in Latin America (LA) are diverse and its complexity increase as the proportion of fever due to malaria decreases as control and new pathogens emerge in the region. In this context, it is important to shed light over the gaps on the epidemiological characteristics and the geographic range for many AFI aetiologies. To review studies on community-acquired fever etiology other than malaria in LA, and to highlight knowledge gaps and challenges needing further investigation. PubMed from 2012 to April 2018 CONTENT: We found 17 eligible studies describing 13,539 patients. The median number of pathogens tested per individuals was 3.5, with range varying from 2 to 17. A causative pathogen could be determined for 6,661 (49.2%) individuals. The most frequently reported pathogen during the study periods was dengue virus (DENV) (14 studies), followed by Chikungunya virus (9) and Zika virus (7). Among the studies reporting concurrent infections, 296 patients (2.2%) were found to have co-infections. In-hospital mortality was reported in 8 (47%) studies, ranging between 0-18%. DENV is the febrile illness most frequently reported, reflecting its importance, while CHIKV and ZIKV present increasing trends since its emergence in the region. Studies with systematic and harmonized approach for detection of multiple pathogens are needed and would probably reveal a higher burden of neglected pathogens such as Rickettsia spp. and arenaviruses. The lack of point-of-care tests and harmonized approach limits the care provided by health professionals and the efficacy of surveillance for AFI in the region. Copyright © 2018. Published by Elsevier Ltd.

The emergence of parvoviruses of carnivores

PubMed Central

Hoelzer, Karin; Parrish, Colin R.

2010-01-01

The emergence of canine parvovirus (CPV) represents a well-documented example highlighting the emergence of a new virus through cross-species transmission. CPV emerged in the mid-1970s as a new pathogen of dogs and has since become endemic in the global dog population. Despite widespread vaccination, CPV has remained a widespread disease of dogs, and new genetic and antigenic variants have arisen and sometimes reached high frequency in certain geographic regions or throughout the world. Here we review our understanding of this emergence event and contrast it to what is known about the emergence of a disease in mink caused by mink enteritis virus (MEV). In addition, we summarize the evolution of CPV over the past 30 years in the global dog population, and describe the epidemiology of contemporary parvovirus infections of dogs and cats. CPV represents a valuable model for understanding disease emergence through cross-species transmission, while MEV provides an interesting comparison. PMID:20152105

Brevibacterium casei as a cause of brain abscess in an immunocompetent patient.

PubMed

Kumar, V Anil; Augustine, Deepthi; Panikar, Dilip; Nandakumar, Aswathy; Dinesh, Kavitha R; Karim, Shamsul; Philip, Rosamma

2011-12-01

Coryneform bacteria belonging to the genus Brevibacterium have emerged as opportunistic pathogens. Of the nine known species of Brevibacterium isolated from human clinical samples, Brevibacterium casei is the most frequently reported species from clinical specimens. We report the first case of B. casei brain abscess in an immunocompetent patient successfully treated by surgery and antimicrobial therapy.

Use of multiple sequencing technologies to produce a high-quality genome of the fungus Pseudogymnoascus destructans, the causative agent of bat White-Nose syndrome

USGS Publications Warehouse

Drees, Kevin P.; Palmer, Jonathan M.; Sebra, Robert; Lorch, Jeffrey M.; Chen, Cynthia; Wu, ChengCang; Bok, Jin Woo; Keller, Nancy F.; Blehert, David; Cuomo, Christina A.; Linder, Daniel L.; Foster, Jeffrey T.

2016-01-01

White-Nose syndrome has recently emerged as one of the most devastating wildlife diseases recorded, causing widespread mortality in numerous bat species throughout eastern North America. Here, we present an improvised reference genome of the fungal pathogen Pseudogymnoascus destructans for use in comparative genomic studies.

An Improved Medium for Growing Staphylococcus aureus Biofilm

DTIC Science & Technology

2012-04-19

implantitis, chronic wound infections , chronic rhinosinusitis, endocarditis , and ocular infections (Archer et al., 2011). In addition, emerging evidence...causes of human bacterial infections , Staphylococcus aureus, a gram positive organism, is a ubiquitous oppor tunistic pathogen that commonly colonizes...resistant to antibiotic therapy. It has been shown that S. aureus biofilms are involved in oste omyelitis; indwelling medical device infections ; and peri

Use of Multiple Sequencing Technologies To Produce a High-Quality Genome of the Fungus Pseudogymnoascus destructans, the Causative Agent of Bat White-Nose Syndrome

PubMed Central

Sebra, Robert; Lorch, Jeffrey M.; Chen, Cynthia; Wu, Cheng-Cang; Bok, Jin Woo; Keller, Nancy P.; Blehert, David S.; Lindner, Daniel L.

2016-01-01

White-nose syndrome has recently emerged as one of the most devastating wildlife diseases recorded, causing widespread mortality in numerous bat species throughout eastern North America. Here, we present an improved reference genome of the fungal pathogen Pseudogymnoascus destructans for use in comparative genomic studies. PMID:27365344

Engineered disease resistance in cotton using RNA-interference to knock down cotton leaf curl kokhran virus-Burewala and cotton leaf curl Multan betasatellite

USDA-ARS?s Scientific Manuscript database

Cotton Leaf Curl virus Disease (CLCuD) has caused enormous losses in cotton (Gossypium hirsutum) production in Pakistan. RNA interference (RNAi) is an emerging technique that could knock out CLCuD by targeting different regions of the pathogen genome that are important for replication, transcription...

Use of multiple sequencing technologies to produce a high-quality genome of the fungus Pseudogymnoascus destructans, the causative agent of bat white-nose syndrome

Treesearch

Kevin P. Drees; Jonathan M. Palmer; Robert Sebra; Jeffrey M. Lorch; Cynthia Chen; Cheng-Cang Wu; Jin Woo Bok; Nancy P. Keller; David S. Blehert; Christina A. Cuomo; Daniel L. Lindner; Jeffrey T. Foster

2016-01-01

White-nose syndrome has recently emerged as one of the most devastating wildlife diseases recorded, causing widespread mortality in numerous bat species throughout eastern North America. Here, we present an improved reference genome of the fungal pathogen Pseudogymnoascus destructans for use in comparative genomic studies.

Animal Movement and Establishment of Vaccinia Virus Cantagalo Strain in Amazon Biome, Brazil

PubMed Central

Quixabeira-Santos, Jociane Cristina; Medaglia, Maria Luiza G.; Pescador, Caroline A.

2011-01-01

To understand the emergence of vaccinia virus Cantagalo strain in the Amazon biome of Brazil, during 2008–2010 we conducted a molecular and epidemiologic survey of poxvirus outbreaks. Data indicate that animal movement was the major cause of virus dissemination within Rondônia State, leading to the establishment and spread of this pathogen. PMID:21470472

Cyprinid herpesvirus 2 infection emerged in cultured gibel carp, Carassius auratus gibelio in China.

PubMed

Xu, Jin; Zeng, Lingbing; Zhang, Hui; Zhou, Yong; Ma, Jie; Fan, Yuding

2013-09-27

An epizootic with severe mortality has emerged in cultured gibel carp, Carassius auratus gibelio, in China since 2009, and caused huge economic loss. The signs and epidemiology background of the disease were investigated. Parasite examination, bacteria and virus isolation were carried out for pathogen isolation. The causative pathogen was obtained and identified as Cyprinid herpesvirus 2 (CyHV-2) by experimental infection, electron microscopy, cell culture, PCR assay and sequence alignment, designated as CyHV-2-JSSY. Experimental infection proved the high virulence of CyHV-2-JSSY to healthy gibel carp. Electron microscopy revealed that the viral nucleocapsid was hexagonal in shape measuring 110-120 nm in diameter with a 170-200 nm envelope. The virus caused significant CPE in Koi-Fin cells at the early passages, but not beyond the fifth passages. Sequence alignment of the partial viral helicase gene (JX566884) showed that it shared 99-100% identity to the published sequences of other CyHV-2 isolates. This study represented the first isolation and identification of CyHV-2 in cultured gibel carp in China and laid a foundation for the further studies of the disease. Copyright © 2013 Elsevier B.V. All rights reserved.

Biological characterization of highly pathogenic avian influenza H5N1 viruses that infected humans in Egypt in 2014-2015.

PubMed

El-Shesheny, Rabeh; Mostafa, Ahmed; Kandeil, Ahmed; Mahmoud, Sara H; Bagato, Ola; Naguib, Amel; Refaey, Samir El; Webby, Richard J; Ali, Mohamed A; Kayali, Ghazi

2017-03-01

Highly pathogenic avian influenza (HPAI) H5N1 influenza viruses emerged as a human pathogen in 1997 with expected potential to undergo sustained human-to-human transmission and pandemic viral spread. HPAI H5N1 is endemic in Egyptian poultry and has caused sporadic human infection. The first outbreak in early 2006 was caused by clade 2.2 viruses that rapidly evolved genetically and antigenically. A sharp increase in the number of human cases was reported in Egypt in the 2014/2015 season. In this study, we analyzed and characterized three isolates of HPAI H5N1 viruses isolated from infected humans in Egypt in 2014/2015. Phylogenetic analysis demonstrated that the nucleotide sequences of eight segments of the three isolates were clustered with those of members of clade 2.2.1.2. We also found that the human isolates from 2014/2015 had a slight, non-significant difference in their affinity for human-like sialic acid receptors. In contrast, they showed significant differences in their replication kinetics in MDCK, MDCK-SIAT, and A549 cells as well as in embryonated chicken eggs. An antiviral bioassay study revealed that all of the isolates were susceptible to amantadine. Therefore, further investigation and monitoring is required to correlate the genetic and/or antigenic changes of the emerging HPAI H5N1 viruses with possible alteration in their characteristics and their potential to become a further threat to public health.

Effect of chipping on emergence of the redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae) and recovery of the laurel wilt pathogen from infested wood chips.

PubMed

Spence, D J; Smith, J A; Ploetz, R; Hulcr, J; Stelinski, L L

2013-10-01

Significant mortality ofredbay trees (Persea borbonia (L.) Spreng.) in the southeastern United States has been caused by Raffaelea lauricola, T.C. Harr., Fraedrich, & Aghayeva (Harrington et al. 2008), a fungal symbiont of the exotic redbay ambrosia beetle, Xyleborus glabratus, Eichhoff (Fraedrich et al. 2008). This pathogen causes laurel wilt, which is an irreversible disease that can kill mature trees within a few weeks in summer. R. lauricola has been shown to be lethal to most native species of Lauraceae and cultivated avocado (Persea americana Mill.) in the southeastern United States. In this study, we examined the survival of X. glabratus and R. lauricola in wood chips made from infested trees by using a standard tree chipper over a 10-wk period. After 2 wk, 14 X. glabratus were recovered from wood chips, whereas 339 X. glabratus emerged from nonchipped bolts. R. lauricola was not found 2 d postchipping from wood chips, indicating that the pathogen is not likely to survive for long inside wood chips. In contrast, R. lauricola persisted in dead, standing redbay trees for 14 mo. With large volumes of wood, the potential for infested logs to be moved between states or across U.S. borders is significant. Results demonstrated that chipping wood from laurel wilt-killed trees can significantly reduce the number of X. glabratus and limit the persistence of R. lauricola, which is important for sanitation strategies aimed at limiting the spread of this disease.

Update on Tick-Borne Rickettsioses around the World: a Geographic Approach

PubMed Central

Paddock, Christopher D.; Socolovschi, Cristina; Labruna, Marcelo B.; Mediannikov, Oleg; Kernif, Tahar; Abdad, Mohammad Yazid; Stenos, John; Bitam, Idir; Fournier, Pierre-Edouard; Raoult, Didier

2013-01-01

SUMMARY Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These zoonoses are among the oldest known vector-borne diseases. However, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. Several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections, and novel Rickettsia species of undetermined pathogenicity continue to be detected in or isolated from ticks around the world. This remarkable expansion of information has been driven largely by the use of molecular techniques that have facilitated the identification of novel and previously recognized rickettsiae in ticks. New approaches, such as swabbing of eschars to obtain material to be tested by PCR, have emerged in recent years and have played a role in describing emerging tick-borne rickettsioses. Here, we present the current knowledge on tick-borne rickettsiae and rickettsioses using a geographic approach toward the epidemiology of these diseases. PMID:24092850

Early detection of emerging zoonotic diseases with animal morbidity and mortality monitoring.

PubMed

Bisson, Isabelle-Anne; Ssebide, Benard J; Marra, Peter P

2015-03-01

Diseases transmitted between animals and people have made up more than 50% of emerging infectious diseases in humans over the last 60 years and have continued to arise in recent months. Yet, public health and animal disease surveillance programs continue to operate independently. Here, we assessed whether recent emerging zoonotic pathogens (n = 143) are known to cause morbidity or mortality in their animal host and if so, whether they were first detected with an animal morbidity/mortality event. We show that although sick or dead animals are often associated with these pathogens (52%), only 9% were first detected from an animal morbidity or mortality event prior to or concurrent with signs of illness in humans. We propose that an animal morbidity and mortality reporting program will improve detection and should be an essential component of early warning systems for zoonotic diseases. With the use of widespread low-cost technology, such a program could engage both the public and professionals and be easily tested and further incorporated as part of surveillance efforts by public health officials.

The emergence of Vibrio pathogens in Europe: ecology, evolution, and pathogenesis (Paris, 11–12th March 2015)

PubMed Central

Roux, Frédérique Le; Wegner, K. Mathias; Baker-Austin, Craig; Vezzulli, Luigi; Osorio, Carlos R.; Amaro, Carmen; Ritchie, Jennifer M.; Defoirdt, Tom; Destoumieux-Garzón, Delphine; Blokesch, Melanie; Mazel, Didier; Jacq, Annick; Cava, Felipe; Gram, Lone; Wendling, Carolin C.; Strauch, Eckhard; Kirschner, Alexander; Huehn, Stephan

2015-01-01

Global change has caused a worldwide increase in reports of Vibrio-associated diseases with ecosystem-wide impacts on humans and marine animals. In Europe, higher prevalence of human infections followed regional climatic trends with outbreaks occurring during episodes of unusually warm weather. Similar patterns were also observed in Vibrio-associated diseases affecting marine organisms such as fish, bivalves and corals. Basic knowledge is still lacking on the ecology and evolutionary biology of these bacteria as well as on their virulence mechanisms. Current limitations in experimental systems to study infection and the lack of diagnostic tools still prevent a better understanding of Vibrio emergence. A major challenge is to foster cooperation between fundamental and applied research in order to investigate the consequences of pathogen emergence in natural Vibrio populations and answer federative questions that meet societal needs. Here we report the proceedings of the first European workshop dedicated to these specific goals of the Vibrio research community by connecting current knowledge to societal issues related to ocean health and food security. PMID:26322036

Mechanisms of innate immune evasion in re-emerging RNA viruses.

PubMed

Ma, Daphne Y; Suthar, Mehul S

2015-06-01

Recent outbreaks of Ebola, West Nile, Chikungunya, Middle Eastern Respiratory and other emerging/re-emerging RNA viruses continue to highlight the need to further understand the virus-host interactions that govern disease severity and infection outcome. As part of the early host antiviral defense, the innate immune system mediates pathogen recognition and initiation of potent antiviral programs that serve to limit virus replication, limit virus spread and activate adaptive immune responses. Concordantly, viral pathogens have evolved several strategies to counteract pathogen recognition and cell-intrinsic antiviral responses. In this review, we highlight the major mechanisms of innate immune evasion by emerging and re-emerging RNA viruses, focusing on pathogens that pose significant risk to public health. Copyright © 2015 Elsevier B.V. All rights reserved.

Streptococcus suis: a re-emerging pathogen associated with occupational exposure to pigs or pork products. Part II - Pathogenesis.

PubMed

Dutkiewicz, Jacek; Zając, Violetta; Sroka, Jacek; Wasiński, Bernard; Cisak, Ewa; Sawczyn, Anna; Kloc, Anna; Wójcik-Fatla, Angelina

2018-03-14

Streptococcus suis is a re-emerging zoonotic pathogen that may cause severe disease, mostly meningitis, in pigs and in humans having occupational contact with pigs and pork, such as farmers, slaughterhose workers and butchers. The first stage of the pathogenic process, similar in pigs and humans, is adherence to and colonisation of mucosal and/or epithelial surface(s) of the host. The second stage is invasion into deeper tissue and extracellular translocation of bacterium in the bloodstream, either free in circulation or attached to the surface of monocytes. If S. suis present in blood fails to cause fatal septicaemia, it is able to progress into the third stage comprising penetration into host's organs, mostly by crossing the blood-brain barrier and/or blood-cerebrospinal fluid barrier to gain access to the central nervous system (CNS) and cause meningitis. The fourth stage is inflammation that plays a key role in the pathogen esis of both systemic and CNS infections caused by S. suis. The pathogen may induce the overproduction of pro-inflammatory cytokines that cause septic shock and/or the recruitment and activation of different leukocyte populations, causing acute inflammation of the CNS. Streptococcus suis can also evoke - through activation of microglial cells, astrocytes and possibly other cell types - a fulminant inflammatory reaction of the brain which leads to intracranial complications, including brain oedema, increased intracranial pressure, cerebrovascular insults, and deafness, as a result of cochlear sepsis. In all stages of the pathogenic process, S. suis interacts with many types of immunocompetent host's cells, such as polymorphonuclear leukocytes, mononuclear macrophages, lymphocytes, dendritic cells and microglia, using a range of versatile virulence factors for evasion of the innate and adaptive immune defence of the host, and for overcoming environmental stress. It is estimated that S. suis produces more than 100 different virulence factors that could be classified into 4 groups: surface components or secreted elements, enzymes, transcription factors or regulatory systems and transporter factors or secretion systems. A major virulence factor is capsular polysaccharide (CPS) that protects bacteria from phagocytosis. However, it hampers adhesion to and invasion of host's cells, release of inflammatory cytokines and formation of the resistant biofilm which, in many cases, is vital for the persistence of bacteria. It has been demonstrated that the arising by mutation unencapsulated S. suis clones, which are more successful in penetration to and propagation within the host's cells, may coexist in the organism of a single host together with those that are encapsulated. Both 'complementary' clones assist each other in the successful colonization of host's tissues and persistence therein. S. suis has an open pan-genome characterized by a frequent gene transfer and a large diversity. Of the genetic determinants of S. suis pathogenicity, the most important are pathogenicity islands (PAI), in particular, a novel DNA segment of 89 kb length with evident pathogenic traits that has been designated as 89K PAI. It has been estimated that more than one-third of the S. suis virulence factors is associated with this PAI. It has been proved that the virulent S. suis strains possess smaller genomes, compared to avirulent ones, but more genes associated with virulence. Overall, the evolution of the species most probably aims towards increased pathogenicity, and hence the most significant task of the current research is an elaboration of a vaccine, efficient both for humans and pigs.

The Z Proteins of Pathogenic but Not Nonpathogenic Arenaviruses Inhibit RIG-i-Like Receptor-Dependent Interferon Production

PubMed Central

Xing, Junji; Ly, Hinh

2014-01-01

ABSTRACT Arenavirus pathogens cause a wide spectrum of diseases in humans ranging from central nervous system disease to lethal hemorrhagic fevers with few treatment options. The reason why some arenaviruses can cause severe human diseases while others cannot is unknown. We find that the Z proteins of all known pathogenic arenaviruses, lymphocytic choriomeningitis virus (LCMV) and Lassa, Junin, Machupo, Sabia, Guanarito, Chapare, Dandenong, and Lujo viruses, can inhibit retinoic acid-inducible gene 1 (RIG-i) and Melanoma Differentiation-Associated protein 5 (MDA5), in sharp contrast to those of 14 other nonpathogenic arenaviruses. Inhibition of the RIG-i-like receptors (RLRs) by pathogenic Z proteins is mediated by the protein-protein interactions of Z and RLRs, which lead to the disruption of the interactions between RLRs and mitochondrial antiviral signaling (MAVS). The Z-RLR interactive interfaces are located within the N-terminal domain (NTD) of the Z protein and the N-terminal CARD domains of RLRs. Swapping of the LCMV Z NTD into the nonpathogenic Pichinde virus (PICV) genome does not affect virus growth in Vero cells but significantly inhibits the type I interferon (IFN) responses and increases viral replication in human primary macrophages. In summary, our results show for the first time an innate immune-system-suppressive mechanism shared by the diverse pathogenic arenaviruses and thus shed important light on the pathogenic mechanism of human arenavirus pathogens. IMPORTANCE We show that all known human-pathogenic arenaviruses share an innate immune suppression mechanism that is based on viral Z protein-mediated RLR inhibition. Our report offers important insights into the potential mechanism of arenavirus pathogenesis, provides a convenient way to evaluate the pathogenic potential of known and/or emerging arenaviruses, and reveals a novel target for the development of broad-spectrum therapies to treat this group of diverse pathogens. More broadly, our report provides a better understanding of the mechanisms of viral immune suppression and host-pathogen interactions. PMID:25552708

Low-pathogenic influenza A viruses in North American diving ducks contribute to the emergence of a novel highly pathogenic influenza A(H7N8) virus

USGS Publications Warehouse

Xu, Yifei; Ramey, Andrew M.; Bowman, Andrew S; DeLiberto, Thomas J.; Killian, Mary Lea; Krauss, Scott; Nolting, Jacqueline M.; Torchetti, Mia Kim; Reeves, Andrew B.; Webby, Richard J.; Stallknecht, David E.; Wan, Xiu-Feng

2017-01-01

Introductions of low-pathogenic avian influenza (LPAI) viruses of subtypes H5 and H7 into poultry from wild birds have the potential to mutate to highly pathogenic avian influenza (HPAI) viruses, but such viruses' origins are often unclear. In January 2016, a novel H7N8 HPAI virus caused an outbreak in turkeys in Indiana, USA. To determine the virus's origin, we sequenced the genomes of 441 wild-bird origin influenza A viruses (IAVs) from North America and subjected them to evolutionary analyses. The results showed that the H7N8 LPAI virus most likely circulated among diving ducks in the Mississippi flyway during autumn 2015 and was subsequently introduced to Indiana turkeys, in which it evolved high pathogenicity. Preceding the outbreak, an isolate with six gene segments (PB2, PB1, PA, HA, NA, and NS) sharing >99% sequence identity with those of H7N8 turkey isolates was recovered from a diving duck sampled in Kentucky, USA. H4N8 IAVs from other diving ducks possessed five H7N8-like gene segments (PB2, PB1, NA, MP, and NS; >98% sequence identity). Our findings suggest that viral gene constellations circulating among diving ducks can contribute to the emergence of IAVs that affect poultry. Therefore, diving ducks may serve an important and understudied role in the maintenance, diversification, and transmission of IAVs in the wild-bird reservoir.

Both Genome Segments Contribute to the Pathogenicity of Very Virulent Infectious Bursal Disease Virus

PubMed Central

Escaffre, Olivier; Le Nouën, Cyril; Amelot, Michel; Ambroggio, Xavier; Ogden, Kristen M.; Guionie, Olivier; Toquin, Didier; Müller, Hermann; Islam, Mohammed R.

2013-01-01

Infectious bursal disease virus (IBDV) causes an economically significant disease of chickens worldwide. Very virulent IBDV (vvIBDV) strains have emerged and induce as much as 60% mortality. The molecular basis for vvIBDV pathogenicity is not understood, and the relative contributions of the two genome segments, A and B, to this phenomenon are not known. Isolate 94432 has been shown previously to be genetically related to vvIBDVs but exhibits atypical antigenicity and does not cause mortality. Here the full-length genome of 94432 was determined, and a reverse genetics system was established. The molecular clone was rescued and exhibited the same antigenicity and reduced pathogenicity as isolate 94432. Genetically modified viruses derived from 94432, whose vvIBDV consensus nucleotide sequence was restored in segment A and/or B, were produced, and their pathogenicity was assessed in specific-pathogen-free chickens. We found that a valine (position 321) that modifies the most exposed part of the capsid protein VP2 critically modified the antigenicity and partially reduced the pathogenicity of 94432. However, a threonine (position 276) located in the finger domain of the virus polymerase (VP1) contributed even more significantly to attenuation. This threonine is partially exposed in a hydrophobic groove on the VP1 surface, suggesting possible interactions between VP1 and another, as yet unidentified molecule at this amino acid position. The restored vvIBDV-like pathogenicity was associated with increased replication and lesions in the thymus and spleen. These results demonstrate that both genome segments influence vvIBDV pathogenicity and may provide new targets for the attenuation of vvIBDVs. PMID:23269788

Genome sequence of E. coli O104:H4 leads to rapid development of a targeted antimicrobial agent against this emerging pathogen.

USDA-ARS?s Scientific Manuscript database

A recent widespread outbreak of Escherichia coli O104:H4 in Germany demonstrates the dynamic nature of emerging and re-emerging food-borne pathogens, particularly STECs and related pathogenic E. coli. Rapid genomic sequencing and public availability of these data from the German outbreak strain allo...

Evolution and population genetics of exotic and reemerging pathogens: traditional and novel tools and approaches

Treesearch

N.J. Grünwald; E.M. Goss

2011-01-01

Given human population growth and accelerated global trade, the rate of emergence of exotic plant pathogens is bound to increase. Understanding the processes that lead to the emergence of new pathogens can help manage emerging epidemics. Novel tools for analyzing population genetic variation can be used to infer the evolutionary history of populations or species,...

A case of infective endocarditis along with a ruptured valve caused by Streptococcus agalactiae in an immunocompetent man.

PubMed

Suzuki, Kiyozumi; Hirai, Yuji; Morita, Fujiko; Uehara, Yuki; Oshima, Hiroko; Mitsuhashi, Kazunori; Amano, Atsushi; Naito, Toshio

2016-01-01

Streptococcus agalactiae ( S. agalactiae ) is a major cause of invasive disease in neonates and pregnant women, but has also recently been observed among non-pregnant adults, especially elderly persons or persons with underlying chronic disease. S. agalactiae is also a rare cause of infective endocarditis, and most cases require early surgery. We report the case of a 43-year-old previously healthy man who experienced rapid progressive culture-negative infective endocarditis with aortic valve vegetation and severe aortic regurgitation, which was complicated by lumbar spondylodiscitis. Emergency aortic valve replacement was performed on the day of his admission, which revealed a congenital bicuspid aortic valve was ruptured by the vegetation. The resected aortic valve specimen was submitted for 16S ribosomal RNA gene sequencing, which revealed that the pathogen was S. agalactiae . Therefore, S. agalactiae should be considered a potentially causative pathogen in cases of rapid progressive infective endocarditis, even if it occurs in a non-pregnant immunocompetent adult.

Lethality of First Contact Dysentery Epidemics on Pacific Islands

PubMed Central

Shanks, G. Dennis

2016-01-01

Infectious diseases depopulated many isolated Pacific islands when they were first exposed to global pathogen circulation from the 18th century. Although the mortality was great, the lack of medical observers makes determination of what happened during these historical epidemics largely speculative. Bacillary dysentery caused by Shigella is the most likely infection causing some of the most lethal island epidemics. The fragmentary historical record is reviewed to gain insight into the possible causes of the extreme lethality that was observed during first-contact epidemics in the Pacific. Immune aspects of the early dysentery epidemics and postmeasles infection resulting in subacute inflammatory enteric disease suggest that epidemiologic isolation was the major lethality risk factor on Pacific islands in the 19th century. Other possible risk factors include human leukocyte antigen homogeneity from a founder effect and pathogen-induced derangement of immune tolerance to gut flora. If this analysis is correct, then Pacific islands are currently at no greater risk of emerging disease epidemics than other developing countries despite their dark history. PMID:27185765

It shouldn't happen to a dog … or a veterinarian: clinical paradigms for canine vector-borne diseases.

PubMed

Irwin, Peter J

2014-02-01

Canine vector-borne diseases (CVBDs) comprise a diverse group of viral, bacterial, protozoal, and helminth pathogens, transmitted predominantly by ticks and fleas, and cause significant health problems for dogs worldwide. Growing numbers of reports indicate that CVBDs are emerging in regions where they previously did not exist and this, combined with pathogens that are inherently difficult to detect, is providing companion animal veterinarians with some significant diagnostic challenges. This review discusses six paradigms concerning the diagnosis, treatment, prevention, and zoonotic implications of CVBDs from a veterinary clinical perspective. Copyright © 2013 Elsevier Ltd. All rights reserved.

Virulence determinants of pandemic influenza viruses

PubMed Central

Tscherne, Donna M.; García-Sastre, Adolfo

2011-01-01

Influenza A viruses cause recurrent, seasonal epidemics and occasional global pandemics with devastating levels of morbidity and mortality. The ability of influenza A viruses to adapt to various hosts and undergo reassortment events ensures constant generation of new strains with unpredictable degrees of pathogenicity, transmissibility, and pandemic potential. Currently, the combination of factors that drives the emergence of pandemic influenza is unclear, making it impossible to foresee the details of a future outbreak. Identification and characterization of influenza A virus virulence determinants may provide insight into genotypic signatures of pathogenicity as well as a more thorough understanding of the factors that give rise to pandemics. PMID:21206092

Potential for spread of the white-nose fungus (Pseudogymnoascus destructans) in the Americas: use of Maxent and NicheA to assure strict model transference.

PubMed

Escobar, Luis E; Lira-Noriega, Andrés; Medina-Vogel, Gonzalo; Townsend Peterson, A

2014-11-01

Emerging infectious diseases can present serious threats to wildlife, even to the point of causing extinction. Whitenose fungus (Pseudogymnoascus destructans) is causing an epizootic in bats that is expanding rapidly, both geographically and taxonomically. Little is known of the ecology and distributional potential of this intercontinental pathogen. We address this gap via ecological niche models that characterise coarse resolution niche differences between fungus populations on different continents, identifying areas potentially vulnerable to infection in South America. Here we explore a novel approach to identifying areas of potential distribution across novel geographic regions that avoids perilious extrapolation into novel environments. European and North American fungus populations show differential use of environmental space, but rather than niche differentiation, we find that changes are best attributed to climatic differences between the two continents. Suitable areas for spread of the pathogen were identified across southern South America; however caution should be taken to avoid underestimating the potential for spread of this pathogen in South America.

Low-Pathogenic Influenza A Viruses in North American Diving Ducks Contribute to the Emergence of a Novel Highly Pathogenic Influenza A(H7N8) Virus.

PubMed

Xu, Yifei; Ramey, Andrew M; Bowman, Andrew S; DeLiberto, Thomas J; Killian, Mary L; Krauss, Scott; Nolting, Jacqueline M; Torchetti, Mia Kim; Reeves, Andrew B; Webby, Richard J; Stallknecht, David E; Wan, Xiu-Feng

2017-05-01

Introductions of low-pathogenic avian influenza (LPAI) viruses of subtypes H5 and H7 into poultry from wild birds have the potential to mutate to highly pathogenic avian influenza (HPAI) viruses, but such viruses' origins are often unclear. In January 2016, a novel H7N8 HPAI virus caused an outbreak in turkeys in Indiana, USA. To determine the virus's origin, we sequenced the genomes of 441 wild-bird origin influenza A viruses (IAVs) from North America and subjected them to evolutionary analyses. The results showed that the H7N8 LPAI virus most likely circulated among diving ducks in the Mississippi flyway during autumn 2015 and was subsequently introduced to Indiana turkeys, in which it evolved high pathogenicity. Preceding the outbreak, an isolate with six gene segments (PB2, PB1, PA, HA, NA, and NS) sharing >99% sequence identity with those of H7N8 turkey isolates was recovered from a diving duck sampled in Kentucky, USA. H4N8 IAVs from other diving ducks possessed five H7N8-like gene segments (PB2, PB1, NA, MP, and NS; >98% sequence identity). Our findings suggest that viral gene constellations circulating among diving ducks can contribute to the emergence of IAVs that affect poultry. Therefore, diving ducks may serve an important and understudied role in the maintenance, diversification, and transmission of IAVs in the wild-bird reservoir. IMPORTANCE In January 2016, a novel H7N8 HPAI virus caused a disease outbreak in turkeys in Indiana, USA. To determine the origin of this virus, we sequenced and analyzed 441 wild-bird origin influenza virus strains isolated from wild birds inhabiting North America. We found that the H7N8 LPAI virus most likely circulated among diving ducks in the Mississippi flyway during autumn 2015 and was subsequently introduced to Indiana turkeys, in which it evolved high pathogenicity. Our results suggest that viral gene constellations circulating among diving ducks can contribute to the emergence of IAVs that affect poultry. Therefore, diving ducks may play an important and understudied role in the maintenance, diversification, and transmission of IAVs in the wild-bird reservoir. Our study also highlights the importance of a coordinated, systematic, and collaborative surveillance for IAVs in both poultry and wild-bird populations. Copyright © 2017 American Society for Microbiology.

Low-Pathogenic Influenza A Viruses in North American Diving Ducks Contribute to the Emergence of a Novel Highly Pathogenic Influenza A(H7N8) Virus

PubMed Central

Xu, Yifei; Bowman, Andrew S.; DeLiberto, Thomas J.; Killian, Mary L.; Krauss, Scott; Nolting, Jacqueline M.; Torchetti, Mia Kim; Reeves, Andrew B.; Webby, Richard J.; Stallknecht, David E.

2017-01-01

ABSTRACT Introductions of low-pathogenic avian influenza (LPAI) viruses of subtypes H5 and H7 into poultry from wild birds have the potential to mutate to highly pathogenic avian influenza (HPAI) viruses, but such viruses' origins are often unclear. In January 2016, a novel H7N8 HPAI virus caused an outbreak in turkeys in Indiana, USA. To determine the virus's origin, we sequenced the genomes of 441 wild-bird origin influenza A viruses (IAVs) from North America and subjected them to evolutionary analyses. The results showed that the H7N8 LPAI virus most likely circulated among diving ducks in the Mississippi flyway during autumn 2015 and was subsequently introduced to Indiana turkeys, in which it evolved high pathogenicity. Preceding the outbreak, an isolate with six gene segments (PB2, PB1, PA, HA, NA, and NS) sharing >99% sequence identity with those of H7N8 turkey isolates was recovered from a diving duck sampled in Kentucky, USA. H4N8 IAVs from other diving ducks possessed five H7N8-like gene segments (PB2, PB1, NA, MP, and NS; >98% sequence identity). Our findings suggest that viral gene constellations circulating among diving ducks can contribute to the emergence of IAVs that affect poultry. Therefore, diving ducks may serve an important and understudied role in the maintenance, diversification, and transmission of IAVs in the wild-bird reservoir. IMPORTANCE In January 2016, a novel H7N8 HPAI virus caused a disease outbreak in turkeys in Indiana, USA. To determine the origin of this virus, we sequenced and analyzed 441 wild-bird origin influenza virus strains isolated from wild birds inhabiting North America. We found that the H7N8 LPAI virus most likely circulated among diving ducks in the Mississippi flyway during autumn 2015 and was subsequently introduced to Indiana turkeys, in which it evolved high pathogenicity. Our results suggest that viral gene constellations circulating among diving ducks can contribute to the emergence of IAVs that affect poultry. Therefore, diving ducks may play an important and understudied role in the maintenance, diversification, and transmission of IAVs in the wild-bird reservoir. Our study also highlights the importance of a coordinated, systematic, and collaborative surveillance for IAVs in both poultry and wild-bird populations. PMID:28202755

Streptococcus suis - The "Two Faces" of a Pathobiont in the Porcine Respiratory Tract.

PubMed

Vötsch, Désirée; Willenborg, Maren; Weldearegay, Yenehiwot B; Valentin-Weigand, Peter

2018-01-01

Streptococcus (S.) suis is a frequent early colonizer of the upper respiratory tract of pigs. In fact, it is difficult to find S. suis -free animals under natural conditions, showing the successful adaptation of this pathogen to its porcine reservoir host. On the other hand, S. suis can cause life-threatening diseases and represents the most important bacterial cause of meningitis in pigs worldwide. Notably, S. suis can also cause zoonotic infections, such as meningitis, septicemia, endocarditis, and other diseases in humans. In Asia, it is classified as an emerging zoonotic pathogen and currently considered as one of the most important causes of bacterial meningitis in adults. The "two faces" of S. suis , one of a colonizing microbe and the other of a highly invasive pathogen, have raised many questions concerning the interpretation of diagnostic detection and the definition of virulence. Thus, one major research challenge is the identification of virulence-markers which allow differentiation of commensal and virulent strains. This is complicated by the high phenotypic and genotypic diversity of S. suis , as reflected by the occurrence of (at least) 33 capsular serotypes. In this review, we present current knowledge in the context of S. suis as a highly diverse pathobiont in the porcine respiratory tract that can exploit disrupted host homeostasis to flourish and promote inflammatory processes and invasive diseases in pigs and humans.

Streptococcus suis – The “Two Faces” of a Pathobiont in the Porcine Respiratory Tract

PubMed Central

Vötsch, Désirée; Willenborg, Maren; Weldearegay, Yenehiwot B.; Valentin-Weigand, Peter

2018-01-01

Streptococcus (S.) suis is a frequent early colonizer of the upper respiratory tract of pigs. In fact, it is difficult to find S. suis-free animals under natural conditions, showing the successful adaptation of this pathogen to its porcine reservoir host. On the other hand, S. suis can cause life-threatening diseases and represents the most important bacterial cause of meningitis in pigs worldwide. Notably, S. suis can also cause zoonotic infections, such as meningitis, septicemia, endocarditis, and other diseases in humans. In Asia, it is classified as an emerging zoonotic pathogen and currently considered as one of the most important causes of bacterial meningitis in adults. The “two faces” of S. suis, one of a colonizing microbe and the other of a highly invasive pathogen, have raised many questions concerning the interpretation of diagnostic detection and the definition of virulence. Thus, one major research challenge is the identification of virulence-markers which allow differentiation of commensal and virulent strains. This is complicated by the high phenotypic and genotypic diversity of S. suis, as reflected by the occurrence of (at least) 33 capsular serotypes. In this review, we present current knowledge in the context of S. suis as a highly diverse pathobiont in the porcine respiratory tract that can exploit disrupted host homeostasis to flourish and promote inflammatory processes and invasive diseases in pigs and humans. PMID:29599763

Relatively low prevalence of Babesia microti and Anaplasma phagocytophilum in Ixodes scapularis ticks collected in the Lehigh Valley region of eastern Pennsylvania.

PubMed

Edwards, Marten J; Barbalato, Laura A; Makkapati, Amulya; Pham, Katerina D; Bugbee, Louise M

2015-09-01

Several human pathogens are transmitted by the blacklegged tick, Ixodes scapularis. These include the spirochetes that cause Lyme disease (Borrelia burgdorferi) which is endemic to the Lehigh Valley region of eastern Pennsylvania. Emerging and currently rare tick-borne diseases have been of increasing concern in this region, including tick-borne relapsing fever (caused by Borrelia miyamotoi), human granulocytic anaplasmosis (caused by Anaplasma phagocytophilum), and human babesiosis (caused by Babesia microti). Real-time PCR assays and in some instances, conventional PCR followed by DNA sequencing, were used to screen 423 DNA samples that were prepared from questing adult and nymph stage I. scapularis ticks for infection with four tick-borne human pathogens. B. burgdorferi was detected in 23.2% of the sampled ticks, while B. miyamotoi, B. microti and a human variant of A. phagocytophilum were detected in less than 0.5% of the ticks. Our results are consistent with those expected in a region where Lyme disease is prevalent and human cases of tick-borne relapsing fever, babesiosis and human granulocytic anaplasmosis are not currently widespread. It is expected that this study will serve as a baseline for future studies of tick-borne pathogens in an area that is in close proximity to regions of high endemicity for Lyme disease, human granulocytic anaplasmosis and human babesiosis. Copyright © 2015 Elsevier GmbH. All rights reserved.

Emerging foodborne pathogens

USDA-ARS?s Scientific Manuscript database

The emergence of new foodborne pathogens is due to a number of factors. An important factor is the globalization of the food supply with the possibility of the introduction of foodborne pathogens from other countries. Animal husbandry, food production, food processing, and food distribution system...

[Emergent diseases: old and new diseases. Etiological and climatic aspects. Socioeconomic and cultural influences].

PubMed

Cabello, F; Springer, A D

1997-01-01

During recent years the world has experienced the reemergence of old communicable diseases and the emergence of new ones caused by novel pathogens such as the HIV virus and Borrelia burgdorferi. The problem consists mostly in the reemergence of old diseases but specially in industrialized countries new pathogens have also been described. Although the emergence of these infections in rare instances is due to genetic changes of pathogens to more virulent forms, most commonly they are due to changes in the environment and the host. Rapidly deteriorating living standards, disintegration of sanitation and public health infrastructure, cultural changes, migration and variations in behavior are some of the factors involved in the worldwide increase of infectious diseases. The degradation of natural habitats including forests and marine niches accompanied by climatic changes, are also playing an increasing role in the detrimental evolution of these diseases. The global emergence of these diseases calls into question the doctrine of epidemiological transition and directs us to scrutinize the paradigm that bases the prevention of these diseases solely on vaccination. The current situation also highlights the limitations of classical epidemiology in dealing with unexpected problems, and strongly suggests that this discipline should incorporate into its analysis findings from other fields, including ecological, climatological, and economical information. As most of the negative social and economical developments that impinge on the detrimental evolution of these diseases are increasing world-wide, it can be predicted that the problems posed by these infections will continue and perhaps worsen in the near future.

Emerging Tick-borne Rickettsia and Ehrlichia at Joint Base Langley-Eustis, Fort Eustis, Virginia.

PubMed

Miller, Melissa K; Jiang, Ju; Truong, Melissa; Yarina, Tamasin; Evans, Holly; Christensen, Timothy P; Richards, Allen L

2016-01-01

Four species of ticks known to parasitize humans (Amblyomma americanum (lone star tick), Dermacentor variabilis (American dog tick), Amblyomma maculatum (Gulf Coast tick), and Ixodes scapularis (black-legged tick)) were collected at Joint Base Langley-Eustis, Fort Eustis, Virginia during 2009. These ticks were tested individually (adults and nymphs) and in pools of 15 (larvae) for pathogens of public health importance within the genera: Rickettsia, Borrelia, and Ehrlichia, by quantitative real-time polymerase chain reaction (qPCR) assays and, where appropriate, multilocus sequence typing (MLST). Of the 340 A americanum ticks tested, a minimum of 65 (19%), 4 (1%), 4 (1%), and one (<1%) were positive for Rickettsia amblyommii, B lonestari, E ewingii and E chaffeensis, respectively. One of 2 (50%) A maculatum ticks collected was found to be positive for R parkeri by MLST and qPCR analyses. All 33 D variabilis ticks were negative for evidence of rickettsial infections. Likewise, no pathogenic organisms were detected from the single Ixodes scapularis tick collected. Pathogenic rickettsiae and ehrlichiae are likely emerging and cause under-recognized diseases, which threaten people who live, work, train, or otherwise engage in outdoor activities at, or in the vicinity of, Fort Eustis, Virginia.

Properties of Gluten Intolerance: Gluten Structure, Evolution, Pathogenicity and Detoxification Capabilities.

PubMed

Balakireva, Anastasia V; Zamyatnin, Andrey A

2016-10-18

Theterm gluten intolerance may refer to three types of human disorders: autoimmune celiac disease (CD), allergy to wheat and non-celiac gluten sensitivity (NCGS). Gluten is a mixture of prolamin proteins present mostly in wheat, but also in barley, rye and oat. Gluten can be subdivided into three major groups: S-rich, S-poor and high molecular weight proteins. Prolamins within the groups possess similar structures and properties. All gluten proteins are evolutionarily connected and share the same ancestral origin. Gluten proteins are highly resistant to hydrolysis mediated by proteases of the human gastrointestinal tract. It results in emergence of pathogenic peptides, which cause CD and allergy in genetically predisposed people. There is a hierarchy of peptide toxicity and peptide recognition by T cells. Nowadays, there are several ways to detoxify gluten peptides: the most common is gluten-free diet (GFD), which has proved its effectiveness; prevention programs, enzymatic therapy, correction of gluten pathogenicity pathways and genetically modified grains with reduced immunotoxicity. A deep understanding of gluten intolerance underlying mechanisms and detailed knowledge of gluten properties may lead to the emergence of novel effective approaches for treatment of gluten-related disorders.

Properties of Gluten Intolerance: Gluten Structure, Evolution, Pathogenicity and Detoxification Capabilities

PubMed Central

Balakireva, Anastasia V.; Zamyatnin, Andrey A.

2016-01-01

Theterm gluten intolerance may refer to three types of human disorders: autoimmune celiac disease (CD), allergy to wheat and non-celiac gluten sensitivity (NCGS). Gluten is a mixture of prolamin proteins present mostly in wheat, but also in barley, rye and oat. Gluten can be subdivided into three major groups: S-rich, S-poor and high molecular weight proteins. Prolamins within the groups possess similar structures and properties. All gluten proteins are evolutionarily connected and share the same ancestral origin. Gluten proteins are highly resistant to hydrolysis mediated by proteases of the human gastrointestinal tract. It results in emergence of pathogenic peptides, which cause CD and allergy in genetically predisposed people. There is a hierarchy of peptide toxicity and peptide recognition by T cells. Nowadays, there are several ways to detoxify gluten peptides: the most common is gluten-free diet (GFD), which has proved its effectiveness; prevention programs, enzymatic therapy, correction of gluten pathogenicity pathways and genetically modified grains with reduced immunotoxicity. A deep understanding of gluten intolerance underlying mechanisms and detailed knowledge of gluten properties may lead to the emergence of novel effective approaches for treatment of gluten-related disorders. PMID:27763541

Epidemiology of Rhodotorula: An Emerging Pathogen

PubMed Central

Wirth, Fernanda; Goldani, Luciano Z.

2012-01-01

This is an updated paper focusing on the general epidemiological aspects of Rhodotorula in humans, animals, and the environment. Previously considered nonpathogenic, Rhodotorula species have emerged as opportunistic pathogens that have the ability to colonise and infect susceptible patients. Rhodotorula species are ubiquitous saprophytic yeasts that can be recovered from many environmental sources. Several authors describe the isolation of this fungus from different ecosystems, including sites with unfavourable conditions. Compared to R. mucilaginosa, R. glutinis and R. minuta are less frequently isolated from natural environments. Among the few references to the pathogenicity of Rhodotorula spp. in animals, there are several reports of an outbreak of skin infections in chickens and sea animals and lung infections and otitis in sheep and cattle. Most of the cases of infection due to Rhodotorula in humans were fungemia associated with central venous catheter (CVC) use. The most common underlying diseases included solid and haematologic malignancies in patients who were receiving corticosteroids and cytotoxic drugs, the presence of CVC, and the use of broad-spectrum antibiotics. Unlike fungemia, some of the other localised infections caused by Rhodotorula, including meningeal, skin, ocular, peritoneal, and prosthetic joint infections, are not necessarily linked to the use of CVCs or immunosuppression. PMID:23091485

Potential targets for next generation antimicrobial glycoconjugate vaccines

PubMed Central

Micoli, Francesca; Costantino, Paolo; Adamo, Roberto

2018-01-01

Abstract Cell surface carbohydrates have been proven optimal targets for vaccine development. Conjugation of polysaccharides to a carrier protein triggers a T-cell-dependent immune response to the glycan moiety. Licensed glycoconjugate vaccines are produced by chemical conjugation of capsular polysaccharides to prevent meningitis caused by meningococcus, pneumococcus and Haemophilus influenzae type b. However, other classes of carbohydrates (O-antigens, exopolysaccharides, wall/teichoic acids) represent attractive targets for developing vaccines. Recent analysis from WHO/CHO underpins alarming concern toward antibiotic-resistant bacteria, such as the so called ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) and additional pathogens such as Clostridium difficile and Group A Streptococcus. Fungal infections are also becoming increasingly invasive for immunocompromised patients or hospitalized individuals. Other emergencies could derive from bacteria which spread during environmental calamities (Vibrio cholerae) or with potential as bioterrorism weapons (Burkholderia pseudomallei and mallei, Francisella tularensis). Vaccination could aid reducing the use of broad-spectrum antibiotics and provide protection by herd immunity also to individuals who are not vaccinated. This review analyzes structural and functional differences of the polysaccharides exposed on the surface of emerging pathogenic bacteria, combined with medical need and technological feasibility of corresponding glycoconjugate vaccines. PMID:29547971

UroPathogenic Escherichia coli (UPEC) Infections: Virulence Factors, Bladder Responses, Antibiotic, and Non-antibiotic Antimicrobial Strategies

PubMed Central

Terlizzi, Maria E.; Gribaudo, Giorgio; Maffei, Massimo E.

2017-01-01

Urinary tract infections (UTIs) are one of the most common pathological conditions in both community and hospital settings. It has been estimated that about 150 million people worldwide develop UTI each year, with high social costs in terms of hospitalizations and medical expenses. Among the common uropathogens associated to UTIs development, UroPathogenic Escherichia coli (UPEC) is the primary cause. UPEC strains possess a plethora of both structural (as fimbriae, pili, curli, flagella) and secreted (toxins, iron-acquisition systems) virulence factors that contribute to their capacity to cause disease, although the ability to adhere to host epithelial cells in the urinary tract represents the most important determinant of pathogenicity. On the opposite side, the bladder epithelium shows a multifaceted array of host defenses including the urine flow and the secretion of antimicrobial substances, which represent useful tools to counteract bacterial infections. The fascinating and intricate dynamics between these players determine a complex interaction system that needs to be revealed. This review will focus on the most relevant components of UPEC arsenal of pathogenicity together with the major host responses to infection, the current approved treatment and the emergence of resistant UPEC strains, the vaccine strategies, the natural antimicrobial compounds along with innovative anti-adhesive and prophylactic approaches to prevent UTIs. PMID:28861072

Current Trends in Plague Research: From Genomics to Virulence

PubMed Central

Huang, Xiao-Zhe; Nikolich, Mikeljon P.; Lindler, Luther E.

2006-01-01

Yersinia pestis is the causative agent of plague, which diverged from Yersinia pseudotuberculosis within the past 20,000 years.Although these two species share a high degree of homology at the DNA level (>90%), they differ radically in their pathogenicity and transmission. In this review, we briefly outline the known virulence factors that differentiate these two species and emphasize genetic studies that have been conducted comparing Y. pestis and Y. pseudotuberculosis.These comparisons have led to a better understanding of the genetic contributions to the differences in the virulence and pathogenicity between these two organisms and have generated information that can be applied in future diagnostic and vaccine development. Comparison of the genetic differences between Y. pestis and Y. pseudotuberculosis has also lent insight into the emergence of acute pathogens from organisms causing milder diseases. PMID:16988099

Serum antibodies from a subset of horses positive for babesia caballi by competitive enzyme-linked immunosorbent assay demonstrate a protein recognition pattern that is not consistent with infection

USDA-ARS?s Scientific Manuscript database

Tick-borne pathogens that cause persistent infection are of major concern to the livestock industry because of transmission risk from persistently infected animals and the potential economic losses they pose. The recent re-emergence of Theileria equi in the U.S. prompted widespread national surveill...

Use of Multiple Sequencing Technologies To Produce a High-Quality Genome of the Fungus Pseudogymnoascus destructans, the Causative Agent of Bat White-Nose Syndrome.

PubMed

Drees, Kevin P; Palmer, Jonathan M; Sebra, Robert; Lorch, Jeffrey M; Chen, Cynthia; Wu, Cheng-Cang; Bok, Jin Woo; Keller, Nancy P; Blehert, David S; Cuomo, Christina A; Lindner, Daniel L; Foster, Jeffrey T

2016-06-30

White-nose syndrome has recently emerged as one of the most devastating wildlife diseases recorded, causing widespread mortality in numerous bat species throughout eastern North America. Here, we present an improved reference genome of the fungal pathogen Pseudogymnoascus destructans for use in comparative genomic studies. Copyright © 2016 Drees et al.

Cyclic avian mass mortality in the northeastern United States is associated with a novel orthomyxovirus

USGS Publications Warehouse

Allison, Andrew B.; Ballard, Jennifer R.; Tesh, Robert B.; Brown, Justin D.; Ruder, Mark G.; Keel, M. Kevin; Munk, Brandon A.; Mickley, Randall M.; Gibbs, Samantha E.J.; Ellis, Julie C.; Travassos da Rosac, Amelia P.A.; Ip, Hon S.; Shearn-Bochsler, Valerie I.; Rogers, Matthew B.; Gheldin, Elodie; Holmes, Edward C.; Parrish, Colin R.; Dwyer, Chris P.

2015-01-01

Importance The emergence or reemergence of viral pathogens resulting in large-scale outbreaks of disease in humans and/or animals is one of the most important challenges facing biomedicine. For example, understanding how orthomyxoviruses such as novel influenza A virus reassortants and/or mutants emerge to cause epidemic or pandemic disease is at the forefront of current global health concerns. Here we describe the emergence of a novel orthomyxovirus, Wellfleet Bay virus (WFBV), which has been associated with cyclic large-scale bird die-offs in the northeastern United States. This initial characterization study provides a foundation for further research into the evolution, epidemiology, and ecology of newly emerging orthomyxoviruses, such as WFBV, and their potential impacts on animal and/or human health.

Identifying species conservation strategies to reduce disease-associated declines

USGS Publications Warehouse

Gerber, Brian D.; Converse, Sarah J.; Muths, Erin L.; Crockett, Harry J.; Mosher, Brittany A.; Bailey, Larissa L.

2018-01-01

Emerging infectious diseases (EIDs) are a salient threat to many animal taxa, causing local and global extinctions, altering communities and ecosystem function. The EID chytridiomycosis is a prominent driver of amphibian declines, which is caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). To guide conservation policy, we developed a predictive decision-analytic model that combines empirical knowledge of host-pathogen metapopulation dynamics with expert judgment regarding effects of management actions, to select from potential conservation strategies. We apply our approach to a boreal toad (Anaxyrus boreas boreas) and Bd system, identifying optimal strategies that balance tradeoffs in maximizing toad population persistence and landscape-level distribution, while considering costs. The most robust strategy is expected to reduce the decline of toad breeding sites from 53% to 21% over 50 years. Our findings are incorporated into management policy to guide conservation planning. Our online modeling application provides a template for managers of other systems challenged by EIDs.

Elucidation of Bacterial Pneumonia-Causing Pathogens in Patients with Respiratory Viral Infection.

PubMed

Jung, Hwa Sik; Kang, Byung Ju; Ra, Seung Won; Seo, Kwang Won; Jegal, Yangjin; Jun, Jae Bum; Jung, Jiwon; Jeong, Joseph; Jeon, Hee Jeong; Ahn, Jae Sung; Lee, Taehoon; Ahn, Jong Joon

2017-10-01

Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ≥16 years, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia. Copyright©2017. The Korean Academy of Tuberculosis and Respiratory Diseases

Guidance to Registrants: Process for Making Claims Against Emerging Viral Pathogens not on EPA-Registered Disinfectant Labels

EPA Pesticide Factsheets

This guidance proposes to use an organism hierarchy to identify effective products for use with emerging pathogens and to permit registrants to make limited statements against such pathogens. It provides general guidance to interested parties.

Tracing the evolutionary history of the pandemic group A streptococcal M1T1 clone

PubMed Central

Maamary, Peter G.; Ben Zakour, Nouri L.; Cole, Jason N.; Hollands, Andrew; Aziz, Ramy K.; Barnett, Timothy C.; Cork, Amanda J.; Henningham, Anna; Sanderson-Smith, Martina; McArthur, Jason D.; Venturini, Carola; Gillen, Christine M.; Kirk, Joshua K.; Johnson, Dwight R.; Taylor, William L.; Kaplan, Edward L.; Kotb, Malak; Nizet, Victor; Beatson, Scott A.; Walker, Mark J.

2012-01-01

The past 50 years has witnessed the emergence of new viral and bacterial pathogens with global effect on human health. The hyperinvasive group A Streptococcus (GAS) M1T1 clone, first detected in the mid-1980s in the United States, has since disseminated worldwide and remains a major cause of severe invasive human infections. Although much is understood regarding the capacity of this pathogen to cause disease, much less is known of the precise evolutionary events selecting for its emergence. We used high-throughput technologies to sequence a World Health Organization strain collection of serotype M1 GAS and reconstructed its phylogeny based on the analysis of core genome single-nucleotide polymorphisms. We demonstrate that acquisition of a 36-kb genome segment from serotype M12 GAS and the bacteriophage-encoded DNase Sda1 led to increased virulence of the M1T1 precursor and occurred relatively early in the molecular evolutionary history of this strain. The more recent acquisition of the phage-encoded superantigen SpeA is likely to have provided selection advantage for the global dissemination of the M1T1 clone. This study provides an exemplar for the evolution and emergence of virulent clones from microbial populations existing commensally or causing only superficial infection.—Maamary, P. G., Ben Zakour, N. L., Cole, J. N., Hollands, A., Aziz, R. K., Barnett, T. C., Cork, A. J., Henningham, A., Sanderson-Smith, M., McArthur, J. D., Venturini, C., Gillen, C. M., Kirk, J. K., Johnson, D. R., Taylor, W. L., Kaplan, E. L., Kotb, M., Nizet, V., Beatson, S. A., Walker, M. J. Tracing the evolutionary history of the pandemic group A streptococcal M1T1 clone. PMID:22878963

Emerging pathogens in the fish farming industry and sequencing-based pathogen discovery.

PubMed

Tengs, Torstein; Rimstad, Espen

2017-10-01

The use of large scale DNA/RNA sequencing has become an integral part of biomedical research. Reduced sequencing costs and the availability of efficient computational resources has led to a revolution in how problems concerning genomics and transcriptomics are addressed. Sequencing-based pathogen discovery represents one example of how genetic data can now be used in ways that were previously considered infeasible. Emerging pathogens affect both human and animal health due to a multitude of factors, including globalization, a shifting environment and an increasing human population. Fish farming represents a relevant, interesting and challenging system to study emerging pathogens. This review summarizes recent progress in pathogen discovery using sequence data, with particular emphasis on viruses in Atlantic salmon (Salmo salar). Copyright © 2017 Elsevier Ltd. All rights reserved.

T-Cell response profiling to biological threat agents including the SARS coronavirus.

PubMed

Gioia, C; Horejsh, D; Agrati, C; Martini, F; Capobianchi, M R; Ippolito, G; Poccia, F

2005-01-01

The emergence of pathogens such as SARS and the increased threat of bioterrorism has stimulated the development of novel diagnostic assays for differential diagnosis. Rather than focusing on the detection of an individual pathogen component, we have developed a T cell profiling system to monitor responses to the pathogens in an array format. Using a matrix of antigens specific for different pathogens, a specific T cell profile was generated for each individual by monitoring the intracellular production of interferon-gamma by flow cytometry. This assay allows for the testing of multiple proteins or peptides at a single time and provides a quantitative and phenotypic assessment of CD4(+) and CD8(+) responding cells. We present profiling examples for several positive individuals, including those vaccinated with the smallpox and anthrax vaccines. We also show antigen optimization for the SARS-hCoV, as studies revealed that these proteins contain peptides which cross-react with more common coronaviruses, a cause of the common cold. The T cell array is an early and sensitive multiplex measure of active infection, exposure to a pathogen, or effective, recent vaccination.

Significance of Viable but Nonculturable Escherichia coli: Induction, Detection, and Control.

PubMed

Ding, Tian; Suo, Yuanjie; Xiang, Qisen; Zhao, Xihong; Chen, Shiguo; Ye, Xingqian; Liu, Donghong

2017-03-28

Diseases caused by foodborne or waterborne pathogens are emerging. Many pathogens can enter into the viable but nonculturable (VBNC) state, which is a survival strategy when exposed to harsh environmental stresses. Pathogens in the VBNC state have the ability to evade conventional microbiological detection methods, posing a significant and potential health risk. Therefore, controlling VBNC bacteria in food processing and the environment is of great importance. As the typical one of the gram-negatives, Escherichia coli ( E. coli ) is a widespread foodborne and waterborne pathogenic bacterium and is able to enter into a VBNC state in extreme conditions (similar to the other gram-negative bacteria), including inducing factors and resuscitation stimulus. VBNC E. coli has the ability to recover both culturability and pathogenicity, which may bring potential health risk. This review describes the concrete factors (nonthermal treatment, chemical agents, and environmental factors) that induce E. coli into the VBNC state, the condition or stimulus required for resuscitation of VBNC E. coli , and the methods for detecting VBNC E. coli . Furthermore, the mechanism of genes and proteins involved in the VBNC E. coli is also discussed in this review.

Case Study of Airborne Pathogen Dispersion Patterns in Emergency Departments with Different Ventilation and Partition Conditions

PubMed Central

Cheong, Chang Heon; Lee, Seonhye

2018-01-01

The prevention of airborne infections in emergency departments is a very important issue. This study investigated the effects of architectural features on airborne pathogen dispersion in emergency departments by using a CFD (computational fluid dynamics) simulation tool. The study included three architectural features as the major variables: increased ventilation rate, inlet and outlet diffuser positions, and partitions between beds. The most effective method for preventing pathogen dispersion and reducing the pathogen concentration was found to be increasing the ventilation rate. Installing partitions between the beds and changing the ventilation system’s inlet and outlet diffuser positions contributed only minimally to reducing the concentration of airborne pathogens. PMID:29534043

Case Study of Airborne Pathogen Dispersion Patterns in Emergency Departments with Different Ventilation and Partition Conditions.

PubMed

Cheong, Chang Heon; Lee, Seonhye

2018-03-13

The prevention of airborne infections in emergency departments is a very important issue. This study investigated the effects of architectural features on airborne pathogen dispersion in emergency departments by using a CFD (computational fluid dynamics) simulation tool. The study included three architectural features as the major variables: increased ventilation rate, inlet and outlet diffuser positions, and partitions between beds. The most effective method for preventing pathogen dispersion and reducing the pathogen concentration was found to be increasing the ventilation rate. Installing partitions between the beds and changing the ventilation system's inlet and outlet diffuser positions contributed only minimally to reducing the concentration of airborne pathogens.

Epidemiology, antibiotic therapy and outcomes of bacteremia caused by drug-resistant ESKAPE pathogens in cancer patients.

PubMed

Bodro, Marta; Gudiol, Carlota; Garcia-Vidal, Carolina; Tubau, Fe; Contra, Anna; Boix, Lucía; Domingo-Domenech, Eva; Calvo, Mariona; Carratalà, Jordi

2014-03-01

Infection due to the six ESKAPE pathogens has recently been identified as a serious emerging problem. However, there is still a lack of information on bacteremia caused by these organisms in cancer patients. We aimed to assess the epidemiology, antibiotic therapy and outcomes of bacteremia due to drug-resistant ESKAPE pathogens (rESKAPE) in patients with cancer. All episodes of bacteremia prospectively documented in hospitalized adults with cancer from 2006 to 2011 were analyzed. Of 1,148 episodes of bacteremia, 392 (34 %) were caused by ESKAPE pathogens. Fifty-four episodes (4.7 %) were due to rESKAPE strains (vancomycin-resistant Enterococcus faecium 0, methicillin-resistant Staphylococcus aureus (MRSA) 13, extended-spectrum beta-lactamase (ESLB)-producing Klebsiella pneumoniae 7, carbapenem-resistant Acinetobacter baumannii 4, carbapenem- and quinolone-resistant Pseudomonas aeruginosa 18 and derepression chromosomic ß-lactam and ESBL-producing Enterobacter species 12. Risk factors independently associated with rESKAPE bacteremia were comorbidities, prior antibiotic therapy, urinary catheter and urinary tract source. Inappropriate empirical antibiotic therapy was more frequent in patients with rESKAPE bacteremia than in the other cases (55.6 % vs. 21.5 %, p < 0.001). Persistence of bacteremia (25 % vs. 9.7 %), septic metastasis (8 % vs. 4 %) and early case-fatality rate (23 % vs. 11 %) were more frequent in patients with rESKAPE bacteremia than in patients with other etiologies (p < 0.05). Bacteremia due to rESKAPE pathogens in cancer patients occurs mainly among those with comorbidities who have received prior antibiotic therapy and have a urinary tract source. These patients often receive inappropriate empirical antibiotic therapy and have a poor outcome.

Whole genome sequencing revealed host adaptation-focused genomic plasticity of pathogenic Leptospira

PubMed Central

Xu, Yinghua; Zhu, Yongzhang; Wang, Yuezhu; Chang, Yung-Fu; Zhang, Ying; Jiang, Xiugao; Zhuang, Xuran; Zhu, Yongqiang; Zhang, Jinlong; Zeng, Lingbing; Yang, Minjun; Li, Shijun; Wang, Shengyue; Ye, Qiang; Xin, Xiaofang; Zhao, Guoping; Zheng, Huajun; Guo, Xiaokui; Wang, Junzhi

2016-01-01

Leptospirosis, caused by pathogenic Leptospira spp., has recently been recognized as an emerging infectious disease worldwide. Despite its severity and global importance, knowledge about the molecular pathogenesis and virulence evolution of Leptospira spp. remains limited. Here we sequenced and analyzed 102 isolates representing global sources. A high genomic variability were observed among different Leptospira species, which was attributed to massive gene gain and loss events allowing for adaptation to specific niche conditions and changing host environments. Horizontal gene transfer and gene duplication allowed the stepwise acquisition of virulence factors in pathogenic Leptospira evolved from a recent common ancestor. More importantly, the abundant expansion of specific virulence-related protein families, such as metalloproteases-associated paralogs, were exclusively identified in pathogenic species, reflecting the importance of these protein families in the pathogenesis of leptospirosis. Our observations also indicated that positive selection played a crucial role on this bacteria adaptation to hosts. These novel findings may lead to greater understanding of the global diversity and virulence evolution of Leptospira spp. PMID:26833181

Immunity to intestinal pathogens: lessons learned from Salmonella

PubMed Central

McSorley, Stephen J.

2014-01-01

Summary Salmonella are a common source of food or water-borne infection and cause a wide range of clinical disease in human and animal hosts. Salmonella are relatively easy to culture and manipulate in a laboratory setting, and the infection of laboratory animals induces robust innate and adaptive immune responses. Thus, immunologists have frequently turned to Salmonella infection models to expand understanding of immunity to intestinal pathogens. In this review, I summarize current knowledge of innate and adaptive immunity to Salmonella and highlight features of this response that have emerged from recent studies. These include the heterogeneity of the antigen-specific T-cell response to intestinal infection, the prominence of microbial mechanisms to impede T and B-cell responses, and the contribution of non-cognate pathways for elicitation of T-cell effector functions. Together, these different issues challenge an overly simplistic view of host-pathogen interaction during mucosal infection but also allow deeper insight into the real-world dynamic of protective immunity to intestinal pathogens. PMID:24942689

Sexually transmitted infection and the evolution of serial monogamy.

PubMed

McLeod, David V; Day, Troy

2014-12-07

The selective forces shaping mating systems have long been of interest to biologists. One particular selective pressure that has received comparatively little attention is sexually transmitted infections (STIs). While it has been hypothesized that STIs could drive the evolutionary emergence of monogamy, there is little theoretical support. Here we use an evolutionary invasion analysis to determine what aspects of pathogen virulence and transmission are necessary for serial monogamy to evolve in a promiscuous population. We derive a biologically intuitive invasion condition in terms of population-specific quantities. From this condition, we obtain two main results. First, when pathogen virulence causes mortality rather than sterility, monogamy is more likely to evolve. Second, we find that at intermediate pathogen transmission rates, monogamy is the most selectively advantageous, whereas at high- and low-transmission rates, monogamy is generally selected against. As a result, it is possible for a pathogen to be highly virulent, yet for promiscuity to persist. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Drivers for the emergence and re-emergence of vector-borne protozoal and bacterial diseases.

PubMed

Harrus, S; Baneth, G

2005-10-01

In recent years, vector-borne parasitic and bacterial diseases have emerged or re-emerged in many geographical regions causing global health and economic problems that involve humans, livestock, companion animals and wild life. The ecology and epidemiology of vector-borne diseases are affected by the interrelations between three major factors comprising the pathogen, the host (human, animal or vector) and the environment. Important drivers for the emergence and spread of vector-borne parasites include habitat changes, alterations in water storage and irrigation habits, atmospheric and climate changes, immunosuppression by HIV, pollution, development of insecticide and drug resistance, globalization and the significant increase in international trade, tourism and travel. War and civil unrest, and governmental or global management failure are also major contributors to the spread of infectious diseases. The improvement of epidemic understanding and planning together with the development of new diagnostic molecular techniques in the last few decades have allowed researchers to better diagnose and trace pathogens, their origin and routes of infection, and to develop preventive public health and intervention programs. Health care workers, physicians, veterinarians and biosecurity officers should play a key role in future prevention of vector-borne diseases. A coordinated global approach for the prevention of vector-borne diseases should be implemented by international organizations and governmental agencies in collaboration with research institutions.

Emergence of new virulent rabbit hemorrhagic disease virus strains in Saudi Arabia.

PubMed

Ismail, Mahmoud M; Mohamed, Mahmoud H A; El-Sabagh, Ibrahim M; Al-Hammadi, Mohamed A

2017-02-01

Rabbit hemorrhagic disease is an acute fatal highly contagious viral infectious disease that causes high losses among rabbitries. The disease was first reported in China in 1984 and later on in Saudi Arabia in 1996. The aim of this study was to investigate the emergence and pathogenicity of new rabbit hemorrhagic disease virus (RHDV) strains in Saudi Arabia. The pathogenicity was confirmed by inoculation in susceptible rabbits. Three RHDV strains were detected by reverse transcriptase polymerase chain reaction (RT-PCR) using primers targeting VP60 capsid protein gene in infected rabbitries during 2012 and 2013. These strains clustered into two genetically distinct genogroups related to year of isolation (G2 and G3). All new Saudi Arabia viruses clustered with the European strains, while the old strains clustered with strains from China and America. Based on amino acids and nucleotide sequences, the Saudi Arabia strains (RHD/1/SA/2012, RHD/2/SA/2012, and RHD/3/SA /2013) had high identity with Mexico89, Ca11-ITA, and 00-13,FRA virus; on the other hand, there was a relatively high identity with Bahrain strain. The evolutionary relationship of Saudi RHDVs strains revealed significant nucleotides and amino acid substitutions in hypervariable region E, suggesting the emergence of new RHDVs circulating in Saudi Arabia rabbitries. These antigenic changes represented by the antigenic index might be a potential cause of vaccination failure and raises the need to review the vaccination strategies against RHD.

Are disease reservoirs special? Taxonomic and life history characteristics

PubMed Central

Burgess, Tristan L.; Eskew, Evan A.; Roth, Tara M.; Stephenson, Nicole; Foley, Janet E.

2017-01-01

Pathogens that spill over between species cause a significant human and animal health burden. Here, we describe characteristics of animal reservoirs that are required for pathogen spillover. We assembled and analyzed a database of 330 disease systems in which a pathogen spills over from a reservoir of one or more species. Three-quarters of reservoirs included wildlife, and 84% included mammals. Further, 65% of pathogens depended on a community of reservoir hosts, rather than a single species, for persistence. Among mammals, the most frequently identified reservoir hosts were rodents, artiodactyls, and carnivores. The distribution among orders of mammalian species identified as reservoirs did not differ from that expected by chance. Among disease systems with high priority pathogens and epidemic potential, we found birds, primates, and bats to be overrepresented. We also analyzed the life history traits of mammalian reservoir hosts and compared them to mammals as a whole. Reservoir species had faster life history characteristics than mammals overall, exhibiting traits associated with greater reproductive output rather than long-term survival. Thus, we find that in many respects, reservoirs of spillover pathogens are indeed special. The described patterns provide a useful resource for studying and managing emerging infectious diseases. PMID:28704402

Shared and organism-specific host responses to childhood diarrheal diseases revealed by whole blood transcript profiling.

PubMed

DeBerg, Hannah A; Zaidi, Mussaret B; Altman, Matthew C; Khaenam, Prasong; Gersuk, Vivian H; Campos, Freddy D; Perez-Martinez, Iza; Meza-Segura, Mario; Chaussabel, Damien; Banchereau, Jacques; Estrada-Garcia, Teresa; Linsley, Peter S

2018-01-01

Globally, diarrheal diseases are a leading cause of death in children under five and disproportionately affect children in developing countries. Children who contract diarrheal diseases are rarely screened to identify the etiologic agent due to time and cost considerations associated with pathogen-specific screening and hence pathogen-directed therapy is uncommon. The development of biomarkers to rapidly identify underlying pathogens could improve treatment options and clinical outcomes in childhood diarrheal diseases. Here, we perform RNA sequencing on blood samples collected from children evaluated in an emergency room setting with diarrheal disease where the pathogen(s) present are known. We determine host response gene signatures specific to Salmonella, Shigella and rotavirus, but not E. coli, infections that distinguish them from each other and from healthy controls. Specifically, we observed differential expression of genes related to chemokine receptors or inflammasome signaling in Shigella cases, such as CCR3, CXCR8, and NLRC4, and interferon response genes, such as IFI44 and OASL, in rotavirus cases. Our findings add insight into the host peripheral immune response to these pathogens, and suggest strategies and limitations for the use host response transcript signatures for diagnosing the etiologic agent of childhood diarrheal diseases.

InvA protein is a Nudix hydrolase required for infection by pathogenic Leptospira in cell lines and animals.

PubMed

Luo, Yihui; Liu, Yan; Sun, Dexter; Ojcius, David M; Zhao, Jinfang; Lin, Xuai; Wu, Dong; Zhang, Rongguang; Chen, Ming; Li, Lanjuan; Yan, Jie

2011-10-21

Leptospirosis caused by pathogenic species of the genus Leptospira is a re-emerging zoonotic disease, which affects a wide variety of host species and is transmitted by contaminated water. The genomes of several pathogenic Leptospira species contain a gene named invA, which contains a Nudix domain. However, the function of this gene has never been characterized. Here, we demonstrated that the invA gene was highly conserved in protein sequence and present in all tested pathogenic Leptospira species. The recombinant InvA protein of pathogenic L. interrogans strain Lai hydrolyzed several specific dinucleoside oligophosphate substrates, reflecting the enzymatic activity of Nudix in Leptospira species. Pathogenic leptospires did not express this protein in media but temporarily expressed it at early stages (within 60 min) of infection of macrophages and nephric epithelial cells. Comparing with the wild type, the invA-deficient mutant displayed much lower infectivity and a significantly reduced survival rate in macrophages and nephric epithelial cells. Moreover, the invA-deficient leptospires presented an attenuated virulence in hamsters, caused mild histopathological damage, and were transmitted in lower numbers in the urine, compared with the wild-type strain. The invA revertant, made by complementing the invA-deficient mutant with the invA gene, reacquired virulence similar to the wild type in vitro and in vivo. The LD(50) in hamsters was 1000-fold higher for the invA-deficient mutant than for the invA revertant and wild type. These results demonstrate that the InvA protein is a Nudix hydrolase, and the invA gene is essential for virulence in pathogenic Leptospira species.

In Vitro Assessment of the Probiotic Potential of Lactococcus lactis LMG 7930 against Ruminant Mastitis-Causing Pathogens.

PubMed

Armas, Federica; Camperio, Cristina; Marianelli, Cinzia

2017-01-01

Mastitis in dairy ruminants is considered to be the most expensive disease to farmers worldwide. Recently, the intramammary infusion of lactic acid bacteria has emerged as a potential new alternative to antibiotics for preventing and treating bovine mastitis. In this study we have investigated in vitro the probiotic potential of Lactococcus lactis LMG 7930, a food-grade and nisin-producing strain, against mastitis-causing pathogens. We have characterized its carbohydrate fermentation and antibiotic susceptibility profiles, cell surface properties and antimicrobial activity, as well as its capabilities to adhere to and inhibit the invasion of pathogens into the bovine mammary epithelial cell line BME-UV1d. We found that L. lactis LMG 7930 was sensitive to tested drugs, according to the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), and showed an improved carbohydrate fermentation capacity compared to starter strains. Moreover, the strain exhibited antagonistic properties towards many of the pathogens tested. It presented medium surface hydrophobicity, a low basic property and no electron acceptor capability. It showed low auto-aggregation and no co-aggregation abilities towards any of the tested pathogens. The strain was one of the most adhesive to bovine mammary epithelial cells among tested bacteria, but its internalisation was low. The strain did not affect significantly pathogen invasion; however, a trend to decrease internalization of some pathogens tested was observed. In conclusion, our results suggest that this strain might be a promising candidate for the development of new strategies of mastitis control in ruminants. Future investigations are needed to evaluate its safety and efficacy under field conditions.

In Vitro Assessment of the Probiotic Potential of Lactococcus lactis LMG 7930 against Ruminant Mastitis-Causing Pathogens

PubMed Central

Armas, Federica; Camperio, Cristina

2017-01-01

Mastitis in dairy ruminants is considered to be the most expensive disease to farmers worldwide. Recently, the intramammary infusion of lactic acid bacteria has emerged as a potential new alternative to antibiotics for preventing and treating bovine mastitis. In this study we have investigated in vitro the probiotic potential of Lactococcus lactis LMG 7930, a food-grade and nisin-producing strain, against mastitis-causing pathogens. We have characterized its carbohydrate fermentation and antibiotic susceptibility profiles, cell surface properties and antimicrobial activity, as well as its capabilities to adhere to and inhibit the invasion of pathogens into the bovine mammary epithelial cell line BME-UV1d. We found that L. lactis LMG 7930 was sensitive to tested drugs, according to the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), and showed an improved carbohydrate fermentation capacity compared to starter strains. Moreover, the strain exhibited antagonistic properties towards many of the pathogens tested. It presented medium surface hydrophobicity, a low basic property and no electron acceptor capability. It showed low auto-aggregation and no co-aggregation abilities towards any of the tested pathogens. The strain was one of the most adhesive to bovine mammary epithelial cells among tested bacteria, but its internalisation was low. The strain did not affect significantly pathogen invasion; however, a trend to decrease internalization of some pathogens tested was observed. In conclusion, our results suggest that this strain might be a promising candidate for the development of new strategies of mastitis control in ruminants. Future investigations are needed to evaluate its safety and efficacy under field conditions. PMID:28068371

Genetic variation underlying resistance to infectious hematopoietic necrosis virus in a steelhead trout (Oncorhynchus mykiss) population

USGS Publications Warehouse

Brieuc, Marine S. O.; Purcell, Maureen K.; Palmer, Alexander D.; Naish, Kerry A.

2015-01-01

Understanding the mechanisms of host resistance to pathogens will allow insights into the response of wild populations to the emergence of new pathogens. Infectious hematopoietic necrosis virus (IHNV) is endemic to the Pacific Northwest and infectious to Pacific salmon and trout (Oncorhynchus spp.). Emergence of the M genogroup of IHNV in steelhead trout O. mykiss in the coastal streams of Washington State, between 2007 and 2011, was geographically heterogeneous. Differences in host resistance due to genetic change were hypothesized to be a factor influencing the IHNV emergence patterns. For example, juvenile steelhead trout losses at the Quinault National Fish Hatchery (QNFH) were much lower than those at a nearby facility that cultures a stock originally derived from the same source population. Using a classical quantitative genetic approach, we determined the potential for the QNFH steelhead trout population to respond to selection caused by the pathogen, by estimating the heritability for 2 traits indicative of IHNV resistance, mortality (h2 = 0.377 (0.226 - 0.550)) and days to death (h2 = 0.093 (0.018 - 0.203)). These results confirm that there is a genetic basis for resistance and that this population has the potential to adapt to IHNV. Additionally, genetic correlation between days to death and fish length suggests a correlated response in these traits to selection. Reduction of genetic variation, as well as the presence or absence of resistant alleles, could affect the ability of populations to adapt to the pathogen. Identification of the genetic basis for IHNV resistance could allow the assessment of the susceptibility of other steelhead populations.

Pathogenesis, Transmissibility, and Ocular Tropism of a Highly Pathogenic Avian Influenza A (H7N3) Virus Associated with Human Conjunctivitis

PubMed Central

Belser, Jessica A.; Davis, C. Todd; Balish, Amanda; Edwards, Lindsay E.; Zeng, Hui; Maines, Taronna R.; Gustin, Kortney M.; Martínez, Irma López; Fasce, Rodrigo; Cox, Nancy J.; Katz, Jacqueline M.

2013-01-01

H7 subtype influenza A viruses, responsible for numerous outbreaks in land-based poultry in Europe and the Americas, have caused over 100 cases of confirmed or presumed human infection over the last decade. The emergence of a highly pathogenic avian influenza H7N3 virus in poultry throughout the state of Jalisco, Mexico, resulting in two cases of human infection, prompted us to examine the virulence of this virus (A/Mexico/InDRE7218/2012 [MX/7218]) and related avian H7 subtype viruses in mouse and ferret models. Several high- and low-pathogenicity H7N3 and H7N9 viruses replicated efficiently in the respiratory tract of mice without prior adaptation following intranasal inoculation, but only MX/7218 virus caused lethal disease in this species. H7N3 and H7N9 viruses were also detected in the mouse eye following ocular inoculation. Virus from both H7N3 and H7N9 subtypes replicated efficiently in the upper and lower respiratory tracts of ferrets; however, only MX/7218 virus infection caused clinical signs and symptoms and was capable of transmission to naive ferrets in a direct-contact model. Similar to other highly pathogenic H7 viruses, MX/7218 replicated to high titers in human bronchial epithelial cells, yet it downregulated numerous genes related to NF-κB-mediated signaling transduction. These findings indicate that the recently isolated North American lineage H7 subtype virus associated with human conjunctivitis is capable of causing severe disease in mice and spreading to naive-contact ferrets, while concurrently retaining the ability to replicate within ocular tissue and allowing the eye to serve as a portal of entry. PMID:23487452

Multi-omics Analysis Sheds Light on the Evolution and the Intracellular Lifestyle Strategies of Spotted Fever Group Rickettsia spp.

PubMed

El Karkouri, Khalid; Kowalczewska, Malgorzata; Armstrong, Nicholas; Azza, Said; Fournier, Pierre-Edouard; Raoult, Didier

2017-01-01

Arthropod-borne Rickettsia species are obligate intracellular bacteria which are pathogenic for humans. Within this genus, Rickettsia slovaca and Rickettsia conorii cause frequent and potentially severe infections, whereas Rickettsia raoultii and Rickettsia massiliae cause rare and milder infections. All four species belong to spotted fever group (SFG) rickettsiae. However, R. slovaca and R. raoultii cause scalp eschar and neck lymphadenopathy (SENLAT) and are mainly associated with Dermacentor ticks, whereas the other two species cause Mediterranean spotted fever (MSF) and are mainly transmitted by Rhipicephalus ticks. To identify the potential genes and protein profiles and to understand the evolutionary processes that could, comprehensively, relate to the differences in virulence and pathogenicity observed between these four species, we compared their genomes and proteomes. The virulent and milder agents displayed divergent phylogenomic evolution in two major clades, whereas either SENLAT or MSF disease suggests a discrete convergent evolution of one virulent and one milder agent, despite their distant genetic relatedness. Moreover, the two virulent species underwent strong reductive genomic evolution and protein structural variations, as well as a probable loss of plasmid(s), compared to the two milder species. However, an abundance of mobilome genes was observed only in the less pathogenic species. After infecting Xenopus laevis cells, the virulent agents displayed less up-regulated than down-regulated proteins, as well as less number of identified core proteins. Furthermore, their similar and distinct protein profiles did not contain some genes (e.g., omp A/B and rick A) known to be related to rickettsial adhesion, motility and/or virulence, but may include other putative virulence-, antivirulence-, and/or disease-related proteins. The identified evolutionary forces herein may have a strong impact on intracellular expressions and strategies in these rickettsiae, and that may contribute to the emergence of distinct virulence and diseases in humans. Thus, the current multi-omics data provide new insights into the evolution and fitness of SFG virulence and pathogenicity, and intracellular pathogenic bacteria.

Novel aptamer-linked nanoconjugate approach for detection of waterborne bacterial pathogens: an update

NASA Astrophysics Data System (ADS)

Singh, Gulshan; Manohar, Murli; Adegoke, Anthony Ayodeji; Stenström, Thor Axel; Shanker, Rishi

2017-01-01

The lack of microbiologically safe water in underdeveloped nations is the prime cause of infectious disease outbreaks. The need for the specific identification and detection of microorganisms encourages the development of advanced, rapid, sensitive and highly specific methods for the monitoring of pathogens and management of potential risk to human health. The rapid molecular assays based on detection of specific molecular signatures offer advantages over conventional methods in terms of specificity and sensitivity but require complex instrumentation and skilled personnel. Nanotechnology is an emerging area and provides a robust approach for the identification of pathogenic microorganism utilizing the peculiar properties of nanomaterials, i.e. small size (1-100 nm) and large surface area. This emerging technology promises to fulfill the urgent need of a novel strategy to enhance the bacterial identification and quantitation in the environment. In this context, the peculiar properties of gold nanoparticles, their plasmonic shifts, and changes in magnetic properties have been utilized for the simple and cost-effective detection of bacterial nucleic acids, antigens and toxins with quite improved sensitivity. One of the promising leads to develop an advance detection method might be the coupling of nucleic acid aptamers (capable of interacting specifically with bacteria, protozoa, and viruses) with nanomaterials. Such aptamer-nano conjugate can be used for the specific recognition of infectious agents in different environmental matrices. This review summarizes the application of nanotechnology in the area of pathogen detection and discusses the prospects of coupling nucleic acid aptamers with nanoparticles for the specific detection of targeted pathogens.

Insights on the Emergence of Mycobacterium tuberculosis from the Analysis of Mycobacterium kansasii

PubMed Central

Wang, Joyce; McIntosh, Fiona; Radomski, Nicolas; Dewar, Ken; Simeone, Roxane; Enninga, Jost; Brosch, Roland; Rocha, Eduardo P.; Veyrier, Frédéric J.; Behr, Marcel A.

2015-01-01

By phylogenetic analysis, Mycobacterium kansasii is closely related to Mycobacterium tuberculosis. Yet, although both organisms cause pulmonary disease, M. tuberculosis is a global health menace, whereas M. kansasii is an opportunistic pathogen. To illuminate the differences between these organisms, we have sequenced the genome of M. kansasii ATCC 12478 and its plasmid (pMK12478) and conducted side-by-side in vitro and in vivo investigations of these two organisms. The M. kansasii genome is 6,432,277 bp, more than 2 Mb longer than that of M. tuberculosis H37Rv, and the plasmid contains 144,951 bp. Pairwise comparisons reveal conserved and discordant genes and genomic regions. A notable example of genomic conservation is the virulence locus ESX-1, which is intact and functional in the low-virulence M. kansasii, potentially mediating phagosomal disruption. Differences between these organisms include a decreased predicted metabolic capacity, an increased proportion of toxin–antitoxin genes, and the acquisition of M. tuberculosis-specific genes in the pathogen since their common ancestor. Consistent with their distinct epidemiologic profiles, following infection of C57BL/6 mice, M. kansasii counts increased by less than 10-fold over 6 weeks, whereas M. tuberculosis counts increased by over 10,000-fold in just 3 weeks. Together, these data suggest that M. kansasii can serve as an image of the environmental ancestor of M. tuberculosis before its emergence as a professional pathogen, and can be used as a model organism to study the switch from an environmental opportunistic pathogen to a professional host-restricted pathogen. PMID:25716827

Species-specific chitin-binding module 18 expansion in the amphibian pathogen Batrachochytrium dendrobatidis.

PubMed

Abramyan, John; Stajich, Jason E

2012-01-01

Batrachochytrium dendrobatidis is the causative agent of chytridiomycosis, which is considered one of the driving forces behind the worldwide decline in populations of amphibians. As a member of the phylum Chytridiomycota, B. dendrobatidis has diverged significantly to emerge as the only pathogen of adult vertebrates. Such shifts in lifestyle are generally accompanied by various degrees of genomic modifications, yet neither its mode of pathogenicity nor any factors associated with it have ever been identified. Presented here is the identification and characterization of a unique expansion of the carbohydrate-binding module family 18 (CBM18), specific to B. dendrobatidis. CBM (chitin-binding module) expansions have been likened to the evolution of pathogenicity in a variety of fungus species, making this expanded group a prime candidate for the identification of potential pathogenicity factors. Furthermore, the CBM18 expansions are confined to three categories of genes, each having been previously implicated in host-pathogen interactions. These correlations highlight this specific domain expansion as a potential key player in the mode of pathogenicity in this unique fungus. The expansion of CBM18 in B. dendrobatidis is exceptional in its size and diversity compared to other pathogenic species of fungi, making this genomic feature unique in an evolutionary context as well as in pathogenicity. Amphibian populations are declining worldwide at an unprecedented rate. Although various factors are thought to contribute to this phenomenon, chytridiomycosis has been identified as one of the leading causes. This deadly fungal disease is cause by Batrachochytrium dendrobatidis, a chytrid fungus species unique in its pathogenicity and, furthermore, its specificity to amphibians. Despite more than two decades of research, the biology of this fungus species and its deadly interaction with amphibians had been notoriously difficult to unravel. Due to the alarming rate of worldwide spread and associated decline in amphibian populations, it is imperative to incorporate novel genomic and genetic techniques into the study of this species. In this study, we present the first reported potential pathogenicity factors in B. dendrobatidis. In silico studies such as this allow us to identify putative targets for more specific molecular analyses, furthering our hope for the control of this pathogen.

Ebolavirus: An Overview of Molecular and Clinical Pathogenesis.

PubMed

Vine, Veronica; Scott, Dana P; Feldmann, Heinz

2017-01-01

Ebolaviruses cause severe, often fatal hemorrhagic fever in Central, East, and West Africa. Until recently, they have been viewed as rare but highly pathogenic infections with regional, but limited, global public health impact. This view has changed with the emergence of the first epidemic of Ebola hemorrhagic fever in West Africa. In this chapter we provide an introduction of the pathogenesis of ebolaviruses as well as a description of clinical disease features. We also describe the current animal models used in ebolavirus research, detailing each model's unique strengths and weaknesses. We focus on Ebola virus representing the type species Zaire ebolavirus of the genus Ebolavirus, as most work relates to this pathogen.

Pathogenic genotype of major piroplasm surface protein associated with anemia in Theileria orientalis infection in cattle.

PubMed

Kim, Suhee; Yu, Do-Hyeon; Chae, Jeong-Byoung; Choi, Kyoung-Seong; Kim, Hyeon-Cheol; Park, Bae-Keun; Chae, Joon-Seok; Park, Jinho

2017-07-27

Serious disease outbreaks in cattle caused by Theileria orientalis have emerged in the Asia-Pacific region. Genetic variables of the major piroplasm surface protein (MPSP) expressed on the surface of the piroplasm inside T. orientalis-infected erythrocytes are considered to be associated with variation in the pathogenicity of T. orientalis. Our study describes the clinically relevant MPSP types associated with anemia in Theileria-infected cattle. These results revealed that MPSP expression plays an important role in hematological alterations in Theileria-infected cattle, and that MPSP type 1 is strongly associated with bovine anemia, which can be a potential target for the prevention of bovine theileriosis.

Climate change accelerates local disease extinction rates in a long-term wild host-pathogen association.

PubMed

Zhan, Jiasui; Ericson, Lars; Burdon, Jeremy J

2018-02-27

Pathogens are a significant component of all plant communities. In recent years, the potential for existing and emerging pathogens of agricultural crops to cause increased yield losses as a consequence of changing climatic patterns has raised considerable concern. In contrast, the response of naturally occurring, endemic pathogens to a warming climate has received little attention. Here, we report on the impact of a signature variable of global climate change - increasing temperature - on the long-term epidemiology of a natural host-pathogen association involving the rust pathogen Triphragmium ulmariae and its host plant Filipendula ulmaria. In a host-pathogen metapopulation involving approximately 230 host populations growing on an archipelago of islands in the Gulf of Bothnia we assessed changes in host population size and pathogen epidemiological measures over a 25-year period. We show how the incidence of disease and its severity declines over that period and most importantly demonstrate a positive association between a long-term trend of increasing extinction rates in individual pathogen populations of the metapopulation and increasing temperature. Our results are highly suggestive that changing climatic patterns, particularly mean monthly growing season (April-November) temperature, are markedly influencing the epidemiology of plant disease in this host-pathogen association. Given the important role plant pathogens have in shaping the structure of communities, changes in the epidemiology of pathogens have potentially far-reaching impacts on ecological and evolutionary processes. For these reasons, it is essential to increase understanding of pathogen epidemiology, its response to warming, and to invoke these responses in forecasts for the future. © 2018 John Wiley & Sons Ltd.

Emerging Tuberculosis Pathogen Hijacks Social Communication Behavior in the Group-Living Banded Mongoose (Mungos mungo).

PubMed

Alexander, Kathleen A; Sanderson, Claire E; Larsen, Michelle H; Robbe-Austerman, Suelee; Williams, Mark C; Palmer, Mitchell V

2016-05-10

An emerging Mycobacterium tuberculosis complex (MTC) pathogen, M. mungi, infects wild banded mongooses (Mungos mungo) in Northern Botswana, causing significant mortality. This MTC pathogen did not appear to be transmitted through a primary aerosol or oral route. We utilized histopathology, spoligotyping, mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR), quantitative PCR (qPCR), and molecular markers (regions of difference [RDs] from various MTC members, including region of difference 1 [RD1] from M. bovis BCG [RD1(BCG)], M. microti [RD1(mic)], and M. pinnipedii [RD1(seal)], genes Rv1510 [RD4], Rv1970 [RD7], Rv3877/8 [RD1], and Rv3120 [RD12], insertion element IS1561, the 16S RNA gene, and gene Rv0577 [cfp32]), including the newly characterized mongoose-specific deletion in RD1 (RD1(mon)), in order to demonstrate the presence of M. mungi DNA in infected mongooses and investigate pathogen invasion and exposure mechanisms. M. mungi DNA was identified in 29% of nasal planum samples (n = 52), 56% of nasal rinses and swabs (n = 9), 53% of oral swabs (n = 19), 22% of urine samples (n = 23), 33% of anal gland tissue (n = 18), and 39% of anal gland secretions (n = 44). The occurrence of extremely low cycle threshold values obtained with qPCR in anal gland and nasal planum samples indicates that high levels of M. mungi can be found in these tissue types. Histological data were consistent with these results, suggesting that pathogen invasion occurs through breaks in the nasal planum and/or skin of the mongoose host, which are in frequent contact with anal gland secretions and urine during olfactory communication behavior. Lesions in the lung, when present, occurred only with disseminated disease. No environmental sources of M. mungi DNA could be found. We report primary environmental transmission of an MTC pathogen that occurs in association with social communication behavior. Organisms causing infectious disease evolve modes of transmission that exploit environmental and host conditions favoring pathogen spread and persistence. We report a novel mode of environmental infectious disease transmission that occurs in association with olfactory secretions (e.g., urine and anal gland secretions), allowing pathogen exposure to occur within and between social groups through intricate social communication behaviors of the banded mongoose host. The presence of M. mungi in these environmentally deposited secretions would effectively circumvent natural social barriers (e.g., territoriality), facilitating between-group pathogen transmission in the absence of direct physical contact, a rare occurrence in this highly territorial species. This work identifies an important potential mechanism of pathogen transmission of epidemiological significance in social species. We also provide evidence of a novel mechanism of pathogen transmission for the MTC complex, where pathogen movement in the environment and host exposure dynamics are driven by social behavior. Copyright © 2016 Alexander et al.

Acute diarrhea during army field exercise in southern China

PubMed Central

Bai, Yang; Dai, Ying-Chun; Li, Jian-Dong; Nie, Jun; Chen, Qing; Wang, Hong; Rui, Yong-Yu; Zhang, Ya-Li; Yu, Shou-Yi

2004-01-01

AIM: During emergency period, infectious diseases can be a major threat to military forces. During field training in southern China, diarrhea is the main cause of nonbattle injury. To evaluate the causes of and risk factors for diarrhea in emergency period, we collected clinical and epidemiological data from the People’s Liberation Army (PLA) during field training in southern China. METHODS: From September 25 to October 2 1997, 2636 military personnel were investigated. Fecal sample cultures for lapactic pathogens were obtained from 103 military personnel with diarrhea. In addition, a questionnaire was administered to 103 cases and 206 controls to evaluate the association between illness and potential risk factors. At the same time, another questionnaire of 1:4 case-case control was administered to 22 severe cases (each severe case paired 4 mild cases). RESULTS: The training troop’s diarrhea incidence rate was significantly higher than that of garrison. The diarrhea incidence rate of officers was significantly lower than that of soldiers. A lapactic pathogen was identified in 63.1% (65/103) of the troops with diarrhea. Enterotoxigenic Escherichia coli (35.0%) and plesiomona shigelloides (16.5%) were the most common bacterial pathogens. All bacterial isolates were sensitive to norfloxacin and ceftazidine. However, almost all of them were resistant to sulfamethoxazole, trimethoprim-sulfamethoxazole, oxytetracycline, doxycycline, furazolidone, ampicillin and cloromycetin to a different degree. Risk factors associated with diarrhea included drinking raw water, eating outside, contacting diarrhea patients, lacking sanitation, depression, lacking sleep, which were established by multiple-factor logistic regression analysis. In addition, the unit incidence rate was associated with the density of flies and the average daily boiled water available by regression and discriminate analysis. CONCLUSION: A series of risk factors are associated with the incidence rate of diarrhea. Our results may provide a useful basis for prevention and cure of diarrhea in emergency period of PLA. PMID:14695783

Rethinking the Response to Emerging Microbes: Vaccines and Therapeutics in the Ebola Era--a Conference at Harvard Medical School.

PubMed

Knipe, David M; Whelan, Sean P

2015-08-01

Harvard Medical School convened a meeting of biomedical and clinical experts on 5 March 2015 on the topic of "Rethinking the Response to Emerging Microbes: Vaccines and Therapeutics in the Ebola Era," with the goals of discussing the lessons from the recent Ebola outbreak and using those lessons as a case study to aid preparations for future emerging infections. The speakers and audience discussed the special challenges in combatting an infectious agent that causes sporadic outbreaks in resource-poor countries. The meeting led to a call for improved basic medical care for all and continued support of basic discovery research to provide the foundation for preparedness for future outbreaks in addition to the targeted emergency response to outbreaks and targeted research programs against Ebola virus and other specific emerging pathogens. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Rapid and Accurate Molecular Identification of the Emerging Multidrug-Resistant Pathogen Candida auris

PubMed Central

Zhao, Yanan; Lockhart, Shawn R.; Berrio, Indira

2017-01-01

ABSTRACT Candida auris is an emerging multidrug-resistant fungal pathogen causing nosocomial and invasive infections associated with high mortality. C. auris is commonly misidentified as several different yeast species by commercially available phenotypic identification platforms. Thus, there is an urgent need for a reliable diagnostic method. In this paper, we present fast, robust, easy-to-perform and interpret PCR and real-time PCR assays to identify C. auris and related species: Candida duobushaemulonii, Candida haemulonii, and Candida lusitaniae. Targeting rDNA region nucleotide sequences, primers specific for C. auris only or C. auris and related species were designed. A panel of 140 clinical fungal isolates was used in both PCR and real-time PCR assays followed by electrophoresis or melting temperature analysis, respectively. The identification results from the assays were 100% concordant with DNA sequencing results. These molecular assays overcome the deficiencies of existing phenotypic tests to identify C. auris and related species. PMID:28539346

Streptococcus suis: a new emerging or an old neglected zoonotic pathogen?

PubMed

Gottschalk, Marcelo; Xu, Jianguo; Calzas, Cynthia; Segura, Mariela

2010-03-01

Infections caused by Streptococcus suis are considered a global and an economical problem in the swine industry. Moreover, S. suis is an agent of zoonosis that afflicts people in close contact with infected pigs or pork-derived products. Although sporadic cases of S. suis infections in humans (mainly meningitis) have been reported during the last 40 years, a large outbreak due to this pathogen emerged in the summer of 2005 in China. The severity of the infection in humans during the outbreak, such as a shorter incubation time, more rapid disease progression and higher rate of mortality, attracted a lot of attention from the scientific community and the general press. In fact, the number of publications on S. suis (including the number of reported human cases) has significantly increased during recent years. In this article we critically review the present knowledge on S. suis infection in humans, we discuss the hypotheses that may explain the 2005 outbreak and the repercussion of such an episode on the scientific community.

Rapid and Accurate Molecular Identification of the Emerging Multidrug-Resistant Pathogen Candida auris.

PubMed

Kordalewska, Milena; Zhao, Yanan; Lockhart, Shawn R; Chowdhary, Anuradha; Berrio, Indira; Perlin, David S

2017-08-01

Candida auris is an emerging multidrug-resistant fungal pathogen causing nosocomial and invasive infections associated with high mortality. C. auris is commonly misidentified as several different yeast species by commercially available phenotypic identification platforms. Thus, there is an urgent need for a reliable diagnostic method. In this paper, we present fast, robust, easy-to-perform and interpret PCR and real-time PCR assays to identify C. auris and related species: Candida duobushaemulonii , Candida haemulonii , and Candida lusitaniae Targeting rDNA region nucleotide sequences, primers specific for C. auris only or C. auris and related species were designed. A panel of 140 clinical fungal isolates was used in both PCR and real-time PCR assays followed by electrophoresis or melting temperature analysis, respectively. The identification results from the assays were 100% concordant with DNA sequencing results. These molecular assays overcome the deficiencies of existing phenotypic tests to identify C. auris and related species. Copyright © 2017 Kordalewska et al.

Rhodotorula fungemia: Report of two cases in Sfax (Tunisia).

PubMed

Guidara, R; Trabelsi, H; Neji, S; Cheikhrouhou, F; Sellami, H; Makni, F; Ayadi, A

2016-06-01

Rhodotorula is emerging as an important cause of nosocomial and opportunistic infections. We present two cases of Rhodotorula mucilaginosa fungemia diagnosed at our hospital during the last decade. The first case was of a term neonate who presented congenital heart disease (interventricular communication) and body dysmorphic disorder. He was admitted for respiratory failure and sepsis. The second case involved in a 33-year-old woman that had Hodgkinien lymphoma associated to tuberculosis. Identification was performed using commercial systems and confirmed by PCR sequencing of internal transcribed spacer, ITS1 and ITS2 regions of rDNA. Antifungal susceptibility tested by sensititre yeast revealed susceptibility to amphotericin B and resistance to fluconazole for the two strains. These cases emphasize the emerging importance of Rhodotorula sp. as a pathogen and it must be considered a potential pathogen in patients with immunosupression and with central venous catheters. Correct identification is mandatory for appropriate management, as Rhodotorula spp. are resistant to antifungal agents, such as fluconazole. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Recently Identified Mutations in the Ebola Virus-Makona Genome Do Not Alter Pathogenicity in Animal Models.

PubMed

Marzi, Andrea; Chadinah, Spencer; Haddock, Elaine; Feldmann, Friederike; Arndt, Nicolette; Martellaro, Cynthia; Scott, Dana P; Hanley, Patrick W; Nyenswah, Tolbert G; Sow, Samba; Massaquoi, Moses; Feldmann, Heinz

2018-05-08

Ebola virus (EBOV), isolate Makona, the causative agent of the West African EBOV epidemic, has been the subject of numerous investigations to determine the genetic diversity and its potential implication for virus biology, pathogenicity, and transmissibility. Despite various mutations that have emerged over time through multiple human-to-human transmission chains, their biological relevance remains questionable. Recently, mutations in the glycoprotein GP and polymerase L, which emerged and stabilized early during the outbreak, have been associated with improved viral fitness in cell culture. Here, we infected mice and rhesus macaques with EBOV-Makona isolates carrying or lacking those mutations. Surprisingly, all isolates behaved very similarly independent of the genotype, causing severe or lethal disease in mice and macaques, respectively. Likewise, we could not detect any evidence for differences in virus shedding. Thus, no specific biological phenotype could be associated with these EBOV-Makona mutations in two animal models. Published by Elsevier Inc.

Olive anthracnose: a yield- and oil quality-degrading disease caused by several species of Colletotrichum that differ in virulence, host preference and geographical distribution.

PubMed

Talhinhas, Pedro; Loureiro, Andreia; Oliveira, Helena

2018-03-08

Olive anthracnose causes fruit rot leading to its drop or mummification, resulting in yield losses and the degradation of oil quality. The disease is caused by diverse species of Colletotrichum, mostly clustering in the C. acutatum species complex. Colletotrichum nymphaeae and C. godetiae are the prevalent species in the Northern Hemisphere, whereas C. acutatum sensu stricto is the most frequent species in the Southern Hemisphere, although it is recently and quickly emerging in the Northern Hemisphere. The disease has been reported from all continents, but it attains higher incidence and severity in the west of the Mediterranean Basin, where it is endemic in traditional orchards of susceptible cultivars. The pathogens are able to survive on vegetative organs. On the fruit surface, infections remain quiescent until fruit maturity, when typical anthracnose symptoms develop. Under severe epidemics, defoliation and death of branches can also occur. Pathogen species differ in virulence, although this depends on the cultivar. The selection of resistant cultivars depends strongly on pathogen diversity and environmental conditions, posing added difficulties to breeding efforts. Chemical disease control is normally achieved with copper-based fungicides, although this may be insufficient under highly favourable disease conditions and causes concern because of the presence of fungicide residues in the oil. In areas in which the incidence is high, farmers tend to anticipate harvest, with consequences in yield and oil characteristics. Olive production systems, harvest and post-harvest processing have experienced profound changes in recent years, namely new training systems using specific cultivars, new harvest and processing techniques and new organoleptic market requests. Changes are also occurring in both the geographical distribution of pathogen populations and the taxonomic framework. In addition, stricter rules concerning pesticide use are likely to have a strong impact on control strategies. A detailed knowledge of pathogen diversity, population dynamics and host-pathogen interactions is basal for the deployment of durable and effective disease control strategies, whether based on resistance breeding, agronomic practices or biological or chemical control. © 2018 BSPP AND JOHN WILEY & SONS LTD.

Genomic characterisation of an endometrial pathogenic Escherichia coli strain reveals the acquisition of genetic elements associated with extra-intestinal pathogenicity.

PubMed

Goldstone, Robert J; Popat, Roman; Schuberth, Hans-Joachim; Sandra, Olivier; Sheldon, I Martin; Smith, David G E

2014-12-06

Strains of Escherichia coli cause a wide variety of intestinal and extra-intestinal diseases in both humans and animals, and are also often found in healthy individuals or the environment. Broadly, a strong phylogenetic relationship exists that distinguishes most E. coli causing intestinal disease from those that cause extra-intestinal disease, however, isolates within a recently described subclass of Extra-Intestinal Pathogenic E. coli (ExPEC), termed endometrial pathogenic E. coli, tend to be phylogenetically distant from the vast majority of characterised ExPECs, and more closely related to human intestinal pathogens. In this work, we investigate the genetic basis for ExPEC infection in the prototypic endometrial pathogenic E. coli strain MS499. By investigating the genome of MS499 in comparison with a range of other E. coli sequences, we have discovered that this bacterium has acquired substantial lengths of DNA which encode factors more usually associated with ExPECs and less frequently found in the phylogroup relatives of MS499. Many of these acquired factors, including several iron acquisition systems and a virulence plasmid similar to that found in several ExPECs such as APEC O1 and the neonatal meningitis E. coli S88, play characterised roles in a variety of typical ExPEC infections and appear to have been acquired recently by the evolutionary lineage leading to MS499. Taking advantage of the phylogenetic relationship we describe between MS499 and several other closely related E. coli isolates from across the globe, we propose a step-wise evolution of a novel clade of sequence type 453 ExPECs within phylogroup B1, involving the recruitment of ExPEC virulence factors into the genome of an ancestrally non-extraintestinal E. coli, which has repurposed this lineage with the capacity to cause extraintestinal disease. These data reveal the genetic components which may be involved in this phenotype switching, and argue that horizontal gene exchange may be a key factor in the emergence of novel lineages of ExPECs.

What's hot in animal biosafety?

PubMed

Richmond, J Y; Hill, R H; Weyant, R S; Nesby-O'Dell, S L; Vinson, P E

2003-01-01

In recent years, the emergence or re-emergence of critical issues in infectious disease and public health has presented new challenges and opportunities for laboratory animal care professionals. The re-emergence of bioterrorism as a threat activity of individuals or small groups has caused a heightened awareness of biosecurity and improved biosafety. The need for animal work involving high-risk or high-consequence pathogens and for arthropod-borne diseases has stimulated renewed interest in animal biosafety matters, particularly for work in containment. Application of these principles to animals retained in outdoor environments has been a consequence of disease eradication programs. The anticipated global eradication of wild poliovirus has prompted the promulgation of new biosafety guidelines for future laboratory and animal work. Increased concern regarding the use of biologically derived toxins and hazardous chemicals has stimulated a new categorization of facility containment based on risk assessment. Recognition that prion disease agents and other high-consequence pathogens require safe handling and thorough destruction during terminal decontamination treatment has led to the development of new biosafety guidelines and technologies. The implementation of these guidelines and technologies will promote state-of-the-art research while minimizing risk to laboratory animals, researchers, and the environment.

Role of the horizontal gene exchange in evolution of pathogenic Mycobacteria.

PubMed

Reva, Oleg; Korotetskiy, Ilya; Ilin, Aleksandr

2015-01-01

Mycobacterium tuberculosis is one of the most dangerous human pathogens, the causative agent of tuberculosis. While this pathogen is considered as extremely clonal and resistant to horizontal gene exchange, there are many facts supporting the hypothesis that on the early stages of evolution the development of pathogenicity of ancestral Mtb has started with a horizontal acquisition of virulence factors. Episodes of infections caused by non-tuberculosis Mycobacteria reported worldwide may suggest a potential for new pathogens to appear. If so, what is the role of horizontal gene transfer in this process? Availing of accessibility of complete genomes sequences of multiple pathogenic, conditionally pathogenic and saprophytic Mycobacteria, a genome comparative study was performed to investigate the distribution of genomic islands among bacteria and identify ontological links between these mobile elements. It was shown that the ancient genomic islands from M. tuberculosis still may be rooted to the pool of mobile genetic vectors distributed among Mycobacteria. A frequent exchange of genes was observed between M. marinum and several saprophytic and conditionally pathogenic species. Among them M. avium was the most promiscuous species acquiring genetic materials from diverse origins. Recent activation of genetic vectors circulating among Mycobacteria potentially may lead to emergence of new pathogens from environmental and conditionally pathogenic Mycobacteria. The species which require monitoring are M. marinum and M. avium as they eagerly acquire genes from different sources and may become donors of virulence gene cassettes to other micro-organisms.

Genome Dynamics in Legionella: The Basis of Versatility and Adaptation to Intracellular Replication

PubMed Central

Gomez-Valero, Laura; Buchrieser, Carmen

2013-01-01

Legionella pneumophila is a bacterial pathogen present in aquatic environments that can cause a severe pneumonia called Legionnaires’ disease. Soon after its recognition, it was shown that Legionella replicates inside amoeba, suggesting that bacteria replicating in environmental protozoa are able to exploit conserved signaling pathways in human phagocytic cells. Comparative, evolutionary, and functional genomics suggests that the Legionella–amoeba interaction has shaped this pathogen more than previously thought. A complex evolutionary scenario involving mobile genetic elements, type IV secretion systems, and horizontal gene transfer among Legionella, amoeba, and other organisms seems to take place. This long-lasting coevolution led to the development of very sophisticated virulence strategies and a high level of temporal and spatial fine-tuning of bacteria host–cell interactions. We will discuss current knowledge of the evolution of virulence of Legionella from a genomics perspective and propose our vision of the emergence of this human pathogen from the environment. PMID:23732852

Survival analysis of infected mice reveals pathogenic variations in the genome of avian H1N1 viruses.

PubMed

Koçer, Zeynep A; Fan, Yiping; Huether, Robert; Obenauer, John; Webby, Richard J; Zhang, Jinghui; Webster, Robert G; Wu, Gang

2014-12-12

Most influenza pandemics have been caused by H1N1 viruses of purely or partially avian origin. Here, using Cox proportional hazard model, we attempt to identify the genetic variations in the whole genome of wild-type North American avian H1N1 influenza A viruses that are associated with their virulence in mice by residue variations, host origins of virus (Anseriformes-ducks or Charadriiformes-shorebirds), and host-residue interactions. In addition, through structural modeling, we predicted that several polymorphic sites associated with pathogenicity were located in structurally important sites, especially in the polymerase complex and NS genes. Our study introduces a new approach to identify pathogenic variations in wild-type viruses circulating in the natural reservoirs and ultimately to understand their infectious risks to humans as part of risk assessment efforts towards the emergence of future pandemic strains.

Interplay Between Antibiotic Resistance and Virulence During Disease Promoted by Multidrug-Resistant Bacteria

PubMed Central

Geisinger, Edward

2017-01-01

Abstract Diseases caused by antibiotic-resistant bacteria in hospitals are the outcome of complex relationships between several dynamic factors, including bacterial pathogenicity, the fitness costs of resistance in the human host, and selective forces resulting from interventions such as antibiotic therapy. The emergence and fate of mutations that drive antibiotic resistance are governed by these interactions. In this review, we will examine how different forms of antibiotic resistance modulate bacterial fitness and virulence potential, thus influencing the ability of pathogens to evolve in the context of nosocomial infections. We will focus on 3 important multidrug-resistant pathogens that are notoriously problematic in hospitals: Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus. An understanding of how antibiotic resistance mutations shape the pathobiology of multidrug-resistant infections has the potential to drive novel strategies that can control the development and spread of drug resistance. PMID:28375515

Assessment of Climate Change and Vector-borne Diseases in the United States

NASA Astrophysics Data System (ADS)

Monaghan, A. J.; Beard, C. B.; Eisen, R. J.; Barker, C. M.; Garofalo, J.; Hahn, M.; Hayden, M.; Ogden, N.; Schramm, P.

2016-12-01

Vector-borne diseases are illnesses that are transmitted by vectors, which include mosquitoes, ticks, and fleas. The seasonality, distribution, and prevalence of vector-borne diseases are influenced significantly by climate factors, primarily high and low temperature extremes and precipitation patterns. In this presentation we summarize key findings from Chapter 5 ("Vector-borne Diseases") of the recently published USGCRP Scientific Assessment of the Impacts of Climate Change on Human Health in the United States. Climate change is expected to alter geographic and seasonal distributions of vectors and vector-borne diseases, leading to earlier activity and northward range expansion of ticks capable of carrying the bacteria that cause Lyme disease and other pathogens, and influencing the distribution, abundance and prevalence of infection in mosquitoes that transmit West Nile virus and other pathogens. The emergence or reemergence of vector-borne pathogens is also likely.

Broad-Spectrum Molecular Detection of Fungal Nucleic Acids by PCR-Based Amplification Techniques.

PubMed

Czurda, Stefan; Lion, Thomas

2017-01-01

Over the past decade, the incidence of life-threatening invasive fungal infections has dramatically increased. Infections caused by hitherto rare and emerging fungal pathogens are associated with significant morbidity and mortality among immunocompromised patients. These observations render the coverage of a broad range of clinically relevant fungal pathogens highly important. The so-called panfungal or, perhaps more correctly, broad-range nucleic acid amplification techniques do not only facilitate sensitive detection of all clinically relevant fungal species but are also rapid and can be applied to analyses of any patient specimens. They have therefore become valuable diagnostic tools for sensitive screening of patients at risk of invasive fungal infections. This chapter summarizes the currently available molecular technologies employed in testing of a wide range of fungal pathogens, and provides a detailed workflow for patient screening by broad-spectrum nucleic acid amplification techniques.

Genome dynamics in Legionella: the basis of versatility and adaptation to intracellular replication.

PubMed

Gomez-Valero, Laura; Buchrieser, Carmen

2013-06-01

Legionella pneumophila is a bacterial pathogen present in aquatic environments that can cause a severe pneumonia called Legionnaires' disease. Soon after its recognition, it was shown that Legionella replicates inside amoeba, suggesting that bacteria replicating in environmental protozoa are able to exploit conserved signaling pathways in human phagocytic cells. Comparative, evolutionary, and functional genomics suggests that the Legionella-amoeba interaction has shaped this pathogen more than previously thought. A complex evolutionary scenario involving mobile genetic elements, type IV secretion systems, and horizontal gene transfer among Legionella, amoeba, and other organisms seems to take place. This long-lasting coevolution led to the development of very sophisticated virulence strategies and a high level of temporal and spatial fine-tuning of bacteria host-cell interactions. We will discuss current knowledge of the evolution of virulence of Legionella from a genomics perspective and propose our vision of the emergence of this human pathogen from the environment.

Genome Sequences for Five Strains of the Emerging Pathogen Haemophilus haemolyticus

PubMed Central

Jordan, I. King; Conley, Andrew B.; Antonov, Ivan V.; Arthur, Robert A.; Cook, Erin D.; Cooper, Guy P.; Jones, Bernard L.; Knipe, Kristen M.; Lee, Kevin J.; Liu, Xing; Mitchell, Gabriel J.; Pande, Pushkar R.; Petit, Robert A.; Qin, Shaopu; Rajan, Vani N.; Sarda, Shruti; Sebastian, Aswathy; Tang, Shiyuyun; Thapliyal, Racchit; Varghese, Neha J.; Ye, Tianjun; Katz, Lee S.; Wang, Xin; Rowe, Lori; Frace, Michael; Mayer, Leonard W.

2011-01-01

We report the first whole-genome sequences for five strains, two carried and three pathogenic, of the emerging pathogen Haemophilus haemolyticus. Preliminary analyses indicate that these genome sequences encode markers that distinguish H. haemolyticus from its closest Haemophilus relatives and provide clues to the identity of its virulence factors. PMID:21952546

CE-BLAST makes it possible to compute antigenic similarity for newly emerging pathogens.

PubMed

Qiu, Tianyi; Yang, Yiyan; Qiu, Jingxuan; Huang, Yang; Xu, Tianlei; Xiao, Han; Wu, Dingfeng; Zhang, Qingchen; Zhou, Chen; Zhang, Xiaoyan; Tang, Kailin; Xu, Jianqing; Cao, Zhiwei

2018-05-02

Major challenges in vaccine development include rapidly selecting or designing immunogens for raising cross-protective immunity against different intra- or inter-subtypic pathogens, especially for the newly emerging varieties. Here we propose a computational method, Conformational Epitope (CE)-BLAST, for calculating the antigenic similarity among different pathogens with stable and high performance, which is independent of the prior binding-assay information, unlike the currently available models that heavily rely on the historical experimental data. Tool validation incorporates influenza-related experimental data sufficient for stability and reliability determination. Application to dengue-related data demonstrates high harmonization between the computed clusters and the experimental serological data, undetectable by classical grouping. CE-BLAST identifies the potential cross-reactive epitope between the recent zika pathogen and the dengue virus, precisely corroborated by experimental data. The high performance of the pathogens without the experimental binding data suggests the potential utility of CE-BLAST to rapidly design cross-protective vaccines or promptly determine the efficacy of the currently marketed vaccine against emerging pathogens, which are the critical factors for containing emerging disease outbreaks.

Genomic and antigenic characterization of the newly emerging Chinese duck egg-drop syndrome flavivirus: genomic comparison with Tembusu and Sitiawan viruses.

PubMed

Liu, Peipei; Lu, Hao; Li, Shuang; Moureau, Gregory; Deng, Yong-Qiang; Wang, Yongyue; Zhang, Lijiao; Jiang, Tao; de Lamballerie, Xavier; Qin, Cheng-Feng; Gould, Ernest A; Su, Jingliang; Gao, George F

2012-10-01

Duck egg-drop syndrome virus (DEDSV) is a newly emerging pathogenic flavivirus causing avian diseases in China. The infection occurs in laying ducks characterized by a severe drop in egg production with a fatality rate of 5-15 %. The virus was found to be most closely related to Tembusu virus (TMUV), an isolate from mosquitoes in South-east Asia. Here, we have sequenced and characterized the full-length genomes of seven DEDSV strains, including the 5'- and 3'-non-coding regions (NCRs). We also report for the first time the ORF sequences of TMUV and Sitiawan virus (STWV), another closely related flavivirus isolated from diseased chickens. We analysed the phylogenetic and antigenic relationships of DEDSV in relation to the Asian viruses TMUV and STWV, and other representative flaviviruses. Our results confirm the close relationship between DEDSV and TMUV/STWV and we discuss their probable evolutionary origins. We have also characterized the cleavage sites, potential glycosylation sites and unique motifs/modules of these viruses. Additionally, conserved sequences in both 5'- and 3'-NCRs were identified and the predicted secondary structures of the terminal sequences were studied. Antigenic cross-reactivity comparisons of DEDSV with related pathogenic flaviviruses identified a surprisingly close relationship with dengue virus (DENV) and raised the question of whether or not DEDSV may have a potential infectious threat to man. Importantly, DEDSV can be efficiently recognized by a broadly cross-reactive flavivirus mAb, 2A10G6, derived against DENV. The significance of these studies is discussed in the context of the emergence, evolution, epidemiology, antigenicity and pathogenicity of the newly emergent DEDSV.

A Permutation-Randomization Approach to Test the Spatial Distribution of Plant Diseases.

PubMed

Lione, G; Gonthier, P

2016-01-01

The analysis of the spatial distribution of plant diseases requires the availability of trustworthy geostatistical methods. The mean distance tests (MDT) are here proposed as a series of permutation and randomization tests to assess the spatial distribution of plant diseases when the variable of phytopathological interest is categorical. A user-friendly software to perform the tests is provided. Estimates of power and type I error, obtained with Monte Carlo simulations, showed the reliability of the MDT (power > 0.80; type I error < 0.05). A biological validation on the spatial distribution of spores of two fungal pathogens causing root rot on conifers was successfully performed by verifying the consistency between the MDT responses and previously published data. An application of the MDT was carried out to analyze the relation between the plantation density and the distribution of the infection of Gnomoniopsis castanea, an emerging fungal pathogen causing nut rot on sweet chestnut. Trees carrying nuts infected by the pathogen were randomly distributed in areas with different plantation densities, suggesting that the distribution of G. castanea was not related to the plantation density. The MDT could be used to analyze the spatial distribution of plant diseases both in agricultural and natural ecosystems.

The pathogenicity of Aspergillus fumigatus, drug resistance, and nanoparticle delivery.

PubMed

Szalewski, David A; Hinrichs, Victoria S; Zinniel, Denise K; Barletta, Raúl G

2018-03-27

The genus Aspergillus includes fungal species that cause major health issues of significant economic importance. These microorganisms are also the culprit for production of carcinogenic aflatoxins in grain storages, contaminating crops, and economically straining the production process. Aspergillus fumigatus is a very important pathogenic species, being responsible for high human morbidity and mortality on a global basis. The prevalence of these infections in immunosuppressed individuals is on the rise, and physicians struggle with the diagnosis of these deadly pathogens. Several virulence determinants facilitate fungal invasion and evasion of the host immune response. Metabolic functions are also important for virulence and drug resistance, since they allow fungi to obtain nutrients for their own survival and growth. Following a positive diagnostic identification, mortality rates remain high due, in part, to emerging resistance to frequently used antifungal drugs. In this review, we discuss the role of the main virulence, drug target, and drug resistance determinants. We conclude with the review of new technologies being developed to treat aspergillosis. In particular, microsphere and nanoparticle delivery systems are discussed in the context of improving drug bioavailability. Aspergillus will likely continue to cause problematic infections in immunocompromised patients, so it is imperative to improve treatment options.

Sessile alveolar macrophages communicate with alveolar epithelium to modulate immunity

NASA Astrophysics Data System (ADS)

Westphalen, Kristin; Gusarova, Galina A.; Islam, Mohammad N.; Subramanian, Manikandan; Cohen, Taylor S.; Prince, Alice S.; Bhattacharya, Jahar

2014-02-01

The tissue-resident macrophages of barrier organs constitute the first line of defence against pathogens at the systemic interface with the ambient environment. In the lung, resident alveolar macrophages (AMs) provide a sentinel function against inhaled pathogens. Bacterial constituents ligate Toll-like receptors (TLRs) on AMs, causing AMs to secrete proinflammatory cytokines that activate alveolar epithelial receptors, leading to recruitment of neutrophils that engulf pathogens. Because the AM-induced response could itself cause tissue injury, it is unclear how AMs modulate the response to prevent injury. Here, using real-time alveolar imaging in situ, we show that a subset of AMs attached to the alveolar wall form connexin 43 (Cx43)-containing gap junction channels with the epithelium. During lipopolysaccharide-induced inflammation, the AMs remained sessile and attached to the alveoli, and they established intercommunication through synchronized Ca2+ waves, using the epithelium as the conducting pathway. The intercommunication was immunosuppressive, involving Ca2+-dependent activation of Akt, because AM-specific knockout of Cx43 enhanced alveolar neutrophil recruitment and secretion of proinflammatory cytokines in the bronchoalveolar lavage. A picture emerges of a novel immunomodulatory process in which a subset of alveolus-attached AMs intercommunicates immunosuppressive signals to reduce endotoxin-induced lung inflammation.

Molecular detection of Anaplasma platys, Ehrlichia canis, Hepatozoon canis and Rickettsia monacensis in dogs from Maio Island of Cape Verde archipelago.

PubMed

Lauzi, Stefania; Maia, João P; Epis, Sara; Marcos, Ricardo; Pereira, Cristina; Luzzago, Camilla; Santos, Marta; Puente-Payo, Pablo; Giordano, Alessia; Pajoro, Massimo; Sironi, Giuseppe; Faustino, Augusto

2016-07-01

Tick-borne diseases are emerging worldwide and have an important zoonotic relevance. Dogs play an important role in the epidemiology of several zoonotic tick-borne pathogens acting as sentinels and/or reservoirs. This study focused on the molecular identification of tick-borne pathogens in blood samples of 153 autochthonous asymptomatic dogs in Maio Island, Cape Verde archipelago. Eighty-four (54.9%) dogs were positive for one or more pathogens. Fifty-five (35.9%) dogs were infected with Hepatozoon canis, 53 (34.6%) with Anaplasma platys, five (3.3%) with Ehrlichia canis and Rickettsia monacensis, an emerging human pathogen, was also identified in a single dog (0.7%). The former three pathogens cause important canine tick-borne diseases that are transmitted or potentially transmitted by Rhipicephalus sanguineus s.l., the only hard tick identified in Cape Verde. Furthermore, Wolbachia spp. was amplified from the blood of one dog. None of the dogs were positive for Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Midichloria mitochondrii, Bartonella spp., Babesia spp. or Theileria spp. Fifty-four (35.3%) animals showed single infections and 30 (19.6%) co-infections, with A. platys and H. canis co-infection being the most frequent (28 dogs, 18.3%). The frequency of E. canis infection was statistically different among age groups (P=0.017), being higher among dogs older than 4 years compared to younger dogs. Infection by A. platys was also statistically different among age groups (P=0.031), being higher in dogs younger than 2 years compared to older dogs. The statistical analyses showed no significant association of PCR positivity with gender or location. The frequency of tick-borne pathogens detected in dogs in Maio Island, including R. monacensis, highlights the need to improve diagnosis and control in order to prevent the risk of transmission of these pathogens among dogs and humans living in or travelling to this touristic island. Copyright © 2016 Elsevier GmbH. All rights reserved.

Lethality of First Contact Dysentery Epidemics on Pacific Islands.

PubMed

Shanks, G Dennis

2016-08-03

Infectious diseases depopulated many isolated Pacific islands when they were first exposed to global pathogen circulation from the 18th century. Although the mortality was great, the lack of medical observers makes determination of what happened during these historical epidemics largely speculative. Bacillary dysentery caused by Shigella is the most likely infection causing some of the most lethal island epidemics. The fragmentary historical record is reviewed to gain insight into the possible causes of the extreme lethality that was observed during first-contact epidemics in the Pacific. Immune aspects of the early dysentery epidemics and postmeasles infection resulting in subacute inflammatory enteric disease suggest that epidemiologic isolation was the major lethality risk factor on Pacific islands in the 19th century. Other possible risk factors include human leukocyte antigen homogeneity from a founder effect and pathogen-induced derangement of immune tolerance to gut flora. If this analysis is correct, then Pacific islands are currently at no greater risk of emerging disease epidemics than other developing countries despite their dark history. © The American Society of Tropical Medicine and Hygiene.

An unusual pathogen in ambulatory care: two cases of Scedosporium soft tissue infections presenting as "unresponsive cellulitis".

PubMed

Misselbrook, Gary Peter; Lillie, Patrick; Thomas, Claire P

2016-01-01

Soft tissue infections with Scedosporium spp. are an uncommon but serious and emerging cause of infection in immunocompromised patients. Acute Medical Units (AMUs) in the UK are increasingly managing patients with cellulitis in an outpatient setting, therefore acute physicians should be aware of some of the more uncommon causes of soft tissue infection, particularly in patients not responding to initial antibiotic therapy. We present two cases of Scedosporium presenting to the AMU as cellulitis not responding to initial antibiotic therapy and outline the assessment and management of this important condition.

Neonatal necrotizing fasciitis of the scrotum caused by Streptococcus agalactiae.

PubMed

Kuroda, Junpei; Inoue, Nobuaki; Satoh, Hiroyuki; Fukuzawa, Ryuji; Terakawa, Toshiro; Hasegawa, Yukihiro

2015-04-01

We herein describe the case of a 27-day-old male infant who was brought to the emergency room for intermittent crying, and swelling of the left scrotum. Based on the clinical findings, necrotizing fasciitis was suspected, and surgical intervention was successfully completed within a few hours of admission. Streptococcus agalactiae type Ia was cultured from the drained abscess, and was considered the causative pathogen. To our knowledge, this is the first report of neonatal necrotizing fasciitis caused by S. agalactiae. Prompt diagnosis and immediate surgical debridement are crucial in the initial management of this disease. © 2015 Japan Pediatric Society.

Multidisciplinary approach to epizootiology and pathogenesis of bat rabies viruses in the United States.

PubMed

Ellison, J A; Johnson, S R; Kuzmina, N; Gilbert, A; Carson, W C; VerCauteren, K C; Rupprecht, C E

2013-02-01

Zoonotic disease surveillance is typically initiated after an animal pathogen has caused disease in humans. Early detection of potentially high-risk pathogens within animal hosts may facilitate medical interventions to cope with an emerging disease. To effectively spillover to a novel host, a pathogen may undergo genetic changes resulting in varying transmission potential in the new host and potentially to humans. Rabies virus (RABV) is one model pathogen to consider for studying the dynamics of emerging infectious diseases under both laboratory and field conditions. The evolutionary history of RABV is characterized by regularly documented spillover infections and a series of notable host shifts. Within this context, enhanced field surveillance to improve detection of spillover infections will require validated techniques to non-invasively differentiate infected from non-infected individuals. In this study, we evaluate the use of infrared thermography to detect thermal changes associated with experimental RABV infection in big brown bats (Eptesicus fuscus) in a captive colony. Our results indicated that 62% of rabid bats had detectable facial temperature decreases (-4.6°C, SD ± 2.5) compared with pre-inoculation baseline values. These data suggest potential utility for discriminating rabid bats in natural field settings. In addition, focusing upon RABV circulating in the United States between 2008 and 2011, we confirmed spillover events of bat RABV among carnivores and identified cross-species transmission events caused by four lineages of RABV associated with insectivorous bats. Additionally, our analysis of RABV glycoprotein sequences identified substitutions in antigenic sites that may affect neutralizing activity associated with monoclonal antibodies proposed for use in human post-exposure prophylaxis. This study provides a glimpse into RABV pathobiology and spillover dynamics among and between bats and a variety of mesocarnivores. Published 2012. This article is a US Government work and is in the public domain in the USA.

Importance of clinical microbiologists for U.S. healthcare infrastructure.

PubMed

Carvalho, John

2011-01-01

Clinical microbiologists are highly skilled scientists within national hospitals and reference laboratories who diagnose patients with infections by emerging pathogens. Most advanced training for clinical microbiologists occurs at universities, where an individual can receive certification as a "Medical Laboratory Scientist" (MLS). Unfortunately, many MLS programs have closed in the United States and this has caused a shortage of clinical microbiologists at U.S. hospitals and reference laboratories. This paper explores the present crisis in MLS training and its ramifications for the emergence of antibiotic-resistant bacteria, the economics of hospitals, and the overall health of the nation, and provides resolutions for better public health policy with respect to MLS education.

Role of India's wildlife in the emergence and re-emergence of zoonotic pathogens, risk factors and public health implications.

PubMed

Singh, B B; Gajadhar, A A

2014-10-01

Evolving land use practices have led to an increase in interactions at the human/wildlife interface. The presence and poor knowledge of zoonotic pathogens in India's wildlife and the occurrence of enormous human populations interfacing with, and critically linked to, forest ecosystems warrant attention. Factors such as diverse migratory bird populations, climate change, expanding human population and shrinking wildlife habitats play a significant role in the emergence and re-emergence of zoonotic pathogens from India's wildlife. The introduction of a novel Kyasanur forest disease virus (family flaviviridae) into human populations in 1957 and subsequent occurrence of seasonal outbreaks illustrate the key role that India's wild animals play in the emergence and reemergence of zoonotic pathogens. Other high priority zoonotic diseases of wildlife origin which could affect both livestock and humans include influenza, Nipah, Japanese encephalitis, rabies, plague, leptospirosis, anthrax and leishmaniasis. Continuous monitoring of India's extensively diverse and dispersed wildlife is challenging, but their use as indicators should facilitate efficient and rapid disease-outbreak response across the region and occasionally the globe. Defining and prioritizing research on zoonotic pathogens in wildlife are essential, particularly in a multidisciplinary one-world one-health approach which includes human and veterinary medical studies at the wildlife-livestock-human interfaces. This review indicates that wild animals play an important role in the emergence and re-emergence of zoonotic pathogens and provides brief summaries of the zoonotic diseases that have occurred in wild animals in India. Copyright © 2014 Elsevier B.V. All rights reserved.

Phylogenetic analysis reveals two genotypes of the emerging fungus Mucor indicus, an opportunistic human pathogen in immunocompromised patients.

PubMed

Taj-Aldeen, Saad J; Almaslamani, Muna; Theelen, Bart; Boekhout, Teun

2017-07-12

Mucormycosis is a rare fungal infection caused by Mucor indicus. Phylogenetic analysis of many M. indicus isolates, mainly sampled from different clinical and environmental specimens collected worldwide, revealed two genotypes, I and II, based on ITS and D1/D2 LSU rDNA sequences. A retrospective review of the literature revealed 13 cases. Eight (76.9%) patients had disseminated infections, and the overall mortality rate was 30.7%. A pulmonary infection caused by M. indicus genotype I in a liver transplant recipient was disseminated to include the skin and was successfully treated with liposomal amphotericin B and aggressive surgery. M. indicus can infect a wide variety of patients with no real preference for the site of infection. We concluded that M. indicus has emerged as a significant cause of invasive mycosis in severely immunocompromised patients worldwide. Early diagnosis and initiation of appropriate therapy could enhance survival in these immunocompromised patient populations.

Recent human-to-poultry host jump, adaptation, and pandemic spread of Staphylococcus aureus.

PubMed

Lowder, Bethan V; Guinane, Caitriona M; Ben Zakour, Nouri L; Weinert, Lucy A; Conway-Morris, Andrew; Cartwright, Robyn A; Simpson, A John; Rambaut, Andrew; Nübel, Ulrich; Fitzgerald, J Ross

2009-11-17

The impact of globalization on the emergence and spread of pathogens is an important veterinary and public health issue. Staphylococcus aureus is a notorious human pathogen associated with serious nosocomial and community-acquired infections. In addition, S. aureus is a major cause of animal diseases including skeletal infections of poultry, which are a large economic burden on the global broiler chicken industry. Here, we provide evidence that the majority of S. aureus isolates from broiler chickens are the descendants of a single human-to-poultry host jump that occurred approximately 38 years ago (range, 30 to 63 years ago) by a subtype of the worldwide human ST5 clonal lineage unique to Poland. In contrast to human subtypes of the ST5 radiation, which demonstrate strong geographic clustering, the poultry ST5 clade was distributed in different continents, consistent with wide dissemination via the global poultry industry distribution network. The poultry ST5 clade has undergone genetic diversification from its human progenitor strain by acquisition of novel mobile genetic elements from an avian-specific accessory gene pool, and by the inactivation of several proteins important for human disease pathogenesis. These genetic events have resulted in enhanced resistance to killing by chicken heterophils, reflecting avian host-adaptive evolution. Taken together, we have determined the evolutionary history of a major new animal pathogen that has undergone rapid avian host adaptation and intercontinental dissemination. These data provide a new paradigm for the impact of human activities on the emergence of animal pathogens.

Insights into the Emergent Bacterial Pathogen Cronobacter spp., Generated by Multilocus Sequence Typing and Analysis

PubMed Central

Joseph, Susan; Forsythe, Stephen J.

2012-01-01

Cronobacter spp. (previously known as Enterobacter sakazakii) is a bacterial pathogen affecting all age groups, with particularly severe clinical complications in neonates and infants. One recognized route of infection being the consumption of contaminated infant formula. As a recently recognized bacterial pathogen of considerable importance and regulatory control, appropriate detection, and identification schemes are required. The application of multilocus sequence typing (MLST) and analysis (MLSA) of the seven alleles atpD, fusA, glnS, gltB, gyrB, infB, and ppsA (concatenated length 3036 base pairs) has led to considerable advances in our understanding of the genus. This approach is supported by both the reliability of DNA sequencing over subjective phenotyping and the establishment of a MLST database which has open access and is also curated; http://www.pubMLST.org/cronobacter. MLST has been used to describe the diversity of the newly recognized genus, instrumental in the formal recognition of new Cronobacter species (C. universalis and C. condimenti) and revealed the high clonality of strains and the association of clonal complex 4 with neonatal meningitis cases. Clearly the MLST approach has considerable benefits over the use of non-DNA sequence based methods of analysis for newly emergent bacterial pathogens. The application of MLST and MLSA has dramatically enabled us to better understand this opportunistic bacterium which can cause irreparable damage to a newborn baby’s brain, and has contributed to improved control measures to protect neonatal health. PMID:23189075

Pathogenic lineage of Perkinsea associated with mass mortality of frogs across the United States

USGS Publications Warehouse

Isidoro Ayza, Marcos; Lorch, Jeffrey M.; Grear, Daniel A.; Winzeler, Megan; Calhoun, Daniel L.; Barichivich, William J.

2017-01-01

Emerging infectious diseases such as chytridiomycosis and ranavirus infections are important contributors to the worldwide decline of amphibian populations. We reviewed data on 247 anuran mortality events in 43 States of the United States from 1999–2015. Our findings suggest that a severe infectious disease of tadpoles caused by a protist belonging to the phylum Perkinsea might represent the third most common infectious disease of anurans after ranavirus infections and chytridiomycosis. Severe Perkinsea infections (SPI) were systemic and led to multiorganic failure and death. The SPI mortality events affected numerous anuran species and occurred over a broad geographic area, from boreal to subtropical habitats. Livers from all PCR-tested SPI-tadpoles (n = 19) were positive for the Novel Alveolate Group 01 (NAG01) of Perkinsea, while only 2.5% histologically normal tadpole livers tested positive (2/81), suggesting that subclinical infections are uncommon. Phylogenetic analysis demonstrated that SPI is associated with a phylogenetically distinct clade of NAG01 Perkinsea. These data suggest that this virulent Perkinsea clade is an important pathogen of frogs in the United States. Given its association with mortality events and tendency to be overlooked, the potential role of this emerging pathogen in amphibian declines on a broad geographic scale warrants further investigation.

Insects as alternative hosts for phytopathogenic bacteria.

PubMed

Nadarasah, Geetanchaly; Stavrinides, John

2011-05-01

Phytopathogens have evolved specialized pathogenicity determinants that enable them to colonize their specific plant hosts and cause disease, but their intimate associations with plants also predispose them to frequent encounters with herbivorous insects, providing these phytopathogens with ample opportunity to colonize and eventually evolve alternative associations with insects. Decades of research have revealed that these associations have resulted in the formation of bacterial-vector relationships, in which the insect mediates dissemination of the plant pathogen. Emerging research, however, has highlighted the ability of plant pathogenic bacteria to use insects as alternative hosts, exploiting them as they would their primary plant host. The identification of specific bacterial genetic determinants that mediate the interaction between bacterium and insect suggests that these interactions are not incidental, but have likely arisen following the repeated association of microorganisms with particular insects over evolutionary time. This review will address the biology and ecology of phytopathogenic bacteria that interact with insects, including the traditional role of insects as vectors, as well as the newly emerging paradigm of insects serving as alternative primary hosts. Also discussed is one case where an insect serves as both host and vector, which may represent a transitionary stage in the evolution of insect-phytopathogen associations. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Human Streptococcus agalactiae strains in aquatic mammals and fish

PubMed Central

2013-01-01

Background In humans, Streptococcus agalactiae or group B streptococcus (GBS) is a frequent coloniser of the rectovaginal tract, a major cause of neonatal infectious disease and an emerging cause of disease in non-pregnant adults. In addition, Streptococcus agalactiae causes invasive disease in fish, compromising food security and posing a zoonotic hazard. We studied the molecular epidemiology of S. agalactiae in fish and other aquatic species to assess potential for pathogen transmission between aquatic species and humans. Methods Isolates from fish (n = 26), seals (n = 6), a dolphin and a frog were characterized by pulsed-field gel electrophoresis, multilocus sequence typing and standardized 3-set genotyping, i.e. molecular serotyping and profiling of surface protein genes and mobile genetic elements. Results Four subpopulations of S. agalactiae were identified among aquatic isolates. Sequence type (ST) 283 serotype III-4 and its novel single locus variant ST491 were detected in fish from Southeast Asia and shared a 3-set genotype identical to that of an emerging ST283 clone associated with invasive disease of adult humans in Asia. The human pathogenic strain ST7 serotype Ia was also detected in fish from Asia. ST23 serotype Ia, a subpopulation that is normally associated with human carriage, was found in all grey seals, suggesting that human effluent may contribute to microbial pollution of surface water and exposure of sea mammals to human pathogens. The final subpopulation consisted of non-haemolytic ST260 and ST261 serotype Ib isolates, which belong to a fish-associated clonal complex that has never been reported from humans. Conclusions The apparent association of the four subpopulations of S. agalactiae with specific groups of host species suggests that some strains of aquatic S. agalactiae may present a zoonotic or anthroponotic hazard. Furthermore, it provides a rational framework for exploration of pathogenesis and host-associated genome content of S. agalactiae strains. PMID:23419028

The flagellar master operon flhDC is a pleiotropic regulator involved in motility and virulence of the fish pathogen Yersinia ruckeri.

PubMed

Jozwick, A K S; Graf, J; Welch, T J

2017-03-01

To investigate the function of the master flagellar operon flhDC in the fish pathogen Yersinia ruckeri and compare the effect of a constructed flhD mutation to a naturally occurring fliR mutation causing loss-of-motility in emergent biotype 2 (BT2) strains. Yersinia ruckeri flhD and fliR mutants were constructed in a motile strain. Both mutations caused loss-of-motility, ablation of flagellin synthesis and phospholipase secretion, similar to naturally occurring BT2 strains. Transcriptome analysis confirmed flhDC regulation of flagellar, chemotaxis and phospholipase loci as well as other genes of diverse function. The flhD mutation confers a competitive advantage within the fish host when compared with its parent strain, while this advantage was not seen with the naturally occurring fliR mutation. An intact flhD is necessary for expression of the flagellar secretion system as well as other diverse loci, consistent with a role for flhD as a pleiotropic regulator. The maintenance of the flhD locus in Y. ruckeri strains suggests its importance for aspects of Y. ruckeri biology other than virulence, since the flhD mutation conferred a competitive advantage during experimental challenge of rainbow trout. Yersinia ruckeri is the causative agent of enteric red mouth disease, an invasive septicaemia that affects farmed salmonid fish species. Disease outbreaks can cause severe economic losses in aquaculture. BT2 variants, which have independently emerged worldwide, are an increasing threat to farmed fish production. Knowledge of mechanisms involved in virulence, conserved functions and gene regulation among strains may be exploited for the development of novel disease control strategies to prevent pathogen growth or virulence phenotypes within aquaculture. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Network Analysis Highlights Complex Interactions between Pathogen, Host and Commensal Microbiota

PubMed Central

Boutin, Sébastien; Bernatchez, Louis; Audet, Céline; Derôme, Nicolas

2013-01-01

Interactions between bacteria and their host represent a full continuum from pathogenicity to mutualism. From an evolutionary perspective, host-bacteria relationships are no longer considered a two-component system but rather a complex network. In this study, we focused on the relationship between brook charr (Salvelinus fontinalis) and bacterial communities developing on skin mucus. We hypothesized that stressful conditions such as those occurring in aquaculture production induce shifts in the bacterial community of healthy fish, thus allowing pathogens to cause infections. The results showed that fish skin mucus microbiota taxonomical structure is highly specific, its diversity being partly influenced by the surrounding water bacterial community. Two types of taxonomic co-variation patterns emerged across 121 contrasted communities’ samples: one encompassing four genera well known for their probiotic properties, the other harboring five genera mostly associated with pathogen species. The homeostasis of fish bacterial community was extensively disturbed by induction of physiological stress in that both: 1) the abundance of probiotic-like bacteria decreased after stress exposure; and 2) pathogenic bacteria increased following stress exposure. This study provides further insights regarding the role of mutualistic bacteria as a primary host protection barrier. PMID:24376845

Development of an aquatic pathogen database (AquaPathogen X) and its utilization in tracking emerging fish virus pathogens in North America

USGS Publications Warehouse

Emmenegger, E.J.; Kentop, E.; Thompson, T.M.; Pittam, S.; Ryan, A.; Keon, D.; Carlino, J.A.; Ranson, J.; Life, R.B.; Troyer, R.M.; Garver, K.A.; Kurath, G.

2011-01-01

The AquaPathogen X database is a template for recording information on individual isolates of aquatic pathogens and is freely available for download (http://wfrc.usgs.gov). This database can accommodate the nucleotide sequence data generated in molecular epidemiological studies along with the myriad of abiotic and biotic traits associated with isolates of various pathogens (e.g. viruses, parasites and bacteria) from multiple aquatic animal host species (e.g. fish, shellfish and shrimp). The cataloguing of isolates from different aquatic pathogens simultaneously is a unique feature to the AquaPathogen X database, which can be used in surveillance of emerging aquatic animal diseases and elucidation of key risk factors associated with pathogen incursions into new water systems. An application of the template database that stores the epidemiological profiles of fish virus isolates, called Fish ViroTrak, was also developed. Exported records for two aquatic rhabdovirus species emerging in North America were used in the implementation of two separate web-accessible databases: the Molecular Epidemiology of Aquatic Pathogens infectious haematopoietic necrosis virus (MEAP-IHNV) database (http://gis.nacse.org/ihnv/) released in 2006 and the MEAP- viral haemorrhagic septicaemia virus (http://gis.nacse.org/vhsv/) database released in 2010.

Abelson Kinase Inhibitors Are Potent Inhibitors of Severe Acute Respiratory Syndrome Coronavirus and Middle East Respiratory Syndrome Coronavirus Fusion

PubMed Central

Coleman, Christopher M.; Sisk, Jeanne M.; Mingo, Rebecca M.; Nelson, Elizabeth A.; White, Judith M.

2016-01-01

ABSTRACT The highly pathogenic severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) cause significant morbidity and morality. There is currently no approved therapeutic for highly pathogenic coronaviruses, even as MERS-CoV is spreading throughout the Middle East. We previously screened a library of FDA-approved drugs for inhibitors of coronavirus replication in which we identified Abelson (Abl) kinase inhibitors, including the anticancer drug imatinib, as inhibitors of both SARS-CoV and MERS-CoV in vitro. Here we show that the anti-CoV activity of imatinib occurs at the early stages of infection, after internalization and endosomal trafficking, by inhibiting fusion of the virions at the endosomal membrane. We specifically identified the imatinib target, Abelson tyrosine-protein kinase 2 (Abl2), as required for efficient SARS-CoV and MERS-CoV replication in vitro. These data demonstrate that specific approved drugs can be characterized in vitro for their anticoronavirus activity and used to identify host proteins required for coronavirus replication. This type of study is an important step in the repurposing of approved drugs for treatment of emerging coronaviruses. IMPORTANCE Both SARS-CoV and MERS-CoV are zoonotic infections, with bats as the primary source. The 2003 SARS-CoV outbreak began in Guangdong Province in China and spread to humans via civet cats and raccoon dogs in the wet markets before spreading to 37 countries. The virus caused 8,096 confirmed cases of SARS and 774 deaths (a case fatality rate of ∼10%). The MERS-CoV outbreak began in Saudi Arabia and has spread to 27 countries. MERS-CoV is believed to have emerged from bats and passed into humans via camels. The ongoing outbreak of MERS-CoV has resulted in 1,791 cases of MERS and 640 deaths (a case fatality rate of 36%). The emergence of SARS-CoV and MERS-CoV provides evidence that coronaviruses are currently spreading from zoonotic sources and can be highly pathogenic, causing serious morbidity and mortality in humans. Treatment of SARS-CoV and MERS-CoV infection is limited to providing supportive therapy consistent with any serious lung disease, as no specific drugs have been approved as therapeutics. Highly pathogenic coronaviruses are rare and appear to emerge and disappear within just a few years. Currently, MERS-CoV is still spreading, as new infections continue to be reported. The outbreaks of SARS-CoV and MERS-CoV and the continuing diagnosis of new MERS cases highlight the need for finding therapeutics for these diseases and potential future coronavirus outbreaks. Screening FDA-approved drugs streamlines the pipeline for this process, as these drugs have already been tested for safety in humans. PMID:27466418

Sequence type 1 group B Streptococcus, an emerging cause of invasive disease in adults, evolves by small genetic changes

PubMed Central

Flores, Anthony R.; Galloway-Peña, Jessica; Sahasrabhojane, Pranoti; Saldaña, Miguel; Yao, Hui; Su, Xiaoping; Ajami, Nadim J.; Holder, Michael E.; Petrosino, Joseph F.; Thompson, Erika; Margarit Y Ros, Immaculada; Rosini, Roberto; Grandi, Guido; Horstmann, Nicola; Teatero, Sarah; McGeer, Allison; Fittipaldi, Nahuel; Rappuoli, Rino; Baker, Carol J.; Shelburne, Samuel A.

2015-01-01

The molecular mechanisms underlying pathogen emergence in humans is a critical but poorly understood area of microbiologic investigation. Serotype V group B Streptococcus (GBS) was first isolated from humans in 1975, and rates of invasive serotype V GBS disease significantly increased starting in the early 1990s. We found that 210 of 229 serotype V GBS strains (92%) isolated from the bloodstream of nonpregnant adults in the United States and Canada between 1992 and 2013 were multilocus sequence type (ST) 1. Elucidation of the complete genome of a 1992 ST-1 strain revealed that this strain had the highest homology with a GBS strain causing cow mastitis and that the 1992 ST-1 strain differed from serotype V strains isolated in the late 1970s by acquisition of cell surface proteins and antimicrobial resistance determinants. Whole-genome comparison of 202 invasive ST-1 strains detected significant recombination in only eight strains. The remaining 194 strains differed by an average of 97 SNPs. Phylogenetic analysis revealed a temporally dependent mode of genetic diversification consistent with the emergence in the 1990s of ST-1 GBS as major agents of human disease. Thirty-one loci were identified as being under positive selective pressure, and mutations at loci encoding polysaccharide capsule production proteins, regulators of pilus expression, and two-component gene regulatory systems were shown to affect the bacterial phenotype. These data reveal that phenotypic diversity among ST-1 GBS is mainly driven by small genetic changes rather than extensive recombination, thereby extending knowledge into how pathogens adapt to humans. PMID:25941374

Sequence type 1 group B Streptococcus, an emerging cause of invasive disease in adults, evolves by small genetic changes.

PubMed

Flores, Anthony R; Galloway-Peña, Jessica; Sahasrabhojane, Pranoti; Saldaña, Miguel; Yao, Hui; Su, Xiaoping; Ajami, Nadim J; Holder, Michael E; Petrosino, Joseph F; Thompson, Erika; Margarit Y Ros, Immaculada; Rosini, Roberto; Grandi, Guido; Horstmann, Nicola; Teatero, Sarah; McGeer, Allison; Fittipaldi, Nahuel; Rappuoli, Rino; Baker, Carol J; Shelburne, Samuel A

2015-05-19

The molecular mechanisms underlying pathogen emergence in humans is a critical but poorly understood area of microbiologic investigation. Serotype V group B Streptococcus (GBS) was first isolated from humans in 1975, and rates of invasive serotype V GBS disease significantly increased starting in the early 1990s. We found that 210 of 229 serotype V GBS strains (92%) isolated from the bloodstream of nonpregnant adults in the United States and Canada between 1992 and 2013 were multilocus sequence type (ST) 1. Elucidation of the complete genome of a 1992 ST-1 strain revealed that this strain had the highest homology with a GBS strain causing cow mastitis and that the 1992 ST-1 strain differed from serotype V strains isolated in the late 1970s by acquisition of cell surface proteins and antimicrobial resistance determinants. Whole-genome comparison of 202 invasive ST-1 strains detected significant recombination in only eight strains. The remaining 194 strains differed by an average of 97 SNPs. Phylogenetic analysis revealed a temporally dependent mode of genetic diversification consistent with the emergence in the 1990s of ST-1 GBS as major agents of human disease. Thirty-one loci were identified as being under positive selective pressure, and mutations at loci encoding polysaccharide capsule production proteins, regulators of pilus expression, and two-component gene regulatory systems were shown to affect the bacterial phenotype. These data reveal that phenotypic diversity among ST-1 GBS is mainly driven by small genetic changes rather than extensive recombination, thereby extending knowledge into how pathogens adapt to humans.

Global food and fibre security threatened by current inefficiencies in fungal identification.

PubMed

Crous, Pedro W; Groenewald, Johannes Z; Slippers, Bernard; Wingfield, Michael J

2016-12-05

Fungal pathogens severely impact global food and fibre crop security. Fungal species that cause plant diseases have mostly been recognized based on their morphology. In general, morphological descriptions remain disconnected from crucially important knowledge such as mating types, host specificity, life cycle stages and population structures. The majority of current fungal species descriptions lack even the most basic genetic data that could address at least some of these issues. Such information is essential for accurate fungal identifications, to link critical metadata and to understand the real and potential impact of fungal pathogens on production and natural ecosystems. Because international trade in plant products and introduction of pathogens to new areas is likely to continue, the manner in which fungal pathogens are identified should urgently be reconsidered. The technologies that would provide appropriate information for biosecurity and quarantine already exist, yet the scientific community and the regulatory authorities are slow to embrace them. International agreements are urgently needed to enforce new guidelines for describing plant pathogenic fungi (including key DNA information), to ensure availability of relevant data and to modernize the phytosanitary systems that must deal with the risks relating to trade-associated plant pathogens.This article is part of the themed issue 'Tackling emerging fungal threats to animal health, food security and ecosystem resilience'. © 2016 The Author(s).

Perspectives on emerging zoonotic disease research and capacity building in Canada

PubMed Central

Stephen, Craig; Artsob, Harvey; Bowie, William R; Drebot, Michael; Fraser, Erin; Leighton, Ted; Morshed, Muhammad; Ong, Corinne; Patrick, David

2004-01-01

Zoonoses are fundamental determinants of community health. Preventing, identifying and managing these infections must be a central public health focus. Most current zoonoses research focuses on the interface of the pathogen and the clinically ill person, emphasizing microbial detection, mechanisms of pathogenicity and clinical intervention strategies, rather than examining the causes of emergence, persistence and spread of new zoonoses. There are gaps in the understanding of the animal determinants of emergence and the capacity to train highly qualified individuals; these are major obstacles to preventing new disease threats. The ability to predict the emergence of zoonoses and their resulting public health and societal impacts are hindered when insufficient effort is devoted to understanding zoonotic disease epidemiology, and when zoonoses are not examined in a manner that yields fundamental insight into their origin and spread. Emerging infectious disease research should rest on four pillars: enhanced communications across disciplinary and agency boundaries; the assessment and development of surveillance and disease detection tools; the examination of linkages between animal health determinants of human health outcomes; and finally, cross-disciplinary training and research. A national strategy to predict, prevent and manage emerging diseases must have a prominent and explicit role for veterinary and biological researchers. An integrated health approach would provide decision makers with a firmer foundation from which to build evidence-based disease prevention and control plans that involve complex human/animal/environmental systems, and would serve as the foundation to train and support the new cadre of individuals ultimately needed to maintain and apply research capacity in this area. PMID:18159512

Perspectives on emerging zoonotic disease research and capacity building in Canada.

PubMed Central

Stephen, Craig; Artsob, Harvey; Bowie, William R.; Drebot, Michael; Fraser, Erin; Leighton, Ted; Morshed, Muhammad; Ong, Corinne; Patrick, David

2005-01-01

Zoonoses are fundamental determinants of community health. Preventing, identifying and managing these infections must be a central public health focus. Most current zoonoses research focuses on the interface of the pathogen and the clinically ill person, emphasizing microbial detection, mechanisms of pathogenicity and clinical intervention strategies, rather than examining the causes of emergence, persistence and spread of new zoonoses. There are gaps in the understanding of the animal determinants of emergence and the capacity to train highly qualified individuals; these are major obstacles to preventing new disease threats. The ability to predict the emergence of zoonoses and their resulting public health and societal impacts are hindered when insufficient effort is devoted to understanding zoonotic disease epidemiology, and when zoonoses are not examined in a manner that yields fundamental insight into their origin and spread. Emerging infectious disease research should rest on four pillars: enhanced communications across disciplinary and agency boundaries; the assessment and development of surveillance and disease detection tools; the examination of linkages between animal health determinants of human health outcomes; and finally, cross-disciplinary training and research. A national strategy to predict, prevent and manage emerging diseases must have a prominent and explicit role for veterinary and biological researchers. An integrated health approach would provide decision makers with a firmer foundation from which to build evidence-based disease prevention and control plans that involve complex human/animal/environmental systems, and would serve as the foundation to train and support the new cadre of individuals ultimately needed to maintain and apply research capacity in this area. PMID:15759832

A pivotal role for the Streptococcus iniae extracellular polysaccharide in triggering proinflammatory cytokines transcription and inducing death in rainbow trout.

PubMed

Eyngor, Marina; Lublin, Avishay; Shapira, Roni; Hurvitz, Avshalom; Zlotkin, Amir; Tekoah, Yoram; Eldar, Avi

2010-04-01

Streptococcus iniae is a major pathogen of fish, causing considerable economic losses in Israel, the United States and the Far East. Containment of mortalities through vaccination was recently compromised due to the emergence of novel vaccine-escape strains that are distinguished from previous strains by their ability to produce large amounts of extracellular polysaccharide (EPS) that is released to the medium. In vitro and in vivo data now indicate that the EPS is a major virulence factor, capable of triggering the proinflammatory cytokine machinery and inducing mortality of fish. Streptococcus iniae EPS might therefore be considered to be responsible for sepsis and death just as lipopolysaccharide is for Gram-negative pathogens.

β-lactam resistance in gram-negative pathogens isolated from animals.

PubMed

Trott, Darren

2013-01-01

Although β-lactams remain a cornerstone of veterinary therapeutics, only a restricted number are actually approved for use in food-producing livestock in comparison to companion animals and wildlife. Nevertheless, both registered and off-label use of third and fourth-generation cephalosporins in livestock may have influenced the emergence of plasmid-encoded AmpC β-lactamases (pAmpC) (mainly CMY-2) and CTX-M extended-spectrum β-lactamases (ESBLs) in both Gram-negative pathogens and commensals isolated from animals. This presents a public health concern due to the potential risk of transfer of β-lactam-resistant pathogens from livestock to humans through food. The recent detection of pAmpC and ESBLs in multidrug-resistant Enterobacteriaceae isolated from dogs has also confirmed the public health importance of β-lactam resistance in companion animals, though in this case, human-to-animal transmission may be equally as relevant as animal-to-human transmission. Identification of pAmpC and ESBLs in Enterobacteriaceae isolated from wildlife and aquaculture species may be evidence of environmental selection pressure arising from both human and veterinary use of β- lactams. Such selection pressure in animals could be reduced by the availability of reliable alternative control measures such as vaccines, bacteriophage treatments and/or competitive exclusion models for endemic production animal diseases such as colibacillosis. The global emergence and pandemic spread of extraintestinal pathogenic E. coli O25-ST131 strains expressing CTX-M-15 ESBL in humans and its recent detection in livestock, companion animals and wildlife is a major cause for concern and goes against the paradigm that Gramnegative pathogens do not necessarily have to lose virulence in compensation for acquiring resistance.

Selected Pathogens of Concern to Industrial Food Processors: Infectious, Toxigenic, Toxico-Infectious, Selected Emerging Pathogenic Bacteria

NASA Astrophysics Data System (ADS)

Behling, Robert G.; Eifert, Joseph; Erickson, Marilyn C.; Gurtler, Joshua B.; Kornacki, Jeffrey L.; Line, Erick; Radcliff, Roy; Ryser, Elliot T.; Stawick, Bradley; Yan, Zhinong

This chapter, written by several contributing authors, is devoted to discussing selected microbes of contemporary importance. Microbes from three categories are described by the following: (1) infectious invasive agents like Salmonella, Listeria monocytogenes, and Campylobacter; (2) toxigenic pathogens such as Staphylococcus aureus, Bacillus cereus, and Clostridium botulinum; and (3) toxico-infectious agents like enterohemorrhagic Escherichia coli and Clostridium perfringens. In addition, emerging pathogens, like Cronobacter (Enterobacter) sakazakii, Arcobacter spp., and Mycobacterium avium subspecies paratuberculosis are also described.

Variations in Virulence and Molecular Biology among Emerging Strains of Clostridium difficile

PubMed Central

Hunt, Jonathan J.

2013-01-01

SUMMARY Clostridium difficile is a Gram-positive, spore-forming organism which infects and colonizes the large intestine, produces potent toxins, triggers inflammation, and causes significant systemic complications. Treating C. difficile infection (CDI) has always been difficult, because the disease is both caused and resolved by antibiotic treatment. For three and a half decades, C. difficile has presented a treatment challenge to clinicians, and the situation took a turn for the worse about 10 years ago. An increase in epidemic outbreaks related to CDI was first noticed around 2003, and these outbreaks correlated with a sudden increase in the mortality rate of this illness. Further studies discovered that these changes in CDI epidemiology were associated with the rapid emergence of hypervirulent strains of C. difficile, now collectively referred to as NAP1/BI/027 strains. The discovery of new epidemic strains of C. difficile has provided a unique opportunity for retrospective and prospective studies that have sought to understand how these strains have essentially replaced more historical strains as a major cause of CDI. Moreover, detailed studies on the pathogenesis of NAP1/BI/027 strains are leading to new hypotheses on how this emerging strain causes severe disease and is more commonly associated with epidemics. In this review, we provide an overview of CDI, discuss critical mechanisms of C. difficile virulence, and explain how differences in virulence-associated factors between historical and newly emerging strains might explain the hypervirulence exhibited by this pathogen during the past decade. PMID:24296572

Diagnosis, Treatment, and Prevention of Hemodialysis Emergencies.

PubMed

Saha, Manish; Allon, Michael

2017-02-07

Given the high comorbidity in patients on hemodialysis and the complexity of the dialysis treatment, it is remarkable how rarely a life-threatening complication occurs during dialysis. The low rate of dialysis emergencies can be attributed to numerous safety features in modern dialysis machines; meticulous treatment and testing of the dialysate solution to prevent exposure to trace elements, toxins, and pathogens; adherence to detailed treatment protocols; and extensive training of dialysis staff to handle medical emergencies. Most hemodialysis emergencies can be attributed to human error. A smaller number are due to rare idiosyncratic reactions. In this review, we highlight major emergencies that may occur during hemodialysis treatments, describe their pathogenesis, offer measures to minimize them, and provide specific interventions to prevent catastrophic consequences on the rare occasions when such emergencies arise. These emergencies include dialysis disequilibrium syndrome, venous air embolism, hemolysis, venous needle dislodgement, vascular access hemorrhage, major allergic reactions to the dialyzer or treatment medications, and disruption or contamination of the dialysis water system. Finally, we describe root cause analysis after a dialysis emergency has occurred to prevent a future recurrence. Copyright © 2017 by the American Society of Nephrology.

Diagnosis, Treatment, and Prevention of Hemodialysis Emergencies

PubMed Central

Saha, Manish

2017-01-01

Given the high comorbidity in patients on hemodialysis and the complexity of the dialysis treatment, it is remarkable how rarely a life-threatening complication occurs during dialysis. The low rate of dialysis emergencies can be attributed to numerous safety features in modern dialysis machines; meticulous treatment and testing of the dialysate solution to prevent exposure to trace elements, toxins, and pathogens; adherence to detailed treatment protocols; and extensive training of dialysis staff to handle medical emergencies. Most hemodialysis emergencies can be attributed to human error. A smaller number are due to rare idiosyncratic reactions. In this review, we highlight major emergencies that may occur during hemodialysis treatments, describe their pathogenesis, offer measures to minimize them, and provide specific interventions to prevent catastrophic consequences on the rare occasions when such emergencies arise. These emergencies include dialysis disequilibrium syndrome, venous air embolism, hemolysis, venous needle dislodgement, vascular access hemorrhage, major allergic reactions to the dialyzer or treatment medications, and disruption or contamination of the dialysis water system. Finally, we describe root cause analysis after a dialysis emergency has occurred to prevent a future recurrence. PMID:27831511

Massively multiplexed microbial identification using resequencing DNA microarrays for outbreak investigation

NASA Astrophysics Data System (ADS)

Leski, T. A.; Ansumana, R.; Jimmy, D. H.; Bangura, U.; Malanoski, A. P.; Lin, B.; Stenger, D. A.

2011-06-01

Multiplexed microbial diagnostic assays are a promising method for detection and identification of pathogens causing syndromes characterized by nonspecific symptoms in which traditional differential diagnosis is difficult. Also such assays can play an important role in outbreak investigations and environmental screening for intentional or accidental release of biothreat agents, which requires simultaneous testing for hundreds of potential pathogens. The resequencing pathogen microarray (RPM) is an emerging technological platform, relying on a combination of massively multiplex PCR and high-density DNA microarrays for rapid detection and high-resolution identification of hundreds of infectious agents simultaneously. The RPM diagnostic system was deployed in Sierra Leone, West Africa in collaboration with Njala University and Mercy Hospital Research Laboratory located in Bo. We used the RPM-Flu microarray designed for broad-range detection of human respiratory pathogens, to investigate a suspected outbreak of avian influenza in a number of poultry farms in which significant mortality of chickens was observed. The microarray results were additionally confirmed by influenza specific real-time PCR. The results of the study excluded the possibility that the outbreak was caused by influenza, but implicated Klebsiella pneumoniae as a possible pathogen. The outcome of this feasibility study confirms that application of broad-spectrum detection platforms for outbreak investigation in low-resource locations is possible and allows for rapid discovery of the responsible agents, even in cases when different agents are suspected. This strategy enables quick and cost effective detection of low probability events such as outbreak of a rare disease or intentional release of a biothreat agent.

The effect of immunodeficiency on the evolution of virulence: an experimental test with the rodent malaria Plasmodium chabaudi.

PubMed

Barclay, Victoria C; Kennedy, David A; Weaver, Veronika C; Sim, Derek; Lloyd-Smith, James O; Read, Andrew F

2014-08-01

Host immunity plays an important role in the evolution of pathogen virulence and disease emergence. There is increasing theoretical and empirical evidence that enhanced immunity through vaccination may have the unfortunate side effect of selecting for more virulent parasites, but the effect of host immune suppression on pathogen evolution is less clear. Here, we use serial passage experiments in mice to test how immune-suppressed hosts may alter pathogen virulence evolution. We passaged Plasmodium chabaudi through CD4(+) T cell-depleted or control mice every 7 days for 20 weeks and then measured virulence differences during infection of immunologically normal mice. We found that those parasites that had been selected through CD4(+) T cell-depleted mice were more virulent than parasites selected through control mice. Virulence increases during serial passage are believed to be caused by pathogen adaptation to the passage host. These data suggest that immune-suppressed hosts could provide a within-host environment that lowers the barrier to parasite adaptation and promotes the evolution of virulence.

Museums and disease: using tissue archive and museum samples to study pathogens.

PubMed

Tsangaras, Kyriakos; Greenwood, Alex D

2012-01-20

Molecular studies of archival and fossil samples have traditionally focused on the nucleic acids derived from the host species. However, there has recently been an increase in ancient DNA research on the identification and characterization of infectious agents within the hosts. The study of pathogens from the past provides great opportunities for discovering the causes of historical infection events, characterizing host-microorganism co-evolution and directly investigating the evolution of specific pathogens. Several research teams have been able to isolate and characterize a variety of different bacterial, parasite and viral microorganisms. However, this emerging field is not without obstacles. The diagenetic processes that make ancient DNA research generally difficult are also impediments to ancient pathogen research and perhaps more so given that their DNA may represent an even rarer proportion of the remaining nucleic acids in a fossil sample than host DNA. However, studies performed under controlled conditions and following stringent ancient DNA protocols can and have yielded reliable and often surprising results. This article reviews the advantages, problems, and failures of ancient microbiological research. Copyright © 2011 Elsevier GmbH. All rights reserved.

Profiling a killer, the development of Cryptococcus neoformans

PubMed Central

Kozubowski, Lukasz; Heitman, Joseph

2012-01-01

The ability of fungi to transition between unicellular and multicellular growth has a profound impact on our health and the economy. Many important fungal pathogens of humans, animals, and plants are dimorphic, and the ability to switch between morphological states has been associated with their virulence. Cryptococcus neoformans is a human fungal pathogen that causes life-threatening meningoencephalitis in immunocompromised and, in some cases, immunocompetent hosts. Cryptococcus neoformans grows vegetatively as a budding yeast and switches to hyphal growth during the sexual cycle, which is important in the study of cryptococcal pathogenicity because spores resulting from sexual development are infectious propagules and can colonize the lungs of a host. In addition, sexual reproduction contributes to the genotypic variability of Cryptococcus species, which may lead to increased fitness and virulence. Despite significant advances in our understanding of the mechanisms behind the development of C. neoformans, our knowledge is still incomplete. Recent studies have led to the emergence of many intriguing questions and hypotheses. In this review, we describe and discuss the most interesting aspects of C. neoformans development and address their impact on pathogenicity. PMID:21658085

Bacterial size matters: Multiple mechanisms controlling septum cleavage and diplococcus formation are critical for the virulence of the opportunistic pathogen Enterococcus faecalis

PubMed Central

Salamaga, Bartłomiej; Prajsnar, Tomasz K.; Willemse, Joost; Bewley, Martin A.; Chau, Françoise

2017-01-01

Enterococcus faecalis is an opportunistic pathogen frequently isolated in clinical settings. This organism is intrinsically resistant to several clinically relevant antibiotics and can transfer resistance to other pathogens. Although E. faecalis has emerged as a major nosocomial pathogen, the mechanisms underlying the virulence of this organism remain elusive. We studied the regulation of daughter cell separation during growth and explored the impact of this process on pathogenesis. We demonstrate that the activity of the AtlA peptidoglycan hydrolase, an enzyme dedicated to septum cleavage, is controlled by several mechanisms, including glycosylation and recognition of the peptidoglycan substrate. We show that the long cell chains of E. faecalis mutants are more susceptible to phagocytosis and are no longer able to cause lethality in the zebrafish model of infection. Altogether, this work indicates that control of cell separation during division underpins the pathogenesis of E. faecalis infections and represents a novel enterococcal virulence factor. We propose that inhibition of septum cleavage during division represents an attractive therapeutic strategy to control infections. PMID:28742152

Genomic Microbial Epidemiology Is Needed to Comprehend the Global Problem of Antibiotic Resistance and to Improve Pathogen Diagnosis.

PubMed

Wyrsch, Ethan R; Roy Chowdhury, Piklu; Chapman, Toni A; Charles, Ian G; Hammond, Jeffrey M; Djordjevic, Steven P

2016-01-01

Contamination of waste effluent from hospitals and intensive food animal production with antimicrobial residues is an immense global problem. Antimicrobial residues exert selection pressures that influence the acquisition of antimicrobial resistance and virulence genes in diverse microbial populations. Despite these concerns there is only a limited understanding of how antimicrobial residues contribute to the global problem of antimicrobial resistance. Furthermore, rapid detection of emerging bacterial pathogens and strains with resistance to more than one antibiotic class remains a challenge. A comprehensive, sequence-based genomic epidemiological surveillance model that captures essential microbial metadata is needed, both to improve surveillance for antimicrobial resistance and to monitor pathogen evolution. Escherichia coli is an important pathogen causing both intestinal [intestinal pathogenic E. coli (IPEC)] and extraintestinal [extraintestinal pathogenic E. coli (ExPEC)] disease in humans and food animals. ExPEC are the most frequently isolated Gram negative pathogen affecting human health, linked to food production practices and are often resistant to multiple antibiotics. Cattle are a known reservoir of IPEC but they are not recognized as a source of ExPEC that impact human or animal health. In contrast, poultry are a recognized source of multiple antibiotic resistant ExPEC, while swine have received comparatively less attention in this regard. Here, we review what is known about ExPEC in swine and how pig production contributes to the problem of antibiotic resistance.

Experimental Evidence for Reduced Rodent Diversity Causing Increased Hantavirus Prevalence

PubMed Central

Suzán, Gerardo; Marcé, Erika; Giermakowski, J. Tomasz; Mills, James N.; Ceballos, Gerardo; Ostfeld, Richard S.; Armién, Blas; Pascale, Juan M.; Yates, Terry L.

2009-01-01

Emerging and re-emerging infectious diseases have become a major global environmental problem with important public health, economic, and political consequences. The etiologic agents of most emerging infectious diseases are zoonotic, and anthropogenic environmental changes that affect wildlife communities are increasingly implicated in disease emergence and spread. Although increased disease incidence has been correlated with biodiversity loss for several zoonoses, experimental tests in these systems are lacking. We manipulated small-mammal biodiversity by removing non-reservoir species in replicated field plots in Panama, where zoonotic hantaviruses are endemic. Both infection prevalence of hantaviruses in wild reservoir (rodent) populations and reservoir population density increased where small-mammal species diversity was reduced. Regardless of other variables that affect the prevalence of directly transmitted infections in natural communities, high biodiversity is important in reducing transmission of zoonotic pathogens among wildlife hosts. Our results have wide applications in both conservation biology and infectious disease management. PMID:19421313

Influenza: forecast for a pandemic.

PubMed

de la Barrera, Claudia Alvarado; Reyes-Terán, Gustavo

2005-01-01

Recently, great speculation about a possible influenza pandemic has been made. However, the facts supporting the possibility of this threat are less discussed. During the last decade highly pathogenic strains of avian influenza virus, including the H5N1 subtype, crossed the species barriers from birds to humans and caused fatal disease. The Z strain of H5N1 subtype is characterized by pathogenicity to a larger number of animal species and by resistance to the older class of antiviral drugs. At present, two out of three general conditions for the onset of a pandemic have been met; namely, the emergence of a new virus and its ability to replicate in humans causing serious illness. Should the virus achieve efficient human-to-human transmission, the next influenza pandemic might occur. This review addresses these biological and epidemiological aspects of influenza in the context of history and characteristics of previous epidemics, as well as concrete actions that can be undertaken considering current understanding of influenza pathogenesis, treatment, and control possibilities.

Genomic insights into the Ixodes scapularis tick vector of Lyme disease

PubMed Central

Gulia-Nuss, Monika; Nuss, Andrew B.; Meyer, Jason M.; Sonenshine, Daniel E.; Roe, R. Michael; Waterhouse, Robert M.; Sattelle, David B.; de la Fuente, José; Ribeiro, Jose M.; Megy, Karine; Thimmapuram, Jyothi; Miller, Jason R.; Walenz, Brian P.; Koren, Sergey; Hostetler, Jessica B.; Thiagarajan, Mathangi; Joardar, Vinita S.; Hannick, Linda I.; Bidwell, Shelby; Hammond, Martin P.; Young, Sarah; Zeng, Qiandong; Abrudan, Jenica L.; Almeida, Francisca C.; Ayllón, Nieves; Bhide, Ketaki; Bissinger, Brooke W.; Bonzon-Kulichenko, Elena; Buckingham, Steven D.; Caffrey, Daniel R.; Caimano, Melissa J.; Croset, Vincent; Driscoll, Timothy; Gilbert, Don; Gillespie, Joseph J.; Giraldo-Calderón, Gloria I.; Grabowski, Jeffrey M.; Jiang, David; Khalil, Sayed M. S.; Kim, Donghun; Kocan, Katherine M.; Koči, Juraj; Kuhn, Richard J.; Kurtti, Timothy J.; Lees, Kristin; Lang, Emma G.; Kennedy, Ryan C.; Kwon, Hyeogsun; Perera, Rushika; Qi, Yumin; Radolf, Justin D.; Sakamoto, Joyce M.; Sánchez-Gracia, Alejandro; Severo, Maiara S.; Silverman, Neal; Šimo, Ladislav; Tojo, Marta; Tornador, Cristian; Van Zee, Janice P.; Vázquez, Jesús; Vieira, Filipe G.; Villar, Margarita; Wespiser, Adam R.; Yang, Yunlong; Zhu, Jiwei; Arensburger, Peter; Pietrantonio, Patricia V.; Barker, Stephen C.; Shao, Renfu; Zdobnov, Evgeny M.; Hauser, Frank; Grimmelikhuijzen, Cornelis J. P.; Park, Yoonseong; Rozas, Julio; Benton, Richard; Pedra, Joao H. F.; Nelson, David R.; Unger, Maria F.; Tubio, Jose M. C.; Tu, Zhijian; Robertson, Hugh M.; Shumway, Martin; Sutton, Granger; Wortman, Jennifer R.; Lawson, Daniel; Wikel, Stephen K.; Nene, Vishvanath M.; Fraser, Claire M.; Collins, Frank H.; Birren, Bruce; Nelson, Karen E.; Caler, Elisabet; Hill, Catherine A.

2016-01-01

Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ∼57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick–host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host ‘questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent. PMID:26856261

Targeting channels and transporters in protozoan parasite infections

NASA Astrophysics Data System (ADS)

Meier, Anna; Erler, Holger; Beitz, Eric

2018-03-01

Infectious diseases caused by pathogenic protozoa are among the most significant causes of death in humans. Therapeutic options are scarce and massively challenged by the emergence of resistant parasite strains. Many of the current anti-parasite drugs target soluble enzymes, generate unspecific oxidative stress, or act by an unresolved mechanism within the parasite. In recent years, collections of drug-like compounds derived from large-scale phenotypic screenings, such as the malaria or pathogen box, have been made available to researchers free of charge boosting the identification of novel promising targets. Remarkably, several of the compound hits have been found to inhibit membrane proteins at the periphery of the parasites, i.e. channels and transporters for ions and metabolites. In this review, we will focus on the progress made on targeting channels and transporters at different levels and the potential for use against infections with apicomplexan parasites mainly Plasmodium spp. (malaria) and Toxoplasma gondii (toxoplasmosis), with kinetoplastids Trypanosoma brucei (sleeping sickness), Trypanosoma cruzi (Chagas disease) and Leishmania ssp. (leishmaniasis), and the amoeba Entamoeba histolytica (amoebiasis).

Genomic insights into the Ixodes scapularis tick vector of Lyme disease.

PubMed

Gulia-Nuss, Monika; Nuss, Andrew B; Meyer, Jason M; Sonenshine, Daniel E; Roe, R Michael; Waterhouse, Robert M; Sattelle, David B; de la Fuente, José; Ribeiro, Jose M; Megy, Karine; Thimmapuram, Jyothi; Miller, Jason R; Walenz, Brian P; Koren, Sergey; Hostetler, Jessica B; Thiagarajan, Mathangi; Joardar, Vinita S; Hannick, Linda I; Bidwell, Shelby; Hammond, Martin P; Young, Sarah; Zeng, Qiandong; Abrudan, Jenica L; Almeida, Francisca C; Ayllón, Nieves; Bhide, Ketaki; Bissinger, Brooke W; Bonzon-Kulichenko, Elena; Buckingham, Steven D; Caffrey, Daniel R; Caimano, Melissa J; Croset, Vincent; Driscoll, Timothy; Gilbert, Don; Gillespie, Joseph J; Giraldo-Calderón, Gloria I; Grabowski, Jeffrey M; Jiang, David; Khalil, Sayed M S; Kim, Donghun; Kocan, Katherine M; Koči, Juraj; Kuhn, Richard J; Kurtti, Timothy J; Lees, Kristin; Lang, Emma G; Kennedy, Ryan C; Kwon, Hyeogsun; Perera, Rushika; Qi, Yumin; Radolf, Justin D; Sakamoto, Joyce M; Sánchez-Gracia, Alejandro; Severo, Maiara S; Silverman, Neal; Šimo, Ladislav; Tojo, Marta; Tornador, Cristian; Van Zee, Janice P; Vázquez, Jesús; Vieira, Filipe G; Villar, Margarita; Wespiser, Adam R; Yang, Yunlong; Zhu, Jiwei; Arensburger, Peter; Pietrantonio, Patricia V; Barker, Stephen C; Shao, Renfu; Zdobnov, Evgeny M; Hauser, Frank; Grimmelikhuijzen, Cornelis J P; Park, Yoonseong; Rozas, Julio; Benton, Richard; Pedra, Joao H F; Nelson, David R; Unger, Maria F; Tubio, Jose M C; Tu, Zhijian; Robertson, Hugh M; Shumway, Martin; Sutton, Granger; Wortman, Jennifer R; Lawson, Daniel; Wikel, Stephen K; Nene, Vishvanath M; Fraser, Claire M; Collins, Frank H; Birren, Bruce; Nelson, Karen E; Caler, Elisabet; Hill, Catherine A

2016-02-09

Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ∼57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick-host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host 'questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent.

Multiple major disease-associated clones of Legionella pneumophila have emerged recently and independently

PubMed Central

David, Sophia; Rusniok, Christophe; Mentasti, Massimo; Gomez-Valero, Laura; Harris, Simon R.; Lechat, Pierre; Lees, John; Ginevra, Christophe; Glaser, Philippe; Ma, Laurence; Bouchier, Christiane; Underwood, Anthony; Jarraud, Sophie; Harrison, Timothy G.; Parkhill, Julian; Buchrieser, Carmen

2016-01-01

Legionella pneumophila is an environmental bacterium and the leading cause of Legionnaires’ disease. Just five sequence types (ST), from more than 2000 currently described, cause nearly half of disease cases in northwest Europe. Here, we report the sequence and analyses of 364 L. pneumophila genomes, including 337 from the five disease-associated STs and 27 representative of the species diversity. Phylogenetic analyses revealed that the five STs have independent origins within a highly diverse species. The number of de novo mutations is extremely low with maximum pairwise single-nucleotide polymorphisms (SNPs) ranging from 19 (ST47) to 127 (ST1), which suggests emergences within the last century. Isolates sampled geographically far apart differ by only a few SNPs, demonstrating rapid dissemination. These five STs have been recombining recently, leading to a shared pool of allelic variants potentially contributing to their increased disease propensity. The oldest clone, ST1, has spread globally; between 1940 and 2000, four new clones have emerged in Europe, which show long-distance, rapid dispersal. That a large proportion of clinical cases is caused by recently emerged and internationally dispersed clones, linked by convergent evolution, is surprising for an environmental bacterium traditionally considered to be an opportunistic pathogen. To simultaneously explain recent emergence, rapid spread and increased disease association, we hypothesize that these STs have adapted to new man-made environmental niches, which may be linked by human infection and transmission. PMID:27662900

Multiple major disease-associated clones of Legionella pneumophila have emerged recently and independently.

PubMed

David, Sophia; Rusniok, Christophe; Mentasti, Massimo; Gomez-Valero, Laura; Harris, Simon R; Lechat, Pierre; Lees, John; Ginevra, Christophe; Glaser, Philippe; Ma, Laurence; Bouchier, Christiane; Underwood, Anthony; Jarraud, Sophie; Harrison, Timothy G; Parkhill, Julian; Buchrieser, Carmen

2016-11-01

Legionella pneumophila is an environmental bacterium and the leading cause of Legionnaires' disease. Just five sequence types (ST), from more than 2000 currently described, cause nearly half of disease cases in northwest Europe. Here, we report the sequence and analyses of 364 L. pneumophila genomes, including 337 from the five disease-associated STs and 27 representative of the species diversity. Phylogenetic analyses revealed that the five STs have independent origins within a highly diverse species. The number of de novo mutations is extremely low with maximum pairwise single-nucleotide polymorphisms (SNPs) ranging from 19 (ST47) to 127 (ST1), which suggests emergences within the last century. Isolates sampled geographically far apart differ by only a few SNPs, demonstrating rapid dissemination. These five STs have been recombining recently, leading to a shared pool of allelic variants potentially contributing to their increased disease propensity. The oldest clone, ST1, has spread globally; between 1940 and 2000, four new clones have emerged in Europe, which show long-distance, rapid dispersal. That a large proportion of clinical cases is caused by recently emerged and internationally dispersed clones, linked by convergent evolution, is surprising for an environmental bacterium traditionally considered to be an opportunistic pathogen. To simultaneously explain recent emergence, rapid spread and increased disease association, we hypothesize that these STs have adapted to new man-made environmental niches, which may be linked by human infection and transmission. © 2016 David et al.; Published by Cold Spring Harbor Laboratory Press.

Bovine herpes virus-1 (BoHV-1) in cattle–a review with emphasis on reproductive impacts and the emergence of infection in Ireland and the United Kingdom

PubMed Central

2013-01-01

Bovine reproductive disease attributable to bovine herpes virus-1 (BoHV-1) was first described in Germany in the 19th century, being recognised primarily as the cause of infectious vulvovaginitis and balanoposthitis until the mid-1950s when a more virulent strain of the virus (BoHV-1.1) associated with respiratory disease (infectious bovine rhinotracheitis; IBR) emerged in the western United States. Subsequently, IBR emerged as a clinical condition in Europe, from the 1970s onward. While the ability of BoHV-1 to produce respiratory disease is now well recognised, the potential negative outcomes of infection on fertility and reproduction are less frequently considered. This review was conducted against the background of the prioritization of disease caused by BoHV-1 as one of several diseases to be addressed by Animal Health Ireland, with the twin goals of summarizing the published literature on the potential outcomes of infection at different stages of breeding and pregnancy, and of describing the emergence of BoHV-1 as a significant pathogen in Ireland and the UK. PMID:23916092

Emergence of Atypical Mycoplasma agalactiae Strains Harboring a New Prophage and Associated with an Alpine Wild Ungulate Mortality Episode

PubMed Central

Tardy, Florence; Baranowski, Eric; Nouvel, Laurent-Xavier; Mick, Virginie; Manso-Silvàn, Lucía; Thiaucourt, François; Thébault, Patricia; Breton, Marc; Sirand-Pugnet, Pascal; Blanchard, Alain; Garnier, Alexandre; Gibert, Philippe; Game, Yvette; Poumarat, François

2012-01-01

The bacterium Mycoplasma agalactiae is responsible for contagious agalactia (CA) in small domestic ruminants, a syndrome listed by the World Organization for Animal Health and responsible for severe damage to the dairy industry. Recently, we frequently isolated this pathogen from lung lesions of ibexes during a mortality episode in the French Alps. This situation was unusual in terms of host specificity and tissue tropism, raising the question of M. agalactiae emergence in wildlife. To address this issue, the ibex isolates were characterized using a combination of approaches that included antigenic profiles, molecular typing, optical mapping, and whole-genome sequencing. Genome analyses showed the presence of a new, large prophage containing 35 coding sequences (CDS) that was detected in most but not all ibex strains and has a homolog in Mycoplasma conjunctivae, a species causing keratoconjunctivitis in wild ungulates. This and the presence in all strains of large integrated conjugative elements suggested highly dynamic genomes. Nevertheless, M. agalactiae strains circulating in the ibex population were shown to be highly related, most likely originating from a single parental clone that has also spread to another wild ungulate species of the same geographical area, the chamois. These strains clearly differ from strains described in Europe so far, including those found nearby, before CA eradication a few years ago. While M. agalactiae pathogenicity in ibexes remains unclear, our data showed the emergence of atypical strains in Alpine wild ungulates, raising the question of a role for the wild fauna as a potential reservoir of pathogenic mycoplasmas. PMID:22522685

European surveillance of emerging pathogens associated with canine infectious respiratory disease.

PubMed

Mitchell, Judy A; Cardwell, Jacqueline M; Leach, Heather; Walker, Caray A; Le Poder, Sophie; Decaro, Nicola; Rusvai, Miklos; Egberink, Herman; Rottier, Peter; Fernandez, Mireia; Fragkiadaki, Eirini; Shields, Shelly; Brownlie, Joe

2017-12-01

Canine infectious respiratory disease (CIRD) is a major cause of morbidity in dogs worldwide, and is associated with a number of new and emerging pathogens. In a large multi-centre European study the prevalences of four key emerging CIRD pathogens; canine respiratory coronavirus (CRCoV), canine pneumovirus (CnPnV), influenza A, and Mycoplasma cynos (M. cynos); were estimated, and risk factors for exposure, infection and clinical disease were investigated. CIRD affected 66% (381/572) of the dogs studied, including both pet and kennelled dogs. Disease occurrence and severity were significantly reduced in dogs vaccinated against classic CIRD agents, canine distemper virus (CDV), canine adenovirus 2 (CAV-2) and canine parainfluenza virus (CPIV), but substantial proportions (65.7%; 201/306) of vaccinated dogs remained affected. CRCoV and CnPnV were highly prevalent across the different dog populations, with overall seropositivity and detection rates of 47% and 7.7% for CRCoV, and 41.7% and 23.4% for CnPnV, respectively, and their presence was associated with increased occurrence and severity of clinical disease. Antibodies to CRCoV had a protective effect against CRCoV infection and more severe clinical signs of CIRD but antibodies to CnPnV did not. Involvement of M. cynos and influenza A in CIRD was less apparent. Despite 45% of dogs being seropositive for M. cynos, only 0.9% were PCR positive for M. cynos. Only 2.7% of dogs were seropositive for Influenza A, and none were positive by PCR. Copyright © 2017 Elsevier B.V. All rights reserved.

Cranial Mesenteric Arterial Obstruction Due To Strongylus vulgaris Larvae in a Donkey (Equus asinus).

PubMed

Borji, Hassan; Moosavi, Zahra; Ahmadi, Fatemeh

2014-09-01

Arteritis due to Strongylus vulgaris is a well-known cause of colic in horses and donkeys. The current report describes a fatal incidence of arterial obstruction in cranial mesenteric artery caused by S. vulgaris infection in an adult donkey in which anthelmintic treatment was not regularly administered. Necropsy findings of the abdominal cavity revealed a complete cranial mesenteric arterial obstruction due to larvae of S. vulgaris, causing severe colic. To the authors' knowledge, a complete cranial mesenteric arterial obstruction due to verminous arteritis has rarely been described in horses and donkeys. Based on recent reports of fatal arterial obstruction due to S. vulgaris infection in donkeys, it may be evident to consider acute colic caused by this pathogenic parasite a re-emerging disease in donkeys and horses.

Characterization of Two Metal Binding Lipoproteins as Vaccine Candidates for Enterococcal Infections

PubMed Central

Romero-Saavedra, Felipe; Laverde, Diana; Budin-Verneuil, Aurélie; Muller, Cécile; Bernay, Benoit; Benachour, Abdellah; Hartke, Axel; Huebner, Johannes

2015-01-01

Background Enterococcus faecium and faecalis are Gram-positive opportunistic pathogens that have become leading causes of nosocomial infections over the last decades. Especially multidrug resistant enterococci have become a challenging clinical problem worldwide. Therefore, new treatment options are needed and the identification of alternative targets for vaccine development has emerged as a feasible alternative to fight the infections caused by these pathogens. Results We extrapolate the transcriptomic data from a mice peritonitis infection model in E. faecalis to identify putative up-regulated surface proteins under infection conditions in E. faecium. After the bionformatic analyses two metal binding lipoproteins were identified to have a high homology (>72%) between the two species, the manganese ABC transporter substrate-binding lipoprotein (PsaAfm,) and the zinc ABC transporter substrate-binding lipoprotein (AdcAfm). These candidate lipoproteins were overexpressed in Escherichia coli and purified. The recombinant proteins were used to produce rabbit polyclonal antibodies that were able to induce specific opsonic antibodies that mediated killing of the homologous strain E. faecium E155 as well as clinical strains E. faecium E1162, Enterococcus faecalis 12030, type 2 and type 5. Mice were passively immunized with the antibodies raised against recombinant lipoproteins, showing significant reduction of colony counts in mice livers after the bacterial challenge and demonstrating the efficacy of these metal binding lipoproteins as promising vaccine candidates to treat infections caused by these enterococcal pathogens. Conclusion Overall, our results demonstrate that these two metal binding lipoproteins elicited specific, opsonic and protective antibodies, with an extensive cross-reactivity and serotype-independent coverage among these two important nocosomial pathogens. Pointing these two protein antigens as promising immunogens, that can be used as single components or as carrier proteins together with polysaccharide antigens in vaccine development against enterococcal infections. PMID:26322633

Case report: lymphogranuloma venereum proctitis-from rapid screening to molecular confirmation of a masked sexually transmitted disease.

PubMed

Markowicz, Mateusz; Grilnberger, Evelyn; Huber, Florian; Leibl, Gabriele; Abrahamian, Heidemarie; Gartner, Manfred; Huber, Monika; Chott, Andreas; Reiter, Michael; Stanek, Gerold

2013-08-01

Proctitis caused by Chlamydia trachomatis L2b can manifest with very mild, nonspecific symptoms, and appropriate diagnostic evaluation is crucial. The case report demonstrates that rapid screening test, detection of specific antibodies in serum, and direct pathogen identification by PCR performed on tissue sample or rectal swab allow successful diagnosis of the still emerging sexually transmitted disease among homosexual patients. Copyright © 2013 Elsevier Inc. All rights reserved.

Evolutionary genomics of Staphylococcus aureus: insights into the origin of methicillin-resistant strains and the toxic shock syndrome epidemic.

PubMed

Fitzgerald, J R; Sturdevant, D E; Mackie, S M; Gill, S R; Musser, J M

2001-07-17

An emerging theme in medical microbiology is that extensive variation exists in gene content among strains of many pathogenic bacterial species. However, this topic has not been investigated on a genome scale with strains recovered from patients with well-defined clinical conditions. Staphylococcus aureus is a major human pathogen and also causes economically important infections in cows and sheep. A DNA microarray representing >90% of the S. aureus genome was used to characterize genomic diversity, evolutionary relationships, and virulence gene distribution among 36 strains of divergent clonal lineages, including methicillin-resistant strains and organisms causing toxic shock syndrome. Genetic variation in S. aureus is very extensive, with approximately 22% of the genome comprised of dispensable genetic material. Eighteen large regions of difference were identified, and 10 of these regions have genes that encode putative virulence factors or proteins mediating antibiotic resistance. We find that lateral gene transfer has played a fundamental role in the evolution of S. aureus. The mec gene has been horizontally transferred into distinct S. aureus chromosomal backgrounds at least five times, demonstrating that methicillin-resistant strains have evolved multiple independent times, rather than from a single ancestral strain. This finding resolves a long-standing controversy in S. aureus research. The epidemic of toxic shock syndrome that occurred in the 1970s was caused by a change in the host environment, rather than rapid geographic dissemination of a new hypervirulent strain. DNA microarray analysis of large samples of clinically characterized strains provides broad insights into evolution, pathogenesis, and disease emergence.

Emerging Tuberculosis Pathogen Hijacks Social Communication Behavior in the Group-Living Banded Mongoose (Mungos mungo)

PubMed Central

Sanderson, Claire E.; Larsen, Michelle H.; Robbe-Austerman, Suelee; Williams, Mark C.; Palmer, Mitchell V.

2016-01-01

ABSTRACT An emerging Mycobacterium tuberculosis complex (MTC) pathogen, M. mungi, infects wild banded mongooses (Mungos mungo) in Northern Botswana, causing significant mortality. This MTC pathogen did not appear to be transmitted through a primary aerosol or oral route. We utilized histopathology, spoligotyping, mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR), quantitative PCR (qPCR), and molecular markers (regions of difference [RDs] from various MTC members, including region of difference 1 [RD1] from M. bovis BCG [RD1BCG], M. microti [RD1mic], and M. pinnipedii [RD1seal], genes Rv1510 [RD4], Rv1970 [RD7], Rv3877/8 [RD1], and Rv3120 [RD12], insertion element IS1561, the 16S RNA gene, and gene Rv0577 [cfp32]), including the newly characterized mongoose-specific deletion in RD1 (RD1mon), in order to demonstrate the presence of M. mungi DNA in infected mongooses and investigate pathogen invasion and exposure mechanisms. M. mungi DNA was identified in 29% of nasal planum samples (n = 52), 56% of nasal rinses and swabs (n = 9), 53% of oral swabs (n = 19), 22% of urine samples (n = 23), 33% of anal gland tissue (n = 18), and 39% of anal gland secretions (n = 44). The occurrence of extremely low cycle threshold values obtained with qPCR in anal gland and nasal planum samples indicates that high levels of M. mungi can be found in these tissue types. Histological data were consistent with these results, suggesting that pathogen invasion occurs through breaks in the nasal planum and/or skin of the mongoose host, which are in frequent contact with anal gland secretions and urine during olfactory communication behavior. Lesions in the lung, when present, occurred only with disseminated disease. No environmental sources of M. mungi DNA could be found. We report primary environmental transmission of an MTC pathogen that occurs in association with social communication behavior. PMID:27165798

Quantifying the Evolutionary Conservation of Genes Encoding Multidrug Efflux Pumps in the ESKAPE Pathogens To Identify Antimicrobial Drug Targets.

PubMed

Brooks, Lauren E; Ul-Hasan, Sabah; Chan, Benjamin K; Sistrom, Mark J

2018-01-01

Increasing rates of antibiotic-resistant bacterial infection are one of the most pressing contemporary global health concerns. The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) have been identified as the leading global cause of multidrug-resistant bacterial infections, and overexpression of multidrug efflux (MEX) transport systems has been identified as one of the most critical mechanisms facilitating the evolution of multidrug resistance in ESKAPE pathogens. Despite efforts to develop efflux pump inhibitors to combat antibiotic resistance, the need persists to identify additional targets for future investigations. We evaluated evolutionary pressures on 110 MEX-encoding genes from all annotated ESKAPE organism genomes. We identify several MEX genes under stabilizing selection-representing targets which can facilitate broad-spectrum treatments with evolutionary constraints limiting the potential emergence of escape mutants. We also examine MEX systems being evaluated as drug targets, demonstrating that divergent selection may underlie some of the problems encountered in the development of effective treatments-specifically in relation to the NorA system in S. aureus. This study provides a comprehensive evolutionary context to efflux in the ESKAPE pathogens, which will provide critical context to the evaluation of efflux systems as antibiotic targets. IMPORTANCE Increasing rates of antibiotic-resistant bacterial infection are one of the most pressing contemporary global health concerns. The ESKAPE pathogen group represents the leading cause of these infections, and upregulation of efflux pump expression is a significant mechanism of resistance in these pathogens. This has resulted in substantial interest in the development of efflux pump inhibitors to combat antibiotic-resistant infections; however, no widespread treatments have been developed to date. Our study evaluates an often-underappreciated aspect of resistance-the impact of evolutionary selection. We evaluate selection on all annotated efflux genes in all sequenced ESKAPE pathogens, providing critical context for and insight into current and future development of efflux-targeting treatments for resistant bacterial infections.

Quantifying the Evolutionary Conservation of Genes Encoding Multidrug Efflux Pumps in the ESKAPE Pathogens To Identify Antimicrobial Drug Targets

PubMed Central

Ul-Hasan, Sabah; Chan, Benjamin K.; Sistrom, Mark J.

2018-01-01

ABSTRACT Increasing rates of antibiotic-resistant bacterial infection are one of the most pressing contemporary global health concerns. The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) have been identified as the leading global cause of multidrug-resistant bacterial infections, and overexpression of multidrug efflux (MEX) transport systems has been identified as one of the most critical mechanisms facilitating the evolution of multidrug resistance in ESKAPE pathogens. Despite efforts to develop efflux pump inhibitors to combat antibiotic resistance, the need persists to identify additional targets for future investigations. We evaluated evolutionary pressures on 110 MEX-encoding genes from all annotated ESKAPE organism genomes. We identify several MEX genes under stabilizing selection—representing targets which can facilitate broad-spectrum treatments with evolutionary constraints limiting the potential emergence of escape mutants. We also examine MEX systems being evaluated as drug targets, demonstrating that divergent selection may underlie some of the problems encountered in the development of effective treatments—specifically in relation to the NorA system in S. aureus. This study provides a comprehensive evolutionary context to efflux in the ESKAPE pathogens, which will provide critical context to the evaluation of efflux systems as antibiotic targets. IMPORTANCE Increasing rates of antibiotic-resistant bacterial infection are one of the most pressing contemporary global health concerns. The ESKAPE pathogen group represents the leading cause of these infections, and upregulation of efflux pump expression is a significant mechanism of resistance in these pathogens. This has resulted in substantial interest in the development of efflux pump inhibitors to combat antibiotic-resistant infections; however, no widespread treatments have been developed to date. Our study evaluates an often-underappreciated aspect of resistance—the impact of evolutionary selection. We evaluate selection on all annotated efflux genes in all sequenced ESKAPE pathogens, providing critical context for and insight into current and future development of efflux-targeting treatments for resistant bacterial infections. PMID:29719870

Recent Trends in Salmonella Outbreaks and Emerging Technology for Biocontrol of Salmonella Using Phages in Foods: A Review.

PubMed

Oh, Jun-Hyun; Park, Mi-Kyung

2017-12-28

Salmonella is one of the principal causes of foodborne outbreaks. As traditional control methods have shown less efficacy against emerging Salmonella serotypes or antimicrobialresistant Salmonella , new approaches have been attempted. The use of lytic phages for the biocontrol of Salmonella in the food industry has become an attractive method owing to the many advantages offered by the use of phages as biocontrol agents. Phages are natural alternatives to traditional antimicrobial agents; they have proven effective in the control of bacterial pathogens in the food industry, which has led to the development of different phage products. The treatment with specific phages in the food industry can prevent the decay of products and the spread of bacterial diseases, and ultimately promotes safe environments for animal and plant food production, processing, and handling. After an extensive investigation of the current literature, this review focuses predominantly on the efficacy of phages for the successful control of Salmonella spp. in foods. This review also addresses the current knowledge on the pathogenic characteristics of Salmonella , the prevalence of emerging Salmonella outbreaks, the isolation and characterization of Salmonella -specific phages, the effectiveness of Salmonella -specific phages as biocontrol agents, and the prospective use of Salmonella -specific phages in the food industry.

Emerging issues, challenges, and changing epidemiology of fungal disease outbreaks.

PubMed

Benedict, Kaitlin; Richardson, Malcolm; Vallabhaneni, Snigdha; Jackson, Brendan R; Chiller, Tom

2017-12-01

Several high-profile outbreaks have drawn attention to invasive fungal infections (IFIs) as an increasingly important public health problem. IFI outbreaks are caused by many different fungal pathogens and are associated with numerous settings and sources. In the community, IFI outbreaks often occur among people without predisposing medical conditions and are frequently precipitated by environmental disruption. Health-care-associated IFI outbreaks have been linked to suboptimal hospital environmental conditions, transmission via health-care workers' hands, contaminated medical products, and transplantation of infected organs. Outbreak investigations provide important insights into the epidemiology of IFIs, uncover risk factors for infection, and identify opportunities for preventing similar events in the future. Well recognised challenges with IFI outbreak recognition, response, and prevention include the need for improved rapid diagnostic methods, the absence of routine surveillance for most IFIs, adherence to infection control practices, and health-care provider awareness. Additionally, IFI outbreak investigations have revealed several emerging issues, including new populations at risk because of travel or relocation, occupation, or immunosuppression; fungal pathogens appearing in geographical areas in which they have not been previously recognised; and contaminated compounded medications. This report highlights notable IFI outbreaks in the past decade, with an emphasis on these emerging challenges in the USA. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evolution of community- and healthcare-associated methicillin-resistant Staphylococcus aureus☆

PubMed Central

Uhlemann, Anne-Catrin; Otto, Michael; Lowy, Franklin D.; DeLeo, Frank R.

2013-01-01

Staphylococcus aureus is a prominent cause of human infections globally. The high prevalence of infections is compounded by antibiotic resistance—a significant problem for treatment. Methicillin-resistant S. aureus (MRSA) is endemic in hospitals and healthcare facilities worldwide, and is an increasingly common cause of community-associated bacterial infections in industrialized countries. Although much focus is placed on the role of S. aureus as a human pathogen, it is in fact a human commensal organism that has had a relatively long coexistence with the human host. Many S. aureus infections can be explained by host susceptibility or other predisposing risk factors. On the other hand, the emergence/re-emergence of successful S. aureus clones (referred to as epidemic waves) suggests a rapid bacterial adaption and evolution, which includes the emergence of antibiotic resistance and increased virulence and/or transmissibility. It is within this context that we review our understanding of selected S. aureus epidemic waves, and highlight the use of genome sequencing as a means to better understand the evolution of each lineage. PMID:23648426

Wildlife trade and global disease emergence.

PubMed

Karesh, William B; Cook, Robert A; Bennett, Elizabeth L; Newcomb, James

2005-07-01

The global trade in wildlife provides disease transmission mechanisms that not only cause human disease outbreaks but also threaten livestock, international trade, rural livelihoods, native wildlife populations, and the health of ecosystems. Outbreaks resulting from wildlife trade have caused hundreds of billions of dollars of economic damage globally. Rather than attempting to eradicate pathogens or the wild species that may harbor them, a practical approach would include decreasing the contact rate among species, including humans, at the interface created by the wildlife trade. Since wildlife marketing functions as a system of scale-free networks with major hubs, these points provide control opportunities to maximize the effects of regulatory efforts.

Multi-omics Analysis Sheds Light on the Evolution and the Intracellular Lifestyle Strategies of Spotted Fever Group Rickettsia spp.

PubMed Central

El Karkouri, Khalid; Kowalczewska, Malgorzata; Armstrong, Nicholas; Azza, Said; Fournier, Pierre-Edouard; Raoult, Didier

2017-01-01

Arthropod-borne Rickettsia species are obligate intracellular bacteria which are pathogenic for humans. Within this genus, Rickettsia slovaca and Rickettsia conorii cause frequent and potentially severe infections, whereas Rickettsia raoultii and Rickettsia massiliae cause rare and milder infections. All four species belong to spotted fever group (SFG) rickettsiae. However, R. slovaca and R. raoultii cause scalp eschar and neck lymphadenopathy (SENLAT) and are mainly associated with Dermacentor ticks, whereas the other two species cause Mediterranean spotted fever (MSF) and are mainly transmitted by Rhipicephalus ticks. To identify the potential genes and protein profiles and to understand the evolutionary processes that could, comprehensively, relate to the differences in virulence and pathogenicity observed between these four species, we compared their genomes and proteomes. The virulent and milder agents displayed divergent phylogenomic evolution in two major clades, whereas either SENLAT or MSF disease suggests a discrete convergent evolution of one virulent and one milder agent, despite their distant genetic relatedness. Moreover, the two virulent species underwent strong reductive genomic evolution and protein structural variations, as well as a probable loss of plasmid(s), compared to the two milder species. However, an abundance of mobilome genes was observed only in the less pathogenic species. After infecting Xenopus laevis cells, the virulent agents displayed less up-regulated than down-regulated proteins, as well as less number of identified core proteins. Furthermore, their similar and distinct protein profiles did not contain some genes (e.g., ompA/B and rickA) known to be related to rickettsial adhesion, motility and/or virulence, but may include other putative virulence-, antivirulence-, and/or disease-related proteins. The identified evolutionary forces herein may have a strong impact on intracellular expressions and strategies in these rickettsiae, and that may contribute to the emergence of distinct virulence and diseases in humans. Thus, the current multi-omics data provide new insights into the evolution and fitness of SFG virulence and pathogenicity, and intracellular pathogenic bacteria. PMID:28775717

Humans, Evolutionary and Ecologic Forces Shaped the Phylogeography of Recently Emerged Diseases

PubMed Central

Keim, Paul S.; Wagner, David M.

2009-01-01

Many infectious diseases have emerged and circulated around the world with the development of human civilizations and global commerce. Anthrax, plague and tularemia are three such zoonotic diseases that have been intensely studied through genome characterization and phylogeographic analyses. A few highly fit genotypes within each of the causative species represent the vast majority of observed disease cases. Mutational and selective forces working together create highly adapted pathogens, but this has to be coupled with ecological opportunities for global expansion. This Review describes the distributions of the bacteria that cause anthrax, plague and tularemia and investigates the forces that created a clonal structure in both these species, and specific groups within these species. PMID:19820723

The link between rapid enigmatic amphibian decline and the globally emerging chytrid fungus.

PubMed

Lötters, Stefan; Kielgast, Jos; Bielby, Jon; Schmidtlein, Sebastian; Bosch, Jaime; Veith, Michael; Walker, Susan F; Fisher, Matthew C; Rödder, Dennis

2009-09-01

Amphibians are globally declining and approximately one-third of all species are threatened with extinction. Some of the most severe declines have occurred suddenly and for unknown reasons in apparently pristine habitats. It has been hypothesized that these "rapid enigmatic declines" are the result of a panzootic of the disease chytridiomycosis caused by globally emerging amphibian chytrid fungus. In a Species Distribution Model, we identified the potential distribution of this pathogen. Areas and species from which rapid enigmatic decline are known significantly overlap with those of highest environmental suitability to the chytrid fungus. We confirm the plausibility of a link between rapid enigmatic decline in worldwide amphibian species and epizootic chytridiomycosis.

Tackling antibiotic resistance in India.

PubMed

Wattal, Chand; Goel, Neeraj

2014-12-01

Infectious diseases are major causes of mortality in India. This is aggravated by the increasing prevalence of antimicrobial resistance (AMR) both in the community and in hospitals. Due to the emergence of resistance to all effective antibiotics in nosocomial pathogens, the situation calls for emergency measures to tackle AMR in India. India has huge challenges in tackling AMR, ranging from lack of surveillance mechanisms for monitoring AMR and use; effective hospital control policies; sanitation and non-human use of antimicrobial. The Ministry of Health and Family Welfare of Govt. of India has taken initiatives to tackle AMR. Extensive guidelines have been drafted and a model worksheet has been developed as a roadmap to tackle AMR.

The Promise of Whole Genome Pathogen Sequencing for the Molecular Epidemiology of Emerging Aquaculture Pathogens

PubMed Central

Bayliss, Sion C.; Verner-Jeffreys, David W.; Bartie, Kerry L.; Aanensen, David M.; Sheppard, Samuel K.; Adams, Alexandra; Feil, Edward J.

2017-01-01

Aquaculture is the fastest growing food-producing sector, and the sustainability of this industry is critical both for global food security and economic welfare. The management of infectious disease represents a key challenge. Here, we discuss the opportunities afforded by whole genome sequencing of bacterial and viral pathogens of aquaculture to mitigate disease emergence and spread. We outline, by way of comparison, how sequencing technology is transforming the molecular epidemiology of pathogens of public health importance, emphasizing the importance of community-oriented databases and analysis tools. PMID:28217117

In-Frame and Unmarked Gene Deletions in Burkholderia cenocepacia via an Allelic Exchange System Compatible with Gateway Technology.

PubMed

Fazli, Mustafa; Harrison, Joe J; Gambino, Michela; Givskov, Michael; Tolker-Nielsen, Tim

2015-06-01

Burkholderia cenocepacia is an emerging opportunistic pathogen causing life-threatening infections in immunocompromised individuals and in patients with cystic fibrosis, which are often difficult, if not impossible, to treat. Understanding the genetic basis of virulence in this emerging pathogen is important for the development of novel treatment regimes. Generation of deletion mutations in genes predicted to encode virulence determinants is fundamental to investigating the mechanisms of pathogenesis. However, there is a lack of appropriate selectable and counterselectable markers for use in B. cenocepacia, making its genetic manipulation problematic. Here we describe a Gateway-compatible allelic exchange system based on the counterselectable pheS gene and the I-SceI homing endonuclease. This system provides efficiency in cloning homology regions of target genes and allows the generation of precise and unmarked gene deletions in B. cenocepacia. As a proof of concept, we demonstrate its utility by deleting the Bcam1349 gene, encoding a cyclic di-GMP (c-di-GMP)-responsive regulator protein important for biofilm formation. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

In-Frame and Unmarked Gene Deletions in Burkholderia cenocepacia via an Allelic Exchange System Compatible with Gateway Technology

PubMed Central

Fazli, Mustafa; Harrison, Joe J.; Gambino, Michela; Givskov, Michael

2015-01-01

Burkholderia cenocepacia is an emerging opportunistic pathogen causing life-threatening infections in immunocompromised individuals and in patients with cystic fibrosis, which are often difficult, if not impossible, to treat. Understanding the genetic basis of virulence in this emerging pathogen is important for the development of novel treatment regimes. Generation of deletion mutations in genes predicted to encode virulence determinants is fundamental to investigating the mechanisms of pathogenesis. However, there is a lack of appropriate selectable and counterselectable markers for use in B. cenocepacia, making its genetic manipulation problematic. Here we describe a Gateway-compatible allelic exchange system based on the counterselectable pheS gene and the I-SceI homing endonuclease. This system provides efficiency in cloning homology regions of target genes and allows the generation of precise and unmarked gene deletions in B. cenocepacia. As a proof of concept, we demonstrate its utility by deleting the Bcam1349 gene, encoding a cyclic di-GMP (c-di-GMP)-responsive regulator protein important for biofilm formation. PMID:25795676

Germs, genomics and global public health: How can advances in genomic sciences be integrated into public health in the developing world to deal with infectious diseases?

PubMed

Pang, T

2009-12-01

Scientific and technological advances derived from the genomics revolution have a central role to play in dealing with continuing infectious disease threats in the developing world caused by emerging and re-emerging pathogens. These techniques, coupled with increasing knowledge of host-pathogen interactions, can assist in the early identification and containment of outbreaks as well as in the development of preventive vaccination and therapeutic interventions, including the urgent need for new antibiotics. However, the effective application of genomics technologies faces key barriers and challenges which occur at three stages: from the research to the products, from the products to individual patients, and, finally, from patients to entire populations. There needs to be an emphasis on research in areas of greatest need, in facilitating the translation of research into interventions and, finally, the effective delivery of such interventions to those in greatest need. Ultimate success will depend on bringing together science, society and policy to develop effective public health implementation strategies to provide health security and health equity for all peoples.

Genesis and Spread of Newly Emerged Highly Pathogenic H7N9 Avian Viruses in Mainland China

PubMed Central

Yang, Lei; Zhu, Wenfei; Li, Xiyan; Chen, Minmei; Wu, Jie; Yu, Pengbo; Qi, Shunxiang; Huang, Yiwei; Shi, Weixian; Dong, Jie; Zhao, Xiang; Huang, Weijuan; Li, Zi; Zeng, Xiaoxu; Bo, Hong; Chen, Tao; Chen, Wenbing; Liu, Jia; Zhang, Ye; Liang, Zhenli; Shi, Wei

2017-01-01

ABSTRACT The novel low-pathogenic avian influenza A H7N9 viruses (LPAI H7N9 viruses) have been a threat to public health since their emergence in 2013 because of the high rates of mortality and morbidity that they cause. Recently, highly pathogenic variants of these avian influenza A H7N9 viruses (HPAI H7N9 viruses) have emerged and caused human infections and outbreaks among poultry in mainland China. However, it is still unclear how the HPAI H7N9 virus was generated and how it evolved and spread in China. Here, we show that the ancestor virus of the HPAI H7N9 viruses originated in the Yangtze River Delta region and spread southward to the Pearl River Delta region, possibly through live poultry trade. After introduction into the Pearl River Delta region, the origin LPAI H7N9 virus acquired four amino acid insertions in the hemagglutinin (HA) protein cleavage site and mutated into the HPAI H7N9 virus in late May 2016. Afterward, the HPAI H7N9 viruses further reassorted with LPAI H7N9 or H9N2 viruses locally and generated multiple different genotypes. As of 14 July 2017, the HPAI H7N9 viruses had spread from Guangdong Province to at least 12 other provinces. The rapid geographical expansion and genetic evolution of the HPAI H7N9 viruses pose a great challenge not only to public health but also to poultry production. Effective control measures, including enhanced surveillance, are therefore urgently needed. IMPORTANCE The LPAI H7N9 virus has caused five outbreak waves in humans and was recently reported to have mutated into highly pathogenic variants. It is unknown how the HPAI H7N9 virus originated, evolved, and disseminated in China. In this study, we comprehensively analyzed the sequences of HPAI H7N9 viruses from 28 human and 21 environmental samples covering eight provinces in China that were taken from November 2016 to June 2017. The results show that the ancestor virus of the HPAI H7N9 viruses originated in the Yangtze River Delta region. However, the insertion of four amino acids into the HA protein cleavage site of an LPAI H7N9 virus occurred in late May 2016 in the Pearl River Delta region. The mutated HPAI H7N9 virus further reassorted with LPAI H7N9 or H9N2 viruses that were cocirculating in poultry. Considering the rapid geographical expansion of the HPAI H7N9 viruses, effective control measures are urgently needed. PMID:28956760

Dating the Cryptococcus gattii Dispersal to the North American Pacific Northwest

PubMed Central

Roe, Chandler C.; Bowers, Jolene; Oltean, Hanna; DeBess, Emilio; Dufresne, Philippe J.; McBurney, Scott; Overy, David P.; Wanke, Bodo; Lysen, Colleen; Chiller, Tom; Meyer, Wieland; Thompson, George R.; Lockhart, Shawn R.; Hepp, Crystal M.

2018-01-01

ABSTRACT The emergence of Cryptococcus gattii, previously regarded as a predominantly tropical pathogen, in the temperate climate of the North American Pacific Northwest (PNW) in 1999 prompted several questions. The most prevalent among these was the timing of the introduction of this pathogen to this novel environment. Here, we infer tip-dated timing estimates for the three clonal C. gattii populations observed in the PNW, VGIIa, VGIIb, and VGIIc, based on whole-genome sequencing of 134 C. gattii isolates and using Bayesian evolutionary analysis by sampling trees (BEAST). We estimated the nucleotide substitution rate for each lineage (1.59 × 10−8, 1.59 × 10−8, and 2.70 × 10−8, respectively) to be an order of magnitude higher than common neutral fungal mutation rates (2.0 × 10−9), indicating a microevolutionary rate (e.g., successive clonal generations in a laboratory) in comparison to a species’ slower, macroevolutionary rate (e.g., when using fossil records). The clonal nature of the PNW C. gattii emergence over a narrow number of years would therefore possibly explain our higher mutation rates. Our results suggest that the mean time to most recent common ancestor for all three sublineages occurred within the last 60 to 100 years. While the cause of C. gattii dispersal to the PNW is still unclear, our research estimates that the arrival is neither ancient nor very recent (i.e., <25 years ago), making a strong case for an anthropogenic introduction. IMPORTANCE The recent emergence of the pathogenic fungus Cryptococcus gattii in the Pacific Northwest (PNW) resulted in numerous investigations into the epidemiological and enzootic impacts, as well as multiple genomic explorations of the three primary molecular subtypes of the fungus that were discovered. These studies lead to the general conclusion that the subtypes identified likely emerged out of Brazil. Here, we conducted genomic dating analyses to determine the ages of the various lineages seen in the PNW and propose hypothetical causes for the dispersal events. Bayesian evolutionary analysis strongly suggests that these independent fungal populations in the PNW are all 60 to 100 years old, providing a timing that is subsequent to the opening of the Panama Canal, which allowed for more direct shipping between Brazil and the western North American coastline, a possible driving event for these fungal translocation events. PMID:29359190

Dating the Cryptococcus gattii Dispersal to the North American Pacific Northwest.

PubMed

Roe, Chandler C; Bowers, Jolene; Oltean, Hanna; DeBess, Emilio; Dufresne, Philippe J; McBurney, Scott; Overy, David P; Wanke, Bodo; Lysen, Colleen; Chiller, Tom; Meyer, Wieland; Thompson, George R; Lockhart, Shawn R; Hepp, Crystal M; Engelthaler, David M

2018-01-01

The emergence of Cryptococcus gattii , previously regarded as a predominantly tropical pathogen, in the temperate climate of the North American Pacific Northwest (PNW) in 1999 prompted several questions. The most prevalent among these was the timing of the introduction of this pathogen to this novel environment. Here, we infer tip-dated timing estimates for the three clonal C. gattii populations observed in the PNW, VGIIa, VGIIb, and VGIIc, based on whole-genome sequencing of 134 C. gattii isolates and using Bayesian evolutionary analysis by sampling trees (BEAST). We estimated the nucleotide substitution rate for each lineage (1.59 × 10 -8 , 1.59 × 10 -8 , and 2.70 × 10 -8 , respectively) to be an order of magnitude higher than common neutral fungal mutation rates (2.0 × 10 -9 ), indicating a microevolutionary rate (e.g., successive clonal generations in a laboratory) in comparison to a species' slower, macroevolutionary rate (e.g., when using fossil records). The clonal nature of the PNW C. gattii emergence over a narrow number of years would therefore possibly explain our higher mutation rates. Our results suggest that the mean time to most recent common ancestor for all three sublineages occurred within the last 60 to 100 years. While the cause of C. gattii dispersal to the PNW is still unclear, our research estimates that the arrival is neither ancient nor very recent (i.e., <25 years ago), making a strong case for an anthropogenic introduction. IMPORTANCE The recent emergence of the pathogenic fungus Cryptococcus gattii in the Pacific Northwest (PNW) resulted in numerous investigations into the epidemiological and enzootic impacts, as well as multiple genomic explorations of the three primary molecular subtypes of the fungus that were discovered. These studies lead to the general conclusion that the subtypes identified likely emerged out of Brazil. Here, we conducted genomic dating analyses to determine the ages of the various lineages seen in the PNW and propose hypothetical causes for the dispersal events. Bayesian evolutionary analysis strongly suggests that these independent fungal populations in the PNW are all 60 to 100 years old, providing a timing that is subsequent to the opening of the Panama Canal, which allowed for more direct shipping between Brazil and the western North American coastline, a possible driving event for these fungal translocation events.

Evolutionary genomics of yeast pathogens in the Saccharomycotina

PubMed Central

Naranjo-Ortíz, Miguel A.; Marcet-Houben, Marina

2016-01-01

Saccharomycotina comprises a diverse group of yeasts that includes numerous species of industrial or clinical relevance. Opportunistic pathogens within this clade are often assigned to the genus Candida but belong to phylogenetically distant lineages that also comprise non-pathogenic species. This indicates that the ability to infect humans has evolved independently several times among Saccharomycotina. Although the mechanisms of infection of the main groups of Candida pathogens are starting to be unveiled, we still lack sufficient understanding of the evolutionary paths that led to a virulent phenotype in each of the pathogenic lineages. Deciphering what genomic changes underlie the evolutionary emergence of a virulence trait will not only aid the discovery of novel virulence mechanisms but it will also provide valuable information to understand how new pathogens emerge, and what clades may pose a future danger. Here we review recent comparative genomics efforts that have revealed possible evolutionary paths to pathogenesis in different lineages, focusing on the main three agents of candidiasis worldwide: Candida albicans, C. parapsilosis and C. glabrata. We will discuss what genomic traits may facilitate the emergence of virulence, and focus on two different genome evolution mechanisms able to generate drastic phenotypic changes and which have been associated to the emergence of virulence: gene family expansion and interspecies hybridization. PMID:27493146

Recent human-to-poultry host jump, adaptation, and pandemic spread of Staphylococcus aureus

PubMed Central

Lowder, Bethan V.; Guinane, Caitriona M.; Ben Zakour, Nouri L.; Weinert, Lucy A.; Conway-Morris, Andrew; Cartwright, Robyn A.; Simpson, A. John; Rambaut, Andrew; Nübel, Ulrich; Fitzgerald, J. Ross

2009-01-01

The impact of globalization on the emergence and spread of pathogens is an important veterinary and public health issue. Staphylococcus aureus is a notorious human pathogen associated with serious nosocomial and community-acquired infections. In addition, S. aureus is a major cause of animal diseases including skeletal infections of poultry, which are a large economic burden on the global broiler chicken industry. Here, we provide evidence that the majority of S. aureus isolates from broiler chickens are the descendants of a single human-to-poultry host jump that occurred approximately 38 years ago (range, 30 to 63 years ago) by a subtype of the worldwide human ST5 clonal lineage unique to Poland. In contrast to human subtypes of the ST5 radiation, which demonstrate strong geographic clustering, the poultry ST5 clade was distributed in different continents, consistent with wide dissemination via the global poultry industry distribution network. The poultry ST5 clade has undergone genetic diversification from its human progenitor strain by acquisition of novel mobile genetic elements from an avian-specific accessory gene pool, and by the inactivation of several proteins important for human disease pathogenesis. These genetic events have resulted in enhanced resistance to killing by chicken heterophils, reflecting avian host-adaptive evolution. Taken together, we have determined the evolutionary history of a major new animal pathogen that has undergone rapid avian host adaptation and intercontinental dissemination. These data provide a new paradigm for the impact of human activities on the emergence of animal pathogens. PMID:19884497