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Current HIV/AIDS Reports Mar 2015The persistence of human immunodeficiency virus type 1 (HIV-1) in latent reservoirs is a major barrier to HIV cure. Reservoir establishment depends on low viral... (Review)
Review
The persistence of human immunodeficiency virus type 1 (HIV-1) in latent reservoirs is a major barrier to HIV cure. Reservoir establishment depends on low viral expression that may be related to provirus integration sites (IS). In vitro, in cell lines and primary T cells, latency is associated with specific IS through reduced viral expression mediated by transcriptional interference by host cellular promoters, reverse orientation, and the presence of specific epigenetic modifiers. In primary T cell models of latency, specific IS are associated with intracellular viral antigen expression that is not directly related to cell activation. In contrast, in patient CD4+ T cells, there is enrichment for IS in genes controlling cell cycle and survival and in some clonally expanded T cell subpopulations. Multiple insertion sites within some specific genes may suggest that integrated HIV can increase the host's T cell survival.
Topics: Disease Reservoirs; HIV Infections; HIV-1; Humans; Virus Integration; Virus Latency
PubMed: 25573791
DOI: 10.1007/s11904-014-0241-9 -
Biological Reviews of the Cambridge... Jun 2020Enteric illnesses remain the second largest source of communicable diseases worldwide, and wild birds are suspected sources for human infection. This has led to efforts... (Meta-Analysis)
Meta-Analysis Review
Enteric illnesses remain the second largest source of communicable diseases worldwide, and wild birds are suspected sources for human infection. This has led to efforts to reduce pathogen spillover through deterrence of wildlife and removal of wildlife habitat, particularly within farming systems, which can compromise conservation efforts and the ecosystem services wild birds provide. Further, Salmonella spp. are a significant cause of avian mortality, leading to additional conservation concerns. Despite numerous studies of enteric bacteria in wild birds and policies to discourage birds from food systems, we lack a comprehensive understanding of wild bird involvement in transmission of enteric bacteria to humans. Here, we propose a framework for understanding spillover of enteric pathogens from wild birds to humans, which includes pathogen acquisition, reservoir competence and bacterial shedding, contact with people and food, and pathogen survival in the environment. We place the literature into this framework to identify important knowledge gaps. Second, we conduct a meta-analysis of prevalence data for three human enteric pathogens, Campylobacter spp., E. coli, and Salmonella spp., in 431 North American breeding bird species. Our literature review revealed that only 3% of studies addressed the complete system of pathogen transmission. In our meta-analysis, we found a Campylobacter spp. prevalence of 27% across wild birds, while prevalence estimates of pathogenic E. coli (20%) and Salmonella spp. (6.4%) were lower. There was significant bias in which bird species have been tested, with most studies focusing on a small number of taxa that are common near people (e.g. European starlings Sturnus vulgaris and rock pigeons Columba livia) or commonly in contact with human waste (e.g. gulls). No pathogen prevalence data were available for 65% of North American breeding bird species, including many commonly in contact with humans (e.g. black-billed magpie Pica hudsonia and great blue heron Ardea herodias), and our metadata suggest that some under-studied species, taxonomic groups, and guilds may represent equivalent or greater risk to human infection than heavily studied species. We conclude that current data do not provide sufficient information to determine the likelihood of enteric pathogen spillover from wild birds to humans and thus preclude management solutions. The primary focus in the literature on pathogen prevalence likely overestimates the probability of enteric pathogen spillover from wild birds to humans because a pathogen must survive long enough at an infectious dose and be a strain that is able to colonize humans to cause infection. We propose that future research should focus on the large number of under-studied species commonly in contact with people and food production and demonstrate shedding of bacterial strains pathogenic to humans into the environment where people may contact them. Finally, studies assessing the duration and intensity of bacterial shedding and survival of bacteria in the environment in bird faeces will help provide crucial missing information necessary to calculate spillover probability. Addressing these essential knowledge gaps will support policy to reduce enteric pathogen spillover to humans and enhance bird conservation efforts that are currently undermined by unsupported fears of pathogen spillover from wild birds.
Topics: Animal Migration; Animals; Animals, Wild; Bacterial Infections; Bird Diseases; Birds; Disease Reservoirs; Humans; Livestock; Prevalence; Regression Analysis; Risk Factors; Virulence
PubMed: 32003106
DOI: 10.1111/brv.12581 -
Parasite (Paris, France) 2022Leishmania parasites can cause zoonotic cutaneous leishmaniasis (CL) by circulating between humans, rodents, and sandflies in Iran. In this study, published data were... (Review)
Review
Leishmania parasites can cause zoonotic cutaneous leishmaniasis (CL) by circulating between humans, rodents, and sandflies in Iran. In this study, published data were collected from scientific sources such as Web of Science, Scopus, PubMed, Springer, ResearchGate, Wiley Online, Ovid, Ebsco, Cochrane Library, Google scholar, and SID. Keywords searched in the articles, theses, and abstracts from 1983 to 2021 were cutaneous leishmaniasis, epidemiology, reservoir, vector, climatic factors, identification, and Iran. This review revealed that CL was prevalent in the west of Iran, while the center and south of Iran were also involved in recent years. The lack of facilities in suburban regions was an aggravating factor in the human community. Some parts of southern Iran were prominent foci of CL due the presence of potential rodent hosts in these regions. Rhombomys opimus, Meriones lybicus, and Tatera indica were well-documented species for hosting the Leishmania species in Iran. Moreover, R. opimus has been found with a coinfection of Leishmania major and L. turanica from the northeast and center of Iran. Mashhad, Kerman, Yazd, and sometimes Shiraz and Tehran foci were distinct areas for L. tropica. Molecular identifications using genomic diagnosis of kDNA and ITS1 fragments of the parasite indicated that there is heterogeneity in leishmaniasis in different parts of the country. Although cutaneous leishmaniasis has been a predicament for the health system, it is relatively under control in Iran.
Topics: Animals; Humans; DNA, Kinetoplast; Iran; Disease Reservoirs; Zoonoses; Leishmaniasis, Cutaneous; Leishmania major; Gerbillinae
PubMed: 36269100
DOI: 10.1051/parasite/2022047 -
PLoS Neglected Tropical Diseases Apr 2021Zoonoses disproportionately affect tropical communities and are associated with human modification and use of ecosystems. Effective management is hampered by poor... (Review)
Review
Zoonoses disproportionately affect tropical communities and are associated with human modification and use of ecosystems. Effective management is hampered by poor ecological understanding of disease transmission and often focuses on human vaccination or treatment. Better ecological understanding of multi-vector and multi-host transmission, social and environmental factors altering human exposure, might enable a broader suite of management options. Options may include "ecological interventions" that target vectors or hosts and require good knowledge of underlying transmission processes, which may be more effective, economical, and long lasting than conventional approaches. New frameworks identify the hierarchical series of barriers that a pathogen needs to overcome before human spillover occurs and demonstrate how ecological interventions may strengthen these barriers and complement human-focused disease control. We extend these frameworks for vector-borne zoonoses, focusing on Kyasanur Forest Disease Virus (KFDV), a tick-borne, neglected zoonosis affecting poor forest communities in India, involving complex communities of tick and host species. We identify the hierarchical barriers to pathogen transmission targeted by existing management. We show that existing interventions mainly focus on human barriers (via personal protection and vaccination) or at barriers relating to Kyasanur Forest Disease (KFD) vectors (tick control on cattle and at the sites of host (monkey) deaths). We review the validity of existing management guidance for KFD through literature review and interviews with disease managers. Efficacy of interventions was difficult to quantify due to poor empirical understanding of KFDV-vector-host ecology, particularly the role of cattle and monkeys in the disease transmission cycle. Cattle are hypothesised to amplify tick populations. Monkeys may act as sentinels of human infection or are hypothesised to act as amplifying hosts for KFDV, but the spatial scale of risk arising from ticks infected via monkeys versus small mammal reservoirs is unclear. We identified 19 urgent research priorities for refinement of current management strategies or development of ecological interventions targeting vectors and host barriers to prevent disease spillover in the future.
Topics: Animals; Animals, Wild; Disease Reservoirs; Ecosystem; Encephalitis Viruses, Tick-Borne; India; Kyasanur Forest Disease; Mammals; Zoonoses
PubMed: 33793560
DOI: 10.1371/journal.pntd.0009243 -
FEMS Microbiology Reviews Nov 2019Avian influenza viruses (AIVs) continue to impose a negative impact on animal and human health worldwide. In particular, the emergence of highly pathogenic AIV H5 and,... (Review)
Review
Avian influenza viruses (AIVs) continue to impose a negative impact on animal and human health worldwide. In particular, the emergence of highly pathogenic AIV H5 and, more recently, the emergence of low pathogenic AIV H7N9 have led to enormous socioeconomical losses in the poultry industry and resulted in fatal human infections. While H5N1 remains infamous, the number of zoonotic infections with H7N9 has far surpassed those attributed to H5. Despite the clear public health concerns posed by AIV H7, it is unclear why specifically this virus subtype became endemic in poultry and emerged in humans. In this review, we bring together data on global patterns of H7 circulation, evolution and emergence in humans. Specifically, we discuss data from the wild bird reservoir, expansion and epidemiology in poultry, significant increase in their zoonotic potential since 2013 and genesis of highly pathogenic H7. In addition, we analysed available sequence data from an evolutionary perspective, demonstrating patterns of introductions into distinct geographic regions and reassortment dynamics. The integration of all aspects is crucial in the optimisation of surveillance efforts in wild birds, poultry and humans, and we emphasise the need for a One Health approach in controlling emerging viruses such as AIV H7.
Topics: Animals; Disease Reservoirs; Epidemiological Monitoring; Humans; Influenza A Virus, H7N9 Subtype; Influenza in Birds; Influenza, Human; One Health; Phylogeny; Poultry; Zoonoses
PubMed: 31381759
DOI: 10.1093/femsre/fuz019 -
Epidemiology and Infection Oct 2019Tularaemia is a zoonotic disease, in Europe caused by Francisella tularensis subsp. holarctica. Many lagomorphs and a variety of small rodents are wildlife species prone...
Tularaemia is a zoonotic disease, in Europe caused by Francisella tularensis subsp. holarctica. Many lagomorphs and a variety of small rodents are wildlife species prone to develop clinical disease, while predators and scavengers are relatively resistant and may serve as sentinels. Blood samples from 656 Swedish wild predators and scavengers were serologically investigated using slide agglutination and microagglutination. In the slide agglutination test, 34 seropositive animals were detected, and they were found among all species investigated: brown bear (Ursus arctos), Eurasian lynx (Lynx lynx), raccoon dog (Nyctereutes procyonoides), red fox (Vulpes vulpes), wild boar (Sus scrofa), wolf (Canis lupus) and wolverine (Gulo gulo). Due to haemolysis the microagglutination test was more difficult to read at low titres, and only 12 animals were classified as seropositive. F. tularensis subsp. holarctica was detected by a polymerase chain reaction in lymphatic tissues of the head in one brown bear, one red fox and one wolf. The significance of this finding regarding possible latency of infection is not clear. In conclusion, the results of this study indicate that all predator and scavenger species included in this study may serve as sentinels for tularaemia in Sweden. Their role as reservoirs is unclear.
Topics: Animals; Animals, Wild; Disease Reservoirs; Francisella tularensis; Predatory Behavior; Sentinel Species; Seroepidemiologic Studies; Sweden; Tularemia; Zoonoses
PubMed: 31637994
DOI: 10.1017/S0950268819001808 -
Proceedings of the National Academy of... Apr 2020Bats are reservoirs of emerging viruses that are highly pathogenic to other mammals, including humans. Despite the diversity and abundance of bat viruses, to date they...
Bats are reservoirs of emerging viruses that are highly pathogenic to other mammals, including humans. Despite the diversity and abundance of bat viruses, to date they have not been shown to harbor exogenous retroviruses. Here we report the discovery and characterization of a group of koala retrovirus-related (KoRV-related) gammaretroviruses in Australian and Asian bats. These include the Hervey pteropid gammaretrovirus (HPG), identified in the scat of the Australian black flying fox (), which is the first reproduction-competent retrovirus found in bats. HPG is a close relative of KoRV and the gibbon ape leukemia virus (GALV), with virion morphology and Mn-dependent virion-associated reverse transcriptase activity typical of a gammaretrovirus. In vitro, HPG is capable of infecting bat and human cells, but not mouse cells, and displays a similar pattern of cell tropism as KoRV-A and GALV. Population studies reveal the presence of HPG and KoRV-related sequences in several locations across northeast Australia, as well as serologic evidence for HPG in multiple pteropid bat species, while phylogenetic analysis places these bat viruses as the basal group within the KoRV-related retroviruses. Taken together, these results reveal bats to be important reservoirs of exogenous KoRV-related gammaretroviruses.
Topics: Animals; Australia; Chiroptera; Disease Reservoirs; Gammaretrovirus; Phascolarctidae
PubMed: 32284399
DOI: 10.1073/pnas.1915400117 -
Veterinary Research Feb 2021Animal tuberculosis (TB) is a multi-host disease caused by members of the Mycobacterium tuberculosis complex (MTC). Due to its impact on economy, sanitary standards of...
Animal tuberculosis (TB) is a multi-host disease caused by members of the Mycobacterium tuberculosis complex (MTC). Due to its impact on economy, sanitary standards of milk and meat industry, public health and conservation, TB control is an actively ongoing research subject. Several wildlife species are involved in the maintenance and transmission of TB, so that new approaches to wildlife TB diagnosis have gained relevance in recent years. Diagnosis is a paramount step for screening, epidemiological investigation, as well as for ensuring the success of control strategies such as vaccination trials. This is the first review that systematically addresses data available for the diagnosis of TB in wildlife following the Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The article also gives an overview of the factors related to host, environment, sampling, and diagnostic techniques which can affect test performance. After three screenings, 124 articles were considered for systematic review. Literature indicates that post-mortem examination and culture are useful methods for disease surveillance, but immunological diagnostic tests based on cellular and humoral immune response detection are gaining importance in wildlife TB diagnosis. Among them, serological tests are especially useful in wildlife because they are relatively inexpensive and easy to perform, facilitate large-scale surveillance and can be used both ante- and post-mortem. Currently available studies assessed test performance mostly in cervids, European badgers, wild suids and wild bovids. Research to improve diagnostic tests for wildlife TB diagnosis is still needed in order to reach accurate, rapid and cost-effective diagnostic techniques adequate to a broad range of target species and consistent over space and time to allow proper disease monitoring.
Topics: Animals; Animals, Wild; Disease Reservoirs; Mycobacterium bovis; Mycobacterium tuberculosis; Tuberculosis
PubMed: 33627188
DOI: 10.1186/s13567-020-00881-y -
Revista Chilena de Pediatria Oct 2020
Topics: Breast; Cytomegalovirus; Disease Reservoirs; Female; HIV-1; Hepatitis Viruses; Human T-lymphotropic virus 1; Humans; Infant, Newborn; Listeria; Milk, Human; SARS-CoV-2; Streptococcus agalactiae
PubMed: 33399629
DOI: 10.32641/rchped.vi91i5.3079 -
Viruses Oct 2020Hepatitis E virus (HEV) (family ) is one of the most common human pathogens, causing acute hepatitis and an increasingly recognized etiological agent in chronic... (Review)
Review
Hepatitis E virus (HEV) (family ) is one of the most common human pathogens, causing acute hepatitis and an increasingly recognized etiological agent in chronic hepatitis and extrahepatic manifestations. Recent studies reported that not only are the classical members of the species (HEV-A) pathogenic to humans but a genetically highly divergent rat origin hepevirus (HEV-C1) in species (HEV-C) is also able to cause zoonotic infection and symptomatic disease (hepatitis) in humans. This review summarizes the current knowledge of hepeviruses in rodents with special focus of rat origin HEV-C1. Cross-species transmission and genetic diversity of HEV-C1 and confirmation of HEV-C1 infections and symptomatic disease in humans re-opened the long-lasting and full of surprises story of HEV in human. This novel knowledge has a consequence to the epidemiology, clinical aspects, laboratory diagnosis, and prevention of HEV infection in humans.
Topics: Animals; Cell Line; Disease Reservoirs; Genome, Viral; Hepatitis E; Hepatitis E virus; Hepatitis, Viral, Animal; Hepevirus; Humans; Phylogeny; Rats; Zoonoses
PubMed: 33050353
DOI: 10.3390/v12101148