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Philosophical Transactions of the Royal... Sep 2019The risk of zoonotic spillover from reservoir hosts, such as wildlife or domestic livestock, to people is shaped by the spatial and temporal distribution of infection in... (Review)
Review
The risk of zoonotic spillover from reservoir hosts, such as wildlife or domestic livestock, to people is shaped by the spatial and temporal distribution of infection in reservoir populations. Quantifying these distributions is a key challenge in epidemiology and disease ecology that requires researchers to make trade-offs between the extent and intensity of spatial versus temporal sampling. We discuss sampling methods that strengthen the reliability and validity of inferences about the dynamics of zoonotic pathogens in wildlife hosts. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'.
Topics: Animals; Animals, Wild; Disease Reservoirs; Epidemiological Monitoring; Population Surveillance; Reproducibility of Results; Zoonoses
PubMed: 31401966
DOI: 10.1098/rstb.2018.0336 -
Viruses Feb 2021Mosquito-borne viruses are well recognized as a global public health burden amongst humans, but the effects on non-human vertebrates is rarely reported. Australia,... (Review)
Review
Mosquito-borne viruses are well recognized as a global public health burden amongst humans, but the effects on non-human vertebrates is rarely reported. Australia, houses a number of endemic mosquito-borne viruses, such as Ross River virus, Barmah Forest virus, and Murray Valley encephalitis virus. In this review, we synthesize the current state of mosquito-borne viruses impacting non-human vertebrates in Australia, including diseases that could be introduced due to local mosquito distribution. Given the unique island biogeography of Australia and the endemism of vertebrate species (including macropods and monotremes), Australia is highly susceptible to foreign mosquito species becoming established, and mosquito-borne viruses becoming endemic alongside novel reservoirs. For each virus, we summarize the known geographic distribution, mosquito vectors, vertebrate hosts, clinical signs and treatments, and highlight the importance of including non-human vertebrates in the assessment of future disease outbreaks. The mosquito-borne viruses discussed can impact wildlife, livestock, and companion animals, causing significant changes to Australian ecology and economy. The complex nature of mosquito-borne disease, and challenges in assessing the impacts to non-human vertebrate species, makes this an important topic to periodically review.
Topics: Alphavirus; Alphavirus Infections; Animals; Animals, Wild; Australia; Culicidae; Disease Outbreaks; Disease Reservoirs; Encephalitis Virus, Murray Valley; Encephalitis, Arbovirus; Humans; Livestock; Mosquito Vectors; Pets; Public Health; Ross River virus
PubMed: 33572234
DOI: 10.3390/v13020265 -
Applied Microbiology and Biotechnology Feb 2021Bats as flying mammals are potent vectors and natural reservoir hosts for many infectious viruses, bacteria, and fungi, also detected in their excreta such as guano....
Bats as flying mammals are potent vectors and natural reservoir hosts for many infectious viruses, bacteria, and fungi, also detected in their excreta such as guano. Accelerated deforestation, urbanization, and anthropization hastily lead to overpopulation of the bats in urban areas allowing easy interaction with other animals, expansion, and emergence of new zoonotic disease outbreaks potentially harmful to humans. Therefore, getting new insights in the microbiome of bat guano from different places represents an imperative for the future. Furthermore, the use of novel high-throughput sequencing technologies allows better insight in guano microbiome and potentially indicated that some species could be typical guano-dwelling members. Bats are well known as a natural reservoir of many zoonotic viruses such as Ebola, Nipah, Marburg, lyssaviruses, rabies, henipaviruses, and many coronaviruses which caused a high number of outbreaks including ongoing COVID-19 pandemic. Additionally, many bacterial and fungal pathogens were identified as common guano residents. Thus, the presence of multi-drug-resistant bacteria as environmental reservoirs of extended spectrum β-lactamases and carbapenemase-producing strains has been confirmed. Bat guano is the most suitable substrate for fungal reproduction and dissemination, including pathogenic yeasts and keratinophilic and dimorphic human pathogenic fungi known as notorious causative agents of severe endemic mycoses like histoplasmosis and fatal cryptococcosis, especially deadly in immunocompromised individuals. This review provides an overview of bat guano microbiota diversity and the significance of autochthonous and pathogenic taxa for humans and the environment, highlighting better understanding in preventing emerging diseases. KEY POINTS: Bat guano as reservoir and source for spreading of autochthonous and pathogenic microbiota Bat guano vs. novel zoonotic disease outbreaks Destruction of bat natural habitats urgently demands increased human awareness.
Topics: Animals; Biodiversity; Chiroptera; Communicable Diseases, Emerging; Conservation of Natural Resources; Disease Reservoirs; Feces; Humans; Microbiota
PubMed: 33512572
DOI: 10.1007/s00253-021-11143-y -
Current Opinion in Plant Biology Aug 2020Understanding the ecological and evolutionary processes underlying the emergence of infectious disease is critically important in guiding prevention, management and... (Review)
Review
Understanding the ecological and evolutionary processes underlying the emergence of infectious disease is critically important in guiding prevention, management and breeding strategies. Novel pathogen lineages may arise within agricultural environments, wild hosts or from non-host associated disease reservoirs. Although the source of most disease outbreaks remains unknown, environmental and zoonotic origins are frequently identified in mammalian pathosystems and expanded sampling of plant pathosystems reveals important links with wild populations. This review describes key ecological and evolutionary processes underlying disease emergence, with particular emphasis on shifts from wild reservoirs to cultivated hosts and genetic mechanisms driving host adaption subsequent to emergence.
Topics: Agriculture; Animals; Biological Evolution; Disease Reservoirs; Plant Diseases
PubMed: 32712539
DOI: 10.1016/j.pbi.2020.06.003 -
PLoS Neglected Tropical Diseases Aug 2020Yersinia pestis, the bacterial causative agent of plague, remains an important threat to human health. Plague is a rodent-borne disease that has historically shown an... (Review)
Review
Yersinia pestis, the bacterial causative agent of plague, remains an important threat to human health. Plague is a rodent-borne disease that has historically shown an outstanding ability to colonize and persist across different species, habitats, and environments while provoking sporadic cases, outbreaks, and deadly global epidemics among humans. Between September and November 2017, an outbreak of urban pneumonic plague was declared in Madagascar, which refocused the attention of the scientific community on this ancient human scourge. Given recent trends and plague's resilience to control in the wild, its high fatality rate in humans without early treatment, and its capacity to disrupt social and healthcare systems, human plague should be considered as a neglected threat. A workshop was held in Paris in July 2018 to review current knowledge about plague and to identify the scientific research priorities to eradicate plague as a human threat. It was concluded that an urgent commitment is needed to develop and fund a strong research agenda aiming to fill the current knowledge gaps structured around 4 main axes: (i) an improved understanding of the ecological interactions among the reservoir, vector, pathogen, and environment; (ii) human and societal responses; (iii) improved diagnostic tools and case management; and (iv) vaccine development. These axes should be cross-cutting, translational, and focused on delivering context-specific strategies. Results of this research should feed a global control and prevention strategy within a "One Health" approach.
Topics: Animals; Disease Outbreaks; Disease Reservoirs; Humans; Insect Vectors; Madagascar; Neglected Diseases; Plague; Rodentia; Siphonaptera; Yersinia pestis
PubMed: 32853251
DOI: 10.1371/journal.pntd.0008251 -
Viruses Jul 2019Tick-borne encephalitis virus (TBEV) is an important arbovirus, which is found across large parts of Eurasia and is considered to be a major health risk for humans. Like... (Review)
Review
Tick-borne encephalitis virus (TBEV) is an important arbovirus, which is found across large parts of Eurasia and is considered to be a major health risk for humans. Like any other arbovirus, TBEV relies on complex interactions between vectors, reservoir hosts, and the environment for successful virus circulation. Hard ticks are the vectors for TBEV, transmitting the virus to a variety of animals. The importance of these animals in the lifecycle of TBEV is still up for debate. Large woodland animals seem to have a positive influence on virus circulation by providing a food source for adult ticks; birds are suspected to play a role in virus distribution. Bank voles and yellow-necked mice are often referred to as classical virus reservoirs, but this statement lacks strong evidence supporting their highlighted role. Other small mammals (e.g., insectivores) may also play a crucial role in virus transmission, not to mention the absence of any suspected reservoir host for non-European endemic regions. Theories highlighting the importance of the co-feeding transmission route go as far as naming ticks themselves as the true reservoir for TBEV, and mammalian hosts as a mere bridge for transmission. A deeper insight into the virus reservoir could lead to a better understanding of the development of endemic regions. The spatial distribution of TBEV is constricted to certain areas, forming natural foci that can be restricted to sizes of merely 500 square meters. The limiting factors for their occurrence are largely unknown, but a possible influence of reservoir hosts on the distribution pattern of TBE is discussed. This review aims to give an overview of the multiple factors influencing the TBEV transmission cycle, focusing on the role of virus reservoirs, and highlights the questions that are waiting to be further explored.
Topics: Animals; Animals, Wild; Disease Reservoirs; Encephalitis Viruses, Tick-Borne; Encephalitis, Tick-Borne; Humans; Insect Vectors; Ixodes; Mammals; Prevalence
PubMed: 31336624
DOI: 10.3390/v11070669 -
Viruses Nov 2021Zoonotic infections of humans with influenza A viruses (IAVs) from animal reservoirs can result in severe disease in individuals and, in rare cases, lead to pandemic... (Review)
Review
Zoonotic infections of humans with influenza A viruses (IAVs) from animal reservoirs can result in severe disease in individuals and, in rare cases, lead to pandemic outbreaks; this is exemplified by numerous cases of human infection with avian IAVs (AIVs) and the 2009 swine influenza pandemic. In fact, zoonotic transmissions are strongly facilitated by manmade reservoirs that were created through the intensification and industrialization of livestock farming. This can be witnessed by the repeated introduction of IAVs from natural reservoirs of aquatic wild bird metapopulations into swine and poultry, and the accompanied emergence of partially- or fully-adapted human pathogenic viruses. On the other side, human adapted IAV have been (and still are) introduced into livestock by reverse zoonotic transmission. This link to manmade reservoirs was also observed before the 20th century, when horses seemed to have been an important reservoir for IAVs but lost relevance when the populations declined due to increasing industrialization. Therefore, to reduce zoonotic events, it is important to control the spread of IAV within these animal reservoirs, for example with efficient vaccination strategies, but also to critically surveil the different manmade reservoirs to evaluate the emergence of new IAV strains with pandemic potential.
Topics: Agriculture; Animals; Birds; Disease Reservoirs; Humans; Influenza A virus; Mammals; Orthomyxoviridae Infections; Pandemics; Viral Zoonoses
PubMed: 34835056
DOI: 10.3390/v13112250 -
Journal of Helminthology Aug 2019Dracunculiasis is the first parasitic disease set for eradication. However, recent events related to the Dracunculus medinensis epidemiology in certain African countries... (Review)
Review
Dracunculiasis is the first parasitic disease set for eradication. However, recent events related to the Dracunculus medinensis epidemiology in certain African countries are apparently posing new challenges to its eradication. Two novel facts have emerged: the existence of animal reservoirs (mainly dogs but also cats and baboons), and possibly a new food-borne route of transmission by the ingestion of paratenic (frogs) or transport (fish) hosts. Therefore, instead of being exclusively a water-borne anthroponosis, dracunculiasis would also be a food-borne zoonosis. The existence of a large number of infected dogs, mainly in Chad, and the low number of infected humans, have given rise to this potential food-borne transmission. This novel route would concern not only reservoirs, but also humans. However, only animals seem to be affected. Dracunculus medinensis is on the verge of eradication due to the control measures which, classically, have been exclusively aimed at the water-borne route. Therefore, food-borne transmission is probably of secondary importance, at least in humans. In Chad, reservoirs would become infected through the water-borne route, mainly in the dry season when rivers recede, and smaller accessible ponds, with a lower water level containing the infected copepods, appear, whilst humans drink filtered water and, thus, avoid infection. The total absence of control measures aimed at dogs (or at other potential reservoirs) up until the last years, added to the stimulating reward in cash given to those who find parasitized dogs, have presumably given rise to the current dracunculiasis scenario in Chad.
Topics: Africa; Animals; Cats; Chad; Copepoda; Disease Eradication; Disease Reservoirs; Dogs; Dracunculiasis; Foodborne Diseases; Humans; Water; Zoonoses
PubMed: 31434586
DOI: 10.1017/S0022149X19000713 -
Chemotherapy 2021Viruses arise through cross-species transmission and can cause potentially fatal diseases in humans. This is the case of the severe acute respiratory syndrome... (Review)
Review
Viruses arise through cross-species transmission and can cause potentially fatal diseases in humans. This is the case of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which recently appeared in Wuhan, China, and rapidly spread worldwide, causing the outbreak of coronavirus disease 2019 (COVID-19) and posing a global health emergency. Sequence analysis and epidemiological investigations suggest that the most likely original source of SARS-CoV-2 is a spillover from an animal reservoir, probably bats, that infected humans either directly or through intermediate animal hosts. The role of animals as reservoirs and natural hosts in SARS-CoV-2 has to be explored, and animal models for COVID-19 are needed as well to be evaluated for countermeasures against SARS-CoV-2 infection. Experimental cells, tissues, and animal models that are currently being used and developed in COVID-19 research will be presented.
Topics: Animals; COVID-19; Communicable Disease Control; Disease Reservoirs; Disease Transmission, Infectious; Disease Vectors; Humans; Models, Theoretical; SARS-CoV-2
PubMed: 33774628
DOI: 10.1159/000515341 -
Viruses May 2021The persistence of HIV-1 viral reservoirs in the brain, despite treatment with combination antiretroviral therapy (cART), remains a critical roadblock for the...
The persistence of HIV-1 viral reservoirs in the brain, despite treatment with combination antiretroviral therapy (cART), remains a critical roadblock for the development of a novel cure strategy for HIV-1. To enhance our understanding of viral reservoirs, two complementary studies were conducted to (1) evaluate the HIV-1 mRNA distribution pattern and major cell type expressing HIV-1 mRNA in the HIV-1 transgenic (Tg) rat, and (2) validate our findings by developing and critically testing a novel biological system to model active HIV-1 infection in the rat. First, a restricted, region-specific HIV-1 mRNA distribution pattern was observed in the HIV-1 Tg rat. Microglia were the predominant cell type expressing HIV-1 mRNA in the HIV-1 Tg rat. Second, we developed and critically tested a novel biological system to model key aspects of HIV-1 by infusing F344/N control rats with chimeric HIV (EcoHIV). In vitro, primary cultured microglia were treated with EcoHIV revealing prominent expression within 24 h of infection. In vivo, EcoHIV expression was observed seven days after stereotaxic injections. Following EcoHIV infection, microglia were the major cell type expressing HIV-1 mRNA, results that are consistent with observations in the HIV-1 Tg rat. Within eight weeks of infection, EcoHIV rats exhibited neurocognitive impairments and synaptic dysfunction, which may result from activation of the NogoA-NgR3/PirB-RhoA signaling pathway and/or neuroinflammation. Collectively, these studies enhance our understanding of HIV-1 viral reservoirs in the brain and offer a novel biological system to model HIV-associated neurocognitive disorders and associated comorbidities (i.e., drug abuse) in rats.
Topics: Animals; Cells, Cultured; Disease Models, Animal; Disease Reservoirs; Female; HIV-1; Male; Microglia; Neurocognitive Disorders; Neuroinflammatory Diseases; RNA, Viral; Rats; Rats, Inbred F344; Rats, Transgenic
PubMed: 34067600
DOI: 10.3390/v13050924