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Ticks and Tick-borne Diseases Jul 2021The literature on Lyme disease includes a lively debate about the paradoxical role of changing deer populations. A decrease in the number of deer will both (1) reduce...
The literature on Lyme disease includes a lively debate about the paradoxical role of changing deer populations. A decrease in the number of deer will both (1) reduce the incidence of Lyme disease by decreasing the host populations for ticks and therefore tick populations, and (2) enhance the incidence of Lyme disease by offering fewer reservoir-incompetent hosts for ticks, forcing the vector to choose reservoir-competent, and therefore possibly diseased, hosts to feed on. A review of field studies exploring the net impact of changing deer populations shows mixed results. In this manuscript, we investigate the hypothesis that the balance of these two responses to changing deer populations depends on the relative population sizes of reservoir-competent vs. reservoir-incompetent hosts and the presence of host preference in larval and adult stages. A temperature driven seasonal model of Borrelia burgdorferi sensu stricto (cause of Lyme disease) transmission among three host types (reservoir-competent infected and uninfected hosts, and reservoir-incompetent hosts) is constructed as a system of nonlinear ordinary differential equations. The model, which produces biologically reasonable results for both the tick vector Ixodes scapularis Say 1921 and the hosts, is used to investigate the effects of reservoir-incompetent host removal on both tick populations and disease prevalence for various relative population sizes of reservoir-competent hosts vs. reservoir-incompetent hosts. In summary, the simulation results show that the model with host preference appears to be more accurate than the one with no host preference. Given these results, we found that removal of adult I. scapularis(Say) hosts is likely to reduce questing nymph populations. At very low levels questing adult abundance may rise with lack of adult hosts. There is a dilution effect at low reservoir-competent host populations and there is an amplification effect at high reservoir-competent host populations.
Topics: Animals; Borrelia burgdorferi; Disease Reservoirs; Disease Vectors; Ixodes; Larva; Lyme Disease; Models, Biological; Nymph
PubMed: 33878571
DOI: 10.1016/j.ttbdis.2021.101724 -
EcoHealth Dec 2017We examine Zika virus (ZIKV) from an ecological perspective and with a focus on the Americas. We assess (1) the role of wildlife in ZIKV disease ecology, (2) how... (Review)
Review
We examine Zika virus (ZIKV) from an ecological perspective and with a focus on the Americas. We assess (1) the role of wildlife in ZIKV disease ecology, (2) how mosquito behavior and biology influence disease dynamics, and (3) how nontarget species and ecosystems may be impacted by vector control programs. Our review suggests that free-ranging, non-human primates may be involved in ZIKV transmission in the Old World; however, other wildlife species likely play a limited role in maintaining or transmitting ZIKV. In the Americas, a zoonotic cycle has not yet been definitively established. Understanding behaviors and habitat tolerances of Aedes aegypti and Aedes albopictus, two ZIKV competent vectors in the Americas, will allow more accurate modeling of disease spread and facilitate targeted and effective control efforts. Vector control efforts may have direct and indirect impacts to wildlife, particularly invertebrate feeding species; however, strategies could be implemented to limit detrimental ecological effects.
Topics: Aedes; Americas; Animals; Animals, Wild; Communicable Disease Control; Disease Reservoirs; Ecosystem; Mosquito Vectors; Zika Virus; Zoonoses
PubMed: 29150828
DOI: 10.1007/s10393-017-1277-2 -
Current Opinion in Virology Feb 2019Hepatitis E virus (HEV) infects both humans and other animal species. Recently, we have seen a steady increase in autochthonous cases of human HEV infection in certain... (Review)
Review
Hepatitis E virus (HEV) infects both humans and other animal species. Recently, we have seen a steady increase in autochthonous cases of human HEV infection in certain areas especially in Europe, and large outbreaks in several African countries among the displaced population. This mini-review critically analyzes potential host, environmental, and viral factors that may be associated with the emergence of hepatitis E in humans. The existence of numerous HEV reservoir animals such as pig, deer and rabbit results in human exposure to infected animals via direct contact or through animal meat consumption. Contamination of drinking, irrigation and coastal water by animal and human wastes lead to emergence of endemic cases in industrialized countries and outbreaks in displaced communities especially in war-torn countries.
Topics: Animals; Communicable Diseases, Emerging; Disease Outbreaks; Disease Reservoirs; Hepatitis E; Hepatitis E virus; Humans; Meat; Point Mutation; Recombination, Genetic; Swine; Zoonoses
PubMed: 30497051
DOI: 10.1016/j.coviro.2018.11.006 -
Proceedings of the National Academy of... Mar 2020Disease outbreaks and pathogen introductions can have significant effects on host populations, and the ability of pathogens to persist in the environment can exacerbate...
Disease outbreaks and pathogen introductions can have significant effects on host populations, and the ability of pathogens to persist in the environment can exacerbate disease impacts by fueling sustained transmission, seasonal epidemics, and repeated spillover events. While theory suggests that the presence of an environmental reservoir increases the risk of host declines and threat of extinction, the influence of reservoir dynamics on transmission and population impacts remains poorly described. Here we show that the extent of the environmental reservoir explains broad patterns of host infection and the severity of disease impacts of a virulent pathogen. We examined reservoir and host infection dynamics and the resulting impacts of , the fungal pathogen that causes white-nose syndrome, in 39 species of bats at 101 sites across the globe. Lower levels of pathogen in the environment consistently corresponded to delayed infection of hosts, fewer and less severe infections, and reduced population impacts. In contrast, an extensive and persistent environmental reservoir led to early and widespread infections and severe population declines. These results suggest that continental differences in the persistence or decay of in the environment altered infection patterns in bats and influenced whether host populations were stable or experienced severe declines from this disease. Quantifying the impact of the environmental reservoir on disease dynamics can provide specific targets for reducing pathogen levels in the environment to prevent or control future epidemics.
Topics: Animals; Ascomycota; Chiroptera; Disease Reservoirs; Epidemics; Hibernation; Mycoses; Nose; Nose Diseases; Population Dynamics; Seasons
PubMed: 32179668
DOI: 10.1073/pnas.1914794117 -
Tropical Medicine & International... Sep 2023To analyse acute Chagas disease (CD) outbreaks through a qualitative systematic review and discuss the determinants for its prevention and control.
OBJECTIVE
To analyse acute Chagas disease (CD) outbreaks through a qualitative systematic review and discuss the determinants for its prevention and control.
METHODS
Review of studies in which clinical cases of oral transmission were confirmed by parasitological and/or serological tests that included an epidemiological investigation of sources of infection, vectors and reservoirs.
RESULTS
Thirty-two outbreaks (1965-2022) were analysed. The main foods involved in oral transmission outbreaks are homemade fruit juices. Different species of vectors were identified. Reservoirs were mainly dogs, rodents and large American opossums (didelphids).
CONCLUSION
Under a One Health approach, environmental changes are one of the factors responsible of the rise of oral transmission of CD. Entomological surveillance of vectors and control of the changes in wild and domestic reservoirs and reinforcement of hygiene measures around food in domestic and commercial sites are needed.
Topics: Animals; Dogs; Chagas Disease; Disease Reservoirs; Genotype; One Health; Opossums; Trypanosoma cruzi
PubMed: 37488635
DOI: 10.1111/tmi.13915 -
The Journal of General Virology Aug 2017Infection with feline immunodeficiency virus (FIV), a lentivirus similar to human immunodeficiency virus (HIV), results in lifelong viral persistence and progressive... (Review)
Review
Infection with feline immunodeficiency virus (FIV), a lentivirus similar to human immunodeficiency virus (HIV), results in lifelong viral persistence and progressive immunopathology in the cat. FIV has the ability to infect and produce infectious virus in a number of different cell types. FIV provirus can also be maintained in a replication-competent but transcriptionally quiescent state, facilitating viral persistence over time. Immediately after the initial infection, FIV infection quickly disseminates to many anatomical compartments within the host including lymphoid organs, gastrointestinal tract and brain. Collectively, the anatomic and cellular compartments that harbour FIV provirus constitute the viral reservoir and contain foci of both ongoing viral replication and transcriptionally restricted virus that may persist over time. The relative importance of the different phenotypes observed for infected cells, anatomic compartment, replication status and size of the reservoir represent crucial areas of investigation for developing effective viral suppression and eradication therapies. In this review, we discuss what is currently known about FIV reservoirs, and emphasize the utility of the FIV-infected cat as a model for the HIV-infected human.
Topics: Animal Structures; Animals; Cats; Disease Reservoirs; Feline Acquired Immunodeficiency Syndrome; Immunodeficiency Virus, Feline; Virus Replication
PubMed: 28749325
DOI: 10.1099/jgv.0.000866 -
Integrative Zoology Nov 2021Plague has been known since ancient times as a re-emerging infectious disease, causing considerable socioeconomic burden in regional hotspots. To better understand the...
Plague has been known since ancient times as a re-emerging infectious disease, causing considerable socioeconomic burden in regional hotspots. To better understand the epidemiological cycle of the causative agent of the plague, its potential occurrence, and possible future dispersion, one must carefully consider the taxonomy, distribution, and ecological requirements of reservoir-species in relation either to natural or human-driven changes (e.g. climate change or urbanization). In recent years, the depth of knowledge on species taxonomy and species composition in different landscapes has undergone a dramatic expansion, driven by modern taxonomic methods such as synthetic surveys that take into consideration morphology, genetics, and the ecological setting of captured animals to establish their species identities. Here, we consider the recent taxonomic changes of the rodent species in known plague reservoirs and detail their distribution across the world, with a particular focus on those rodents considered to be keystone host species. A complete checklist of all known plague-infectable vertebrates living in plague foci is provided as a Supporting Information table.
Topics: Animal Distribution; Animals; Disease Reservoirs; Global Health; Plague; Rodentia; Yersinia pestis
PubMed: 33264458
DOI: 10.1111/1749-4877.12511 -
Current Opinion in HIV and AIDS Sep 2018A number studies are currently underway to develop new drugs aimed at reducing the HIV reservoir or achieving ART-free control of HIV infection. Many markers of HIV... (Review)
Review
PURPOSE OF REVIEW
A number studies are currently underway to develop new drugs aimed at reducing the HIV reservoir or achieving ART-free control of HIV infection. Many markers of HIV reservoirs have been proposed, each one having a different meaning. Total HIV DNA dynamics during the course of HIV infection and its predictive value are now well known. This marker allowed to estimate the size of HIV reservoir at different stages of HIV infection in blood, cell subsets and tissues. Therefore, the purpose of this review is timely and relevant, with the objective to discuss how total HIV DNA might be helpful in the clinical settings.
RECENT FINDINGS
Among the markers, it appears that HIV DNA is the most well studied, and recent articles confirmed that this marker is easy to use and is precise, specific, practical, robust and reproducible. All these characteristics correspond to what is expected from a helpful clinical marker.
SUMMARY
HIV DNA level could be considered as a global marker, and it is usually included in current clinical studies to describe the persistence and dynamics of the HIV reservoir, mainly in treated patients. HIV DNA might be helpful in designing clinical trials and personalized medication for HIV patients in the future.
Topics: Animals; Biomarkers; DNA, Viral; Disease Reservoirs; HIV Infections; HIV-1; Humans; Virus Latency
PubMed: 30020275
DOI: 10.1097/COH.0000000000000483 -
Journal of Immunology (Baltimore, Md. :... Oct 2023Bovine tuberculosis (bTB) is a zoonotic bacterial disease presenting public health, veterinary, and economic threats around the globe. Although cattle producers rely on... (Review)
Review
Bovine tuberculosis (bTB) is a zoonotic bacterial disease presenting public health, veterinary, and economic threats around the globe. Although cattle producers rely on regular testing and management practices to minimize domestic herd exposure, wildlife species around the world continue to be the main reservoirs for disease. Wildlife reservoirs for bTB include the Eurasian badger (Meles meles) in Great Britain and Ireland, the brushtail possum (Trichosurus vulpecula) in New Zealand, wild boar (Sus scrofa) in Spain, as well as white-tailed deer (Odocoileus virginianus) in the United States and red deer (Cervus elaphus) in Spain. Although all reservoir species share the ability to infect cattle, they differ in transmission capability, disease pathogenesis, diagnostic detection, and vaccination strategies. In this review, bTB interactions with these wildlife reservoirs are discussed, illustrating the need to address bTB disease in wildlife hosts to achieve eradication in domestic livestock.
Topics: Cattle; Animals; Mycobacterium bovis; Animals, Wild; Deer; Disease Reservoirs; Tuberculosis, Bovine
PubMed: 37782851
DOI: 10.4049/jimmunol.2300323 -
Current Topics in Microbiology and... 2023Individuals living in endemic hotspots of Lassa fever have recurrent exposure to Lassa virus (LASV) via spillover from the primary host reservoir Mastomys natalensis....
Individuals living in endemic hotspots of Lassa fever have recurrent exposure to Lassa virus (LASV) via spillover from the primary host reservoir Mastomys natalensis. Despite M. natalensis being broadly distributed across sub-Saharan Africa, Lassa fever is only found in West Africa. In recent years, new LASV reservoirs have been identified. Erudition of rodent habitats, reproduction and fecundity, movement patterns, and spatial preferences are essential to institute preventative measures against Lassa fever. Evolutionary insights have also added to our knowledge of closely related mammarenavirus distribution amongst rodents throughout the continent.
Topics: Animals; Lassa virus; Lassa Fever; Disease Reservoirs; Murinae
PubMed: 33564902
DOI: 10.1007/82_2020_231