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The Veterinary Quarterly Dec 2021Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, previously 2019-nCoV) is suspected of having originated in 2019 in China from a coronavirus infected bat of... (Review)
Review
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, previously 2019-nCoV) is suspected of having originated in 2019 in China from a coronavirus infected bat of the genus . Following the initial emergence, possibly facilitated by a mammalian bridge host, SARS-CoV-2 is currently transmitted across the globe via efficient human-to-human transmission. Results obtained from experimental studies indicate that animal species such as cats, ferrets, raccoon dogs, cynomolgus macaques, rhesus macaques, white-tailed deer, rabbits, Egyptian fruit bats, and Syrian hamsters are susceptible to SARS-CoV-2 infection, and that cat-to-cat and ferret-to-ferret transmission can take place via contact and air. However, natural infections of SARS-CoV-2 have been reported only in pet dogs and cats, tigers, lions, snow leopards, pumas, and gorillas at zoos, and farmed mink and ferrets. Even though human-to-animal spillover has been reported at several instances, SARS-CoV-2 transmission from animals-to-humans has only been reported from mink-to-humans in mink farms. Following the rapid transmission of SARS-CoV-2 within the mink population, a new mink-associated SARS-CoV-2 variant emerged that was identified in both humans and mink. The increasing reports of SARS-CoV-2 in carnivores indicate the higher susceptibility of animal species belonging to this order. The sporadic reports of SARS-CoV-2 infection in domestic and wild animal species require further investigation to determine if SARS-CoV-2 or related Betacoronaviruses can get established in kept, feral or wild animal populations, which may eventually act as viral reservoirs. This review analyzes the current evidence of SARS-CoV-2 natural infection in domestic and wild animal species and their possible implications on public health.
Topics: Animals; Animals, Domestic; Animals, Wild; Animals, Zoo; COVID-19; Disease Reservoirs; Humans; Public Health; SARS-CoV-2
PubMed: 33892621
DOI: 10.1080/01652176.2021.1921311 -
Applied and Environmental Microbiology Aug 2021Bats are a key reservoir of coronaviruses (CoVs), including the agent of the severe acute respiratory syndrome, SARS-CoV-2, responsible for the recent deadly viral... (Review)
Review
Bats are a key reservoir of coronaviruses (CoVs), including the agent of the severe acute respiratory syndrome, SARS-CoV-2, responsible for the recent deadly viral pneumonia pandemic. However, understanding how bats can harbor several microorganisms without developing illnesses is still a matter under discussion. Viruses and other pathogens are often studied as stand-alone entities, despite that, in nature, they mostly live in multispecies associations called biofilms-both externally and within the host. Microorganisms in biofilms are enclosed by an extracellular matrix that confers protection and improves survival. Previous studies have shown that viruses can secondarily colonize preexisting biofilms, and viral biofilms have also been described. In this review, we raise the perspective that CoVs can persistently infect bats due to their association with biofilm structures. This phenomenon potentially provides an optimal environment for nonpathogenic and well-adapted viruses to interact with the host, as well as for viral recombination. Biofilms can also enhance virion viability in extracellular environments, such as on fomites and in aquatic sediments, allowing viral persistence and dissemination. Moreover, understanding the biofilm lifestyle of CoVs in reservoirs might contribute to explaining several burning questions as to persistence and transmissibility of highly pathogenic emerging CoVs.
Topics: Animals; Biofilms; COVID-19; Chiroptera; Disease Reservoirs; Humans; Pneumonia, Viral; SARS-CoV-2
PubMed: 34190608
DOI: 10.1128/AEM.00859-21 -
Viruses Sep 2020Rabies transmitted by common vampire bats () has been known since the early 1900s but continues to expand geographically and in the range of species and environments... (Review)
Review
Rabies transmitted by common vampire bats () has been known since the early 1900s but continues to expand geographically and in the range of species and environments affected. In this review, we present current knowledge of the epidemiology and management of rabies in and argue that it can be reasonably considered an emerging public health threat. We identify knowledge gaps related to the landscape determinants of the bat reservoir, reduction in bites on humans and livestock, and social barriers to prevention. We discuss how new technologies including autonomously-spreading vaccines and reproductive suppressants targeting bats might manage both rabies and undesirable growth of populations. Finally, we highlight widespread under-reporting of human and animal mortality and the scarcity of studies that quantify the efficacy of control measures such as bat culling. Collaborations between researchers and managers will be crucial to implement the next generation of rabies management in Latin America.
Topics: Animals; Chiroptera; Disease Reservoirs; Humans; Latin America; Rabies; Rabies virus
PubMed: 32911766
DOI: 10.3390/v12091002 -
Parasites & Vectors Jan 2022Leishmaniasis is endemic in Tunisia and presents with different clinical forms, caused by the species Leishmania infantum, Leishmania major, and Leishmania tropica. The...
BACKGROUND
Leishmaniasis is endemic in Tunisia and presents with different clinical forms, caused by the species Leishmania infantum, Leishmania major, and Leishmania tropica. The life cycle of Leishmania is complex and involves several phlebotomine sand fly vectors and mammalian reservoir hosts. The aim of this work is the development and evaluation of a high-resolution melting PCR (PCR-HRM) tool to detect and identify Leishmania parasites in wild and domestic hosts, constituting confirmed (dogs and Meriones rodents) or potential (hedgehogs) reservoirs in Tunisia.
METHODS
Using in vitro-cultured Leishmania isolates, PCR-HRM reactions were developed targeting the 7SL RNA and HSP70 genes. Animals were captured or sampled in El Kef Governorate, North West Tunisia. DNA was extracted from the liver, spleen, kidney, and heart from hedgehogs (Atelerix algirus) (n = 3) and rodents (Meriones shawi) (n = 7) and from whole blood of dogs (n = 12) that did not present any symptoms of canine leishmaniasis. In total, 52 DNA samples were processed by PCR-HRM using both pairs of primers.
RESULTS
The results showed melting curves enabling discrimination of the three Leishmania species present in Tunisia, and were further confirmed by Sanger sequencing. Application of PCR-HRM assays on reservoir host samples showed that overall among the examined samples, 45 were positive, while seven were negative, with no Leishmania infection. Meriones shawi were found infected with L. major, while dogs were infected with L. infantum. However, co-infections with L. major/L. infantum species were detected in four Meriones specimens and in all tested hedgehogs. In addition, multiple infections with the three Leishmania species were found in one hedgehog specimen. Sequence analyses of PCR-HRM products corroborated the Leishmania species found in analyzed samples.
CONCLUSIONS
The results of PCR-HRM assays applied to field specimens further support the possibility of hedgehogs as reservoir hosts of Leishmania. In addition, we showed their usefulness in the diagnosis of canine leishmaniasis, specifically in asymptomatic dogs, which will ensure a better evaluation of infection extent, thus improving elaboration of control programs. This PCR-HRM method is a robust and reliable tool for molecular detection and identification of Leishmania and can be easily implemented in epidemiological surveys in endemic regions.
Topics: Animals; Disease Reservoirs; Dogs; Endemic Diseases; Gerbillinae; Hedgehogs; Humans; Leishmania; Leishmaniasis; Polymerase Chain Reaction; Rodentia; Transition Temperature; Tunisia
PubMed: 34996507
DOI: 10.1186/s13071-021-05138-x -
The Veterinary Record Feb 2020
Topics: Animals; Betacoronavirus; COVID-19; Chiroptera; Coronavirus Infections; Disease Reservoirs; Humans; Pandemics; Pneumonia, Viral; SARS-CoV-2; Zoonoses
PubMed: 32108071
DOI: 10.1136/vr.m740 -
Cells Feb 2021Eradication of latent human immunodeficiency virus (HIV) infection is a global health challenge. Reactivation of HIV latency and killing of virus-infected cells, the... (Review)
Review
Eradication of latent human immunodeficiency virus (HIV) infection is a global health challenge. Reactivation of HIV latency and killing of virus-infected cells, the so-called "kick and kill" or "shock and kill" approaches, are a popular strategy for HIV cure. While antiretroviral therapy (ART) halts HIV replication by targeting multiple steps in the HIV life cycle, including viral entry, integration, replication, and production, it cannot get rid of the occult provirus incorporated into the host-cell genome. These latent proviruses are replication-competent and can rebound in cases of ART interruption or cessation. In general, a very small population of cells harbor provirus, serve as reservoirs in ART-controlled HIV subjects, and are capable of expressing little to no HIV RNA or proteins. Beyond the canonical resting memory CD4 T cells, HIV reservoirs also exist within tissue macrophages, myeloid cells, brain microglial cells, gut epithelial cells, and hematopoietic stem cells (HSCs). Despite a lack of active viral production, latently HIV-infected subjects continue to exhibit aberrant cellular signaling and metabolic dysfunction, leading to minor to major cellular and systemic complications or comorbidities. These include genomic DNA damage; telomere attrition; mitochondrial dysfunction; premature aging; and lymphocytic, cardiac, renal, hepatic, or pulmonary dysfunctions. Therefore, the arcane machineries involved in HIV latency and its reversal warrant further studies to identify the cryptic mechanisms of HIV reservoir formation and clearance. In this review, we discuss several molecules and signaling pathways, some of which have dual roles in maintaining or reversing HIV latency and reservoirs, and describe some evolving strategies and possible approaches to eliminate viral reservoirs and, ultimately, cure/eradicate HIV infection.
Topics: Animals; Apoptosis; Disease Reservoirs; HIV Infections; HIV-1; Humans; Models, Biological; Virus Latency
PubMed: 33672138
DOI: 10.3390/cells10020475 -
FEMS Microbiology Reviews Sep 2020Wild birds interconnect all parts of the globe through annual cycles of migration with little respect for country or continental borders. Although wild birds are... (Review)
Review
Wild birds interconnect all parts of the globe through annual cycles of migration with little respect for country or continental borders. Although wild birds are reservoir hosts for a high diversity of gamma- and deltacoronaviruses, we have little understanding of the ecology or evolution of any of these viruses. In this review, we use genome sequence and ecological data to disentangle the evolution of coronaviruses in wild birds. Specifically, we explore host range at the levels of viral genus and species, and reveal the multi-host nature of many viral species, albeit with biases to certain types of avian host. We conclude that it is currently challenging to infer viral ecology due to major sampling and technical limitations, and suggest that improved assay performance across the breadth of gamma- and deltacoronaviruses, assay standardization, as well as better sequencing approaches, will improve both the repeatability and interpretation of results. Finally, we discuss cross-species virus transmission across both the wild bird - poultry interface as well as from birds to mammals. Clarifying the ecology and diversity in the wild bird reservoir has important ramifications for our ability to respond to the likely future emergence of coronaviruses in socioeconomically important animal species or human populations.
Topics: Animals; Animals, Wild; Birds; Coronavirus; Coronavirus Infections; Disease Reservoirs; Gammacoronavirus; Host Specificity
PubMed: 32672814
DOI: 10.1093/femsre/fuaa026 -
Virologie (Montrouge, France) Aug 2019Current antiretroviral therapy allows the control of HIV replication but a relapse occurs most of the time in case of treatment interruption. The viral genome... (Review)
Review
Current antiretroviral therapy allows the control of HIV replication but a relapse occurs most of the time in case of treatment interruption. The viral genome integration explains this persistence of HIV in all body tissues, at very variable levels depending on their density of CD4 T-cells, HIV main target. Secondary lymphoid tissues are the most infected organs. Several techniques can be used to characterize the reservoir, detecting different forms of the virus. They are complementary to decipher the establishment of HIV reservoir during the primary infection and its dynamics afterwards. In peripheral blood, the earlier the initiation of treatment, the more important is the decrease in total HIV DNA. Early treatment prevents the progressive increase in stable integrated forms of HIV DNA and preserves immune cells from infection. A better understanding of HIV infection in controllers will also aid in the development of new therapeutic strategies targeting the reservoir.
Topics: Anti-HIV Agents; Biomarkers; Cells, Cultured; DNA, Viral; Dendritic Cells; Disease Progression; Disease Reservoirs; Drug Delivery Systems; HIV Infections; HIV-1; Humans; Lymphocytes; Lymphoid Tissue; Macrophages; Monocytes; Proviruses; Transcription, Genetic; Viral Tropism; Virus Integration; Virus Latency; Virus Replication
PubMed: 31414659
DOI: 10.1684/vir.2019.0784 -
PLoS Neglected Tropical Diseases Aug 2020Visceral leishmaniasis (VL) remains an important public health issue worldwide causing substantial morbidity and mortality. The Indian subcontinent accounted for up to... (Review)
Review
Visceral leishmaniasis (VL) remains an important public health issue worldwide causing substantial morbidity and mortality. The Indian subcontinent accounted for up to 90% of the global VL burden in the past but made significant progress during recent years and is now moving towards elimination. However, to achieve and sustain elimination of VL, knowledge gaps on infection reservoirs and transmission need to be addressed urgently. Xenodiagnosis is the most direct way for testing the infectiousness of hosts to the vectors and can be used to investigate the dynamics and epidemiology of Leishmania donovani transmission. There are, however, several logistic and ethical issues with xenodiagnosis that need to be addressed before its application on human subjects. In the current Review, we discuss the critical knowledge gaps in VL transmission and the role of xenodiagnosis in disease transmission dynamics along with its technical challenges. Establishment of state of the art xenodiagnosis facilities is essential for the generation of much needed evidence in the VL elimination initiative.
Topics: Animals; Asia; Asymptomatic Diseases; Disease Reservoirs; Humans; Leishmania donovani; Leishmaniasis, Visceral; Phlebotomus; Xenodiagnosis
PubMed: 32790716
DOI: 10.1371/journal.pntd.0008363 -
Medical Hypotheses Oct 2020Periodontal pockets are the major clinical manifestation of Periodontitis, a chronic inflammatory oral disease affecting the teeth-supporting tissues and has high...
Periodontal pockets are the major clinical manifestation of Periodontitis, a chronic inflammatory oral disease affecting the teeth-supporting tissues and has high prevalence in the adult population. Periodontal pockets are ideal environments for subgingival bacterial biofilms, that interact with the supragingival oral cavity, mucosal tissues of the pocket and a peripheral circulatory system. Periodontal pockets have been found to harbor viral species such as the Herpes simplex viruses' family. Recently, the SARS-CoV-2 has gained major interest of the scientific/medical community as it caused a global pandemic (Covid-19) and paralyzed the globe with high figures of infected people worldwide. This virus behavior is still partially understood, and by analyzing some of its features we hypothesized that periodontal pocket could be a favorable anatomical niche for the virus and thus acting as a reservoir for SARS-CoV-2.
Topics: Angiotensin-Converting Enzyme 2; Betacoronavirus; COVID-19; COVID-19 Testing; Clinical Laboratory Techniques; Coronavirus Infections; Disease Reservoirs; Host Microbial Interactions; Humans; Models, Biological; Mouth Mucosa; Pandemics; Peptidyl-Dipeptidase A; Periodontal Pocket; Pneumonia, Viral; Receptors, Virus; SARS-CoV-2
PubMed: 32504927
DOI: 10.1016/j.mehy.2020.109907