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Viruses Oct 2021Although there have been documented Ebola virus disease outbreaks for more than 40 years, the natural reservoir host has not been identified. Recent studies provide...
Although there have been documented Ebola virus disease outbreaks for more than 40 years, the natural reservoir host has not been identified. Recent studies provide evidence that the Angolan free-tailed bat (), an insectivorous microbat, is a possible ebolavirus reservoir. To investigate the potential role of this bat species in the ecology of ebolaviruses, replication, tolerance, and persistence of Ebola virus (EBOV) were investigated in 10 different primary bat cell isolates from . Varying EBOV replication kinetics corresponded to the expression levels of the integral membrane protein NPC1. All primary cells were highly tolerant to EBOV infection without cytopathic effects. The observed persistent EBOV infection for 150 days in lung primary cells, without resultant selective pressure leading to virus mutation, indicate the intrinsic ability of EBOV to persist in this bat species. These results provide further evidence for this bat species to be a likely reservoir of ebolaviruses.
Topics: Animals; Chiroptera; Disease Outbreaks; Disease Reservoirs; Ebolavirus; Hemorrhagic Fever, Ebola; Immune Tolerance; Virus Replication
PubMed: 34834992
DOI: 10.3390/v13112186 -
Revue Scientifique Et Technique... Dec 2006This article reviews the conditions that allow an infectious or parasitic pathogen to migrate from a wild reservoir to domestic animals and/or humans, and examines the... (Review)
Review
This article reviews the conditions that allow an infectious or parasitic pathogen to migrate from a wild reservoir to domestic animals and/or humans, and examines the possibility of a new disease emerging as a result. The review presents epidemiological mechanisms grouped into three principal models, illustrating them with examples: the intentional or accidental release of the reservoir host or pathogen; the exceeding of a numerical, ecological or behavioural threshold in the host populations and/or increased exposure of humans and domestic animals due to changes in behaviour; and lastly, an "adaptive" leap that ensures that a new host species finally succumbs to the pathogen and that it spreads among the conquered population. The authors examine the lessons to be drawn from such occurrences in terms of surveillance, prophylaxis and prevention.
Topics: Animal Diseases; Animal Husbandry; Animals; Animals, Domestic; Animals, Wild; Communicable Disease Control; Communicable Diseases, Emerging; Disease Reservoirs
PubMed: 17361759
DOI: No ID Found -
PLoS Neglected Tropical Diseases 2009
Topics: Animals; Databases, Factual; Disease Reservoirs; Disease Vectors; Humans; Internet
PubMed: 19333367
DOI: 10.1371/journal.pntd.0000378 -
Philosophical Transactions of the Royal... Sep 2019Pathogen circulation among reservoir hosts is a precondition for zoonotic spillover. Unlike the acute, high morbidity infections typical in spillover hosts, infected...
Pathogen circulation among reservoir hosts is a precondition for zoonotic spillover. Unlike the acute, high morbidity infections typical in spillover hosts, infected reservoir hosts often exhibit low morbidity and mortality. Although it has been proposed that reservoir host infections may be persistent with recurrent episodes of shedding, direct evidence is often lacking. We construct a generalized SEIR (susceptible, exposed, infectious, recovered) framework encompassing 46 sub-models representing the full range of possible transitions among those four states of infection and immunity. We then use likelihood-based methods to fit these models to nine years of longitudinal data on henipavirus serology from a captive colony of Eidolon helvum bats in Ghana. We find that reinfection is necessary to explain observed dynamics; that acute infectious periods may be very short (hours to days); that immunity, if present, lasts about 1-2 years; and that recurring latent infection is likely. Although quantitative inference is sensitive to assumptions about serology, qualitative predictions are robust. Our novel approach helps clarify mechanisms of viral persistence and circulation in wild bats, including estimated ranges for key parameters such as the basic reproduction number and the duration of the infectious period. Our results inform how future field-based and experimental work could differentiate the processes of viral recurrence and reinfection in reservoir hosts. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'.
Topics: Animals; Animals, Zoo; Chiroptera; Disease Reservoirs; Ghana; Henipavirus; Henipavirus Infections; Prevalence; Seroepidemiologic Studies
PubMed: 31401962
DOI: 10.1098/rstb.2019.0021 -
Journal of Comparative Pathology Jan 2011Eurasian badgers (Meles meles) are an important wildlife reservoir of tuberculosis (Mycobacterium bovis) infection in Ireland and the United Kingdom. As part of national... (Review)
Review
Eurasian badgers (Meles meles) are an important wildlife reservoir of tuberculosis (Mycobacterium bovis) infection in Ireland and the United Kingdom. As part of national programmes to control tuberculosis in livestock, considerable effort has been devoted to studying the disease in badgers and this has lead to a rapid increase in our knowledge of tuberculosis in this host. Tuberculosis in badgers is a chronic infection and in a naturally-infected population the severity of disease can vary widely, from latent infection (infection without clinical signs and no visible lesions) to severe disease with generalized pathology. The high prevalence of pulmonary infection strongly supports the lungs as the principal site of primary infection and that inhalation of infectious aerosol particles is the principal mode of transmission. However, other routes, including transmission via infected bite wounds, are known to occur. The ante-mortem diagnosis of infection is difficult to achieve, as clinical examination and immunological and bacteriological examination of clinical samples are insensitive diagnostic procedures. Because infection in the majority of badgers is latent, the gross post-mortem diagnosis is also insensitive. A definitive diagnosis can only be made by the isolation of M. bovis. However, to gain a high level of sensitivity in the bacteriological examination, a large number of tissues from each badger must be cultured and sensitive culture methods employed. The transmission and maintenance of M. bovis in badger populations are complex processes where many factors influence within-population prevalence and rates of transmission. Badger social structures and the longevity of infected animals make them an ideal maintenance host for M. bovis infection. Badgers are directly implicated in the transmission of infection to cattle and the inability to eradicate the disease from cattle is, in part, a consequence of the interactions between the two species. A detailed understanding and knowledge of the epidemiology and pathogenesis of the disease are recognized as fundamental for devising new strategies to control infection with a view to limiting interspecies transmission. Vaccination, in spite of formidable challenges, is seen as the best long-term strategy option and studies with captive badgers have shown that vaccination with M. bovis bacillus Calmette-Guérin (BCG) induces protection when delivered by a variety of routes. Continued research is required to develop effective technologies to control the disease both in badgers and cattle. A combination of strategies, which employ the optimal use and targeting of resources, is likely to make a significant contribution towards eradication of the disease.
Topics: Animals; BCG Vaccine; Disease Reservoirs; Mustelidae; Mycobacterium bovis; Tuberculosis
PubMed: 21131004
DOI: 10.1016/j.jcpa.2010.10.003 -
Veterinary Microbiology Mar 2006Gammaherpesviruses are members of an emerging subfamily among the Herpesviridae. Two genera are discriminated: (i) lymphocryptovirus, including its type species... (Review)
Review
Gammaherpesviruses are members of an emerging subfamily among the Herpesviridae. Two genera are discriminated: (i) lymphocryptovirus, including its type species Epstein-Barr virus (EBV), and (ii) rhadinovirus, including viruses of interest for medicine, veterinary medicine, and biomedical research, i.e. alcelaphine herpesvirus 1, bovine herpesvirus 4, equine herpesvirus 2, human herpesvirus 8, mouse herpesvirus 68, and ovine herpesvirus 2 (OvHV-2). The perception that these viruses have a narrow host range is misleading, since they cover a surprisingly wide host range, both on the cellular and the organism's level. For example, the natural range of OvHV-2 infection extends over a common animal order. While the host range determinants of EBV are well known, the corresponding features of the rhadinoviruses need still to be defined. Similarly, the gene expression patterns of the veterinary rhadinoviruses during latency require further characterization. In vivo, the gammaherpesviruses have evolved to actively protect their latently infected cells from being destroyed by immune functions of their native host. In return, those reservoir hosts have evolved to being infected and transmit the virus without overt disease symptoms. However, a balanced immune response needs to be in control over the number of infected cells. Virus excretion is usually at low level and may occur either constantly or intermittently. Animal species that are targeted by the virus but did not participate in the process of co-evolution as well as hosts with immune deficiencies are known to loose control over the amount of latently infected cells, which results in the development of lethal diseases, such as malignant catarrhal fever or Kaposi's sarcoma.
Topics: Animals; Disease Reservoirs; Gammaherpesvirinae; Gene Expression Regulation, Viral; Herpesviridae Infections; Species Specificity; Virus Latency
PubMed: 16332416
DOI: 10.1016/j.vetmic.2005.11.008 -
Journal of Medical Primatology Feb 2020Although the domestic dog is the most important reservoir of visceral leishmaniasis in urban areas, there have been an increasing number of reports of naturally... (Review)
Review
Although the domestic dog is the most important reservoir of visceral leishmaniasis in urban areas, there have been an increasing number of reports of naturally occurring leishmaniasis in non-human primates. Reported cases affecting neotropical and Old World non-human primates as well as their potential role as reservoirs were reviewed.
Topics: Animals; Disease Reservoirs; Leishmaniasis, Visceral; Monkey Diseases; Primates
PubMed: 31595524
DOI: 10.1111/jmp.12441 -
Revue Scientifique Et Technique... Aug 2006Escherichia coli is one of the main inhabitants of the intestinal tract of most mammalian species, including humans, and birds. Shiga toxin-producing E. coli (STEC),... (Review)
Review
Escherichia coli is one of the main inhabitants of the intestinal tract of most mammalian species, including humans, and birds. Shiga toxin-producing E. coli (STEC), also called verotoxinogenic E. coli, usually do not cause disease in animals but may cause watery diarrhoea, haemorrhagic colitis, and/or haemolytic uraemic syndrome in humans. Zoonotic STEC include the O157:H7 strains and, with increasing frequency, certain non-O157 strains. The importance of non-O157 zoonotic strains is probably underestimated as they have been less well characterised and are more difficult to detect in samples than O157:H7. Another large subset of STEC strains has been isolated from animals but has not, at the present time, been associated with disease in animals or humans. Cattle and other ruminants are the most important reservoir of zoonotic STEC, which are transmitted to humans through the ingestion of foods or water contaminated with animal faeces, or through direct contact with the infected animals or their environment. The main sources of STEC infection of cattle on-farm are the drinking water, the feed, and the immediate environment of the animal. Risk factors that have been identified for infection of animals with O157 STEC include age, weaning, movement of the animals, season, feed composition, and the ability of the bacteria to persist in the environment. On-farm control of the zoonotic risk of human infection with STEC should primarily target the main source of contamination: the animal reservoir. Various strategies to reduce intestinal colonisation of cattle by zoonotic STEC have been tried with varying results, including vaccination, treatment with probiotics, such as direct-fed microbials or competitive exclusion, administration of bacteriophages, and modification of the diet.
Topics: Animal Husbandry; Animals; Cattle; Disease Reservoirs; Escherichia coli; Escherichia coli Infections; Escherichia coli O157; Food Contamination; Food Microbiology; Humans; Meat; Zoonoses
PubMed: 17094697
DOI: No ID Found -
The Veterinary Record Oct 2019
Topics: Animals; Cattle; Disease Reservoirs; England; Tuberculosis, Bovine
PubMed: 31653722
DOI: 10.1136/vr.l6176 -
Wiener Klinische Wochenschrift Oct 2010Ebola and Marburg virus, forming the Filoviridae family, cause hemorrhagic fever in countries of sub-Saharan Africa. These viral diseases are characterized by a sudden... (Review)
Review
Ebola and Marburg virus, forming the Filoviridae family, cause hemorrhagic fever in countries of sub-Saharan Africa. These viral diseases are characterized by a sudden epidemic occurrence as well as a high lethality. Even though a reservoir host has not been approved yet, literature indicates the order of bats (Chiroptera) as a potential reservoir host. Significant references lead to a delineation of a hypothetical ecosystem of Filoviridae including Chiroptera. IgG-specific Ebola-Zaire antibodies were detected in Hammer-headed Bats (Hypsignathus monstrosus), Epauletted Fruit Bats (Epomops franqueti), and Little Collared Fruit Bats (Myonycteris torquata) during Ebola outbreaks between 2001 and 2005 in Gabon and the Republic of the Congo. The discovery of IgG-specific-Marburg virus antibodies and virus-specific ribonucleic acid in Egyptian Fruit Bats (Rousettus aegyptiacus) provided further indication for the exploration of the reservoir host. In 2007, the Marburg virus isolation could for the first time be accomplished directly from apparently healthy and naturally infected Egyptian Fruit Bats (Rousettus aegyptiacus) in Kitaka Mine (Uganda). Risk groups can be defined through chronological reprocessing and interpretation of existing epidemic-outbreaks on the African continent and the search for infection reasons of the index cases. The following risk factors for an infection with Ebola or Marburg virus must be put into consideration: Contact with and consumption of wild animal carcasses, sightseeing in caves as well as work in mines. The focus of this review is the demonstration of risk profiles and their exposure to Chiroptera and other potential reservoir hosts.
Topics: Africa; Animals; Chiroptera; Disease Outbreaks; Disease Reservoirs; Incidence; Virus Diseases
PubMed: 20924703
DOI: 10.1007/s00508-010-1434-x