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Kuno G, Mackenzie JS, Junglen S, Hubálek Z, Plyusnin A, Gubler DJ. Vertebrate Reservoirs of Arboviruses: Myth, Synonym of Amplifier, or Reality? Viruses 2017; 9:E185. [PMID: 28703771 PMCID: PMC5537677 DOI: 10.3390/v9070185] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/10/2017] [Accepted: 07/10/2017] [Indexed: 02/07/2023] Open
Abstract
The rapid succession of the pandemic of arbovirus diseases, such as dengue, West Nile fever, chikungunya, and Zika fever, has intensified research on these and other arbovirus diseases worldwide. Investigating the unique mode of vector-borne transmission requires a clear understanding of the roles of vertebrates. One major obstacle to this understanding is the ambiguity of the arbovirus definition originally established by the World Health Organization. The paucity of pertinent information on arbovirus transmission at the time contributed to the notion that vertebrates played the role of reservoir in the arbovirus transmission cycle. Because this notion is a salient feature of the arbovirus definition, it is important to reexamine its validity. This review addresses controversial issues concerning vertebrate reservoirs and their role in arbovirus persistence in nature, examines the genesis of the problem from a historical perspective, discusses various unresolved issues from multiple points of view, assesses the present status of the notion in light of current knowledge, and provides options for a solution to resolve the issue.
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Affiliation(s)
- Goro Kuno
- Formerly at the Division of Vector-Borne Infectious Diseases, Centers for Control and Prevention, Fort Collins, CO, USA.
| | - John S Mackenzie
- Faculty of Medical Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
- Division of Microbiology & Infectious Diseases, PathWest, Nedlands, Western Australia 6009.
| | - Sandra Junglen
- Institute of Virology, Charité-Universitätsmedizin Berlin, Helmut-Ruska-Haus, Chariteplatz 1, 10117 Berlin, Germany.
| | - Zdeněk Hubálek
- Institute of Vertebrate Biology, Academy of Sciences of Czech Republic, 60365 Brno, Czech Republic.
| | - Alexander Plyusnin
- Department of Virology, University of Helsinki, Haartmaninkatu 3, University of Helsinki, 00014 Helsinki, Finland.
| | - Duane J Gubler
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, 8 College Rd., Singapore 169857 Singapore.
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Elevated testosterone advances onset of migratory restlessness in a nearctic-neotropical landbird. Behav Ecol Sociobiol 2014. [DOI: 10.1007/s00265-013-1671-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Jankowski MD, Williams CJ, Fair JM, Owen JC. Birds shed RNA-viruses according to the pareto principle. PLoS One 2013; 8:e72611. [PMID: 23991129 PMCID: PMC3749140 DOI: 10.1371/journal.pone.0072611] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Accepted: 07/12/2013] [Indexed: 01/12/2023] Open
Abstract
A major challenge in disease ecology is to understand the role of individual variation of infection load on disease transmission dynamics and how this influences the evolution of resistance or tolerance mechanisms. Such information will improve our capacity to understand, predict, and mitigate pathogen-associated disease in all organisms. In many host-pathogen systems, particularly macroparasites and sexually transmitted diseases, it has been found that approximately 20% of the population is responsible for approximately 80% of the transmission events. Although host contact rates can account for some of this pattern, pathogen transmission dynamics also depend upon host infectiousness, an area that has received relatively little attention. Therefore, we conducted a meta-analysis of pathogen shedding rates of 24 host (avian) - pathogen (RNA-virus) studies, including 17 bird species and five important zoonotic viruses. We determined that viral count data followed the Weibull distribution, the mean Gini coefficient (an index of inequality) was 0.687 (0.036 SEM), and that 22.0% (0.90 SEM) of the birds shed 80% of the virus across all studies, suggesting an adherence of viral shedding counts to the Pareto Principle. The relative position of a bird in a distribution of viral counts was affected by factors extrinsic to the host, such as exposure to corticosterone and to a lesser extent reduced food availability, but not to intrinsic host factors including age, sex, and migratory status. These data provide a quantitative view of heterogeneous virus shedding in birds that may be used to better parameterize epidemiological models and understand transmission dynamics.
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Affiliation(s)
- Mark D. Jankowski
- United States Fish and Wildlife Service, Pocatello, Idaho, United States of America
- Department of Zoology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | | | - Jeanne M. Fair
- Biosecurity and Public Health, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America
| | - Jennifer C. Owen
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, Michigan, United States of America
- Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan, United States of America
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Nemeth NM, Oesterle PT. West Nile virus from an avian conservation perspective. ACTA ACUST UNITED AC 2013. [DOI: 10.1111/izy.12031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- N. M. Nemeth
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine; University of Georgia; Athens Georgia 30602 USA
- Department of Pathobiology; Ontario Veterinary College; University of Guelph; Guelph Ontario N1G 2W1 Canada
| | - P. T. Oesterle
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine; University of Georgia; Athens Georgia 30602 USA
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Wheeler SS, Langevin SA, Brault AC, Woods L, Carroll BD, Reisen WK. Detection of persistent west nile virus RNA in experimentally and naturally infected avian hosts. Am J Trop Med Hyg 2012; 87:559-64. [PMID: 22826479 DOI: 10.4269/ajtmh.2012.11-0654] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
To determine whether West Nile virus (WNV) persistent infection in avian hosts may potentially serve as an overwintering mechanism, House Sparrows and House Finches, experimentally and naturally infected with several strains of WNV, and two naturally infected Western Scrub-Jays were held in mosquito-proof outdoor aviaries from 2007-March 2008. Overall, 94% (n = 36) of House Sparrows, 100% (n = 14) of House Finches and 2 Western Scrub-Jays remained WNV antibody positive. When combined by species, 37% of the House Sparrows, 50% of the House Finches, and 2 Western Scrub-Jays were WNV RNA positive at necropsy, up to 36 weeks post-infection. Infectious WNV was not detected. Our study supports the hypothesis that some avian hosts support the long-term persistence of WNV RNA, but it remains unresolved whether these infections relapse to restart an avian-arthropod transmission cycle and thereby serve as an overwintering mechanism for WNV.
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Affiliation(s)
- Sarah S Wheeler
- Center for Vectorborne Diseases, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
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Owen JC, Nakamura A, Coon CA, Martin LB. The effect of exogenous corticosterone on West Nile virus infection in Northern Cardinals (Cardinalis cardinalis). Vet Res 2012; 43:34. [PMID: 22520572 PMCID: PMC3372427 DOI: 10.1186/1297-9716-43-34] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 04/21/2012] [Indexed: 12/25/2022] Open
Abstract
The relationship between stress and disease is thought to be unambiguous: chronic stress induces immunosuppression, which likely increases the risk of infection. However, this link has not been firmly established in wild animals, particularly whether stress hormones affect host responses to zoonotic pathogens, which can be transmitted to domesticated animal, wildlife and human populations. Due to the dynamic effects of stress hormones on immune functions, stress hormones may make hosts better or poorer amplifying hosts for a pathogen contingent on context and the host species evaluated. Using an important zoonotic pathogen, West Nile virus (WNV) and a competent host, the Northern Cardinal (Cardinalis cardinalis), we tested the effects of exogenous corticosterone on response to WNV infection. Corticosterone was administered at levels that individuals enduring chronic stressors (i.e., long-term inclement weather, food shortage, anthropogenic pollution) might experience in the wild. Corticosterone greatly impacted mortality: half of the corticosterone-implanted cardinals died between five - 11 days post-inoculation whereas only one of nine empty-implanted (control) birds died. No differences were found in viral titer between corticosterone- and empty-implanted birds. However, cardinals that survived infections had significantly higher average body temperatures during peak infection than individuals that died. In sum, this study indicates that elevated corticosterone could affect the survival of WNV-infected wild birds, suggesting that populations may be disproportionately at-risk to disease in stressful environments.
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Affiliation(s)
- Jennifer C Owen
- 13 Natural Resources, Michigan State University, Department of Fisheries and Wildlife, East Lansing, MI, USA.
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Brown CR, O'Brien VA. Are Wild Birds Important in the Transport of Arthropod-borne Viruses? ACTA ACUST UNITED AC 2011. [DOI: 10.1525/om.2011.71.1.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Owen JC, Moore FR, Williams AJ, Stark L, Miller EA, Morley VJ, Krohn AR, Garvin MC. Test of recrudescence hypothesis for overwintering of eastern equine encephalomyelitis virus in gray catbirds. JOURNAL OF MEDICAL ENTOMOLOGY 2011; 48:896-903. [PMID: 21845951 DOI: 10.1603/me10274] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Eastern equine encephalitis virus (EEEV; family Togaviridae, genus Alphavirus) epizootics are infrequent, but they can lead to high mortality in infected horses and humans. Despite the importance of EEEV to human and animal health, little is known about how the virus overwinters and reinitiates transmission each spring, particularly in temperate regions where infected adult mosquitoes are unlikely to survive through the winter. One hypothesis to explain the mechanism by which this virus persists from year to year is the spring recrudescence of latent virus in avian reservoir hosts. In this study, we tested the recrudescence hypothesis with gray catbirds (Dumatella carolinensis) captured in northern Ohio (July-August 2007). Birds were experimentally infected with EEEV on 1 October 2007. In January 2008, they were then exposed to exogenous testosterone and/or extended photoperiod to initiate reactivation of latent EEEV infection. All birds became viremic with EEEV, with mean viremia of 6.0 log10 plaque-forming units/ml serum occurring at 1 d postinoculation. One male in the testosterone, long-day treatment group had EEEV viral RNA in a cloacal swab collected on 18 January 2008. Otherwise, no other catbirds exhibited reactivated infections in cloacal swabs or blood. Antibody titers fluctuated over the course of the study, with lowest titers observed in January 2008, which corresponded with the lowest mean weight of the birds. No EEEV viral RNA was detected in the blood, kidney, spleen, brain, liver, and lower intestine upon necropsy at 19 wk postinfection.
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Affiliation(s)
- Jennifer C Owen
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 44824, USA.
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