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Bats as Reservoir Hosts: Exploring Novel Viruses in New World Bats
Başlık:
Bats as Reservoir Hosts: Exploring Novel Viruses in New World Bats
Yazar:
Malmlov, Ashley, author.
ISBN:
9780438042100
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (149 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Tony Schountz Committee members: Richard Bowen; Page Dinsmore; Kristy Pabilonia.
Özet:
Order Chiroptera is oft incriminated for their capacity to serve as reservoirs for many high profile human pathogens, including Ebola virus, Marburg virus, severe acute respiratory syndrome coronavirus, Nipah virus and Hendra virus. Additionally, bats are postulated to be the original hosts for such virus families and subfamilies as Paramyxoviridae and Coronavirinae. Given the perceived risk bats may impart upon public health, numerous explorations have been done to delineate if in fact bats do host more viruses than other animal species, such as rodents, and to ascertain what is unique about bats to allow them to maintain commensal relationships with zoonotic pathogens and allow for spillover. Of particular interest is data that demonstrate type I interferons (IFN), a first line defense to invading viruses, may be constitutively expressed in bats. The constant expression of type I IFNs would hamper viral infection as soon as viral invasion occurred, thereby limiting viral spread and disease. Another immunophysiological trait that may facilitate the ability to harbor viruses is a lack of somatic hypermutation and affinity maturation, which would decrease antibody affinity and neutralizing antibody titers, possibly facilitating viral persistence.
In 2009 and 2010 two novel influenza A viruses (IAV) were discovered via qRT-PCR using pan-influenza primers in New World bat species. Given the unique hemagglutinin (HA) and neuraminidase (NA) glycoproteins compared to those already recognized, the two viruses were classified as H17N10 and H18N11. H17N10 IAV genome was discovered in rectal swabs collected from little yellow-shouldered bats in Guatemala, and H18N11 IAV genome was discovered in a rectal swab and gastrointestinal tract of a flat-faced fruit bat from Peru. The entire sequences for both viruses were identified using next generation and Sanger sequencing, but the virus was never isolated from wild bat populations. Both viruses differ from canonical IAVs in that the HA does not bind to the host sialic acid receptor and the function of NA remains undetermined. Given the divergence from other IAVs, the attention bats receive as reservoir hosts, and the lack of isolation of wild virus, H17N10 and H18N11 remain shrouded in mystery. Reverse genetics was used to rescue both viruses and we performed experimental infections in Jamaican fruit bats (Artibeus jamaicensis), drawing upon the colony housed at Colorado State University. Evidence for H17N10 infection could not be elicited after inoculation, and thus it was concluded that Jamaican fruit bats may not be susceptible. Bats inoculated with H18N11 seroconverted (determined by ELISA), had viral RNA detected in rectal but not oral swabs by qRT-PCR, and had viral RNA present in the length of the gastrointestinal tract detected by qRT-PCR. Hematoxylin and eosin stain used to characterize histopathology revealed minimal pathology that was predominately localized to the gastrointestinal tract in the form of neutrophilic, plasmacytic and lymphocytic cellular infiltration. Furthermore, two naive transmission bats were exposed to inoculated bats and demonstrated seroconversion and viral RNA detected in rectal swabs by qRT-PCR. Results demonstrate that Jamaican fruit bats are susceptible to H18N11 and indicate transmission occurs fecal-orally. Tissue tropism is for the gastrointestinal tract. These data recapitulate transmission and tissue tropism as seen in the reservoir of IAV, water fowl, and low-pathogenic avian influence viruses in gallinaceous birds. However, this does not indicate that bats may be a reservoir for influenza viruses as H18N11 is not known to cause disease in humans and is highly divergent from other IAVs. More likely, this demonstrates an early divergence of H18N11 from other IAVs and a long-lived co-evolution between the host and the virus. Further investigation of H18N11 may provide information on relationships between bats and their viromes, which is of great importance given so many bat species harbor highly pathogenic zoonotic viruses.
The impact of Zika virus (ZIKV) on the New World has been great---infecting more than 200,000 people and manifesting in some patients as severe neurological complications including microcephaly in infected fetuses and Guillain-Barre syndrome. An enzootic cycle is implicated as an important part of viral ecology, yet little is known about this cycle. Historically, different bat species demonstrated experimental susceptibility to ZIKV as they seroconvert, have neurological disease, viremia and ZIKV positive tissues. Jamaican fruit bats are endemic to a region that temporally overlaps with the distribution of ZIKV in the Americas and Caribbean. We sought to identify if these bats were susceptible to ZIKV and conducted a time course study to delineate progression of viral infection and pathophysiology. ELISAs were used to identify seroconversion. Quantitative RT-PCR and immunohistochemistry were used to determine tissue tropism, and hematoxylin and eosin stain was used to characterize histopathology. (Abstract shortened by ProQuest.).
Notlar:
School code: 0053
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(678222.1) | 678222-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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