Equine herpesvirus type 1 and 9 (EHV-1 and EHV-9) prevalence and biology in zoo and wild animals
Although EHV-1 infections are mainly restricted to equine species, there is increasing evidence that EHV-1 can cross species barriers and spread beyond its natural equid hosts. EHV-9 is the recently discovered virus strain of equine herpesviruses with an unknown natural host. Both EHV-1 and EHV-9 in...
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| Other Authors: | , , , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
| Published: |
2016
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| Online Access: | https://refubium.fu-berlin.de/handle/fub188/9922 https://doi.org/10.17169/refubium-14120 https://nbn-resolving.org/urn:nbn:de:kobv:188-fudissthesis000000103300-1 |
| Summary: | Although EHV-1 infections are mainly restricted to equine species, there is increasing evidence that EHV-1 can cross species barriers and spread beyond its natural equid hosts. EHV-9 is the recently discovered virus strain of equine herpesviruses with an unknown natural host. Both EHV-1 and EHV-9 infections of non-definitive hosts often result in neuronal infection with high case fatality rates. However, the questions remain: what the natural host(s) and the complete host range of both viruses are? It becomes urgent to answer these questions after a series of fatal infections which have been detected in the last few years. Detection of a new recombinant EHV-1/EHV-9 virus strain with fatalities in polar bear and Indian rhinoceros requires further investigation regarding the origin of the recombinant virus. Cumulative data suggested that the recombinant viruses originated in zebras. However, it is still unclear whether recombination occurred in captive zebras or in wild zebras. Similarly, it is unclear whether recombination is a rare or frequent event in zebras. The seroprevalence survey conducted in this thesis demonstrated that EHV-1 and EHV-9 have evolved a broad host range among African mammals including distantly related perissodactyls. Although the high prevalence of EHV-9 in African rhinoceros suggested that this species could be a reservoir or secondary host to the virus, molecular studies showed the ability of both EHV-1 and EHV-9 to induce infection in zebra with the ability of EHV-9 to establish latency. The co-occurrence of EHV-1 and EHV-9 in the same zebra supports the hypothesis that zebras are a natural host for both viruses where recombination can take place. However, one cannot exclude the role of African rhinoceros in virus transmission. Further molecular studies to investigate different viral strains circulating in African rhinoceros populations and whether they differ from zebra isolates are required. Deaths among animals infected with recombinant EHV-1 strains were reported in Indian ... |
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