Equine herpesvirus 9 (EHV-9), also known as gazelle herpesvirus 1 (GHV-1), has been identified as the etiologic agent involved in an outbreak of fulminant neurologic disease in Thomson’s gazelles (Gazella thomsoni) as well as encephalitic disease in a polar bear (Ursus maritimus) and a reticulated giraffe (Giraffa camelopardalis reticulate).1-4 Additionally, the virus has been implicated as the cause of respiratory disease in Grevy’s zebras (Equus grevysi) and abortion in a Persian onager (Equus hemionus onager),3 and has caused clinical signs in a variety of experimentally infected domesticated and exotic species. Zebras are thought to be the natural hosts of EHV-9, thus provoking concern regarding potential interspecies transmission when zebras are kept in zoo exhibits with Thomson’s gazelles. With cross-reactivity between equine herpesvirus 1 (EHV-1), equine herpesvirus 4 (EHV-4) and EHV-9, diagnostic screening is possible with available ELISA methodology. Banked serum samples from fourteen Thomson’s gazelles, six Common zebras, and four Hartmann’s mountain zebras were submitted for EHV-1 antibody titers. None of the sampled animals had previously been vaccinated against EHV-1 or EHV-4. All zebras had positive EHV-1 titers while all Thomson’s gazelles had negative titers. Further analysis using viral isolation or PCR would be necessary to determine if virus is present in animals with positive titers.
1. Fukushi, H., T. Tomita, A. Taniguchi, Y. Ochiai, R. Kirisawa, T. Matsumura, T. Yanai, T. Masegi, T. Yamaguchi, and K. Hirai. 1997. Gazelle herpesvirus 1: a new neurotropic herpesvirus immunologically related to equine herpesvirus 1. Virology 226: 34–44.
2. Kasem, S., S. Yamada, M. Kiupel, M. Woodruff, K. Ohya, and H. Fukushi. 2008. Equine herpesvirus type 9 in giraffe with encephalitis. Emerg. Infect. Dis. 14: 1948–1949.
3. Schrenzel, M.D., T.A. Tucker, T.A. Donovan, M.D.M. Busch, A.G. Wise, R.K. Maes, and M. Kiupel. 2008. New hosts for equine herpesvirus 9. Emerg. Infect. Dis. 14: 1616–1619.
4. Yanai, T., T. Sakai, H. Fukushi, K. Hirai, M. Narita, H. Sakai, and T. Masegi. 1996. Neuropathological study of gazelle herpesvirus 1 (equine herpesvirus 9) infection in Thomson’s gazelles (Gazella thomsoni). J. Comp. Path. 119: 159–168.