**1.2 A sporadic encephalitis in a giraffe**

128 Non-Flavivirus Encephalitis

occurrence was sudden death of one gazelle, and then others showed neurological symptoms in turn over 2-week period (Fig. 1). The neurological symptoms in the gazelles were depression, incoordination, nystagmus, and convulsion. Laboratory tests showed occult blood and albumin in the urine samples. Seven out of the nine gazelles died. No evidence of infection was found in this foal. The other two gazelles recovered. The remaining one was a newborn that died of malnutrition, because the sick mother gazelle refused nursing. One of the recovered gazelles delivered a healthy neonate two months later. All dead gazelles did not have apparent changes at necropsy. Microscopically, all dead gazelles except the foal of malnutrition had nonsuppurative encephalitis, which characterized by neuronal degeneration and intracellular inclusion bodies (Fukushi et al.,

Fig. 1. Outbreak of lethal enzootic encephalitis in Thomson's gazelles

Homogenates of the brain, spinal cord, kidney, liver, lung and spleen were inoculated into Madin-Darby bovine kidney (MDBK) cells. Cells inoculated with the brain homogenate showed cytopathic effect characterized as syncitium formation accompanying nuclear inclusion bodies and detachment (Fig. 2), indicating the isolation of a virus. Physicochemical characterization of the isolate showed that the isolate was chloroform sensitive DNA virus of about 150 to 200 nm diameter. Considering the characteristics, the isolate was identified as a herpesvirus. Serum neutralization tests using antisera against pseudorabies virus, bovine herpesvirus 1, malignant catarrahl fever virus, and equine herpesvirus 1 (EHV-1) indicated that the isolated virus should be EHV-1 or EHV-1 related virus. Comparing DNA fingerprints and nucleotide sequences of a glycoprotein B gene and a glycoprotein G gene, the isolate should be regarded as a new herpesvirus, gazelles herpesvirus 1 (GHV-1) at first (Fukushi et al., 1996). DNA fingerprints of GHV-1 were different from those of EHV- 1, EHV-4, and EHV-8, although GHV-1 cross-reacted with EHV-1 and EHV-4 in neutralization tests. Southern analysis indicated that GHV-1 shared sequence homology with EHV-1.

1996, Yanai et al., 1998).

An 18-month-old male reticulated giraffe (*Giraffa camelopardalis reticulate*) housed in a zoo presented with a one and a half day history of incoordination, stumbling, and abdominal pain and died (Hoenerhoff et al., 2006). Nonsuppurative encephalitis was histopathologically found in the brain of giraffe. Several zebras (*Equus burchelli*), which were apparently healthy, were housed in a pen with the giraffe. Herpesvirus was isolated from the reticulated giraffe. The isolated virus was identified as EHV-1 by PCR and monoclonal antibody assay at first. The giraffe had been housed with a group of zebras that were serologically positive for EHV-1. Considering the situation and histopathological findings, there was a possibility that the isolate could be EHV-9. Several gene sequences of the giraffe virus were almost identical to those of EHV-9 (Samy et al., 2008). Therefore the giraffe virus was EHV-9.
