Elephant endotheliotropic herpesvirus (EEHV) is one of the most devastating infections and causes of mortality in captive Asian elephant populations. The virus leads to a severe, painful and distressing disease syndrome in juvenile elephants called haemorrhagic disease (EEHV-HD), and chances of survival are incredibly low. Free-living cases of EEHV-HD in juvenile Asian elephants have been reported in India after post-mortem examinations, suggesting that the disease is also occurring in the wild.
This project aimed to find a non-invasive method of detection of EEHV through Polymerase Chain Reaction (PCR) of faecal samples, which could be applied to both captive and free-living elephants to improve the understanding of the virus, its disease state, and aid in disease management.
This study was undertaken in Thailand; paired samples of saliva and faeces were collected from six captive juvenile Asian elephants over a 12-week period. Of the 28 samples suitable for EEHV testing, two faecal samples were found to be positive for EEHV4 and confirmed using gel electrophoresis. Two further samples were found to be positive, one for EEHV1 and one for EEHV4, however they were not verified using gel electrophoresis due to time constraints.
This study presents the first evidence of a non-invasive method of detection of EEHV4 excretion in captive Asian elephants, through PCR of faeces. Evidence gathered during this study shows the likelihood of a practically applicable method being developed in the future, which could better our understanding of EEHV epidemiology in free-living herds. Much further research is required to optimise methods of sample collection, sample storage and laboratory techniques since many limitations were encountered with DNA extraction and amplification during the study period, and the final sample size was small as a result of this.