 Elephant endotheliotropic herpesviruses ( EEHV ) or Elephantid herpesvirus 1 ' is a type of herpesvirus , which can cause a highly fatal hemorrhagic disease when transmitted to young Asian elephants . In African elephants , related forms of these viruses , which have been identified in wild populations , are generally benign , occasionally surfacing to cause small growths or lesions . However , some types of EEHV can cause a highly fatal disease in Asian elephants , which kills up to 80 % of severely affected individuals . The disease can be treated with the rapid application of antiviral drugs , but this has only been effective in around a third of cases . 
