 The virus has been identified in the pulmonary nodules of African elephants as far back as the 1970s . The first recognised fatal case of EEHV in an Asian elephant was identified at the National Zoo in Washington , D.C. , in 1995 ; testing on stored tissue samples was able to identify a number of earlier deaths as being due to the same virus . These cases have so far been identified as early as 1983 . Since this date , there have been a total of 54 more cases in North America and Europe , nine of which were successfully treated . The May 2009 deaths of two calves at Whipsnade Zoo were not included in this calculation . This gives a fatality rate of over 80 % among known symptomatic disease cases . In cases where antiviral medication was applied , treatment was effective in about one in three cases . As of 2005 , there were twelve cases where famciclovir had been used , eight of which were fatal . As a fraction of the overall population , it has been calculated that of the 78 Asian elephants born in captivity in North America between 1978 and 2007 , 19 are known to have died of EEHV , and five more were successfully treated with antiviral medication . 
