Review of a newly recognized disease of elephants caused by endotheliotropic herpesviruses

Abstract

There are two newly recognized herpesviruses that cause a fatal disease syndrome in elephants. They are known as the elephant endotheliotropic herpesviruses, of which one is fatal for Asian elephants (Elephas maximus) and the other for African elephants (Loxodonta africana) [Richman et al., Science 283:1171–1176, 1999a]. The disease syndrome affects predominantly young elephants and has been described in North America [Richman et al., J Wildl Dis 36:1–12, 2000], Europe [Richman et al., Verhandlangsbericht des 39 International Symposium uben Erkrankungen der Zoo und Wildtiere, Wien, 39:17–21, 1999b; Ossent et al., Vet Pathol 27:131–133, 1990], and Israel [Richman et al., Verhandlangsbericht des 39 International Symposium uben Erkrankungen der Zoo und Wildtiere, Wien, 39:17–21, 1999b]. The predominant clinical signs for both species include lethargy, edematous swellings of the head, neck, and thoracic limbs, oral ulceration, cyanosis of the tongue, and death of most elephants in 1–7 days [Richman et al., J Wildl Dis 36:1–12, 2000]. Three affected young Asian elephants recovered after a 3–4-week course of therapy with the anti-herpesvirus drug famciclovir [Richman et al., J Wildl Dis 36:1–12, 2000; Schmitt and Hardy, J Elephant Managers Assoc 9:103–4, 1998]. Additional reported herpesvirus-associated lesions in otherwise healthy elephants include localized skin papillomas in African elephants [Richman et al., Science 283:1171–1176, 1999a; Jacobson et al., J Am Vet Med Assoc 189:1075–8, 1986], proliferative vulval lymphoid patches in African elephants [Richman et al., Science 283:1171–1176, 1999a; Munson et al., J Zoo Wildl Med 26:353–8, 1995], and pulmonary nodules in African elephants [Richman et al., J Wildl Dis 36:1–12, 2000; McCulley et al., Onderstepoort J Vet Res 38:225–236, 1971]. Recent findings suggest that these localized herpesvirus-associated lesions in healthy African elephants may be one source of the herpesvirus that causes disseminated disease and death in the Asian species [Richman et al., Science 283:1171–1176, 1999a] and the African species [Richman et al., J Wildl Dis 36:1–12, 2000]. These findings have implications for management practices in facilities keeping both African and Asian elephants and in protecting natural elephant habitats from virulent forms of the virus. Zoo Biol 19:383–392, 2000. © 2000 Wiley-Liss, Inc.