Elephant endotheliotropic herpesvirus 2 infection in 5 African elephants (Loxodonta africana) at multiple North American zoological institutions.

Objective: To acknowledge that elephant endotheliotropic herpesvirus (EEHV) is a well-recognized major threat to Asian elephants (Elephas maximus) and can cause acute and often fatal hemorrhagic disease (HD). Historically, EEHV-HD has been less frequently identified in African elephants (Loxodonta africana). This case series describes 5 recent cases of EEHV2 infection in African elephants within managed care at 5 North American institutions.

Animals: 5 African elephants (L africana).

Clinical presentation: The cases involved 4-, 7-, and 10-year-old males that died despite receiving aggressive medical therapy and 4- and 14-year-old females that survived. Clinical signs included lethargy, decreased appetite, lameness, changes in behavior and sleep patterns, multifocal hemorrhages, edema, and lingual cyanosis. Hematologic changes included decreased total WBC counts, monocytes, and platelets and the presence of immature band heterophils.

Results: EEHV2-specific serostatus for the 3 lethal cases suggests that they were seronegative for EEHV2 and succumbed to a primary infection, whereas the fourth and fifth cases were noted to be seropositive for EEHV2 and survived. This series documents the latest reports of clinical diseases and fatalities associated with EEHV2 in African elephants and significantly adds to the known number of lethal EEHV-HD cases within the population.

Clinical relevance: This series provides additional evidence that negative serostatus against an EEHV type causing disease is observed in African elephants, as well as Asian elephants, and highlights the importance of routine monitoring for serostatus within African elephant herds. Furthermore, these cases provide new data suggesting that EEHV2, in addition to EEHV3, is a significant pathogen that can affect African elephant populations.