Abstract

Alveolar echinococcosis (AE) was diagnosed in seven lowland gorillas (Gorilla g. gorilla) originating from a Swiss zoo from 1999–2011. Four gorillas died of the disease.³ Three clinical cases were diagnosed using imaging techniques and serology.^2,5 These asymptomatic individuals are continuously treated with albendazole (Valbazen 10%, Pfizer AG, CH-8052 Zurich Switzerland). No cases have occurred in the orangutans (Pongo pygmaeus), but one chimpanzee (Pan troglodytes) was tested serologically positive. All three species of the great apes are housed under similar conditions and direct contact to the main host of Echinococcus multilocularis in Europe, the red fox (Vulpes vulpes), can be excluded. The incubation period of the disease in humans is 5–15 years and infection may also remain undetected in gorillas for years. It is assumed that food or other material which was brought into the enclosure was contaminated with fox feces and infected the gorillas. Possible sources were evaluated, but no specific cause was identified. Preventive sanitary measures for the preparation and storage of introduced food and materials including treatment with low heat may help reduce AE infections.⁴ It is hypothetized that lowland gorillas run an increased risk of becoming aberrant hosts and of developing AE as compared with other great ape species or humans. Rabies control programs have increased the red fox population in rural and urban areas in Central Europe and up to 50% of the red foxes are known to host Echinococcus multilocularis.¹ Therefore, zoos in Europe that keep gorillas have to be aware of the disease and should take preventive actions.

Literature Cited

1.  Eckert, J., and P. Deplazes 1999. Alveolar echinococcosis in humans: The current situation in central Europe and the needs for countermeasures. Parasitology Today 15:315–319.

2.  Hoby, S., B. Mengiardi, and C. Wenker 2009. Computertomografie bei einem Gorilla mit alveolärer Echinokokkose. Arbeitstagung der Zootierärzte im deutschsprachigen Raum 29:90–94.

3.  Rehmann, P., A. Gröne, A. Lawrenz, O. Pagan, B. Gottstein, and L.N. Bacciarini 2003. Echinococcus multilocularis in two lowland gorillas (Gorilla g. Gorilla). Journal of Comparative Pathology 129:85–88.

4.  Veit, P., B. Bilger, V. Schad, J. Schäfer, W. Frank, and R. Lucius 1995. Influence of environmental factors on the infectivity of Echinococcus multilocularis eggs. Parasitology 110:79–86.

5.  Wenker, C., S. Hoby, and J. Völlm 2008. Alveolar echinococcosis—captive lowland gorillas at risk? Proceedings of the European Association of Zoo and Wildlife Veterinarians 7:45–48.