PAPERS & ARTICLES Scabies in free-ranging mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda G. KALEMA-ZIKUSOKA, R. A. KOCK, E. J. MACFIE Between August and December 1996, there was an outbreak of a debilitating skin disease attributed to Sarcoptes scabiei infection in mountain gorillas (Gorilla beringei beringe,) in Bwindi Impenetrable National Park in Uganda. All four members of a gorilla group which had been habituated to tourists were clinically affected; the infant male gorilla was most severely affected and died, the juvenile male showed serious manifestations of the disease and the two adult animals showed milder signs. The three older animals recovered after a single intramuscular dose of ivermectin. S scabiei mites were observed on skin scrapings and biopsies taken while the juvenile was immobilised and in postmortem samples taken from the infant. The clinical signs did not recur during the following year, and no other gorilla groups in the park were observed to be clinically affected. MOUNTAIN gorillas (Gorilla beringei beringei) are an endangered species, with only approximately 650 remaining in Rwanda, the Democratic Republic of Congo and Uganda. Approximately 290 gorillas live in Bwindi Impenetrable National Park, Uganda, where two of 28 gorilla groups have been habituated for tourism and one for behavioural research (McNeilage and others 1998). The policy adopted by the government agency responsible for gorilla health, the Uganda Wildlife Authority, limits any veterinary interven- tions to diseases caused by human beings or life-threatening conditions, to minimise the disturbance to the animals' nat- ural behaviour. Gorillas are considered to be susceptible to many human diseases because of their close genetic simi- larity and suspected naivety to most human pathogens (Ott- Joslin 1993, Osborn and Lowenstein 1998, Wallis and Rick Lee 1999). Intense efforts are made to prevent the trans- mission of disease between people and gorillas during the visits of tourists and in the course of research; they include limiting human approaches to more than 5 m, burying human excreta at least 30 cm deep, and restricting entry to clinically healthy visitors (Macfie 1992). Other measures include chasing gorillas from private land surrounding the park, especially when the gorillas are feeding on people's banana plants. Scabies or sarcoptic mange is a contagious skin disease caused by Sarcoptes scabiei mites, which are generally con- sidered host-specific, but can cause disease in other hosts. The pathogenesis of sarcoptic mange is well known (Soulsby 1982, Wall and Shearer 1997) and the disease has been recorded in a wide variety of species including human beings, and domestic and wild animals. Mange is becoming an important disease of free-ranging wildlife (Valenzuela and others 2000) and reported hosts in Africa include wild chimpanzees (Pan troglodytes schweinfurthii) (Pusey 1998, Wallis and Rick Lee 1999), and cheetahs (Acinonyx jubatus) (Mwanzia and others 1995). Scabies is said to be commonly diagnosed in people in the vicinity of Bwindi Park. The species of mite involved, the host's immune status and degree of exposure, the parasite burden and stressors are thought to influence the severity of the clinical disease (Soulsby 1982, Wall and Shearer 1997). This paper describes the management of an isolated outbreak of scabies in a free- ranging group of mountain gorillas which were habituated to visitors. The outbreak resulted in morbidity and mor- tality, but the clinical signs resolved after treatment. The implications for the health of people and gorillas are discussed. CASE REPORT Study area and invesfigation of the outbreak The outbreak occurred during the wet season of 1996 in Bwindi Impenetrable National Park, south-western Uganda, a tropical montane and lowland forest covering an area of 330 km2 and ranging in altitude from 1190 to 2607 m. Temperatures range from 7 to 15°C at night, to 20 to 27°C during the day. The affected gorilla group, known as the Katendegyere group, was ranging at 0.960 south longitude and 29.60 east latitude where gorillas were occupying the ground in thick, dense and mainly secondary forest, and there was a tourist site, Buhoma, adjacent to its range. Clinical history of the Katendegyere mountain gorilla tourist group At the beginning of 1996 the Katendegyere group had six mem- bers. However, in May, the lead silverback, Mugurusi, died of old age-related changes including renal and cardiac failure. After his death, a young silverback, Kalema, left the group. At the time of the disease outbreak, the group consisted of one adult male silverback, one adult female, one juvenile male and one infant male. The observers believed the group to be more stressed during tourist visits, possibly because the usual tourist groups of six people outnumbered the gorillas. In May 1996, the gorilla group crossed the border into the Democratic Republic of Congo and raided banana plants in an area where the local farmers have been reported to have rough skin. In August, the field staff reported that the Katendegyere gorillas were losing hair and developing white, scaly skin. The condition had never been observed in these animals since their habituation had begun in 1992. A health check was made by observing the gorillas at a distance of approximately 5 m with and without binoculars. The seven-month-old infant male had lost hair on its back and most of its body and was exceptionally pale and emaciated, but it was still alive and clung on to its mother. The infant was heard crying on sev- eral occasions, and may have been in discomfort. The juvenile male had lost hair on the back of his legs, and on his inner elbow and neck. The adult female in the group had also lost hair on the back of her legs and chest, where she carried her infant. The silverback male did not show any outward signs of disease, but appeared to be scratching more frequently than usual, as did the female and the juvenile. Immobilisation and anaesthesia of the juvenile gorilla On the basis of the clinical signs shown by the group it was Veterinary Record (2002) 150, 12-15 G. Kalema-Zikusoka, BVetMed, MRCVS, Veterinary Unit, Uganda Wildlife Authority, PO Box 3530, Kampala, Uganda R. A. Kock, MA, VetMB, MRCVS, Field Conservation and Consultancy Zoological Society of London, c/o OAU IBAR Pan African Programme for the Control of Epizootics, PO Box 30786, Nairobi, Kenya E. J. Macfie, DVM, MS, International Gorilla Conservation Programme, PO Box 10950, Kampala, Uganda Mrs Kalema-Zikusoka's present address is Environmental Medicine Consortium and Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, 4700 Hillsborough Street, Raleigh, North Carolina 27606, USA The Veterinary Record, January 5, 2002 1 2 group.bmj.com on March 14, 2013 - Published by veterinaryrecord.bmj.com Downloaded from