SEROSURVEY FOR SELECTED VIRAL DISEASES AND DEMOGRAPHY OF AFRICAN WILDDOGS IN TANZANIA

African wild dogs (Lycaon pictus) are endangered, with only 3,000-5,00 0 remaining in the wild. It is believed that wild dogs are unusually v ulnerable to viral diseases, particularly rabies and canine distemper (CDV). However, canine distemper has been confirmed by laboratory diag nosis in only one free-living wild dog. The 43,000 km(2) Selous Game R eserve (SGR; Tanzania) holds approximately 900 adult wild dogs. In a s tudy area of 2,600 km(2), the population maintained high density (grea ter than or equal to 1 dog/20.5 km(2)) from 1991 to 1996. The populati on was stable, varying 18% below and 9% above the mean density over th e 6-yr period. Serum samples (n = 22) collected over 3 yr showed that most individuals were exposed to CDV (59%: 95% confidence interval = 4 3-76% seropositive) and canine parvovirus (68%: 95% CI = 54-81% seropo sitive), although none were seropositive for rabies (0%: 95% CI = 0-17 %). CDV titers were positively related to age, with no seropositive do gs younger than 1.9 yr. At least five of 13 dogs positive for CDV sero converted during the study. Dogs with high CDV titers did not survive better in the years after sampling (mean survival +/- SE for those tha t died = 638 +/- 92 days,). Variation in mean litter size was inversel y related to CPV exposure in the SGR and elsewhere. Annual mortality r ates were low in comparison to other populations for all age classes ( pups: 31 +/- 8%, n = 127, yearlings: 22 +/- 10%, n = 93, adults: 20 +/ - 6%, n = 235). Annual mortality rates fluctuated little between 1992 and 1996. These data show that wild dog populations, like those of oth er canids, can remain stable and demographically healthy despite expos ure to CDV and CPV.