Treponema infection associated with genital ulceration in wild baboons.

The authors describe genital alterations and detailed histologic findings in baboons naturally infected with Treponema pallidum. The disease causes moderate to severe genital ulcerations in a population of olive baboons (Papio hamadryas anubis) at Lake Manyara National Park in Tanzania. In a field survey in 2007, 63 individuals of all age classes, both sexes, and different grades of infection were chemically immobilized and sampled. Histology and molecular biological tests were used to detect and identify the organism responsible: a strain similar to T pallidum ssp pertenue, the cause of yaws in humans. Although treponemal infections are not a new phenomenon in nonhuman primates, the infection described here appears to be strictly associated with the anogenital region and results in tissue alterations matching those found in human syphilis infections (caused by T pallidum ssp pallidum), despite the causative pathogen's greater genetic similarity to human yaws-causing strains.

Glossina dynamics in and around the sleeping sickness endemic Serengeti ecosystem of northwestern Tanzania.

We investigated the dynamics of Glossina spp. and their role in the transmission of trypanosomiasis in the sleeping sickness endemic Serengeti ecosystem, northwestern Tanzania. The study investigated Glossina species composition, trap density, trypanosome infection rates, and the diversity of trypanosomes infecting the species. Tsetse were trapped using monopyramidal traps in the mornings between 06:00 to 11:00 and transported to the veterinary laboratory in Serengeti National Park where they were sorted into species and sex, and dissected microscopically to determine trypanosome infection rates. Age estimation of dissected flies was also conducted concurrently. Tsetse samples positive for trypanosomes were subjected to PCR to determine the identity of the detected trypanosomes. Out of 2,519 tsetse trapped, 1,522 (60.42%) were G. swynnertoni, 993 (39.42%) were G. pallidipes, three (0.12%) were G. m. morsitans, and one (0.04%) was G. brevipalpis. The trap density for G. swynnertoni was between 1.40 and 14.17 while that of G. pallidipes was between 0.23 and 9.70. Out of 677 dissected G. swynnertoni, 63 flies (9.3%) were infected, of which 62 (98.4%) were females. A total of 199 G. pallidipes was also dissected but none was infected. There was no significant difference between the apparent densities of G. swynnertoni compared to that of G. pallidipes (t = 1.42, p = 0.18). Molecular characterization of the 63 infected G. swynnertoni midguts showed that 19 (30.2%) were trypanosomes associated with suid animals while nine (14.3%) were trypanosomes associated with bovid animals and five samples (7.9%) had T. brucei s.l genomic DNA. Thirty (47.6%) tsetse samples could not be identified. Subsequent PCR to differentiate between T. b. brucei and T. b. rhodesiense showed that all five samples that contained the T. brucei s.l genomic DNA were positive for the SRA molecular marker indicating that they were T. b. rhodesiense. These results indicate that G. swynnertoni plays a major role in the transmission of trypaniosomiasis in the area and that deliberate and sustainable control measures should be initiated and scaled up.

Re-infection of wildlife populations with rinderpest virus on the periphery of the Somali ecosystem in East Africa.

We report surveillance for rinderpest virus in wildlife populations in three major ecosystems of East Africa: Great Rift Valley, Somali and Tsavo from 1994 to 2003. Three hundred and eighty wild animals were sampled for detection of rinderpest virus, antigen or genome and 1133 sampled for antibody in sera from Kenya, Uganda, Ethiopia and Tanzania from 20 species. This was done modifying for wildlife the internationally recommended standards for rinderpest investigation and diagnosis in livestock. The animals were selected according to susceptibility and preference given to gregarious species, and populations were selected according to abundance, availability and association with livestock. Rinderpest virus, antigen and/or genome were detected in Kenya; within Tsavo, Nairobi and Meru National Parks. Serological results from 864 animals (of which 65% were buffalo) from the region were selected as unequivocal; showing the temporal and spatial aspects of past epidemics. Recent infection has been only in or peripheral to the Somali ecosystem (in Kenya). Our evidence supports the hypothesis that wildlife is not important in the long-term maintenance of rinderpest and that wildlife are infected sporadically most likely from a cattle source, although this needs to be proven in the Somali ecosystem. Wildlife will continue to be a key to monitoring the remaining virus circulation in Africa.

Knowledge, attitudes and practices on tsetse and sleeping sickness among communities living in and around Serengeti National Park, Tanzania.

A study was undertaken to investigate knowledge, attitudes and practices about sleeping sickness (human African trypanosomiasis) among communities living in and around Serengeti National Park (SENAPA). Structured questionnaires were administered to a total of 1490 consenting participants. Of the respondents, 924 (62%) knew sleeping sickness, and 807 (87.3%) knew the right place to seek healthcare. Of 924 who knew sleeping sickness, 386 (42%) said the disease was present in the areas they live. Most respondents (85.4%) knew that sleeping sickness infections were acquired in the bush and forest. The most common (69.3%) sources of information about sleeping sickness were relatives and friends. Symptoms of sleeping sickness mentioned included abnormal sleep (45.2%), fever (35.3%), body malaise (14.5%), headache (7.6%) and lymph node enlargement (6.1%). Of 1490 people interviewed 90.4% knew tsetse flies and 89.8% had been bitten by tsetse flies. The majority (86.6%) of the respondents knew that sleeping sickness is transmitted through a tsetse bite. Activities that exposed people to tsetse bites included working in tsetse infested bushes/forests, grazing livestock in tsetse infested areas and hunting game animals. In conclusion, communities living in and around SENAPA were knowledgeable about tsetse and sleeping sickness. The communities can thus understand and support community based tsetse and sleeping sickness control programmes to ensure success.

Tuberculosis in Tanzanian wildlife.

Bovine tuberculosis, caused by Mycobacterium bovis, is a pathogen of growing concern in free-ranging wildlife in Africa, but little is known about the disease in Tanzanian wildlife. Here, we report the infection status of Mycobacterium bovis in a range of wildlife species sampled from protected areas in northern Tanzania. M. bovis was isolated from 11.1% (2/18) migratory wildebeest (Connochaetes taurinus) and 11.1% (1/9) topi (Damaliscus lunatus) sampled systematically in 2000 during a meat cropping program in the Serengeti ecosystem, and from one wildebeest and one lesser kudu (Tragelaphus imberbis) killed by sport hunters adjacent to Tarangire National Park. A tuberculosis antibody enzyme immunoassay (EIA) was used to screen serum samples collected from 184 Serengeti lions (Panthera leo) and 19 lions from Ngorongoro Crater sampled between 1985 and 2000. Samples from 212 ungulates collected throughout the protected area network between 1998 and 2001 also were tested by EIA. Serological assays detected antibodies to M. bovis in 4% of Serengeti lions; one positive lion was sampled in 1984. Antibodies were detected in one of 17 (6%) buffalo (Syncerus caffer) in Tarangire and one of 41 (2%) wildebeest in the Serengeti. This study confirms for the first time the presence of bovine tuberculosis in wildlife of northern Tanzania, but further investigation is required to assess the impact on wildlife populations and the role of different wildlife species in maintenance and transmission.

A dog rabies vaccination campaign in rural Africa: impact on the incidence of dog rabies and human dog-bite injuries.

Despite the availability of safe and effective rabies vaccines, the incidence of dog rabies has been increasing throughout much of sub-Saharan Africa. Here we describe a vaccination strategy that has resulted in successful control of rabies in a rural dog population of Northwestern Tanzania. From October 1996 to February 2001, four central-point dog vaccination campaigns were conducted in villages within Serengeti District with a mean interval between campaigns of 338, 319 and 456 days. Vaccination coverage of the dog population was estimated from household questionnaires as 64.5, 61.1, 70.6 and 73.7% following each of the four campaigns, respectively. The incidence of dog rabies declined significantly in Serengeti District falling by 70% after the first campaign and by 97% after the second campaign. Over the same period, the incidence of dog rabies did not differ significantly in unvaccinated control villages of Musoma District. The incidence of human bite injuries from suspected rabid dogs declined significantly in Serengeti District after dog vaccination but not in adjacent unvaccinated districts. Vaccination of 60-70% of dogs has been sufficient to control dog rabies in this area and to significantly reduce demand for human post-exposure rabies treatment. Dog-bite injuries can provide a valuable and accessible source of data for surveillance in countries where case incidence data are difficult to obtain.

Antibodies to some pathogenic agents in free-living wild species in Tanzania.

A total of 535 sera from eight species of wildlife were collected from different game areas in Tanzania between 1987 and 1989. These sera were tested for antibodies against foot-and-mouth disease, bovine herpes virus types 1 and 2, lumpy skin disease, bovine viral diarrhoea, Akabane, bovine ephemeral fever, bluetongue, enzootic bovine leucosis, African horse sickness and African swine fever viruses and Brucella abortus based on the expected species susceptibility. Sera from buffalo Syncerus caffer, wildebeest Connochaetes taurinus and topi Damaliscus korrigum contained antibodies against the majority of the pathogens tested. Antibodies to fewer pathogens were detected in sera from the other species. No antibodies to lumpy skin disease virus were detected in any of the sera examined. African horse sickness antibodies were detected in sera from Zebra and African swine fever antibodies were detected in wart hog. The occurrence of antibodies to these agents suggests that wild species act as reservoirs of infection for some of these pathogens. However, until the susceptibility of individual species is proven by isolation of the aetiological agents their role must remain speculative.

A serological survey of rinderpest antibody in wildlife and sheep and goats in northern Tanzania.

An extensive serological survey for rinderpest antibody in wildlife, principally buffalo (Syncerus caffer), and sheep and goats has been undertaken in the previously endemic region of Northern Tanzania to determine whether or not the virus has continued to cycle in susceptible species since the last occurrence of overt disease in 1982. The results show that infection but not disease has occurred at least until 1987 in buffalo in parts of the Serengeti National Park but not in the other game areas of Tanzania where samples were taken. Sero-positive sheep and goats were widely distributed and have been found in 10 of the 14 districts sampled but there have been no reports of disease. These findings bring into question the possibility of eradicating the disease from Africa and continuous annual monitoring of this and other similar ecological zones will be required.