Presentation on theme: "CLINICAL FASCIOLIASIS IN A HERD OF FREE-RANGING IMPALA (Aepyceros melampus) IN KISUMU IMPALA PARK, KENYA MUCHEMI, G.M. 1, MUNENE, E 2., MUNGAI, B.N. 3."— Presentation transcript:
CLINICAL FASCIOLIASIS IN A HERD OF FREE-RANGING IMPALA (Aepyceros melampus) IN KISUMU IMPALA PARK, KENYA MUCHEMI, G.M. 1, MUNENE, E 2., MUNGAI, B.N. 3 and KIRIAMA, L 4 1University of Nairobi, Faculty of Veterinary Medicine, Dept. of Public Health Pharmacology and Toxicology, P.O Box 29053, NAIROBI. 2Institute of Primate Research, P.O. Box 24481, Karen, NAIROBI 3Kenya Medical Research Institute, P.O. Box 54840, NAIROBI 4Kenya Wildlife Service, P.O. Box 40241, NAIROBI
INTRODUCTION Kisumu Impala Park: Established in 1971 to provide sanctuary to the Impala antelopes that were freely ranging in Kisumu Town and its suburbs. The animals were facing habitat threats from human settlements and being knocked down by vehicles as they crossed roads. Kisumu Impala Park borders Kisumu Town to the East and Lake Victoria to the West. The antelopes drink either from the marshy areas around the lake shores or drainage channels that empty into the lake. There were 35 Impala comprising adult males, females and their young at the time of this investigation.
Literature Review ■ Diseases caused by Liver flukes (Fasciola) and gastrointestinal or stomach flukes (paramphistomes) lead to major economic losses in cattle, buffaloes, sheep and goats. ■ Estimated that more than 300 million bovines and 250 million sheep are exposed to the parasites worldwide causing losses amounting to over US$ 3 billion per year (FAO Report, 1994). ■ Wild animals (antelopes, other wild ruminants, zebra, rabbits and other herbivorous mammals) may serve as hosts and reservoirs for pasture contamination. ■ Humans can also be infected if they consume vegetables from naturally contaminated creeks.
Fascioliasis in Kisumu Impala Park ■ The Impala antelopes were observed to be in poor body condition with exposed rib cages and rough hair coats. ■ There was recent history of high mortality of young fawns and neonates and intermittent diarrhea in the adult animals. ■ This was despite the fact that the semi-tame antelopes were routinely dewormed for nematode parasites.
Materials and Methods ■ A preliminary survey of the impala grazing range was carried out during which three (3) fresh well formed faecal samples were collected along the grazing trails. ■ The samples were preserved in 70% alcohol and transported to the laboratory where they were analyzed using the formol-ether faecal concentration method (Munene et al, 1998)
Snail Survey in Drainage Channels A snail survey of the drainage channels was carried out and the following snail species collected: Biomphalaria sudanica species 96 Lymnaea natalenis 28 Bulinus species 6 Melanoides tuberculata 4 Ceratophallus species 86
Results ■All three (3) samples were found to be heavily infected with Fasciola gigantica and Fasciolopsis buskii eggs. No other nematode parasites ova were observed. ■The snail species were screened for cercariae shedding under natural daylight and the following results obtained. - Biomphalaria and Bulius species – negative for mammalian schistome cercariae - Lymnaea natalensis – negative (This snail is presumed to be the intermediate host for both Fasciola gigantica and Fasciola hepatica).
Treatment ■ The animals were preconditioned by feeding regularly with dairy meal for five days. This provided an opportunity to condition them to a feeding routine and closer observation before treatment. ■ For treatment 10 boluses of Nilzan (R) (each bolus contains 1.0 gm levamisole and 1.4 gm oxyclozanide) were pulverized and thoroughly mixed with the dairy meal.
Post Treatment Observation ■ There was remarkable improvement in the whole herd one month after treatment. ■ Their body conditions improved, the hair coats became smooth and the animals were more active and with bright demeanor. ■ The intermittent diarrhea stopped and gradual decline in fawn mortality was observed within three months.
Follow up Sampling ■ A repeat collection of faecal samples from the impala grazing range yielded negative results ■ Except from one chronically lame female which had Fasciola gigantica and unidentified strongyle eggs. ■ This was possibly because she was unable to access the feed used in the previous treatment. She was individually isolated and treated as above and showed remarkable improvement.
Discussion ■ Although results of Lymnaea natalensis snail screening were negative for cercariae -- does not exclude them from the transmission of Fascioliasis in the park. ■ Many Factors determine cercariae shedding -- stage of the life cycle. --the source of the infective snails ■ Report highlights the fact contrary to belief that free-ranging wild animals have developed mechanisms to cope with parasitic infections There are situations that can lead to serious clinical gastrointestinal infections!