The Possible Snail Intermediate Hosts of Dicrocoelium Hospes in Nigeria

Fashuyi S. A., G. O. Adeoye: The Possible Snail Intermediate Hosts of Dicrocoelium hospes in Nigeria. Acta vet. Brno, 55, 1986: 85 -88. Limicolaria /lammea. L. striatula and Lamellaxis gracilis were experimentally infected with larval stages of Dicrocoelium hospes after exposure to embryonated eggs. Limicolaria proved to be more suitable, showing higher infection rates, more mature cercariae and retaining infections longer. The potential for Lamellaxis as a natural host seems higher because it is known to occur in both rain forest and drier savanna grassland where most cattle are pastured. Limicolaria is essentially a rain forest snail. Laboratory infection. cercariae. larvae. sporocysts. trematodes. There are records of Dicrocoelium hospes infections in cattle in Nigeria !1nd several other countries. Such reports include those of Graber and Oumatie (1964), Odei (1966), Williams (1969), Mahlau (1970), Kajubiri et al. (1977) and Obiamiwe (1977). Studies of its life cycle including the molluscan hosts are very sketchy and speculative in most cases. This situation contrasts sharply with Dicrocoelium dendriticum. a closely related species where almost thirty snail species and several arthropods were listed by Soulsby (1965) as intermediate hosts in Europe, America, Asia and North Mrica. Limicolaria and Achatina were suggested as possible snail hosts of D. hospes in Ghana (Odei 1966) while Bourgat et al. (1975) found larval stages of the trematode from Limicolaria/lammea. L. striatula and L. aurora collected from grazing fields in Togo. In Sierra Leone, however, Asanji (1976) failed to infect experimentally any of these snails, although the country shares similar geographical and ecological features with Ghana and Togo. It is therefore important to establish the hosts of the fluke in Nigeria for a good understanding of its epizootiology. Materials and Methods Eggs of D. hospes were recovered from the gall bladders of infected cattle or teased out of the uterus of adult worms. They were incubated to full embryonation using the method of Fashuyi (1984). Samples of Limicolaria /lammea. L. striatula. an unidentified Limicolaria sp. and young Achatina sp. were collected from the Biological Garden of the University of Lagos while colonies of Lamellaxis gracilis were raised in the laboratory. Adult Achatina sp. was purchased from open markets in Lagos. Several snails from each sample collected from the Biological Garden were dissected and examined for trematode infection. Exposure of snails to infection was carried out by isolating them in groups of five in plastic cans containing food mixed with over one hundred fully embryonated eggs for 48 hours on each occasion. Seven days after exposure, 1 2 snails of each type were dissected daily and examined * Present address: Department of Biological Sciences Federal University of Technology Akure, Ondo State, Nigeria .1