Observations on the biology of Postharmostomum ntowi Hodasi, 1967 (Trematoda: Brachylaimidae) based on intermediate and definitive hosts found in Nigeria

Following the recovery of the metacercariae of a brachylaimid trematode from the rectum of the frog Amnirana galamensis from Ase in Delta State, Nigeria, we investigated the land snails in the locality to establish their roles in the life cycle of the parasite. Of the four land snails investigated from Ase (Limicolaria aurora, Archachatina marginata, A. papyracea, and Thapsia oscitans), and a Limicolaria sp. from Tombia (Bayelsa State), four harboured larval stages of the bracylaimid. Only L. aurora and the Limicolaria sp. harboured cercariogenous sporocysts and are therefore presumed to serve as the first intermediate hosts of the parasite. Metacercariae were recovered from the Limicolaria spp. and the Archachatina spp. and so serve as the second intermediate hosts. No larval brachylaimids were recovered from T. oscitans. Metacercariae from L. aurora and A. papyracea were cultured in vivo in 14 days old chicks of Gallus gallus domesticus. Parasites recovered from the experimental hosts 7, 14, 21 and 28 days post-infection, showed progressive development of the parasite with the full maturity attained by the 28^th day post-infection. Adult parasites recovered from the experimental birds and from free range chicken purchased from Ase and Tombia showed that the brachylaimid infecting these birds was Postharmostomum ntowi, a parasite previously reported in domestic chicken in Ghana. There is need to investigate the host range of the parasite in Nigeria as this trematode is also known to infect the Guinea fowl in Ghana.