Metazoan parasites, condition factor and hepato-somatic index of amphibians from oil-producing communities in Rivers State, Nigeria

Abstract

Amphibians were collected from six locations in Rivers State, Nigeria, using search and capture techniques, and purchases from local markets. The locations were Okwale and Teka Sogho in Ogoniland, Akabuka in Omoku, Omofo in Ndele, Rumuche in Emohua and Ikata in Ahoada East. Amphibians were euthanized; body mass, liver mass, and snout-vent length of each specimen were taken after which they were examined for helminth endoparasites in the gastrointestinal tract, lungs, liver, urinary bladder and body cavity. Prevalence and mean intensity of parasite infections were computed; body condition factor and hepato somatic index of amphibians were also computed. Amphibian species encountered included Sclerophrys spp., Hoplobatrachus occipitalis, Silurana tropicalis, Hymenochirus sp., and Ptychadena species. Parasite species recovered were trematodes (Prosotocus exovitellosus, Ganeo africana, Diplodiscus fischthalicus, Metahaematoloechus exoterorchis, Mesocoelium monodi, Mesocoelium sp.), cestodes (Baerietta jaegerskioeldii), acanthocephalan cysthacanths, pentastomids (Raillietiella sp.), monogeneans (Polystoma aeschlimanni, P. baeri and P. pricei), and nematodes (Amplicaecum africanum, Ascaridida larva, Batracocamallanus siluranae, Chabaudus leberrei, Cosmocerca ornata, Oswaldocruzia hoepplii, Rhabdias africanus, Rhabdias sp. 1 and 2. Hymenochirus sp. is reported as a new host for C. leberrei. Parasite community structure closely followed that of the hosts. Parasites were generally less prevalent in hosts from Ogoni and Omoku. Condition factor of all amphibians examined were greater than 1. Higher HSI values were recorded in Hymenochirus sp. from Akabuka Omoku indicating higher stress level in that location.

Keywords: Helminth; health status; petroleum industry; anthropogenic change; habitat alteration.