Endo-parasitic helminthes of four mormyrid species (Osteichthyes: Mormyridae) from a West African flood river system.

Mormyrus rume rume, Hyperopisus bebe bebe, Campylomormyrus tamandua and Gnathonemus petersii sampled from the Anambra river with a fleet of gill nets, traps and hook and line were examined for endo-parasitic helminthes from October 2005 to September 2006. Recovered helminthes were Rhadinorhynchus horridus from the intestine of H. bebe bebe and G. petersii; Procamallanus laeviconchus from the stomach of M. rume rume and C. tamandua; Spinitectus mormyri from the stomach of M. rume rume; Contracaecum sp. from the coelom of H. bebe bebe, G. petersii and C. tamandua, whereas an unidentified cestode infected the intestine of all the mormyrids. G. petersii constitutes a new host record for R. horridus; M. rume rume for S. mormyri and M. rume rume and C. tamandua for P. laeviconchus. In cases of mixed infection the parasites occupied their preferred habitats. The overall prevalence of the endo-parasites in the fish hosts was 41.9%, which is within the range (< 50%) typical of southern Nigerian freshwater lotic habitats. Prevalence, mean intensity and mean abundance of R. horridus in its host fishes were higher in the dry (October/November-March) than the rainy season (April-September/October); in the nematodes (P. laeviconchus, S. mormyri and Contracaecum) the reverse was the case, whereas no definite pattern was exhibited by the unidentified cestode. P. laeviconchus appeared reddish from engorgement of blood but no damage was evident at the point of attachment. Local inflammation where R. horridus was attached to the mucosa of the intestine was not considered severe. R. horridus and P. laeviconchus are probably the most important parasites of the mormyrids in terms of fishery management in the Anambra river system.

Investigation into the prevalence of urinary schistosomiasis in the Agulu Lake area of Anambra State, Nigeria.

In epidemiological surveys for urinary schistosomiasis caused by Schistosoma haematobium in communities around Agulu Lake, Anambra State, Nigeria, between 1990 and 1992, the infection was found to be endemic in the area, especially in three towns: Nri, Agulu, and Adazi Nnukwu. The prevalence rates varied between these communities and with the year. Inter-town prevalence rates ranged from 5.96% to 54.00%. Intravillage prevalence rates ranged between 5.50% to 96.43%. Prevalence rates were highest in villages very close to Agulu lake. There was no significant difference in prevalence between the schools. Host age, but not sex, was found to play a significant role in prevalence and intensity of infection. There was also a strong correlation between visible haematuria and egg count per 10 ml urine, but eggs could be isolated in urine samples of different shades of coloration. Analysis of incidence of infection in these communities shows that Schistosoma haematobium incidence is high in Nri (55.17%) and low at Adazi Nnukwu (5.26%). Both Bulinus globosus and B. truncatus were found in the lake and both shed mammalian bifid schistosome cercariae.