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.

The reproductive biology of Clarias ebriensis, C. agboyiensis, C. macromystax and C. buthupogon was investigated over a period of 32 months in Anambra River basin, Nigeria .

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Oviposition, fecundity and development of Dermestes maculatus in Clarias ebriensis with different moisture contents (14%, 36%, 41%, 56%, 66%, 73%, 77%) were investigated from January to April, 2003. Catfish of different moisture content and a pair of male and female D. maculatus constituted a treatment and each of the seven treatments was replicated thrice. The treatment with fish of 14% moisture content served as the control. Generally, the pre-oviposition period, egg incubation period, oviposition peak, percentage number of eggs hatching to larvae, duration of larval emergence, larval developmental period and duration of pupal emergence were all moisture-dependent. At 29 0 C and 58% RH, fecundity ranged from 54-598 eggs. The eggs measured 3.38±0.44 mm in length. The larvae had five larval instars which measured 3 28±0.71, 6.06±0.82, 8.04±0.75, 10.83±0.97 and 13.0±0.29 mm in length respectively. Larval developmental period was 16-23 days and larvae fed voraciously and bored into the flesh and head capsule of fish. Pupae measured 7.65±0.29 mm in length and adults emerged from. > 50% of pupae in all treatments. Total developmental period was 59 days. r .

Baseline information on the parasites of frequently caught species of the characids namely Hydrocynus vittatus, Alestes baremoze, Brycinus macrolepidotus and Brycinus leuciscus was investigated in Anambra River from August 2004 to July 2005. The parasites recovered were the Myxosporid, Myxobolus sp (Protozoa), Polyopistocotylids, Diplozoon ghanense and Neodipolzoon polycotyleus (Monogeneans), the Caryophyllid Caryophylleus sp (Cestoda) and Rhabdochona sp (Nematoda). The prevalence of Caryophylleus sp in B. macrolepidotus (14.2%) and A. baremoze (8.1%) as well as Rhabdochon sp and Myxobolus sp in H. vittatus (9.6% and 7.8% respectively) was relatively high (>7.0%); while the other parasite species Myxobolus sp in B. leuciscus (2%), D. ghanense in B. macrolepidotus (1.9%) and N. polycotyleus in A. baremoze (1.9%) had a much lower prevalence (2.7%). Distribution of parasites was clearly seasonal. Dissolved oxygen (8.0-14.0) mg l )1 and pH (5.5-7.0) influenced the occurrence of the parasites whereas temperature (20.1-27.5 DC) showed no much effect. Résumé Les informations de référence sur les parasites des espèces fréquemment capturées de Characidés Hydrocynus vittatus, Alestes baremoze, Brycinus macrolepidotus et Brycinus leuciscus ont été étudiées dans la rivière Anambra entre aoû t 2004 et juillet 2005. Les parasites retrouvés sont le Myxosporidé, Myxobolus sp. (Protozoaire), les Polyopistocotylidés, Diplozoon ghanense et Neodipolzoon polycotyleus (Monogènes), les Caryophyllidés Caryophylleus sp. (Cestodes) et Rhabdochona sp. (Nématodes). La prévalence de Caryophylleus sp. chez B. macrolepidotus (14,2%) et A. baremoze (8,1%) ainsi que de Rhabdochon sp. et Myxobolus sp. chez H. vittatus (9,6% et 7,8% respectivement) était relativement forte (>7,0%), alors que les autres espèces de parasites, Myxobolus sp. chez B. leuciscus (2%), Dipolzoon ghanense chez B. macrolepidotus (1,9%) et Neodiplozoon polycotyleus chez A. baremoze (1,9%) avaient une prévalence beaucoup plus faible (2,7%). La distribution des parasites était nettement saisonnière. L'oxygène dissous (8,0-14,0 mg ⁄ l) et le pH (5,5-7,0) influençaient l'occurrence des parasites alors que la température (20,1-27,5°C) n'avait pas beaucoup d'effets.