Prevalence and Mean Intensity of Myxobolus spp. Parasitizing Oreochromis niloticus in Cameroon

Oreochromis niloticus, being one of the most commonly cultured fish on earth constitutes a favorable biotope for myxosporidia. This study provides information concerning the prevalence and mean intensity of Myxobolus species recorded in the kidney and spleen of O. niloticus. O. niloticus were sampled in farming ponds at Bamendou in Cameroon. Classic methods concerning fishing, fish autopsy and search of Myxosporidia were used. Prevalence and mean intensity was calculated. Data analysis based on the chi-square test, Kruskal-Wallis H test and Mann-Whitney U test was done. The study revealed the presence of six Myxobolus species in the kidney and spleen of O. niloticus. All parasites species appeared frequent while their mean intensity was low or very low. The occurrence of M. fotoi was statistically lower (P < 0.05) in the kidney’s anterior portion while the mean intensity of M. agolus was statistically (P < 0.01) higher in the anterior portion of the spleen. Myxobolus cichlidarum was not found in kidney of young fish and occurrence of M. agolus statistically increases (P < 0.05) with host age. Host sex has significant influence (P < 0.05) on: occurrence of M. agolus, M. fotoi, M. agolus, M. brachysporus and M. heterosporus; and mean intensity of M. fotoi. The study revealed that in O. niloticus, the kidney and spleen harboured the same parasites species and there were only few variations in occurrences and mean intensities of parasites species recorded as function of host organs, age and sex.