Abstract
Four Hundred (400) samples of Chrysichthys nigrodigitatus were examined for Henneguya chrysichthys using methods described for gills examination and haemopatholgy. 135 (33.8%), Chrysichthys nigrodigitatus were infected by Henneguya chrysichthys. The infection was seen on the gill filament as an oval cyst somewhat white and visible to the naked eyes. 27 (20%), 88 (65.2%) and 20 (14.8%) were recorded for low, moderate and high infection respectively. Lowest (22.7%) and highest (45.5%) prevalence were observed in the months of December and May respectively. Prevalence was higher in wet season (54.1%) than in dry season (45.9,%) More female fish (51.1%) had infection than the male fish (48.8%).Haematological examination revealed changes in blood cell count, erythrocyte sedimentary rate and Haematocrit counts. Hemoglobin (per 100mI) remains the same in infected and uninfected fish. Erythrccyte count (X106/mm3) was 1.28�1.11 and 1.0�0.53 while leucocytes count (per mm3) was 2.36�1.0 and 43200�0.60 foruninfected and infected fish respectively. Leucocytosis in infected fish was marked by lymphocytes (35.11�0.32), Neutrophils (26.32�1.65), plasmocytes (23.06�0.9 1) and monocytes (16.0�0.21). Corresponding values of these classes of Leucocytes are 7.38�0.69, 21,86 � 1.71, 6.90� 1.12 and 7.24� 1.09 respectively in uninfected fish. Infected fish appeared weak and emaciated.