Hematocrit values (PCV) of infected and unninfected wild fish species were investigated in 11 months period (covering early rainy, late rainy, early dry and late dry Seasons) from 10 locations in Sokoto Kebbi and Zamfara States, in semiarid region of Nigeria. Interseasonal difference in prevalence was observed (P<0.05), while inter and intraseasonal reduction in hematocrit were observed from eleven locations. Only PCV of Clarias gariepinus and Synodontis nigrata from Lugu and Rabah locations showed statistical significance (P<0.05) respectively. Difference between PCV of infected and uninfected Tilapia zilli and Mormyrus rume were not significant (P> 0.05). The significant difference in PCV of infected C. gariepinus and S. nigrata, suggested manifestation of pathologic effect of piscine trypanosomes. Significant values were also observed among uninfected fish from few locations, indicating other factors associated with anemia in those locations apart from trypanosomes. The seasonal effect in PCV is relative to water volume and population of leeches.
