Seasonal pattern of bovine fasciolosis in the Kafue and Zambezi catchment areas of Zambia.

In order to establish seasonality of bovine fasciolosis in the Southern province of Zambia, 288 cattle were examined at slaughter at Turnpike slaughter slab for 1 year. The examination involved liver inspection and coprological examination. Liver condemnation rates were relatively high at the beginning of both the cold dry season and the rainy season (May/June and December, respectively). All cattle, regardless of age, had higher fluke abundances in the post-rainy season (39.1% young and 42.1% adult) while the lowest rates were in the hot dry season (13.3% young and 14.3% adult). On coprological examination, the highest abundance was in the post-rainy season (45.0%) and the lowest in the cold dry season (24.9%). From November (end of dry season) to February/March (end of rains), more fluke eggs were found than in any other period. The distribution of fluke eggs was significantly different (p<0.001) among the four seasons. Identified associations were: egg counts were highest in post-rainy (mean abundance=146) and lowest in cold dry season (mean abundance=118) at 95% confidence (CI 0.64-1.25). Differences in abundance observed according to origin, sex and age of cattle were not significant on both methods. Based on these results, it may be concluded that Fasciola gigantica was present throughout the year in cattle in Zambia but the abundance was highest in the post-rainy season and lowest in the cold dry season.