Prevalence of stephanofilariasis in young Bos indicus cattle in northern Australia

Four consecutive annual calf crops of known genotype from a single property in northern Australia were examined for the presence of stephanofilarial lesions. The animals ranged in age from 60 to 348 days at the time of examination. Initial lesions of stephanofilariasis developed adjacent to the medial canthi of the eyes; animals as young as 69 days of age were found infected. In all years, prevalence of lesions increased with age for all genotypes, and was significantly lower in genotypes with higher Bos indicus content (P less than 0.01). Males had a higher prevalence of lesions than females in only one year, and in two of the years, dark-coloured animals had a higher prevalence of lesions than light-coloured ones.