Abnormalities and virus-like particles in spermatozoa from bulls latently infected with bluetongue virus.

Abnormalities were commonly observed in spermatozoa, and bluetongue virus (BTV) was isolated from semen of 2 known BTV carrier bulls and 2 of 4 BTV seropositive field bulls. The spermatozoal abnormalities ranged from a small cavity between the acrosome and nucleus with some involvement of the nucleus, to an enlargement of the cavity accompanied by vesiculation that could affect the entire acrosome. Virus-like particles were occasionally observed in the affected spermatozoa, but were present in all samples. A positive relationship was found between infectivity of semen samples from BTV latently infected bulls and the observation of abnormalities and virus-like particles in the heads of affected spermatozoa.