Morphology of bluetongue virus-infected Aedes albopictus (C6/36) cell culture.

Morphological changes observed in bluetongue virus (BTV)-infected Aedes albopictus (C6/36) suspension cell culture at 28 C were compared to those observed in mammalian stationary cell culture at 37 C. The presence of cytoplasmic macrotubules, viroplasms and progeny virions was confirmed and appears to be the same as seen in mammalian cell culture. In addition progeny virions were observed budding from cell membranes where they appeared to acquire a lipoprotein envelope. Intranuclear macrotubules that are the same diameter as the cytoplasmic macrotubules were also seen. C6/36 cell culture is a model for gaining insight into BTV-replication in the insect host.

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.

Continuity of the dsRNA genome of bluetongue virus.

The duplex RNA genome of bluetongue virus, extracted under acidic conditions with sodium dodecyl sulfate and phenol, is an unfragmented continuous structure. Most genomes appeared as a rosette with 10 loops (genes) emanating from a central crescent- or doughnutshaped area. The genome has a mean length of ca. 10 µm which corresponds to a molecular weight of ca. 23 million.