Virus-like rods associated with salivary gland hyperplasia in tsetse, Glossina pallidipes.

Long, virus-like rods were discovered in hyperplastic salivary glands of Glossina pallidipes Austen from Kibwezi Forest (2 degrees 27' S, 37 degrees 55' E), Kenya. The glands were enlarged up to four times the normal diameter. This increase in size was due to a cellular proliferation of the glandular epithelial cells and hypertrophy of their nuclei and cytoplasm. Nuclear and cytoplasmic inclusions were present in the enlarged cells but were not found in cells of normal-sized glands. Electron microscopy revealed many virus-liked rods in the abnormal glands. Males with such glands were often completely sterile. Abnormal growth of the ovarioles was a significant feature of young females with hyperplastic glands. Both sexes of wild and laboratory-bred flies were found with enlarged glands. One way of transmission of the trait seems to be from mother to progeny.