Tumour induction by viruses isolated from Mansonia africana.

A group of viruses originally isolated from different pools of Mansonia africana induced 'tumours' in swiss albino mice when injected intraperitoneally, intracerebrally and intravenously. Tumours which developed in close proximity to points of initial inoculation were round, single or bilobular and usually appeared to adhere to underlying structures. Extracts of the tumours yielded similar tumours in freshly inoculated animals. Clarified extracts caused cytopathogenicity in cell cultures and agglutinated a variety of red blood cells. Tissue culture fluids from infected cell cultures also agglutinated red blood cells. Tumours were not transplantable by embedding the materials in a new set of animals, but appear to be transmissible via cannibalism.