Organ distribution of infectivity and complement-fixing antigen with two Nigerian arboviruses.

Time course studies intended to throw some light on the pathogenesis of some recently isolated Nigerian arboviruses were conducted by following the production of infective virus and complement-fixing (CF) antigen and correlating these with pathological changes in the brain and in the liver of suckling white Swiss mice. Two prototypes of the Nigerian arboviruses were employed: IB.AR.1792 (Dugbe) a hitherto undescribed arbovirus, isolated from and IB.AR.2012 (Thogoto) isolated from Following infection with virus 1792, titres of both infective virus and CF antigen increased rapidly in the brain. Infective virus was also produced in the liver but CF antigen was virtually negative. With virus 2012 infection, infective virus and CF antigen titres rose rapidly in the liver. But in the brain although infective virus was produced to a high titre, CF antigen was not demonstrated. Histopathological examination showed a positive correlation between the presence of CF antigen (and not infective virus ) and pathologic changes. There was encephalitis and cell degeneration in brain infected with virus 1792. The striking pathological changes in liver infected with virus 2012 were proliferation of the bile ducts, congested vessels and dilation of the sinusoids.