Infection and Multiplication of Ross River Virus in the Mosquito Vector Aedes-Vigilax (Skuse)

Abstract

Aedes vigilax mosquitoes, collected from the south coast of New South Wales, were fed on a blood-meal containing the T48 strain of Ross River virus. Viral infection and multiplication in this major vector were studied, together with dissemination of the virus in organs and tissues as determined by immunofluorescence. Individuals of this field mosquito population were highly susceptible to infection (ID50 = 10(3.4) BHK-21 TCID50 per mosquito) and virus replicated rapidly, reaching a maximum level 5-6 days after feeding. Specific viral antigens were detected in sections of abdominal midgut, abdominal fat bodies, thoracic fat bodies, cerebral ganglia and head fat bodies 2-4 days after ingestion of the virus-containing bloodmeal. Antigens were also detected 5-7 days after feeding in abdominal ganglia, thoracic ganglia, salivary glands and foregut. Antigens were demonstrated in sections of eggs from the ovary of one mosquito, which provided further evidence of transovarial transmission of Ross River virus in Ae. vigilax.