Mosquito (Diptera: Culicidae) and Arbo virus Activity on the South Coast of New South Wales, Australia, in 1985–1988

An investigation of the seasonal activity of adult mosquitoes and arboviruses in two native forests revealed a mosquito fauna comprising 33 species for the Mogo State Forest–Batemans Bay locality and 34 species for the Termeil State Forest. The mosquito Aedes vigilax was the most abundant species in salt marshes at Mogo State Forest–Batemans Bay, whereas the freshwater species Anopheles annulipes s.l. and Coquillettidia linealis were most abundant at Termeil State Forest. Major faunal differences between the two environments reflected the extensive saline marsh and mudflat estuarine habitats at Batemans Bay and the predominantly freshwater stream, marsh, and lake habitats of Termeil State Forest. A total of 218 virus isolates was recovered from the mosquitoes, comprising Ross River virus (86 isolates), Gan Gan virus (123 isolates), Termeil virus (2 isolates), and 7 unidentified viruses. The period of greatest arbovirus activity was from midsummer through midautumn and coincided with the overall peak activity of the most common mosquito species. Ae. vigilax yielded most isolates of Ross River and Gan Gan viruses and appeared to be the vector of greatest public health concern.