Report of a Field Study on Mosquito (Diptera: Culicidae) Vectors of Dog Heartworm, Dirofilaria Immitis Leidy (Spirurida: Onchocercidae) Near Sydney, N.s.w., And the Implications for Veterinary and Public Health Concern.

Abstract

Transmission of dog heartworm has been increasing in many parts ofAustralia, but very little is known about the local mosquito vectors. For the first time in this country a range of natural vectors has been identified from a systematic field investigation in an area of known transmission. The study area centred on a dog pound which was surrounded by urban, semi-rural, and natural bushland conditions, supporting a diverse and abundant mosquito fauna. Mosquitoes were trapped for 3 months, over a summer, and scored for developing filariae. Of the eleven species collected seven were naturally infected, and four infective. Vector potential indices suggested that Culex annulirostris and Aedes notoscriprus were primary vectors, Anopheles annulipes and Cx. quinquefasciatus secondary vectors, and Ae. alboannulatus, Ae. rubrithorax, and Cx. australicus only minor vectors. The importance of the results in relation to control of the disease is discussed, although local factors will determine the relative significance of these or other vectors in different areas of Australia.