Virus isolation and serological studies of arthropodborne virus infections in a high rainfall area of north queensland

Abstract

2 virus strains (1 identified as Wongal virus and 1, In1074, distinct from arboviruses previously isolated in Australia) were isolated from 29,395 mosquitoes of 61 species collected in 1963–1964 at 8 sites near Innisfail, in a high-rainfall area on the east coast of North Queensland. No virus strains were isolated from 157 birds of 54 species shot or netted in 1965. Serological tests also indicated infection with Sindbis virus in domestic fowls and with Edge Hill virus in rats and bandicoots. A high proportion of human sera collected in 1951–1955 as part of a study of febrile illness of unknown aetiology had antibody to Group A and Group B viruses, but few had changes in titre suggestive of current infection. 2 patients had serological evidence of infection with Ross River virus; both had mild illnesses, in 1 case with rash, but without arthralgia. 1 had fever and rash with serological evidence of infection with a Group B arbovirus following rat-bite. The results are considered not to support (but do not exclude) the possibility that the viruses of the Murray Valley encephalitis virus subgroup of Group B, active in northwest Queensland in the wet season but not yet detected there in the dry season, may survive throughout the year in rain forest near the east coast of North Queensland.