Isolation of Murray Valley encephalitis virus and other arboviruses in the Ord River Valley 1972-1976.

This paper summarizes the isolation of arboviruses from mosquitoes collected in the Ord Valley between 1972 and 1976. A total of one hundred and ninety five strains of at least fifteen antigenically distinct viruses have been isolated. Seven of these isolates appear to be "new' antigenic types, and several are undergoing further testing.

Ord River arboviruses--serological epidemiology.

This paper presents the results of haemagglutination-inhibition tests carried out on sera from 441 persons, 1,080 cattle and 335 birds in the Kimberley area. Two Alphaviruses (group A) (Ross River and Sindbis) and one Flavivirus (Murray Valley Encephalitis) were used for the preparation of haemagglutinins in the haemagglutination-inhibition tests. The tests showed a high percentage of antibody of Murray Valley Encephalitis in humans, birds and cattle, with an obvious focus of infection in the study site when cattle sera from different geographic areas were compared.

Ord River arboviruses--isolations from mosquitoes.

One hundred and thirty presumptive viruses have been isolated from 485 pools made from 23,872 mosquitoes collected in the Ord River area of North-West Australia. One hundred and eleven of the virus isolates isolates came from pools of Culex annulirostis, the dominant mosquito species caught in the vicinity of Kununurra. Forty-five of the viruses pathogenic for newborn mice have been further characterized-19 as Flaviviruses, 1 Alphavirus, 9 Koongol, 1 Mapputta and 15 non-haemagglutinating viruses of which 6 are Corripata.

Ord River arboviruses--the study site and mosquitoes.

The Ord Valey of tropical Western Australia has been studied for arbovirus activity following the development of a man-made lake of considerable size, a diversion dam and an irrigation scheme. Kununurra, the largest town in the valley, is the focus for very large populations of birds and mosquitoes. The irrigation areas have not been important as mosquito breeding areas because of the excessive use of insecticides.