Ord River Arboviruses — Serological Epidemiology

Abstract

Summary. This paper presents the results of haeniagglutination-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 haeniagglutination-inhibition tests. The tests showed a high percentage of antibody to 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. These results are discussed in relation to the evolution and ecology of arboviruses in the Ord River area.INTRODUCTION.

Genetic Variation of Murray Valley Encephalitis Virus

“…Serological studies of man and animals in the north of Australia (Liehne et al, 1976a;Doherty et al, 1977) have shown a high prevalence of MVE antibodies. The principal vertebrate hosts are believed to be water-birds (Liehne et al, 1976a;Marshall et al, 1982).…”

“…The principal vertebrate hosts are believed to be water-birds (Liehne et al, 1976a;Marshall et al, 1982). Culex annulirostris appears to be the major vector in the primary cycle (Kay, 1980Wright et al, 1981).…”

Isolation of Murray Valley Encephalitis Virus and Other Arboviruses in the Ord River Valley 1972–1976

“…MVE had also been isolated from mosquitoes in Western Australia in 1972, 1973and 1974(Liehne et al, 1976a. Furthermore, serological data from the Ord Valley indicate widespread involvement of domestic mammals and domestic and wild birds in the transmission of this virus (Liehne et al, 1976b). This publication reviews and analyses all arbovirus isolations from mosquitoes collected in the Ord Valley between 1972 and 1976.…”

Influence of Hosts on the Ecology of Arboviral Transmission: Potential Mechanisms Influencing Dengue, Murray Valley Encephalitis, and Ross River Virus in Australia

“…Antibodies to MVEV have been detected in many vertebrate species, including ciconiiforms (herons and egrets), pelecaniforms, placental and marsupial mammals (Anderson et al 1952, Boyle et al 1983b, Fraser et al 1986, Gard et al 1976, Kay et al 1987a, Liehne et al 1976, Marshall et al 1982a. Ciconiiforms appear to be the reservoirs of MVEV, owing to high antibody prevalence, association with human clinical cases, infection studies, relatively rapid reproductive rates, and consequent generation of susceptible hosts (Anderson et al 1952, Boyle et al 1983a, 1983b, Broom et al 2002, 2003, Marshall 1988, Russell 1995.…”

“…However, the role of host abundance on the transmission of MVEV is not well understood. It is likely that colonial nesting of avian hosts contributes to MVEV transmission (Anderson 1953, Liehne et al 1976, Scherer et al 1959, Whitehead et al 1968. For example, a surge in ciconiiform breeding in the Murray Valley basin occurred just prior to an epidemic of MVE in 1974-1975(Braithwaite and Clayton 1976, Marshall 1988.…”