Ross River virus in mosquitoes (Diptera:Culicidae) during the 1994 epidemic around Brisbane, Australia.

During the summer 1994 outbreak of epidemic polyarthritis in suburban Brisbane, 29,931 adult female mosquitoes were collected by octenol-CO2 light traps and tested for virus by species in pools of approximately 20 using an in situ enzyme-linked immunoassay. Overall, 63 isolations of Ross River (RR) virus were made from 7 different mosquito species, including 23 from freshwater-breeding Culex annulirostris Skuse, 13 from peridomestic Aedes notoscriptus (Skuse), 4 from Aedes procax (Skuse), 12 from the brackish water-breeding Aedes funereus (Theobald), 9 from saltmarsh Aedes vigilax (Skuse), and 1 each from Culex sitiens Wiedemann and Aedes alternans (Westwood). The RR virus minimum infection rate in mosquitoes ranged from 1.

Mortality of Culicoides brevitarsis fed on cattle treated with ivermectin.

Adult female Culicoides brevitarsis Kieffer, important vectors of arboviruses affecting livestock in Australia, were fed on penned Hereford yearling cattle which had been given a single subcutaneous injection of ivermectin at a dose of 200 mcg/kg. The mean mortality of engorged females 48 hr after feeding on the treated cattle was 99% for 10 days posttreatment and in excess of 40% for 18 days posttreatment. Based on these results, it appears that ivermectin administered subcutaneously could be a useful tool for the control of Culicoides-transmitted diseases and would provide an attractive alternative to "slaughter out" programs in the case of a major exotic disease threat.

Vectors of bluetongue virus in Australia.

Two of the 5 serotypes of bluetongue virus (BTV) known from Australia have been isolated from field collected insects. Serotype 20 was isolated in 1975 from a mixed pool of 214 insects containing several Culicoides species. Serotype 1 has been isolated from C.

Isolation of arboviruses from insects collected at Beatrice Hill, Northern Territory of Australia, 1974-1976.

Between October 1974 and May 1976, 57 596 mosquitoes, 169 957 Culicoides, 5923 Lasiohelea and 1043 phlebotomines were collected for virus isolation at Beatrice Hill (lat. 12 degrees 39'S.,long.

Peaton virus: a new Simbu group arbovirus isolated from cattle and Culicoides brevitarsis in Australia.

A new member of the Simbu group of arboviruses, for which the name Peaton virus is proposed, has been isolated from midges and cattle in Australia. Nine isolates were obtained from 101 pools of the biting midge Culicoides brevitarsis collected at Peachester, Qld, (26.51 degrees S.

Isolations of akabane virus from sentinel cattle and Culicoides brevitarsis.

A total of 14 isolations of Akabane virus were made from the blood of five cattle during sub-clinical infection. The serial isolation of this virus from four of these animals suggests a viraemia of at least 3 or 4 days. Neutralising antibody to Akabane virus in the serum of infected calves reached an initial peak titre of 32 to 256 four to five days after the viraemia but later uose further to a range of 64 to 512.

Onchocerca sweetae (Nematoda: Filarioidea): notes on the intermediate host.

Microfilariae of Onchocerca sweetae are broadly distributed in the superficial layers of the dermis of the water buffalo (Bubalus bubalis). A total of 2855 insects representing 20 species were collected from O. sweetae-infected bait buffaloes.

The isolation of Saumarez Reef virus, a new flavivirus, from bird ticks Ornithodoros capensis and Ixodes eudyptidis in Australia.

Strains of a new flavivirus, for which the name Saumarez Reef Virus is proposed, were isolated from seabird ticks collected from four localities. Two strains were isolated from ticks of the species Ornithodoros capensis Neumann 1901 collected from the nests of Sooty Terns, Sterna fuscata Linnaeus 1766 on coral cays off the east coast of Queensland, Australia. The other three strains were isolated from ticks of the species Ixodes eudyptidis Maskell 1885 taken from two dead Silver Gulls Larus novaehollandiae Stephens 1826 in northern Tasmania.

The epizootiology of bovine ephemeral fever in Australia and Papua-New Guinea.

The epizootiology of ephemeral fever in Australia from its first recognition until 1968 was reviewed. Since 1968, ephemeral fever often in a silent form has been shown to be enzootic in northern Australia, by the use of sentinel cattle. The major epizootics which occured in 1970-1971, 1972-1974 and 1974-1975 are described.

The infection of merino sheep with bovine ephemeral fever virus.

Four Merino sheep inoculated intravenously with bovine blood containing ephemeral fever virus showed no clinical signs of ephemeral fever. Two sheep showed a mild haematological response and developed a neutralising antibody which closely paralled that of a steer inoculated at the same time. Leucocytes harvested from these 2 sheep on days 3 and 4 after inoculation with virus reproduced ephemeral fever when inoculated into susceptible steers whilst those harvested on days 1, 2 and 5 did not.