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Biomedical subjects

B H Kay

Publications and source records attributed to B H Kay.

119 records · Page 7Linked to original sources

Seasonal abundance of Culex annulirostris and other mosquitoes at Kowanyama, north Queensland, and Charleville, south west Queensland.

At Kowanyama, 104,006 adult female mosquitoes of a probable 47 species were collected on twelve occasions from April, 1972, to April, 1976. At Charleville, 71,791 adult females of 20 taxa were taken during thirteen periods from February, 1974, to February, 1976. Culex annulirostris was predominant at Kowanyama and especially at Charleville where it comprised up to 99% of dry season collections. Culex fatigans, Ae normanensis, An annulipes and, at Kowanyama only, An bancroftii were the other major species collected. Several bait trapping methods were suitable for monitoring densities of Cx annulirostris and other species but mammalian baits were best. Because Cx annulirostris activity continued throughout winter even at Charleville, continuous cycles of arbovirus transmission are possible, although the potential of dormant Aedes eggs also bears investigation as a method of arbovirus survival.

Animals↗

Isolation of virus strains from mosquitoes collected in Queensland, 1972-1976.

171,348 mosquitoes and 4,353 other arthropods collected at three centres in Queensland in 1972-1976 yielded 151 strains of 18 viruses. Culex annulirostris was the major source of virus isolation but 42 strains from Aedes normanensis indicate it to be a vector of importance. Ross River and Kokobera viruses were isolated at Kowanyama in the dry season, a finding of interest as being compatible with year-round survival in vector-vertebrate cycles. Culex fatigans has in part replaced Culex annulirostris in peridomestic breeding sites at Kowanyama; the infrequency of virus isolation from it suggests that this replacement may lower arbovirus infection rates. Twelve strains were identified as viruses antigenically distinct from any previously isolated in Australia or New Guinea: Ch16129, showed by the International Reference Centre for Arboviruses to be a previously undescribed member of the Simbu Group (Facey's Paddock virus), Ch16313 (Murweh), Ch19520 (Parker's Farm) and Ch19546 (little Sussex). The remaining strains were identified as viruses previously known in Australia, but included many new host or geographical records.

Aedes↗

Isolation of Sindbis (alphavirus) and Leanyer viruses from mosquitoes collected in the Northern Territory of Australia, 1974.

Mosquitoes collected near Darwin, Northern Territory, in 1974 yielded two virus strains. One was identified as Sindbis virus, not previously isolated from the Northern Territory. The other is antigenically distinct from viruses previously isolated from arthropods in Australia, and the name "Leanyer" is proposed for it. Its properties suggest that it may be a togavirus serologically unrelated to available alphaviruses and flaviviruses.

Animals↗

Murray Valley encephalitis virus infection in mosquitoes and domestic fowls in Queensland, 1974.

Field studies during an epidemic of Murray Valley encephalitis (MVE) led to the isolation of MVE virus from a pool of mosquitoes (Culex annulirostris) and a sentinel chicken from Charleville, south-west Queensland. A high proportion of domestic fowls at Charleville had antibody to MVE virus at the beginning of February 1974, in advance of the first case recognized in Queensland and allowing early warning from health authorities. A survey of antibody in domestic fowls in mid-1974 suggested widespread activity of MVE virus in western and east-central Queensland. Virus isolation and serological studies showed activity in south-west Queensland of three other viruses known to infect man, Ross River, Sindbis and Kunjin viruses.

Animals↗

Isolation of arboviruses (Kemerovo group, Sakhalin group) from Ixodes uriae collected at Macquarie Island, Southern ocean.

Eighty-nine pools of ticks (Ixodes [Ceratixodes] uriae White) collected at Macquarie Island (54 degrees 30' S, 159 degrees E) in the Southern Ocean yielded 16 strains of 2 viruses, 1 a "new" member of the Kemerovo group and 1 a "new" member of the Sakhalin group. The names "Nugget" and "Taggert" are proposed for them. Antigenically-related viruses have therefore now been isolated from I. uriae in both subarctic and subantarctic regions.

Animals↗

Assessment of the potential of dogs and cats as urban reservoirs of Ross River and Barmah Forest viruses.

OBJECTIVE: To determine whether dogs and cats are potential reservoirs of Ross River (RR) and Barmah Forest (BF) viruses METHOD: Young seronegative female dogs and cats were experimentally exposed to the viruses using Ochlerotatus vigilax (Skuse) mosquitoes. RESULTS: Only one of the 10 dogs and one of the 10 cats exposed to RR developed neutralising antibody. None of the animals developed detectable viraemia or clinical signs. One dog and three cats exposed to BF developed neutralising antibody. In addition, a serological survey of sera obtained from domestic dogs and cats residing in the Brisbane region indicated that 23.7% and 1.3% of dogs, and 14% and 2% of cats, had neutralising antibodies to RR and BF respectively. CONCLUSIONS: Although dogs and cats are exposed naturally to these viruses, and can become infected, they are unlikely to be important urban reservoirs of either virus.

Aedes↗