Japanese encephalitis on Badu Island, Australia: the first isolation of Japanese encephalitis virus from Culex gelidus in the Australasian region and the role of mosquito host-feeding patterns in virus transmission cycles

During investigation of an outbreak of Japanese encephalitis (JE) in the Torres Strait, Australia, in 2000, mosquitoes were collected in Badu Island community and at a newly established communal piggery about 3 km from the community. A total of 94285 mosquitoes, comprising 91240 (96.8%) unengorged females, 1630 (1.7%) blood-engorged females and 1415 (1.5%) males, were processed for virus isolation. One isolate of JE virus was obtained from Culex gelidus, with a minimum infection rate of 12.4:1000. This is the first isolate of JE virus from Cx. gelidus in the Australasian region. No isolates were obtained from Cx. annulirostris, the primary implicated Australian JE vector. Analysis of mosquito host-feeding patterns, using gel diffusion, demonstrated that Cx. annulirostris and 5 other species fed predominately on mammals, Analysis of blood-fed mosquitoes collected within the community demonstrated that the proportion of Cx. annulirostris feeding on pigs in 2000 (2.3%) was significantly lower than that for the 1995-97 period (31.3%). The removal of the pigs from Badu Island community has limited the contact between potential amplifying hosts and mosquitoes, thus potentially reducing the risk of transmission of JE virus to the human population.

The appearance of a second genotype of Japanese encephalitis virus in the Australasian region

In mid-January 2000, the reappearance of Japanese encephalitis (JE) virus activity in the Australasian region was first demonstrated by the isolation of JE virus from 3 sentinel pigs on Badu Island in the Torres Strait. Further evidence of JE virus activity was revealed through the isolation of JE virus from Cidex gelidus mosquitoes collected on Badu Island and the detection of specific JE virus neutralizing antibodies in 3 pigs from Saint Pauls community on Moa Island. Nucleotide sequencing and phylogenetic analyses of the premembrane and envelope genes were performed which showed that both the pig and mosquito JE virus isolates (TSOO and TS4152, respectively) clustered in genotype I, along with northern Thai, Cambodian, and Korean isolates. All previous Australasian JE virus isolates belong to genotype II, along with Malaysian and Indonesian isolates. Therefore, for the first time, the appearance and transmission of a second genotype of JE virus in the Australasian region has been demonstrated.

Mental health telemedicine programmes in Australia

A national survey of mental health telemedicine programmes was conducted and data collected on their catchment areas, organizational structure, equipment, clinical and non-clinical activity, and use by populations who traditionally have been poorly served by mental health services in Australia. Of 25 programmes surveyed, information was obtained for 23. Sixteen programmes had dealt with a total of 526 clients during the preceding three months. Of these, 397 (75%) were resident in rural or remote locations at the time of consultation. Thirty-seven (7%) were Aboriginals or Torres Strait Islanders. Only 19 (4%) were migrants from non-English-speaking backgrounds. The programmes provided both direct clinical and secondary support services. Overall, the number of videoconferencing sessions devoted to clinical activity was low, the average being 123 sessions of direct clinical care per programme per year. Videoconferencing was also used for professional education, peer support., professional supervision, administration and linking families. The results of the study suggest that telehealth can increase access to mental health services for people in rural and remote areas, particularly those who have hitherto been poorly served by mental health services in Australia.

High prevalence of asthma in five remote indigenous communities in Australia

Data on the prevalence of asthma in children residing in remote indigenous communities in Australia are sparse, despite the many reports of high prevalence in nonindigenous children of this country. Two previous Australian studies have had poor participation rates, limiting interpretation of their results. A study of children in the Torres Strait and Northern Peninsula Area of Australia was conducted to document the prevalence of asthma symptoms. Five indigenous communities were randomly selected and trained interviewers, who were local indigenous health workers, recruited participants using a house-by-house approach. Information was collected by a structured face-to-face interview based on standardized questionnaire constructed from the protocol International Study of Asthma and Allergy in Childhood; 1,650 children were included in the study with a 98% response rate. Overall, the prevalence of self-reported ever wheezing was 21%,; 12% reported wheezing in the previous year; and 16%, reported ever having asthma, There was significant variation in the prevalence of asthma symptoms between communities. It is concluded that there are significant intercommunity variations in the prevalence of asthma symptoms in remote communities and that the prevalence in these communities is as high as in nonindigenous groups.

Editorial

This issue is devoted to two special Focus sections: one on the radicalism and relevance still of Eleanor Dark's novels written in the early to mid- twentieth century, one on the perspectives and practices of 1990s and current third wave feminism.

Community attitudes to researchers

A non-Indigenous researcher who previously worked as a remote community nurse provides insights into how non-Indigenous researchers are viewed by non-Indigenous practitioners in those settings because in Australian Aboriginal communities most community health nurses had a cynical view of visiting researchers. These attitudes illustrate the need for the establishment of mutually fulfilling relationships with those among whom they work.

Stream-bank shade and larval distribution of the Philippine malaria vector Anopheles flavirostris

The principal malaria vector in the Philippines, Anopheles flavirostris (Ludlow) (Diptera: Culicidae), is regarded as 'shade-loving' for its breeding sites, i.e. larval habitats. This long-standing belief, based on circumstantial observations rather than ecological analysis, has guided larval control methods such as 'stream-clearing' or the removal of riparian vegetation, to reduce the local abundance of An. flavirostris . We measured the distribution and abundance of An. flavirostris larvae in relation to canopy vegetation cover along a stream in Quezon Province, the Philippines. Estimates of canopy openness and light measurements were obtained by an approximation method that used simplified assumptions about the sun, and by hemispherical photographs analysed using the program hemiphot(C) . The location of larvae, shade and other landscape features was incorporated into a geographical information system (GIS) analysis. Early larval instars of An. flavirostris were found to be clustered and more often present in shadier sites, whereas abundance was higher in sunnier sites. For later instars, distribution was more evenly dispersed and only weakly related to shade. The best predictor of late-instar larvae was the density of early instars. Distribution and abundance of larvae were related over time (24 days). This pattern indicates favoured areas for oviposition and adult emergence, and may be predictable. Canopy measurements by the approximation method correlated better with larval abundance than hemispherical photography, being economical and practical for field use. Whereas shade or shade-related factors apparently have effects on larval distribution of An. flavirostris , they do not explain it completely. Until more is known about the bionomics of this vector and the efficacy and environmental effects of stream-clearing, we recommend caution in the use of this larval control method.