To estimate multipliers linking surveillance of salmonellosis, campylobacteriosis, and Shiga toxin-producing Escherichia coli (STEC) infections to community incidence, we used data from a gastroenteritis survey and other sources. Multipliers for severe (bloody stool/long duration) and milder cases were estimated from the component probabilities of doctor visit, stool test, sensitivity of laboratory test, and reporting to surveillance system. Pathogens were classifi ed by the same severity criteria and appropriate multipliers applied. Precision of estimates was quantifi ed by using simulation techniques to construct 95% credible intervals (CrIs). The multiplier for salmonellosis was estimated at 7 (95% CrI 4-16), for campylobacteriosis at 10 (95% CrI 7-22), and for STEC at 8 (95% CrI 3-75). Australian annual community incidence rates per 100,000 population were estimated as 262 (95% CrI 150-624), 1,184 (95% CrI 756-2,670), and 23 (95% CrI 13-54), respectively. Estimation of multipliers allows assessment of the true effects of these diseases and better understanding of public health surveillance.

The relative efficacy of a mechanical (Prokopack) collection method vs. manual aspiration in the collection of resting mosquitoes was evaluated in northern Tanzania before and after an intervention using indoor residual spraying and longlasting insecticide-treated nets. In smoke-free houses mosquitoes were collected from the roof and walls, but in smoky houses mosquitoes were found predominantly on the walls. Anopheles gambiae (Diptera: Culicidae) constituted 97.7% of the 312 An. gambiae complex specimens identified before but only 19.3% of the 183 identified after the intervention. A single sampling with the Prokopack collected a third of the available insects. Anopheles gambiae completed its gonotrophic development indoors, whereas Anopheles arabiensis did so outdoors. In both species gonotrophic development took 2 days. Most unfed resting An. arabiensis collected outdoors were virgins, whereas the majority of engorged insects were parous (with well-contracted sacs). Daily survival was estimated to be 80.0%. Only 9.4% of the engorged An. arabiensis collected outdoors and 47.1% of those collected indoors had fed on humans. Using the Prokopack sampler is more efficient than manual methods for the collection of resting mosquitoes. Malaria transmission may have been affected by a change in vector composition resulting from a change in feeding, rather than reduced survival. Monitoring the proportions of members of the An. gambiae complex may provide signals of an impending breakdown in control.

No abstract

Delay in the diagnosis of HIV infection is common in Victoria, but potentially avoidable in the majority of cases. Most people with delayed diagnosis had a history of male homosexual contact, injecting drug use, birth in a high-prevalence country or sexual contact with such individuals. An accurate sexual history, together with knowledge of their country of birth, should identify most individuals who should be offered an HIV test.

The incidence of HIV infection among men presenting to the VNPEPS is slightly lower than the HIV incidence in NPEP users in a recent Australian cohort study of men who have sex with men, but higher than HIV incidence in general gay male populations. Frequency of NPEP use was not associated with risk of HIV seroconversion. Examination of risk behaviour before and after NPEP use in this population is required to further assess the impact of NPEP availability and use on HIV incidence rates and risk behaviour in Australia.