The impact of adulticide applications on mosquito density in Chicago, 2005.

The city of Chicago used ground ultra-low volume treatments of sumithrin (ANVIL 10+10) in areas with high West Nile virus infection rates among Culex mosquitoes. Two sequential treatments in Morbidity and Mortality Weekly Reports wk 31 and 32 decreased mean mosquito density by 54% from 2.5 to 1.1 mosquitoes per trap-day, whereas mosquito density increased by 153% from 1.3 to 3.3 mosquitoes per trap-day at the nonsprayed sites. The difference between these changes in mosquito density was statistically significant (confidence intervals for the difference in change: -4.7 to -1.9). Sequential adulticide treatments in September (wk 34 and 35) had no effect on mosquito density, probably because it was late in the season and the mosquitoes were presumably entering diapause and less active. Overall, there was significant decrease in mosquito density at the trap sites treated in all 4 wk (wk 31, 32, 34, and 35), suggesting that sustained sequential treatments suppressed mosquito density. Maximum likelihood estimates (MLE) of infection rate estimates varied independently of adulticide treatments, suggesting that the adulticide treatments had no direct effect on MLE. Mosquito trap counts were low, which was probably due to large numbers of alternative oviposition sites, especially catch basins competing with the gravid traps.

Evaluation and implementation of rapid HIV tests: the experience in 11 African countries.

Rapid HIV testing enables HIV prevention and care services to expand to settings with limited laboratory infrastructure. The World Health Organization recommends that prior to their implementation, rapid HIV tests first be evaluated at a reference laboratory and then at points-of-service, and that measures to ensure quality of testing be in place. We describe the experience of 11 African countries that implemented rapid HIV testing using this process. A questionnaire regarding rapid test evaluations and quality assurance measures was administered to personnel in ministries of health, reference laboratories, and Centers for Disease Control and Prevention programs in 11 African countries. In reference laboratory evaluations, median sensitivity was above 99% for 10 of 15 rapid tests and median specificity was above 99% for 13 of 15 rapid tests. Similar results were observed in evaluations at point-of-service sites. Rapid testing algorithms have been implemented in over 600 sites in nine of the countries. Concordance between point-of-service rapid testing and reference laboratory retesting of samples ranged from 95.7% to 99.5% (median: 98.7%). A systematic approach to the evaluation and implementation of rapid HIV tests was useful in ensuring accurate, decentralized testing even when conducted by persons with limited laboratory experience.

Water sources are associated with childhood diarrhoea prevalence in rural east-central Mali.

BACKGROUND: Water supply improvements generally reduce the incidence of diarrhoea. However, populations with limited access to a safe water supply may continue to draw water from unimproved sources, thereby increasing their risk of diarrhoea. Furthermore, young children who are not breastfed may be even more susceptible to water-borne diarrhoeal pathogens. Our study explored the interactive protective effects against diarrhoea of exclusively using improved water sources and breastfeeding among children in rural Mali. METHODS: Interviews were conducted with parents or guardians of children under 7 years of age in seven villages with access to a variety of water supplies. Water sources used, breastfeeding status, demographics and recent diarrhoea symptoms were determined for 1117 children. The cross-sectional findings were used to compare diarrhoea prevalence among exclusive and non-exclusive users of improved water sources. Variation in prevalence by age and exclusive breastfeeding status was evaluated using chi-square and multivariate analyses. RESULTS: Children whose water was drawn exclusively from wells had a significantly lower prevalence of diarrhoea as compared with children whose water was drawn from a spring or stream (5.9% vs. 8.7%; P=0.04). The exclusive use of improved water sources had no impact on diarrhoea prevalence among children who were exclusively breastfed. Similarly, the strongest protective effect was observed among children who were not exclusively breastfed. CONCLUSIONS: Our results indicate that using surface water as a primary or secondary water source exposes children to greater risk of diarrhoeal disease than using only improved sources such as wells. It is particularly beneficial for young children who are not exclusively breastfed to be supplied with water drawn from improved sources.

Acute occupational pesticide-related illness in the US, 1998-1999: surveillance findings from the SENSOR-pesticides program.

BACKGROUND: Concern about the adverse public health and environmental effects of pesticide use is persistent. Recognizing the importance of surveillance for acute occupational pesticide-related illness, we report on surveillance for this condition across multiple states. METHODS: Survey data collected between 1998 and 1999 were obtained from the seven states that conduct acute occupational pesticide-related illness surveillance as part of the Sentinel Event Notification System for Occupational Risks (SENSOR) program. Data were collected by these state programs in a standardized manner and analyzed. Acute occupational pesticide-related illness incidence rates for those employed in agriculture and those employed in non-agricultural industries were also calculated. RESULTS: Between 1998 and 1999, a total of 1,009 individuals with acute occupational pesticide-related illness were identified by states participating in the SENSOR-pesticides program. The mean age was 36 years, and incidence rates peaked among 20-24 year-old workers. The overall incidence rate was 1.17 per 100,000 full time equivalents (FTEs). The incidence rate among those employed in agriculture was higher (18.2/100,000 FTEs) compared to those employed in non-agricultural industries (0.53/100,000 FTEs). Most of the illnesses were of low severity (69.7%). Severity was moderate in 29.6% of the cases, and high in four cases (0.4%). Three fatalities were identified. Insecticides were responsible for 49% of all illnesses. CONCLUSIONS: Surveillance is an important tool to assess acute pesticide-related illness, and to identify associated risk factors. Our findings suggest that these illnesses continue to be an important occupational health problem, especially in agriculture. As such, greater efforts are needed to prevent acute occupational pesticide-related illness.