Estimated cumulative incidence of West Nile virus infection in US adults, 1999-2010.

West Nile virus (WNV) was first recognized in the USA in 1999. We estimated the cumulative incidence of WNV infection in the USA from 1999 to 2010 using recently derived age- and sex-stratified ratios of infections to WNV neuroinvasive disease (WNND) and the number of WNND cases reported to national surveillance. We estimate that over 3 million persons have been infected with WNV in the USA, with the highest incidence rates in the central plains states. These 3 million infections would have resulted in about 780 000 illnesses. A substantial number of WNV infections and illnesses have occurred during the virus' first decade in the USA.

Predictors of mortality among women with AIDS in Illinois, USA.

Population-based surveillance data can help guide research priorities and plan programmes to prevent death among women with AIDS. We describe the predictors of mortality among women diagnosed with AIDS in Illinois, USA. Using the HIV/AIDS Reporting System), we identified 1944 adult women who were diagnosed with AIDS during January 1999-December 2004. The proportion of women who died within one year of diagnosis of AIDS declined from 97% in 1999 to 12% in 2005. Multivariate analysis indicated that age >or=45 years, intravenous drug use, diagnosis of clinical AIDS and hospitalization at the time of AIDS diagnosis were significant predictors of death among women with AIDS. The number of women who died soon after diagnosis with AIDS declined substantially. Nevertheless, prevention programmes designed to improve survival among women with AIDS should emphasize early diagnosis and referral for care in an effort to prevent first diagnosis with clinical AIDS during hospitalization.

Streptococcus agalactiae pulsed-field gel electrophoresis patterns cross capsular types.

Streptococcus agalactiae is a genetically diverse organism; when typed by pulsed-field gel electrophoresis (PFGE), multiple types appear within a single serotype. We tested whether S. agalactiae PFGE types correspond to a specific serotype within individuals, and different individuals from the same geographic area. A total of 872 S. agalactiae isolates from 152 healthy individuals were classified by PFGE and capsular serotype. Serotype V was the most homogeneous (Simpson's diversity index 0.54); and types III, II and Ib were mostly heterogeneous (Simpson's diversity index 0.90). Within an individual, isolates with the same PFGE patterns had identical capsular types, but across individuals the same PFGE types sometimes occurred in different serotypes. Capsular type alone is insufficient to define epidemiological relatedness. Although PFGE types appear to be a valid surrogate for capsular typing of isolates from the same individual, it is not a valid surrogate for serotype in isolates from different individuals.

Parental attitude towards mass antimicrobial prophylaxis during a school-associated pertussis outbreak.

We describe parental attitude towards mass antimicrobial prophylaxis and adolescent booster vaccination to prevent pertussis. A survey was distributed to parents at a large suburban high school where an outbreak of pertussis was occurring. A total of 314 surveys were received among 450 distributed. If antimicrobial prophylaxis was recommended for all students and faculty as a method of controlling a pertussis outbreak in their child's school (i.e. mass antimicrobial prophylaxis), 40% of parents would have their child take the medication and 49% might have their child take the antibiotic but would first consult their child's physician. Having > or =2 children attend the high school (OR 2.2, 95% CI 1.10-4.59) and generally favouring immunizations (OR 1.7, 95% CI 0.99-2.87) were predictors of likely compliance with mass antimicrobial prophylaxis. These findings underscore the importance of communicating the rationale of public health intervention efforts to physicians in order to help ensure their success.