Temporal trend and characteristics of recent HIV-1 infections: application of an algorithm for the identification of recently acquired HIV-1 infections among newly diagnosed individuals over a 10-year period.

Identification of recent infections (RI) may contribute to improve the quality of human immunodeficiency virus (HIV) surveillance, monitoring ongoing transmission and planning and evaluating prevention programs. Our study applied an algorithm combining clinical and serological information to identify RI in individuals newly diagnosed with HIV in Rome, during the years 1999-2008, in order to describe the trend and characteristics of recently infected individuals. RI were documented seroconverters, or people with an HIV avidity index (AI)<0.80. Individuals with advanced infection (CD4 count <200 cells/?L or AIDS-defining illness) or with AI ?0.80 were considered long-standing infections. Overall, we observed 2,563 new HIV diagnoses. The algorithm was applied in 2124/2563 (82.9%). Of these, 355 were RI (16.7%). RI was found independently associated with calendar year (adjusted odds ratio [aOR]= 1.06, 95% confidence intervals [CI]=[CI 1.02-1.11], for every year of increase), HIV-risk category (men having sex with men: aOR=1.44, [CI 1.04-1.98]; injecting drug users: aOR=1.58, [CI 1.03-2.42] vs. heterosexuals), country of origin (foreign-born: vs Italians: aOR=0.46, [CI 0.33-0.62]), and recruitment site (inpatient vs outpatient clinic: aOR=0.49, [CI 0.37-0.66]). By the application of our algorithm we could characterize the pattern of ongoing HIV transmission, identifying groups needing more urgent prevention programs.

HIV incidence estimate combining HIV/AIDS surveillance, testing history information and HIV test to identify recent infections in Lazio, Italy.

BACKGROUND: The application of serological methods in HIV/AIDS routine surveillance systems to identify persons with recently acquired HIV infection has been proposed as a tool which may provide an accurate description of the current transmission patterns of HIV. Using the information about recent infection it is possible to estimate HIV incidence, according to the model proposed by Karon et al. in 2008, that accounts for the effect of testing practices on the number of persons detected as recently infected. METHODS: We used data from HIV/AIDS surveillance in the period 2004-2008 to identify newly diagnosed persons. These were classified with recent/non-recent infection on the basis of an avidity index result, or laboratory evidence of recently acquired infection (i.e., previous documented negative HIV test within 6 months; or presence of HIV RNA or p24 antigen with simultaneous negative/indeterminate HIV antibody test). Multiple imputation was used to impute missing information. The incidence estimate was obtained as the number of persons detected as recently infected divided by the estimated probability of detection. Estimates were stratified by calendar year, transmission category, gender and nationality. RESULTS: During the period considered 3,633 new HIV diagnoses were reported to the regional surveillance system. Applying the model, we estimated that in 2004-2008 there were 5,465 new infections (95%CI: 4,538-6,461); stratifying by transmission category, the estimated number of infections was 2,599 among heterosexual contacts, 2,208 among men-who-have-sex-with-men, and 763 among injecting-drug-users. In 2008 there were 952 (625-1,229) new HIV infections (incidence of 19.9 per 100,000 person-years). In 2008, for men-who-have-sex-with-men (691 per 100,000 person-years) and injecting drug users (577 per 100,000 person-years) the incidence remained comparatively high with respect to the general population, although a decreasing pattern during 2004-2008 was observed for injecting-drug-users. CONCLUSIONS: These estimates suggest that the transmission of HIV infection in Lazio remains frequent and men-who-have-sex-with men and injecting-drug-users are still greatly affected although the majority of new infections occurs among heterosexual individuals.

Rapid detection and quantification of Chikungunya virus by a one-step reverse transcription polymerase chain reaction real-time assay.

Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus. A large outbreak of CHIKV disease occurred in 2005 in the Indian Ocean Islands. Many cases have been imported in European countries. Laboratory confirmation of suspected cases is mandatory for control measures during an outbreak. We report a novel, real-time, reverse transcription-polymerase chain reaction (RT-PCR) for the nonstructural protein 1 region that can quantify a wide range of viral RNA concentrations. This assay was validated by in vitro experiments in which interferon-alpha, a well-known virus inhibitor, showed a dose-dependent inhibition of virus replication on Vero cells that was assessed by viral infectivity and viral RNA production. This new real-time RT-PCR was used to measure viral load in serum samples from cases recently imported to Italy, and may be a useful tool in rapid detection of CHIKV and monitoring the extent of viral replication in patients.