HIV and syphilis in the context of community vulnerability among indigenous people in the Brazilian Amazon.

BACKGROUND: Contextual factors shape the risk of acquiring human immunodeficiency virus (HIV) and syphilis. We estimated the prevalence of both infections among indigenous people in nine indigenous health districts of the Brazilian Amazon and examined the context of community vulnerability to acquiring these infections. METHODS: We trained 509 health care workers to screen sexually active populations in the community for syphilis and HIV using rapid testing (RT). We then assessed the prevalence of HIV and syphilis using RT. A multivariable analysis was used to identify factors associated with syphilis infection (sociodemographic, condom use, intrusion, population mobility, and violence). RESULTS: Of the 45,967 indigenous people tested, the mean age was 22.5 years (standard deviation: 9.2), and 56.5% were female. Overall, for HIV, the prevalence was 0.13% (57/43,221), and for syphilis, the prevalence was 1.82% (745/40,934). The prevalence in men, women, and pregnant women for HIV was 0.16%, 0.11%, and 0.07%, respectively, and for syphilis, it was 2.23%, 1.51%, and 1.52%, respectively. The district Vale do Javari had the highest prevalence of both infections (HIV: 3.38%, syphilis: 1.39%). This district also had the highest population mobility and intrusion and the lowest availability of prenatal services. Syphilis infection was independently associated with age (odds ratio [OR] 1.04, 95% confidence interval [CI]: 1.03-1.05), male sex (OR 1.32, 95% CI: 1.14-1.52), and mobility (moderate: OR: 7.46, 95% CI: 2.69-20.67; high: OR 7.09, 95% CI: 3.79-13.26). CONCLUSIONS: The large-scale integration of RT in remote areas increased case detection among pregnant women, especially for syphilis, in districts with higher vulnerability. Mobility is an important risk factor, especially in districts with higher vulnerability. Contextually appropriate approaches that address this factor could contribute to the long-term success of HIV and syphilis control programs

Evaluation of screening for Chlamydia trachomatis among young women in primary health care services in Manaus, Amazonas State, Brazil

Abstract: Screening for Chlamydia trachomatis is not routinely offered to young asymptomatic women in Brazil. This study evaluated the performance, usefulness, and operational suitability of the Digene Hybrid Capture II (HCII) CT-ID DNA-test as an opportunistic screening tool to detect C. trachomatis in the public health system in Manaus, Amazonas State. Women aged 14-25 years who attended primary health care services were interviewed and one cervical specimen was collected during cytological screening. The HCII CT test was evaluated for its ability to detect the presence of C. trachomatis and against real-time PCR (q-PCR) in a subset of samples. Operational performance was assessed through interviews with providers and patients. Overall, 1,187 women were screened, and 1,169 had a HCII CT-ID test result (292 of these were also tested by q-PCR). Of those, 13.1% (n = 153) were positive. The sensitivity, specificity, positive and negative predictive values of HCII CT were 72.3% (95%CI: 65.4-78.6), 91.3% (95%CI: 84.1-95.9), 93.8% (95%CI: 88.5-97.1), and 64.4% (95%CI: 56.0-72.1), respectively. Sample collection caused discomfort in 19.7% of women. Among health professionals (n = 52), the main barriers reported included positive cases who did not return for results (56.4%), unwillingness to screen without an appointment (45.1%), and increase in their workload (38.8%). HCII CT-ID identified a high proportion of C. trachomatis cases among young women in Manaus. However, its moderate sensitivity limits its use as an opportunistic screening tool in primary health care settings in Manaus. Screening was well accepted although the barriers we identified, especially among health professionals, challenge screening detection and treatment efforts

External quality assurance with dried tube specimens (DTS) for point-of-care syphilis and HIV tests: experience in an indigenous populations screening programme in the Brazilian Amazon.

OBJECTIVES: The availability of point-of-care (POC) tests for infectious diseases has revolutionised the provision of healthcare for remote rural populations without access to laboratories. However, quality assurance for POC tests has been largely overlooked. We have evaluated the use and stability of dry tube specimens (DTS) for External Quality Assurance (EQA) for HIV and syphilis screening in remote indigenous populations in the Amazon region of Brazil. METHODS: All healthcare workers (HCWs) participating in the community-screening were trained. We used HIV and syphilis DTS panels developed by the reference laboratory, containing samples with negative and positive results at different antibody concentrations, for both infections. DTS panels were distributed to HCWs in the communities for reconstitution and testing using POC HIV and syphilis tests. The results of testing were sent to the reference laboratory for marking and remedial action taken where necessary. RESULTS: In total 268 HCWs tested 1607 samples for syphilis and 1608 samples for HIV. Results from HCWs showed a concordance rate of 90% for syphilis and 93% for HIV (κ coefficients of 0.74 and 0.78, respectively) with reference laboratories. Most false negatives were in samples of very low antibody concentration. DTS syphilis specimens produced the expected results after storage at 2-8°C or at 18-24°C for up to 3 weeks. CONCLUSIONS: The results show that POC tests for syphilis and HIV give valid results in environments where traditional tests do not work, but errors in the interpretation of POC test results were identified by the EQA programme using DTS. EQA using DTS can help to improve the quality of screening programmes using POC tests in remote regions