Seroprevalence of and risk factors for HIV-1 infection among female commercial sex workers in South America

OBJECTIVE

Assessment of HIV prevalence and associated risk behaviours among female commercial sex workers (FCSW) across major cities in South America.

METHODS

Seroepidemiological, cross sectional studies of 13 600 FCSW were conducted in nine countries of South America during the years 1999-2002. Participants were recruited in brothels, massage parlours, hotels, and streets where anonymous questionnaires and blood samples were collected. HIV infection was determined by enzyme linked immunosorbent assay (ELISA) screening and western blot confirmatory tests.

RESULTS

The overall HIV seroprevalence was 1.2% (range 0.0%-4.5%). The highest HIV seroprevalences were reported in Argentina (4.5%) and Paraguay (2.6%); no HIV infected FCSW were detected in Venezuela and Chile. Consistent predictors of HIV seropositivity were: (1) a previous history of sexually transmitted infections (STI, AORs = 3.8-8.3), and (2) 10 years or more in commercial sex work (AORs = 2.2-24.8). In addition, multiple (> or =3) sexual contacts (AOR = 5.0), sex with foreigners (AOR = 6.9), use of illegal drugs (AOR = 3.2), and marijuana use (AOR = 8.2) were associated with HIV seropositivity in Southern Cone countries.

CONCLUSIONS

Consistently low HIV seroprevalences were detected among FCSW in South America, particularly in the Andean region. Predictors of HIV infection across the continent were STI and length of commercial sex work; however, use of illegal drugs, especially marijuana, and sexual contacts with foreigners were also found to be associated risk factors in the Southern Cone region. Interventions for the control of HIV and other STI need to be region and country specific; drug use appears to have an ever increasing role in the spread of HIV among heterosexually active populations.

Thyroperoxidase immunodetection for the diagnosis of malignancy on fine-needle aspiration of thyroid nodules

We have previously demonstrated that in 95.6% of malignant thyroid tumors the enzyme thyroid peroxidase (TPO) presents antigenic changes detectable by a monoclonal antibody termed MoAb47. The aim of this study was to investigate the interest of TPO immunodetection for the diagnosis of malignancy on fine-needle aspiration biopsy (FNAB) of thyroid nodules. The study was performed on 300 patients. Slides of FNAB aspirate were air-dried and stained by anti-TPO-MoAb47. According to the percentage of TPO-positive epithelial cells, patients were divided into two groups: benign (> 80%) and malignant (< 80%). In 279 cases additional slides were available for Giemsa stain and standard cytology. All the patients were operated on, and the final diagnosis was recorded as benign in 248 cases (183 macrofollicular nodules, 23 microfollicular adenomas, 18 atypical adenomas, 11 oncocytomas, 11 thyroiditis, 2 Graves' disease) and malignant in 52 cases (44 papillary carcinomas and 8 follicular carcinomas). Samples from 215 of 248 benign nodules yielded 80% to 100% TPO-positive cells, whereas samples from all malignant tumors yielded less than 80% positive cells. The sensitivity of TPO staining for diagnosis of malignancy was thus 100%, its specificity 86.7%, and its overall accuracy 89%. With conventional cytology, sensitivity, specificity, and accuracy were 91.6%, 79.2%, and 81.0%, respectively. We conclude from this study that TPO staining with MoAb47 should become an essential adjunct in the preoperative cytologic diagnosis of thyroid nodules.