Changes in the vaginal microbiota across a gradient of urbanization.

The vaginal microbiota of healthy women typically has low diversity, which increases after perturbations. Among these, lifestyle associated with certain sexual and antimicrobial practices may be associated with higher diversity. To test this hypothesis, we characterized the vaginal microbiota in the cervicovaginal and introital sites in sexually active Amerindians (N = 82) spanning urbanization, and in urban mestizos (N = 29), in the Venezuelan Amazonas. HPV status was also considered. Sampling was performed in an urban gradient from remote villages to a town, and women were individually classified by the degree of urbanization (low, medium, and high). Amerindian cervicovaginal and introital microbiota diversity were not associated with major changes in urbanization or ethnicity. There was a non-significant trend of increased diversity with urbanization, with a few taxa found overrepresented in urban Amerindians (Brevibacterium linens and Peptoniphilus lacrimalis) or mestizos (Mobiluncus mulieris and Prevotella sp.). Among all women, cervicovaginal and introital samples clustered, respectively, in four and two community state types (CSTs), where most profiles were dominated by Lactobacillus iners, Gardnerella vaginalis or were highly diverse profiles. HPV status did not associate with microbial diversity. In conclusion, no association was found between urban level and the vaginal microbiome in Amerindian women, and little difference was found between ethnicities. L. iners and high diversity profiles, associated with vaginal health outcomes, prevail in these populations.

High Rate of Infection by Only Oncogenic Human Papillomavirus in Amerindians.

Human papillomavirus (HPV), an etiological agent of cervical cancer (CC), has infected humans since ancient times. Amerindians are the furthest migrants out of Africa, and they reached the Americas more than 14,000 years ago. Some groups still remain isolated, and some migrate to towns, forming a gradient spanning urbanization. We hypothesized that, by virtue of their history, lifestyle, and isolation from the global society, remote Amerindian women have lower HPV diversity than do urban women (Amerindian or mestizo). Here we determined the diversity of the 25 most relevant cervical HPV types in 82 Amerindians spanning urbanization (low, medium, and high, consistent with the exposure to urban lifestyles of the town of Puerto Ayacucho in the Venezuelan Amazonas State), and in 29 urban mestizos from the town. Cervical, anal, oral, and introitus samples were taken, and HPVs were typed using reverse DNA hybridization. A total of 23 HPV types were detected, including 11 oncogenic or high-risk types, most associated with CC. Cervical HPV prevalence was 75%, with no differences by group, but Amerindians from low and medium urbanization level had significantly lower HPV diversity than mestizos did. In Amerindians, but not in mestizos, infections by only high-risk HPVs were higher than coinfections or by exclusively low-risk HPVs. Cervical abnormalities only were observed in Amerindians (9/82), consistent with their high HPV infection. The lower cervical HPV diversity in more isolated Amerindians is consistent with their lower exposure to the global pool, and transculturation to urban lifestyles could have implications on HPV ecology, infection, and virulence.IMPORTANCE The role of HPV type distribution on the disparity of cervical cancer (CC) incidence between human populations remains unknown. The incidence of CC in the Amazonas State of Venezuela is higher than the national average. In this study, we determined the diversity of known HPV types (the viral agent of CC) in Amerindian and mestizo women living in the Venezuelan Amazonas State. Understanding the ecological diversity of HPV in populations undergoing lifestyle transformations has important implication on public health measures for CC prevention.

Naturally acquired immune responses to malaria vaccine candidate antigens MSP3 and GLURP in Guahibo and Piaroa indigenous communities of the Venezuelan Amazon.

BACKGROUND: Malaria transmission in most of Latin America can be considered as controlled. In such a scenario, parameters of baseline immunity to malaria antigens are of specific interest with respect to future malaria eradication efforts. METHODS: A cross-sectional study was carried out in two indigenous population groups in Amazonas/Venezuela. Data from the regional malaria documentation system were extracted and participants from the ethnic groups of the Guahibo (n = 180) and Piaroa (n = 295) were investigated for the presence of Plasmodium parasites and naturally acquired antibodies to Plasmodium falciparum antigens in serum. The GMZ2 vaccine candidate proteins MSP3 and GLURP were chosen as serological markers. RESULTS: The incidence of P. falciparum in both communities was found to be less than 2%, and none of the participants harboured P. falciparum at the time of the cross-sectional. Nearly a quarter of the participants (111/475; 23,4%) had positive antibody titres to at least one of the antigens. 53/475 participants (11.2%) were positive for MSP3, and 93/475 participants (19.6%) were positive for GLURP. High positive responses were detected in 36/475 participants (7.6%) and 61/475 participants (12.8%) for MSP3 and GLURP, respectively. Guahibo participants had significantly higher antibody titres than Piaroa participants. CONCLUSIONS: Considering the low incidence of P. falciparum, submicroscopical infections may explain the comparatively high anti-P. falciparum antibody concentrations.