Miguel Angel Sánchez-Alemán

HPV infection, risk factors and viral load among Mexican male college students

OBJECTIVES To determine the prevalence of HPV and the risky sexual behaviors associated to it in a sample of male college students, taking into account genotype and viral load. METHODS From 2002 to 2003, male students from the Autonomous University of Morelos State completed a questionnaire and provided self-collected genital samples to detect and quantify HPV. We performed a bivariate and a multivariate logistic regression analysis to identify correlates associated with the infection and to assess the viral load as a function of the viral infecting type. The fragments of β-globin gene and L1 of HPV, were amplified, purified and cloned, to evaluate viral load. RESULTS Among 253 subjects, HPV prevalence was 19.4%, and HPV16 was the most common subtype. History of STIs (OR=4.8; 95% CI 1.2-18.9), contraceptive pill use by female partner (OR=2.6; 95% CI 1.1-6.3) and exchanging sex for money (OR=4.9; 95% CI 1.2-20) were associated to the HPV infection. HPV16 viral load was 7.8 copies (HPV/beta-globin) compared to 0.9 copies for other HPV types. DISCUSSION HPV16 displayed the highest viral load, and it was the most prevalent. It was found that using contraceptive pills by female partners was associated with HPV infection.

Avidity of Antibodies against HSV-2 and Risk to Neonatal Transmission among Mexican Pregnant Women

Objective. To determine HSV-2 seroprevalence, risk factors, and antibody avidity among a sample of Mexican pregnant women. Material and Methods. The avidity test was standardized with different urea concentrations and incubation times; the cut-off point was calculated to determine the low avidity (early infection). IgG antibodies against HSV-2 were detected from pregnant and postpartum women from Morelos, Mexico, and the avidity test was performed to positive samples. Multivariate regression logistic analysis was employed to evaluate demographic and sexual behavior characteristics associated with HSV-2 infection. Results. HSV-2 seroprevalence among Mexican women analyzed was 14.5% (333/2300), demographic factors (location of General Hospital, age, education level, and civil status), and risky sexual behaviors (STI self-report and number of sexual partners during last year) were associated with HSV-2 infection. Seventeen women were detected with low avidity antibodies (early infection) with a cut-off point of 66.1%. Conclusions. HSV-2 infection was common among this group of women from Mexico; the avidity test detected women with recent infections, and these women were more likely to transmit HSV-2 to their neonates. Neonatal herpes has no epidemiological surveillance, the disease could be overlooked, and so more studies are needed to estimate the magnitude of neonatal infection.

Maternal/Child Seroprevalence of Antibodies Against Treponema pallidum at Four General Hospitals in the State of Morelos, Mexico

BACKGROUND AND AIMS Treponema pallidum can cause syphilis in pregnant women and congenital syphilis in the newborn. In Latin America, 330,000 pregnant women are diagnosed with syphilis every year. Adequate prenatal care to detect syphilis reduces maternal morbidity and fetal and neonatal mortality and morbidity. We undertook this study to determine T. pallidum seroprevalence among pregnant and puerperal women from Morelos, Mexico, as well as to evaluate the sexual behavior, demographic and clinical variables associated with the infection. METHODS A cross-sectional study was carried out among pregnant and puerperal women from four general hospitals from Morelos, Mexico during 2005-2009. Women answered a questionnaire and provided a blood sample to detect antibodies against T. pallidum. RESULTS A total of 2331 women were analyzed with 0.26% of T. pallidum seroprevalence. There were four cases with active syphilis and two cases with latent syphilis, as well as two cases of congenital syphilis. Illiterate women had 6.7 times higher risk of being infected. Women who did not undergo a urine test had a 5.3 times higher risk for infection and women who do not have piped water inside their household had a 5.0-fold higher risk of having anti-T. pallidum antibodies. All seropositive cases were from the same hospital (Cuautla General Hospital) with demographic, sexual behavior and medical care characteristics different from the other three hospitals. CONCLUSIONS Syphilis during pregnancy and congenital syphilis are still present in Mexico. It may be that the more urban a population the higher the chance of the prevalence of maternal syphilis. It would be beneficial to reinforce the observance of the Official Mexican Norm and to implement rapid diagnostics tests to contend with this public health problem.

Heterogeneity of Herpes Simplex Virus Type 2 Seroprevalence From a National Probability Survey In Mexico, 2012

BackgroundHerpes simplex virus type 2 (HSV-2) seroprevalence and associated infection risk factors show differences by regions and countries. The aims of the study were to determine the HSV-2 seroprevalence and to evaluate the risk factors for HSV-2 in a national representative survey among adolescents and adults in Mexico. MethodsA cross-sectional study was carried out in Mexico on the basis of the National Health and Nutrition Survey 2012, a national representative survey. Demographic, sexual behavior, reproductive health, and lifestyles indicators were considered in the current study. Participants provided biological samples—dried blood spots—to test for HSV-2 antibodies using enzyme-linked immunosorbent assay and Western blot. Bivariate and multivariate analyses were performed to identify variables associated with HSV-2 infections analyzed by sex. ResultsNational HSV-2 seroprevalence was 9.9%, 2.4% among adolescents and 11.7% among adults with HSV-2 seroprevalence heterogeneous across the country. Women had 12.2% of antibodies against HSV-2 and men had 7.5%. The factors associated with HSV-2 infection among women were age (45–49 years; odds ratio [OR], 19.8), region (southwest; OR, 3.0), urbanization (urban; OR, 1.9), age at sexual debut (⩽14 years; OR, 3.4), education level (any; OR, 3.0), and previous abortion (≥2 abortion; OR, 2.1). Among men, age (45–49 years; OR, 11.7), region (southwest; OR, 3.0), urbanization (urban, odds ratio [OR], 1.7), and HIV care (OR, 7.1) were associated with the infection. ConclusionsApproximately 10% of Mexicans aged 15 to 49 years had HSV-2 antibodies, with differences by sex, region, education level, urbanization, HIV care, and childbirth, highlighting the relevance of health inequalities in the country: social inequalities seem to matter in terms of the probability of HSV-2 infections.

Marcadores serológicos de hepatitis B y C, y VIH en La Calera y Cuambio, Guerrero, México

OBJECTIVE: To perform a hepatitis B, C, and HIV survey in an enhanced sample from two rural communities with the highest anti-HBc prevalence found in ENSA 2000. MATERIALS AND METHODS: This was a cross-sectional study.We studied the communities of La Calera and Cuambio, two adjacent rural towns of the district of Zirandaro, Guerrero, targeted because of the high prevalence of anti-HBc shown in ENSA 2000.We assessed the prevalence of hepatitis B and C, and HIV serological markers and associated factors among inhabitants older than 10 years. RESULTS: A very high prevalence of hepatitis B markers associated with socioeconomic factors was confirmed, while hepatitis C prevalence was low and HIV absent in the two communities addressed. CONCLUSIONS: National serosurveys are an accurate tool for identifying communities with hepatitis B high endemicity where focused research and control measures are needed.

Hepatitis A seroprevalence in adolescents and young adults in Mexico: A 2012 National Health and Nutrition Survey analysis

To describe hepatitis A virus (HAV) seroprevalence and associated factors in adolescents (10-19 years) and young adults (20-25 years) in different Mexican regions, using 2012 National Health and Nutrition Survey data. A random selection of 1581 serum samples was analyzed. Weighted HAV seroprevalence with 95% confidence intervals (95%CI) and its association with sociodemographic factors were estimated. Mean weighted HAV seroprevalence was 69.3% (95%CI: 64.8-73.4) overall, with 58.8% (95%CI: 53.4-64.1) in adolescents and 83.0% (95%CI: 75.3-88.7) in young adults. By age of 10, 46.7% (95%CI: 33.9-60.0) were seropositive and by age of 15, 52.8% (95%CI: 36.5-68.5), corresponding to intermediate endemicity nationally. Factors associated with HAV seropositivity (adjusted odds ratio, aOR) included: lower socioeconomic status (SES) (aOR = 4.09 for low and aOR = 2.31 for medium versus high SES), older age (aOR = 0.29 for adolescents versus young adults), living in the South (aOR = 2.12 versus Central Mexico) or in rural areas (aOR = 2.25 versus urban areas). Regional differences and increased seroprevalence of HAV in marginalized populations present an important public health issue, as a relatively large proportion of young adults are susceptible to infection. The burden of symptomatic disease must be addressed further to support specific programs of continued sanitation and education improvement, and the possibility of vaccination in more susceptible regions.

Real time PCR to evaluate HSV-2 shedding from anal and genital samples among men who have sex with men, living with HIV

This study shows the relative quantification of HSV‐2 by qPCR, using the MIQE Guidelines. The reaction efficiency was evaluated, and the relative quantification used the R = 2−ΔCq method. The relative quantification of HSV‐2 was conducted with anal and genital samples from men who have sex with men (MSM), living with HIV. The presence of a single amplification product was validated with a dissociation curves profile and the determination of the melting temperature. The limit of detection for β‐globin was determined as 3.3 × 10−5 ng/μL, and for HSV‐2 at 6.0 × 10−6 ng/μL. The efficiency for β‐globin was 100.2% and for HSV‐2 was 106.8%. From 336 MSM, 2.1% and 3.9% individuals presented anal or genital HSV‐2 shedding, respectively. The HSV‐2 viral load was 9.2 RU, individuals with fewer CD4+ presented higher HSV‐2 viral load. The qPCR method is reproducible and has optimal reaction efficiency.

Detección de anticuerpos contra VIH a partir de muestras de sangre seca en papel filtro

Senor editor : En los ultimos anos se ha incrementado el uso de muestras de sangre seca en papel filtro (dried blood spots, DBS) para detectar anticuerpos contra virus de la hepatitis C (VHC), virus dengue y VIH, entre otros...

Prevalencia de anticuerpos frente a parotiditis en niños y adolescentes a dos años de haberse introducido la vacuna SRP

Resumen: Objetivo: Evaluar la prevalencia de anticuerpos antiparotiditis en ninos y adolescentes de Mexico, a dos anos de haberse introducido la vacuna SRP. Material y metodos: Se estudiaron 2111 ninos (1-9 anos) y 2484 adolescentes (10-19 anos). Se evaluaron anticuerpos IgG con un kit comercial de ELISA indirecto. Resultados: La seroprevalencia fue 70.6% (IC95% 69.3-71.9) y resulto mayor en adolescentes (83.0%, IC95% 81.5-84.5) que en ninos (56.0%, IC95% 53.9-58.11) (OR 3.83; IC95% 3.34-4.39, p=0.0000000). Los ninos de 1 a 2 y de 6 a 9 anos, que a partir de 1998 formaron parte del grupo blanco de vacunacion vs parotiditis, tuvieron mayor seroprevalencia que el grupo de 3 a 5 anos no vacunado. Conclusiones: La seropositividad en ninos de 1 a 2 y de 6 a 9 anos fue probablemente atribuible a vacunacion durante 1998-2000 y la de otros grupos etarios a exposicion natural relacionada con el tiempo transcurrido en cada cohorte de nacimientos hasta el reclutamiento al estudio.

The hidden burden of Chikungunya in central Mexico: results of a small-scale serosurvey

OBJECTIVE To estimate the seroprevalence of CHKV antibodies and assess correlates of seropositivity at a small geographical scale. MATERIALS AND METHODS A community-based serosurvey of 387 households in Puente de Ixtla, Morelos (central Mexico). Serum IgG antibodies to CHKV were detected by immunoassay. RESULTS From 27 April to 29 May 2016, we interviewed and collected blood samples from 387 individuals at the same number of households. A total of 114 (29.5%) participants were seropositive to CHK, 36 (31.6%) of them reported no symptoms of CHKV infection within 12 months before the survey. CONCLUSIONS The estimated seroprevalence to CHKV antibodies was higher than expected by the small number of confirmed cases of CHKV infection reported in Mexico by the National Surveillance System.