[Native and non-native antigen to determine the seroprevalence of Trypanosoma cruzi in pregnant women from the state of Morelos, Mexico]. / Antígeno nativo y no nativo para determinar la seroprevalencia de Trypanosoma cruzi en mujeres embarazadas en el estado de Morelos, México.

BACKGROUND: Chagas disease is a globally important chronic systemic parasitic infection caused by Trypanosoma cruzi. AIM: To determine the prevalence of antibodies against T cruzi in pregnant women from the state of Morelos, México. METHODS: 1,620 sera from pregnant women were analyzed using two serological tests: ELISAc (native crude antigen) and ELISAr (recombinant, non-native antigen). Reactive samples were subsequently analyzed by indirect hemagglutination (IHA). Two detection approaches were used, in parallel (reactive samples by any method are positive) and serial (samples confirmed by IHA are positive). Sociodemographic and health factors associated with the presence of antibodies against T cruzi were evaluated using 95% odds ratios. RESULTS: A seroprevalence of 4.87% was obtained with parallel diagnosis and 0.43% in series. From the parallel results, the women who were attended at the general hospitals of Tetecala and Jojutla had respectively 2.2 and 2.0 times greater chance of presenting antibodies against T cruzi compared to the women who were attended at the General Hospital of Cuautla. CONCLUSION: The prevalence of antibodies against T cruzi in pregnant women from the state of Morelos fluctuated between 0.43 and 4.87%, depending on the antigen and the approach used. It is necessary to continue with the surveillance of the seroprevalence of antibodies against T cruzi in pregnant women from the state of Morelos, Mexico, using the techniques with the highest sensitivity and specificity available.

Antígeno nativo y no nativo para determinar la seroprevalencia de Trypanosoma cruzi en mujeres embarazadas en el estado de Morelos, México / Native and non-native antigen to determine the seroprevalence of Trypanosoma cruzi in pregnant women from the state of Morelos, Mexico

INTRODUCCIÓN: La enfermedad de Chagas es una infección parasitaria crónica sistémica, de importancia global, causada por Trypanosoma cruzi. OBJETIVO: Determinar la prevalencia de anticuerpos contra T cruzi en mujeres embarazadas en el estado de Morelos, México. MATERIALES Y MÉTODOS: Se analizaron 1.620 sueros de mujeres embarazadas mediante dos pruebas serológicas: ELISAc (antígeno crudo nativo) y ELISAr (antígeno recombinante, no nativo). Las muestras reactivas se analizaron posteriormente mediante hemaglutinación indirecta (HAI). Se utilizaron dos enfoques de detección, en paralelo (son positivas las muestras reactivas por cualquier método) y en serie (son positivas las muestras confirmadas por HAI). Se evaluaron factores sociodemográficos y de salud asociados a la presencia de anticuerpos contra T. cruzi mediante razones de momios al 95%. RESULTADOS: Se obtuvo una seroprevalencia de 4,87% con el diagnóstico en paralelo y de 0,43% en serie. A partir de los resultados en paralelo las mujeres que fueron atendidas en los hospitales generales de Tetecala y Jojutla tuvieron, respectivamente, 2,2 y 2,0 veces mayor posibilidad de presentar anticuerpos contra T cruzi con respecto a las mujeres que fueron atendidas en el Hospital General de Cuautla. CONCLUSIÓN: La prevalencia de anticuerpos contra T cruzi en mujeres embarazadas en el estado de Morelos fluctuó entre 0,43 y 4,87%, según el antígeno y el abordaje utilizado. Es necesario continuar con la vigilancia de la seroprevalencia de anticuerpos contra T cruzi en mujeres embarazadas en el estado de Morelos, México, con las técnicas de mayor sensibilidad y especificidad disponibles.

BACKGROUND: Chagas disease is a globally important chronic systemic parasitic infection caused by Trypanosoma cruzi. AIM: To determine the prevalence of antibodies against T cruzi in pregnant women from the state of Morelos, México. METHODS: 1,620 sera from pregnant women were analyzed using two serological tests: ELISAc (native crude antigen) and ELISAr (recombinant, non-native antigen). Reactive samples were subsequently analyzed by indirect hemagglutination (IHA). Two detection approaches were used, in parallel (reactive samples by any method are positive) and serial (samples confirmed by IHA are positive). Sociodemographic and health factors associated with the presence of antibodies against T cruzi were evaluated using 95% odds ratios. RESULTS: A seroprevalence of 4.87% was obtained with parallel diagnosis and 0.43% in series. From the parallel results, the women who were attended at the general hospitals of Tetecala and Jojutla had respectively 2.2 and 2.0 times greater chance of presenting antibodies against T cruzi compared to the women who were attended at the General Hospital of Cuautla. CONCLUSION: The prevalence of antibodies against T cruzi in pregnant women from the state of Morelos fluctuated between 0.43 and 4.87%, depending on the antigen and the approach used. It is necessary to continue with the surveillance of the seroprevalence of antibodies against T cruzi in pregnant women from the state of Morelos, Mexico, using the techniques with the highest sensitivity and specificity available.

Low Seroprevalence of Measles-Specific IgG in Children of Three Ethnic Groups from Mexico: Influence of Age, Sex, Malnutrition and Family Size.

BACKGROUND: The reemergence of measles represents a public health problem. The aim of the study was to determine the seroprevalence of IgG antibodies against measles in children of three ethnic groups in southern Mexico and the nutritional status and demographic risk factors associated. METHODS: A cross-sectional study in 416 school-age children, 207 belonging to the Tlapaneco ethnic group, 101 to the Mixteco group and 108 were considered Mestizo. Sociodemographic data were collected, an anthropometric evaluation of the children was performed and a fasting blood sample was obtained from each child for the measurement of measles IgG antibodies by Enzyme-Linked Immunosorbent Assay (ELISA). RESULTS: From the total sample, 59% of the children were seropositive for IgG antibodies against measles; in contrast, 41% lacked IgG antibodies. Measles antibody seropositivity was higher in girls (64%). 90.5% of 6-year-old children had higher antibodies seroprevalence, compared to the children between 10 and 13 years old (45.5%). In the three ethnic groups, age was negatively correlated with the index standard ratio (ISR) of measles antibody levels and the families with ≥8 members showed less seropositivity. According to the antibodies levels, most of the positive cases remained around 1 Standard Deviation (SD) of the ISR values and no underweight children had antibody levels above 2 SD. CONCLUSIONS: The Anti-Measles serological coverage is low in children of three ethnic groups from Southern Mexico and the age, sex, malnutrition and family size are associated factors. Therefore, it is important to strengthen immunization campaigns, principally in vulnerable groups.

Evaluation of an HIV recent infection testing algorithm with serological assays among men who have sex with men in Mexico.

BACKGROUND: Human immunodeficiency virus (HIV) incidence should be calculated in cross-sectional studies using recent infection testing algorithms (RITA) that consider clinical variables and serological test results such as enzyme-linked immunosorbent assay (ELISA) and dried blood spot (DBS) analysis. METHODS: The correlation between serum samples and DBS was evaluated using two commercial ELISA kits: SediaTM BED HIV-1 Incidence EIA (BED-Sedia) and Maxim HIV-1 Limiting Antigen Avidity (LAg-Avidity). Eight different RITAs were developed; all of them included serological assays. A combination of the variables viral load, antiretroviral therapy (ART) and CD4 count was used to build the RITAs. The sensitivity, specificity, Youden index, predictive positive value, predictive negative value, false recent rate (FRR) and false long-term rate were evaluated. RESULTS: The correlations between serum samples and DBS were 0.990 and 0.867 for BED-Sedia and LAg-avidity, respectively. Using only serological assays, the Youden index was higher for LAg-avidity than BED-Sedia (82.1-83.0% versus 69.2-69.6%). The best RITA was ART-serology, which showed a Youden index of 91.2-93.9% and FRR of 1.8-2.2%. CONCLUSIONS: Using DBS samples to determine HIV incidence is a good tool for epidemiological surveillance. The RITA that included ART and serological tests (BED-Sedia or LAg-avidity) showed the highest sensitivity and specificity and a low FRR.

Performance of ELISA and Western blot to detect antibodies against HSV-2 using dried blood spots.

BACKGROUND AND AIMS: Herpes simplex virus type 2 (HSV-2) is a sexually transmitted agent and is detected worldwide. HSV-2 is the main cause of genital ulcers and is diagnosed mainly with serological tests. The objective of current study was to evaluate the use of DBS samples to detect HSV-2 antibodies using commercial ELISA and Western blot tests. MATERIALS AND METHODS: IgG-G2 ELISA (Human® Diagnostics, Germany) and Western blot IgG/IgM (EUROLINE-WB, Euroimmun® Germany) tests were modified to use DBS samples. Samples were processed by both methods to determine ELISA cutoff points using ROC curves. ELISA was performed with 100µl and the Western blot with 200µl of eluted DBS. A 1:5 dilution was used and the incubation times were increased for the Western blot. RESULTS: 908 DBS samples were processed and the following cutoff points were determined: negative (0-3.79), undetermined (3.8-4.6) and positive (≥4.61), with sensitivity and specificity close to 95%. CONCLUSION: Modifications of the cutoff points of the ELISA test were obtained with technical adjustments done to detect HSV-2 antibodies by ELISA and Western blot using DBS samples.

Changes in cardiovascular risk and clinical outcomes in a HIV/AIDS cohort study over a 1-year period at a specialized clinic in Mexico.

INTRODUCTION: The third report of the National Cholesterol Education Program guidelines recommends calculating the 10-year morbidity of atherosclerotic cardiovascular disease (ASCVD) using risk calculators when treating high blood cholesterol in adults. We analyzed the changes in cardiovascular risk (CVR) among Mexican patients with HIV. PATIENTS AND METHODS: This observational, prospective cohort study compared the CVR after 1 year of antiretroviral treatment among 460 HIV patients from a Mexican clinic. Changes using the ASCVD risk estimator and changes in clinical outcomes were analyzed. The results were categorized as low or high CVR using a cutoff of 7.5%. RESULTS: The CVR initially had a median of 2.3% (interquartile range [IQR]: 1%-4.8%), which changed to 2.4% (IQR: 1.5%-5.5%) after 1 year (P=0.001). After CVR stratification, we found that 84.3% of the patients had a low CVR, and 18% in this subgroup had metabolic syndrome (MS). Moreover, 15.7% had high CVR, and 47% in this subgroup had MS. The 4.3% of patients had an increase in CVR from the low to high subgroup, and 2.6% had a decrease in CVR from the high to low subgroup. Out of all patients, 22.3% had MS. CONCLUSION: More than 50% of the population had an increase in CVR after 1 year. Of these patients, 4.3% changed from the low to high CVR group. Although the guidelines proposed different time periods for performing CVR estimations, this study showed that such assessments offered valuable clinical data over a relatively short-term period.

College women, HPV genotyping and sexual behavior before HPV vaccination: Results from samples stored for a long time.

HPV is the sexually transmitted agent most common among young people, like college students. The aim of study was to associate sexual behavior characteristics of women with HPV, detected in genital samples taken before the introduction of the HPV vaccine. Female students during 2001-2005 donated genital samples and the samples were re-analyzed in 2013 for HPV genotyping by RT-PCR. The frozen storage of the students' genital samples allowed the detection of HPV DNA and its genotyping after years of sample collection. HPV prevalence was 22%, HPV16 3.9%, and HPV18 1.1%. Age, multiple sexual partners and the partner's age at first sexual intercourse were significantly associated to HPV. Students with ≥ 3 sexual partners and who did not use condom had 12.8 higher odds of being HPV positive. These results made possible the analysis of HPV prevalence changes, before HPV vaccine introduction.

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 ß-globin was determined as 3.3 × 10-5 ng/µL, and for HSV-2 at 6.0 × 10-6 ng/µL. The efficiency for ß-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.

[Proposal for early detection of ethanol consumption in students of the Universidad Autónoma del Estado de Morelos]. / Propuesta para la detección temprana del consumo de etanol en estudiantes de la Universidad Autónoma del Estado de Morelos.

The present study determined through analytic techniques the quantification of some biomarkers that have been useful to detect early ethanol consumption in a college population. A group of 117 students of recent entry to the Universidad Autónoma del Estado de Morelos was analyzed. The enzyme determination of aspartate aminotransferase, alanine aminotransferase, and gamma glutamyltransferase as metabolic markers of ethanol, as well as the carbohydrate-deficient transferrin (CDT) detected by high chromatographic liquid (up to 1.8% of CDT), allowed us to identify that 6% of the college population presented a potential risk of alcohol consumption. The use of the biochemical-analytical method overall with the psychological drug and a risk factor instrument established by the Universidad Autónoma del Estado de Morelos permit us to identify students whose substance abuse consumption puts their terminal efficiency at risk as well as their academic level. The timely detection on admission to college can monitor and support a student consumer's substance abuse.

[Trend analysis of acquired syphilis in Mexico from 2003 to 2013]. / Análisis de la tendencia de sífilis adquirida en México durante el periodo 2003-2013.

OBJECTIVE: To identify the population group in which syphilis increase was concentrated. MATERIALS AND METHODS: The information was collected from the Mexico health statistical yearbooks. The information disaggregated by sex, age group and state during the period 2003 to 2013 was used to form different databases. Linear regression analysis with confidence interval at 95% was used to evaluate changes over time in different population groups. RESULTS: An increase of 0.67 cases per 100,000 population (95%CI 0.30-1.04) in men was detected from 2010. The increase was concentrated in each group of 20-24 and 25-44. The highest incidence of acquired syphilis was reported in the last two years: 2012 and 2013. The last year reported a 1.85 times higher incidence than reported in 2003. Aguascalientes, Distrito Federal, Durango, Mexico, Oaxaca, Puebla, Quintana Roo, Yucatan and Zacatecas reported that syphilis increased during the study period. CONCLUSION: Acquired syphilis may be reemerging in our country among young men; this increase is not uniform across the country, it is necessary to focus intervention measures for this sexually transmitted infection.

Análisis de la tendencia de sífilis adquirida en México durante el periodo 2003-2013 / Trend analysis of acquired syphilis in Mexico from 2003 to 2013

Objetivo. Identificar el grupo poblacional en el que se concentra el incremento de sífilis ocurrido durante los últimos años. Material y métodos. A partir de información obtenida de los Anuarios de Morbilidad de la Secretaría de Salud, se conformaron diversas bases de datos con información desagregada por sexo, grupo de edad y entidad federativa durante el periodo de 2003 a 2013. Mediante análisis de regresión lineal, se estimó el incremento con intervalos de confianza a 95%; se evaluaron los cambios a través del tiempo en los diversos grupos poblacionales analizados. Resultados. A partir de 2010 hay un incremento de 0.67 casos por 100000 habitantes (IC95% 0.30-1.04) entre los hombres, que se concentra en individuos de 20 a 24 y de 25 a 44 años. Las mayores incidencias de sífilis adquirida se reportaron en los dos últimos años: 2012 y 2013; este último año registró una incidencia 1.85 veces mayor a la reportada en el año 2003. Entidades como Aguascalientes, Distrito Federal, Durango, México, Oaxaca, Puebla, Quintana Roo, Yucatán y Zacatecas reportaron incrementos de sífilis adquirida durante el periodo de estudio. Conclusión. La sífilis adquirida aparentemente está reemergiendo en México entre hombres jóvenes, incremento que no es homogéneo en el país, por lo que es necesario focalizar medidas de intervención para esta infección de transmisión sexual.

Objective. To identify the population group in which syphilis increase was concentrated. Materials and methods. The information was collected from the Mexico health statistical yearbooks. The information disaggregated by sex, age group and state during the period 2003 to 2013 was used to form different databases. Linear regression analysis with confidence interval at 95% was used to evaluate changes over time in different population groups. Results. An increase of 0.67 cases per 100000 population (95%CI 0.30-1.04) in men was detected from 2010. The increase was concentrated in each group of 20-24 and 25-44. The highest incidence of acquired syphilis was reported in the last two years: 2012 and 2013. The last year reported a 1.85 times higher incidence than reported in 2003. Aguascalientes, Distrito Federal, Durango, Mexico, Oaxaca, Puebla, Quintana Roo, Yucatan and Zacatecas reported that syphilis increased during the study period. Conclusion. Acquired syphilis may be reemerging in our country among young men; this increase is not uniform across the country, it is necessary to focus intervention measures for this sexually transmitted infection.

Serum leptin is associated with metabolic syndrome in obese Mexican subjects.

BACKGROUND: The metabolic syndrome (MetS) is a cluster of metabolic abnormalities including insulin resistance, dyslipidemia, high blood pressure, and abdominal adiposity. Obese patients develop leptin resistance, and an increased waist circumference (WC) due to deposition of abdominal fat. The aim of this study was to evaluate the association between circulating leptin levels and MetS among sample adult Mexican workers. METHOD: A total of 204 workers aged 20-56 were evaluated. Anthropometric index, blood pressure, fasting plasma glucose, and lipid profile were measured by spectrophotometric methods. Fasting insulin and leptin were measured by inmunoenzimatic methods. Furthermore, homeostasis model assessment for insulin resistance (HOMA-IR) was calculated. RESULTS: The prevalence of MetS according to the ATP-III criteria was 33.8% and leptin concentrations were 2.5 times higher in women than men. Subjects with MetS had higher levels of leptin (26.7 ± 13.7) compared with those without MetS (20.1 ± 13.9; P <0.001). Leptin increased significantly while BMI increased as well (normal 14.0 ± 8.9, overweight 22.7 ± 11.7 and obese 31.4 ± 14.6) in addition to other variables such as WC, HDL-C, insulin levels, and HOMA index. Each component of MetS was stratified by sex and submitted by linear regression with a 95% of accuracy. The 50% and 53% of the BMI is explained by the concentration of leptin in men and women, respectively (P < 0.001). CONCLUSION: This study found that leptin was associated with the MetS, especially in obesity and insulin resistance, indicating a high risk for university workers to develop hypertension, DM2, and cardiovascular disease.

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.

Serosurvey of antibodies against Toxoplasma gondii and Neospora caninum in white-tailed deer from Northern Mexico.

The objective of this study was to determine the seroprevalence of Toxoplasma gondii and Neospora caninum in white-tailed deer from Northern Mexico. Sera from 532 white-tailed deer (Odocoileus virginianus) from three Northern states of Mexico were assayed for antibodies to T. gondii by ELISA and western blot. From these samples, 368 were available to test for N. caninum antibodies by ELISA. The overall prevalence for T. gondii antibodies was 13.9% (74/532; CI(95) 11-17) and for N. caninum 8.4% (31/368; CI(95) 6-12). There was a significant association between positive ELISA results for T. gondii, with management factors within ranches, such number of deer per hectare and geographic location of deer, but none for N. caninum. T. gondii infection in the deer from Guerrero, Coahuila had an increased risk than those from Nuevo Laredo, Tamaulipas (OR, 8.3; CI(95) 1.9-35.4; P<0.05) and ranches with one deer in 15 ha had increased risk of positive association (OR, 2.61; CI(95) 1.5-4.4; P<0.05). These findings may have environmental or public health implications because venison can be an important meat source of T. gondii infections for humans and feral cats.

Human papillomavirus incidence and risk factors among Mexican female college students.

OBJECTIVE: To determine the factors associated with high-risk human papillomavirus (HR-HPV) and its incidence in a cohort of female college students, with particular emphasis on the use of condoms. METHODS: A cohort was created during 2001 to 2005. The students signed informed consent, answered a questionnaire, and provided a vaginal scrape to detect HR-HPV. Incidences were estimated and risk factors were evaluated using Cox proportional risk model. The variable condom use was constructed based on the following 3 measurements: relative frequency throughout one's lifetime, use during the first sexual relationship, and use during the last sexual relationship. RESULTS: A total of 237 women participated, providing 395.6 person-years of follow-up. An incidence of 15.9 HR-HPV infection per 100 person-years was estimated and the factors associated with HR-HPV infection were found to be self-reported sexually transmitted infections (RR = 2.7), use of emergency contraception pill (ECP) (RR = 2.0), and having 2 or more sexual partners (RR = 1.9). University students using the ECP demonstrated more risky sexual behavior than nonusers. Women with 2 or more sexual partners who reported inconsistent condom use had 3.8 times the rate of HR-HPV infection. CONCLUSIONS: The incidence for HR-HPV in this cohort of Mexican female college students is comparable to that found in the United States and Canada. The results suggest that the consistent use of condoms is a protective factor against HR-HPV, especially for women with multiple sexual partners and/or those who use the ECP.

Population-based prevalence of antibodies against herpes simplex virus type 2 and socio-demographic characteristics in Mexico.

Although several studies to evaluate the correlates between seroprevalence of herpes simplex virus type 2 (HSV-2) and sexual practices have been carried out with specific groups in Mexico, none has evaluated overall seroprevalence among the general population or its relationship with socio-demographic characteristics. The National Health Survey performed during 2000 in Mexico studied a multi-stage, stratified, cluster sample of the general population. Characteristics of the adult population, such as age, formal education, marital status, residence, age at first intercourse and categories of HSV-2 seroprevalence distribution by state, were studied. Specific antibodies against HSV-2 were determined by ELISA. The weighted seroprevalence of HSV-2 was 17.3% (95% CI 15.8-18.8) and showed significant variations according to age, sex, marital status, residence, age at first intercourse and categories of HSV-2 seroprevalence distributed by state. In conclusion, the prevalence of HSV-2 varied significantly according to the socio-demographic and geographic characteristics of the adult population in Mexico. These results suggest that variations in HSV-2 seroprevalence could be related to socio-economic and sexual behavior characteristics of the population. However, to support these assertions, further work could focus on the study of sexual behavior and its relation with the socio-economic distribution of the population in Mexico.

Different patterns of herpes simplex virus type 1 infection among college students from Cuernavaca, Mexico.

The goal of this study was to determine herpes simplex virus type 1 (HSV-1) seroprevalence among college students from Morelos State University, Mexico; and to correlate their demographic and sexual behaviour characteristics with HSV-1 infection. Demographic characteristics were associated with HSV-1 among female students. Among male students, sexual behaviour characteristics were associated with HSV-1 seroprevalence. Male students who practised oral sex and did not always use a condom presented higher rates of HSV-1 infection (76.9%) than students who did not have oral sex (52.2%). A different pattern of HSV-1 infection depends on gender among Mexican students analysed.

Core group approach to identify college students at risk for sexually transmitted infections

OBJETIVO: Identificar al grupo core de infecciones de transmisión sexual (ITS) en una población de estudiantes universitarios mexicanos. MÉTODOS: Se realizó un estudio transversal en una muestra por conveniencia que incluyó 711 estudiantes de una universidad pública de Morelos, México, entre 2001 y 2003. Las características sociodemográficas y de comportamiento sexual se obtuvieron mediante un cuestionario auto-aplicado. La infección por el Virus del herpes simple tipo 2 (VHS-2) se determinó en pruebas de sangre. El número de parejas sexuales durante el último año y el consumo de cocaína, fueron indicadores utilizados para construir la variable dependiente "nivel de riesgo para adquirir ITS" que tuvo tres categorías: bajo, medio y alto riesgo (grupo core). Mediante un análisis multinomial se evaluó si las características sociodemográficas y de comportamiento sexual estuvieron relacionadas con la variable dependiente. RESULTADOS: Se encontró una relación significativa entre la seroprevalencia de VHS-2 y la variable dependiente encontrando frecuencias de 13 por ciento, 5.6 por ciento y 3.8 por ciento en las categorías de alto, medio y bajo riesgo, respectivamente. Los resultados mostraron diferencias de género en la constitución del grupo core. En comparación con las mujeres, los hombres iniciaron su vida sexual a más temprana edad, reportaron mayor número de parejas sexuales, mayores niveles de consumo de alcohol y drogas, mayor frecuencia de contacto sexual con trabajadoras sexuales, intercambio de sexo por dinero, relaciones con parejas ocasionales y concurrentes. CONCLUSIONES: Los resultados sugieren que existen características contextuales que influyen en el comportamiento sexual. En México la concepción cultural de la sexualidad está conformada por diferencias marcadas entre hombres y mujeres, donde los primeros tienen un comportamiento sexual de riesgo mayor que las mujeres.