Polymorphisms of CCR5, IL-6, IFN-γ and IL-10 genes in Cuban HIV/AIDS patients.

INTRODUCTION: Genetic studies have shown associations of several single nucleotide polymorphisms (SNP) with different rates of progression and variation in susceptibility to HIV infection. This study aimed to estimate the frequency of ccr5Δ32, IL-6-174G/C, IFN-γ+874T/A and IL-10-1082A/G polymorphisms in Cuban HIV-infected patients and a group of sero-discordant couples to assess their influence on risk and disease progression. METHODS: A cross-sectional study was carried out on 120 subjects registered at the Institute of Tropical Medicine «Pedro Kour¼ (IPK) and the Ameijeiras Hospital from June 2018 until December 2019. The amplification of fragments of the ccr5, IL-6, IFN-γ and IL-10 genes was performed by polymerase chain reaction followed by identification of polymorphisms using the restriction fragment length polymorphism analysis for IL-6 with the restriction enzymes Nla III. Amplification Refractory Mutation System was used for IFN-γ and IL-10 genes. RESULTS: The allelic and genotypic distributions of the genes ccr5, IL-6, IFN-γ and IL-10 did not differ significantly between the two groups. Cell counts and plasma viral load values did not differ significantly between genotypes of the ccr5, IL-6, IFN-γ and IL-10 genes. Only the IL-6 GC genotype was associated with higher viral load values. The combination of alleles of the four considered SNPs showed a highly significant increase in the risk of HIV infection for one of them, but with a very low frequency (<1%). CONCLUSION: This study contributes to evaluating the frequency of these polymorphisms and their influence on biomarkers of the progression of HIV infection in the Cuban HIV-population.

The influence of hospital antimicrobial use on carbapenem-non-susceptible Enterobacterales incidence rates according to their mechanism of resistance: a time-series analysis.

BACKGROUND: Carbapenem non-susceptible Enterobacterales (CNSE) can be broadly divided into those that produce carbapenemases (carbapenemase-producing Enterobacterales (CPE)), and those that harbour other mechanisms of resistance (non-carbapenemase-producing CNSE (NCP-CNSE)). AIM: To determine the predictors of CNSE nosocomial incidence rates according to their mechanism of resistance. METHODS: A time-series analysis was conducted (July 2013 to December 2018) to evaluate the relationship in time between hospital antibiotic use and the percentage of adherence to hand hygiene with the CNSE rates. FINDINGS: In all, 20,641 non-duplicated Enterobacterales isolates were identified; 2.2% were CNSE. Of these, 48.1% and 51.9% were CPE and NCP-CNSE, respectively. Of the CPE, 78.3% possessed a blaOXA-232 gene. A transfer function model was identified for CNSE, CPE, and OXA-232 CPE that explained 20.8%, 19.3%, and 24.2% of their variation, respectively. According to the CNSE and CPE models, an increase in piperacillin-tazobactam (TZP) use of 1 defined daily dose (DDD) per 100 hospital patient-days (HPD) would lead to an increase of 0.69 and 0.49 CNSE and CPE cases per 10,000 HPD, respectively. The OXA-232 CPE model estimates that an increase of 1 DDD per 100 HPD of TZP use would lead to an increase of 0.43 OXA-232 CPE cases per 10,000 HPD. A transfer function model was not identified for NCP-CNSE, nor was there an association between the adherence to handhygiene and the CNSE rates. CONCLUSION: The use of TZP is related in time with the CPE nosocomial rates, mostly explained by its effect on OXA-232 CPE.

Expression of a symbiosis-specific gene in Symbiodinium type A1 associated with coral, nudibranch and giant clam larvae.

Symbiodinium are responsible for the majority of primary production in coral reefs and found in a mutualistic symbiosis with multiple animal phyla. However, little is known about the molecular signals involved in the establishment of this symbiosis and whether it initiates during host larval development. To address this question, we monitored the expression of a putative symbiosis-specific gene (H+-ATPase) in Symbiodinium A1 ex hospite and in association with larvae of a scleractinian coral (Mussismilia hispida), a nudibranch (Berghia stephanieae) and a giant clam (Tridacna crocea). We acquired broodstock for each host, induced spawning and cultured the larvae. Symbiodinium cells were offered and larval samples taken for each host during the first 72 h after symbiont addition. In addition, control samples including free-living Symbiodinium and broodstock tissue containing symbionts for each host were collected. RNA extraction and RT-PCR were performed and amplified products cloned and sequenced. Our results show that H+-ATPase was expressed in Symbiodinium associated with coral and giant clam larvae, but not with nudibranch larvae, which digested the symbionts. Broodstock tissue for coral and giant clam also expressed H+-ATPase, but not the nudibranch tissue sample. Our results of the expression of H+-ATPase as a marker gene suggest that symbiosis between Symbiodinium and M. hispida and T. crocea is established during host larval development. Conversely, in the case of B. stephanieae larvae, evidence does not support a mutualistic relationship. Our study supports the utilization of H+-ATPase expression as a marker for assessing Symbiodinium-invertebrate relationships with applications for the differentiation of symbiotic and non-symbiotic associations. At the same time, insights from a single marker gene approach are limited and future studies should direct the identification of additional symbiosis-specific genes, ideally from both symbiont and host.

Importance of tissue sampling, laboratory methods, and patient characteristics for detection of Pneumocystis in autopsied lungs of non-immunosuppressed individuals.

To understand the epidemiological significance of Pneumocystis detection in a lung tissue sample of non-immunosuppressed individuals, we examined sampling procedures, laboratory methodology, and patient characteristics of autopsy series reported in the literature. Number of tissue specimens, DNA-extraction procedures, age and underlying diagnosis highly influence yield and are critical to understand yield differences of Pneumocystis among reports of pulmonary colonization in immunocompetent individuals.

Relationship between lymphocyte DNA fragmentation and dose of iron oxide (Fe2O3) and silicon oxide (SiO2) nanoparticles.

At present, the use of nanoparticles is a controversial topic, especially when analyzing their effects in human tissues. Nanoparticles (NPs) can cause oxidative stress by increasing membrane lipids peroxidation and reactive oxygen species, and decreasing intracellular glutathione. Oxidative stress plays an important role in cell signaling and inflammatory responses. It can result in genotoxicity, affect cell proliferation, and induce DNA damage. The objective of this study is to evaluate the genotoxic potential of NPs in lymphocyte DNA. Wistar female rats (N = 45) were sorted in three randomized groups as follows: Group 1 (N = 20); Group 2 (N = 20) and a control group (N = 5). A single dose of iron oxide (Fe2O3) and silicon oxide (SiO2) NPs dissolved in saline solution were administered orally to the rats. Cardiac puncture was performed to extract peripheral blood for genotoxic analysis. DNA fragmentation for lymphocytes was performed. Control rats showed a fragmentation percentage of 11.20 ± 2.16%. Rats exposed to SiO2 and Fe2O3 NPs for 24 h showed statistically significant differences in DNA fragmentation percentages as compared with that of the control group. A lineal dose-response correlation between genotoxic damage and exposure to SiO2 and Fe2O3 NPs was found (r2 = 0.99 and 0.98 for SiO2 and Fe2O3, respectively). In conclusion, we found that exposure to Fe2O3 and SiO2 NPs can cause DNA fragmentation in lymphocytes in a dose-dependent manner.

Preparation and preclinical evaluation of (66)Ga-DOTA-E(c(RGDfK))2 as a potential theranostic radiopharmaceutical.

INTRODUCTION: Integrin αvß3 plays an important role in angiogenesis and is over-expressed in tumoral endothelial cells and some other tumor cells. RGD (Arg-Gly-Asn) peptides labeled with (68)Ga (t1/2=68min) have showed good characteristics for imaging of αvß3 expression using positron emission tomography (PET). Gallium-66 has been proposed as a PET imaging alternative to (68)Ga and given the unique high energy of its emitted positrons (Emax 4.15MeV) it may also be useful for therapy. The aim of this research is to prepare [(66)Ga]DOTA-E-[c(RGDfK)]2 and evaluate in mice its potential as a new theranostic radiopharmaceutical. METHODS: High specific activity (66)Ga was produced via the (66)Zn(p,n) reaction, and the labelling method of DOTA-E-[c(RGDfK)]2 with (66)Ga was optimized. Radiochemical purity was determined by TLC, and in vitro stability and protein binding were determined. Serial microPET imaging and biodistribution studies were carried out in nude mice bearing C6 xenografts. Radiation absorbed dose estimates were based on the biodistribution studies, where tumor and organs of interest were collected at 0.5, 1, 3, 5 and 24h post-injection of [(66)Ga]DOTA-E-[c(RGDfK)]2. RESULTS: Our results have shown that [(66)Ga]DOTA-E-[c(RGDfK)]2 can be prepared with high radiochemical purity (>97%), specific activity (36-67GBq/µmol), in vitro stability, and moderate protein binding. MicroPET imaging up to 24 post-injection showed contrasting tumors reflecting αvß3-targeted tracer accumulation. Biodistribution studies and dosimetry estimations showed a stable tumor uptake, rapid blood clearance, and favorable tumor-to-tissue ratios. CONCLUSIONS: The peptide conjugated DOTA-E-[c(RGDfK)]2 labeled with (66)Ga may be attractive as a theranostic agent for tumors over-expressing αvß3 integrins.

[Evolution of the intake and nutritional status of zinc, iron and copper in women undergoing bariatric surgery until the second year after surgery]. / Evolución de la ingesta y del estado nutricional de zinc, hierro y cobre en mujeres sometidas a cirugía bariátrica hasta el segundo año postoperatorio.

INTRODUCTION: Bariatric surgery allows a significant reduction in weight and improvement of comorbidities associated with obesity in the long term, but it can also adversely affect the nutritional status of some micronutrients. OBJECTIVES: To evaluate changes in intake and parameters of nutritional status of zinc, iron and copper in patients undergoing Roux-en-Y gastric bypass (GBP) or sleeve gastrectomy (SG), until the second postoperative year. METHODS: We prospectively studied 45 women undergoing GBP or SG (mean age 35.2 ± 8.4 years, mean BMI 39.8 ± 4.0 kg/m²), every 6 months We measured intake and status indications nutritional zinc, iron and copper, and annually evaluated body composition. The contribution of minerals through supplements represented twice the recommended intake for a healthy woman in patients undergoing GT and three times for GBP. RESULTS: 20 women underwent GBP and 25 SG. In both groups there was a significant reduction in weight and body fat percentage, which was maintained until the second postoperative year. Women who have had a greater commitment GBP nutritional status of zinc, iron and copper, that patients undergoing SG. CONCLUSIONS: Gastric bypass Roux-Y produces a greater commitment of nutritional status of zinc, iron and copper sleeve gastrectomy. It should evaluate whether administration of supplementation fractional improve the absorption of these nutrients.

Pneumocystis jirovecii pneumonia in developing countries.

Pneumocystis pneumonia (PcP) is a serious fungal infection among immunocompromised patients. In developed countries, the epidemiology and clinical spectrum of PcP have been clearly defined and well documented. However, in most developing countries, relatively little is known about the prevalence of pneumocystosis. Several articles covering African, Asian and American countries were reviewed in the present study. PcP was identified as a frequent opportunistic infection in AIDS patients from different geographic regions. A trend to an increasing rate of PcP was apparent in developing countries from 2002 to 2010.

Identification of Avibacterium paragallinarum serovar B-1 from severe infectious coryza outbreaks in Panama.

The isolation and identification of Avibacterium paragallinarum serovar B-1 from severe infectious coryza outbreaks in broiler breeders in Panama is reported for the first time. Infectious coryza was absent for over a decade in the breeder farms area. Disease outbreaks were characterized by an up to 45% drop in egg production and increased mortality. Use of a commercial trivalent bacterin and a strengthened biosecurity program prevented outbreaks in susceptible flocks in the farm.

Detección sensible y específica de mycobacterium tuberculosis a partir de muestras clínicas, mediante la amplificación de un elemento repetitivo de la familia rep13e12 / Sensitive and specific detection of Mycobacterium tuberculosis from clinical samples by amplification of a repeated sequence of the REP13E12 family

Objetivos: Diseñar e implementar un método de PCR para la detección sensible y específica de M. tuberculosis, orientado al oportuno diagnóstico de la tuberculosis mediante su adecuada aplicación en muestras clínicas. Materiales y métodos: Se diseñaron oligonucleótidos específicos para la amplificación de un fragmento de 318pb luego de una alineación múltiple de secuencias REP13E12 de M. tuberculosis. Se realizó la estandarización del método de PCR y se evaluó la sensibilidad y especificidad diagnóstica utilizando muestras clínicas con diagnóstico baciloscópico y cultivo. Resultados: El REP13E12-PCR detectó hasta 100 fg de ADN genómico, fue específico para la detección del complejo M. tuberculosis y capaz de distinguirlos de micobacterias atípicas. Esta evaluación preliminar proporcionó 100% de sensibilidad y especificidad en muestras clínicas de pacientes con diagnóstico de TB. Conclusiones: La amplificación de REP13E12 mediante PCR es una alternativa para el diagnóstico rápido de pacientes con TB, especialmente en casos cuyo diagnóstico pueda ser dificultoso o poco claro mediante el uso de los métodos convencionales..

Objectives: To design and implement of PCR method for sensitivity and specific detection of M. tuberculosis oriented to opportune and correctly diagnosis of tuberculosis by the application on clinical specimens. Material an methods: Specific oligonucleotides for the amplification of a fragment of 318pb after a multiple alignment of sequences REP13E12 were designed. The PCR method was standarize and also the analytical and diagnostic sensibility and specifity was evaluate; using clinical samples with smear or culture diagnosis positive and negative. Results: The REP13E12-PCR detected up to 100 fg of genomic DNA. It was specific for the detection of complex M. tuberculosis and able to distinguish them of non-tuberculous mycobacteria. This preliminary evaluation provided 100% of sensitivity and specificity in sputum samples of patients with TB diagnosis. Conclusions: The REP13E12 amplification by PCR is an alternative method for the rapid diagnosis of patients with TB, especially for cases which difficult or unclear diagnosis by the gold standard technique.

Evaluación del impacto del desayuno escolar en el estado nutricional de los escolares / Assessment of school breakfast impact on the nutritional status of the schoolchildren

La carrera de Nutrición y Dietética, evaluó el impacto del desayuno escolar proporcionado por el Gobierno Municipal de La Paz, durante los periodos 2000 a 2001, para tal efecto, se desarrollaron siete componentes: evaluación del estado nutricional, consumo alimentario, análisis sensorial, aceptabilidad de la ración, promoción del desayuno escolar, educación y evaluación del impacto de la ración del desayuno escolar

Estudio de un brote intrahospitalario por salmonella typhimurium productora de beta-lactamasa de espectro extendido SHV-5 / Study of a hospital outbreak by enlarged SHV-5 spectrum beta-lactamase producing salmonella typhimurium

Antecedentes: Presencia de un brote intrahospitalario de Salmonella typhimurium productora de beta-lactamasas de espectro extendido ocurrido en el Hospital San Bartolome, entre el 17 de febrero y el 6 de marzo del año 2001. Objetivo: Identificar los mecanismos implicados en la transmisión de Salmonella typhimurium y caracterización de los genes asociados a la resistencia en beta-lactámicos. Diseño: Estudio clínico bacteriológico retrospectivo. Lugar: Hospital Nacional Docente Madre Niño (Honadomani) San Bartolomé. Materiales biológicos: Aislamientos bacterianos provenientes de pacientes lactantes. Intervenciones: Se determinó la diversidad genética de cinco aislamientos bacterianos provenientes de pacientes lactantes hospitalizados en la Unidad pediátrica del hospital, utilizando REP-PCR y fingerprint plasmídico. Previamente, se caracterizó la resistencia antimicrobiana, determinando la presencia de beta-lactamasa de espectro extendido mediante la prueba de sinergia de doble disco; la variante fue identificada por PCR secuenciamiento del gen blashv. Principales medidas de resultados: Presencia de genotipos, plásmidos y beta-lactamasa de Salmonella typhimurium. Resultados: Se determinó la presencia de dos genotipos en los aislamientos de Salmonella typhimurium; el caso índice (sensible) presentó un genotipo diferente al de otros aislamientos resistentes pertenecientes a pacientes hospitalizados. Se determinó la presencia en S. typhimurium de un plásmido de peso molecular elevado de tamaño distinto a los de K. pneumoniae, pero probablemente relacionado con una cepa de E. coli intrahospitalaria. Se encontró la beta-lactamasa de espectro extendido SHV- 5 en los aislamientos de S. typhimurium y E. coli. Conclusiones: El estudio sugiere que la diseminación de estas bacterias en los lactantes puede haber sido favorecida por varios factores que habrían intervenido en la transferencia de elementos genéticos responsables de la resistencia antimicrobiana.

Background: An ESBL Salmonella typhimurium outbreak occurred at San Bartolome hospital from February 17 through March 16, 2001. Objectives: To identify the mechanism involved in Salmonella typhimurium spread and genetic characterization of beta-lactamase resistance associated genes. Design: Clinical-bacteriologic retrospective study. Setting: San Bartolomé Mother Child Teaching National Hospital. Biologic materials: Bacterial isolations from lactating patients. Interventions: The genetic diversity was characterized from five bacterial isolates from infants admitted to the pediatric units, using REP-PCR and plasmid fingerprinting. We previously characterized the antimicrobial resistance, determining the presence of ESBL by the double disc diffusion method and the variant was identified by sequencing the gen blashv. Main outcome measures: Salmonella typhimurium genotypes, plasmids and beta-lactamase presence. Results: We found two different genotypes among the Salmonella typhimurium isolates; the index case (susceptible) showed a different genotype and the other isolates coming from hospitalized children were resistant. One of the S. typhimurium plasmids had a heavier molecular weight than K. pneumoniaeÆs but as heavy as the hospital acquired E. coli isolates plasmids. We found the ESBL SHV-5 in both S. typhimurium y E. coli isolates. Conclusions: This report suggests that the bacteria spread among infants could be facilitated by many factors playing different roles in the genetic material transfer responsible of the microbial resistance.

Occurrence of bacterial indicators and bacteriophages infecting enteric bacteria in groundwater in different geographical areas.

AIMS: The aim of this research was to determine the suitability of coliphages (bacteriophages) for assessing the microbial quality of groundwater. METHODS AND RESULTS: The number of several bacterial indicators (faecal coliforms, Escherichia coli, enterococci and spores of sulfite-reducing clostridia) and bacteriophages (somatic coliphages, F-specific RNA bacteriophages and bacteriophages infecting Bacteroides fragilis) were determined in groundwater of aquifers in various geographical areas. Results show that the relative abundance, determined as percentages of positive detections, of the bacterial indicators and bacteriophages varies depending on the aquifer. CONCLUSIONS: A single bacterial indicator may not be enough to assess microbiological quality in certain aquifers. One bacterial indicator and a bacteriophage parameter provide more information than two bacterial indicators. SIGNIFICANCE AND IMPACT OF THE STUDY: Coliphages (CPH) provide different information from that provided by bacterial indicators on the microbial quality of groundwater in different geographical areas. Easy, fast and inexpensive methods for the detection of CPH are feasible in both industrialized and developing countries.

Stroke in rural Ecuador: a three-phase, door-to-door survey.

The authors carried out a three-phase door-to-door survey in Atahualpa, Ecuador to assess epidemiologic and pathogenetic mechanisms of stroke. They found 10 stroke patients among 1,568 individuals aged > or =15 years (crude prevalence, 638 per 100,000). There was only one incident case (incidence, 64 per 100,000). Six of the 10 patients had hypertensive arteriolopathy (five with ischemic and one with hemorrhagic stroke). Additional work is needed to increase knowledge on stroke in developing countries.

[Validation of a screening questionnaire for stroke detection in Spanish-speaking communities]. / Validación de un cuestionario para detección de ictus en poblaciones hispanoparlantes.

OBJECTIVE: To evaluate the accuracy of an screening questionnaire for stroke detection in speaking-speaking communities. PATIENTS AND METHODS: We performed a door-to-door survey in Atahualpa (a rural community in coastal Ecuador) using a modified version of the Spanish translation of the OMS questionnaire for stroke detection. Subjects suspected of having a stroke as well as a 2% sample of negative subjects were evaluated by neurologists to evaluate sensitivity, specificity, and predictive value of the questionnaire and that of each of its questions. RESULTS: We found 18 possible cases among 1,568 individuals around 15 years old. Of these, 10 were confirmed stroke patients and 8 were false-positive (crude stroke prevalence of 6.38 per 1,000). We did not find false-negative cases. Sensitivity of the questionnaire was 100%, specificity was 99.5%, positive predictive value was 0.55 and negative predictive value was 1. The accuracy of each question as well as the number of questions answered as affirmative were different between patients and false-positive cases. CONCLUSIONS: The current questionnaire is highly sensitive but its positive predictive value is poor. This causes problems in large-scale studies, as the detection of many false-positives may compromise its viability. We propose a modification of the questionnaire that will turn it more accurate.

Caracterización molecular de Klebsiella pneumoniae y Enterobacter cloacae productoras de ß-lactamasas de espectro extendido tipo SHV-5 en una unidad de cuidados intensivos neonatal de Lima / Molecular characterization of extended-spectrum type SHV-5 ß-Lactamases producing Klebsiella pneumoniae and Enterobacter cloacae in a neonatal intensive care unit in Lima

Objetivo: Determinar los mecanismos implicados en la transmisión y resistencia antimicrobiana de aislamientos hospitalarios de Klebsiella pneumoniae y Enterobacter cloacae. Materiales y métodos: Se determinó la diversidad genética de 10 aislamientos bacterianos provenientes de pacientes hospitalizados y muestras ambientales procedentes de una unidad de cuidados intensivos de neonatos de un hospital de Lima utilizando el patrón de banda de ADN ribosomal y plasmídico. Posteriormente, se caracterizó la resistencia antimicrobiana y sus principales factores utilizando electroforesis de punto isoeléctrico, Southern Blotting y PCR. Finalmente se evaluó la capacidad de transferencia de la resistencia mediante ensayos de conjugación bacteriana. Resultados: Todos los aislamientos de K. pneumoniae y E. cloacae presentaron el mismo perfil plasmídico. Los aislamientos de E. cloacae presentaron un mismo patrón genético, por el contrario se encontraron cuatro genotipos distintos de K. pneumoniae altamente relacionados. Todos los aislamientos produjeron ßlactamasa de especto extendido Tipo SHV-5 transferible a otras especies. Conclusiones: El estudio sugiere que la diseminación de estas bacterias en los neonatos pudo haber sido favorecida por un inadecuado manejo asistencial, una defectuosa conservación de leche para el consumo neonatal y el indiscriminado uso de antibióticos, el cual generó una activa transmisión de genes responsables de la resistencia antimicrobiana

Occurrence and densities of bacteriophages proposed as indicators and bacterial indicators in river waters from Europe and South America.

AIMS: To evaluate the feasibility of bacteriophages as a complementary tool for water quality assessment in surface waters from different parts of the globe. METHODS AND RESULTS: Faecal coliform bacteria, enterococci, spores of sulphite-reducing clostridia, somatic coliphages, F-specific RNA bacteriophages and bacteriophages infecting Bacteroides fragilis were determined by standardized methods in raw sewage and in 392 samples of river water from 22 sampling sites in 10 rivers in Argentina, Colombia, France and Spain, which represent very different climatic and socio-economic conditions. The results showed that the indicators studied maintained the same relative densities in the raw sewage from the different areas. Classifying the river water samples according to the content of faecal coliform bacteria, it can be observed that the relative densities of the different bacterial indicators and bacteriophages changed according to the concentration of faecal coliform bacteria. There was a relative increase in the densities of all groups of bacteriophages and sulphite-reducing clostridia with respect to faecal coliforms and enterococci in the samples with low counts of faecal coliform bacteria. CONCLUSIONS: The numbers of bacterial indicators and bacteriophages were similar in the different geographical areas studied. Once released in rivers, the persistence of the different micro-organisms differed significantly. Bacteriophages and spores of sulphite-reducing clostridia persisted longer than faecal coliforms and enterococci. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacteriophages in river water samples provide additional information to that provided by bacteria about the fate of faecal micro-organisms in river water. The easy, fast and cheap methods for phage determination are feasible both in industrialized and developing countries.

Analysis of herpes simplex virus 1 and 2 infection in women with high risk sexual behaviour in Mexico.

BACKGROUND: This paper describes the seroprevalence and risk factors of Herpes simplex virus (HSV) infection in a group of female prostitutes from Mexico City. METHODS: Women who consented to participate in the study voluntarily attended a sexually transmitted disease (STD) clinic during 1992. A standardized questionnaire was administered and a blood sample was obtained from each participant. Type-specific Western blot serology was performed to determine the serostatus of HSV-1 and HSV-2 for participants. Bivariate and multivariate analyses were applied to identify variables associated with an increased risk for HSV infection. RESULTS: Prevalences of infection among the 997 prostitutes studied were 93.9% for HSV-1 and 60.8% for HSV-2. Only 1.8% of the women were seronegative for both viruses. The only variable associated with HSV-1 seropositivity was crowding index. The following variables were associated with an increased risk for infection with HSV-2: age, level of education, working site, born outside Mexico City and increasing time as a prostitute. CONCLUSIONS: This is the first assessment of HSV infection in Mexico and may be useful for the development and application of control and preventive measures among the prostitute population at risk of acquiring and transmitting human immunodeficiency virus (HIV) and other STD.