Randomized placebo-controlled trial of oral tannin supplementation on COVID-19 symptoms, gut dysbiosis and cytokine response.

The clinical study aim was to investigate whether a tannin-based dietary supplementation could improve the efficacy of standard-of-care treatment of hospitalized COVID-19 patients by restoring gut microbiota function. Adverse events and immunomodulation post-tannin supplementation were also investigated. A total of 124 patients receiving standard-of-care treatment were randomized to oral tannin-based supplement or placebo for a total of 14 days. Longitudinal blood and stool samples were collected for cytokine and 16S rDNA microbiome profiling, and results were compared with 53 healthy controls. Although oral tannin supplementation did not result in clinical improvement or significant gut microbiome shifts after 14-days, a reduction in the inflammatory state was evident and significantly correlated with microbiota modulation. Among cytokines measured, MIP-1α was significantly decreased with tannin treatment (p = 0.03) where it correlated positively with IL-1ß and TNF- α, and negatively with stool Bifidobacterium abundance.

Clinical Course of COVID-19 and Cycle Threshold in Patients with Haematological Neoplasms.

The SARS-CoV-2 viral load in a respiratory sample can be inversely quantified using the cycle threshold (Ct), defined as the number of amplification cycles required to detect the viral genome in a quantitative PCR assay using reverse transcriptase (RT-qPCR). It may be classified as high (Ct < 25), intermediate (25-30) and low (Ct > 30). We describe the clinical course of 3 patients with haematological neoplasms who contracted COVID-19. None of them had been vaccinated. Firstly, a 22-year-old male with a refractory acute lymphoblastic leukaemia experienced an oligosymptomatic COVID-19 and had a Ct of 23 with an ascending curve. Another male, aged 23, had recently begun treatment for a promyelocytic leukaemia. He had a subacute course with high oxygen requirements. His Ct dropped from 28, when he only experienced fever, to 14.8, during the most critical period and on the edge of ventilatory support. Viral clearance was documented 126 days after the beginning of the symptoms. Finally, a 60-year-old male had received rituximab as maintenance therapy for a follicular lymphoma 3 months before contracting COVID-19. He had a fulminant course and required mechanical ventilation a few days later. We highlight the association between the course of CoViD-19 and the Ct. Viral shedding was longer than in immunocompetent hosts.

Development and evaluation of a low cost IgG ELISA test based in RBD protein for COVID-19.

Serology tests for SARS-CoV-2 have proven to be important tools to fight against the COVID-19 pandemic. These serological tests can be used in low-income and remote areas for patient contact tracing, epidemiologic studies and vaccine efficacy evaluations. In this study, we used a semi-stable mammalian episomal expression system to produce high quantities of the receptor-binding domain-RBD of SARS-CoV-2 in a simple and very economical way. The recombinant antigen was tested in an in-house IgG ELISA for COVID-19 with a panel of human sera. A performance comparison of this serology test with a commercial test based on the full-length spike protein showed 100% of concordance between tests. Thus, this serological test can be an attractive and inexpensive option in scenarios of limited resources to face the COVID-19 pandemic.

Natural tannin extracts supplementation for COVID-19 patients (TanCOVID): a structured summary of a study protocol for a randomized controlled trial.

OBJECTIVES: This research aims to study the efficacy of tannins co-supplementation on disease duration, severity and clinical symptoms, microbiota composition and inflammatory mediators in SARS-CoV2 patients. TRIAL DESIGN: This is a prospective, double-blind, randomized, placebo-controlled, parallel-group trial to evaluate the efficacy of the administration of the dietary supplement ARBOX, a molecular blend of quebracho and chestnut tannins extract and Vit B12, in patients affected by COVID-19. PARTICIPANTS: 18 years of age or older, admitted to Hospital de Clinicas Jose de San Martin, Buenos Aires University (Argentina), meeting the definition of "COVID-19 confirmed case" ( https://www.argentina.gob.ar/salud/coronavirus-COVID-19/definicion-de-caso ). Inclusion Criteria Participants are eligible to be included in the study if the following criteria apply: 1. Any gender 2. ≥18 years old 3. Informed consent for participation in the study 4. Virological diagnosis of SARS-CoV-2 infection (real-time PCR) Exclusion Criteria Participants are excluded from the study if any of the following criteria apply: 1. Pregnant and lactating patients 2. Patients who cannot take oral therapy (with severe cognitive decline, assisted ventilation, or impaired consciousness) 3. Hypersensitivity to polyphenols 4. Patients already in ICU or requiring mechanical ventilation 5. Patients already enrolled in other clinical trials 6. Decline of consent INTERVENTION AND COMPARATOR: Experimental: TREATED ARM Participants will receive a supply of 28 -- 390 mg ARBOX capsules for 14 days. Patients will be supplemented with 2 capsules of ARBOX per day. Placebo Comparator: CONTROL ARM Participants will receive placebo supply for 14 days. The placebo will be administered with the identical dose as described for the test product. All trial participants will receive standard therapy, which includes: Antipyretics or Lopinavir / Ritonavir, Azithromycin and Hydroxychloroquine, as appropriate (treatment currently recommended by the department of Infectious Diseases of the Hospital de Clínicas that could undergo to modifications). In addition, if necessary: supplemental O2, non-invasive ventilation, antibiotic therapy. MAIN OUTCOMES: Primary Outcome Measures: Time to hospital discharge, defined as the time from first dose of ARBOX to hospital discharge [ Time Frame: Throughout the Study (Day 0 to Day 28) ] Secondary Outcome Measures: 28-day all-cause mortality [ Time Frame: Throughout the Study (Day 0 to Day 28) ]-proportion Invasive ventilation on day 28 [ Time Frame: Throughout the Study (Day 0 to Day 28) ]-proportion Level of inflammation parameters and cytokines [ Time Frame: day 1-14 ] -mean difference Difference in fecal intestinal microbiota composition and intestinal permeability [ Time Frame: day 1-14 ] Negativization of COVID-PCR at day 14 [ Time Frame: day 14 ]-proportion RANDOMIZATION: Potential study participants were screened for eligibility 24 hours prior to study randomization. Patients were randomly assigned via computer-generated random numbering (1:1) to receive standard treatment coupled with tannin or standard treatment plus placebo (control group). BLINDING (MASKING): Study personnel and participants are blinded to the treatment allocation, as both ARBOX and placebo were packed in identical containers. Thus, all the used capsules had identical appearance. NUMBERS TO BE RANDOMIZED (SAMPLE SIZE): Considering an alpha error of 5%, a power of 80% a sample size of 70 patients per branch was estimated. 140 patients in total. TRIAL STATUS: The protocol version is number V2, dated May 23, 2020. The first patient, first visit was on June 12, 2020; the recruitment end date was October 6, 2020. The protocol was not submitted earlier because the enrollment of some patients took place after the closure of the recruitment on the clinicaltrials platform. In fact, due to the epidemiological conditions, due to the decrease of the cases in Argentina during the summer period, the recruitment stopped t before reaching the number of 140 patients (as indicated in the webpage). However, since there was a new increase in cases, the enrolment was resumed in order to reach the number of patients initially planned in the protocol. The final participant was recruited on February 14, 2021. TRIAL REGISTRATION: ClinicalTrials.gov, number: NCT04403646 , registered on May 27th, 2020. FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Incorporation of the rapid HIV test in a sexually-transmitted disease clinic in Buenos Aires: Dramatic increase in the frequency of HIV diagnosis.

Improving access to diagnosis constitutes a key step in the control of the Human immunodeficiency virus (HIV)/AIDS epidemic. Rapid testing is increasingly gaining interest as a powerful diagnostic tool to achieve this goal. The purpose of this study was to implement the rapid HIV test (RHT) in a clinical setting in order to evaluate its effectiveness in increasing HIV diagnosis and patient linkage to the healthcare system. The RHT was offered to all patients attending a sexually-transmitted disease clinic in the City of Buenos Aires between March and December 2015. A total of 593 RHT were performed. The implementation of the RHT yielded an increase in frequency of diagnosis from 6.9% to 31.4% (p<0.001). The first steps of the care cascade showed high retention rates around 90%. RHT yielded an HIV prevalence of 6.3% (95% CI: 4.2-8.5) in this population. HIV prevalence tended to be higher in individuals with no previous HIV testing (p=0.09). Linkage to the healthcare system was associated with a higher probability of having been tested for HIV (p=0.008). The incorporation of the RHT resulted in a high retention of patients and an increase in both frequency of diagnosis and results reception when compared to the classic methodology.

Rectal Lymphogranuloma Venereum, Buenos Aires, Argentina.

Among 34 men with proctitis in Buenos Aires, Argentina, 16 (47%) had Chlamydia trachomatis infection, 11 (68.8%) of which were biovar lymphogranuloma venereum. The outbreak was probably local, as in Europe. In Argentina, lymphogranuloma venereum should be a suspected cause of proctitis in HIV-infected men who have had unprotected anal sex with men.

Comprehensive global genome dynamics of Chlamydia trachomatis show ancient diversification followed by contemporary mixing and recent lineage expansion.

Chlamydia trachomatis is the world's most prevalent bacterial sexually transmitted infection and leading infectious cause of blindness, yet it is one of the least understood human pathogens, in part due to the difficulties of in vitro culturing and the lack of available tools for genetic manipulation. Genome sequencing has reinvigorated this field, shedding light on the contemporary history of this pathogen. Here, we analyze 563 full genomes, 455 of which are novel, to show that the history of the species comprises two phases, and conclude that the currently circulating lineages are the result of evolution in different genomic ecotypes. Temporal analysis indicates these lineages have recently expanded in the space of thousands of years, rather than the millions of years as previously thought, a finding that dramatically changes our understanding of this pathogen's history. Finally, at a time when almost every pathogen is becoming increasingly resistant to antimicrobials, we show that there is no evidence of circulating genomic resistance in C. trachomatis.

Origin of modern syphilis and emergence of a pandemic Treponema pallidum cluster.

The abrupt onslaught of the syphilis pandemic that started in the late fifteenth century established this devastating infectious disease as one of the most feared in human history1. Surprisingly, despite the availability of effective antibiotic treatment since the mid-twentieth century, this bacterial infection, which is caused by Treponema pallidum subsp. pallidum (TPA), has been re-emerging globally in the last few decades with an estimated 10.6 million cases in 2008 (ref. 2). Although resistance to penicillin has not yet been identified, an increasing number of strains fail to respond to the second-line antibiotic azithromycin3. Little is known about the genetic patterns in current infections or the evolutionary origins of the disease due to the low quantities of treponemal DNA in clinical samples and difficulties in cultivating the pathogen4. Here, we used DNA capture and whole-genome sequencing to successfully interrogate genome-wide variation from syphilis patient specimens, combined with laboratory samples of TPA and two other subspecies. Phylogenetic comparisons based on the sequenced genomes indicate that the TPA strains examined share a common ancestor after the fifteenth century, within the early modern era. Moreover, most contemporary strains are azithromycin-resistant and are members of a globally dominant cluster, named here as SS14-Ω. The cluster diversified from a common ancestor in the mid-twentieth century subsequent to the discovery of antibiotics. Its recent phylogenetic divergence and global presence point to the emergence of a pandemic strain cluster.

Optimization of Trichomonas vaginalis Diagnosis during Pregnancy at a University Hospital, Argentina.

The aim of this study was to evaluate different methods for Trichomonas vaginalis diagnosis during pregnancy in order to prevent maternal and perinatal complications. A total of 386 vaginal exudates from pregnant women were analyzed. T. vaginalis was investigated by 3 types of microscopic examinations direct wet mount with physiologic saline solution, prolonged May-Grunwald Giemsa (MGG) staining, and wet mount with sodium-acetate-formalin (SAF)/methylene blue method. PCR for 18S rRNA gene as well as culture in liquid medium were performed. The sensitivity and specificity of the microscopic examinations were evaluated considering the culture media positivity or the PCR techniques as gold standard. The frequency of T. vaginalis infection was 6.2% by culture and/or PCR, 5.2% by PCR, 4.7% by culture, 3.1% by SAF/methylene blue method and 2.8% by direct wet smear and prolonged MGG staining. The sensitivities were 83.3%, 75.0%, 50.0%, and 45.8% for PCR, culture, SAF/methylene blue method, and direct wet smear-prolonged MGG staining, respectively. The specificity was 100% for all the assessed methods. Microscopic examinations showed low sensitivity, mainly in asymptomatic pregnant patients. It is necessary to improve the detection of T. vaginalis using combined methods providing higher sensitivity, such as culture and PCR, mainly in asymptomatic pregnant patients, in order to prevent maternal and perinatal complications.

Prevalencia de la infección por Chlamydia trachomatis y factores de riesgo de infecciones transmisibles sexualmente en estudiantes universitarios / Prevalence of Chlamydia trachomatis infection and factors with the risk of acquiring sexually transmitted infections in college students

La infección genital por Chlamydia trachomatis es considerada en la actualidad una de las causas más frecuentes de infecciones transmisibles sexualmente (ITS) a nivel mundial y afecta principalmente al grupo de jóvenes menores de 25 años. El objetivo de este estudio fue determinar la prevalencia de la infección por C. trachomatis en alumnos ingresantes a la Universidad Nacional del Sur (Bahía Blanca, Argentina) y evaluar los factores de riesgo para la adquisición de ITS. Participaron en el estudio 204 jóvenes de edad media de 19 años, que remitieron una muestra de orina de primera micción y respondieron a una encuesta anónima. La investigación de C. trachomatis se realizó sobre 114 muestras válidas mediante una técnica de amplificación génica, cuyo blanco molecular es el gen ompA. Se detectaron 4 casos de infección por C. trachomatis, lo que implicó una prevalencia del 3,5 %. Los factores de riesgo que demostraron estar asociados con la adquisición de esta ITS fueron un historial de 7 o más parejas desde el comienzo de las relaciones sexuales y el contacto con una nueva pareja sexual en los últimos 4 meses. La prevalencia de infección por C. trachomatis reflejó una moderada circulación de este microorganismo en la población estudiada. Si bien algunos aspectos revelados en las encuestas sugieren una población de bajo riesgo para la adquisición de ITS en general, otros datos evidencian lo contrario y alertan sobre la necesidad de incrementar la vigilancia y desarrollar acciones de concienciación y prevención en esta población.

Chlamydia trachomatis genital infection is nowadays considered one of the most frequent causes of sexually transmitted infections (STI) in the world, mainly affecting the group of young people under 25 years old. The aim of this study was to determine the prevalence of C. trachomatis infection in newly admitted students to Universidad Nacional del Sur, Bahía Blanca, Argentina, and to evaluate the risk factors to acquire STI. For that purpose, 204 young college students with a mean age of 19 were involved in this study. Each participant delivered a sample of first-void urine and completed a questionnaire which was then submitted anonymously. The research for C. trachomatis was done on 114 valid samples through a technique of DNA amplification, whose molecular target was the gene ompA. Four cases of infection by C. trachomatis were detected with a prevalence of 3.5 %. The risks factors associated to the infection were a history of 7 or more partners since the start of sexual activity and contact with a new sexual partner in the last 4 months. The prevalence of such infection reflects a moderate circulation of this microorganism in the studied population. This fact, along with some aspects shown by the questionnaire results, would characterize a population having a low risk profile for acquiring STIs. However, some other information obtained from the questionnaires gave some opposite evidence, which would alert us on the need of keeping watch, raising awareness and implementing preventive actions in this population.

Prevalencia de la infección por Chlamydia trachomatis y factores de riesgo de infecciones transmisibles sexualmente en estudiantes universitarios / Prevalence of Chlamydia trachomatis infection and factors with the risk of acquiring sexually transmitted infections in college students

La infección genital por Chlamydia trachomatis es considerada en la actualidad una de las causas más frecuentes de infecciones transmisibles sexualmente (ITS) a nivel mundial y afecta principalmente al grupo de jóvenes menores de 25 años. El objetivo de este estudio fue determinar la prevalencia de la infección por C. trachomatis en alumnos ingresantes a la Universidad Nacional del Sur (Bahía Blanca, Argentina) y evaluar los factores de riesgo para la adquisición de ITS. Participaron en el estudio 204 jóvenes de edad media de 19 años, que remitieron una muestra de orina de primera micción y respondieron a una encuesta anónima. La investigación de C. trachomatis se realizó sobre 114 muestras válidas mediante una técnica de amplificación génica, cuyo blanco molecular es el gen ompA. Se detectaron 4 casos de infección por C. trachomatis, lo que implicó una prevalencia del 3,5 %. Los factores de riesgo que demostraron estar asociados con la adquisición de esta ITS fueron un historial de 7 o más parejas desde el comienzo de las relaciones sexuales y el contacto con una nueva pareja sexual en los últimos 4 meses. La prevalencia de infección por C. trachomatis reflejó una moderada circulación de este microorganismo en la población estudiada. Si bien algunos aspectos revelados en las encuestas sugieren una población de bajo riesgo para la adquisición de ITS en general, otros datos evidencian lo contrario y alertan sobre la necesidad de incrementar la vigilancia y desarrollar acciones de concienciación y prevención en esta población.(AU)

Chlamydia trachomatis genital infection is nowadays considered one of the most frequent causes of sexually transmitted infections (STI) in the world, mainly affecting the group of young people under 25 years old. The aim of this study was to determine the prevalence of C. trachomatis infection in newly admitted students to Universidad Nacional del Sur, Bahía Blanca, Argentina, and to evaluate the risk factors to acquire STI. For that purpose, 204 young college students with a mean age of 19 were involved in this study. Each participant delivered a sample of first-void urine and completed a questionnaire which was then submitted anonymously. The research for C. trachomatis was done on 114 valid samples through a technique of DNA amplification, whose molecular target was the gene ompA. Four cases of infection by C. trachomatis were detected with a prevalence of 3.5 %. The risks factors associated to the infection were a history of 7 or more partners since the start of sexual activity and contact with a new sexual partner in the last 4 months. The prevalence of such infection reflects a moderate circulation of this microorganism in the studied population. This fact, along with some aspects shown by the questionnaire results, would characterize a population having a low risk profile for acquiring STIs. However, some other information obtained from the questionnaires gave some opposite evidence, which would alert us on the need of keeping watch, raising awareness and implementing preventive actions in this population.(AU)

Genetic diversity of Chlamydia among captive birds from central Argentina.

To study the occurrence of Chlamydia spp. and their genetic diversity, we analysed 793 cloacal swabs from 12 avian orders, including 76 genera, obtained from 80 species of asymptomatic wild and captive birds that were examined with conventional nested polymerase chain reaction and quantitative polymerase chain reaction. Chlamydia spp. were not detected in wild birds; however, four species (Chlamydia psittaci, Chlamydia pecorum, Chlamydia pneumoniae and Chlamydia gallinacea) were identified among captive birds (Passeriformes, n = 20; Psittaciformes, n = 15; Rheiformes, n = 8; Falconiformes n = 2; Piciformes n = 2; Anseriformes n = 1; Galliformes n = 1; Strigiformes n = 1). Two pathogens (C. pneumoniae and C. pecorum) were identified simultaneously in samples obtained from captive birds. Based on nucleotide-sequence variations of the ompA gene, three C. psittaci-positive samples detected were grouped into a cluster with the genotype WC derived from mammalian hosts. A single positive sample was phylogenetically related to a new strain of C. gallinacea. This report contributes to our increasing understanding of the abundance of Chlamydia in the animal kingdom.

HIV and other sexually transmitted infections among men who have sex with men recruited by RDS in Buenos Aires, Argentina: high HIV and HPV infection.

BACKGROUND: The aim of this study was to estimate the prevalence of HIV and other STIs, among MSM from Buenos Aires (2007-2009). METHODS: Responding Driven Sampling was used for recruitment of MSM. Participants completed a structured web-based survey and provided biological samples. RESULTS: A total of 496 MSM were studied for HIV, HBV, HCV, and T. pallidum infections. Chlamydia and HPV diagnoses were only performed in 98 and 109 participants, respectively. Prevalence of HIV was 17.3%, HBV 22.9%, HCV 7.5%, T. pallidum 20.5%, HPV 83.5%, and C. trachomatis 1.7%. In the year prior to the evaluation, 71% of the participants had had sex with men and/or trans and women (MMW) while 29% had not had sex with women (MM). Comparing MM to MMW, prevalence of HIV (30.7% vs. 11.9%, p<0.001), HBV (36.4% vs. 17.8%, p<0.001), T. pallidum (32.1% vs. 15.7%, p<0.001), and HPV (88.3% vs. 70.4%, p = 0.039) were significantly higher among MM, whereas no significant differences were found for HCV and C. trachomatis. The MM group had also significantly higher HIV incidence (5.60 vs. 4.28 per 100 persons-year, p = 0.032). HPV genotypes 16, 6, and 11 were the most frequently found; 40.7% of the MSM had more than one genotype and one high risk genotype was detected in 43.6% of participants. CONCLUSIONS: Both MM and MMW are at high risk of infection for HIV and other STIs. Rates of HIV, HBV, T. pallidum and HPV infections are higher in the MM group.

First report on sexually transmitted infections among trans (male to female transvestites, transsexuals, or transgender) and male sex workers in Argentina: high HIV, HPV, HBV, and syphilis prevalence.

OBJECTIVES: Due to the scarce data on the prevalence of sexually transmitted infections (STIs) among male-to-female trans-sex workers (TSW) and male sex workers (MSW) in Argentina, the present study aimed to estimate the incidence of human immunodeficiency virus (HIV), and the prevalence of HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), and Treponema pallidum. Human papillomavirus (HPV) and Chlamydia trachomatis infections were tested among TSW. METHODS: Two hundred and seventy-three TSW and 114 MSW were recruited by nongovernmental organizations. HIV incidence was estimated by STARHS (serologic testing algorithm for recent HIV seroconversion). HPV and C. trachomatis infections were tested in anal cells from TSW. RESULTS: TSW showed significantly higher prevalences of HIV (34.1 vs. 11.4%), HBV (40.2 vs. 22.0%), and T. pallidum (50.4 vs. 20.4%) than MSW. TSW tested positive for HPV in 111/114 cases and for C. trachomatis in 4/80 cases. Investigation of HBV, HCV, HIV, and T. pallidum co-infections showed that 72% of TSW and 39% of MSW had at least one STI. T. pallidum was the most frequent mono-infection. The estimated HIV incidence was 10.7 per 100 person-years (95% confidence interval (CI) 3.8-17.7) for TSW and 2.3 per 100 person-years (95% CI 0-6.7) for MSW. CONCLUSIONS: The high prevalence of STIs and the high incidence of HIV demonstrate the great vulnerability of these high-risk populations and indicate the urgent need for preventive strategies on intervention and facilitation of access to healthcare programs.

Viruses and atypical bacteria associated with asthma exacerbations in hospitalized children.

UNLABELLED: OBJECTIVES AND WORKING HYPOTHESIS: To evaluate the prevalence of respiratory viruses Mycoplasma pneumoniae and Chlamydophila pneumoniae and gain insight into their seasonal circulation pattern in children with acute asthma exacerbations in a temperate southern hemisphere region. STUDY DESIGN: Patients hospitalized between 3 months and 16 years of age were included in a 1-year prospective, observational, cross-sectional study. Respiratory secretions were collected and the presence of different viruses and atypical bacteria analyzed by immunofluorescence and polymerase chain reaction. RESULTS: Two hundred nine patients (118 females) aged (mean +/- SD) 4.4 +/- 4 years were included. A potential causative agent was detected in 78% of the patients. The most frequently detected viruses were respiratory syncytial virus (HRSV) (n = 85; 40%) and rhinovirus (HRV) (n = 52; 24.5%); M. pneumoniae and C. pneumoniae were detected in 4.5% and 2% of the cases, respectively. Patients with HRSV (vs. HRV) were hospitalized for a longer time (6.7 vs. 5.2 days, P = 0.012), required more days of oxygen supply (5.1 vs. 3.4, P = 0.005), had a longer duration of the exacerbation before hospitalization (3.6 vs. 1.9 days, P = 0.001) and were younger (3.7 vs. 5.1 years, P = 0.012). Three peaks of admissions were observed. A first peak (early autumn) caused by HRV, a second peak (winter) caused mainly by HRSV and a third one (spring), caused by HRSV, an increase in HMPV together with a second outbreak of HRV. CONCLUSIONS: Children with an acute asthma exacerbation presented a high prevalence of respiratory viruses. Most hospitalizations corresponded to seasonal increases in prevalence of HRV and HRSV.

Trends of syphilis in Posadas city (Misiones State, Argentina), 1997-2000 / Incidência de sífilis na cidade de Posadas (estado de Misiones, Argentina), 1997-2000

Objetivos: O estado de Misiones está situado no noroeste argentino, nas fronteiras oeste e norte com o Brasil e a leste do Paraguai. Este foi o interesse para estabelecer a evolução da sífilis na cidade de Posadas (300.000 habitantes), capital do estado de Misiones, desde 1997 até 2000. Métodos: A sífilis foi analisada por meio da avaliação epidemiológica, clínica e confirmação laboratorial (VDRL e FTA-ABS). Todas as mulheres grávidas no momento da evolução foram consultadas no hospital Madariaga, durante o período de abril a junho, de 1997 até 2000 (n = 4700), as quais foram incluídas nas análises. Resultados: A freqüência da sífilis em mulheres grávidas atendidas em hospital público foi de 2,1 por cento (1997), 2,6 por cento (1998), 4,6 por cento (1999) e 3,7 por cento (2000). A faixa etária de maior vulnerabilidade foi de 15 a 19 anos. A distribuição geográfica de casos originados de quatro grupos isolados em 1997 expandiu-se para uma grande ocorrência em todas as regiões de baixo nível de vida socioeconômico (30 por cento do total da população). A sífilis congênita chegou a uma média de 10,8 casos por 1000 crianças nascidas vivas nos últimos anos. Conclusão: A cidade de Posadas teve um aumento de sífilis em mulheres grávidas de 1997 até 1999. Esta situação endêmica indica que o programa convencional STD-Aids teve um efeito mínimo ou nulo sobre a prática do sexo, principalmente em grupos de adolescentes. Um programa de intervenção do alvo geográfico (visita casa por casa) direcionado para prover controle pré-natal como prioridade teve início em 1999. Uma estabilização da sífilis em mulheres grávidas foi demonstrada em 2000, mas a incidência é ainda demasiadamente alta. Torna-se necessária a discussão de um programa de extensão regional que inclua a população binacional das grandes áreas povoadas