Exploring hepatitis E virus seroprevalence and associated risk factors among the human population in Tandil, Buenos Aires, Argentina.

Background: Hepatitis E virus (HEV) infection is a common cause of acute clinical hepatitis worldwide and is emerging as a disease in Argentina. It is primarily transmitted through contaminated water and food, following the fecal-oral route. Furthermore, is a zoonotic disease with swine as the primary reservoir. Prevalence of HEV infection in humans in several regions of Argentina remains unknown. Objectives: (i) Determine the seroprevalence of HEV among the human population in Tandil, Buenos Aires, Argentina; (ii) Evaluate its association with demographic, socioeconomic and other risk exposures variables, and (iii) Describe and analyze spatial patterns related to HEV infection. Methods: From August 2020 to July 2021, serum samples were collected from 969 individuals aged 1-80 years. Seroprevalence and 95% Confidence Interval was determined. To assess the factors associated with the presence of anti-HEV antibodies, associations between the variables and seropositivity were evaluated through bivariate and multivariate analysis. Spatial scanning for clusters of positivity was carried out. Factors associated with these clusters were also assessed. Results: Anti-HEV antibodies were detected in 4.64% (IC 95% 3.27-6.02) of samples. Dark urine was associated with seropositivity (p = 0.02). Seropositivity was linked with the presence of natural water courses near their households (p = 0.02); the age (p = 0.04); and previous travel to Europe (p = 0.04). A spatial cluster of low rates of HEV seropositivity was detected, with greater distance of the households to water courses associated to the cluster, and male sex inversely associated to it. Discussion and conclusion: This study is the first study to investigate the prevalence of HEV in the population from Tandil, Buenos Aires, Argentina. Considering HEV infection in the differential diagnosis in individuals presenting acute hepatitis is highlighted. The incorporation of HEV testing into blood screening policies should be mandatory. Factors related to the infection and spatial patterns of high and low risk were determined, and should be considered when implementing specific preventive measures.

Epidemiology of Leptospira spp. infection in a beef cattle area of Argentina.

Leptospirosis is an infectious disease caused by pathogenic Leptospira that affect humans and animals. This disease is complex and non-eradicable in nature. Therefore, the understanding of it is epidemiology in different environments is crucial to implement prevention and control measures. The prevalence of Leptospira infection in beef cattle farms is affected by multiple environmental, management and individual factors. In this study, a cross-sectional serological survey was carried on to estimate the prevalence of Leptospira antibodies in beef cattle in Tandil and Ayacucho Departments (Buenos Aires Province) and to identify risk factors and spatial clusters associated with seropositivity. Using a probabilistic two-stage sampling, 25 farms and 15 animals per farm were selected. The Microagglutination Test was used to analize all serum samples. Bivariate and multivariate analyses were performed. Seventy-three out of 375 cows were seropositive, representing a positivity rate of 19.47% (95% CI: 10.51-28.42), with Sejroe and Pomona being the most reactive serogroups: 9.33% (95% CI: 6.26-12.41) and 8.27% (95% CI: 5.35-11.19), respectively. The prevalence in Ayacucho was 23.11% (95% CI: 10.05-36.17), and in Tandil, 14% (95% CI: 3.25-24.75). The animals from Ayacucho presented 2.01 (1.16-3.49) more chances of being positive compared with those from Tandil (p < 0.01). After the Generalized Linear Mixed Model (GLMM) with random effect of farm-level risk, the presence of lagoons (OR: 7.32, 95% CI: 1.68-31.8, p < 0.05) and undulating terrain (OR: 0.24, 95% CI: 0.07-0.74, p < 0.05) were associated with bovine leptospirosis. Four spatial clusters with higher rates of seropositivity were detected. A new GLMM was performed with the significant variables detected in the first GLMM and a new variable, "being inside the spatial cluster," being the only one that remained significant (OR: 9.58, 95% CI: 3.39-27.08, p < 0.0001). The animals inside the clusters belonged to farms with a greater presence of creeks (OR: 9.03, 95% CI: 3.37-24.18, p < 0.0001), higher accumulated rainfall (OR: 1.01, 95% CI: 1-1.01, p < 0.0001) and less undulating terrain (OR: 0.18, 95% CI: 0.10-0.35, p < 0.0001). We conclude that Leptospira is seroprevalent in beef cattle in Tandil and Ayacucho Departments, especially in the latter, where the largest cattle farms are located. Prevalence of seropositivity animals was associated with selected environmental risk factors.

Calidad microbiològica de la carne picada y detección de patógenos en muestras ambientales de carnicerías de la ciudad de Tandil, provincia de Buenos Aires,Argentina / Microbiological quality of fresh ground beef and detection of pathogens in environmental samples taken from butcher shops in the city of Tandil, Buenos Aires Province, Argentina

Resumen Este estudio evaluó las condiciones higiénico-sanitarias de carnicerías de la ciudadde Tandil (provincia de Buenos Aires) mediante una estimación del riesgo basada en encuestasdirigidas a revisar las buenas prácticas de manufactura y de higiene de los establecimientos. Seutilizó una escala de 1 a 100 para clasificar a los establecimientos en las categorías de riesgoalto (0-40), riesgo moderado (41-70) y riesgo bajo (71-100). A su vez, se evaluó la presencia deSalmonella spp., Staphylococcus aureus, Escherichia coli productor de toxina Shiga (STEC) encarne bovina picada y en muestras ambientales como mesada, cuchilla, picadora y manos delcarnicero. Las muestras se tomaron una sola vez e inmediatamente se refrigeraron y transpor-taron al laboratorio para su análisis. En el período de estudio todas las carnicerías (100) fueronclasificadas como de «riesgo bajo¼ y con buenas condiciones higiénico-sanitarias. No obstante,el 75% de las muestras de carne picada no cumplió con al menos uno de los criterios microbiológicos establecidos en el Artículo 255 del Código Alimentario Argentino. Se sugiere estableceruna estrategia tendiente a identificar los desvíos e implementar un plan de mejoras continuasen las carnicerías de la ciudad de Tandil.

Abstract The aim of this work was to evaluate the hygienic-sanitary conditions of butcher shops in Tandil, Buenos Aires Province, by estimating the risk based on good manufacturing and hygiene practices, through surveys of the establishments. The analysis was performed using a scale of 1-100, and classifying them as high risk (0-40), moderate risk (41-70) or low risk (71-100). The presence of Salmonella spp., Staphylococcus aureus and Shiga toxin-producing Escherichia coli (STEC) from both, ground beef and environmental samples such as countertop, cleaver, mincer and butcher's hands, taken at butcher shops was also evaluated. Sampling was performed only once and immediately refrigerated and transported to the laboratory for analysis. All butcher shops evaluated (100) were classified as "low risk'' with good hygienic-sanitary conditions. However, 75% of the ground beef samples analyzed did not meet at least one of the microbiological criteria established in the Código Alimentario Argentino [Argentine Food Code], article 255. We propose to establish a strategy to identify deviations and implement a plan for continuous improvement in butcher shops of Tandil city.

[Microbiological quality of fresh ground beef and detection of pathogens in environmental samples taken from butcher shops in the city of Tandil, Buenos Aires Province, Argentina]. / Calidad microbiológica de la carne picada y detección de patógenos en muestras ambientales de carnicerías de la ciudad de Tandil, provincia de Buenos Aires, Argentina.

The aim of this work was to evaluate the hygienic-sanitary conditions of butcher shops in Tandil, Buenos Aires Province, by estimating the risk based on good manufacturing and hygiene practices, through surveys of the establishments. The analysis was performed using a scale of 1-100, and classifying them as high risk (0-40), moderate risk (41-70) or low risk (71-100). The presence of Salmonella spp., Staphylococcus aureus and Shiga toxin-producing Escherichia coli (STEC) from both, ground beef and environmental samples such as countertop, cleaver, mincer and butcher's hands, taken at butcher shops was also evaluated. Sampling was performed only once and immediately refrigerated and transported to the laboratory for analysis. All butcher shops evaluated (100) were classified as "low risk" with good hygienic-sanitary conditions. However, 75% of the ground beef samples analyzed did not meet at least one of the microbiological criteria established in the Código Alimentario Argentino [Argentine Food Code], article 255. We propose to establish a strategy to identify deviations and implement a plan for continuous improvement in butcher shops of Tandil city.

[Detection of serovars of Salmonella in artificially reared calves in Mar y Sierras Dairy Basin, Argentina]. / Detección de serovares de Salmonella en terneros de crianza artificial de la región lechera Mar y Sierras, Argentina.

Salmonellosis in calves is a bacterial disease that affects their digestive tract causing diarrhea. A cross-sectional epidemiological study was carried out with the aim of studying the prevalence of various serovars of Salmonella in calves and their relationship with diarrhea signs. The study was conducted in Mar and Sierras Dairy Basin located in Buenos Aires province, Argentina. Seven hundred and twenty six calves both with diarrhea signs or not were sampled by rectal mucosa swab in 50 dairy farms during the rearing period. Isolates identified as Salmonella spp. were classified using polyvalent and monovalent antisera against somatic, flagellar and capsule antigens (Vi). Salmonella spp. was found in 36% of the farms and serotypes were: S. Mbandaka, S. Anatum, S. Typhimurium, S. Dublin, S. Montevideo, S. Meleagridis, S. Newport, S. Seftemberg, S. subesp. 16,7:z1, S. Infantis, S. Give. A percentage of 5.5% calves was positive and calves showing diarrheal signs were 5.9 times more likely to be infected with Salmonella spp. than those having no signs. The age of positive calves ranged from the first day of life to 53; the second day being the most frequent time. In conclusion, 11 Salmonella serovars were detected in one out of 3dairy farms in Mar and Sierras Dairy Basin, and not only were these serovars associated with diarrhea signs including the presence of mucus in feces, but they were also more prevalent among calves aged up to 21 days.

A novel association of BoLA DRB3 alleles in BLV infected cattle with different proviral loads / Uma nova associação de alelos de BoLA DRB3 em bovinos infectados com BLV com diferentes cargas provirais

Bovine leukemia virus (BLV) is associated with the most common neoplastic disease of cattle. BLV has a silent dissemination in the herd due to infected cell exchange, thus the concentration of BLV-infected cells in blood should play a major role in the success of viral transmission. Genes from Bovine leukocyte antigen (BoLA), the MHC system of cattle, are associated with genetic resistance and susceptibility to a wide range of diseases, and also with production traits. Some BoLA DRB3.2 allele polymorphisms in Holstein cattle have been associated with resistance or susceptibility to BLV-disease development, or with proviral load (PVL). This investigation studied 107 BLV-infected Argentinean Holstein dairy cows, all of them belonging to one herd. PVL was analysed by qPCR and animals were classified as high proviral load (HPVL, N = 88) and low proviral load (LPVL, N = 19), and BoLA DRB3.2 alleles were genotyped. Alleles BoLA DRB3.2*1501 and *1201 were significantly associated with HPVL (p = 0.0230 and p = 0.0111 respectively), while allele BoLA DRB3.2*0201 was significantly associated with LPVL (p = 0.0030). The present study aims at contributing to the knowledge of the association between BoLA polymorphism and development of a BLV infection profile. Genes that best explain the PVL in this population resulted BoLA DRB3.2*0201 (as a protection factor) and *1501 (as a risk factor). Allelic differences may play an important role in the development of effective immune responses. A better understanding of how BoLA polymorphism contributes to these responses and the establishment of a BLV status is desirable to schedule and evaluate control measures.(AU)

O vírus da leucemia bovina (BLV) está associado à doença neoplásica mais comum do gado bovino. O BLV tem uma disseminação silenciosa no rebanho devido à troca de células infectadas, assim, a concentração de células BLV infectadas no sangue deve desempenhar um papel importante no sucesso da transmissão viral. Os genes do antígeno leucocitário bovino (BoLA), sistema MHC do gado bovino, estão associados à resistência genética e à susceptibilidade a uma ampla gama de doenças, bem como às características da produção. Alguns polimorfismos de alelos de BoLA DRB3.2 em bovinos Holstein têm sido associados à resistência ou susceptibilidade ao desenvolvimento da doença BLV, ou com carga proviral (PVL). Esta investigação avaliou 107 vacas leiteiras da raça Holstein argentina infectadas com BLV e pertencentes a um único rebanho. A PVL foi analisada por qPCR, os animais foram classificados em alta carga proviral (HPVL, N = 88) e baixa carga proviral (LPVL, N = 19), e os alelos BoLA DRB3.2 foram genotipados. Os alelos BoLA DRB3.2*1501 e *1201 estavam significativamente relacionados à HPVL (p = 0,0230 e p = 0,0111, respectivamente), enquanto o alelo BoLA DRB3.2*0201, à LPVL (p = 0,0030). O objetivo deste estudo é contribuir para o conhecimento da associação entre o polimorfismo de BoLA e o desenvolvimento de infecção por BLV. Os genes que melhor explicam a PVL na população analisada resultaram em BoLA DRB3.2*0201 (como fator de proteção) e *1501 (como fator de risco). As diferenças alélicas podem desempenhar um papel importante no desenvolvimento de respostas imunitárias eficazes. Uma melhor compreensão de como o polimorfismo BoLA contribui para estas respostas e o estabelecimento de um estado BLV é desejável para agendar e avaliar as medidas de controle.(AU)

Association of TNF-α gene promoter region polymorphisms in bovine leukemia virus (BLV)-infected cattle with different proviral loads.

Tumor necrosis factor alpha (TNF-α) is a pleiotropic cytokine involved in the immune response against viral and other infections. Its expression levels are affected by a polymorphism in the promoter region of the gene. Bovine leukemia virus is a retrovirus that infects cattle and develops two different infection profiles in the host. One profile is characterized by a high number of proviral copies integrated into the host genome and a strong immune response against the virus, while the most relevant property of the other profile is that the number of copies integrated into the host genome is almost undetectable and the immune response is very weak. We selected a population of cattle sufficiently large for statistical analysis and classified them according to whether they had a high or low proviral load (HPL or LPL). Polymorphisms in the promoter region were identified by PCR-RFLP. The results indicated that, in the HPL group, the three possible genotypes were normally distributed and that, in the LPL group, there was a significant association between the proviral load and a low frequency of the G/G genotype at position -824.

Determinación temprana del sexo fetal en plasma materno mediante PCR en tiempo real / Early fetal sex determination in maternal plasma by real-time PCR / Determinação precoce do sexo fetal em plasma materno por PCR em tempo real

El análisis de ADN fetal libre en plasma ,materno permite estudiar material genético del feto sin realizar procedimientos invasivos sobre el embarazo. La identificación del sexo fetal mediante la detección de ADN del cromosoma masculino Y, en el plasma de mujeres embarazadas, es de gran utilidad en embarazos con riesgos para hiperplasia suprarrenal congénita o para enfermedades ligadas al cromosoma X. El presente estudio tuvo objetivo evaluar la factibilidad y desempeño diagnostico de la determinación del sexo fetal a través del análisis por PCR en tiempo real de ADN fetal libre en plasma de embarazadas . Se extrajeron 10 mL de sangre periférica a 134 pacientes embrazadas entre las 5 y 32 semanas de gestación, se separó el plasma y se efectuó extracción de ADN. Las muestras se analizaron mediante PCR en tiempo real amplificando el marcador DYS 14 presente en el cromosoma Y. El sexo fetal se confirmo mediante ecografia realizada entre las semanas 20 y 32. la sensibilidad y especificidad de la técnica para detectar el sexo fetal fue 98.5%y del 80,7% respectivamente. La menor edad gestacional de diagnóstico fue 5 semanas. La técnica implementada ha mostrado un desempeño diagnostico similar al descrito en la bibliografía...

[Epidemiology of hemolytic uremic syndrome in two regions of Buenos Aires Province]. / Epidemiología del síndrome urémico hemolítico en dos regiones de la Provincia de Buenos Aires.

The objectives of this study were (a) to describe and estimate the frequency of hemolytic uremic syndrome (HUS) in rural and urban populations in two regions of Buenos Aires Province, and (b) to compare the presentation and distribution of factors hypothetically associated with HUS. A total of 82 HUS cases, recorded during the years 2005-2010 in rural and urban areas of the south-central region of Buenos Aires Province, were clinically and epidemiologically characterized. Statistical data analysis included Chi square or Fisher test and median test. The incidence rate of HUS was significantly higher in the rural population, being 12.7 cases per 100 000 (CI 0-23.5) in rural inhabitants vs. 7.1 cases per 100 000 (CI 0-9.5) in urban inhabitants. The median age of the patients was 27 months (5-139 months), significantly lower in children from the rural area. This could be explained by a more frequent contact with bovine feces, the consumption of raw milk and a higher proportion of relatives who work in risk labors found in the rural population. Although HUS is often associated with the consumption of undercooked minced meat, most of the children cases here included did not present this antecedent. Clinical manifestations were similar in both subpopulations. One-third of urban patients had received antibiotics prior to HUS development.

Epidemiología del síndrome urémico hemolítico en dos regiones de la Provincia de Buenos Aires / Epidemiology of hemolytic uremic syndrome in two regions of Buenos Aires Province

Los objetivos de este estudio fueron describir y comparar la frecuencia del síndrome urémico hemolítico (SUH), registrada durante el periodo 2005-2010 en pobladores rurales y urbanos de la región centro-sur de la provincia de Buenos Aires y caracterizar la distribución de factores hipotéticos asociados al SUH en ambas poblaciones. Se caracterizaron 82 casos de SUH clínica y epidemiológicamente. Para el análisis estadístico de los datos se utilizó el test de Chi² o test exacto de Fisher cuando fue necesario, y el test de la mediana. La incidencia específica fue 12.7 casos cada 100 000 habitantes rurales (IC 0-23.5) y 7.1 casos cada 100 000 habitantes urbanos (IC 0-9.5). La mediana de la edad en el total de los pacientes estudiados fue de 27 meses (5-139 meses), siendo significativamente más baja en los niños del área rural. Estos resultados podrían explicarse por el contacto más frecuente con materia fecal de bovinos, el mayor consumo de leche sin pasteurizar y la mayor proporción de familiares que realizan actividades de riesgo, encontrados en la subpoblación rural. Aunque el SUH es una enfermedad que se asocia frecuentemente con el consumo de carne picada, la mayor parte de los niños que enfermaron no presentaron este antecedente. Las manifestaciones clínicas fueron semejantes en ambas subpoblaciones. Un tercio de los pacientes urbanos había recibido tratamiento con antibióticos previo al desarrollo del SUH.

The objectives of this study were (a) to describe and estimate the frequency of hemolytic uremic syndrome (HUS) in rural and urban populations in two regions of Buenos Aires Province, and (b) to compare the presentation and distribution of factors hypothetically associated with HUS. A total of 82 HUS cases, recorded during the years 2005-2010 in rural and urban areas of the south-central region of Buenos Aires Province, were clinically and epidemiologically characterized. Statistical data analysis included Chi square or Fisher test and median test. The incidence rate of HUS was significantly higher in the rural population, being 12.7 cases per 100 000 (CI 0-23.5) in rural inhabitants vs. 7.1 cases per 100 000 (CI 0-9.5) in urban inhabitants. The median age of the patients was 27 months (5-139 months), significantly lower in children from the rural area. This could be explained by a more frequent contact with bovine feces, the consumption of raw milk and a higher proportion of relatives who work in risk labors found in the rural population. Although HUS is often associated with the consumption of undercooked minced meat, most of the children cases here included did not present this antecedent. Clinical manifestations were similar in both subpopulations. One-third of urban patients had received antibiotics prior to HUS development.

Factors associated with sporadic verotoxigenic Escherichia coli infection in children with diarrhea from the Central Eastern Area of Argentina.

Verotoxigenic Escherichia coli (VTEC) are one of the most important emerging foodborne pathogens and the principal cause of hemolytic uremic syndrome (HUS). This entity has been recognized worldwide as a priority issue in the field of zoonoses and public health, and Argentina is the country with the highest incidence of HUS in children less than 5 years of age.The lack of specific treatment, combined with the high morbidity rate of VTEC infection, makes prevention the main tool for reducing the incidence of HUS. The current work aimed at assessing the factors associated with sporadic VTEC infection in children with acute diarrhea from the Central Eastern area of Argentina where the incidence rate of HUS in children under 5 is the highest worldwide. A univariate analysis was performed to identify potential factors associated with VTEC infection by calculating odds ratios (OR) with 95% confidence intervals (CI). Then, a multivariate logistic regression model was performed. Interaction and association between significant factors were checked. "Recent consumption of food prepared outside home" (OR: 2.4, 95% CI 1.05-5.7) and "recent vegetables consumption" (OR=0.4; 0.2-0.8) were identified as independent factors associated with VTEC infection. We believe that the data obtained from this study further the current knowledge about the epidemiology of VTEC infection in Argentina and could be considered when planning strategies for the prevention of the disease.

Role and clinical course of verotoxigenic Escherichia coli infections in childhood acute diarrhoea in Argentina.

The aim of this study was to investigate the role and clinical course of verotoxigenic Escherichia coli (VTEC) infections in children with acute diarrhoea from Argentina, the country with the highest worldwide incidence of haemolytic uraemic syndrome (HUS). To accomplish this objective, 437 samples from children up to 6 years old with acute diarrhoea were collected and processed. More than 60 % of the children studied presented watery or mucous diarrhoea without blood, and in 25.2 % of the cases the samples contained blood. In a first screening, a multiplex PCR was performed to detect the presence of the vt(1), vt(2), eae, ehxA and saa virulence genes. The strains were then isolated and analysed to characterize their serotypes, virulence genes, antibiotic susceptibility profiles and verotoxin (VT) production. Forty-four of the 437 samples (10.1 %) were positive for VTEC virulence genes. VTEC-infected patients presented different types of diarrhoea (27.3 % belonged to the non-bloody type). Several serotypes and virulence genotypes were found. Isolates belonged to the serotypes O157 : H7, O145 : H(-), O26 : H11, O121 : H19, O111 : H2 and O118 : H2. HUS developed in 16 (36.4 %) patients positive for VTEC virulence genes. All of the VTEC isolates produced a cytopathic effect on Vero cell monolayers, confirming the ability to express VT. Despite most strains being sensitive to all of the antimicrobials studied, a positive association between clinical progression to HUS and antibiotic therapy was observed for the total number of patients studied, as well as for the VTEC(+) group. In conclusion, the data obtained in this study increase our knowledge of the role and clinical course of VTEC infection in childhood acute diarrhoea beyond bloody diarrhoea, and might be considered for the prevention, diagnosis and management of this disease. It is possible that the optimal approach for VTEC diagnosis could be using multiplex PCR to search for the presence of the vt(1), vt(2), eae and ehxA genes.