Escherichia coli shigatoxigénica en animales relacionados con casos de diarreas sanguinolentas o síndrome urémico hemolítico y prevalencia en roedores de la Ciudad de Buenos Aires / Shiga toxin-producing escherichia coli in animals related to cases of bloody diarrhea

Escherichia coli shigatoxigénica (STEC) es un patógeno endémico en Argentina, responsable de diarrea aguda sanguinolenta (DAS) y/o síndrome urémico hemolítico (SUH). La correlación entre SUH y alimentos contaminados ha sido documentada, aunque no siempre se estableció la fuente de infección. La ruta de contagio persona-persona es relevante. Dados los registros previos de prevalencia de STEC en animales de compañía y los hábitos de convivencia humano-animal en centros urbanos, es necesario evaluar la ruta mascota-persona. A su vez, los roedores podrían tener un papel epidemiológico en la endemia. OBJETIVO: Estudiar posibles reservorios animales relacionados con casos de SUH/DAS en la Ciudad Autónoma de Buenos Aires y estimar la prevalencia de STEC en roedores. MÉ-TODOS: Se intervino en 28 casos de SUH y 49 de DAS. Se realizó rastrillaje de cepas STEC por PCR a partir de hisopados rectales de los animales vinculados a cada caso. La prevalencia en roedores se estimó por PCR de sus hisopados rectales. RESULTADOS: Se aislaron cepas STEC en 1/10 caninos y 1/3 felinos con vivientes con casos de SUH, y 1/9 felinos contacto con casos de DAS. Rattus rattus fue hospedero de cepas STEC en 33% de los animales capturados en focos de SUH. En roedores, la prevalencia fue de 3,1%. CONCLUSIONES: Las cepas STEC circulan en los animales que conviven o tienen al menos un hábitat compartido con la población en riesgo, quienes podrían participar en la transmisión del agente. Es necesario reevaluar las intervenciones sanitarias en focos y en programas de control de SUH/DAS

Shigatoxigenic Escherichia coli(STEC) is an endemic pathogen in Argentina, which causes bloody diarrhea (BD) and/or hemolytic uremic syndrome (HUS).The co-relation between HUS and contaminated food has been documented, although the source of infection was not always established. Person-to-person route of infection is relevant. Taking into account previous STEC prevalence data in companion animals and the habits of human-animal coexistence in urban centers, it is necessary to evaluate pet-to-person transmission. On the other hand, rodents may also play an epidemiologic role in the endemic transmission. OBJECTIVE: To study potential animal reservoirs related to HUS and BD cases in the City of Buenos Aires and to estimate the prevalence of STEC in rodents. METHODS: An intervention was conducted in 28 cases of HUS and 49 of BD. Screening for STEC was performed by PCR from rectal swabs of linked animals to each case. The prevalence in rodents was estimated by PCR from rectal swabs. RESULTS: STEC strains were isolated in 1/10 dogs and 1/3 cats cohabiting with HUS cases, and in 1/9 cats in contact with DAS cases. Rattus rattus was host of STEC strains in 33% of the animals captured in HUS areas. In rodents, the prevalence was 3.1%. CONCLUSIONS: STEC strains circulate in animals that live withor share at least the same habitat with the population at risk, and could participate in the transmission of the agent. It is necessary to re-evaluate health interventions both in outbreaks and in control programs of HUS/BD

Prevalence of infection with hantavirus in rodent populations of central Argentina

We studied hantavirus seroprevalence and virus variability in rodent populations in Diego Gaynor, northwest of Buenos Aires province, Argentina. Rodent samplings were conducted in railroads and cropfield borders in March and July 1999, September and December 2000, and March 2001. Antibody detection was performed by an enzyme link immunosorbent assay (ELISA), using the recombinant nucleoprotein of Andes (AND) virus as antigen. Tissue samples were taken from positive antibody individuals in order to confirm the presence of hantavirus genomic material and to identify virus genotypes. Akodon azarae was the most abundant species, followed by Oligoryzomys flavescens, while Calomys laucha and C. musculinus were rarely caught. We found a rate of seroprevalence of 9.3 percent for a total sample of 291 A. azarae and 13.5 percent for 37 O. flavescens. After molecular analyses of hantavirus, we confirmed the presence of hantavirus genomic material in 16 individuals with ELISA (+) results and two individuals with ELISA (-). Four amplimers for each species were sequenced and compared to the corresponding sequences of representative hantaviruses. We identified the AND Cent Lec from three O. flavescens, and the Pergamino virus from four A. azarae and from one O. flavescens. A. azarae males had higher seroprevalence than females, and heavier individuals showed higher seroprevalence than lighter ones. We did not find seroprevalence differences according to sex in O. flavescens, although this result may have been produced by the low sample size. The lowest seroprevalence was found in a period of high rodent density, when juveniles prevailed in the population. We found higher seroprevalences than those detected in previous studies for other localities of central Argentina where cases of hantavirus pulmonary syndrome (HPS) have been reported. The presence of AND Cent Lec virus in rodent populations of the study area, which is responsible of HPS cases in central Argentina, suggests that human populations are at risk of HPS disease, although there were not reported cases of this disease until today