Epidemiological study of shigellosis in an urban area of Argentina.

INTRODUCTION Shigellosis represents one of the main causes of bloody diarrhoea in South America. This study aimed to establish the incidence of shigellosis in an urban zone of Buenos Aires, Argentina, by examining the type of Shigella and living conditions associated with this infection. METHODOLOGY Between January 2009 and December 2010 we analyzed shigellosis in children admitted to the public health service with bloody diarrhoea from La Plata, the capital of Buenos Aires, Argentina. A total of 372 children under 15 years old with Shigella present in their stool samples were admitted to the study. Variables studied were patient age, type of Shigella, family economic status, and access to sewage services and safe drinking water. RESULTS Shigella flexneri was found to be present in 66.8% of the cases. Incidence was 187 cases/year/100,000 children under 15 years old. Cases were mainly observed during the summer (38.5%) in the population of under 5 years old (69.1% of all cases). The risk of shigellosis increased 12 times in those children who lacked safe drinking water and this risk increased 1.5 times in the population without sewage services. Fewer cases of shigellosis were noted in downtown areas, while hot spots were identified in the suburbs. Treating one case of shigellosis has a local cost of US $976 while assuring safe drinking water and sewage services for one family costs US $634.  CONCLUSION Incidence of shigellosis in urban areas is associated with quality of water and sewage services. Policies aimed at providing education and improving public utilities networks can help to reduce the incidence of shigellosis.