Implications of acute gastroenteritis in human health by norovirus as the product of contaminated water

In July 2010, an outbreak of acute gastroenteritis emerged among residents of the main city of the Northern Region of Costa Rica, Ciudad Quesada. This research was carried out to explore and characterize the outbreak in that rural area. Surveillance data and patients' medical records were analyzed to conduct a descriptive study between July 8th and July 14th, 2010 at the Canton of San Carlos. A data sheet (Ficha Colectiva de Investigacion VE 0.2) was applied to gather information from the patients. In order to detect the presence of enteropathogens, an ELISA test was applied to stool samples. Water samples were also analyzed to detect bacteria and fecal coliforms. A total of 352 cases were confirmed in the studied region. The most frequent symptoms among confirmed cases were diarrhea (94.2%), nausea (92.7%) and vomiting (91.7%). The average age of the patients was 29 years (SD 15.8), 50.8% corresponded to female subjects. The most affected age group is represented by infants from 1 to 4 years old (attack rate 18.2 / 1,000 inhabitants) being the downtown the most affected area of Ciudad Quesada. Norovirus was isolated in five out of six stool tests. Water testing only identified the presence of Escherichia coli. The findings suggest that the Norovirus was transmitted by fecal contaminated water. This is the first documented outbreak caused by this agent in the Northern Region of the country. It is recommended to improve the monitoring of water quality and promote the use of safe water among residents. A major limitation lies in the fact that viral detection tests in water are not available in the country.