Rotavirus and hepatitis A virus in market lettuce (Latuca sativa) in Costa Rica.

We assessed the presence of rotavirus and Hepatitis A virus in lettuce bought in farmer markets from San José, Costa Rica, during months of low (April-June) and high (December-January) incidence of diarrhea associated with rotavirus, respectively. Lettuce samples were pooled and evaluated for rotavirus by enzyme-linked immunosorbent assay (ELISA) and for Hepatitis A virus by radioimmunoassay, polymerase chain reaction (PCR) and electron microscope. Three sample pools, collected during the period of high prevalence of diarrhea, were positive for rotavirus by ELISA and in one of them rotavirions were visualized by electron microscopy. Two samples pools collected during the same period were positive for Hepatitis A virus as shown by PCR. In almost all the pools fecal coliform bacteria were detected by cultivation and bacteriophages were visualized by electron microscopy.