RESUMEN
In September 1987 an outbreak of exanthematous illness ressembling erythma infectiosum occurres at an elementary school of Säo Paulo city. Attempts to isolate virus from the nasofaryngeal secretion and urine and serum samples collected from the ill children in acute phase of illness resulted negative. Nevertheless, parvovirus-like particles of about 24 nm in diameter were observed by negative staining electron microscopy in concentraded urine of seven out of eight ill patients and in nasopharyngeal secretion of one out of four patients. No similar viral particle was observed in concentred urine samples collected on the same occasion from their classmates without evident signs of illness. This is a proposal of an alternative test for a rapid and sensitive presumptive diagnosis of human parvovirus infection