The proportion of diarrheal illnesses of unknown origin that were associated with small round virus (SRV, 23-38 nm) particles among children <2 years old attending an outpatient clinic in Baltimore was determined. During a 9-month period, stool specimens from 188 patients with acute diarrhea and 108healthy age-matched control children were examined for enteric bacterial pathogens, protozoa, enteric adenovirus, and rotavirus. An enteropathogen was identified in 75 patients (40%) and in 21 controls (20%). A random sample of specimens without an identifiable pathogen wasthen examined for SRV particles by immune electron microscopy (IBM) using commercial human gamma globulin. Viruses of 26-30 nm diameter that were not enteroviruses were detected in specimens from 9 (12.5%) of the 7l patients and 1 (1.8%) of the 53 control subjects (P < .04). Of6 patients with available acute and convalescent sera, 4 demonstrated a significant immune response when tested by IBM. All patients experienced a mild, self-limited (1–3 days) illness. These findings suggest that SRV may be endemic in the Baltimore community and may result in clinically significant diarrheal illnesses.
Detection by Immune Electron Microscopy of 27-nm Viral Particles Associated with Community-Acquired Diarrhea in Children