Seasonal fluctuations in the occurrence of enterotoxigenic bacteria and rotavirus in paediatric diarrhoea in Addis Ababa.

This study (March 1977-February 1978) was performed at the Ethio-Swedish Pediatric Clinic, Addis Ababa, to determine whether there were any seasonal fluctuations in the occurrence of diarrhoea associated with enterotoxigenic enterobacteria (ETEB), rotavirus and two parasites (Giardia lamblia and Entamoeba histolytica).A total of 1161 children (962 patients and 199 controls) were investigated. ETEB were isolated in 12.2% of the patients and 4.5% of the controls, rotavirus in 27.8% and 8%, and parasites in 6.8% and 1%, respectively. There is a statistically significant difference in the isolation rates between patients and controls (P<0.001 for rotavirus, P<0.01 for ETEB and parasites). Rotavirus was most prevalent in the 7-12 months age group and ETEB during the second year of life, while parasites showed a continuous increase with age.Two peaks in the occurrence of ETEB were found during the year, the first in August (32.6%), the second in January (19.2%). Two peaks for rotavirus though not as distinct as for ETEB, were seen in June (42.7%) and November (36.4%). The isolation rate of parasites showed no consistent pattern during the year.This study suggests a seasonal occurrence of ETEB and rotavirus but with no apparent correlation to climatological factors.