The Epicore Global Surveillance Project reports that in 1992, a large outbreak of bloody diarrhea caused by Escherichia coli O157 infections occurred in southern Africa.
In Swaziland, 40,912 physician visits for diarrhea in persons aged 5 years and older were reported during October through November 1992. This was a 7-fold increase over the same period during 1990-91. The attack rate was 42 percent among 778 residents we surveyed. Female gender and consuming beef and untreated water were significant risks for illness.
E. coli O157:NM was recovered from 7 affected foci in Swaziland and South Africa; 27 of 31 patients and environmental isolates had indistinguishable pulsed-field gel electrophoresis patterns. Compared with previous years, a 5-fold increase in cattle deaths occurred in October 1992. The 1st heavy rains fell that same month (36 mm), following 3 months of drought. Droughts, carriage of E. coli O157 by cattle, and heavy rains with contamination of surface water appear to be important factors contributing to this outbreak.
Early in November 1992, physicians arriving for duty at a small hospital on a sugar plantation in Swaziland found over 100 persons sprawled on the ground in front of the casualty department. Many had bloody diarrhea, and almost all were suffering severe abdominal pains. The next day, the number of patients with the dysenteric illness nearly doubled, yet stool specimens sent to local laboratories did not yield common parasitic or bacterial pathogens, including Shigella spp. With the etiologic agent still unknown into the 2nd week of the outbreak, specimens were forwarded to a reference laboratory in South Africa, where a surprising discovery was made: E. coli O157 had emerged in Africa.
An outbreak of E. coli O157 infections was heretofore unheard of in Africa or, for that matter, anywhere in the developing world. E. coli O157 had been isolated only once before in southern Africa, from an elderly man undergoing surgery for lower gastrointestinal bleeding in Johannesburg in 1990. Carriage of E. coli O157 by cattle, cattle deaths secondary to drought, and heavy rains that resulted in contamination of surface water were important factors contributing to the emergence of E. coli O157 in Africa. Given that drought and heavy rains will likely recur in Africa, the possibility that E. coli O157 will once again emerge to cause a major regional outbreak cannot be excluded. Clinicians need to be aware of this so that delayed diagnosis and inappropriate treatment resulting in loss of lives can be avoided.
