Outbreak of Aflatoxin Poisoning - Eastern and Central Provinces, Kenya, January - July 2004

CDC were invited by the Kenya Ministry of Health (KMOH) to participate in the investigation of an outbreak of jaundice with a high case-fatality rate (CFR) in the districts of Makueni and Kitui, Eastern Province. Preliminary laboratory testing of food collected from the affected area revealed high levels of aflatoxin, suggesting that the outbreak was caused by afla-toxin poisoning, as was a previous outbreak in the same area in 1981 (1). In the United States, aflatoxin concentrations are limited to 20 parts per billion (ppb), a level also adopted by Kenyan authorities. The 2004 outbreak resulted from widespread aflatoxin contamination of locally grown maize, which occurred during storage of the maize under damp conditions. Urgent replacement of the aflatoxin-contaminated maize with noncontaminated maize proved to be a critical intervention; however, as of July 21, a limited number of new cases continued to be detected. This report summarizes the preliminary results of the outbreak investigation. Aflatoxin poisoning likely will continue to be a public health problem until culturally appropriate storage methods for dry maize are implemented by the local population. In addition, enhanced surveillance for human aflatoxin poisoning and testing of commercially sold maize for aflatoxin levels will lead to long-term improvements in public health. Joint KMOH and CDC teams conducted patient interviews and reviewed medical records dating back to January 1, in three health facilities in the Makueni and Kitui districts. Additional case finding was conducted through similar patient interviews and retrospective record reviews in seven health facilities in adjacent districts of Eastern Province (Machakos, Embu, Mbeere, and Mwingi districts) and Central Province (Thika district) and at Kenyatta National Hospital in Nairobi (Figure 1). Large-scale active surveillance occurred from early May to late June. As of July 21, three health facilities in Makueni and Kitui districts continued to be monitored for new cases. A convenience sample of 20 patient households was visited to assess the occurrence of jaundice in nonhospitalized household members and to inspect food quality and storage. In this investigation, a case of suspected aflatoxin poisoning was defined as a case of acute jaundice that occurred after January 1, in a resident of Eastern or Central Province or a case diagnosed at Kenyatta National Hospital in a patient who was not known to have chronic liver disease or any other cause of jaundice. As of July 20, a total of 317 cases had been reported, with 125 deaths …