Aflatoxin in Kenya: Finding Our Way Through the Maize

In April 2004, illness and death plagued rural Kenya. No one knew what the source could be. At the core of this mystery, however, was an outbreak— jaundice with a high rate of fatality in the districts of Makueni and Kitui, Eastern Province. Officials were at a loss for answers. Stumped, they were catapulted into a mission to discover the cause of the illness.

The Kenya Ministry of Health (MOH) invited several organizations and agencies to participate in the outbreak investigation including CDC Kenya and CDC’s National Center for Environmental Health (NCEH)
(Health Studies Branch HSB)

Mystery Solved

In the end, testing soon revealed the culprit was high levels of aflatoxin in homegrown maize. The 2004 outbreak was one of the largest and most severe outbreaks of acute aflatoxicosis documented worldwide.

Since the 2004 outbreak, there have been smaller recurring outbreaks and ongoing challenges with aflatoxin control and prevention. NCEH/HSB has continued to work with the Kenyan government on prevention strategies to reduce exposure and mitigate contamination. These ongoing efforts include:

• Identifying risk factors associated with aflatoxin contamination such as improper storage, drying practices, and food insecurity.
• Identifying the high-risk season for contamination. Outbreaks seemed to recur immediately following the major harvest season—between April and June.
• Increasing public awareness with education campaigns about aflatoxin in general, health effects related to exposure, and methods to prevent exposure.
• Increasing public health capacity for testing maize at the household level. Scientists from HSB and the MOH modified a rapid aflatoxin screening assay. This assay, normally used in developed countries, was used in rural Kenya to assess whether aflatoxin levels in grains were above or below the Kenyan regulatory limit.
• Conducting a national assessment of commercial products to identify other sources of aflatoxin exposure beyond the household farm.
• Conducting a national assessment of human aflatoxin exposure measured in serum to determine the extent of exposure across all regions of Kenya and identify at-risk populations.

What is Aflatoxin?

Aflatoxin is a fungal toxin that commonly contaminates maize and other crops during production, harvest, storage, or processing. In Kenya, acute aflatoxin poisoning results in liver failure and death in up to 40% of cases.

In developed countries like the United States, commercial crops are screened routinely for aflatoxin using detection techniques that are performed in a laboratory setting.

NCEH: Using Innovative Laboratory Science

NCEH’s Division of Laboratory Sciences played a major role in the success of the outbreak investigations. The lab, through its use of sophisticated laboratory measurement techniques, provided the best possible evidence that Kenyans were exposed to aflatoxin. One such technique had never before been used in an outbreak. It directly measured toxins in blood samples from people who had eaten the maize. As a result, officials had a more accurate assessment of exposure than otherwise would have been possible. These efforts not only helped stem the outbreaks in Kenya, but have also been key in determining the extent of human exposure across all regions of Kenya.