National Farm Medicine Center Director Matthew Keifer, M.D., recently traveled to the West African nation of Ghana to develop a pilot-testing program to monitor pesticide applicators for over-exposure to anti-malaria chemicals they apply.

The President’s Malaria Initiative (PMI), credited with dramatic reductions in child mortality in sub-Saharan Africa, selected Dr. Keifer to advise on how PMI should monitor, what tools to use, how to train people running the monitoring program and how to use information gathered from the program.

National Farm Medicine Center Director Matthew Keifer, M.D., recently traveled to Ghana to develop a pilot-testing program to monitor pesticide applicators for over-exposure to anti-malaria chemicals they apply as part of the President’s Malaria Initiative.
Dr. Keifer has worked on or designed similar pesticide applicator monitoring programs in Washington state and Nicaragua. Prior to joining NFMC in 2010, Keifer was co-director of the Pacific Northwest Agricultural Safety and Health Center, directing numerous community-based research projects focusing on farm worker health and pesticides. For two years before that he was a pesticide epidemiologist in Nicaragua on behalf of CARE International.

“PMI protects millions of people from one of the world’s most deadly diseases,” said Dr. Keifer, who traveled to Ghana in late March. “However, people who do the day-to-day work of controlling mosquito vectors which transmit malaria also need protection. Chemicals they use can make them sick but if we monitor them closely, we can keep them healthy and on the job, saving lives.”

Key to the program will be monitoring blood levels of the enzyme cholinesterase in applicators. Cholinesterase is needed for proper functioning of nervous systems of humans, animals and insects. Certain chemical classes of pesticides, such as organophosphates (OPs) and carbamates (CMs), work against undesirable insects by interfering with, or “inhibiting,” cholinesterase. While effects of cholinesterase-inhibiting chemicals are intended for insects, these products can also be toxic to humans.

When human cholinesterase levels are low because of excessive inhibition from pesticides, the nervous system can malfunction, producing pesticide-poisoning symptoms such as fatigue, lightheadedness, nausea, vomiting, headaches and seizures. If levels get low enough, subsequent exposure to OP insecticides can result in death.

The purpose of regular monitoring of cholinesterase levels is to alert the exposed person to any change in the level of this essential enzyme before it can cause serious illness. Ideally, a pre-exposure baseline cholinesterase value should be established for any individual before they come in regular contact with organophosphates and carbamates. Fortunately, inhibition of cholinesterase can be reversed and cholinesterase levels will return to normal if pesticide exposure is stopped.

Launched in 2005, PMI is an expansion of U.S. government resources to reduce the burden of malaria and help relieve poverty in Africa. PMI is an interagency initiative led by the U.S. Agency for International Development and implemented together with the Centers for Disease Control and Prevention.

More than 30 million Africans are protected from malaria each year as the result of PMI-supported indoor spraying.