The President's Malaria Initiative (PMI), credited with dramatic reductions in child death rates in sub-Saharan Africa, has selected the director of the National Farm Medicine Center (NFMC) at Marshfield Clinic Research Foundation to design a program that monitors its pesticide applicators for overexposure to those chemicals.
Dr. Matthew Keifer will advise the PMI on how to monitor; what tools to use; how to train people running the program; and how to use information gathered from monitoring. Keifer will teach program staff how to monitor pesticide chemicals that can make people sick.
Launched in 2005, the PMI is an expansion of U.S. government resources to reduce the burden of malaria and help relieve poverty in Africa. PMI is led by the U.S. Agency for International Development and implemented 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. In 2010, there were about 219 million malaria cases worldwide and an estimated 660,000 malaria deaths, 90 percent of which were in Africa, according to the World Health Organization.
"The PMI protects millions of people from one of the world's most deadly diseases," Keifer said. "However, people who do day-to-day work of controlling mosquito vectors that 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."
Keifer has worked on or designed similar monitoring programs in Washington and Nicaragua. Prior to joining NFMC in 2010, Keifer co-directed the Pacific Northwest Agricultural Safety and Health Center, leading many community-based research projects focused on farm worker health and pesticides.
Key to the program is monitoring blood levels of the enzyme cholinesterase in workers spraying the pesticide. Cholinesterase is needed for proper functioning of human, animal and insect nervous systems.
Certain chemical classes of pesticides, such as organophosphates and carbamates, 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 organophosphate 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 individuals before they come in regular contact with organophosphates and carbamates. The breakdown of cholinesterase can be reversed and cholinesterase levels will return to normal if pesticide exposure is stopped.
Marshfield Clinic Research Institute (MCRI), a division of Marshfield Clinic, was founded in 1959. It's the largest private medical research institute in Wisconsin. MCRI consists of research centers in clinical research, agricultural health and safety, epidemiology, human genetics and biomedical informatics. Marshfield Clinic investigators publish extensively in peer-reviewed medical and scientific journals addressing a wide range of diseases and other health issues, including cancer, heart disease, diabetes, eye disease, neurological disease, pediatrics, radiology, women's health, agricultural safety and genetics.
The Marshfield Clinic system provides patient care, research and education with more than 50 locations in northern, central and western Wisconsin, making it one of the largest comprehensive medical systems in the United States.