Elimination of Malaria

The World Health Organization (WHO) estimates that malaria kills over 1 million people each year in sub-Saharan Africa and causes 300 million cases of acute illness each year, 75% of which are in children.  Of the entire sub-Saharan Africa area, Kenya has suffered greatly from the devastation that this parasite and disease has infected its country.  While significant funds have been spent by the Kenyan government in the battle against the mosquito and the malaria parasite that it carries, the truth exists that all of these efforts have not diminished the instances of this disease or the loss of life that occurs year after year.  The challenge of malaria has historically been addressed by providing mosquito nets, indoor spraying and inoculations for pregnant women; however, despite years of effort and high adoption rates of mosquito nets, the frequency of malaria just continues to increase – crippling the health and economic development of Kenyan people.  As part of our goal of providing for the needs of the people of this region, the East Africa Partnership (EAP) is proposing to use a newly-developed, but well-tested, externally sprayed insecticide to reduce the mosquito population.

Problems with externally sprayed agents have been well-documented; safety issues with humans and livestock, environmental concerns, resistance to chemical agents, and the inability to function in rainy or wet environments have seemed like insurmountable concerns and have shifted focus to insecticide-impregnated bed nets and internal spraying.  By 2006 in Kenya, more than 65% of children and pregnant women were using impregnated bed nets, which are provided for free (WHO, 2008).  About 7 million nets were provided in 2006 saving 7 lives per 1000 children protected, yet the incidence of malaria has increased in 4 of the last 5 years in Kenya with 11.3 million having the disease and 27,000 deaths.  A new solution is needed.

While these historical treatment programs have created some improvement with the malaria situation in the developing world, and other new projects like the potential malaria vaccine undergoing clinical trials offer more hope, history has shown that the only way that malaria has been eradicated—from North America to Europe to Brazil to Egypt—has been through the systematic use of externally sprayed insecticides.  The East Africa Partnership has identified an insect control agent that is not subject to the problems seen with previous products, specifically this insecticide has the following characteristics:  safe for humans and animals, works equally well in both dry and wet climates, kills both adult and larvae mosquitoes, safe for the environment, utilizes one of Kenya’s natural resources (pyrethrum) and is a cost-effective way of eliminating the malaria carrying mosquito with resistance.

The Anopheles mosquito, the primary genus in sub-Saharan Africa, rests near stagnant water and in acacia trees after feeding.  External treatment has been a challenge in Kenya due to the rainy seasons, frequency of water holes, and lack of infrastructure, but has been used effectively to eradicate this species in regions with similar climates, including Egypt and Brazil in the 1930s and 40s (Control of Malaria: Historical Perspective, 1995).  The Garki Project in Nigeria (1969-1976, ibid.) demonstrated the difficulty of residual spraying alone as there was a very high transmission intensity; testing showed that insecticide was very effective against the vectors, but a 90% reduction of vectorial capacity reduced malaria prevalence by only 25%.  The problem was that mosquitoes rest outdoors after blood feeding (exophily); this project corrects this problem.
               
An insecticide has been created and tested to overcome the problems associated with external spraying and effectively reduce the mosquito population.  It is a combination of two naturally existing killers of mosquitoes.    It is relatively inexpensive to produce, breaks down without residual effects, can be easily applied in any climate or location, lasts up to 30 days in the rain, has not shown any development of resistance since it contains 6 different and fatal esters and, most importantly, is capable of killing mosquitoes in wet or dry conditions without any effect on humans, animals, or the environment.  The agent has been approved to kill mosquitoes and certified as safe for both humans and animals by the United States Environmental Protection Agency (EPA).  It is effective in killing both adult mosquitoes and larvae, and will be applied both around the watering holes where the mosquitoes breed and in acacia trees where the female mosquitoes (which bear the malaria parasite) reside. 

A recent study (2009) by A. Read concluded that if insecticides targeted old mosquitoes, they could provide effective malaria control, while “only weakly selecting for resistance.  This alone would greatly enhance the useful life span of an insecticide.”  The female mosquito rests near the water after taking a blood meal for several days before producing eggs.  During this period of time, spraying is extremely effective.  The maximum flight range of the mosquito during wet season is 1 km.  In addition, Fillinger (2006) concluded that larvicing reduced Anopheles larval density by 95% and human exposure to bites from adults by 92% for $0.9/person/year.  The proposed insecticide program attacks the elderly mature mosquito and perhaps larvae.  While pyrethrins, synthetic pyrethrum, have shown some development of resistance, Elizabeth Juma told the Nairobi Symposium in April 2009 that pyrethroid insecticides in Kenya remained effective and natural pyrethrum has never been known to produce insecticide resistance.
               
The East Africa Partnership (EAP) has been establishing health centers in remote areas of Kenya and Tanzania to treat the local population.  Each center addresses the needs of 25,000 mostly nomadic people.  The centers are supplied with diagnostic laboratory equipment, a luxury seldom available in district hospitals, much less health clinics.  The employees at these clinics provide excellent care as they have been trained for 2-4 years by American physicians, nurses, laboratory technologists and other medical professionals.  These clinics are ideal for conducting this type of trial; they have reliable data on each case of malaria, they are remote and isolated so patients return repeatedly, and they diagnose malaria with proper lab equipment.
               
The Kenyan government plans to give to the EAP permission to perform a controlled insect control trial at up to four specific locations in Kenya that each represent a 16 kilometer radius in order to demonstrate the effectiveness of the this insect control product.  The Kenyan government will provide the following:  funding for the trial, assistance in the monitoring and review of the results from the mosquito control trial area.  If this testing program is successful, this program can be expanded to eliminate malaria (and other insect carried diseases such as leishmaniasis) through external spraying around water holes and resting areas for adult mosquitoes, saving the government millions on the treatment of malaria and improving the health of its people.

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