Taking a Bite Out of Malaria: Part II

Beginning with the Second World War, the fight against malaria was focused on killing mosquitoes with DDT (dichlorodiphenyltrichloroethane).

This powerful insecticide, which proved highly effective against malaria, also produces serious negative health consequences. It enters the food chain and poisons humans, staying in their bodies for many years and causing numerous toxic effects.

Given the threat that malaria poses to public health in Latin America and the Caribbean, the Pan American Health Organization (PAHO) has promoted an alternative to DDT through an approach that is sustainable, safer for human health, and cost-effective.

In cooperation with the governments of eight countries — Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, and Panama — and with the support of the Global Environment Facility (GEF), PAHO began a program in 2004 to combat malaria in the Meso-American region without using toxic insecticides.

In places where this effort is underway, the DDT/GEF/PAHO project has already helped to control the illness. It has also brought communities closer together and strengthened their organizational capacity.

The project was implemented initially in Mexico, where the National Institute for Public Health developed the methodology with support from Canada’s International Development Research Centre.

Malaria is currently endemic to 107 countries — 21 in the Americas — and represents a threat to half the world’s population. It is estimated that nearly 109 million people in Mexico and Central America live in areas with ecological and social conditions that foster transmission of the disease.

Of these, around 35 percent live in high-risk areas; thus the program’s focus on this sub-region. In the eight countries studied, 53,414 malaria cases were reported in 2006, of which nearly 96 percent were caused by the Plasmodium vivax parasite and the remaining 4% by Plasmodium falciparum.

In addition to the deaths it causes, malaria keeps millions of people from going to work or school every day. The chronic anemia it causes leaves its victims weakened for many years and causes severe damage to the liver and kidneys. Cerebral malaria causes problems with memory and learning that can last for years, and is the principal cause of death from the disease.

Because malaria results from complex interactions among four components — the parasite that causes it, the mosquito that acts as a carrier, the human whose blood attracts the mosquito, and the environment that creates the necessary conditions for the carrier’s development and survival — the best strategy against this disease is one that attacks it on all four fronts.

A comprehensive program

The anti-malaria program carried out in Mexico and Central America includes several key efforts: establishing demonstration projects that use alternative approaches to control malaria; bolstering countries’ institutional capacity to fight the disease; eliminating remnants of DDT and other so-called “persistent organic pollutants” — and strengthening the program’s administrative and management structure.

The eight countries that set up demonstration projects adopted a comprehensive “malaria vector control” model based on Mexico’s experience with the disease. Locations were selected based on the high incidence of transmission and the persistence of malaria.

The idea behind the vector control approach is to lower the morbidity and mortality rates by reducing the carrier’s ability to transmit the disease. Thus it is critical to target Anopheles' habitats by draining and filling in breeding sites, as well as cleaning up nearby houses and patios where certain types of mosquitoes may be found.

Efforts include: eliminating underwater vegetation, such as the green filament algae found in ponds; draining pools of stagnant water that collect in landfills and elsewhere; and clearing underbrush that has grown up around houses and yards. Other environmentally friendly strategies include planting insect-repellent vegetation such as neem trees and using biological larvicides and mosquito nets treated with non-toxic insecticides.

Vigilant from an epidemiological perspective is also crucial, so that people with the disease can be properly diagnosed and treated. This involves identifying the parasite with a microscope or using a rapid-diagnosis test with chemical reagents, which can be performed by individuals with minimal training.

The active, organized participation of individuals, families, and community groups in the planning, execution, and evaluation process has been a critical element of the program. Also, educational tools have been used to promote greater participation.

For example, a board game called PALU allows players to move their pieces on the board according to the level of their knowledge about the disease. Puppets make learning fun for children, and booklets on malaria have been specially designed for indigenous audiences.

Women have played a key role in these efforts, taking the lead in getting the work done and coordinating with municipal authorities and private companies to the benefit of their communities.

In terms of strengthening institutions, the program has helped develop each country’s capacity to evaluate the malaria risk at a local level and make decisions on the most appropriate intervention measures. Laboratories have been better equipped so they can analyze the amounts of residual DDT in the environment and living organisms.

One important contribution of this program is the use of a Geographical Information System for monitoring malaria in the demonstration areas, a tool developed by the Washington, D.C.-based PAHO and Mexico’s National Institute for Public Health.

Progress has also been made on the third component of the PAHO program, which involves eliminating DDT and other persistent organic pollutants.

Under the guidelines established in international agreements signed in Basel, Rotterdam, and Stockholm, final disposal is underway for 136.7 tons of DDT and 64.5 tons of other pollutants that had been stockpiled in the eight participating countries. Many of these substances were poorly stored and presented a high risk of human and environmental contamination.

The fourth component involves strengthening the program’s management and coordination. PAHO and the national health or environmental ministries of the eight governments involved have worked together — with support from the Commission for Environmental Cooperation for North America — to strengthen this aspect, through frequent consultation and coordination of activities.

Real achievements

The program has had significant achievements, notably a reduction in the number of malaria cases. From 2004 to 2007, reported malaria cases dropped by 63% in 200 demonstration communities in Mexico and Central America that had been chosen because of their historically high rate of transmission.

In El Salvador, where before 1950 malaria was the leading cause of morbidity and mortality, malaria has practically been eliminated — a result not only of this program but also other actions carried out in recent decades.

In Panama, the number of malaria cases fell from 4,500 in 2004 to 1,663 in 2007. The other countries studied showed different degrees of decline in the number of people affected.

Another result is that leaders have been mobilized and activities strengthened at the community level, with greater cooperation among different sectors and institutions. The actions taken to control malaria, moreover, have led to better hygiene practices in homes and greater public awareness about individual responsibility in controlling malaria.

The program has also promoted cross-border activities. For example, Costa Rica and Panama have held technical meetings involving information exchange, logistical support, joint emergency planning, and efforts to share experiences and systematize practices. Training has also been provided to local teams both within and outside the countries participating in the program.

In various places in the different countries, activities have been extended to other areas beyond the initial demonstration sites. Municipal and national authorities are providing support to make anti-malaria efforts sustainable.

The campaign to fight malaria not only benefits individuals who might otherwise get the disease, it also strengthens communities as they organize around a common cause and participate in clean-up activities.

Economic benefits include lower work absenteeism due to illness and lower costs because communities no longer have to purchase insecticides. In developing countries, it is clear, combating malaria also means combating poverty.