More than two decades after DDT was removed as the number-one weapon against malaria, the spread of the disease continues to be a major problem for Central American countries.

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The insecticide DDT, containing a highly toxic and persistent organic chlorate, was used in the isthmus until the 1980s as a strategic weapon against the anopheles mosquito that transmits malaria to humans via bites containing the protozoa Plasmodium falciparum, which causes the feverish illness.

For reasons of public health, 85,000 tons of DDT were applied in Central America. The chemical was also used extensively as an agricultural pesticide, according to a study sponsored by the Pan-American Health Organization (PAHO).

In the region, 1.43 cases per 1,000 inhabitants were recorded in 2000, according to PAHO.

But the mosquito's at least partial resistance to replacement insecticides, like deltametrine, utilized for the past several years in Panama, obligated the use of organic phosphate phenitrothion, says Elsa Arenas, chief of the Health Ministry's disease vector control office.

“The regions of Ngöbe Buglé, in the western province of Bocas del Toro, and the northeastern Kuna Yala, on the Colombian border, are suffering a true epidemic caused by the Plasmodium falciparum,” exacerbated since May, she told Tierramérica.

“In addition to treating infected persons with the medications chloroquine and primaquine and eliminating the mosquito breeding sites using biological controls, in the case of Kuna Yala we employed phenitrothion, the use of which is strictly controlled in Panama,” said Arenas.

“We'll remain on the alert because the risk of contagion in regions that are now under control will be extremely high as long as the mosquito exists in tropical areas,” said the health ministry official.

The epidemic can be managed, but not eradicated, due to the fact that the habitat is ideal for anopheles reproduction, Arenas said. As of the last week of July, there were 2,765 people reported with malaria this year in Panama, compared to 1,426 in the same period in 2002.

The flows of human migration towards developed areas within each country or within the region are considered contributing factors to the transmission of the disease and new epidemics.

“In Guatemala, the problem historically was concentrated in the north of the country, in the departments of El Petén, Alta Verapaz, Izabal and El Quiché. But in the past five years it reached the southern coast,” Francisco Ardón, chief of epidemiology at the Guatemalan Ministry of Health, told Tierramérica.

Malaria arrived in Escuintla, Suchitepéquez and Retalhuleu, on the Pacific, where major efforts are underway to combat the disease-transmitting mosquito.

But by Jul. 19 there were 42,744 cases of malaria so far this year, a slight improvement on the 46,551 recorded in the same period last year.

Ardón attributes this decline in cases to the prevention campaign. He also underscores that there was only one malaria-related death in the past 18 months.

Fumigations against the mosquitoes do not use DDT, which has been banned in Guatemala since 1974. But Edwin Garzona, consultant with the Center for Legal Environmental and Social Action, said in a conversation with Tierramérica that the pesticide continues to be smuggled into the country.

Ardón acknowledged that DDT trafficking may be occurring, but the Ministry of Health does not have the resources to investigate smuggling, allegedly perpetrated by farmers.

With 321 km of coastal plains into which numerous rivers flow, El Salvador also has conditions propitious for the propagation of malaria, which in the early 20th century was the leading cause of death in this country.

But as of mid-July, only 21 cases had been recorded in El Salvador, compared to 70 in 2002, according to official figures.

“Civil society's participation has been important in achieving results in areas considered high risk. Currently we have 3,500 participants,” whose efforts have permitted early diagnosis, says doctor Juan Hugo Francia, head of the malaria prevention program at the Salvadoran Ministry of Public Health.

Household spraying with DDT was suspended in El Salvador in 1968, when the mosquito was found to be resistant to the pesticide, not because of the pesticide's toxicity.

Fumigation of homes continued with piretroid poisons, used only in emergency situations, and at a cost four times that of DDT.

Malaria affects some 300 million people in developing countries and claims a million lives worldwide each year.