RIO DE JANEIRO - Chagas disease, which affects 18 million people in Latin America, can be lethal because it causes genetic alterations, according to the findings of scientists at the University of Brasilia.

In Brazil there are some six million people infected with the Trypanosoma cruzi parasite, which causes this disease and is transmitted by the Triatoma infestans, an insect known here as 'barbeiro', and 'vinchuca', 'chipo' or 'chupón' in Latin America's Spanish-speaking countries.

Chagas disease (American trypanosomiasis) kills an average of 33,000 Brazilians each year, through damage to the heart or other organs. The parasite adds its own DNA to that of the infected cells and the body's immune system attacks the altered tissue as if it were foreign, explained Antonio Teixeira, research coordinator.

This discovery opens the way to search for a cure for the disease, but even so, it is likely to take decades, he said.

SANTIAGO - The Chilean environmental group Fiscalía del Medio Ambiente presented a case before the capital's Court of Appeals to overturn a decree from Agriculture Minister Jaime Campos that authorizes the logging of native tree species, which have been declared national monuments.

The decree, according to the activists, threatens autochthonous species like the 'alerce' (Fitzroya cupressoides), 'araucaria' or monkey puzzle (Araucaria araucana) and the 'belloto' (Beilschmiedia mierssi).

The group argues that the decree is illegal and unconstitutional and also violates the international Convention on Nature Protection and Wildlife Preservation in the Americas.

According to the decree, under exceptional circumstances the cutting or removal of the national monument species may be authorized when it is necessary for carrying out ''projects or activities of national or regional interest.''

The environmentalists' claim is backed by Chilean Forest Defenders, the National Ecological Action Network and Greenpeace.

CARACAS - Two Venezuelan children died of rabies last week after being bitten by blood-sucking bats in a settlement on the coast of the northeastern state of Sucre.

The boys, ages three and 10, were bitten while they slept, and their parents took them to a health center for treatment ''too late''. The minors were already suffering convulsions, fever and limb numbness, said Ninoska Lozada, head of the Health Ministry's regional epidemiology department.

The health authorities have not determined the exact species of bat that bit the children, but Lozada believes it is probably not native to the area. Bats are the most biodiverse mammal species in the country, with more than 150 types.

Rabies is the oldest known animal virus in Sucre, and its mortality rate is ''almost 100 percent,'' said the expert.

HAVANA - Hurricane Ivan's passage through Cuba's Guanahacabibes Peninsula in September left a danger of forest fire, which would be disastrous for the strategic biosphere reserve located there.

Experts warned that a mere spark could be enough to set fire to the great number of trees, branches and leaves that accumulated on the ground as a result of the hurricane's winds on the peninsula, located some 200 km west of Havana.

The forest service corps from the area drew up a program for prevention and surveillance, which includes air patrols and ground clean-up.

Forest service staff will also receive training to fight forest fires, which are normally very rare in the region.

They should be ready by Feb. 1, when the high-risk period begins, says Jesús Cabrera, a forest protection expert.

TEGUCIGALPA - Local officials and residents of the Honduran department of Valle, on the southern border with El Salvador, this month launched a project to save Chisjuyo Bay, in the Gulf of Fonseca.

Soraya Reyes, governor of Valle, told Tierramérica that with funds from the European Union they are working to preserve mangrove forests and marine and land-based nature preserves.

Along the bay there are 32,500 hectares of mangroves and some 40 communities, mostly fishing villages. The project aims to control the use of dynamite in fishing and to protect endangered fish species, said Reyes.

The wetlands system in the area serves as an important regulator of water flow, preventing floods and the salinization of freshwater, said Jorge Varela, of the non-governmental Committee for the Defense and Protection of Flora and Fauna in the Gulf of Fonseca.

GUATEMALA CITY - A technical mission from Taiwan is helping Guatemalan officials in an effort to boost the population of the Petenia splendida, or red bay snook, typical of this country but in danger of extinction from overfishing, officials from the Taiwanese embassy told Tierramérica.

The meat of this fish is particularly tender and tasty, and local demand continues to rise.

The center of snook reproduction is Petén lake, in northern Guatemala, according to the Fund for International Development and Cooperation, overseen by the Guatemalan Foreign Ministry.

The Taiwanese technical experts are helping to set up and finance a new fish hatchery. From March to May, they successfully produced 3,500 fish.

The Taiwanese embassy says the success ''has not only helped overcome the crisis of potential extinction of the fish, but has set a new landmark in the development of fish farming.''