CARACAS, Dec 26 (Tierramérica) - The West Nile virus has been reported in Venezuela, north of the Orinoco River, likely carried into the country by migratory birds, researcher Juan Carlos Navarro, of Venezuela's Central University, told Tierramérica.

The microorganism has been spreading from north to south in the Americas, and can be found in the United States, Mexico, Central America, the Antilles and Colombia.

First detected in Uganda in 1937, the virus is transmitted by mosquitoes and ticks, and affects birds and mammals. In humans it causes fever and can lead to encephalitis, and in some cases, death.

"An epidemic of West Nile virus is unlikely in Latin America because most of the population has faced dengue or was vaccinated against yellow fever, but we must remain vigilant because the virus can mutate and affect people who were considered protected," said Navarro.

SAO PAULO, Dec 26 (Tierramérica) - Less than seven percent of the Brazilian coastal forest ecosystem, the Mata Atlantica, remains intact, compared to its area in 1500, according to a study by the SOS Mata Atlantica Foundation and the National Institute of Space Research.

The areas that saw the most deforestation since 2000 are concentrated in the more economically and socially developed states of the southern Mata, which extended across 1.36 million square kilometers, or about 15 percent of Brazilian territory.

"We invite the public to learn about the state of this biome. Data and maps are available at the portal www.sosma.org.br," Marcia Hirota, director of SOS Mata Atlantica, told Tierramérica.

The first atlas of the remaining forest dates back to 1990. Since then, there has been a greater public mobilization in defense of the Mata, and Congress recently passed a law to protect the ecosystem -- after 14 years.

SANTIAGO, Dec 26 (Tierramérica) - More than 3,200 milligrams of lead per kilogram of soil has been found in the area around the northern Chilean town of Portezuelo, 14 km southeast of Antofagasta, where there is a lead storage site.

"The site should be closed up, and the trucks that transport the lead (to the port of Antofagasta) should be sealed," Hugo Benítez, president of the region's medical school, told Tierramérica.

The health authorities have pledged to seek solutions, given that high concentrations of lead can cause cancer, neurological damage, attention deficit and aggressive behavior, especially in children.

HAVANA, Dec 26 (Tierramérica) - Cuban farmers are worried about excessive rains, blamed on the climate phenomenon known as El Niño-Southern Oscillation (ENSO), that continued to fall across this island nation in December.

"Rain is a good thing, but not this much. The soil is too wet for the winter planting," and there is greater risk of mold on the crops, Rubén Torres, a farmer outside the city of Santa Clara, 268 km east of Havana, told Tierramérica.

ENSO will trigger heavier rains and storms between January and April, warns a report from the climate center at the Cuban Institute of Meteorology.

The phenomenon involves a five-month temperature hike of half a degree Celsius of the surface waters of the western, central and eastern Pacific Ocean. The most devastating El Niño, in 1993, is blamed for economic losses of more than a billion dollars.

BUENOS AIRES, Dec 26 (Tierramérica) - Students and professors from the National University of La Pampa, in central Argentina, are beginning a census this month of peasant farming families threatened with eviction in five departments of La Pampa province.

The study is an effort to halt the removal of some 300 families of subsistence farmers who have occupied lands, with no title, for more than 20 years.

Private title-holders are reclaiming possession of some of these areas, where minerals and petroleum have been found in recent years.

"The government is delaying solutions, and our preliminary surveys show, for example, that in just one site there are 17 oil wells," Claudia Salomón, of the Support Movements for the Land Struggle, told Tierramérica.