GENEVA, April 13 (Reuters) - Chagas, a parasitic disease which can kill victims decades after infection, has spread from Latin America to the United States and Europe due to inadequate blood screening, the World Health Organisation said on Friday. The United Nations agency said it was expanding its programme to eliminate Chagas, which has become a "global problem", with the help of Bayer HealthCare <BAYG.DE>. Bayer's donation of 2.5 million tablets of Lampit, known generically as nifurtimox, will help treat an estimated 30,000 patients over the next five years, covering new acute cases among youngsters, it said. Chagas, which currently affects an estimated nine million people, mainly children in rural areas of Latin America, has emerged in the United States, Spain and several other European countries after large-scale migrations, the WHO said. No exact death toll exists for the "silent killer" which causes the slow swelling of victims' internal organs, resulting in their eventual death, according to the WHO. Most victims may not know they have contracted Chagas as the infection may remain dormant for decades after they have been bitten by a blood-sucking insect similar to a large bed bug which transmits the parasite. "This disease still poses a threat to so many people in Latin America and now that threat has spread to other countries via blood banks lacking adequate screening of infected donors," said Mirta Roses Periago, WHO director for the Americas region. The Geneva-based WHO has been working to wipe out the disease and the number of those infected has fallen from 16-18 million people in 1990. Transmission of the disease has been interrupted in Chile, Uruguay, a large part of Brazil, as well as vast areas of Central America, Argentina, Bolivia and Paraguay, the WHO said. The most endemic regions remain the Chaco regions of Bolivia and Argentina, as well as parts of Mexico, Peru and Colombia, according to Jannin.
