Six different rapid diagnostic tests have proved reliable in detecting Chagas disease without having to wait for laboratory confirmation, according to a study by the medical charity Doctors Without Borders and the World Health Organization.

Such quick tests could be a breakthrough for controlling the disease, which infects up to eight million people in Latin America and has spread, through migration, to the United States, Europe, Asia and the Western Pacific. Chagas is caused by a parasite normally passed on by the bite of the kissing bug, also known as the reduviid bug or the triatomine bug. It has also been transmitted by blood and organ donations, to fetuses by mothers and, in rare cases, through food with crushed bugs in it.

It may begin with a mild infection but prove fatal decades later when a weakened organ — usually the heart, esophagus or bowel — suddenly collapses. It kills about 12,000 people a year, according to the W.H.O.

The earlier treatment with antiparasitic drugs starts, the better the outcome usually is.

Tests on 474 blood samples by multiple laboratories showed that six of 11 tests that gave results in 30 minutes or less were very reliable. Tests to see how well they work in the field with blood obtained by finger prick are now underway.