Health experts have recently reported a small, but dangerous increase in tuberculosis infections that are resistant to antibiotics. The Centers for Disease Control and Prevention announced the presence of 128 cases of tuberculosis in the U.S. in 2004 resistant to drugs, an increase of 113 cases since last year. Of these 128 cases discovered, 97 were in people born abroad. One of the cities with the highest rates of tuberculosis, because of so many foreign-born residents, experienced a decrease of the number of infections with tuberculosis to 989, below 1,000 for the first time. Drug-resistant strains of the disease have been found in immigrants from many countries, among which China, India, Mexico, Vietnam, the Philippines, Ecuador, the Dominican Republic and Haiti. The number of cases hard to treat, "extensively drug resistant", rose from 3.9 percent in the 1993-1996 to 4.5 percent during 2001-2004. The survey, made by the Centers for Disease Control and Prevention and the World Health Organization, which took into consideration research of 25 tuberculosis laboratories on six continents from 2000 to 2004, found that 1 in 50 cases of the disease is resistant not only to primary drugs, but also to those which represent the second line of defense, more toxic and less effective. Doctors believe that tuberculosis got its resistance because some patients did not complete a full course of medication. "Drug-resistant TB is growing, and that should worry us," said Marcos Espinal, a World Health Organization official. There are some drugs under development for these new types of tuberculosis, but funding has prevented researchers from further tests.