Disease, Unwanted Import

Contagious diseases are entering the United States because of immigrants, illegal aliens, refugees and travelers, and World Health Organization officials say the worst could be yet to come.

In addition to a list of imported diseases that includes tuberculosis, sickle cell anemia, hepatitis B, measles and the potentially deadly parasitic disease Chagas, officials fear what could happen if the avian flu, which is flourishing among poultry in Southeast Asia, mutates so that it is capable of human-to-human transmission through casual contact.

The bird flu has killed at least eight Asians since early January. Several of those deaths — in Vietnam and Thailand — were believed to have been caused when the virus passed between people who had sustained contact. If the avian flu mutates so that it can be transmitted with only casual contact, WHO authorities predict at least 7 million and as many as 100 million would die in a worldwide pandemic.

Another concern with Asian immigrants in this country is the link between Asians and hepatitis B, said Jordan Su, program manager for the Asian Liver Center at Stanford University. She said the link is alarming enough to warrant action on its own.

Hepatitis B is a “very common epidemic in Asia” and more than half of the 1.3 million cases in this country are among Asians, who make up only 4 percent of the U.S. population, she said.

“We hope the government will pass a bill that requires every immigrant to be tested for hepatitis B,” Ms. Su said.

“People, in general, bring in diseases from their home countries. But I don’t want to say all immigrants are carrying diseases,” said Dr. Walter Tsou, president of the American Public Health Association.

Dr. Kenneth Castro, director of the Division of TB Elimination at the Centers for Disease Control and Prevention in Atlanta, said the job of preventing these diseases must extend beyond the United States.

“Many diseases know no borders, but all policies to prevent the importation of disease need to be reasonable and implementable, and our efforts to improve disease control cannot be restricted to our borders,” he said.

Concerns about imported disease prompted the State Department on Jan. 21 to temporarily suspend travel to this country by Hmong refugees from the Wat Tham Krabok camp in Thailand. The order came after federal health officials learned of at least 25 confirmed cases of TB among refugees from that camp who had resettled in California, Wisconsin and Minnesota.

Enhanced medical screening and treatment of the refugees are under way both in Thailand and this country, and State Department officials say it could be six months before the travel ban is lifted.

TB a growing threat

According to international health officials, about a third of the world’s population is infected with the bacteria that cause tuberculosis. TB that is resistant to multiple drugs is rampant in many parts of the world, including Peru, Russia, the Baltic nations, Hunan province in China, the Dominican Republic and parts of South Africa, according to Dr. Castro. Some of the cases of TB diagnosed among Hmong refugees resettled in this country are drug-resistant, which makes them far more difficult and costly to treat.

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