Friday, October 7, 2011

Serious Latin American disease is more common in Texas than thought

Austin American Statesman:
http://www.statesman.com/news/local/serious-latin-american-disease-is-more-common-in-1900225.html

A blood-sucking insect that claims thousands of lives in Latin America each year is believed to be a greater threat in Texas than previously thought and has killed dogs and possibly some people in the state, a state health official and University of Texas researcher said this week.

They don't know how many people have been exposed to Chagas disease or might have it because doctors are not required to report the illness to health departments. But state health department official Jim Schuermann and UT researcher Sahotra Sarkar want to change that and hope to make Central Texas doctors aware of the illness.

Central and South Texas are the two highest-risk areas in the state for Chagas, according to Sarkar, a professor of integrative biology and philosophy who has been studying the disease for five years.

"It's nothing people need to panic about," said Schuermann, staff epidemiologist for vector-borne and zoonotic diseases at the Department of State Health Services. "It's not like hundreds of people are dying" in Texas.

Schuermann said he will soon ask the board that oversees the state health department, the State Health Services Council, to require reporting of Chagas. It could take six to eight months for the council to make a ruling, he said.

Chagas disease can sneak up on people like its carriers, the triatomine insects — also called "assassin bugs" or "kissing bugs" — do when they infect mammals, birds and reptiles. The bugs, which are infected from biting rodents or other animals with Chagas, are nocturnal parasites that nest in brush piles, dog houses, rodent nests, chicken coops and cracks in substandard housing. They typically infect humans by biting around the mouth or eyes to suck blood while the person sleeps. The bugs leave infectious feces behind that get rubbed into the person.

The bite can cause an allergic reaction characterized by severe redness, itching, swelling, hives, or, rarely, anaphylactic shock, according to the U.S. Centers for Disease Control and Prevention.

Usually, the person recovers after experiencing flu-like symptoms that can include nausea and vomiting, rash and swollen glands. But without treatment, the infection can be lifelong. The CDC said that in 20 to 30 percent of cases, the disease can reappear a decade or two later as difficulty swallowing because of an enlarged esophagus, abdominal pain because of an enlarged colon, or heart disease, including congestive heart failure or sudden cardiac arrest.

"How many heart attacks are Chagas? We really have no way of knowing," Schuermann said. "It is a leading cause of heart disease in Central America."

A blood test can tell whether a person or animal has Chagas, Schuermann said.

"Dogs can look perfectly healthy, and they'll be running around and just die," he said. Some veterinarians send the blood for testing to a lab, such as Texas Veterinary Medical Diagnostic Laboratory, which is part of Texas A&M University and can detect Chagas.

The disease can be transmitted from person-to-person by blood transfusions, from mother to child and by transplants. Between 75 and 90 percent of the U.S. blood supply is tested for it, Schuermann said. The Blood and Tissue Center of Central Texas has been testing for Chagas since 2007, spokeswoman Andrea Lloyd said.

The kissing bug is found routinely in Central Texas, and "we are lucky we are not getting more of the transmission here," Sarkar said.

Half of the kissing bugs they've found are infected, he said, and that has raised the worry. A news release Thursday from Doctors Without Borders said that thousands of Latin Americans with Chagas will go untreated because of a shortage of benznidazole, the first-line drug that's used. The organization said up to 10 million people worldwide are infected with Chagas, and 12,500 die each year.

Sarkar was a lead author of a paper published a year ago in the journal Public Library of Science Neglected Tropical Disease that argued that the infection risk in Texas was high enough to warrant required reporting, as Arizona and Massachusetts do.

Because the disease is so little known in the United States, just seven cases have been confirmed nationally, including four in Texas and one each in California, Tennessee and Louisiana, the paper said. However, it said that one research group's estimate that 300,167 Americans might be infected is credible.

maroser@statesman.com; 445-3619