Eye Protection: Antibiotic knocks back blinding disease

Medicating an entire village twice a year can hamper a scourge that has blinded millions of people in developing countries, a study in Ethiopia shows.

The bacterial eye disease trachoma was wiped out in the United States and much of the industrialized world around the mid-20th century, thanks to improved hygiene, sanitation, and antibiotics. But the disease remains a problem in parts of Africa and Asia.

Trachoma often begins as minor itching called pinkeye. But repeated infections cause scarring of the inner eyelid. As the lids curl in, eyelashes rake the cornea, clouding it and leading to blindness.

In the new study, researchers targeted 16 villages in the impoverished Gurage region of Ethiopia where trachoma is rife. They used eyelid swabs to diagnose infections among preschool-aged children. After recording the infection rate, the scientists distributed the oral antibiotic azithromycin to everyone over 1 year of age. People in half the villages received a single annual dose while those in the others received a similar dose every 6 months.

After 2 years, the trachoma rate among preschoolers treated once annually had dropped from 43 percent to 7 percent. In villages where people got two doses a year, the rate plummeted even further—from 32 percent to less than 1 percent. The findings appear in the Feb. 20 Journal of the American Medical Association.

The bacterium Chlamydia trachomatis spreads by personal contact, sharing of towels, failure to wash the hands and face, and by flies and gnats. Preschoolers often carry high bacteria loads, making them efficient conveyors of infection.

Gurage is a hilly land of small villages, rough roads, and poor sanitation. Most residents live on subsistence farming. Women must often carry clean water several kilometers to keep their families supplied, says study coauthor Jenafir House, a public health researcher at the University of California, San Francisco. As a result, hygiene suffers. Moreover, because much of Gurage is more than 7,000 feet above sea level, warm water for washing is scarce. Heating it means competing for fuel, she says.

Despite the promising findings, public health officials don’t agree on the best way to control trachoma. Mass medication “is a stopgap measure,” says Ibrahim Jabr, president of the International Trachoma Initiative in New York City, which partly funded this research. “I have great respect for this study,” he says. But long-term control can’t be established without access to clean water, education about hygiene, and improved living conditions, he says. “For that you need mega-investment.” Morocco wiped out trachoma in recent years using this combination plus medication, he says.

However, such improvements are difficult to achieve without broad economic gains, says David Mabey, an infectious disease physician at the London School of Hygiene & Tropical Medicine. In the meantime, knocking out infections with antibiotics has greatly reduced—though not eliminated—the disease in Gambia (SN: 9/25/99, p. 203) and Nepal, he says. Fortunately, C. trachomatis doesn’t show signs of becoming antibiotic resistant.