A single population-wide dose of antibiotic can virtually eliminate the blinding disease trachoma, a study said on Wednesday, although other researchers warned high levels of infection could hinder the drugs’ success.

Trachoma, an infectious disease caused by a form of the bacterium Chlamydia, is found mostly in places with poor hygiene and affects about 84 million people in 55 countries, according to Silvio Mariotti of the World Health Organization in Geneva.

In about 7.6 million of those sufferers, the illness has caused the eyelashes to turn inward, the constant rubbing of which against the cornea can in time lead to blindness.

But a study published in Thursday’s edition of The New England Journal of Medicine showed that antibiotic treatment can almost eliminate the ailment.

A team led by Anthony Solomon of the London School of Hygiene and Tropical Medicine gave the antibiotic azithromycin to nearly all of the 978 residents of a village in Tanzania.

People with active disease periodically received antibiotic eye ointment as well.

At the beginning of the study, 9.5 percent of the population, or 95 people, had the infection. Two years later, only 1 person out of 842 tested was still infected.

“The prevalence and intensity of infection fell dramatically and remained low for two years after treatment,” the Solomon team concluded.

But in an editorial in the Journal, Mariotti cautioned that the technique may not work in others areas with trachoma.

In some communities, Mariotti said, the infection rate may be as high as 80 percent and it could be difficult to get so many people to take the antibiotic at the same time.

The researchers also acknowledged that improvements in hygiene might have contributed to the result.

Furthermore, past attempts to use antibiotics to wipe out the disease have produced mixed results and such treatments can be expensive and hard to administer in developing countries.