An international medical research team led by UCSF has found that a proposed single-dose antibiotic strategy to treat the world's leading preventable cause of blindness is inadequate. Follow-up antibiotic treatments are needed, since the infection known as trachoma slowly returns over two years, the team discovered.
The World Health Organization (WHO) has recommended communitywide antibiotic distributions as part of its strategy to eliminate trachoma by the year 2020. Current WHO guidelines recommend three annual mass distributions of antibiotic, but some researchers have suggested that where trachoma prevalence is high, a single treatment might eliminate the disease.
The new research in eight Ethiopian villages found that while a single treatment with the antibiotic azithromycin dramatically reduced infection in children aged 1 to 5 years from 44 percent to 5 percent, infection rates then increased over the next two years to about 11 percent.
Twice-yearly antibiotic treatments, on the other hand, promise to eliminate infection within a few years, said Thomas Lietman, MD, senior author of the study published this week in the Journal of the American Medical Association (JAMA). The article is posted
here.
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| Thomas Lietman |
"It was probably too hopeful to expect that a single distribution would eliminate infection, but the results are still encouraging," Lietman said. "The WHO protocol of three repeat treatments appears to be on the right track. We predict that biannual treatments for three years may eliminate infection from many of the most infected villages."
Lietman is associate professor of ophthalmology and of epidemiology and biostatistics in the Francis I. Proctor Foundation for Research in Ophthalmology at UCSF.
Trachoma is caused by a strain of bacteria called Chlamydia trachomatis. It is spread to the eyes from fingers, clothing or perhaps face flies. Although the highest rates of infection are among children, the blindness develops through repeated infection and scarring inside the eyelid.
The bacterium is related to the microbe that causes genital chlamydia, but is a slightly different strain and is not sexually transmitted, Lietman said.
The research brought together expertise of UCSF medical scientists in ophthalmology with colleagues at Orbis International in Ethiopia, the Aravind Eye Hospital in India and the California Department of Health Services.
The study is part of a five-year research effort led by the Proctor Foundation and funded by the Bernard Osher Foundation, That Man May See, the Harper Inglis Trust and other groups to determine whether a bacterial disease can be eliminated with mass distributions of antibiotics. If successful, the strategy may be applied to other bacterial diseases.
The Proctor Foundation for Research in Ophthalmology is an organized research unit at UCSF focusing on preventing infectious and inflammatory diseases of the eye through research, education and treatment.
Source: Wallace Ravven, UCSF News Services
Links:
Effect of a Single Mass Antibiotic Distribution on the Prevalence of Infectious Trachoma
