Two Doses of Azithromycin to Eliminate Trachoma in a Tanzanian Community

Abstract

To the Editor: Single-dose azithromycin is the first-choice antibiotic for the treatment of trachoma. The World Health Organization (WHO) currently recommends annual mass azithromycin treatment for 3 years in communities in which the prevalence of the clinical sign "trachomatous inflammation-follicular" in children between 1 and 9 years of age is 10% or more.We previously reported the effect of high-coverage, single-dose mass azithromycin treatment on ocular Chlamydia trachomatis infection in Kahe Mpya, Tanzania. 1 In all, 97.6% of residents were treated; the prevalence of ocular C. trachomatis fell from 9.5% at baseline to 0.1% 24 months later. We subsequently carried out a second round of mass treatment at 24 months, examined residents at 42 and 60 months, and took conjunctival swabs for testing for C. trachomatis by means of a polymerase-chain-reaction assay at 60 months. Just as at 6, 12, and 18 months, at 42 months, persons with active disease (21 of the 821 residents examined at 42 months) were offered tetracycline eye ointment. Field, laboratory, and statistical methods have been described previously, 1,2 although because we expected the prevalence of infection to be low after the two mass treatments, we combined aliquots from each of five eluted swabs for each assay, intending to retest individual samples if results were positive or equivocal. 3 Approval for the study was obtained from ethics committees at the London School of Hygiene and Tropical Medicine and Tumaini University.At 24 months (when the prevalence of infection was 0.1% 1 ), the rate of antibiotic coverage was 93.1% (917 of 985 persons). At 42 months, 821 of 975 residents (84.2%) were examined, as were 859 of 964 (89.1%) at 60 months. The prevalence of trachomatous inflammation-follicular in children between 1 and 9 years of age fell from 16.3% at 24 months to 4.6% at 42 months and 2.6% at 60 months. At 60 months (3 years after the second mass treatment), C. trachomatis DNA was not detected in the conjunctiva of any of the 859 residents from whom swab specimens were obtained, suggesting that infection may have been eliminated.One or two rounds of high-coverage mass treatment with azithromycin may be sufficient to eliminate ocular C. trachomatis in communities with moderate levels of infection. In this Tanzanian community, the fall in the prevalence of trachomatous inflammation-follicular lagged considerably behind the fall in the prevalence of infection (Fig. 1). Had WHO recommendations on antibiotic use been followed, three or possibly five annual rounds of mass treatment would have been offered, whereas our data suggest that one round was sufficient. A field-based assay for estimating the prevalence of infection 4 is needed to guide treatment decisions in the 3 to 5 years after the first distribution of antibiotics for trachoma control.

Importance of Including Borderline Cases in Trachoma Grader Certification

“…2,3 Individual-and community-randomized clinical trials have typically had clinical exam as primary or secondary outcomes. [4][5][6][7][8][9] Unfortunately, grading of clinical trachoma can have considerable variability. Even with rigorous training, different examiners grade cases differently.…”

Multiplex 5′ Nuclease-Quantitative PCR for Diagnosis of Relapsing Fever in a Large Tanzanian Cohort

“…We sought to identify incidents of symptomatic and asymptomatic relapsing fever as an ancillary study to that of mass treatment with azithromycin for trachoma (Partnership for the Rapid Elimination of Trachoma [PRETϩ]). In the parent study, four villages in the Kongwa district in the central Dodoma region of Tanzania were selected for WHO-recommended single-dose mass treatment with azithromycin (20 mg/kg of body weight, up to 1 g) for highly prevalent (Ն10%) active (trachomatous follicular or intense) trachoma (17,21,25). Within villages, 130 households per village (intervention group) were randomly selected.…”

Tracoma: de lo básico a lo clínico

“…Allí se trató al 97,6 % de los residentes y la prevalencia ocular de la bacteria disminuyó desde 9,5 % a 0,1 % en un período de 24 meses (44). Se ha visto que uno o dos ciclos del tratamiento de alta cobertura con azitromicina en la población pueden ser suficientes para eliminar a C. trachomatis en comunidades con niveles moderados de infección; pese a ello, la OMS sigue recomendando ofrecer de 3 a 5 terapias de tratamiento masivo anuales (44). No se ha informado resistencia de Chlamydia trachomatis a la azitromicina (15,43).…”