Population-Based Trachoma Mapping in Six Evaluation Units of Papua New Guinea

Abstract

Purpose: We sought to determine the prevalence of trachomatous inflammation – follicular (TF) in children aged 1–9 years, and trachomatous trichiasis (TT) in those aged ≥15 years, in suspected trachoma-endemic areas of Papua New Guinea (PNG). Methods: We carried out six population-based prevalence surveys using the protocol developed as part of the Global Trachoma Mapping Project. Results: A total of 19,013 individuals were sampled for inclusion, with 15,641 (82.3%) consenting to participate. Four evaluation units had prevalences of TF in children ≥10%, above which threshold the World Health Organization (WHO) recommends mass drug administration (MDA) of azithromycin for at least three years; Western Province (South Fly/Daru) 11.2% (95% confidence interval, CI, 6.9–17.0%), Southern Highlands (East) 12.2% (95% CI 9.6–15.0%), Southern Highlands (West) 11.7% (95% CI 8.5–15.3%), and West New Britain 11.4% (95% CI 8.7–13.9%). TF prevalence was 5.0–9.9% in Madang (9.4%, 95% CI 6.1–13.0%) and National Capital District (6.0%. 95% CI 3.2–9.1%) where consideration of a single round of MDA is warranted. Cases of TT were not found outside West New Britain, in which four cases were seen, generating an estimated population-level prevalence of TT in adults of 0.10% (95% CI 0.00–0.40%) for West New Britain, below the WHO elimination threshold of 0.2% of those aged ≥15 years. Conclusion: Trachoma is a public health issue in PNG. However, other than in West New Britain, there are few data to support the idea that trachoma is a cause of blindness in PNG. Further research is needed to understand the stimulus for the active trachoma phenotype in these populations.

Prevalence of trachoma in Yemen: results of population-based prevalence surveys of 42 evaluation units in nine governorates

“…We found that younger children had lower odds of TF. This finding contrasts with that of many other studies, 19,21,26,27 where the burden of TF is typically found in pre-school childrenthe age group shown to harbor the bulk of the ocular C. trachomatis reservoir in environments in which this has been studied in detail. 28,29 A shift of the burden of TF to higher age groups has been noted in areas where trachoma has lower overall prevalence, presumably because intensity of transmission (and age of first exposure) is lower in these areas.…”

The Epidemiology of Trachoma in Mozambique: Results of 96 Population-Based Prevalence Surveys

“…This is in keeping with the belief that younger children act as the reservoir of infection for ocular C. trachomatis, 16 and that close contact with more children is likely to facilitate spread.- [17][18][19][20] In addition, we found that unimproved latrine facilities, or living in a household with no latrine facilities, was an independent association of TF in children. Similar associations have been noted elsewhere, both prior to [21][22][23][24] and within the GTMP, 20,[25][26][27] and are in keeping with the belief that latrine facilities of a given standard limit the reproductive potential of the flies associated with transmission. 5,28,29 At larger scale, it is noted that active trachoma exists as a public health problem in Mozambique in an arc of endemicity stretching from Cabo Delgado in the country's north-east to Tete in the west.…”

Ocular Chlamydia trachomatis infection, anti-Pgp3 antibodies and conjunctival scarring in Vanuatu and Tarawa, Kiribati before antibiotic treatment for trachoma

“…Data from the Solomon Islands, 12 Vanuatu 13 and Papua New Guinea 14 have shown the epidemiology of trachoma in Melanesia to be unusual in that TT is rare or absent despite a moderate prevalence of TF. In contrast, in Kiribati, both TF and TT exceed the prevalence threshold for trachoma to be considered a public health problem.…”