Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 27, Number 4—April 2021

Epidemiologic and Genomic Reidentification of Yaws, Liberia

Joseph W.S. TimothyComments to Author , Mathew A. Beale, Emerson Rogers, Zeela Zaizay, Katherine E. Halliday, Tarnue Mulbah, Romeo K. Giddings, Stephen L. Walker, Nicholas R. Thomson, Karsor K. Kollie1, Rachel L. Pullan1, and Michael Marks1
Author affiliations: London School of Hygiene and Tropical Medicine, London, UK (J.W.S. Timothy, K.E. Halliday, S.L. Walker, N.R. Thomson, R.L. Pullan, M. Marks); Wellcome Sanger Institute, Hinxton, UK (M.A. Beale, N.R. Thomson); Ministry of Health, Monrovia, Liberia (E. Rogers, Z. Zaizay, T. Mulbah, R.K. Giddings, K.K. Kollie); University College London Hospitals NHS Foundation Trust, London (S.L. Walker, M. Marks)

Main Article


Descriptive epidemiological characteristics of serologically confirmed yaws cases, Liberia*

Total serologically confirmed cases 24
Total PCR-positive lesions 17 (70.8)
Whole genome recovered
12 (50.0)
Prevalence of serologically confirmed yaws, cases/10,000 population (95% CI)
Crude prevalence in survey population 4.2 (2.5–5.9)
Design-adjusted population prevalence
2.6 (1.4–3.9)
Clinical diagnostic accuracy, % (95% CI)
Positive predictive value of all suspected yaws 64.7 (46.5–80.3)
Positive predictive value of yaws ulcers 47.6 (25.7–70.2)
Negative predictive value of tropical ulcers 94.4 (81.3–99.3)
Positive predictive value of yaws papilloma
92.3 (64.0–99.8)
Case demographics
Median age, y(interquartile range)† 10 (8.2–12.0)
M 17 (73.9)
6 (26.1)
Clinical presentation
Ulcer 12 (50.0)
12 (50.0)
No. active lesions‡
1 17 (73.9)
2 3 (13.0)
3 2 (8.7)
1 (4.4)
Patient-reported duration of lesion
<8 wk 9 (37.5)
8–26 wk 6 (25.0)
27 wk–1 y 5 (20.8)
1–3 y 0
>3 y 3 (12.5)
1 (4.2)
Sought formal healthcare for lesion(s)
Yes 11 (45.8)
Provided with any diagnosis from health provider
Yes 1 (4.2)
Treated lesion(s) with prescription pharmaceuticals
Yes 6 (25.0)
Sought traditional medicine for lesion(s)
Yes 2 (8.3)
No 22

*Values are no. (%) except as indicated.
†Missing data for 2 cases.
‡Missing data for 1 case.

Main Article

1These senior authors contributed equally to this article.

Page created: January 13, 2021
Page updated: March 18, 2021
Page reviewed: March 18, 2021
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.