Finding Yaws among Indigenous People: Lessons from Case Detection Surveys in Luzon and Visayas Island Groups of the Philippines

Abstract

ABSTRACT. Yaws is a chronic, highly contagious skin and bone infection caused by Treponema pallidum subspecies pertenue, usually affecting children in impoverished and remote communities. Yaws lesions have thick yellow crusts on pink papillomas that ulcerate and leave deep scars. Yaws cases were confirmed in the Liguasan Marsh, Mindanao Island group, Southern Philippines, in 2017, but there were no cases confirmed in the Luzon and Visayas Island groups. We aimed to detect at least one active or latent yaws case in the island groups of Luzon and Visayas. Active yaws surveillance was conducted by inviting healthcare providers to report yaws suspects. Five remote villages were included in the case detection surveys: three in Luzon and two in the Visayas Island groups. Two indigenous peoples communities were included: Aetas of Quezon and Dumagat/Remontados of Rizal provinces. Trained field personnel conducted free skin check-ups of children, household contacts, and community members. Yaws suspects underwent point-of-care serologic tests for T. pallidum and nontreponemal antibodies. A total of 239 participants were screened for skin diseases, and 103 had serologic tests. Only the Aetas of Quezon province, Luzon, had confirmed yaws cases. Nineteen cases (54.3%) were detected among 35 Aetas: five active yaws (four children, one adult), two latent yaws (adults), and 12 past yaws (1 child, 11 adults). An 8-year-old boy had yaws with skeletal deformities. We report the first yaws cases among the Aetas of Quezon, Luzon Island group. Active yaws surveillance and case detection in remote areas and among indigenous peoples should continue.