Yaws recurrence in children at continued risk of infection

Author summaryYaws is a neglected tropical disease produced by Treponema pallidum pertenue that causes skin ulcers in children living in remote rural areas of the South Pacific and West Africa. Children aged 5-15 and individuals with a history of recurrence are at higher risk of reinfection. Although yaws can be treated with single-dose azithromycin, some children present with recurrent cutaneous ulcers; however, the prevalence and risk factors for yaws recurrence are poorly known. Our analysis of skin ulcers in Papua New Guinea revealed that up to 20% of patients who presented to a health care facility in the Lihir island of Papua New Guinea with a cutaneous ulcer experienced a recurrent episode within the 6-36 months following treatment. Nearly all individuals with recurrent yaws were children aged 15 years or younger. Besides age, the number of previous ulcers was associated with a higher risk of recurrence. The molecular analysis revealed that among cases with T. pallidum at baseline that had a recurrence, this was often related to reinfection with the same microorganism. Our results confirm the need for active follow-up of young children diagnosed with cutaneous ulcers, with particular attention to those with younger age and previous history of recurrences. BackgroundIn yaws-endemic areas, children with Treponema pallidum subsp. pertenue infection may suffer recurrent episodes due to either reinfection or relapse. However, the possibility of infection with other cutaneous ulcer causative agents and difficulties in interpreting standard laboratory results challenges the estimation of yaws recurrence rates. MethodsWe estimated the rates of yaws recurrences in the Lihir Island (Papua New Guinea) using two approaches: passive surveillance based on a retrospective screening of electronic medical records of cutaneous ulcers diagnosed using serological testing between 2005 and 2016, and active surveillance conducted during a cross-sectional prevalence study which included PCR analyses of ulcers of all suspected cases of yaws. The risk of recurrent infection was assessed based on data from the passive surveillance analysis and using two Cox regression models (crude and multivariate), stratified by year of index episode. Data gathered from the active surveillance was used to characterize the recurrences and no hypothesis testing was performed. ResultsThe electronic medical records included 6,125 patients (7,889 ulcer episodes) with documented serological results of cutaneous ulcers of which1,486 were diagnosed with yaws. Overall, 1,246/6,125 patients (20.3%) presented more than once with a cutaneous ulcer, and 103/1,486 (6.7%) patients had multiple episodes of yaws. The risk of yaws recurrence significantly increased with age and was higher in patients with >= 3 recurrent episodes. In the active surveillance, we identified 50 individuals with recurrent cutaneous ulcer that had PCR results available for both the index and recurrent episode. Of 12 individuals with T. pallidum in the index ulcer, 8 (66%) had T. pallidum in subsequent assessments, relapse related to macrolide-resistance was identified in two of these cases. ConclusionsOur results confirm the need for active follow-up of yaws patients after treatment, particularly children and individuals with a history of recurrence.

Automated summary

Recurrent episodes of Yaws can occur in children living in remote rural areas, with a higher risk for those aged 15 or younger. The number of previous ulcers and reinfection with the same microorganism are associated with a higher risk of recurrence. Active follow-up is necessary for young children diagnosed with cutaneous ulcers, especially those with a history of recurrence.