High burden and seasonal variation of paediatric scabies and pyoderma prevalence in The Gambia: A cross-sectional study

Abstract

Background

Scabies is a WHO neglected tropical disease common in children in low- and middle-income countries. Excoriation of scabies lesions can lead to secondary pyoderma infection, most commonly by Staphyloccocus aureus and Streptococcus pyogenes (group A streptococcus, GAS), with the latter linked to acute post-streptococcal glomerulonephritis (APSGN) and potentially rheumatic heart disease (RHD). There is a paucity of data on the prevalence of these skin infections and their bacterial aetiology from Africa.

Methodology/Principal findings

A cross-sectional study, conducted over a four-month period that included the dry and rainy season, was conducted to determine the prevalence of common skin infections in Sukuta, a peri-urban settlement in western Gambia, in children <5 years. Swabs from pyoderma lesions were cultured for S. aureus and GAS. Of 1441 children examined, 15.9% had scabies (95% CI 12.2–20.4), 17.4% had pyoderma (95% CI 10.4–27.7) and 9.7% had fungal infections (95% CI 6.6–14.0). Scabies was significantly associated with pyoderma (aOR 2.74, 95% CI 1.61–4.67). Of 250 pyoderma swabs, 80.8% were culture-positive for S. aureus, and 50.8% for GAS. Participants examined after the first rains were significantly more likely to have pyoderma than those examined before (aRR 2.42, 95% CI 1.38–4.23), whereas no difference in scabies prevalence was seen (aRR 1.08, 95% CI 0.70–1.67). Swab positivity was not affected by the season.

Conclusions/Significance

High prevalence of scabies and pyoderma were observed. Pyoderma increased significantly during the rainy season. Given the high prevalence of GAS pyoderma among children, further research on the association with RHD in West Africa is warranted.

Author summary

Scabies is a WHO neglected tropical disease which is common in low- and middle-income countries with tropical climates, which can lead to serious compilations via secondary bacterial infection of skin lesions. Group A streptococcal skin infection is known to cause kidney disease, but may also contribute to rheumatic heart disease. Despite this, little is known about the prevalence of common paediatric skin infections in sub-Saharan Africa, or which bacteria most commonly cause skin infections. We conducted a cross-sectional study of skin infections in The Gambia into the prevalence of scabies, pyoderma and fungal infections in children <5 years. We examined 1441 children and found a scabies, pyoderma and fungal infection prevalence of 15.9%, 17.4% and 9.7% respectively, with significantly increased presence of bacterial skin infections in the rainy season. Over half of bacterial skin infections were found to be positive for group A streptococcus. Our study shows that scabies and pyoderma occur commonly in young children in The Gambia, representing a significant exposure to group A streptococcus at a young age, and that there is a strong seasonal effect on pyoderma, which may have implications for treatment strategies.