Investigation of human tungiasis cases, Sheema District, Uganda, November 2021-February 2022

Abstract

Introduction: no formal surveillance system exists in Uganda for jiggers (tungiasis); however, outbreaks are frequently reported in the media. On 27^th January 2022, a news alert reported a jiggers’ outbreak in Sheema District, Southwestern Uganda. We investigated to establish the magnitude of the problem and identify possible exposures associated with infestation to inform control measures.

Methods: we defined a confirmed case as visible Tunga penetrans in the skin of a resident of any of 6 villages in Bwayegamba Parish, Sheema District, in February 2022. A suspected case was self-reported T. penetrans infestation during the three months preceding the interview. We visited all households in the 3 most affected villages in Bwayegamba Parish to identify cases and conducted interviews to identify possible exposures. We described cases by person, place, and time. We assessed socioeconomic status, household construction, mitigation measures against jiggers, and observed participants and their environments for hygiene. We conducted 2 case-control studies. One compared case-households (with ≥1 case) with control-households (without any cases). The second compared individual cases (suspected and confirmed) to neighbourhood controls.

Results: among 278 households, we identified 60 case-patients, among whom 34 (57%) were male. Kiyungu West was the most affected village (attack rate=31/1,000). Cases had higher odds of being male (ORMH=2.3, 95% CI=1.3-4.0), <20 years of age (ORMH=2.0, 95%CI=1.1-3.6), unmarried (ORMH=2.97, 95% CI=1.7-5.2), unemployed (ORMH=3.28, 95% CI=1.8-5.8), and having poor personal hygiene (ORMH=3.73, 95% CI=2.0-7.4) than controls. In the household case-control study, case-households had higher odds of having dirty or littered compounds (ORMH=2.3, 95% CI=1.2-4.6) and lower odds of practicing mitigation measures against jiggers (ORMH=0.33, 95% CI=0.1-0.8) than control-households.

Conclusion: males, unemployed persons, and those with poor personal or household hygiene had increased odds of tungiasis in this outbreak. Multi-sectoral, tailored interventions that improve standards of living could reduce risk of tungiasis in this area. Adding tungiasis to national surveillance reporting tools could facilitate early identification of future outbreaks.