Factors associated with new leprosy diagnosis in Kwale County, Kenya

Leprosy, a chronic bacterial disease caused by Mycobacterium leprae, is
curable yet neglected. Approximately 200,000 new cases are reported
globally each year, with India contributing 60%. In 2020, the African WHO
regions had a leprosy burden of 14.9 per 1,000,000 population. Despite
maintaining the global elimination target of <1/10000 population,
Kenya reported a six-fold increase in cases(63-163) from 2011 to 2021,
with Kwale County contributing 24.3%. This study aimed to determine the
factors associated with new leprosy diagnoses. We conducted a 1:3
case-control study in the Kwale from June to September 2023. Cases
included people who were treated for leprosy based on clinical/laboratory
and epidemiological criteria between January 2022 and May 2023. Controls
were persons with no signs or symptoms and were a neighboring household to
a case in another or nearby plot, matched by sex, age group of ±10 years,
and village. Questionnaires were administered to both groups. Factors
associated with Leprosy were evaluated using multivariable logistic
regression. Stepwise backward elimination was used to build a final model;
p-values of ≤0.05 were considered significant. A total of 65 cases and 195
controls were enrolled. The mean age was 55 years (SD±16) for the cases
and 54 years (SD±15) for the controls. Among cases,56.6% (n=37) were
married, compared to 71.1% (n=139) of controls. 55% (n=36) of the cases
and 41% (n=81) of the controls were illiterate. The odds of being
diagnosed with leprosy were seven times higher among patients with a
family size ≥5 members (aOR=6.99, 95% CI: 2.71–18.06) and four times
higher among those with a family contact (aOR=4.33, 95% CI: 2.18–8.58).
Social contact (aOR=2.24,95% CI: 1.16–4.32) and non-vaccination with BCG
(aOR=2.24,95% CI: 1.11–4.53) are associated with double odds of new
leprosy diagnosis. Leprosy prevention efforts in high-burden counties
should prioritize early detection, prompt treatment of cases, enhanced
community-based surveillance, and household contact tracing to reduce
transmission. In addition, the Ministry of Health should sustain and
expand the BCG vaccination coverage among all eligible persons.