Leprosy among patient contacts: a multilevel study of risk factors.

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TitleLeprosy among patient contacts: a multilevel study of risk factors.
Publication TypeJournal Article
AuthorsSales AM, Ponce de Leon A, Duppre NC, Hacker MA, Nery JAC, Sarno EN, Penna MLF
Abbrev. JournalPLoS Negl Trop Dis
JournalPLoS neglected tropical diseases
Year of Publication2011
Publication Languageeng
KeywordsAdolescent, Adult, Child, Child, Preschool, Contact Tracing, Disease Transmission, Infectious, Female, Humans, Infant, Leprosy, Male, Middle Aged, Mycobacterium leprae, Risk Assessment, Young Adult

BACKGROUND: This study aimed to evaluate the risk factors associated with developing leprosy among the contacts of newly-diagnosed leprosy patients.

METHODOLOGY/PRINCIPAL FINDINGS: A total of 6,158 contacts and 1,201 leprosy patients of the cohort who were diagnosed and treated at the Leprosy Laboratory of Fiocruz from 1987 to 2007 were included. The contact variables analyzed were sex; age; educational and income levels; blood relationship, if any, to the index case; household or non-household relationship; length of time of close association with the index case; receipt of bacillus Calmette-Guérin (BGG) vaccine and presence of BCG scar. Index cases variables included sex, age, educational level, family size, bacillary load, and disability grade. Multilevel logistic regression with random intercept was applied. Among the co-prevalent cases, the leprosy-related variables that remained associated with leprosy included type of household contact, [odds ratio (OR) = 1.33, 95% confidence interval (CI): 1.02, 1.73] and consanguinity with the index case, (OR = 1.89, 95% CI: 1.42-2.51). With respect to the index case variables, the factors associated with leprosy among contacts included up to 4 years of schooling and 4 to 10 years of schooling (OR = 2.72, 95% CI: 1.54-4.79 and 2.40, 95% CI: 1.30-4.42, respectively) and bacillary load, which increased the chance of leprosy among multibacillary contacts for those with a bacillary index of one to three and greater than three (OR = 1.79, 95% CI: 1.19-2.17 and OR: 4.07-95% CI: 2.73, 6.09), respectively. Among incident cases, household exposure was associated with leprosy (OR = 1.96, 95% CI: 1.29-2.98), compared with non-household exposure. Among the index case risk factors, an elevated bacillary load was the only variable associated with leprosy in the contacts.

CONCLUSIONS/SIGNIFICANCE: Biological and social factors appear to be associated with leprosy among co-prevalent cases, whereas the factors related to the infectious load and proximity with the index case were associated with leprosy that appeared in the incident cases during follow-up.

PubMed URL


Link to full texthttp://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0001013
Shelf markSALES 2011a
PubMed Central IDPMC3057944