Population survey to determine risk factors for Mycobacterium leprae transmission and infection.
BACKGROUND
Not every leprosy patient is equally effective in transmitting Mycobacterium leprae. We studied the spatial distribution of infection (using seropositivity as a marker) in the population to identify which disease characteristics of leprosy patients are important in transmission.


METHODS
Clinical data and blood samples for anti-M. leprae ELISA were collected during a cross-sectional survey on five Indonesian islands highly endemic for leprosy. A geographic information system (GIS) was used to define contacts of patients. We investigated spatial clustering of patients and seropositive people and used logistic regression to determine risk factors for seropositivity.


RESULTS
Of the 3986 people examined for leprosy, 3271 gave blood. Seroprevalence varied between islands (1.7-8.7%) and correlated significantly with leprosy prevalence. Five clusters of patients and two clusters of seropositives were detected. In multivariate analysis, seropositivity significantly differed by leprosy status, age, sex, and island. Serological status of patients appeared to be the best discriminator of contact groups with higher seroprevalence: contacts of seropositive patients had an adjusted odds ratio (aOR) of 1.75 (95% CI 0.922-3.31). This increased seroprevalence was strongest for contact groups living < or =75 m of two seropositive patients (aOR = 3.07; 95% CI 1.74-5.42).


CONCLUSIONS
In this highly endemic area for leprosy, not only household contacts of seropositive patients, but also people living in the vicinity of a seropositive patient were more likely to harbour antibodies against M. leprae. Through measuring the serological status of patients and using a broader definition of contacts, higher risk groups can be more specifically identified.
Bakker
Mirjam I
MI
KIT (Koninklijk Instituut voor de Tropen/Royal Tropical Institute), KIT Biomedical Research, Amsterdam, The Netherlands.
Hatta
Mochammad
M
Kwenang
Agnes
A
Faber
William R
WR
van Beers
Stella M
SM
Klatser
Paul R
PR
Oskam
Linda
L
D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D002648:Child; D002675:Child, Preschool; D004812:Epidemiologic Methods; D005260:Female; D006306:Health Surveys; D006801:Humans; D007214:Indonesia / Q000453:epidemiology; D007918:Leprosy / Q000453:epidemiology / Q000276:immunology / Q000635:transmission*; D008297:Male; D008875:Middle Aged; D009166:Mycobacterium leprae; D012931:Social Environment
D000907:Antibodies, Bacterial