British Leprosy Relief Association
Assessment of subclinical leprosy infection through the measurement of PGL-1 antibody levels in residents of a former leprosy colony in Thailand
aRaj Pracha Samasai Institute, Department of Disease Control, Tiwanon Road, Muang District, Nonthaburi 11000, Thailand
Correspondence to: K. Kampirapap, Institute of Dermatology, 420/7 Rajvithi Road, Phyathai, Bangkok 10400, Thailand (Tel: +668 2354 8040; e-mail: email@example.com)
To investigate the hypothesis that there is continuing subclinical M. leprae infection, contributing to ongoing transmission of leprosy in Phra-Pradaeng Colony. Design A sero-epidemiological survey was carried out in Phra-Pradaeng Colony, Thailand between May and August 2005. The clinical and serological examinations were conducted in 398 people, aged 3–84 years (average 50 years), comprising 196 males and 202 females.
Measurement of serum anti PGL-I antibodies in eligible contacts and ex-patients showed that 18 people (4.5%) were seropositive, six people (1.5%) were strongly positive and 374 people (94.0%) were seronegative. All six people who were strongly seropositive were ex-patients; five of them had no evidence of active leprosy but the sixth person had relapsed BL leprosy with a reversal reaction.
This study failed to confirm the hypothesis that there was ongoing subclinical M. leprae infection. More appropriate diagnostic methods and a total survey of the colony should be considered to further clarify this problem.