Assessment of subclinical leprosy infection through the measurement of PGL-1 antibody levels in residents of a former leprosy colony in Thailand

Lepr Rev. 2008 Sep;79(3):315-9.


Objectives: 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.

Results: 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.

Conclusions: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Bacterial / blood*
  • Antigens, Bacterial / immunology*
  • Child
  • Child, Preschool
  • Female
  • Glycolipids / immunology*
  • Humans
  • Leper Colonies*
  • Leprosy / diagnosis
  • Leprosy / immunology
  • Leprosy / physiopathology
  • Leprosy / transmission*
  • Male
  • Middle Aged
  • Mycobacterium leprae / immunology
  • Seroepidemiologic Studies
  • Thailand / epidemiology
  • Young Adult


  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Glycolipids
  • phenolic glycolipid I, Mycobacterium leprae