Quantitative PCR for leprosy diagnosis and monitoring in household contacts: A follow-up study, 2011-2018

Sci Rep. 2019 Nov 13;9(1):16675. doi: 10.1038/s41598-019-52640-5.

Abstract

Household contacts (HHC) of leprosy patients exhibit high-risk of developing leprosy and contact tracing is helpful for early diagnosis. From 2011 to 2018,2,437 HHC were examined in a clinic in Rio de Janeiro, Brazil and 16S qPCR was used for diagnosis and monitoring of contacts. Fifty-four HHCs were clinically diagnosed with leprosy at intake. Another 25 exhibited leprosy-like skin lesions at intake, 8 of which were confirmed as having leprosy (50% of which were qPCR positive) and 17 of which were diagnosed with other skin diseases (6% qPCR positive). In skin biopsies, qPCR presented a sensitivity of 0.50 and specificity of 0.94. Furthermore, 955 healthy HHCs were followed-up for at least 3 years and skin scrapings were collected from earlobes for qPCR detection. Positive qPCR indicated a non-significant relative risk of 2.52 of developing the disease. During follow-up, those who progressed towards leprosy exhibited 20% qPCR positivity, compared to 9% of those who remained healthy. Disease-free survival rates indicated that age had a significant impact on disease progression, where patients over 60 had a greater chance of developing leprosy [HR = 32.4 (3.6-290.3)]. Contact tracing combined with qPCR may assist in early diagnosis and age is a risk factor for leprosy progression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Brazil / epidemiology
  • Case-Control Studies
  • Child
  • Child, Preschool
  • Cohort Studies
  • Contact Tracing / methods*
  • DNA, Bacterial / analysis*
  • DNA, Ribosomal / analysis*
  • Family Characteristics*
  • Female
  • Follow-Up Studies
  • Humans
  • Infant
  • Leprosy / diagnosis*
  • Leprosy / epidemiology
  • Leprosy / genetics
  • Male
  • Middle Aged
  • Molecular Diagnostic Techniques
  • Mycobacterium leprae / genetics
  • Mycobacterium leprae / isolation & purification*
  • Real-Time Polymerase Chain Reaction / methods*
  • Time Factors
  • Young Adult

Substances

  • DNA, Bacterial
  • DNA, Ribosomal