High seropositivity against NDO-LID in a group of household contacts of leprosy patients. Are we close to leprosy elimination in Colombia?

ABSTRACT

Introduction. Leprosy is a chronic infectious disease caused by two mycobacteria (Mycobacterium leprae and Mycobacterium lepromatosis). The household contacts (HHC) of leprosy index cases are at higher risk of being infected with these mycobacteria. Therefore, serological testing in HHC would be an effective strategy to eliminate leprosy in Colombia. Objective: To determine the seroprevalence and factors associated with the infection by M. leprae in HHC. Methods: An observational study was conducted in 428 HHC located in the Colombian Caribbean, Andean, Pacific, and Amazonian regions. We evaluated the seropositivity and titrations of IgM, IgG, and protein A against NDO-LID. Results: The evaluated HHC showed high seropositivity, precisely 36.9% anti-NDO-LID IgM, 28.3% anti-NDO-LID IgG, and 47.7% protein A. Furthermore, Protein A showed a greater capacity to detect infected individuals than other anti-NDO-LID conjugates (p < 0.0001). This study did not show differences in the seropositivity according to sex or age of the HHC (p > 0.05). Higher seropositivity for IgM was evidenced mainly in HHC located in the Colombian Pacific region (p 0.001). This research did not show differences in the seropositivity for these serological tests between HHC of PB or MB leprosy patients (p > 0.05). Conclusion. Leprosy transmission is still active between Colombian HHC. Consequently, controlling leprosy transmission in this population is fundamental to eradicating this disease.

KEYWORDS:

• Public health
• surveillance
• serological tests
• poverty
• disability
• mycobacteria

Acknowledgements

The authors would like to thank the HHC who voluntarily participated in this study and the health personnel of each region studied.

Author contributions

HSC: Clinical evaluation of HHC, data analysis, manuscript writing – original draft preparation, review, and editing.

NCC: Study design, clinical evaluation of HHC, writing – review, and editing.

JB: Evaluation of HHC, serologic evaluation

MM: Serologic evaluation.

All authors read and approved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation, to any qualified researcher.

Informed consent

Written informed consent was obtained from all household contacts before entering the study.

Additional information

Funding

This work was conducted with financial support to Nora Cardona-Castro from Minciencias [grant code 325656933516]. Antigens were produced at IDRI with support from American Leprosy Missions. We confirm the independence of the researchers from the funding sources.