Genotyping of Mycobacterium leprae for understanding the distribution and transmission of leprosy in endemic provinces of China

Abstract

Understanding the nature of Mycobacterium leprae transmission is vital to implement better control strategies for leprosy elimination. The present study expands the knowledge of county-level strain diversity, distribution, and transmission patterns of leprosy in endemic provinces of China. Methods: We genetically characterized 290 clinical isolates of M. leprae from four endemic provinces using variable number tandem repeats (VNTR) and single nucleotide polymorphisms (SNPs). Attained genetic profiles and cluster consequences were contrasted with geographical and migration features of leprosy at county levels. Results: Considering the allelic variability of 17 VNTR loci by the discriminatory index, (GTA)9, (AT)17, (AT) 15, (TA)18, (TTC)21, and (TA)10 are reported to be more highly polymorphic than other loci. The VNTR profile generated the low-density clustering pattern in the counties of Sichuan and Yunnan, whereas clusters have been observed from the isolates from Huayuan (N = 6), Yongding (N = 3), Zixing (N = 3), Chenxi (N = 2) and Zhongfang (N = 2) counties of Hunan, and Zhijin (N = 3), Anlong (N = 2), Zhenning (N = 2), and Xixiu (N = 2) counties of Guizhou. In some clusters, people's social relations have been observed between villages. From the 290 clinical isolates, the most predominantly reported SNP was 3K (278, 95.8%), followed by SNP 1D (10, 3.4%), which are typically observed to be predominant in China. We also detected the novel SNP 3J (2, 0.8%), which has not yet been reported in China. Conclusion:The clustering pattern of M. leprae indicates the transmission of leprosy still persists at county levels, suggesting that there is a need to implement better approaches for tracing the close contacts of leprosy patients.

Leprosy Update in China, 2019

“…Considering the proportion had fluctuated from 18.6% to 28.7% between 2010 and 2019, several innovative strategies should be implemented to strengthen the ability to achieve early detection, early diagnosis, and early treatment to avoid the development of disability. [21][22] In addition to leprosy detection using advanced laboratory methods such as molecular 23 or serological techniques, [24][25] another method is symptom-driven case detection. This method has been implemented nationwide since 2019, and encourages grassroots health workers to refer any patients with symptoms indicative of leprosy to the nearest dermatology clinic or local leprosy control unit for further clinical examination and diagnosis.…”

Predictive nomogram for leprosy using genetic and epidemiological risk factors in Southwestern China: Case–control and prospective analyses

“…According to the official WHO records, a total of 208641 new leprosy patients were reported globally in 2018, China contributed 521 (0·25%) of these cases [2] . Leprosy is mainly prevalent in southwestern provinces of China, including Sichuan, Hunan, Yunnan, and Guizhou [3] . Current evidence suggests that the leprosy household contacts (HHCs) have a higher-risk of developing the disease than the general population [4] .…”

Single-Nucleotide Polymorphisms Related to Leprosy Risk and Clinical Phenotypes Among Chinese Population

“…In China, the overall leprosy incidence is still at a relatively low endemic level, mainly in southwestern provinces, including Sichuan, Hunan, Yunnan and Guizhou. 1 It is estimated that only a small fraction of individuals exposed to M. leprae are successfully infected. 2 The complex interplay between host and pathogens may be one of the explanations for such variability, which is largely influenced by the genetic make-up of the host.…”

“…In China, the overall leprosy incidence is still at a relatively low endemic level, mainly in southwestern provinces, including Sichuan, Hunan, Yunnan and Guizhou. 1 …”