Department of Epidemiology, National JALMA Institute for Leprosy and Other Mycobacterial Diseases, M. Miyazaki Marg, Tajganj, Agra, India.
Clinical Division, National JALMA Institute for Leprosy and Other Mycobacterial Diseases, M. Miyazaki Marg, Tajganj, Agra, India.
PLoS One. 2019 Apr 4;14(4):e0214051. doi: 10.1371/journal.pone.0214051. eCollection 2019.
Leprosy is a slow, chronic disorder caused by Mycobacterium leprae. India has achieved elimination of leprosy in December 2005 but new cases are being detected and continue to occur in some endemic pockets. The possible ways of transmission of leprosy is not fully understood and is believed that leprosy is transmitted from person to person in long term contact. Studying the transmission dynamics is further complicated by inability to grow M. leprae in culture medium and lack of animal models. More than one family members were found to be affected by leprosy in some highly endemic pockets. This study reported the transmission pattern of leprosy in a family having 4 patients.
METHODOLOGY/PRINCIPAL FINDINGS: We investigated the transmission of leprosy in a single family having 4 patients using microsatellite typing. DNA was isolated from slit skin smear samples taken from the patients and the isolated DNA were amplified using microsatellite loci TA11CA3. The amplified products were sequenced using Sanger's sequencing methods and the copy number variation in the microsatellite loci between strains were elucidated by multiple sequence alignment. The result showed that all the 4 members of the family acquired infection from 3 different strains of M. leprae from 3 different sources. The elder and middle daughters were infected by same types of strains having the repeat unit TA13CA3 and could have acquired the infection from social contacts of leprosy cases while the father and younger daughter were infected by strains with the repeat unit TA12CA3 and TA11CA3 and could have acquired infection from social contacts.
CONCLUSIONS/SIGNIFICANCE: The study suggested that three family members viz, elder daughter, father and younger daughter could be infected by M. leprae from 3 different sources and the history of the disease and genetic analysis showed that the middle daughter acquired infection from her elder sister in due course of contact. This study implies that the transmission of leprosy not only occurred amongst the house hold members but also has been transmitted from social and neighborhood contacts in long term association with the them.
麻风病是一种由麻风分枝杆菌引起的慢性、进行性疾病。印度已于 2005 年 12 月实现了麻风病消除目标，但仍有新病例被发现，并在一些流行地区继续发生。麻风病的传播途径尚未完全了解，据信麻风病是通过长期接触人与人之间传播的。由于无法在培养基中培养麻风分枝杆菌，也缺乏动物模型，因此研究其传播动力学变得更加复杂。在一些高度流行地区，发现不止一个家庭成员受到麻风病的影响。本研究报告了一个家庭中有 4 名患者的麻风病传播模式。
方法/主要发现：我们使用微卫星分型研究了一个家庭中 4 名患者的麻风病传播情况。从患者的皮肤划痕样本中提取 DNA，使用微卫星位点 TA11CA3 扩增分离的 DNA。使用 Sanger 测序方法对扩增产物进行测序，并通过多序列比对阐明了菌株之间微卫星位点的拷贝数变异。结果表明，该家庭的 4 名成员均从 3 个不同来源的 3 种不同麻风分枝杆菌菌株感染。长女和次女感染了具有 TA13CA3 重复单元的相同类型菌株，可能是通过与麻风病例的社会接触而感染的，而父亲和小女儿感染了具有 TA12CA3 和 TA11CA3 重复单元的菌株，可能是通过与社会接触而感染的。
结论/意义：研究表明，3 名家庭成员，即长女、父亲和小女儿，可能是从 3 个不同来源感染了麻风分枝杆菌，病史和遗传分析表明，次女是在与姐姐的接触过程中感染的。本研究表明，麻风病的传播不仅发生在家庭内部，也发生在与他们长期接触的社会和邻里关系中。
