Multiplex PCR technique could be an alternative approach for early detection of leprosy among close contacts - a pilot study from India

Surajita Banerjee,Kamalesh Sarkar,Chaitry Ghosal,Soma Gupta,Suman Kalyan Paine,Rathindra Nath Dutta,Siddhartha Gupta,Nibir Biswas,Samudra Guha,Prasanta Sinha Mahapatra,Debasis Bandhopadhayay,Basudev Bhattacharya

doi:10.1186/1471-2334-10-252

Abstract

BackgroundImplementation of Multi drug Therapy (MDT) regimen has resulted in the decline of the total number of leprosy cases in the world. Though the prevalence rate has been declining, the incidence rate remains more or less constant and high in South East Asian countries particularly in India, Nepal, Bangladesh, Pakistan and Srilanka. Leprosy, particularly that of multibacillary type spreads silently before it is clinically detected. An early detection and treatment would help to prevent transmission in the community. Multiplex PCR (M-PCR) technique appears to be promising towards early detection among contacts of leprosy cases.MethodsA total of 234 paucibacillary (PB) and 205 multibacillary (MB) leprosy cases were studied in a community of an endemic area of Bankura district of West Bengal (Eastern India). They were assessed by smear examination for acid-fast bacilli (AFB) and M-PCR technique. These patients were treated with Multidrug Therapy (MDT) as prescribed by WHO following detection. A total of 110 MB and 72 PB contacts were studied by performing M-PCR in their nasal swab samples.Results83.4% of MB patients were observed to be positive by smear examination for AFB and 89.2% by M-PCR. While 22.2% of PB patients were found to be positive by smear examination for AFB, 80.3% of these patients were positive by M-PCR. Among leprosy contacts (using M-PCR), 10.9% were found to be positive among MB contacts and 1.3% among PB contacts. Interestingly, two contacts of M-PCR positive MB cases developed leprosy during the period of two years follow up.ConclusionThe M-PCR technique appears to be an efficient tool for early detection of leprosy cases in community based contact tracing amongst close associates of PB and MB cases. Early contact tracing using a molecular biology tool can be of great help in curbing the incidence of leprosy further.

Highlights

Implementation of Multi drug Therapy (MDT) regimen has resulted in the decline of the total number of leprosy cases in the world
Patients were grouped in the following categories: (i) Patients without treatment, (ii) Patients on treatment not more than two months, (iii) Patients complaining of hypoesthesia but showing no clinical symptoms of leprosy - considered as Indeterminate type, and (iv) Patients released from treatment (RFT) and later developed a new active lesion/i.e. relapsed cases
The findings of Multiplex PCR (M-PCR) and Bacterial Index (BI) of Slit skin smear (SSS) are presented in table 1

Summary

Introduction

Implementation of Multi drug Therapy (MDT) regimen has resulted in the decline of the total number of leprosy cases in the world. Though the prevalence rate has been declining, the incidence rate remains more or less constant and high in South East Asian countries in India, Nepal, Bangladesh, Pakistan and Srilanka. The global caseload of leprosy has reduced by almost 90% over the last 20 years and 15 million cases have been detected and cured worldwide. India alone accounted for 60% of the world’s newly detected cases [1,3]. This might be due to lack of consistent information on the core elements of this infectious disease, e.g. source of infection, reservoir and mode of transmission, host factors related to immunity of disease etc [4,5,6]. It has been observed that though prevalence has declined since initiation of MDT, the incidence has not shown a similar decline during the same period i.e. after implementation of MDT [7,8,9,10]

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