An evidence and reasoning based differential diagnosis of a case of leprosy reinfection from reaction and relapse.

Leprosy is caused by Mycobacterium leprae (M. leprae) and is unique in terms of the chronicity of the disease and its prolonged treatment protocol. Even after the introduction of multidrug therapy (MDT) by World health organization (WHO), large numbers of new cases (nearly 200,000) of leprosy are reported yearly, indicating active transmission, especially in developing countries. Recurrent clinical manifestations after MDT can occur due to leprosy reactions, relapse or reinfection. It is very difficult to differentiate reaction, relapse and reinfection. Here we categorized a recent case of reoccurrence of leprosy as reinfection by differentiating it from reaction and relapse based on evidence and by analysing the clinical data of the patient.

Insights into Mycobacterium leprae Proteomics and Biomarkers-An Overview.

Although leprosy is curable, the identification of biomarkers for the early diagnosis of leprosy would play a pivotal role in reducing transmission and the overall prevalence of the disease. Leprosy-specific biomarkers for diagnosis, particularly for the paucibacillary disease, are not well defined. Therefore, the identification of new biomarkers for leprosy is one of the prime themes of leprosy research. Studying Mycobacterium leprae, the causative agent of leprosy, at the proteomic level may facilitate the identification, quantification, and characterization of proteins that could be potential diagnostics or targets for drugs and can help in better understanding the pathogenesis. This review aims to shed light on the knowledge gained to understand leprosy or its pathogen employing proteomics and its role in diagnosis.

Molecular detection of Mycobacterium leprae using RLEP-PCR in post elimination era of leprosy.

Leprosy is considered as a contagious disease and is still a health problem in several countries including India. Diagnosis of leprosy is based either on clinical findings or on acid fast bacilli staining. Due to low sensitivity of acid fast bacilli staining most of the leprosy cases were remained undetected. The present study aims to assess the efficacy of RLEP-PCR in the field condition where majority of the patients are acid fast bacilli negative and have early disease. A total of 80 suspected leprosy cases were recruited. Slit skin smear samples were taken for microscopy and molecular experimentation. DNA was extracted and RLEP-PCR was executed for all the 80 samples. To establish the statistical correlation χ2 test and Fisher's exact test were made. To elucidate the sensitivity of the test Receiver Operating Characteristic (ROC) was drawn. These 80 leprosy patients comprised of 38 paucibacillary and 42 multibacillary leprosy cases. Of 80 leprosy patients 18 (22.5%) were AFB positive while 53 (66.25%) leprosy cases were RLEP-PCR positive. The results of test of significance (P=0.0001) and Cohen's kappa coefficient (κ) (0.614) indicated that the RLEP-PCR is a better diagnostic tool over AFB microscopy in case detection of leprosy. From the findings we concluded that RLEP-PCR could be used for the definitive detection of leprosy cases in accordance with the clinical findings in the field condition in the post elimination era of leprosy.

Dominant marker (inter-simple sequence repeat-polymerase chain reaction) versus codominant marker (RLEP-polymerase chain reaction) for laboratory diagnosis of leprosy: A comparative evaluation.

Background: Leprosy is a contagious disease and was eliminated globally in 2002. Since then, new cases were continuously detected from different parts of the world. Untreated leprosy cases shed millions of bacteria and are the main cause of dissemination of the disease. Currently, leprosy is detected by acid-fast bacilli (AFB) microscopy and has a low sensitivity ranging from 10% to 50%. The correlation between clinical findings and microscopy is unable to provide a conclusive case detection. Thus, in the present study, we compared to molecular methods, namely RLEP-polymerase chain reaction (RLEP-PCR) and inter-simple sequence repeat-PCR (ISSR-PCR) taking AFB microscopy as a gold standard for the detection of leprosy. Methods: A total of 168 clinically diagnosed leprosy patients were recruited in this study including 58 multibacillary and 110 paucibacillary patients. Slit-skin smear samples were taken for both microscopy and molecular study. Primers for RLEP-PCR were taken from the previous reports. The primers for ISSR-PCR were designed by screening the whole genome of Mycobacterium leprae TN strain (GenBank accession AL450380) for the presence of simple sequence repeats. One primer (TA)8CA3was synthesized and used for molecular amplification of ISSR-PCR. Results: We found that the efficacy of the AFB microscopy was 24.40%, whereas the efficacy of RLEP-PCR and ISSR-PCR was 63.09% and 73.21% (P = 0.000, 0.000, and 0.469), respectively. The area under the curve of receiver operating characteristic curve for the comparison of three diagnostic methods was 0.845. An enhancement of 48.81% in the case detection rate by ISSR-PCR over AFB microscopy and 10.12% over RLEP-PCR was also found. Our study clearly reveals that ISSR-PCR is a better tool for diagnosis of leprosy than AFB microscopy and RLEP-PCR. Interestingly, both the PCR techniques RLEP-PCR and ISSR-PCR are able to detect samples which were negative for AFB microscopy. Conclusion: Thus, the demonstration of ISSR-PCR in SSS samples can provide a better sensitive and confirmative tool for early diagnosis of leprosy.