Comparison of Three Polymerase Chain Reaction Protocols for the Diagnosis of Leprosy in Ecuador

Leprosy or Hansen's disease remains a public health concern in Ecuador, where diagnosis still relies on clinical evaluation and bacilloscopy. This pilot study evaluated the performance of three polymerase chain reaction (PCR) protocols for detection of Mycobacterium leprae in 31 clinical specimens from patients clinically suspected of leprosy. Two real-time PCR assays (quantitative polymerase chain reaction [qPCR]) and one conventional PCR were compared with bacilloscopy. The two qPCR assays showed identical positivity rates of 32.3% (n = 10/31), whereas the conventional PCR detected only 3.2% (n = 1/31) positives. Overall, PCR positivity was 38.7% (n = 12/31) compared with 25.8% (n = 8/31) for bacilloscopy. The combined reference standard (considering a sample true positive when either bacilloscopy or PCR was positive) diagnosed 45.2% (n = 14/31) of samples as positive. A significant lower sensitivity was observed for conventional PCR compared with qPCR. These findings support the use of qPCR together with bacilloscopy to improve leprosy diagnosis in Ecuador.