Use of PCR in diagnosis of human American tegumentary leishmaniasis in Riode Janeiro, Brazil

In Brazil, the most common etiological agent of American tegumentary leishm aniasis is Leishmania (Viannia) braziliensis, In general, diagnostic techni ques envisage the visualization of the parasite, but that technique has a l ow sensitivity. The main purpose of the present work was to evaluate the PC R as a routine tool for the diagnosis of leishmaniasis, Biopsy specimens fr om cutaneous or mucosal lesions were taken from 230 individuals from areas where Leishmania is endemic: 216 patients who had a clinical picture sugges tive of leishmaniasis and 14 individuals with cutaneous lesions due to othe r causes. Each specimen was processed for histopathologic examination, cult ure, touch preparation, and DNA isolation. Oligonucleotides that amplify th e conserved region of the minicircle molecules of Leishmania were used in a hot-start PCR, While at least one conventional technique was positive for Leishmania for 62% (134 of 216) of the patients, PCR coupled to hybridizati on was positive for 94% (203 of 216) of the patients. The 14 patients whose clinical picture was not suggestive of leishmaniasis had negative results by all techniques, The impact of the PCR was striking in mucosal disease, W hile the disease in only 17% (4 of 24) of the patients could be diagnosed b y conventional techniques, PCR was positive for 71% (17 of 24) of the patie nts. Hybridization showed that all cases of disease were caused by parasite s belonging to the Viannia subgenus, Altogether, the results indicate that PCR is a valuable tool for the diagnosis of leishmaniasis on a routine basi s and is likely to provide valuable epidemiological information about the d isease in countries where it is endemic.