Fluconazole effectiveness against Leishmania (Viannia) braziliensis: is the evidence enough?

To the Editor—We appreciate Drs Torres and Suárez's interest in our article, “High-Dose Oral Fluconazole Therapy Effective for Cutaneous Leishmaniasis Due to Leishmania (Vianna) braziliensis” [1]. They refer to evidence of Leishmania amazonensis isolated from human as well as domestic and wild reservoir hosts from the state of Ceará and suggest it is an important etiologic agent of cutaneous leishmaniasis in the region. Concerning human hosts, their statement is based on 2 publications [2, 3] that showed a single isolate of L. amazonensis from only 1 human case of cutaneous leishmaniasis. Both articles deal with the same parasite grown from a human skin biopsy sample in 1984. Because that event was so rare, the question as to whether it was an imported case remains. In respect to domestic and wild reservoirs of L. amazonensis in the state of Ceará, there is no proof of isolates of L. amazonensis from any reservoir or from sandflies. The data available for isolates from humans [4-7], from domestic and wild reservoir hosts [4, 6], and from sandflies [4, 6, 8, 9] support our statement: Leishmania (Viannia) braziliensisis is the only known agent of cutaneous leishmaniasis in the state of Ceará. In a large study of 272 human isolates from 39 different municipalities, all were characterized as L. braziliensis [5]. In another report [6], the author studied 354 isolates from humans, rodents, dogs, and sandflies; all were characterized as L. braziliensis. Furthermore, because the patients in our study were from several different endemic areas, the hypothesis that the response of our patients was due to aspecific clinical syndrome caused by L. braziliensis from a specific endemic area is not true. The lymphadenopathy described in L. braziliensis infection [5] has been documented in other regions of Brazil, and its detection depends on the moment patients seek medical attention and on a comprehensive physical examination because this lymphadenopathy is an early manifestation of infection and, as a rule, the lymphadenopathy is painless and abates as the ulcer progresses. There is evidence that 1 strain of L. braziliensis from 1 region may be genetically different from another strain from other regions [10], and it is possible that these strains may respond differently to therapy. Hence, it is critically important that fluconazole be tested in other areas where L. braziliensis and other species of Leishmania are endemic, keeping in mind that optimal weight-based dosing is very likely to be an important determinant of therapeutic success [1].