| Abstract: | The FTA card (Whatman) was assessed for its utility as a molecular epidemiological tool in collecting samples from patients with leishmaniasis in Peru because the card has a variety of merits; it is less invasive for patients and easy to handle for both physicians and other medical personnel for sample collection or diagnosis, in addition to its simplicity and easy countrywide and/or intercountry transportation for analysis. Samples were collected from 132 patients suspected of having leishmaniasis, and Leishmania species were successfully identified in samples from 81 patients in 15 departments of Peru by cytochrome b and mannose phosphate isomerase gene analyses. Of these, 61.7% were identified as Leishmania (Viannia) peruviana, 22.2% as L. (V.) braziliensis, 12.3% as L. (V.) guyanensis, 2.5% as L. (V.) shawi, and 1.2% as L. (V.) lainsoni. The three predominant species, L. (V.) peruviana, L. (V.) braziliensis, and L. (V.) guyanensis, were mainly found in the Andean highlands, in the tropical rainforest, and in northern and central rainforest regions, respectively. This is the first time L. (V.) shawi has been identified outside Brazil. The present study showed that the FTA card will be a useful tool for the ecological study of different forms of leishmaniasis. Furthermore, collecting samples directly from patients'' lesions by using the FTA card eliminates (i) the possibility of contamination of Leishmania isolates during short- and/or long-term passages of culture in vitro in each laboratory and (ii) pain and suffering of patients from taking samples by skin biopsy.Leishmaniasis is caused by protozoan parasites of the genus Leishmania, which is further divided into two subgenera, Leishmania (Leishmania) and Leishmania (Viannia) (10). The disease is widely distributed around the world, especially in tropical and subtropical areas, affecting at least 12 million people in 88 countries (6). Approximately 20 Leishmania species are known to be pathogenic to humans, and the species is the major determinant of clinical outcome (cutaneous, mucocutaneous, and visceral forms) (6). Therefore, identification of the parasite species in areas of endemicity is important for both appropriate treatment and prognosis.The standard method for the classification of Leishmania species is multilocus enzyme electrophoresis (MLEE), which requires the isolation and mass culture of the parasites (4, 17). This process has several disadvantages: (i) risk of contamination with bacteria and/or fungus and even other Leishmania isolates in the laboratory; (ii) maladaptation of the parasites to the artificial medium; (iii) difficulty in cultivation due to low numbers of parasites in cutaneous lesions, especially for the subgenus Leishmania (Viannia); and (iv) the time, several weeks or months, required to obtain a result after sample collection. All of these factors affect epidemiological studies in spite of considerable efforts to collect patient specimens from different areas of endemicity, especially for specimens from remote locations. To overcome these problems, molecular biological methods have been developed for the detection and identification of Leishmania species using DNA extracted from clinical samples (7, 16, 21). However, sampling procedures, such as skin biopsy, are sometimes painful for patients and become a burden to both patients and physicians. Therefore, alternative sampling procedures with less invasiveness, simple and easy handling, and greater convenience are required for the detection and identification of Leishmania species and continuous monitoring of endemic species of causative organisms.FTA technology (Whatman) is a rapid and safe method for extracting nucleic acids from blood, cell, and pathogen samples without using any organic solvent or specialized equipment. When the samples are spotted onto an FTA card, the cells are readily lysed and the nucleic acids are fixed on the card, resulting in protection from nuclease, oxidative, and UV damage and prevention of the growth of bacteria and other microorganisms. The card is also suitable for long-term storage and the transportation of materials at room temperature, eliminating the possibility of contamination from isolates in vitro during the laboratory phase. In the present study, the utility of FTA cards was assessed for sample collection for the countrywide molecular epidemiological study of leishmaniasis in Peru. |
