In South America, various species of Leishmania are endemic and cause New World tegumentary leishmaniasis (NWTL). The correct identification of these species is critical for adequate clinical management and surveillance activities. We developed a real-time polymerase chain reaction (PCR) assay and evaluated its diagnostic performance using 64 archived parasite isolates and 192 prospectively identified samples collected from individuals with suspected leishmaniasis enrolled at two reference clinics in Lima, Peru. The real-time PCR assay was able to detect a single parasite and provided unambiguous melting peaks for five Leishmania species of the Viannia subgenus that are highly prevalent in South America: L. (V.) braziliensis, L. (V.) panamensis, L. (V.) guyanensis, L. (V.) peruviana and L. (V.) lainsoni. Using kinetoplastid DNA-based PCR as a gold standard, the real-time PCR had sensitivity and specificity values of 92% and 77%, respectively, which were significantly higher than those of conventional tests such as microscopy, culture and the leishmanin skin test (LST). In addition, the real-time PCR identified 147 different clinical samples at the species level, providing an overall agreement of 100% when compared to multilocus sequence typing (MLST) data performed on a subset of these samples. Furthermore, the real-time PCR was three times faster and five times less expensive when compared to PCR - MLST for species identification from clinical specimens. In summary, this new assay represents a cost-effective and reliable alternative for the identification of the main species causing NWTL in South America.

Military personnel deployed to the Amazon Basin are at high risk for cutaneous leishmaniasis (CL). We responded to an outbreak among Peruvian Army personnel returning from short-term training in the Amazon, conducting active case detection, lesion sample collection, and risk factor assessment. The attack rate was 25% (76/303); the incubation period was 2–36 weeks (median = 8). Most cases had one lesion (66%), primarily ulcerative (49%), and in the legs (57%). Real-time polymerase chain reaction (PCR) identified Leishmania (Viannia) braziliensis (59/61 = 97%) and L. (V.) guyanensis (2/61 = 3%). Being male (risk ratio [RR] = 4.01; P = 0.034), not wearing long-sleeve clothes (RR = 1.71; P = 0.005), and sleeping in open rooms (RR = 1.80; P = 0.009) were associated with CL. Sodium stibogluconate therapy had a 41% cure rate, less than previously reported in Peru (∼ 70%; P < 0.001). After emphasizing pre-deployment education and other basic prevention measures, trainees in the following year had lower incidence (1/278 = 0.4%; P < 0.001). Basic prevention can reduce CL risk in deployed militaries.

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In previous works we reported the finding of neurotrophic activity in a serum-free Dulbecco's modified Eagle's medium conditioned by rat sciatic nerves, previously maintained in culture for 11 days. This medium produces rapid neuron-like differentiation of cultured PC12 cells, as revealed by an increase in the size of the cell body and by the extension of short and/or long neurites by most of the cells. Neuregulin present in the conditioned medium was demonstrated to play a key role in the observed differentiation. In the present work, taking into consideration those latter results, the neurotrophic activity of conditioned media prepared with sciatic and optic nerves cultured during days 1-4 and 9-12 were studied. Evaluation of the trophic activities of those media revealed an opposite timing in the activities of sciatic and optic nerves conditioned media. The activity of the sciatic nerve was not observed in the 1-4-day period, increasing then up to the 9-12-day period. On the contrary, the optic nerve conditioned medium was active in the 1-4-day period, decreasing down to the 9-12-day period. These results led us to explore the contribution of the different cellular constituents of those nerves to their neurotrophic properties. As a first step in that direction we also investigated the neurotrophic activity of media conditioned during 12 days by cultured Schwann cells isolated from rat sciatic nerves. The Schwann cell conditioned media did produce a rapid differentiation of the PC12 cells similar to that caused by the sciatic nerve conditioned medium, though of a lower magnitude. Variations in the trophic activities of the conditioned media used in the present work is discussed taking into consideration the production of trophic and inhibitory factors by the peripheral and central glial cells. The role played by the optic nerve glia and myelin is being investigated at present.

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