BackgroundPentavalent antimonials have been the first line treatment for dermal leishmaniasis in Colombia for over 30 years. Miltefosine is administered as second line treatment since 2005. The susceptibility of circulating populations of Leishmania to these drugs is unknown despite clinical evidence supporting the emergence of resistance.Methodology/Principal Findings In vitro susceptibility was determined for intracellular amastigotes of 245 clinical strains of the most prevalent Leishmania Viannia species in Colombia to miltefosine (HePC) and/or meglumine antimoniate (SbV); 163, (80%) were evaluated for both drugs. Additionally, susceptibility to SbV was examined in two cohorts of 85 L. V. panamensis strains isolated between 1980–1989 and 2000–2009 in the municipality of Tumaco. Susceptibility to each drug differed among strains of the same species and between species. Whereas 68% of L. V. braziliensis strains presented in vitro resistance to HePC, 69% were sensitive to SbV. Resistance to HePC and SbV occurred respectively, in 20% y 21% of L. panamensis strains. Only 3% of L. V. guyanensis were resistant to HePC, and none to SbV. Drug susceptibility differed between geographic regions and time periods. Subpopulations having disparate susceptibility to SbV were discerned among L. V. panamensis strains isolated during 1980–1990 in Tumaco where resistant strains belonged to zymodeme 2.3, and sensitive strains to zymodeme 2.2.Conclusions/SignificanceLarge scale evaluation of clinical strains of Leishmania Viannia species demonstrated species, population, geographic, and epidemiologic differences in susceptibility to meglumine antimoniate and miltefosine, and provided baseline information for monitoring susceptibility to these drugs. Sensitive and resistant clinical strains within each species, and zymodeme as a proxy marker of antimony susceptibility for L. V. panamensis, will be useful in deciphering factors involved in susceptibility and the distribution of sensitive and resistant populations.

Resistance to antimonial drugs has been documented inL ong-term use of antimonial drugs as monotherapy for leishmaniasis and nonadherence to treatment have contributed to the increase in treatment failures (3,5). In addition to intrinsic differences in the susceptibility of different Leishmania populations (18, 23), acquired resistance has also been reported (12,15). Consequent variations in drug efficacy impact clinical management and leishmaniasis control programs, yet little is known about the prevalence of tolerant and/or resistant populations (11) and the impact of treatment policies on drug susceptibility.Evaluation of drug susceptibility of clinical strains of Leishmania has been constrained by the unavailability of an efficient method that yields consistent results. Intracellular amastigotes are the target of treatment, are strikingly more susceptible to antimony than promastigotes (2, 11, 21), and importantly, are killed in vitro at clinically achievable drug concentrations. However, drug susceptibility evaluation of clinical strains using intracellular amastigotes is a slow, low-throughput biological assay that is influenced by numerous poorly understood variables. Individual clinical strains are heterogeneous; even strains having a low 50% effective dose (ED 50 ) often contain subpopulations that are effectively resistant (15). Hence, although cloned parasites transfected with reporter genes have proven useful for drug screening (17), the protracted, intensive in vitro antibiotic selection required to recover and maintain the transfected population may alter the original composition of clinical strains and, consequently, the susceptibility phenotype.Conventional susceptibility assays are based on the determination of the ED 50 using murine peritoneal macrophages or macrophage cell lines under diverse conditions of infection with different numbers and intervals of drug concentrations, periods of drug exposure, and readout parameters. Since these factors influence the outcome of the evaluation (20), results of drug susceptibility testing have been neither consistent nor generalizable.We report a novel approach to drug susceptibility assessment of clinical strains of Leishmania based on quantification of parasite burden after exposure to single discriminatory concentrations of two representative antileishmanial drugs, meglumine antimoniate (Sb V ) and miltefosine (HePC). MATERIALS AND METHODSExperimental strategy. Susceptibility of clinical strains of Leishmania (Viannia) species to Sb V and HePC was determined in parallel by conventional dose-response assay and reduction of intracellular parasite burden at a single drug concentration. Discriminatory drug concentrations for susceptibility were defined as follows: the antimony concentration of 32 g Sb V /ml was based on the estimated maximum concentration (C max ) in plasma (6), and the miltefosine concentration of 16 M was chosen because it clearly and consistently distinguished the susceptible wild-type (WT) control strain and an experimentally selected...

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Introduction: Knowledge of the geographical distribution of Leishmania species allows guiding the sampling to little-studied areas and implementing strategies to define risk zones and priority areas for control.Objective: Given that there is no publication that collects this information, the search, review, and compilation of the available scientific literature that has identified species in Colombia is presented in this paper.Materials and methods: A bibliographic search was performed in PubMed, Web of Knowledge, Google Scholar, SciELO and LILACS with the terms “(Leishmania OR Leishmaniasis) AND species AND Colombia”, without restrictions on publication year, language or infected organism; records of national scientific events and repositories of theses from Colombian universities were also included.Results: Eighty-six scientific documents published between 1985 and 2017 were found in which the species of Leishmania and their geographical origin were indicated. The species reported, in descending order of frequency, were: Leishmania (Viannia) panamensis, L. (V.) braziliensis, L. (V.) guyanensis, L. (Leishmania) infantum, L. (L.) amazonensis, L. (L.) mexicana, L. (V.) colombiensis, L. (V.) lainsoni and L. (V.) equatorensis; the last three were found with the same frequency. Leishmania species were reported from 29 departments. Conclusion: Information on the distribution of Leishmania species in Colombia is limited; therefore, it is necessary to gather existing data and propose studies that consolidate the distribution maps of Leishmania species in Colombia. This would allow the detection of areas where species have not been identified as well as the comparison of existing parasite and vector distributions.

ResumenSe estandarizó y evaluó la prueba de ELlSA para el serodiagnóstico de la fascioliasis bovina empleando tres antígenos diferentes de Fasciola hepatica: somático crudo (AgS) y metabólicos, excretor-secretor total (AgE/S-T) y excretor-secretor parcialmente purificado (AgEIS-PP).Se recolectaron treinta muestras de suero de bovinos infectados naturalmente con F: hepatica y parasitológicamente comprobados, sacrificados en mataderos. Estos provenían de regiones de Colombia consideradas zonas endémicas, que se encuentran por encima de los 1.800 metros msnm, y 45 sueros de bovinos de edad y manutención conocida desde el nacimiento hasta su sangría, los cuales vivían en zona no endémica de F: hepatjca y que fueron consideradas como muestras negativas.Se utilizó el análisis del área bajo la curva del receptor operador (ROC) siguiendo el método de integración trapezoidal para establecer la exacitud del ELlSA y discriminar ejemplares parasitados de los sanos. Los tres antígenos de E hepatjca, (AgS) , (AgEI S-T) y (AgE/S PP), debido a su gran capacidad discriminatoria entre bovinos sanos de los infectados, pueden utilizarse en el serodiagnóstico de fascioliasis bovina. SummaryThe enzyme-linked immuno-sorbent assay (ELISA) test for the serodiagnosis of bovine fascioliasis was standardized and evaluated.Three kinds of antigen were employed: crude somatic (SAg), total excretorykecretory (T-EISAg) and partially purified excretoty/secretory (PP-EISAg).Thirty positive samples were obtained from naturally infected canle, parasitological confirmation being positive due to the finding of adult flukes in bile ducts during post-mottem examination. The infected cattle came from regions lying between 1,800 and 2,400 meters above sea level, which are considered to be endemic for this disease.Forty-five negative samples were obtained from cattle living in non-endemic areas, whose age, breeding and growth conditions had been recorded since bitth to the actual moment at which the blood samples were taken.The receiver operator curve (ROC) was used for the evaluation of the ELlSA test, following trapezoidal integration methodology, in order to identify parasitized bovines from