ABSTRACT A retrospective analytical method is presented, based on theoretical eco-epidemiology, applied on a subnational spatial scale. This method was used here to describe scenarios for the transmission of leishmaniasis in the Argentine province of Misiones— bordering Brazil and Paraguay—and formed the basis for recommendations for surveillance and control appropriate to the subnational scale. An exhaustive search of the literature on leishmaniasis in the province was carried out. Three scenarios for the transmission of cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) were found, corresponding to three periods: from 1920 to 1997, during which the transmission of CL distributed over time and space was confirmed; 1998 to 2005, during which there were focal outbreaks of CL; and 2006 to 2014, during which outbreaks were also reported and the geographical dispersion of VL was documented. To describe the risk scenarios and the anthropic processes that produce them, the results were summarized and integrated into the social, historical, and bio-ecological context of each period. Surveillance and control recommendations are based on the territory studied. They include establishing active surveillance to monitor possible rising trends in parasitic and vector circulation, conducting studies of any focal outbreak in order to confirm indigenous transmission and severity. Also, it should be a legal requirement for persons responsible for projects that alter the environment to adopt additional control measures, such as studies assessing transmission risk, risk mitigation, early detection, and timely case management.

RESUMEN Se presenta una metodología analítica retrospectiva, basada en el marco teórico de la eco-epidemiología, anclada en una escala espacial subnacional. Esta metodología, aplicada aquí a la caracterización de escenarios de transmisión de la leishmaniasis en la provincia argentina de Misiones —fronteriza con Brasil y Paraguay— permitió fundamentar recomendaciones de vigilancia y control apropiadas a dicha escala. Se realizó una búsqueda exhaustiva de la literatura sobre leishmaniasis en esa provincia y se determinaron tres escenarios de transmisión de leishmaniasis cutánea (LC) y visceral (LV), correspondientes a tres períodos: 1920-1997, en el que se constató la transmisión de LC, dispersa en el tiempo y el espacio; 1998-2005, en el que hubo brotes focales de LC; y 2006-2014 en el que, además, se registraron brotes y se documentó la dispersión geográfica de la LV. Para caracterizar los escenarios de riesgo y los procesos antrópicos que los producen, los resultados se sintetizaron e integraron en el contexto socio-histórico y bio-ecológico de cada período analizado. Se fundamentan recomendaciones de vigilancia y control en el territorio estudiado, entre ellas, establecer una vigilancia activa para monitorear posibles tendencias al incremento de la circulación parasitaria y vectorial y, ante la aparición de un foco, realizar estudios para verificar la transmisión autóctona y la intensidad del evento. Además, se debe establecer la obligación legal de tomar medidas adicionales de control por los responsables de los proyectos que impliquen modificación ambiental, como la realización de estudios de evaluación del riesgo de transmisión, y acciones de mitigación del riesgo, detección temprana y tratamiento oportuno de los casos.

In this study, a genotypification of Leishmaniawas performed using polimerase chain reaction-restriction fragment length polymorfism (PCR-RFLP) and sequencing techniques to identify species of Leishmaniaparasites in phlebotomine sand flies and dogs naturally infected. Between January-February of 2009, CDC light traps were used to collect insect samples from 13 capture sites in the municipality of Posadas, which is located in the province of Misiones of Argentina. Sand flies identified as Lutzomyia longipalpiswere grouped into 28 separate pools for molecular biological analysis. Canine samples were taken from lymph node aspirates of two symptomatic stray animals that had been positively diagnosed with canine visceral leishmaniasis. One vector pool of 10 sand flies (1 out of the 28 pools tested) and both of the canine samples tested positively for Leishmania infantumby PCR and RFLP analysis. PCR products were confirmed by sequencing and showed a maximum identity with L. infantum. Given that infection was detected in one out of the 28 pools and that at least one infected insect was infected, it was possible to infer an infection rate at least of 0.47% for Lu. longipalpisamong the analyzed samples. These results contribute to incriminate Lu. longipalpis as the vector of L. infantumin the municipality of Posadas, where cases of the disease in humans and dogs have been reported since 2005.