Abstract Haemagogus leucocelaenus (Diptera: Culicidae) is considered the primary vector of yellow fever virus (Flaviviridae) in wild environments in South America. Previous research has defined Hg. leucocelaenus as a wild species with phytotelmata-type breeding sites. The objective of this study was to report the temporal and space occurrence of Hg. leucocelaenus at the microscale in the wild-periurban fringe through a systematic and spatially stratified sampling using 81 ovitraps between April 2019 and February 2020 in the locality of Puerto Iguazú, Argentina. Of the total ovitraps, eight were positive for Hg. leucocelaenus, six in the wild environment and two in the periurban environment. Regarding the time distribution, 98.5% of the occurrence was concentrated in November and December 2019 towards the beginning of the rainy season. The results confirm the habitat plasticity of Hg. leucocelaenus and establish the aptitude of artificial containers as a methodology in monitoring studies, since they illustrate the potential of wild populations to deposit fertile eggs in them at least up to 300 m from the wild-periurban fringe. This work is a contribution to determine the temporal and space risk of yellow fever virus transmission in the region, based on the distribution patterns of this species as a function to the ecotone associated with forest borders and climatic variables.

Resumen Haemagogus leucocelaenus (Diptera: Culicidae) se considera el principal vector del virus de la fiebre amarilla (Flaviviridae) en entornos silvestres de Sudamérica. Investigaciones anteriores han definido a Hg. leucocelaenus como una especie silvestre con sitios de reproducción natural en fitotelmata. El objetivo de este estudio fue reportar la ocurrencia espacio-temporal de Hg. leucocelaenus a microescala en la franja silvestre-periurbana a través de un muestreo sistemático y espacialmente estratificado utilizando 81 ovitrampas realizado entre abril del 2019 y febrero del 2020 en la localidad de Puerto Iguazú, Argentina. Del total de las ovitrampas colocadas, ocho fueron positivas para Hg. leucocelaenus, seis en el ambiente selvático y dos en el periurbano. En cuanto a la distribución temporal, el 98,5% de las apariciones se concentraron en noviembre y diciembre de 2019, hacia el inicio de la temporada lluviosa. Estos resultados confirman la plasticidad del hábitat de Hg. leucocelaenus y establecen la aptitud de los contenedores artificiales como metodología en los estudios de seguimiento, ya que ilustran el potencial de las poblaciones silvestres para depositar huevos fértiles en ellos, al menos hasta 300 m de la franja silvestre-periurbana. Este trabajo es una contribución al riesgo espacio-temporal de transmisión del virus de la fiebre amarilla en la región, a partir de los patrones de distribución de esta especie en función del ecotono asociado a los bordes silvestres y variables climáticas.

BACKGROUND Visceral leishmaniasis (VL) is an endemic disease in northeastern Argentina including the Corrientes province, where the presence of the vector and canine cases of VL were recently confirmed in December 2008. OBJECTIVES The objective of this study was to assess the modelling of micro- and macro-habitat variables to evaluate the urban environmental suitability for the spatial distribution of Lutzomyia longipalpis presence and abundance in an urban scenario. METHODS Sampling of 45 sites distributed throughout Corrientes city (Argentina) was carried out using REDILA-BL minilight traps in December 2013. The sampled specimens were identified according to methods described by Galati (2003). The analysis of variables derived from the processing of satellite images (macro-habitat variables) and from the entomological sampling and surveys (micro-habitat variables) was performed using the statistical software R. Three generalised linear models were constructed composed of micro- and macro-habitat variables to explain the spatial distribution of the abundance of Lu. longipalpis and one composed of micro-habitat variables to explain the occurrence of the vector. FINDINGS A total of 609 phlebotominae belonging to five species were collected, of which 56% were Lu. longipalpis. In addition, the presence of Nyssomyia neivai and Migonemya migonei, which are vectors of tegumentary leishmaniasis, were also documented and represented 34.81% and 6.74% of the collections, respectively. The explanatory variable normalised difference vegetation index (NDVI) described the abundance distribution, whereas the presence of farmyard animals was important for explaining both the abundance and the occurrence of the vector. MAIN CONCLUSIONS The results contribute to the identification of variables that can be used to establish priority areas for entomological surveillance and provide an efficient transfer tool for the control and prevention of vector-borne diseases.

RESUMO O primeiro caso humano autóctone de leishmaniose visceral (LV) na Argentina ocorreu na cidade de Posadas (Misiones) em 2006, desde então, tem ocorrido um aumento na incidência e distribuição geográfica da doença. No período entre 2006 e 2012 foram detectados 107 casos humanos com 11 mortes. Em 2010 se constatou a presença de Lutzomyia longipalpis no município de Puerto Iguazú, localizado na fronteira entre Argentina-Brasil-Paraguai. O presente estudo teve como objetivo investigar a abundância e distribuição de Lu. longipalpis no município de Puerto Iguazú. Lu. longipalpis foi encontrada exclusivamente na área urbana, em 31% das amostras coletadas dos domicílios de referência (n = 53), 67% das quais pertenciam às áreas de baixa abundância, 20% às de moderada e 13% às de alta abundância da espécie. Nyssomyia whitmani foi coletado em ambientes urbanos e periurbanos e Migonemyia migonei, somente nas periferias da cidade. Na atualidade, a cidade de Puerto Iguazú é considerada como de risco moderado; por isso, é necessário intensificar o controle tanto de casos humanos como de caninos e levar em conta as medidas de prevenção e controle do ambiente, dos vetores e dos reservatórios na zona de fronteira Argentina-Brasil-Paraguai.

SUMMARY The first Argentinian autochthonous human case of visceral leishmaniasis (VL) was confirmed in Posadas (Misiones) in 2006. Since then, the disease has increased its incidence and geographical distribution. In the 2006-2012 period, 107 human cases were detected (11 deaths). The presence of Lutzomyia longipalpis was detected in peridomiciles in Puerto Iguazú urban area in 2010; some of these findings were associated with households where cases of canine VL had already been reported. The objective of this study was to ascertain the abundance and spatial distribution of Lu. longipalpis in Puerto Iguazú City, on the Argentina-Brazil-Paraguay border. Lu. longipalpis proved to be exclusively urban and was found in 31% of the households sampled (n = 53), 67% of which belonged to areas of low abundance, 20% to areas of moderate abundance and 13% to areas of high abundance. Nyssomyia whitmani was the only species found both in urban and peri-urban environments, and Migonemyia migonei was registered only on the outskirts of the city. Due to the fact that Puerto Iguazú is considered to be at moderate risk at the moment, it is necessary to intensify human and canine case controls, as well as take integrated prevention and control measures regarding the environment, vectors and reservoirs on the Argentina-Brazil-Paraguay border area.