Cryptic Diversity in Sympatric Migonemyia migonei (Diptera: Psychodidae), Eventual Meaning for Leishmaniasis Transmission.

Migonemyia migonei (FranÒ«a, 1920) (Diptera: Psychodidae) belongs to the subfamily Phlebotominae, of epidemiological importance due to its role as a vector in leishmaniasis transmission cycles and its broad geographic distribution in South America. Few morphometric and genetic studies have demonstrated the existence of variability among geographically distant populations in Brazil. The aim of the study was to estimate the genetic distance within the morphospecies Mg. migonei through the analysis of cytochrome C oxidase subunit I (COI) sequences of specimens captured in Argentina and those available in online databases. The COI sequences from specimens collected in different localities of Argentina and sequences available in online databases were utilized. Genetic distances were analyzed and a median-joining haplotype network was constructed. Finally, phylogenetic reconstruction was performed according to Bayesian inference. The analyses led to the identification of at least two haplogroups: haplogroup I with sequences of specimens from Colombia, Brazil and Argentina, and haplogroup II with sequences of specimens from Argentina. Interestingly, specimens from Argentina whose haplotypes corresponded to both haplogroups, were collected in sympatry. The results suggest that Mg. migonei could be a species complex with at least two distinct members. This hypothesis could explain the known characteristics of adaptability and vector permissiveness of the species, as the putative cryptic species of the complex could differ in traits of epidemiological importance.

Household ovicidal alternative for complementary control of Aedes aegypti in the Gran San Miguel de Tucuman agglomerate, Tucumán, Argentina.

Aedes aegypti is closely related to human behavior that allows its establishment through the accumulation of urban solid waste where it lays resistant eggs. Generally, adulticides and larvicides are applied in excess, without ovicidal alternatives, and some household products can help reduce the abundance of quiescent eggs in breeding sites by affecting the viability of eggs. A community involved in prevention and control is one of the most effective strategies for adequate vector management. In this investigation, new alternative strategies for the control of Ae. aegypti are assessed, valuing in laboratory the eggs' response to diverse household products. Susceptibility to different doses of bleach, oil, salt, sodium bicarbonate, vinegar, coffee, garlic, peroxide, and alcohol was measured, as well as its duration over time. New home products were found as alternative ovicidal method. Bleach and sunflower oil had an ovicidal effect at their maximum doses and at almost all of the evaluation times. In contrast, vinegar and coffee had no ovicidal effect at any time, turning out to be stimulators of hatching in the laboratory. These alternative and complementary applications could optimize the surveillance and control of Ae. aegypti in the area, allowing new approaches to reduce populations by eliminating eggs on human microhabitats.

Abundance of Lutzomyia longipalpis and Nyssomyia whitmani, the Leishmania spp. vectors in northeastern of Argentina: Are spatial and temporal changing patterns consistence?

Lutzomyia longipalpis and Nyssomyia whitmani were incriminated as vectors of Leishmania sp. Spatial heterogeneity together with seasonal changes in abundance constitute important elements for the understanding of the dynamics of vector populations, and there are fundamental for the development of adequate prevention and control strategies. The aim of this work was to compare the spatial and seasonal abundance of Lu. longipalpis and Ny. whitmani at a city spatial scale between two periods separated by three years. To study the spatial distribution, we compared the abundance distribution of these species at two warm times, 2011 with 2014. Respect to inter-annual seasonal abundance changes, we compared the four seasons of the year between two periods (2011-2012 vs 2014-2016). The spatial distribution for both species were found to be distributed mainly in the same areas of the city in both periods. We change for: Respect to the seasonal pattern of abundance, we observed that seasonal patterns showed changes between periods. Our study defines the 'where' and 'when' implement the actions to mitigate leishmaniasis cases.

Update of the Phlebotominae Fauna with New Records for Argentina and Observations on Leishmaniasis Transmission Scenarios at a Regional Scale.

Phlebotominae are small insects distributed in the Americas from Canada to Argentina and Uruguay, counting with more than 500 neotropical species. Some of them have a vectorial role in the transmission of Leishmania Ross, the causative agent of leishmaniases, a group of worldwide distributed diseases with different clinical manifestations and transmission cycles. Our aim was to update the Phlebotominae fauna of Argentina and to make observations on the American Cutaneous (ACL) and Visceral Leishmaniasis (AVL) transmission scenarios, according to the distribution of proven or suspected Leishmania vector species and recent changes in land use. Primary data (entomological captures) and secondary data (review of 65 scientific publications with Phlebotominae records) were used. With 9 new records, 46 Phlebotominae species are now recorded through the area comprising 14 political jurisdictions and 6 phytogeographic provinces. Distribution maps were constructed for the 5 proven or incriminated Leishmania vector species, and the evidence supporting the vectorial incrimination of these species is discussed. Three main ACL transmission scenarios are described in the phytogeographic provinces of the Yungas, Chaco, and Paranaense, associated with deforestation processes, while the transmission scenarios of AVL are urban outbreaks and scattered cases in rural areas. We update the available knowledge on the Phlebotominae fauna present in Argentina, emphasizing its epidemiological relevance in the current context of the increasing frequency of ACL outbreaks and geographic spread of AVL.

Multiscale environmental determinants of Leishmania vectors in the urban-rural context.

BACKGROUND: In South America, cutaneous leishmaniasis (CL) and visceral leishmaniasis (VL) are emerging diseases, expanding in the border area of Argentina, Brazil and Paraguay. Outbreaks of CL were reported since the 1990s, with Nyssomyia whitmani as the main vector in this region. Regarding VL, urban reports started in 2010 with Lutzomyia longipalpis as the main vector. The aim of this study was to evaluate environmental determinants related to the main vectors of leishmaniasis, to contribute to the prevention and control response to the emergence of VL and CL in the Argentina-Brazil-Paraguay border region. METHODS: The cross-sectional survey includes two cities and two close rural areas in the Argentinean Northeast Region, between November 2014 and January 2015, with a total of 95 sampling sites. REDILA-BL traps were set for three consecutive nights, and a total of 68 meso- and microscale environmental and landscape characteristics were surveyed. The association between vector abundance with different variables was evaluated using a generalized linear model with zero-inflated negative binomial distribution. We analyzed females for detection of Leishmania DNA. RESULTS: The analysis for Lu. longipalpis indicates an excess of absences when the mean NDWI around the sites were higher. The abundance of Lu. longipalpis at mesoscale level was higher when more urban services were present, and when blood sources such as chickens or dogs at the microscale level were present. For Ny. whitmani, no variable was found to be associated with the absences, while its abundance increased in association with the following variables: percentage of tree cover, presence of garbage collection service, hosted people and, at microscale, the presence of poultry. Leshmania infantum DNA was detected in 2/49 (4%) Lu. longipalpis. CONCLUSIONS: The abundance of both species is influenced by variables at different scales, their influence probably has a hierarchy and they are acting on different aspects of the biology of these vectors. The urban spatial segregation of Lu. longipalpis and the peri-urban and rural segregation of N. whitmani increase the risk of VL and CL. The selection of the better variables for each scale will allow the design of appropriate control strategies depending on species.

Phylogenetic relationships of closely-related phlebotomine sand flies (Diptera: Psychodidae) of Nyssomyia genus and Lutzomyia subgenus.

BACKGROUND: The Nyssomyia genus and Lutzomyia subgenus include medical important species that are Latin American leishmaniases vectors. Little is known about the phylogenetic relationships of closely-related species in each of these taxonomic groups that are morphologically indistinguishable or differentiated by very subtle details. OBJECTIVES: We inferred the phylogenetic relationships of closely-related species within both the Nyssomyia genus and the Lutzomyia subgenus using a cytochrome c oxidase subunit I (COI) fragment. METHODS: The sampling was carried out from 11 Argentinean localities. For genetic analyses, we used GenBank sequences in addition to our sequences from Argentina. Kimura 2-parameter (K2P) genetic distance and nucleotide divergence (Da) was calculated between closely-related species of Nyssomyia genus, Lutzomyia subgenus and between clades of Lutzomyia longipalpis complex. FINDINGS: The K2P and Da values within species of Nyssomyia genus and Lutzomyia subgenus were lower than the divergence detected between clades of Lu. longipalpis complex. The haplotype network analyses within Lutzomyia subgenus showed shared haplotypes between species, contrary to Nyssomyia genus with none haplotype shared. Bayesian inference within Nyssomyia genus presented structuring by species. MAIN CONCLUSIONS: This study evidences the phylogenetic proximity among closely-related species within Nyssomyia genus and Lutzomyia subgenus. The COI sequences of Nyssomyia neivai derived from the present study are the first available in GenBank.

Lutzomyia longipalpis (Diptera: Psychodidae) Argentina-Bolivia border: new report and genetic diversity.

American visceral leishmaniasis (AVL) has two main scenarios of transmission as follows: scattered cases in rural areas and urban outbreaks. Urban AVL is in active dispersion from the northeastern border of Argentina-Paraguay-Brazil to the South. The presence of Lutzomyia longipalpis was initially reported in urban environments in the northwestern border of the country. The presence of Lu. longipalpis, environmental variables associated with its distribution, and its genetic diversity were assessed in Salvador Mazza, Argentina, on the border with Bolivia. The genetic analysis showed high haplotype diversity, low nucleotide diversity, and low nucleotide polymorphism index. We discuss the hypothesis of an expanding urban population with introgressive hybridisation of older haplogroups found in their path in natural forest or rural environments, acquiring a new adaptability to urban environments, and the possibility of changes in vector capacity.

Lutzomyia longipalpis (Diptera: Psychodidae) Argentina-Bolivia border: new report and genetic diversity

American visceral leishmaniasis (AVL) has two main scenarios of transmission as follows: scattered cases in rural areas and urban outbreaks. Urban AVL is in active dispersion from the northeastern border of Argentina-Paraguay-Brazil to the South. The presence of Lutzomyia longipalpis was initially reported in urban environments in the northwestern border of the country. The presence of Lu. longipalpis, environmental variables associated with its distribution, and its genetic diversity were assessed in Salvador Mazza, Argentina, on the border with Bolivia. The genetic analysis showed high haplotype diversity, low nucleotide diversity, and low nucleotide polymorphism index. We discuss the hypothesis of an expanding urban population with introgressive hybridisation of older haplogroups found in their path in natural forest or rural environments, acquiring a new adaptability to urban environments, and the possibility of changes in vector capacity.

Respuesta doméstica a las recomendaciones sanitarias de intervención sobre ambiente y perros en una localidad con transmisión de leishmaniasis visceral (Pto. Iguazú, Argentina, 2014­2016) / Domestic response to intervention based on health recommendations on the environment and dogs in a locality with transmission of visceral leishmaniosis (Pto. Iguazú, Argentina, 2014-2016)

Introducción: La leishmaniasis visceral (LV) es una enfermedad parasitaria emergente en Argentina. En Puerto Iguazú, frontera con Brasil y Paraguay, en 2010 se registró presencia del vector y casos caninos; y en 2014-2015 dos casos humanos. Objetivo: Este artículo tiene como objetivo analizar los cambios en el nivel micro escala después de dar a conocer a los convivientes el diagnóstico de LV canina (LVC), informándoles estrategias de manejo ambiental para reducir el contacto con el vector. Método: Es una investigación descriptiva, que indagó en dos momentos (2014 y 2016) una muestra no probabilística distribuida en base al criterio de mejor escenario para la presencia del vector (n = 55) en la que se seleccionaron, luego de un primer rastrillaje entomológico y de diagnóstico veterinario, puntos de muestreo con presencia de vectores y al menos un perro con LVC (n = 6/55). Resultados: Un único hogar implementó las modificaciones sugeridas. Esos cambios no resultaron suficientes para controlar la transmisión. La hipótesis es que las medidas de control requieren intervención a meso escala (el vecindario y no el domicilio), atendiendo al radio real de dispersión de vectores. Conclusiones: El riesgo de infección humana por LV se relaciona con el modo de vida, incluyendo las relaciones interespecie. Las relaciones humano-perro combinan especismo y poshumanismo, acotando la efectividad de la "tenencia responsable" como modelo de vínculo saludable.

Introduction: Visceral leishmaniasis (VL) is an emerging parasitic disease in Argentina. In Puerto Iguazú, border with Brazil and Paraguay, vector and canine cases were registered in 2010; and in 2014 and 2015 there were two human cases. Objective: The objective of this article is to analyze changes at the micro-scale level after informing the cohabitants of the diagnosis of canine LV (LVC), letting them know the environmental management strategies to reduce contact with the vector. Method: It is a descriptive researh, which investigated in two moments (2014 and 2016) a non-probabilistic sample distributed based on the criterion of the best scenario for the presence of the vector (n = 55). Sampling points with the presence of vectors and at least one dog with LVC (n = 6/55) were selected, after a first entomological and veterinary diagnosis raking. Results: A single household implemented the suggested modifications. The changes were not enough to control the transmission. The hypothesis is that the control measures require intervention at a meso-scale (the neighborhood instead of the home), taking into account the real radius of vector dispersion. Conclusions: The risk of human infection due to VL is related to the way of life, including interspecies relationships. The human-dog relationships combine speciesism and post-humanism, which limits the effectiveness of "responsible ownership" as model of a healthy bond.

Ceratopogonidae (Diptera: Nematocera) of the piedmont of the Yungas forests of Tucumán: ecology and distribution.

Within the Ceratopogonidae family, many genera transmit numerous diseases to humans and animals, while others are important pollinators of tropical crops. In the Yungas ecoregion of Argentina, previous systematic and ecological research on Ceratopogonidae focused on Culicoides, since they are the main transmitters of mansonelliasis in northwestern Argentina; however, few studies included the genera Forcipomyia, Dasyhelea, Atrichopogon, Alluaudomyia, Echinohelea, and Bezzia. Therefore, the objective of this study was to determine the presence and abundance of Ceratopogonidae in this region, their association with meteorological variables, and their variation in areas disturbed by human activity. Monthly collection of specimens was performed from July 2008 to July 2009 using CDC miniature light traps deployed for two consecutive days. A total of 360 specimens were collected, being the most abundant Dasyhelea genus (48.06%) followed by Forcipomyia (26.94%) and Atrichopogon (13.61%). Bivariate analyses showed significant differences in the abundance of the genera at different sampling sites and climatic conditions, with the summer season and El Corralito site showing the greatest abundance of specimens. Accumulated rainfall was the variable that related the most to the abundance of Culicoides (10.56%), while temperature was the most closely related variable to the abundance of Forcipomyia, Dasyhelea, and Atrichopogon.

Lutzomyia longipalpis urbanisation and control

Since the description of Lutzomyia longipalpis by Lutz and Neiva more than 100 years ago, much has been written in the scientific literature about this phlebotomine species. Soares and Turco (2003) and Lainson and Rangel (2005) have written extensive reviews focused on vector-host-parasite interactions and American visceral leishmaniasis ecology. However, during the last two decades, the success of Lu. longipalpis in colonising urban environments and its simultaneous geographical spreading have led to new theoretical and operational questions. Therefore, this review updates the general information about this species and notes the more challenging topics regarding the new scenario of urbanisation-spreading and its control in America. Here, we summarise the literature on these issues and the remaining unsolved questions, which pose recommendations for operational research.

Lutzomyia longipalpis urbanisation and control.

Since the description of Lutzomyia longipalpis by Lutz and Neiva more than 100 years ago, much has been written in the scientific literature about this phlebotomine species. Soares and Turco (2003) and Lainson and Rangel (2005) have written extensive reviews focused on vector-host-parasite interactions and American visceral leishmaniasis ecology. However, during the last two decades, the success of Lu. longipalpis in colonising urban environments and its simultaneous geographical spreading have led to new theoretical and operational questions. Therefore, this review updates the general information about this species and notes the more challenging topics regarding the new scenario of urbanisation-spreading and its control in America. Here, we summarise the literature on these issues and the remaining unsolved questions, which pose recommendations for operational research.

The first record of Lutzomyia longipalpis in the Argentine northwest.

In 2004, the urban presence of Lutzomyia longipalpis was recorded for the first time in Formosa province. In 2006, the first autochthonous case of human urban visceral leishmaniasis (VL) was recorded in Misiones in the presence of the vector, along with some canine VL cases. After this first case, the vector began to spread primarily in northeast Argentina. Between 2008-2011, three human VL cases were reported in Salta province, but the presence of Lu. longipalpis was not recorded. Captures of Phlebotominae were made in Tartagal, Salta, in 2013, and the presence of Lu. longipalpis was first recorded in northwest Argentina at that time. Systematic sampling is recommended to observe the distribution and dispersion patterns of Lu. longipalpis and consider the risk of VL transmission in the region.

Leishmaniasis and climate change-case study: Argentina.

Vector-borne diseases closely associated with the environment, such as leishmaniases, have been a usual argument about the deleterious impact of climate change on public health. From the biological point of view interaction of different variables has different and even conflicting effects on the survival of vectors and the probability transmission of pathogens. The results on ecoepidemiology of leishmaniasis in Argentina related to climate variables at different scales of space and time are presented. These studies showed that the changes in transmission due to change or increase in frequency and intensity of climatic instability were expressed through changes in the probability of vector-human reservoir effective contacts. These changes of contact in turn are modulated by both direct effects on the biology and ecology of the organisms involved, as by perceptions and changes in the behavior of the human communities at risk. Therefore, from the perspective of public health and state policy, and taking into account the current nonlinear increased velocity of climate change, we concluded that discussing the uncertainties of large-scale models will have lower impact than to develop-validate mitigation strategies to be operative at local level, and compatibles with sustainable development, conservation biodiversity, and respect for cultural diversity.

Distribution and abundance of phlebotominae, vectors of leishmaniasis, in Argentina: spatial and temporal analysis at different scales.

The spatial-temporal analysis of the abundance of insects, vectors of tegumentary leishmaniasis (TL) and visceral leishmaniasis (VL), was performed in Argentina using spatial-temporal increasing scales. In the microscale (microfocal), the effect of the primary vegetation-crop interface in vector abundance was observed, and also how the shelters, food sources, and other environmental characteristics contribute to habitat microheterogeneity and so to a microheterogeneous vector distribution. In the mesoscale (locality or epidemic focus), the results from different foci of TL (rural and periurban) and VL (urban) suggested a metapopulation structure determined partially by quantifiable habitat variables that could explain the increase of risk associated to an increase of vector-human contact due to climatic or anthropogenic changes. In the macroscale (regional), captures of vectors and records of human cases allowed the construction of risk maps and predictive models of vector distribution. In conclusion, in order to obtain valid results transferrable to control programs from spatial studies, special attention should be paid in order to assure the consistency between the spatial scales of the hypotheses, data, and analytical tools of each experimental or descriptive design.

Hourly activity of Lutzomyia neivai in the endemic zone of cutaneous leishmaniasis in Tucumán, Argentina: preliminary results.

In the present work, the hourly activity of Lutzomyia neivai was studied in the southern part of the province of Tucumán, Argentina, in an area of transmission of cutaneous leishmaniasis during two months of higher activity. In addition, the variables that influenced the abundance of Lu. neivai were evaluated. A total of 1,146 individuals belonging to Lu. neivai (97%) and Lutzomyia migonei (3%) were captured. The hourly activity of Lu. neivai was mainly nocturnal, with a bimodal pattern in both months. In January, the variable that most influenced the abundance of Lu. neivai was the temperature, whereas in April, that variable was humidity. These results may contribute to the design of anti-vectorial control measures at a micro-focal scale.

Hourly activity of Lutzomyia neivai in the endemic zone of cutaneous leishmaniasis in Tucumán, Argentina: preliminary results

In the present work, the hourly activity of Lutzomyia neivai was studied in the southern part of the province of Tucumán, Argentina, in an area of transmission of cutaneous leishmaniasis during two months of higher activity. In addition, the variables that influenced the abundance of Lu. neivai were evaluated. A total of 1,146 individuals belonging to Lu. neivai (97 percent) and Lutzomyia migonei (3 percent) were captured. The hourly activity of Lu. neivai was mainly nocturnal, with a bimodal pattern in both months. In January, the variable that most influenced the abundance of Lu. neivai was the temperature, whereas in April, that variable was humidity. These results may contribute to the design of anti-vectorial control measures at a micro-focal scale.

Distribución de vectores de leishmaniasis visceral en la Provincia de Corrientes, 2008 / Distribution of vectors of visceral leishmaniasis in the Province of Corrientes, 2008

La leishmaniasis visceral es una parasitosis de importancia en salud pública, producida por Leishmania infantum chagasi. A partir de la urbanización y emergencia en el sur de Brasil y Paraguay, se notificó la presencia del insecto vector Lutzomyia longipalpis en la Argentina; en Formosa, 2004, y en Misiones el primer caso humano en 2006. La notificación de casos de reservorios caninos infectados en la provincia de Corrientes, contigua a Misiones, determinó la búsqueda del vector. Mediante trampeos estandarizados en diciembre del 2008 se capturaron 376 Lu. longipalpis en Ituzaingó, Virasoro, Santo Tomé, Garruchos, Riachuelo, Corrientes y Monte Caseros. Se confirma el riesgo de transmisión vectorial autóctona de leishmaniasis visceral en la provincia de Corrientes. La distribución de vectores en áreas urbanas densamente pobladas, con intenso tránsito de reservorios caninos desde zonas de alta transmisión, y la presencia de reservorios infectados, implica a su vez riesgo epidémico.

Visceral leishmaniasis (VL) is a relevant parasitic disease in public health, produced by Leishmania infantum chagasi. Since the urbanization and emergence in Southern Brazil and Paraguay, the vector Lutzomyia longipalpis in Formosa, 2004, and the first human visceral leishmaniasis case in Misiones, 2006, have been reported in Argentina. Due to the reports of canine VL, a search of the vector in the Province of Corrientes, contiguous to Misiones, was performed during December 2008. Standarized trapping detected 376 Lu. longipalpis in Ituzaingó, Virasoro, Santo Tomé, Garruchos, Riachuelo, Corrientes and Monte Caseros localities. The risk of autochtonous vectorial transmission was then confirmed in the Province of Corrientes. The distribution of vectors in populated urban areas, with intense transit of canine reservoirs from localities with high transmission, and the existence of infected reservoirs, also implies epidemic risk.

[Distribution of vectors of visceral leishmaniasis in the Province of Corrientes, 2008]. / Distribución de vectores de leishmaniasis visceral en la Provincia de Corrientes, 2008.

Visceral leishmaniasis (VL) is a relevant parasitic disease in public health, produced by Leishmania infantum chagasi. Since the urbanization and emergence in Southern Brazil and Paraguay, the vector Lutzomyia longipalpis in Formosa, 2004, and the first human visceral leishmaniasis case in Misiones, 2006, have been reported in Argentina. Due to the reports of canine VL, a search of the vector in the Province of Corrientes, contiguous to Misiones, was performed during December 2008. Standarized trapping detected 376 Lu. longipalpis in Ituzaingó, Virasoro, Santo Tomé, Garruchos, Riachuelo, Corrientes and Monte Caseros localities. The risk of autochtonous vectorial transmission was then confirmed in the Province of Corrientes. The distribution of vectors in populated urban areas, with intense transit of canine reservoirs from localities with high transmission, and the existence of infected reservoirs, also implies epidemic risk.