Allatotropin-like peptide released by Malpighian tubules induces hindgut activity associated with diuresis in the Chagas disease vector Triatoma infestans (Klug)

Haematophagous insects incorporate a large amount of blood with each meal, producing a big quantity of urine in a few hours to eliminate the excess water and Na+. Malpighian tubules (MTs) have traditionally been seen as a system that responds to neuroendocrine stimulus. In a related paper, we demonstrated that MTs of Triatoma infestans produce an autonomous endocrine secretion of an allatotropin-like (AT-like) peptide. In the present study, we report a myostimulatory activity of AT at the level of the hindgut (HG), associated with endocrine mechanisms regulating post-prandial diuresis. Allatotropin induced an increase in frequency and intensity of peristaltic contractions at the level of the HG. The release of the HG content in MTs-HG in vitro preparations undergoing an osmotic shock occurred at different times, depending on the number of MTs present, and there was no release in treatments without MTs. The application of an AT-antiserum to MTs-HG preparations undergoing osmotic shock produced a delay or a long-term blockade of diuresis, depending on the antiserum dilution applied. Similar results were obtained when AT-antiserum was applied in vivo prior to blood intake, decreasing the volume of urine eliminated during the first 2 h. Our results allow us to assign a specific endocrine function to the AT-like peptide released by MTs that is linked to the elimination of urine after blood meals.Facultad de Ciencias Naturales y Muse

Allatotropin-like peptide released by Malpighian tubules induces hindgut activity associated with diuresis in the Chagas disease vector Triatoma infestans (Klug)

Haematophagous insects incorporate a large amount of blood with each meal, producing a big quantity of urine in a few hours to eliminate the excess water and Na+. Malpighian tubules (MTs) have traditionally been seen as a system that responds to neuroendocrine stimulus. In a related paper, we demonstrated that MTs of Triatoma infestans produce an autonomous endocrine secretion of an allatotropin-like (AT-like) peptide. In the present study, we report a myostimulatory activity of AT at the level of the hindgut (HG), associated with endocrine mechanisms regulating post-prandial diuresis. Allatotropin induced an increase in frequency and intensity of peristaltic contractions at the level of the HG. The release of the HG content in MTs-HG in vitro preparations undergoing an osmotic shock occurred at different times, depending on the number of MTs present, and there was no release in treatments without MTs. The application of an AT-antiserum to MTs-HG preparations undergoing osmotic shock produced a delay or a long-term blockade of diuresis, depending on the antiserum dilution applied. Similar results were obtained when AT-antiserum was applied in vivo prior to blood intake, decreasing the volume of urine eliminated during the first 2 h. Our results allow us to assign a specific endocrine function to the AT-like peptide released by MTs that is linked to the elimination of urine after blood meals.Facultad de Ciencias Naturales y Muse

Coronavirus, jaque a la ciencia y la salud

La pandemia ocasionada por el virus SARS-CoV2 puso al mundo en jaque, y la Argentina no es la excepción. SARS-CoV2 es el séptimo miembro de la familia de los Coronavirus que infecta a humanos y genera una problemática sanitaria conocida como COVID-19. Si bien el caso índice mundial fue denunciado en diciembre de 2019 en China, a 19.186 km de distancia de nuestro país, el primer caso importado identificado en Argentina fue el 5 de marzo de 2020. El informe diario del Ministerio de Salud de la Nación del 12 de marzo ya denunciaba los primeros casos ocurridos por contacto estrecho con viajeros y para finales del mismo mes se denunció el primer caso de transmisión comunitaria. Independientemente del nivel de análisis desde donde se estudie esta pandemia, surgen dudas, se identifican baches, que incluso nos invitan a repensarnos como sistemas socio-ambientales, socio-económicos, sociosanitarios, tanto desde una perspectiva mundial como regional.Asociación Parasitológica Argentin

Update on the distribution of Aedes albopictus (Diptera: Culicidae) in Misiones, Argentina

The Asian tiger mosquito (Aedes albopictus, Diptera: Culicidae) has spread rapidly in the last 30 years from its native region in Southeast Asia. In Argentina, studies on its potential distribution suggest that this species could be found in temperate zones of the province of Buenos Aires. However, since its initial detection in 1998 Ae. albopictus is bounded to the subtropical province of Misiones. To evaluate the presence and abundance of Ae. albopictus in the Northeast of Argentina, we preliminarily evaluated the presence of this vector by analyzing its presence in tires of 20 cities belonging to the province of Misiones and four cities in Northern Corrientes, and then performed an evaluation of the vector in the towns where the vector was detected. Aedes albopictus was present only in two cities of Misiones: Eldorado and Colonia Aurora. Aedes aegypti and Ae. albopictus accounted for 86% of the individuals collected in the domiciles of both towns. In Colonia Aurora both species were in similar abundances suggesting a co-dominance. The present study extends the austral distribution of Ae. albopictus in Argentina to the city of Colonia Aurora where the highest abundance recorded in Argentina was detected. Nevertheless, the reasons of its bounded distribution in the region are not known

Allatotropin-like peptide released by Malpighian tubules induces hindgut activity associated with diuresis in the Chagas disease vector Triatoma infestans (Klug)

Haematophagous insects incorporate a large amount of blood with each meal, producing a big quantity of urine in a few hours to eliminate the excess water and Na+. Malpighian tubules (MTs) have traditionally been seen as a system that responds to neuroendocrine stimulus. In a related paper, we demonstrated that MTs of Triatoma infestans produce an autonomous endocrine secretion of an allatotropin-like (AT-like) peptide. In the present study, we report a myostimulatory activity of AT at the level of the hindgut (HG), associated with endocrine mechanisms regulating post-prandial diuresis. Allatotropin induced an increase in frequency and intensity of peristaltic contractions at the level of the HG. The release of the HG content in MTs-HG in vitro preparations undergoing an osmotic shock occurred at different times, depending on the number of MTs present, and there was no release in treatments without MTs. The application of an AT-antiserum to MTs-HG preparations undergoing osmotic shock produced a delay or a long-term blockade of diuresis, depending on the antiserum dilution applied. Similar results were obtained when AT-antiserum was applied in vivo prior to blood intake, decreasing the volume of urine eliminated during the first 2 h. Our results allow us to assign a specific endocrine function to the AT-like peptide released by MTs that is linked to the elimination of urine after blood meals.Facultad de Ciencias Naturales y Muse

Psychodidae, Subfamilia Phlebotominae

Los flebótomos son dípteros nematóceros de la familia Psychodidae, subfamilia Phlebotominae. Son un grupo de insectos que tiene una amplia distribución mundial con excepción de Nueva Zelanda e Islas del Pacífico. Sólo los que viven en áreas tropicales pueden realizar su ciclo vital completo durante todo el año, mientras que los que viven en las regiones subtropicales solo lo pueden completar durante los meses cálidos. Se los encuentra en un amplio rango de hábitats desde selva húmeda hasta regiones muy áridas, desde el nivel del mar hasta altitudes de 2800 metros; sin embargo, cada especie presenta requerimientos ecológicos específicos. De las aproximadamente 700 especies conocidas en el mundo, cerca de 70 están involucradas en ciclos de transmisión de patógenos al ser humano. El nombre común en inglés “sand fly” (cuya traducción literal es “moscas de arena”) deriva del estudio de flebótomos de las regiones más áridas del continente europeo, aunque son muy comunes en las regiones húmedas tropicales y subtropicales.Facultad de Ciencias Naturales y Muse

First Comparative Transcriptomic Analysis of Wild Adult Male and Female Lutzomyia longipalpis, Vector of Visceral Leishmaniasis

Leishmaniasis is a vector-borne disease with a complex epidemiology and ecology. Visceral leishmaniasis (VL) is its most severe clinical form as it results in death if not treated. In Latin America VL is caused by the protist parasite Leishmania infantum (syn. chagasi) and transmitted by Lutzomyia longipalpis. This phlebotomine sand fly is only found in the New World, from Mexico to Argentina. However, due to deforestation, migration and urbanisation, among others, VL in Latin America is undergoing an evident geographic expansion as well as dramatic changes in its transmission patterns. In this context, the first VL outbreak was recently reported in Argentina, which has already caused 7 deaths and 83 reported cases. Insect vector transcriptomic analyses enable the identification of molecules involved in the insect's biology and vector-parasite interaction. Previous studies on laboratory reared Lu. longipalpis have provided a descriptive repertoire of gene expression in the whole insect, midgut, salivary gland and male reproductive organs. Nevertheless, the study of wild specimens would contribute a unique insight into the development of novel bioinsecticides. Given the recent VL outbreak in Argentina and the compelling need to develop appropriate control strategies, this study focused on wild male and female Lu. longipalpis from an Argentine endemic (Posadas, Misiones) and a Brazilian non-endemic (Lapinha Cave, Minas Gerais) VL location. In this study, total RNA was extracted from the sand flies, submitted to sequence independent amplification and high-throughput pyrosequencing. This is the first time an unbiased and comprehensive transcriptomic approach has been used to analyse an infectious disease vector in its natural environment. Transcripts identified in the sand flies showed characteristic profiles which correlated with the environment of origin and with taxa previously identified in these same specimens. Among these, various genes represented putative targets for vector control via RNA interference (RNAi).Facultad de Ciencias Exacta

Peridomestic natural breeding sites of Nyssomyia whitmani (Antunes and Coutinho) in an endemic area of tegumentary leishmaniasis in northeastern Argentina

The scarce information about breeding sites of phlebotomines limits our understanding of the epidemiology of tegumentary leishmaniasis. Identifying the breeding sites and seasons of immature stages of these vectors is essential to propose prevention and control strategies different from those targeting the adult stage. Here we identified the rural breeding environments of immature stages of Ny. whitmani, vector species of Leishmania braziliensis in the north of Misiones province, Argentina; then we determined and compared the environmental and structural characteristics of those sites. We also identified the season of greatest emergence and its relationship with adult abundance. During a first collection period, between 28 and 48 emergence traps were set continuously for 16 months in six environments of the farm peridomicile and domicile: below house, chicken shed, experimental chicken shed, forest edge, pigsty and under fruit tree. Traps were checked and rotated every 40 nights. A total of 146 newly emerged individuals were collected (93.8% of them were Ny. whitmani), totaling an effort of 23,040 emergence trap-nights. The most productive environments were chicken shed and below house, and the greatest emergence was recorded in spring and summer. During a second collection period, emergence traps and light traps for adult cap-ture were placed in the chicken shed and below house environments of eight farms. Emergence traps were active continuously during spring, summer, and early autumn. Environmental and structural characteristics of each environment were recorded. A total of 84 newly emerged phlebotomines (92.9% Ny. whitmani; 72,144 emergence trap-nights) and 13,993 adult phlebotomines (147 light trap-nights) were recorded in the chicken shed and below house environments. A positive correlation was also observed between trap success of newly emerged phlebotomines and of adults after 120 days. A high spatial variability was observed in the emergence of Ny. whitmani, with the number of newly emerged individuals being highest in soils of chicken sheds with the highest number of chickens and closest to forest edge. Moreover, below house was found to be as important as chicken sheds as breeding sites of Ny. whitmani. Management of the number of chickens in sheds, soil mois-ture and pH, and the decision of where to localize the chicken sheds in relation to the houses and the forest edge, might contribute to reduce the risk of human vector exposure and transmission of Leishmania.Fil: Manteca Acosta, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Cavia, Regino. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Utgés, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Salomón, Oscar Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Medicina Tropical; ArgentinaFil: Santini, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; Argentin

Peridomestic natural breeding sites of Nyssomyia whitmani (Antunes and Coutinho) in an endemic area of tegumentary leishmaniasis in northeastern Argentina

The scarce information about breeding sites of phlebotomines limits our understanding of the epidemiology of tegumentary leishmaniasis. Identifying the breeding sites and seasons of immature stages of these vectors is essential to propose prevention and control strategies different from those targeting the adult stage. Here we identified the rural breeding environments of immature stages of Ny. whitmani, vector species of Leishmania braziliensis in the north of Misiones province, Argentina; then we determined and compared the environmental and structural characteristics of those sites. We also identified the season of greatest emergence and its relationship with adult abundance. During a first collection period, between 28 and 48 emergence traps were set continuously for 16 months in six environments of the farm peridomicile and domicile: below house, chicken shed, experimental chicken shed, forest edge, pigsty and under fruit tree. Traps were checked and rotated every 40 nights. A total of 146 newly emerged individuals were collected (93.8% of them were Ny. whitmani), totaling an effort of 23,040 emergence trap-nights. The most productive environments were chicken shed and below house, and the greatest emergence was recorded in spring and summer. During a second collection period, emergence traps and light traps for adult cap-ture were placed in the chicken shed and below house environments of eight farms. Emergence traps were active continuously during spring, summer, and early autumn. Environmental and structural characteristics of each environment were recorded. A total of 84 newly emerged phlebotomines (92.9% Ny. whitmani; 72,144 emergence trap-nights) and 13,993 adult phlebotomines (147 light trap-nights) were recorded in the chicken shed and below house environments. A positive correlation was also observed between trap success of newly emerged phlebotomines and of adults after 120 days. A high spatial variability was observed in the emergence of Ny. whitmani, with the number of newly emerged individuals being highest in soils of chicken sheds with the highest number of chickens and closest to forest edge. Moreover, below house was found to be as important as chicken sheds as breeding sites of Ny. whitmani. Management of the number of chickens in sheds, soil mois-ture and pH, and the decision of where to localize the chicken sheds in relation to the houses and the forest edge, might contribute to reduce the risk of human vector exposure and transmission of Leishmania.Fil: Manteca Acosta, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Cavia, Regino. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Utgés, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Salomón, Oscar Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Medicina Tropical; ArgentinaFil: Santini, Maria Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; Argentin

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.Fil: Santini, Maria Soledad. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán". Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cavia, Regino. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Quintana, María Gabriela. Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Medicina Tropical; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Manteca Acosta, Mariana. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Centro Nacional de Diagnóstico e Investigaciones Endemo-epidémicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Salomón, Oscar Daniel. Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán". Instituto Nacional de Medicina Tropical; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin