The risk of vector transmission of Trypanosoma cruzi remains high in the State of Paraná

BACKGROUND Monitoring and analysing the infection rates of the vector of Trypanosoma cruzi, that causes Chagas disease, helps assess the risk of transmission. OBJECTIVES A study was carried out on triatomine in the State of Paraná, Brazil, between 2012 and 2021 and a comparison was made with a previous study. This was done to assess the risk of disease transmission. METHODS Ecological niche models based on climate and landscape variables were developed to predict habitat suitability for the vectors as a proxy for risk of occurrence. FINDINGS A total of 1,750 specimens of triatomines were recorded, of which six species were identified. The overall infection rate was 22.7%. The areas with the highest risk transmission of T. cruzi are consistent with previous predictions in municipalities. New data shows that climate models are more accurate than landscape models. This is likely because climate suitability was higher in the previous period. MAIN CONCLUSION Regardless of uneven sampling and potential biases, risk remains high due to the wide presence of infected vectors and high environmental suitability for vector species throughout the state and, therefore, improvements in public policies aimed at wide dissemination of knowledge about the disease are recommended to ensure the State remains free of Chagas disease.

The relationship between forest fragmentation and the potential geographical distribution of psittacids (Psittaciformes: Psittacidae) in the Yucatán Peninsula, Mexico / Relación entre la fragmentación forestal y la distribución geográfica potencial de los psitácidos (Psittaciformes: Psittacidae) en la Península de Yucatán, México

Abstract Parrots are a seriously threatened group because of the illegal pet trade, their habitat fragmentation and the destruction of tropical forests. This study aimed to determine the relationship between forest fragmentation and the geographic potential distribution of parrot species in the Yucatan Peninsula, Mexico. The research was carried out in the Mexican portion of the Yucatan Peninsula Biotic region, which includes the states of Campeche, Quintana Roo and Yucatan. We worked with the eight species of psittacids that inhabit the selected areas: Eupsittula nana, Amazona albifrons, Amazona xantholora, Amazona autumnalis, Pionus senilis, Pyrilia haematotis, Amazona oratrix and Amazona farinosa. For these species, we used the potential geographical distribution maps that were obtained through the Maximum Entropy algorithm, published in 2014. To measure the levels of forest fragmentation in the Peninsula, we employed the land use and vegetation maps from series IV (2007-2010) of the National Institute of Statistics and Geography. We calculated different landscape metrics at 100 sites randomly distributed within the predicted presence and absence areas for the species. Multivariate methods were used to shorten dimensionality in the analysis, as well as to explore the observed patterns. We did not find any pattern regarding the number of variables that contribute to the logistic regression models (LR) and the size of the parrots' potential geographical distribution area within the Peninsula. For Pyrilia haematotis and Amazona oratrix, the fragmentation variables used did not seem to have any relationship with their potential geographical distribution in the Peninsula (intersection, Pr<0.0001). Only for Eupsittula nana, Amazona xantholora and Pionus senilis, we found that the mean patch edge, the mean shape index and the mean perimeterarea ratio were important to determine their potential distribution patterns, respectively; and, in general, the variables indicated the preferences of these parrots to occupy larger habitat patches. Parrots must be given a special care and protection within the states of Campeche and Quintana Roo, since there are areas with high parrot diversity and are importantly affected by human activities. The best recommendation for managers and users of protected areas within the Yucatan Peninsula is that extensive areas of forest should be maintained in order to guarantee the suvival of psittacid populations.

Resumen Los psitácidos se encuentran seriamente amenazados por el tráfico ilegal de mascotas y la destruc ción y fragmentación de su hábitat. El objetivo de este estudio fue determinar la relación entre la fragmentación y los patrones de distribución geográfica potencial de las especies de psitácidos de la Península de Yucatán, México. El estudio se realizó en la porción mexicana de la Provincia Biótica Península de Yucatán, que incluye los estados de Campeche, Quintana Roo y Yucatán. Se estudiaron las ocho especies de psitácidos que habitan la Península de Yucatán: Eupsittula nana, Amazona albifrons, Amazona xantholora, Amazona autumnalis, Pionus senilis, Pyrilia haematotis, Amazona oratrix y Amazona farinosa. Para las ocho especies se utilizaron los mapas de distribución geográfica potencial publicados en la literatura en el 2014, obtenidos con el algoritmo de máxima entropía (MaxEnt). Los mapas de uso de suelo y vegetación de la serie IV (2007-2010) del Instituto Nacional de Geografía y Estadística se usaron para medir los niveles de fragmentación de las selvas en la Península de Yucatán. Se calcularon diferentes métricas del paisaje en 100 parcelas distribuidas al azar dentro de las áreas de presencia y ausencia predichas para las especies. Se emplearon métodos multivariados para reducir dimensionalidad en los análisis, así como para explorar los patrones observados. No se encontró ningún patrón en cuanto al número de variables que aportan a los modelos de regresión logística (RL) y el tamaño del área de distribución geográfica potencial de los loros en la Península. Para Pyrilia haematotis y Amazona oratrix, la escala de trabajo con las variables de fragmentación, no parecen tener relación con su distribución geográfica potencial en la Península (intersección, Pr<0.0001). Solo para Eupsittula nana, Amazona xantholora y Pionus senilis secomprobó que la media del borde del fragmento, el índice medio de forma y la media de la proporción área-perímetro son importantes para determinar sus patrones de distribución respectivamente y en general apuntan una preferencia de estos loros por ocupar sitios que conservan fragmentos grandes de vegetación. Se le debe prestar mucha atención a la protección de los psitácidos en los estados de Campeche y Quintana Roo por ser áreas con una alta diversidad de loros y una zona altamente impactada por las actividades humanas. La recomendación más importante para los administradores y usuarios de las áreas protegidas dentro de la Península de Yucatán es que se deben mantener extensas áreas forestales para garantizar así la persistencia de las poblaciones de psitácidos.

Atlas of Mexican Triatominae (Reduviidae: Hemiptera) and vector transmission of Chagas disease

Chagas disease is one of the most important yet neglected parasitic diseases in Mexico and is transmitted by Triatominae. Nineteen of the 31 Mexican triatomine species have been consistently found to invade human houses and all have been found to be naturally infected with Trypanosoma cruzi. The present paper aims to produce a state-of-knowledge atlas of Mexican triatomines and analyse their geographic associations with T. cruzi, human demographics and landscape modification. Ecological niche models (ENMs) were constructed for the 19 species with more than 10 records in North America, as well as for T. cruzi. The 2010 Mexican national census and the 2007 National Forestry Inventory were used to analyse overlap patterns with ENMs. Niche breadth was greatest in species from the semiarid Nearctic Region, whereas species richness was associated with topographic heterogeneity in the Neotropical Region, particularly along the Pacific Coast. Three species, Triatoma longipennis, Triatoma mexicana and Triatoma barberi, overlapped with the greatest numbers of human communities, but these communities had the lowest rural/urban population ratios. Triatomine vectors have urbanised in most regions, demonstrating a high tolerance to human-modified habitats and broadened historical ranges, exposing more than 88% of the Mexican population and leaving few areas in Mexico without the potential for T. cruzi transmission.

Caracterización del área de distribución geográfica potencial de las especies de aves psitácidas de la Península de Yucatán, México / Characterization of the potential geographical distribution area of parrot species in Yucatan Peninsula, Mexico

Psittacidae family is one of the most endangered groups in Mexico, since many of their habitats are disappearing. In this research, we characterized the land cover of the potential geographical distribution area of eight extant parrot species within the Yucatan Peninsula. We used the Maximum Entropy algorithm (MaxEnt) and species historical records. To externally validate the models, we used presence and absence records from field observations (2010-2012). To characterize the distribution area, we used the vegetation and land use maps of INEGI Series IV (2007-2010). The models showed a good performance, according to the values of the area under the curve (AUC), which ranged between 0.88-0.95 with the training data and between 0.82-0.91 with test data. We located most of the species in sites where the models predicted their presence. In the Peninsula, over 76% of the parrots’ potential geographical distribution area is forested, except for Amazona oratrix. The subhumid tropical forest is the best represented, and the livestock for land use. The most affected species within the Peninsula are: Amazona farinosa and A. oratrix. The Calakmul Biosphere Reserve is the most important area for parrots’ protection in the Peninsula. Knowing the characteristics of distribution areas is an essential part in the establishment of parrots’ conservation strategies. Rev. Biol. Trop. 62 (4): 1509-1522. Epub 2014 December 01.

La familia Psittacidae es una de las más amenazadas en México y los hábitats donde se distribuyen desaparecen. En este estudio se caracterizó la cobertura del suelo del área de distribución geográfica potencial de las ocho especies de psitácidos presentes en la Península de Yucatán. Se utilizó el algoritmo de Máxima Entropía (MaxEnt) y registros históricos de las especies. Para validar externamente los modelos se utilizaron registros de presencia y ausencia tomados en campo (2010-2012). Para caracterizar el área de distribución se utilizó la carta de uso de suelo y vegetación Serie IV de INEGI (2007-2010). Los modelos tuvieron un buen desempeño, de acuerdo a los valores del área bajo la curva (AUC), que oscilaron entre 0.88-0.95 con los datos de entrenamiento y entre 0.82-0.91 con los de prueba. Se localizó a la mayoría de las especies en los sitios donde los modelos predecían presencia. Más del 76% del área de distribución geográfica potencial de los psitácidos en la Península está ocupada por selva, excepto para Amazona oratrix. La selva mediana subperennifolia es la mejor representada en las áreas de distribución y de los usos de suelo el mejor representado es el pecuario. La especies más afectadas dentro de la Península son: Amazona farinosa y A. oratrix. La Reserva de la Biosfera de Calakmul es la más importante para la protección de los psitácidos en la Península. El conocimiento de las características de las áreas de distribución es parte fundamental en el establecimiento de estrategias de conservación de los psitácidos.