Indigenous ecological calendars and seasonal vector-borne diseases in the Colombian Amazon: an intercultural and interdisciplinary approach / Calendarios ecológicos indígenas y enfermedades estacionales transmitidas por vectores en la Amazonia colombiana: un enfoque intercultural e interdisciplinario

Traditional ecological knowledge of indigenous groups in the southeastern Colombian Amazon coincides in identifying the two main hydrological transition periods (wet-dry: August-November; dry-wet: March-April) as those with greater susceptibility to disease in humans. Here we analyze the association between indigenous knowledge about these two periods and the incidence of two vector-borne diseases: malaria and dengue. We researched seven "ecological calendars" from three regions in the Colombian Amazon, malaria and dengue cases reported from 2007 to 2019 by the Colombian National Institute of Health, and daily temperature and precipitation data from eight meteorological stations in the region from 1990-2019 (a climatological normal). Malaria and dengue follow a seasonal pattern: malaria has a peak from August to November, corresponding with the wet-dry transition (the "season of the worms" in the indigenous calendars), and dengue has a peak in March and April, coinciding with the dry-wet transition. Previous studies have shown a positive correlation between rainfall and dengue and a negative correlation between rainfall and malaria. However, as the indigenous ecological knowledge codified in the calendars suggests, disease prediction cannot be reduced to a linear correlation with a single environmental variable. Our data show that two major aspects of the indigenous calendars (the time of friaje as a critical marker of the year and the hydrological transition periods as periods of greater susceptibility to diseases) are supported by meteorological data and by the available information about the incidence of malaria and dengue.(AU)

Los conocimientos ecológicos tradicionales de grupos indígenas del sureste de la Amazonia colombiana coinciden en identificar dos principales periodos de transición hidrológica (seco-húmedo: agosto-noviembre; húmedo-seco: marzo-abril) como los de mayor susceptibilidad a enfermedades en humanos. Aquí analizamos la asociación entre el conocimiento indígena sobre estos dos periodos y la incidencia de dos enfermedades transmitidas por vectores: malaria y dengue. Investigamos siete calendarios ecológicos de tres regiones en la Amazonia colombiana, casos de dengue y malaria reportados de 2007 hasta 2019 por el Instituto Nacional de Salud de Colombia y datos diarios de temperatura y precipitación de ocho estaciones meteorológicas en la región, de 1990 a 2019 (una normal climatológica). Malaria y dengue siguen un patrón estacional, la malaria tiene un pico de agosto a noviembre, correspondiendo con la transición húmedo-seco (el "tiempo de gusano" según los calendarios indígenas), mientras que dengue tiene un pico de marzo a abril, coincidiendo con la transición seco-húmedo. Estudios previos mostraron una correlación positiva entre precipitación y dengue, y una correlación negativa entre precipitación y malaria. Sin embargo, como lo sugiere el conocimiento ecológico codificado en los calendarios indígenas, la predicción de enfermedades no puede reducirse a una correlación lineal con una sola variable medioambiental. Nuestros datos muestran que dos aspectos principales de los calendarios indígenas (el tiempo de friaje como un marcador crítico anual y los periodos de transición hidrológica como épocas de mayor susceptibilidad a enfermedades) están soportados por datos meteorológicos e información disponible acerca de la incidencia de malaria y dengue.(AU)

Mixed species flock, nest height, and elevation partially explain avian haemoparasite prevalence in Colombia.

The high avian biodiversity present in the Neotropical region offers a great opportunity to explore the ecology of host-parasite relationships. We present a survey of avian haemoparasites in a megadiverse country and explore how parasite prevalences are related to physical and ecological host characteristics. Using light microscopy, we documented the presence of haemoparasites in over 2000 individuals belonging to 246 species of wild birds, from nine localities and several ecosystems of Colombia. We analysed the prevalence of six avian haemoparasite taxa in relation to elevation and the following host traits: nest height, nest type, foraging strata, primary diet, sociality, migratory behaviour, and participation in mixed species flocks. Our analyses indicate significant associations between both mixed species flocks and nest height and Haemoproteus and Leucocytozoon prevalence. The prevalence of Leucocytozoon increased with elevation, whereas the prevalence of Trypanosoma and microfilariae decreased. Plasmodium and Haemoproteus prevalence did not vary significantly with elevation; in fact, both parasites were found up to 3300 m above sea level. The distribution of parasite prevalence across the phylogeny of bird species included in this study showed little host phylogenetic signal indicating that infection rates in this system are evolutionarily labile. Vector distribution as well as the biology of transmission and the maintenance of populations of avian haemoparasites deserve more detailed study in this system.