Background Trypanosoma cruzi is the causative agent of Chagas disease. Due to its genetic diversity has been classified into six Discrete Typing Units (DTUs) in association with transmission cycles. In Colombia, natural T. cruzi infection has been detected in 15 triatomine species. There is scarce information regarding the infection rates, DTUs and feeding preferences of secondary vectors. Therefore, the aim of this study was to determine T. cruzi infection rates, parasite DTU, ecotopes, insect stages, geographical location and bug feeding preferences across six different triatomine species.MethodsA total of 245 insects were collected in seven departments of Colombia. We conducted molecular detection and genotyping of T. cruzi with subsequent identification of food sources. The frequency of infection, DTUs, TcI genotypes and feeding sources were plotted across the six species studied. A logistic regression model risk was estimated with insects positive for T. cruzi according to demographic and eco-epidemiological characteristics.ResultsWe collected 85 specimens of Panstrongylus geniculatus, 77 Rhodnius prolixus, 37 R. pallescens, 34 Triatoma maculata, 8 R. pictipes and 4 T. dimidiata. The overall T. cruzi infection rate was 61.2% and presented statistical associations with the departments Meta (OR: 2.65; 95% CI: 1.69–4.17) and Guajira (OR: 2.13; 95% CI: 1.16–3.94); peridomestic ecotope (OR: 2.52: 95% CI: 1.62–3.93); the vector species P. geniculatus (OR: 2.40; 95% CI: 1.51–3.82) and T. maculata (OR: 2.09; 95% CI: 1.02–4.29); females (OR: 2.05; 95% CI: 1.39–3.04) and feeding on opossum (OR: 3.15; 95% CI: 1.85–11.69) and human blood (OR: 1.55; 95% CI: 1.07–2.24). Regarding the DTUs, we observed TcI (67.3%), TcII (6.7%), TcIII (8.7%), TcIV (4.0%) and TcV (6.0%). Across the samples typed as TcI, we detected TcIDom (19%) and sylvatic TcI (75%). The frequencies of feeding sources were 59.4% (human blood); 11.2% (hen); 9.6% (bat); 5.6% (opossum); 5.1% (mouse); 4.1% (dog); 3.0% (rodent); 1.0% (armadillo); and 1.0% (cow).ConclusionsNew scenarios of T. cruzi transmission caused by secondary and sylvatic vectors are considered. The findings of sylvatic DTUs from bugs collected in domestic and peridomestic ecotopes confirms the emerging transmission scenarios in Colombia.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1907-5) contains supplementary material, which is available to authorized users.

Colombia tiene un registro de 11 casos de Chagas agudo y 80 casos por contaminación oral con Trypanosoma cruzi. Este trabajo analiza los hallazgos entomológicos y parasitológicos del brote de Aguachica, Cesar, en 2010. Un grupo interdisciplinario de profesionales de la salud y de universidades regionales realizó las pruebas de laboratorio a los pacientes y el estudio del foco de transmisión. Se detectaron 11 casos agudos de enfermedad de Chagas en una sola familia con vivienda sin triatominos domiciliados y, Rhodnius pallescens, Pantrongylus geniculatus, Eratyrus cuspidatus y dos Didelphis marsupialis infectados con T. cruzi en palmas de Attalea butyracea y Elaeis oleifera del área urbana de Aguachica. Se analiza la participación del R. pallescens y el rol de las palmas en el ciclo silvestre de T. cruzi y para la transmisión oral de la enfermedad de Chagas. Incursiones esporádicas de R. pallescens, P. geniculatus y E. cuspidatus silvestres desde palmas cercanas al domicilio humano pueden provocar brotes cada vez más frecuentes de Chagas oral.

RESULTS:Rhodnius prolixus showed a density index of 154.7%, for Triatoma dimidiata was 102.45%, T. maculata 109.25% and Panstrogylus geniculatus 0.3%. The mean infestation index was 40.54%, and mean Trypanosoma infection index was 9.4%. Of fi ve hemocultures positive for T. cruzi, three were enzimatically identifi ed as T. cruzi group I. Biopsies revealed few pathologic characteristics of infective process with these strains isolated from domiciliary triatomine bugs. CONCLUSIONS:The high triatomine infestation indices in households and the T. cruzi infection index are evidence of active transmission of Chagas disease. The situation merits a vector control program and serological survey of the population at risk. The genetic characterization of T. cruzi strains as group I agrees with other fi ndings on strains in this region of Colombia.

Trypanosoma cruzi, the causal agent of Chagas disease, is mainly transmitted by insects of the Triatominae subfamily. In Colombia, there are 26 triatomine species, and 16 of them are naturally infected with the parasite. The parasite loads of naturally infected vectors can be significant in targeting specific species that can affect the epidemiology of the disease. Studying their ecology and behavior is vital to understand their role in T. cruzi transmission dynamics. We evaluated the parasite loads of 182 field-collected triatomines corresponding to 10 species in 13 departments across Colombia. We standardized a methodology to quantify T. cruzi DNA in these insects. We obtained a LOD (limit of detection) of 3.05 p-eq/mL. The 82% of triatomines we evaluated were positive for T. cruzi infection, with loads ranging from hundreds to millions of equivalent parasites per milliliter. Panstrongylus geniculatus, Rhodnius prolixus, and Triatoma dimidiata were the species with the highest loads of T. cruzi; however, other species whose role as vectors is still unknown were also found with high loads of parasites. Our results suggest the relevance of secondary species for T. cruzi transmission in Colombia. We hope our data can help improve entomological surveillance and vector control programs in the country and the region.

Durante el lavado de agregados pétreos para la ejecución de ensayos en el laboratorio se consumen grandes cantidades de agua. En el presente estudio se estimó, el volumen de agua que se utiliza cuando se realiza el diseño de una mezcla asfáltica. Adicionalmente se evaluó, el efecto de lavar el agregado en diversas cantidades másicas y con dos niveles de velocidad de salida de agua del grifo. Se realizó un análisis de varianza (ANOVA) para verificar si los resultados obtenidos son significativos o estáticamente iguales. Como conclusión general se reporta, que el consumo de agua disminuye significativamente cuando se lavan mayores cantidades de material al mismo tiempo y se emplea para rociar o humedecer las partículas, menores caudales.Palabras clave:  agua, consumo de agua en el laboratorio, lavado de agregados pétreos, medio ambiente.AbstractLarge quantities of water are consumed during the washing of granular aggregates in laboratory tests. In this study, the volume of water used when is designed a hot mix asphalt - HMA was estimated. Besides, the effect of washing the aggregate in different quantities of mass and with two levels of water speed flow was evaluated. An analysis of variance (ANOVA) was performed to verify if the results obtained are significant or statically equal. As a general conclusion, it is reported that water consumption decreases significantly when larger amounts of material are washed at the same time and used to wash the particles, lower flow rates.Keywords: water, water consumption in the laboratory, washing of unbound granular aggregates, environment.ResumoDurante a lavagem de agregados para a execução de testes no laboratório, grandes quantidades de água são consumidas. No presente estudo, o volume de água utilizado no projeto de uma mistura asfáltica quente foi estimado. Adicionalmente, o efeito da lavagem do agregado em várias quantidades de massa e com dois níveis de velocidade de saída da água da torneira foi avaliado. Uma análise de variância (ANOVA) foi realizada para verificar se os resultados obtidos são significativos ou estaticamente iguais. Como conclusão geral, é relatado que o consumo de água diminui significativamente quando quantidades maiores de material são lavadas ao mesmo tempo e são usadas para umedecer as partículas, taxas de fluxo menores.Palavras-chave: água, consumo de água no laboratório, lavagem de agregados, meio ambiente