Temperature influences the excretion time and parasitic load ofTrypanosoma cruziin theTriatoma infestansvector

Abstract

AbstractTrypanosoma cruziis a protozoan parasite transmitted by triatomine insect vectors, which expel their infectious dejections when they feed, causing Chagas disease in humans. The transmission and incidence of this vector-borne disease depend on the vital traits of its vectors, includingTriatoma infestans, the main vector in Southern South America. Being an ectothermic species, its metabolism and its vital traits respond to temperature fluctuations. Here, we evaluated if changes in the average and variability of temperature expected with climate change modify: (i) the extrinsic incubation period (EIP) ofT. cruziwithin the vectorT. infestans, (ii) its parasitic load, and (iii) the probability that its dejections wereT. cruzi-positive. We acclimated triatomines infected with Dm28cT. cruzistrain to two constant and two variable temperature treatments and measuredT. cruziin their dejections by qPCR over a 42-day period. We observed that individuals in warm-temperature treatments showed lower EIP and higher parasitic load than cold-temperature treatments. Also, temperature variability can increase the parasitic load peak in cold-temperature treatments. Consequently, in a climate change scenario, there might be an increase in the vector capacity ofT. infestansand probably a change in the risk of vectorial transmission ofT. cruzi.