Trypanosoma cruzi and Trypanosoma rangeli in Acre, Brazilian Amazonia: Coinfection and Notable Genetic Diversity in an Outbreak of Orally Acquired Acute Chagas Disease in a Forest Community, Wild Reservoirs, and Vectors

Abstract

Acute Chagas disease (ACD) caused by Trypanosoma cruzi has emerged as a major food-borne disease in Brazilian Amazonia. For the first time, we characterized an outbreak of orally acquired ACD in Acre, in the forest community of Seringal Miraflores, affecting 13 individuals who shared the pulp of açai palm berries: 11 adults and two children (one newborn), all diagnosed by thick-drop blood smears. The fluorescent fragment length barcoding method, which simultaneously identifies species/genotypes of trypanosomes in blood samples, uncovered an unprecedented genetic diversity in patients from a single outbreak of ACD: T. cruzi TcI in all patients, mostly concomitantly with the non-pathogenic Trypanosoma rangeli of genotypes TrA or TrB, and TcI, TcIV, and TrB in the child. The patients presented persistent fever, asthenia, myalgia, edema of the face and lower limbs, hepatosplenomegaly and, rarely, cardiac arrhythmia. The clinical symptoms were not correlated to gender, age, or to trypanosome species and genotypes. The inferred SSU rRNA phylogenetic analyses of trypanosomes from humans, triatomines and sylvatic hosts included the first sequences of T. cruzi and T. rangeli from humans in southwestern (Acre and Rondônia) Amazonia, and the first TcI/TcIV sequences from Rhodnius spp. from Acre. The sylvatic transmission cycles of genetically different trypanosomes in landscapes changed by deforestation for human settlements and increasing açai production is a novel scenario favoring trypanosome transmission to humans in Acre.