Dual approach of Trypanosoma cruzi and/or Plasmodium spp. infections for Chagas disease diagnosis and the presence of triatomine vector in the Brazilian Amazon

Abstract

As part of the surveillance strategy for early diagnosis of acute Chagas disease (ACD), it was evaluated the incidence of infections by Trypanosoma cruzi and/or Plasmodium spp. in this cross sectional study in inhabitants of different endemic levels for both infections and it was also described for the first time the human riverian population exposured to the contact with triatomine wild insect vectors. Two surveys were carried out, the first one with parasitological approach and the second one was a serological survey, directed to different endemic levels areas for malaria and Chagas disease respectively. Thick blood films (TBF) and immunoenzymatic (ELISA) and indirect immunofluorescence assays were used for IgG antibodies anti T. cruzi surveys. In Anajás City, Pará State, Brazil, 1.017 people were examined with a history of current or recent fever and also asymptomatics. Among the total, 90.3% (918/1.017) presented negative parasitological results and 9.7% (99/1.017) were positive for plasmodia, with P vivax (75/1.017), P falciparum (21/1.017) and mixed-species malaria infections (2/1.017). Among the positive results, 45.5% (45/99) were children under 12 years of age. It was identified one case of infection by T. cruzi in TBF and following this diagnosis it was registered one family outbreak of ACD. In Abaetetuba City, Pará State, 119 asymptomatic individuals were evaluated with a previous history of contact with wild triatomines. All their results were negative; however, for the first time, it was registered a high human exposition to triatomines. The ACD case diagnosed by TBF demonstrated the success of dual diagnosis strategy to febrile illness individuals in Brazilian Amazon region. Rates of malaria infection, especially in children, reinforced their importance as a potential gametocyte source for Plasmodium spp. transmission to malaria vectors. The interrelation between transmitters of Chagas disease and riverian population deserves further entomological studies.