Complexity and multi-factoriality of Trypanosoma cruzi sylvatic cycle in coatis, Nasua nasua (Procyonidae), and triatomine bugs in the Brazilian Pantanal

Abstract

BackgroundTrypanosoma cruzi is dispersed in nature through many transmission mechanisms among a high diversity of vectors and mammalian species, representing particular behaviors and habitats. Thus, each locality has a unique set of conditions underlying the maintenance of this parasite in the wild. The aim of the present study was to evaluate the life-cycle of T. cruzi in free-ranging coatis from the central region of the Brazilian Pantanal using a multi-factorial approach.MethodsThree methodological blocks were used in the present study: (i) We evaluated T. cruzi infection using serological (ELISA) and parasitological (hemoculture) tests in free-ranging coatis captured from October 2010 to March 2012. In addition, we characterized T. cruzi isolates as DTUs (Discrete Typing Units); (ii) We evaluated Trypanosoma infection in species of Triatoma and Rhodnius inhabiting coati arboreal nests from May to September 2012 using parasitological and molecular assays; and (iii) We analyzed a set of longitudinal data (from 2005 to 2012) concerning the effects of T. cruzi infection on this coati population. Herein, we investigated whether seasonality, host sex, and host age influence T. cruzi prevalence and patterns of infection.ResultsThe 2010–2012 period presented high seroprevalence on coatis (72.0 % ELISA) and a high percentage of individuals with infectivity competence (20.5 % positive hemoculture). All isolates presented TcI band patterns, occurring in single (n = 3) and mixed infections (1 TcI/T. rangeli; 4 with undefined characterization). Both male and female individuals presented the same transmission potential, expressed as positive hemoculture, which was only detected in the summer. However, overall, the data (2005–2012) highlighted the importance of females for T. cruzi maintenance in the winter. Moreover, twenty-three (67.6 %) bugs from five coati nests (71.4 %) were infected with flagellated forms. Seventeen samples were characterized as T. cruzi (TcI and TcIII genotypes).ConclusionIn the Pantanal region, T. cruzi is transmitted in a complex, multifactorial, dynamic and non-linear transmission web. The coati nests might be inserted in this web, acting as important transmission foci at the arboreal stratum to different mammal species with arboreal or scansorial behavior.

Molecular detection of Hepatozoon spp. in domestic dogs and wild mammals in southern Pantanal, Brazil with implications in the transmission route

“…The Pantanal is the largest Neotropical floodplain and it is well known for a rich biodiversity. Two well-defined seasons are recognized: a rainy summer (October to March) and a dry winter (April to September) (Alves et al, 2016).…”

Outcomes of Trypanosoma cruzi and Trypanosoma evansi infections on health of Southern coati (Nasua nasua), crab-eating fox (Cerdocyon thous), and ocelot (Leopardus pardalis) in the Brazilian Pantanal

“…Mean corpuscular volume (MCV) was calculated based on the RBC and PCV values. The immunoglobulin concentration (IgG) was determined by titration with the indirect fluorescent antibody test (IFAT) [ 27 , 28 ] and by optical density using enzyme-linked immunosorbent assay (ELISA)[ 29 ]. Leukocyte (eosinophils, lymphocytes, monocytes, and neutrophils) counts were performed using blood smears fixed with methanol and stained with Giemsa [ 30 ].…”

“…To detect anti- T . cruzi IgG antibodies, we used IFAT (fluorescein-conjugated antibody against dogs and cats IgGs) and ELISA (fluorescein-conjugated antibody against raccoon’s IgGs), as described by Rocha et al [ 28 ] and Alves et al [ 29 ], respectively. The cut-off value for ELISA was defined as the mean optical absorbance of the negative controls +20%.…”

“…The cut-off value for ELISA was defined as the mean optical absorbance of the negative controls +20%. We added two positive and two negative control sera to each reaction plate, as described by Alves et al [ 29 ].…”

VALORES HEMATOLÓGICOS DE LOBINHOS (Cerdocyon thous) DO PANTANAL, MATO GROSSO DO SUL, BRASIL NATURALMENTE INFECTADOS E NÃO INFECTADOS POR Trypanosoma cruzi e T. evansi

“…No entanto, a falta da análise microscópica dos esfregaços sanguíneos não permitiu essa confirmação, principalmente na ausência do valor do Conteúdo de Hemoglobina Corpuscular Média (CHCM), imprescindível na correlação microscópia, para definir a morfologia eritrocitária. Principalmente nesse caso, em que a macrocitose calculada é muito superior aos valores de referências publicados (49,36,37) e poderiam caracterizar intensa regeneração eritrocitária, ainda que os menores valores eritrocitários indicassem apenas anemia discreta, segundo os valores de referência (31) .…”