Modulating Variables ofTrypanosoma cruziandTrypanosoma evansiTransmission in Free-Ranging Coati (Nasua nasua) from the Brazilian Pantanal Region

Abstract

This is a long-term follow-up of infection by Trypanosoma cruzi (TC) and Trypanosoma evansi (TE) in the free-ranging coatis (Procyonidae: Nasua nasua) from Pantanal region (Mato Grosso do Sul, Brazil). We evaluated TC and TE infection by immunofluorescence assay, hemoculture (HC), and microhematocrit centrifuge techniques (MHCT). We also examined coatis health by quantifying hematological parameters including packed cell volume (PCV), white blood cell (WBC) count, and differential leukocyte count. TC isolates thought HC were typed by miniexon gene. Mixed infections by both parasites and the two main lineages of TC (76% TCI, 3% TCII, and 14% TCI/TCII) were observed. Trypanosoma rangeli was also isolated (7%). Overall, seroprevalence of TC and TE infection were 53.5% and 42.0%, respectively. Positive HC (indicating high TC parasitemia) occurred in 34% of seropositive coatis for TC, and positive MHCT (high TE parasitemia) were observed in 36.4% of seropositive coatis for TE. We detected higher prevalence of positive HC in females (72%) than males (43%), and also during the dry season, indicating a seasonal potential of this host species on TC transmission. These features did not occur for TE infection. However, prevalence of TE based on serology and MHCT was higher among adults than subadults. Coatis with positive HC or MHCT displayed a slight decrease in their WBC. In contrast to the animals with positive HC, coatis with positive MHCT displayed a decrease on their PCV. Moreover, concurrent high TC and TE parasitemia caused a larger decrease of PCV values. This study corroborates the importance of coatis in the maintenance of TC and TE transmission cycles in the southern Pantanal and shows a seasonal character of TC transmissibility to its vector by the coati population from the study area.

Trypanosoma cruzi Infection in Neotropical Wild Carnivores (Mammalia: Carnivora): At the Top of the T. cruzi Transmission Chain

“…Notwithstanding, based on the positive hemoculture only the ring-tailed coatis and the crab-eating raccoons demonstrated a potential to infect vectors. This is in accordance with previous studies that report the role played by the ring-tailed coati as the main reservoir of T. cruzi in the Pantanal due to its high prevalence of infection, long-lasting parasitemia and infection with the main T. cruzi lineages [14], [44], [45]. Moreover, the coati has numerous paths for contact with T. cruzi , as it occupies both arboreal and terrestrial strata in several habitat types and can prey on infected insects and mammals [46].…”

“…As already observed [45], the ring-tailed coati was the only carnivore species examined in this study to display gender differences in the infection rate. Coatis have an unique social system among carnivore species; males and females have marked differences in their ecology, as females live in groups while most adult males are solitary (except during the breeding season) [51].…”

“…Previously, single TcI and TcII/TcV/TcVI infections were reported to occur in similar ratios, whereas TcIII/TcIV (formerly Z3) and Trypanosoma rangeli (TR) occurred in minor proportion [44]. Herein, TcI has prevailed over TcII/TcV/TcVI whereas TcIII/TcIV, which was not reported in the past few years [45], was isolated again from the coati population. We also observed a gradual increase in the prevalence of T. rangeli (3%–[44]; 7%–[45]; 20% this study).…”

“…Herein, TcI has prevailed over TcII/TcV/TcVI whereas TcIII/TcIV, which was not reported in the past few years [45], was isolated again from the coati population. We also observed a gradual increase in the prevalence of T. rangeli (3%–[44]; 7%–[45]; 20% this study). It is well-known that the striking variation of the flooding intensity in the Pantanal, as well as other environmental changes, has a strong effect on the local community structure, modulating vectors, hosts and consequently their parasites density, distribution and interrelationships [27], [47].…”

“…Another coati’s ecological characteristic that facilitates infection by T. cruzi is its behavior of construction of arboreal nests for resting and reproduction, as we have found several of these nests infested with triatomine bugs in our recent field observations (J. Saab, unpublished data ). Along with its potential to infect vectors and the capacity to maintain multiples lineages of the parasite [44], [45], this species may be considered a network hub, a common connection point joining transmission cycles maintained within terrestrial and arboreal mammals and vectors.…”