Co-Infection and Wild Animal Health: Effects of Trypanosomatids and Gastrointestinal Parasites on Coatis of the Brazilian Pantanal.

Wild animals are infected by diverse parasites, but how they influence host health is poorly understood. We examined the relationship of trypanosomatids and gastrointestinal parasites with health of wild brown-nosed coatis (Nasua nasua) from the Brazilian Pantanal. We used coati body condition and hematological parameters as response variables in linear models that were compared using an information theoretic approach. Predictors were high/low parasitemias by Trypanosoma cruzi and T. evansi, and indices representing the abundance of distinct groups of gastrointestinal parasites. We also analyzed how host health changed with host sex and reproductive seasonality. Hemoparasites was best related to coati body condition and hematological indices, whereas abundance of gastrointestinal parasites was relatively less associated with coati health. Additionally, some associations were best predicted by models that incorporated reproductive seasonality and host sex. Overall, we observed a lower health condition during the breeding season, when coatis are under reproductive stress and may be less able to handle infection. In addition, females seem to handle infection better than males. Body condition was lower in coatis with high parasitemias of T. evansi, especially during the reproductive season. Total red blood cell counts, packed cell volume, platelets and eosinophils were also lower in animals with high T. evansi parasitemias. Total white blood cell counts and mature neutrophils were lower in animals with high parasitemias for both Trypanosoma species, with neutrophils decreasing mainly during the reproductive season. Overall, decreases in hematological parameters of females with T. evansi high parasitemias were less evident. For T. cruzi, monocytes decreased in individuals with high parasitemias. High abundances of microfilariae in the bloodstream, and cestode eggs and coccidian oocysts in feces were also associated with coati blood parameters. This study shows the potential value of examining hematological parameters as an approach to better understand the ecological relevance of parasite-host interactions.

Modulating variables of Trypanosoma cruzi and Trypanosoma evansi transmission in free-ranging Coati (Nasua nasua) from the Brazilian Pantanal region.

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.