One Health and Wildlife: The Role of Coatis (Nasua nasua) in the Circulation of Zoonotic Diseases

The coati (Nasua nasua Linnaeus, 1766) is a mammal belonging to the family Procyonidae, widely distributed throughout South America, occurring in biomes such as the Atlantic Forest, Cerrado, and Caatinga (REIS et al., 2011; EMMONS; FEER, 1997). These animals are diurnal, omnivorous, and highly adaptable, inhabiting both natural ecosystems and anthropized environments (BEISIEGEL, 2001). Their social behavior, characterized by females and juveniles living in groups, combined with their generalist diet, promotes frequent contact with human refuse, domestic animals, and potentially contaminated environments (REIS et al., 2011). Habitat fragmentation has increased the exposure of this species to a variety of infectious agents, including parasites and microorganisms with high zoonotic potential. Consequently, coatis serve as important reservoirs or maintenance hosts for parasites, playing a significant role in the epidemiology of zoonotic diseases involving wildlife, domestic animals, and humans (HERRERA et al., 2007; ANDRÉ et al., 2019a).

        Vector-borne pathogens represent some of the most important zoonotic threats circulating among coati populations in Brazil, exhibiting high prevalence and remarkable etiological diversity (ANDRÉ et al., 2023). In Iguaçu National Park, hemotropic Mycoplasma sp. was the most frequently detected pathogen, infecting 85.7% (42/49) of the sampled animals, followed by Bartonella machadoae, detected in 24.5% (12/49), expanding the known host range of this bacterium beyond rodents (ANDRÉ et al., 2023). Anaplasma sp., genetically related to "Candidatus Anaplasma brasiliensis", was identified in 14.3% (7/49) of the coatis, whereas Hepatozoon procyonis occurred in 6% (3/49) of the evaluated individuals (ANDRÉ et al., 2019). Coinfections were common, with 18.3% of the animals simultaneously infected by Mycoplasma and Bartonella, 12.2% by Mycoplasma and Anaplasma, and 4% presenting triple infections involving vector-borne bacteria (ANDRÉ et al., 2023).

           Filarial nematodes also exhibited remarkably high prevalence. In Iguaçu National Park, the Knott test revealed filarial infection in 81.6% of the sampled coatis, identifying seven morphotypes, including Dirofilaria immitis, Dirofilaria repens, Acanthocheilonema reconditum, Brugia sp., and Mansonella sp., with D. immitis detected in 1.33% of the animals (ANDRÉ et al., 2019). In urban areas of the Brazilian Midwest, Mansonella sp. infection was even more pronounced, with microfilariae observed in 30% of blood smears and in up to 80% of the leukocytes analyzed (DA SILVA et al., 2023).

                Studies also emphasize the importance of coatis in maintaining Trypanosoma cruzi, particularly in the Pantanal. Serological tests and hemocultures performed between 2000–2001 and 2005–2007 demonstrated high prevalence and intense parasite transmission (HERRERA et al., 2007; HERRERA et al., 2008). The recovery of different genotypes from the same individual over a period of up to eight months suggests both reinfections and the simultaneous persistence of multiple parasite lineages, reinforcing the epidemiological role of coatis in the circulation of strains associated with human Chagas disease (HERRERA et al., 2008). Furthermore, the detection of Trypanosoma evansi in coatis from Mangabeiras Municipal Park, an area considered non-endemic, suggests a recent introduction of the parasite and highlights the species as a potential reservoir or epidemiological sentinel (ROCHA et al., 2019).

        In addition to protozoa and bacteria, viruses and emerging helminths have also been reported in coati populations. The SARS-CoV-2 Zeta variant (P.2) was detected by RT-qPCR in 5% (2/40) of the animals captured between February and August 2021, whereas serological testing revealed a 50% seropositivity rate, indicating widespread viral exposure (ANDRÉ et al., 2022). Genetic sequencing confirmed a high degree of similarity with local human strains, supporting the hypothesis of human-to-animal transmission (ANDRÉ et al., 2022). Finally, the description of Angiostrongylus minasensis n. sp. in urban coatis from Belo Horizonte, confirmed through morphological and phylogenetic analyses of the cox1 gene, represents an important finding, considering that species of the genus Angiostrongylus are associated with eosinophilic meningitis and neuroangiostrongyliasis in humans (SIMÕES et al., 2020).

          The frequent interactions among coatis, humans, and domestic animals in urbanized and tourist areas increase the potential for spillover and spillback events. Spillover occurs when infectious agents circulating in wildlife are transmitted to humans or domestic animals, whereas spillback refers to the reverse process, in which pathogens introduced by humans or domestic animals become established within wildlife populations. In Iguaçu National Park, where coatis frequently interact with visitors and anthropogenic food waste, these processes become particularly relevant. The detection of zoonotic agents such as filarial nematodes, Trypanosoma cruzi, and, more recently, SARS-CoV-2 demonstrates that the wildlife–domestic animal–human interface may facilitate the bidirectional circulation of pathogens (ANDRÉ et al., 2019a; ANDRÉ et al., 2022; DESTOUMIEUX-GARZÓN et al., 2018). Although the individual risk of infection for visitors is considered low in the absence of direct animal contact, frequent close interactions, inappropriate wildlife feeding, and inadequate waste disposal may increase opportunities for exposure to infectious agents and promote behavioral changes that bring coatis even closer to anthropogenic environments.

         Despite the public health importance associated with coatis, their presence in urban environments should not be interpreted as an isolated wildlife issue, but rather as a direct consequence of environmental changes caused by human activities (DESTOUMIEUX-GARZÓN et al., 2018). From a One Health perspective, wildlife conservation and the reduction of zoonotic risks should be understood as complementary and interdependent objectives (DESTOUMIEUX-GARZÓN et al., 2018).

      Finally, the preservation and restoration of forest fragments, combined with the establishment of ecological corridors and environmental education programs, constitute essential measures for coati conservation and for reducing health risks at the human–wildlife interface. In tourist areas such as Iguaçu National Park, visitors should avoid feeding or handling wildlife, maintain a safe distance, and dispose of waste appropriately. Likewise, owners of dogs and cats living in areas where coatis occur should keep vaccination, deworming, and ectoparasite control up to date, restrict domestic animals' access to forested areas, and prevent direct interactions with wildlife. Continuous wildlife health surveillance, together with the integration of environmental agencies, public health services, and local communities, represents an essential strategy to minimize spillover and spillback events while promoting actions aligned with the principles of One Health (DESTOUMIEUX-GARZÓN et al., 2018)

Figure 1. Group of coatis. Image source: Onçafari.

^{Author: Maria Eduarda Panisson Balzan - Southern Regional Representative}

^{Review: Iago Junqueira – Partner of GEAS Brazil through The Wild Place}

 ^{Wildlife Panel – July/2026}

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