Parasitism of Dirofilaria incrassata Molin, 1858 in coatis (Nasua nasua).

Populations of the coati, Nasua nasua, like the populations of other wild animals, are regulated by several biotic or abiotic factors. For example, parasites act as a biotic factor affecting the dynamics and density of coati populations. The parasitic nematodes of coatis include Dirofilaria species, such as Dirofilaria immitis, Dirofilaria repens, and Dirofilaria incrassata. Considering that there are few records on parasitism by D. incrassata, including information on the life cycle or location in the host body, this study aimed to investigate the infection of N. nasua by D. incrassata in midwestern Brazil. Thus, two coatis (males and adults) from the Cerrado of Goiás, which died (cause unknown) at the Wild Animal Screening Center/IBAMA in the municipality of Goiânia, Goiás, Midwestern of Brazil, were dissected and all helminths found were collected, identified following specific keys and quantified. A total of 85 specimens of D. incrassata were collected, with a mean parasitic intensity of 42.5 and a parasitic amplitude ranging from 40 to 45, measuring 41-93 mm in length and 0.23-0.45 mm in width. All helminths were adults and were distributed in the superficial and deep fascia (at different levels) from the neck to the hind limb. Most helminths were tangled, with some encased in a connective tissue film. Most reported human heartworm cases refer to subcutaneous or ocular heartworm infection, mainly caused by D. repens, although other species of heartworm may be associated. D. incrassata was not reported as zoonotic agent, diferently of other Dirofilaria species associated with wild animals and with zoonotic potential in the Americas. This study reiterates N. nasua as the definitive host for D. incrassata and the subcutaneous tissue as the site of choice for this helminth in the adult form. In addition, it reports new body regions where the parasite occurs. This study is the first to document the occurrence of D. incrassata infestation in the State of Goiás, Brazil.