Gleasonian structure in the helminth metacommunity of the opossum Didelphis albiventris in two extremes of the Atlantic Forest

First record of Brachylaima asakawai (Trematoda: Brachylaimidae) in a carnivore host, the red fox (Vulpes vulpes schrencki)

Accumulating information on the relationship between hosts and parasites is important to understand their life cycle. Nine Brachylaima spp. species exist in Japan, but their life cycles are not fully understood, partly because of their low prevalence in their definitive hosts. In this study, 23 trematodes, thought to belong to the genus Brachylyma were found in the small intestine of the red fox (Vulpes vulpes schrencki) in Hokkaido, Japan. We analyzed these trematodes using morphological and molecular methods. Morphological analysis showed that the trematodes had the same features as Brachylaima asakawai. We extracted DNA from the trematodes and amplified the nuclear 28S ribosomal RNA (28S rDNA) and mitochondrial cytochrome c oxidase subunit 1 (cox1) genes. The 28S rDNA and cox1 fragments were 100 % and 99.7 % identical to the B. asakawai, respectively. Previously, B. asakawai was detected only in rodents in Hokkaido; however, this study demonstrated that it is also a fox parasite. This is the second report of a definitive natural host for B. asakawai and the first record of the red fox being found as a new definitive host for B. asakawai. To fully understand the host preference and range of B. asakawai, it is essential to continuously survey various animals to understand the life cycle of B. asakawai completely.

Endoparasites of marsupials in fragments of the Atlantic rainforest, western Paraná State, Brazil

Knowledge of taxonomy and biodiversity of parasites is fundamental to better understand ecosystem dynamics. The objective of this study was to describe the helminth fauna of two species of marsupials in five fragments of the Atlantic rainforest in the western region of Paraná State, Brazil. In a total of 4050 trap-nights, the animals were captured using Sherman, Tomahawk, and Pitfall traps, euthanized, necropsied, and their organs inspected for helminths. After identification of the parasites, descriptors of infection, such as prevalence, mean abundance, mean intensity, and range of intensity, were calculated. Collectively, six helminth species were observed in 18 animals. The following five species were observed in Marmosa paraguayana: Viannaia hamata (58.8%), Gracilioxyuris agilisis (52.9%), Travassostrongylus sextus (17.6%), Oncicola luehei (5.9%), and Pritchardia boliviensis (5.9%). Whereas the following two species were observed in Monodelphis dimidiata: Trichohelix tuberculata (100%) and Travassostrongylus sextus (100%). This study represents a new locality record for all helminths described herein, and a new host for four helminth species. This is the first report on the helminth fauna of Monodelphis dimidiata, expanding knowledge about marsupials in the Brazilian Atlantic Forest.

Helminth community structure of Didelphis marsupialis (Didelphimorphia, Didelphidae) in a transition area between the Brazilian Amazon and the Cerrado

Although the common opossum, Didelphis marsupialis (Didelphimorphia: Didelphidae) is a species widely distributed in South America, knowledge about their helminth parasites and helminth community structure is scarce. The aims of this study were to describe the species composition and analyze the structure of the helminth community of the common opossum in an area of the Amazonian Arc in northern Mato Grosso. The helminths were recovered, counted, and identified in 32 individuals. Overall, 10,198 specimens were categorized into 9 helminths taxa (seven nematodes, one cestode, and one acanthocephalan). The most abundant species were Aspidodera raillieti, Viannaia hamata, and Travassostrongylus orloffi. No statistically significant differences in helminth abundance and prevalence were observed between host sexes. However, young hosts had higher abundance and prevalence of Didelphonema longispiculata, whereas Oligacanthorhynchus microcephalus had higher abundance and prevalence in adult hosts. This was the first study to analyze the helminth fauna and helminth community structure of D. marsupialis in the Amazonian Arc. This is the first report of the presence of A. raillieti, D. longispiculata, T. orloffi, T. minuta, V. hamata, and O. microcephalus in the state of Mato Grosso, Brazil.