The phylum Nematoda is considered one of the most diverse groups in South America, as it is found in all habitats and is dynamic regarding the ecological characteristics of environments, this group becomes important for monitoring the state of ecosystems, thus making it of great importance. Its identification and occurrences in western Amazonia. Thus, the present study aims to present a list of fish nematodes in western Amazonia, as well as to describe their specific hosts. The study was carried out in the Alto Juruá region of the Western Amazon around the municipalities of Cruzeiro do Sul – Acre and Guajará – AM, Brazil. A total of 10,716 fish were collected, belonging to eight orders, 32 families and 216 species, with only 164 species showing nematodes. The species with the highest number of hosts were Procamallanus (S.) inopinatus Travassos et al., (1928), (67), Contracaecum sp....

Nematodes are parasites widely distributed in aquatic environments and are among the helminths of greatest relevance to global public health. Among the species that affect fish, some exhibit zoonotic potential, that is, they are capable of infecting humans. In parasitized individuals, infections may manifest in different clinical forms, including larval penetration of the gastric or intestinal mucosa, leading to inflammatory processes and, in some cases, gastrointestinal complications. In this context, the present study aimed to conduct a systematic review on the occurrence and distribution of zoonotic nematodes in fish in Brazil, with emphasis on identifying the species involved and their main hosts. Articles published between 2000 and 2025, written in Portuguese and English, and restricted to the Brazilian territory were included. A total of 63 articles were selected, allowing a compre...

Larvae of the genus Contracaecum can be found in several species of fish. This study aims to analyze the prevalence, incidence and average abundance of Contracaecum sp. in fish, and to relate host species richness to parasite abundance. A total of 2888 specimens of host fish were collected, and only 217 specimens showed Contracaecum sp. infections. A total of 64 species of fish were collected, in which the greatest richness of hosts was evidenced during the dry season. During the dry season, the highest prevalence values ​​of Contracaecum sp. were found in Erythrinus erythrinus (P=43.18%) and Acestrorhynchus sp. (P=17.39%).  The values ​​of high abundance (AM= 0.73) and average intensity (IM= 9.77) were evidenced in Sorubim lima. During this period, the relationship between host richness and occurrence of Contracaecum sp. was also significant. In conclusion, the study showed the...

The family Raphidascarididae is composed of nematodes that carry out their life cycle in environments using diverse intermediate or paratenic hosts including invertebrates, fish, waterfowl, and mammals. The genera of this family include Raphidascaris Railliet & Henry, 1915, Ichthyascaris Wu, 1949 and Sprentascaris Petter & Cassone, 1984; all can act as fish parasites. The objective of this work was to analyze host fish of the family Loricariidae including two species of zoonoticnematodes. The study was carried out in the municipality of Cruzeiro do Sul, Acre, Brazil. A total of 42 Sprentascaris mahnerti Petter & Cassone, 1984 was collected from three hosts of the family Loricariidae, 27 from Limatulichthys griseus Eigenmann, 1909, 10 from Spatuloricaria sp. Schultz, 1944 and 5 in Hypoptopoma steindachneri Boulenger, 1895. For Raphidascaris sp. Railliet & Henry, 1915 a tot...