Distribution patterns of Procamallanus (Spirocamallanus) inopinatus (Nematoda: Camallanidae) and its interactions with freshwater fish in Brazil

Abstract

This study used information about Procamallanus (Spirocamallanus) inopinatus Travassos, Artigas & Pereira, 1928 that had been published over a period of more than 90 years to investigate the infection and distribution patterns of this nematode in teleost freshwater fish in Brazil. This study was carried out using 181 samples from 82 fish species in 19 families within the five orders, with predominance of Characiformes species (71.6%). We organized a matrix-based parasite-host system in which the fish species were classified in different trophic levels and parasitic infection parameters according data available on host fish species with different life histories and geographic distributions across Brazilian hydrographic basins. Procamallanus (S.) inopinatus showed prevalence ranging from low to moderate, low abundance, low intensity, typically aggregated dispersion, and preferential infection of the hosts' gastrointestinal tract. There was difference in prevalence between detritivorous, omnivorous, carnivorous and piscivorous hosts, but no difference in intensity and abundance was found due to similarity in the communities of this endoparasite among the host fish species. The geographic distribution of this parasite encompasses the river of the Amazon, Paraná, São Francisco, North Atlantic, South Atlantic and Eastern basins. Lastly, suggestions regarding the life cycle of P. (S.) inopinatus, with its potential intermediate hosts, were discussed.

Community and infracommunities of metazoan parasites in Hemiodus unimaculatus (Hemiodontidae) from Jari River basin, a tributary of Amazon River (Brazil)

“…In fish from Brazil, P. (S.) inopinatus are found in the adult stage, with prevalence ranging from low to moderate, low intensity and low abundance (Neves et al, 2020), similar to that shown in the present study with H. unimaculatus. This level of parasitism can be attributed to the fact that this nematode has a complex life cycle, with transmission through prey-predator interactions (Thatcher, 2006;Neves et al, 2020).…”

“…In H. unimaculatus from the Jari River, the parasites showed an aggregated dispersion, a typical pattern in different parasitic species in fish (Rohde et al, 1995;Guidelli et al, 2003;Tavares-Dias et al, 2013;Gonçalves et al, 2018). However, infection by P. (S.) inopinatus showed random dispersion, a pattern that is reported for nematode species of fish parasites due to its pathogenicity (Gonçalves et al, 2018;Neves et al, 2020). Gaines et al (2012) reported that P. (S.) inopinatus is pathogenic, causing severe histopathological changes in the intestine of Arapaima gigas (Schinz, 1822).…”

Parasitism of Arapaima gigas (Schinz, 1822) in fish farms of the state of Amazonas, Brazil

“…was also recorded in only one fish from one fish farm, with low parasitic indices. This species of parasite has also been reported in approximately 82 species of freshwater fish from Brazil, including A. gigas, with low values of mean intensity and abundance, in addition to prevalence ranging from low to moderate, and this low level of parasitism may be, in part, due to its complex heteroxenic life cycle (Neves et al, 2020). Similar to what is observed for Hysterothylacium sp., a strong and positive relationship of this parasite with the weight and total length of A. gigas was found.…”

Diversity and community ecology of metazoan parasites in Pimelodus ornatus (Siluriformes: Pimelodidae) from the Amazonas River in Brazil

“…for P. ornatus. Procamallanus (S.) inopinatus, a nematode with wide geographic distribution and is found in different species of fish in Brazil (Neves et al 2020b), was recorded here for the first time in P. ornatus. This endoparasite was the dominant species in P. ornatus and had a higher level of infection when compared to Contracaecum sp.…”