Learedius learedi Price 1934 (Digenea, Spirorchiidae) in Chelonia mydasLinnaeus 1758 (Testudines, Chelonidae) in Brazil: case report [Learedius learedi Price 1934 (Digenea, Spirorchiidae) ABSTRACTThis study reports the occurrence of Learedius learedi Price 1934 (Digenea, Spirorchiidae) in Chelonia mydas Linnaeus 1758 (Testudines, Chelonidae) in Brazil. Eleven animals were included in this study, 54.6 % of them were parasitized. Two hundred and fifty five parasite specimens were recovered from heart, liver, spleen, lungs, kidneys, mesenterium, and body wash. Results contribute to the knowledge about the helminthofauna of marine chelonian and their geographical distribution. This is the first report of L. learedi in the Southwestern Atlantic.

The occurrence of Amphiorchis caborojoensis Fischthal & Acholonu 1976 and Carettacola stunkardi Martin & Bamberger 1952 in a young specimen of Hawksbill sea turtle Eretmochelys imbricata Linnaeus 1758 in Brazil was reported. Five A. caborojoensis trematodes were found in the small intestine (n=2) and liver (n=3), and two adult C. stunkardi specimens were collected from body wash. This is the first report of parasites of E. imbricata in Brazilian waters and Southwestern Atlantic Ocean and the second report of members of the Spirorchiidae family in that region. In addition, E. imbricata is a new host recorded for C. stunkardi.

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The helminth fauna associated with Leptodactylus latrans, a large frog living in a disturbed environment of Atlantic rainforest in south-eastern Brazil, was evaluated. We found eight helminth taxa, including five nematode species, Falcaustra mascula, Oswaldocruzia subauricularis, Physaloptera sp., Rhabdias sp. and an unidentified cosmocercid, two trematodes, Gorgoderina parvicava and Haematoloechus fuelleborni, and one larval cestode. The overall prevalence of infection was 63.2% with a mean intensity of 11.3 ± 3.8. The cosmocercid nematode and O. subauricularis showed the highest prevalences, although the trematode G. parvicava was the most abundant and dominant parasite species. Host size positively influenced both the intensity of infection and parasite species richness. Our data suggest that the juvenile individuals of L. latrans are more susceptible to parasitic infection than the adults. The comparison of the similarity of this community component with that found in other studies in South America shows that, as well as the characteristics of the host, the sampling area also influences the parasitic fauna. Therefore, the results of this study agree that the helminth communities of frogs have relatively low species richness and dominance of generalist species.

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The development of cage fish farms has been associated with an increase in parasitic diseases. Organic matter resulting from feed waste and faeces attracts animals such as birds and invertebrates that can act as hosts for parasites. The aim of this study was to evaluate the influence of cage farming on Austrodiplostomum compactum metacercariae infections of Plagioscion squamosissimus collected close to a cage farm in the Chavantes reservoir (Paranapanema River). Thirty-seven fish were collected in an area close to cages (CF), and 28 in an area not influenced by cages (CT). All specimens were weighed, measured and the eyes removed for morphological analyses of metacercariae. The prevalence, mean intensity of infection, mean abundance and condition factor were calculated. The prevalence (CF = 86.4%, CT = 57.1%), mean infection intensity (CF = 20.31 ± 1.13, CT = 4.29 ± 7.14) and mean abundance (CF = 17.70 ± 6.27, CT = 2.35 ± 0.77) were higher in the CF (P< 0.05) group. There were no significant correlations (P> 0.05) between the mean abundance and standard length or the total weight and condition factor in either group (P> 0.05). Fish farms may interfere with the life cycle of A. compactum, leading to more infections with P. squamosissimus. This could be due to an increase in the number of host animals that are attracted by the availability of food resources derived from fish farms.

The goal of this study was to determine the prevalence of Hepatozoon spp. infection in recently captured snakes from Botucatu, São Paulo State, Brazil. Blood was collected from all snakes by ventral tail venipuncture. Blood smears were air dried, fixed with methanol, and stained with 10% Giemsa solution. The slides were microscopically examined for detection of hemoparasites by light microscopy at 250x magnification. A total of 238 snakes from 23 species were examined, of which 135 (56.7%) were venomous and 103 (43.3%) non-venomous snakes. The more numerous venomous species sampled were Crotalus durissus terrificus (n=108) and Bothrops jararaca (n=17) and non-venomous snakes were Oxyrhopus guibei (n=35), Boa constrictor amarali (n=18), and Waglerophis merremi (n=13). Hepatozoon spp. infection was detected in 39 (16.4%) snakes. The prevalence in venomous and non-venomous snakes was 20.0% and 11.7%, respectively. The highest prevalences observed were 38.9% for Boa constrictor amarali, 35.3% for Bothrops jararaca, and 19.4% for Crotalus durissus terrificus.

Sympatric hosts are exposed to similar ecological conditions, particularly if they are closely related phylogenetically and share some physiological and behavioral traits. We studied the sympatric frogs Leptodactylus chaquensis Cei, 1950 and Leptodactylus podicipinus (Cope, 1862) to investigate the extent to which the helminth parasite communities were influenced by host species’ characteristics or habitat location. We described and compared the helminth communities of 50 L. chaquensis and 40 L. podicipinus collected concurrently from two different study sites in Brazil’s Pantanal floodplain. Similarities in the prevalence and mean abundance of helminths were higher among allopatric populations of the same species than among sympatric populations of different species. The effects of host species, size, and habitat on helminth composition were significant. The amount of variance in the helminth community composition explained by host species and size was greater than that explained by host habitat. These results indicate that the main factors determining similarities in parasite species in this study system are the coevolutionary and biological constraints of the host species, which either limit or allow infection of the parasite species despite the host habitat.