Prevalence of Larval-Stage Dicrocoeliidae (Digenea) Trematodes in Helix lucorum (Mollusca: Pulmonata) in Van Province.

OBJECTIVE: The aim of this study was to investigate the prevalence of larval-stage Dicrocoeliidae trematodes in Helix lucorum, a land snail found in Van Province. METHODS: Helix lucorum snails were collected in April, May, and June 2017 from Edremit and Gevas, the central districts of Van Province, especially from natural areas where ruminants predominate. The snails were anesthetized with magnesium chloride, were removed from their shells, and their digestive glands were disrupted. The disrupted parts were examined under a microscope. RESULTS: In Van Province, H. lucorum snails were found to be intermediate hosts for Dicrocoelium trematodes with a prevalence of 22%. The larval stages detected in the microscope are photographed and shown in detail. The number of infection with larval stages of the parasite was found to be highest in May. CONCLUSION: Helix lucorum the land snail, serves as an intermediate host for some developmental stages of the Dicrocoeliid trematodes, is also consumed as nutrients by humans in some countries. Based on the obtained results in this study, it can be concluded that this snail would have important effects on animal health in the Van region which has a hard climate and a border with Iran.

Can the same species of Platynosomum (Trematoda: Dicrocoeliidae) infect both mammalian and avian hosts?

The importance of platynosomiasis has increased in feline veterinary practice, but aspects related to the specificity of Platynosomum spp. in definitive hosts requires further study. Although morphological traits suggest that the same species, P. illiciens, may infect both birds and mammals, the synonymies previously proposed have not been widely accepted, likely because host specificity is assumed. In addition, the name P. fastosum has frequently been used for parasites recovered from mammals. In the present study, metacercariae (n= 100/animal) of P. illiciens recovered from lizards (Hemidactylus mabouia) in Brazil were fed to Australian parakeets (Melopsittacus undulatus) and mice. Two parasites were recovered from the liver of one M. undulatus specimen during a necropsy that was performed 105 days after infection, and all mice were found to be infected with 37 ± 12 (18-48) parasites. The morphology of the P. illiciens obtained from the parakeet was similar to that of parasites obtained from mice and those described previously from naturally infected birds and mammals. Non-specificity of P. illiciens in hosts is discussed briefly, based on the parasitological and morphological results obtained during the avian experimental platynosomiasis and the epidemiology and geographical distribution of this parasite.

Statistical experimental design to assess the influence of enzymes of nematophagous fungi versus helminths.

The present work used Plackett-Burman experimental design to assess the influence of enzymes of nematophagous fungi versus Strongyloides westeri and trichostrongylides larvae and Platynosomum fastosum eggs. The variables studied in the Plackett-Burman design were the proteases and chitinases of AC001 or VC4 as destructive agents of S. westeri and trichostrongylides larvae, and P. fastosum eggs. All tested enzymes had a significant effect (P < 0.05) on the destruction of S. westeri larvae. Furthermore, only VC4 and AC001 proteases showed a significant effect (P < 0.05) on the destruction of trichostrongylides larvae. On the other hand, chitinases of VC4 showed the highest significance (P < 0.05) on the destruction of P. fastosum eggs. It is proposed that statistical planning for the use of enzymes derived from nematophagous fungi is a viable way to elucidate some questions about their mechanism of action.

Changes in the lipid profile of Bradybaena similaris (Férussac, 1821) (Gastropoda, Xanthonychidae) during the development of Eurytrema coelomaticum (Giard and Billet, 1892) (Digenea, Dicrocoeliidae).

The effect of experimental exposure of Bradybaena similaris by Eurytrema coelomaticum on the cholesterol and triglycerides total levels circulating in the hemolymph and the neutral lipids in the digestive gland-gonad (DGG) complex of the host snail were studied. In this study, snails were dissected after one, two, and three months of infection to collect the hemolymph and DGG to measure the cholesterol and triacylglycerol levels in the hemolymph and neutral lipid fractions in the tissues. The results for the hemolymph showed that the infection by this trematode resulted in a significant decrease in the concentrations of triacylglycerol during all periods analyzed, as well as, increase in the levels of cholesterol observed after the second and third months of study. This decrease suggests the possible use of triacylglycerol by both parasite and host as alternative substrate in maintaining their energy metabolisms. In parallel, the increase in the contents of cholesterol results from a severe cellular disorganization in snail, especially DGG, as a consequence of the intense plastic processes showed by parasite. Additionally, changes in the neutral lipid profile in the DGG of the infected snails were observed, indicating the importance of these molecules for successful infection.

Keys to the species of Athesmia Loss, 1899 (Digenea: Dicrocoeliidae: Dicrocoeliinae), with the description of a new species from the clapper rail, Rallus longirostris Boddaert (Gruiformes: Rallidae), from Galveston, Texas, U.S.A.

Eleven specimens of a previously undescribed species of Athesmia Looss, 1899 were recovered from six clapper rails, Rallus longirostris Boddaert (Rallidae), collected from November, 1984 through October, 1995 from the Galveston, Texas area of the Gulf of Mexico. Species of Athesmia can be divided into two body types based on the posterior extent of the ceca relative to the vitelline field (vitellarium): the attilae type where the ceca may be uneven, but they both extend at least to near the level of the posterior margin of the vitelline field, or more commonly surpass the vitelline field posteriorly and the heterolechithodes type where the cecum on the side of the vitelline field terminates well above the posterior margin of the vitelline field, usually near its anterior extremity, while the cecum opposite the vitelline field extends at least to the level of the posterior margin of the vitelline field, or more commonly surpasses the vitelline field posteriorly. Athesmia ralli n. sp. is assigned to the attilae type. The new species is most similar to Athesmia butensis Petri, 1942, but differs from this species by having a longer space from posterior testis to ovary (600-790 compared to less than 200), which represent a larger percentage of the total body length (7-8% compared to 2%) and a larger maximum egg size (47 by 29 compared to 42 by 25). The new species further differs from A. butensis by having a somewhat larger body, a longer forebody and the vitelline field reaches posteriorly to the posterior third of the body in the new species but is confined to the middle third of the body in A. butensis. A key to species also is provided.

Parasites, primates, and ant-plants: clues to the life cycle of Controrchis spp. in black howler monkeys (Alouatta pigra) in southern Belize.

The purpose of this study was to investigate the prevalence, intensity, and possible transmission routes of the trematode, Controrchis spp. (Dicrocoeliidae), in a population of black howler monkeys (Alouatta pigra) near Monkey River, Belize. Alouatta pigra are arboreal primates that are typically folivorous and frugivorous. Controrchis is a dicrocoeliid trematode and, as such, should require a gastropod and an ant (Formicidae) intermediate host for transmission. From January to July 2005 and February 2006 to June 2007, we collected fecal samples and focal animal data from 18 individual primates in four social groups. Feces were stored in either 10% buffered formalin or 95% ethanol and examined using a double-centrifugation sugar-flotation technique. The prevalence of Controrchis spp. was 89%, and the mean intensity was 2.29 eggs per gram (epg), with a range of 1.00-6.57 epg. A general linear mixed model to examine the effect of sex, rainfall, and time spent feeding on various plant species, while controlling for individual and group identity, revealed that both group and the amount of time spent feeding on trumpet trees (Cecropia peltata) by individuals predicted the prevalence and intensity of Controrchis spp. infestation. Cecropia peltata has a mutualistic relationship with Azteca spp. ants and constitutes an important food source for A. pigra. Our findings provide strong, circumstantial evidence that A. pigra are infected with Controrchis spp. through the ingestion of metacercariae in Azteca spp. when feeding on C. peltata. Because C. peltata is a pioneer tree species and typically occurs in disturbed forests, results from this study suggest an important link between habitat disturbance and parasitism in a wild mammal.

Natural infection of Helix aspersa (Mollusca: Pulmonata) by Dicrocoeliidae (Digenea) larval stages in Izmir, Turkey.

In this study, the prevalence of larval stages of Dicrocoeliidae in the garden snail Helix aspersa Müller, 1774 commonly found in the vicinity of Izmir, Turkey was investigated and some of its histological and morphological features were determined. The molluscs were collected during the spring of 2005. As the result of the investigation, a land snail species, H. aspersa, was found to be an intermediate host in the life cycle of Dicrocoeliidae and it had a prevalence of 0.97 % in the study area. In the present study, H. aspersa has been reported for the first time as an intermediate host of Dicrocoeliid species. The prevalence of infection was highest in March.