Brachylaimiasis: Brachylaima spp. (Digenea: Brachylaimidae) Metacercariae Parasitizing the Edible Snail Cornu aspersum (Helicidae) in Spanish Public Marketplaces and Health-Associated Risk Factors

Potential intermediate hosts of Angiostrongylus cantonensis in the European Mediterranean region (Mallorca, Spain)

Angiostrongylus cantonensis is the main etiological agent of eosinophilic meningitis, a disease that often leads to severe neurological manifestations in mammals and birds. In recent years, the prevalence of this zoonotic nematode has dramatically increased as it expands into new territories beyond its native range in Southeast Asia and the Pacific Basin.Its arrival to Europe, the last continent to be invaded, has raised many questions concerning the parasite's life cycle, particularly in the Mediterranean region, where it is now endemic. This study aims to collect evidence about intermediate hosts (snail and slug species) involved in the transmission of the A. cantonensis in Mallorca. We have conducted a systematic surveillance of gastropods within 2 km radius areas, surrounding the specific locations where infected hedgehogs were found. We employed a sequence-based detection approach that included a species-specific PCR amplification followed by DNA sequencing of the internal transcribed spacer I (ITS-1). This conservative approach was essential to avoid cross reactions with the numerous metastrongylid species known to be circulating in Mallorca. Overall, we collected and identified 398 gastropods belonging to 17 species, of which 11% tested positive for A. cantonensis. These gastropods were collected from touristic settlements to agricultural lands. Five gastropod species: Theba pisana, Cornu aspersum, Deroceras reticulatum, Milax gagates and Otala lactea, had been previously incriminated as A. cantonensis intermediate hosts, while 6 species: Papillifera papillaris, Cochlicella acuta, Eobania vermiculata, Ganula lanuginosa, Milax nigricans and Rumina decollata, are newly recorded hosts. The findings of this study have important epidemiological implications, and further measures are discussed to prevent neuroangiostrongylosis cases.

Nematodes and trematodes associated with terrestrial gastropods in Nottingham, England

A parasitological survey of terrestrial slugs and snails was conducted at popular dog walking locations across the city of Nottingham, with the intensions of finding gastropods infected with parasites of medical (or veterinary) importance such as lungworm (metastrongyloid nematodes) and trematodes. A total of 800 gastropods were collected from 16 sites over a 225 km2 area. The extracted nematodes and trematodes were identified by molecular barcoding. Of the 800 gastropods collected, 227 were infected (172 had nematode infections, 37 had trematode infections and 18 had both nematode and trematode infections). Of the nematode infected gastropods genotyped, seven species were identified, Agfa flexilis, Angiostoma gandavense, Angiostoma margaretae, Cosmocerca longicauda, Phasmarhabditis hermaphrodita, Phasmarhabditis neopapillosa and an unknown Cosmocercidae species. Of the trematode infected gastropods genotyped, four species were identified, Brachylaima arcuate, Brachylaima fuscata, Brachylaima mesostoma and an unknown Plagiorchioidea species. No lungworm species were found within the city of Nottingham. To our knowledge, this study represents the first survey of gastropod-associated nematodes and trematodes in the East midlands of the United Kingdom.

Brachylaima spp. (Trematoda) parasitizing Cornu aspersum (Gastropoda) in France with potential risk of human consumption

The edible land snail Cornu aspersum, native to the Mediterranean coastlines of North Africa, is widely distributed on most continents and often invasive in areas where introduction is recent. This species could contribute to the geographic spread of parasites as demonstrated for Brachylaima spp. These cosmopolitan trematodes may represent a threat to human health, like in Australia where Brachylaima cribbi infects humans. In this study, we demonstrate for the first time the occurrence of Brachylaima spp. in two French populations of C. aspersum, Thorigné-Fouillard (Ille-et-Vilaine), and Arçais (Deux-Sèvres), with an overall prevalence of 10.4% (Thorigné-Fouillard) and 73.3% (Arçais), respectively and a metacercarial intensity on average three times higher in Thorigné-Fouillard (37) than in Arçais (11). Cornu aspersum may act as a first and second intermediate host, as demonstrated in Arçais. The morphometrics of metacercariae, particularly the great body length about 2 mm, discriminate our Brachylaima species from those already described in C. aspersum (B. cribbi in Australia, and B. aspersae, B. llobregatensis and B. mascomai in Europe). Molecular analysis, based on 28S and COI, suggests the occurrence of two species in our study, one of which is probably Brachylaima mesostoma, an intestinal parasite of passeriform birds described in Central Europe. We underline the need for further research to identify species of Brachylaima in France and measure the health hazard of consuming field-collected snails.

Brachylaima asakawai sp. nov. (Trematoda: Brachylaimidae), a rodent intestinal fluke in Hokkaido, Japan, with a finding of the first and second intermediate hosts

In the 1970's and 1980's, an unknown species of the genus Brachylaima (Trematoda: Brachylaimidae) had been recorded from the intestines of Rattus norvegicus and Apodemus speciosus in Hokkaido, Japan. The rodent fluke was characteristic in extending a bilateral vitellarium till the level of posterior margin of anterior testis and in keeping almost the same-sized spherical ovary and testes. In this study, the rodent fluke was rediscovered from A. speciosus, Apodemus argenteus, and Myodes rufocanus in Hokkaido. The resultant parasite collection enabled us to make a mitochondrial DNA (mtDNA) barcode for tracking its intermediate hosts. The metacercaria of the rodent fluke was detected frequently from the kidney of three species of land snails (Discus pauper, Succinea lauta, and Ainohelix editha). However, its sporocyst with cercariae was found only from the hepatopancreas of D. pauper, a fairly small snail. The wide-spectrum of the second intermediate host seems to increase the chance of transmitting the parasite to various mammals and birds. The use of indigenous land snails as the first and second intermediate hosts, the distinctiveness of the mtDNA sequence, and the characteristic morphology of all the developmental stages prompted us to propose Brachylaima asakawai sp. nov. for the rodent intestinal fluke in Hokkaido. The present field survey suggests that the life cycle of the new species is primarily dependent on a predator-prey relationship between rodents and D. pauper.