Microsporidia of the genera Thelohania (Thelohaniidae) and Ameson (Pereziidae) in two species of lithodid crabs from the Sea of Okhotsk

Ameson metacarcini sp. nov. (Microsporidia) infecting the muscles of Dungeness crabs Metacarcinus magister from British Columbia, Canada

“…The spores are most similar in size to those reported from A. atlanticum (1.8 × 1.4 µm vs. 2.0 × 1.5 µm); however, the latter species was described from a different host (C. pagurus) from the French Atlantic coastline. Few other morphological characters appear to be useful, and these characters are generally comparable to other reported but undescribed species in the genus (Shields & Wood 1991, Kiryu et al 2009, Ryazanova & Eliseikina 2010. Spores of A. metacarcini had hair-like villous projections that have previously been observed in other Ameson species (Vivarès & Sprague 1979, Vivarès & Azevedo 1988, Kiryu et al 2009, Ryazanova & Eliseikina 2010, Stentiford et al 2013b).…”

“…Few other morphological characters appear to be useful, and these characters are generally comparable to other reported but undescribed species in the genus (Shields & Wood 1991, Kiryu et al 2009, Ryazanova & Eliseikina 2010. Spores of A. metacarcini had hair-like villous projections that have previously been observed in other Ameson species (Vivarès & Sprague 1979, Vivarès & Azevedo 1988, Kiryu et al 2009, Ryazanova & Eliseikina 2010, Stentiford et al 2013b). Vivarès & Azevedo (1988) used the projections on the spore to separate the genera Ameson from Perezi within the family Pereziidae (see also Canning & Vávra 2000).…”

“…Few studies have considered sexual differences in the prevalence levels in microsporidian infections in decapod hosts. Of the limited number that have, prevalence levels were reported as approximately equal between host sexes (Parsons & Khan 1986, Herbert 1988, Skurdal et al 1990, Ryazanova & Eliseikina 2010. However, sexual differences are known from microsporidian infections in amphipod hosts where the parasites are known to be transmitted vertically (e.g.…”

Widespread infection of Areospora rohanae in southern king crab ( Lithodes santolla ) populations across south Chilean Patagonia

“…Disentangling the relationship between sex and prevalence is particularly relevant in those cases where hosts are selectively exploited. For example, several crab fisheries focus on large males, so pathogen-induced mortality would have differential effects on the economic activity if parasitosis is either sex-dependent or independent [3,14].…”

“…These parasites develop massive accumulations of spores that destroy and replace the host’s muscular tissue—once the musculature is fully replaced, the disease expands to other organs and kills the host [19]. In general, microsporidian parasites can have a high pathogenicity, and when they affect commercially important hosts such as wild populations of crustaceans under exploitation [3,14,19], the spread of the disease can have severe societal consequences. In this line, lithodid crabs host a limited number of microsporidian parasites and sustain important fisheries, with 2000 and 4000 t yr −1 captured in the Northern and Southern Hemisphere, respectively [20,21].…”