An ovarian infection in the Iwagaki oyster, Crassostrea nippona, with the protozoan parasite Marteilioides chungmuensis

Marteilia spp. parasites in bivalves: A revision of recent studies

“…In addition to loss of oyster marketability, the parasite may cause spawning failure of oysters (Ngo et al, 2003); therefore, a decrease in the oyster resource and failure of artificial spat production are of concern to the industry. Infection of M. chungmuensis has been reported in other edible oyster species, such as C. nippona and C. ariakensis, but prevalences in these species are much lower than in Pacific oysters and the disfigured appearance has not been reported (Itoh et al, 2004b;Limpanot et al, 2013), indicating that M. chungmuensis is not significant threat to the market for these oyster species.…”

“…However, sensitivity of this PCR diagnosis is not sufficient for practical use and nested-PCR using another primer pair, OPF3/OPR3, is recommended to increase sensitivity (Itoh et al, 2003b). This PCR protocol was used for detection of the parasite in male oysters (Itoh et al 2004a), diagnosis of various bivalves (Itoh et al 2004b;Limpanot et al 2013;Sühnel et al 2014) and determination of invasion period of the parasite (Tun et al 2008b). In order to morphologically characterise M. chungmuensis cells outside oyster oocytes, in situ hybridisation probes for M. chungmuensis, MCSP-01, MCSP-05 and 6-R, were developed (Itoh et al, 2003a).…”

Non-specific Defensive Factors of the Pacific OysterCrassostrea gigasagainst Infection withMarteilioides chungmuensis: A Flow-Cytometric Study

“…Infections with Marteilioides chungmuensis , a paramyxean protozoa affecting the normal oviposition and development of fertilized eggs and impairing the product quality by damaging the visual attractiveness have been identified as causative factors in the reduced aquaculture production of oysters, C. gigas [2]. Studies of this ovarian parasite included the assessment of microstructures [3], process of spore formation [4], initial infection route[5], rate of infection [2,4,6,7], development of diagnostic methods [8,9], pathogenicity [2,9], biochemical examinations [6], and effects of environmental factors [10,11]. A variety of such studies have been conducted in Korea and Japan.…”

Detection of a parasitic amoeba (Order Dactylopodida) in the female gonads of oysters in Brazil

“…This parasite can affect oocytes in large areas of the reproductive follicles, which causes irregular enlargement of the infected gonadal tissues, giving the infected oyster a nodular appearance suggestive of multiple tumours. Originally described in C. gigas from Korea (Comps et al 1987), it also occurs in C. gigas and C. nippona from Japan (Itoh et al 2004b), and a similar parasite was reported from the ova of C. echinata from Australia (Hine & Thorne 2000). A Marteilioides-like parasite was also reported at low prevalence (1.6%) from the oocytes of Manila clams Venerupis (=Tapes) philippinarum, in coastal areas of Korea (Lee et al 2001).…”