Occurrence of Perkinsus Species (Protozoa, Apicomplexa) from Manila Clam Tapes philippinarum in Japan.

Maeno, Yukio; Yoshinaga, Tomoyoshi; Nakajima, Kazuhiro

doi:10.3147/jsfp.34.127

Cited by 20 publications

(23 citation statements)

References 10 publications

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“…Perkinsus-like parasites have been reported from a large number of molluscan species from Australian waters (Goggin and Lester 1987;Hine and Thorne 2000). In the Pacific Ocean, Perkinsus-like parasites have been associated with mass mortalities of the Manila clam Tapes philippinarum in South Korea (Choi and Park 1997;Park et al 1999;Park and Choi 2001) and have been detected in clams from Japan (Hamaguchi et al 1998;Maeno et al 1999;Choi et al 2002) and China (Liang et al 2001) 412 A. Villalba et al: Aquat.…”

Section: Historical Perspectivementioning

confidence: 99%

Perkinsosis in molluscs: A review

Villalba

Reece

Ordás

et al. 2004

Aquat. Living Resour.

303

243

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-The genus Perkinsus includes protistan parasites infecting marine molluscs throughout the world, some of which are associated with mass mortalities. Life cycle involves vegetative proliferation within the host, by which a cell named trophozoite undergoes successive bipartitioning. Other stages have been observed in vitro or in vivo, depending on the species: hypnospore, zoosporangium and zoospore. Molecular taxonomy supports a close affinity between dinoflagellates and Perkinsus spp. Six species of Perkinsus are currently considered valid: P. marinus, P. olseni, P. qugwadi, P. chesapeaki, P. andrewsi and P. mediterraneus. Histology and, above all, incubation of host tissues in Ray's fluid thioglycollate medium (RFTM) are classic diagnostic methods. In addition, more sensitive and quicker molecular diagnostic techniques based on either immunoassays or PCR have been developed for Perkinsus spp. Epizootiological studies have shown a marked influence of water temperature and salinity on P. marinus infection in oysters Crassostrea virginica, thus determining parasite geographical range and temporal disease dynamics (seasonality). In vitro cultures have been established for four Perkinsus spp. Immune response to infection varies depending on host and involves phagocytosis or encapsulation of the parasite cells by host haemocytes. A polypeptide is secreted by clamTapes philippinarum haemocytes that could kill the parasite. In vitro cultured P. marinus cells secrete proteases that are likely involved in degradation of host tissues. P. marinus can suppress the toxic oxygen radicals produced by host haemocytes. In addition to host death, sublethal effects caused by Perkinsus spp. (reduction of fecundity, growth, and condition) may have significant ecological and economic implications. Various strategies have been assayed to mitigate the consequences of P. marinus epizootics on the oyster industry: modifications of management/culture procedures, selective breeding to obtain resistant oyster strains, and the use of triploid oysters and allochthonous oyster species. Some chemotherapeutants have been proved to inhibit or kill parasite cells in vitro.

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Section: Historical Perspectivementioning

confidence: 99%

Perkinsosis in molluscs: A review

Villalba

Reece

Ordás

et al. 2004

Aquat. Living Resour.

303

243

View full text Add to dashboard Cite

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“…Because of the earlier association of perkinsosis with shellfish mortality, the detection of Perkinsus-like parasites in clams T. decussatus from Galicia (NW Spain) in the late 1980s (Figueras et al 1992) was considered a threat to the clam industry of the region. Perkinsosis has also been detected in other venerid clams on the Pacific coasts, including the Manila clam T. philippinarum in South Korea (Choi & Park 1997, Park et al 1999, Park & Choi 2001, Japan (Hamaguchi et al 1998, Maeno et al 1999 and China (Liang et al 2001), and the surf clam Paphia undulata in Thailand (Leethochavalit et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Study of perkinsosis in the carpet shell clam Tapes decussatus in Galicia (NW Spain). II. Temporal pattern of disease dynamics and association with clam mortality

Villalba¹,

Casas²,

López³

et al. 2005

Dis. Aquat. Org.

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Temporal dynamics of the infection by Perkinsus olseni in a clam (Tapes decussatus) bed was studied over 5 yr (March 1996 to December 2000. Diagnostic techniques were compared to assess their suitability for epizootiological purposes. A technique based on incubation of 2 gill lamellae in Ray's fluid thioglycollate medium (RFTM) was more sensitive, quicker and cheaper than examination of histological sections. Incubation of the whole-clam soft tissues in RFTM allowed detection of very light infections that were not detected with incubation of only 2 gill lamellae. Nevertheless, the correlation between the infection intensity estimated by both RFTM incubations was high. Infection intensity was significantly and positively correlated with clam size/age. No infected clam smaller than 20 mm was found. There was an annual pattern of infection involving lower mean infection intensity and prevalence in winter and higher values for both variables from spring to autumn, with 2 main annual peaks in spring and late summer-early autumn. This temporal pattern was significantly associated with the seawater temperature. The annual spring peak of infection intensity occurred when seawater temperature was around 15°C. Monthly mortality in the clam bed peaked in spring and summer -after peaks of P. olseni infection intensity and concurrently with high seawater temperature. A comparison of percentage mortality between clams from 2 sources (a perkinsosis-affected and a non-affected area) placed in the same clam bed revealed significantly higher mortality in the clams originating from the perkinsosis-affected area. KEY WORDS: Perkinsus olseni · Tapes decussatus · Infection dynamics · Epizootiology · Diagnosis · Disease · Mortality · Temperature Resale or republication not permitted without written consent of the publisherDis Aquat Org 65: [257][258][259][260][261][262][263][264][265][266][267] 2005 The parasite affecting Galician clams was identified as Perkinsus atlanticus (Robledo et al. 2000, Casas et al. 2002b. Genetic studies suggested that P. atlanticus is also the etiologic agent of perkinsosis in Tapes philippinarum from Japan (Hamaguchi et al. 1998) and South Korea and that of P. undulata from Thailand (Leethochavalit et al. 2003). Molecular taxonomy supports close proximity between P. olseni and P. atlanticus (Goggin 1994, Robledo et al. 2000, Casas et al. 2002a and both were recently considered to be conspecific, with P. olseni taking precedence (Murrell et al. 2002). Therefore, P. atlanticus is referred to herein as P. olseni. P. olseni was originally described as a parasite of the abalone Haliotis ruber in the south of Australia (Lester & Davis 1981). P. olseni was blamed for severe mortalities in H. laevigata (O'Donoghue et al. 1991, Goggin & Lester 1995 and was detected in the pearl oyster Pinctada maxima (Norton et al. 1993). Furthermore, Perkinsus-like parasites occur in numerous molluscan species in Australian waters (Goggin & Lester 1987, Hine & Thorne 2000. Synonymy of P. olseni and P. atlanticus sup...

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“…often result in delayed growth, low CI, and retarded reproduction in the host animals (see review by Ford and Tripp, 1996;Park et al, 2006b). In Japan, Hamaguchi et al (1998) and Maeno et al (1998) first reported Perkinsus infection among R. philippinarum in Kumamoto, Hiroshima and the western Japan. According to Hamaguchi et al (1998), DNA sequences of the ITS of Perkinsus isolated from clams were identical to those of P. olseni (=P.…”

Section: Perkinsus Infectionmentioning

confidence: 96%