Comparison of diagnosis techniques for the protozoan parasite Bonamia ostreae in flat oyster Ostrea edulis

Balseiro, Pablo; Conchas, Ramón F.; Montes, Jaime; Gomez‐León, Javier; Novoa, Beatriz; Figueras, António

doi:10.1016/j.aquaculture.2006.05.014

Cited by 26 publications

(22 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Histology was the diagnostic test with the lowest values of sensitivity but its high values of specificity support that it is a reliable technique to distinguish Bonamia ostreae and B. exitiosa with appropriate training. The sensitivity of the 2 OIE-recommended tests involved in this study have been evaluated in previous reports through comparison with other diagnostic techniques (Carnegie et al 2000, Diggles et al 2003, Balseiro et al 2006, Corbeil et al 2006b, Marty et al 2006, Lynch et al 2008, Robert et al 2009). …”

Section: Discussionmentioning

confidence: 99%

“…Light microscopy-based methods such as examination of gills or heart tissue imprints or histological sections have been described, but these methods are slow (especially the latter technique) and require a trained observer to screen the samples, because of the similar morphological characteristics between the species (Hine et al 2001, Abollo et al 2008. Numerous researchers have noticed low sensitivity and specificity of these light microscopy techniques (O'Neill et al 1998, Culloty et al 2003, Diggles et al 2003, da Silva & Villalba 2004, Balseiro et al 2006, Marty et al 2006). Molecular techniques used for identification of Bonamia spp., such as PCR or in situ hybridization, have been proven to be more sensitive than microscopical techniques, but most of them lack specificity for species identification.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Species-specific diagnostic assays for Bonamia ostreae and B. exitiosa in European flat oyster Ostrea edulis: conventional, real-time and multiplex PCR

Ramilo¹,

Navas²,

Villalba³

et al. 2013

Dis. Aquat. Org.

View full text Add to dashboard Cite

Bonamia ostreae and B. exitiosa have caused mass mortalities of various oyster species around the world and co-occur in some European areas. The World Organisation for Animal Health (OIE) has included infections with both species in the list of notifiable diseases. However, official methods for species-specific diagnosis of either parasite have certain limitations. In this study, new species-specific conventional PCR (cPCR) and real-time PCR techniques were developed to diagnose each parasite species. Moreover, a multiplex PCR method was designed to detect both parasites in a single assay. The analytical sensitivity and specificity of each new method were evaluated. These new procedures were compared with 2 OIE-recommended methods, viz. standard histology and PCR-RFLP. The new procedures showed higher sensitivity than the OIE recommended ones for the diagnosis of both species. The sensitivity of tests with the new primers was higher using oyster gills and gonad tissue, rather than gills alone. The lack of a 'gold standard' prevented accurate estimation of sensitivity and specificity of the new methods. The implementation of statistical tools (maximum likelihood method) for the comparison of the diagnostic tests showed the possibility of false positives with the new procedures, although the absence of a gold standard precluded certainty. Nevertheless, all procedures showed negative results when used for the analysis of oysters from a Bonamia-free area.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Species-specific diagnostic assays for Bonamia ostreae and B. exitiosa in European flat oyster Ostrea edulis: conventional, real-time and multiplex PCR

Ramilo¹,

Navas²,

Villalba³

et al. 2013

Dis. Aquat. Org.

View full text Add to dashboard Cite

show abstract

“…Heart imprints have been used as a diagnostic tool for the detection of B. ostreae in numerous studies (Martin et al 1993;Hervio et al 1995;Culloty and Mulcahy 1996;Naciri-Graven et al 1998;Culloty et al 1999;Culloty et al 2004;Lynch et al 2005) (Annex 1). However, Balseiro et al (2006) reported that the PCR methodology showed a higher sensitivity than histological and cytological studies particularly at the early stages of infection. An advantage of the heart imprint method is that a semi-quantitative scale for the level of infection with the parasite can be used (B0 − , B0 + , B0 ++ or B0 +++ ) contrary to a PCR assay in which the band is either present or absent.…”

Section: Detection Of Bonamia Ostreaementioning

confidence: 99%

Bonamia ostreae-induced mortalities in one-year old European flat oystersOstrea edulis: experimental infection by cohabitation challenge

Lallias

Arzul

Heurtebise

et al. 2008

Aquat. Living Resour.

View full text Add to dashboard Cite

-Bonamiosis is a parasitic disease (causative agent: Bonamia ostreae) affecting the European flat oyster Ostrea edulis, responsible for a drastic decline in its aquaculture production. Selective breeding programs for resistance to bonamiosis have been undertaken to counter this disease. In the present study, a 6-month cohabitation challenge experiment was performed in order to transmit the disease from wild oysters injected with the parasite to two tested families of oysters (20 and 8-month old at the beginning of the experiment, with different genetic backgrounds) originating from a selective breeding program developed by IFREMER in France. Mortalities were checked daily and ventricular heart smears were performed on dying or moribund oysters to detect the level of infection by B. ostreae. Mortality started after 4 months of cohabitation in the tested oysters. The cumulative mortalities after 6 months were 58% for the wild oysters, 9% for Family 1 (20-month old) and 20% for Family 2 (8-month old). In the dying oysters, the parasite could be detected in 67% of the wild oysters, 68% of Family 1 and 89% of Family 2. It was detected in only 11% of the surviving oysters of Family 2. The mortality and the level of infection by the parasite were significantly higher in Family 2 than in Family 1. Our results demonstrate that prespawning oysters as young as 1 year-old can become infected with the parasite and, most importantly, can die from bonamiosis. This result is inconsistent with the commonly accepted critical age of 2 years-old for the disease development. Additionally, no clear relationship between shell length and level of infection was observed. We also review the different methods for infection of the European flat oyster O. edulis with B. ostreae under experimental conditions and their main results. Key words:Ostrea edulis / Bonamia ostreae / Cohabitation experiment / Transmission / Heart smear Résumé -Mortalités induites par Bonamia ostreae chez des huîtres plates européennes Ostrea edulis âgées d'un an : infection expérimentale par cohabitation. La bonamiose est une maladie parasitaire (agent causal : Bonamia ostreae) affectant l'huître plate européenne Ostrea edulis, responsable d'un déclin drastique de sa production aquacole. Des programmes de sélection pour la résistance à la bonamiose ont été entrepris pour contrer cette maladie. Dans cette étude, une expérience de 6 mois d'infection par cohabitation a été réalisée de manière à transmettre la maladie à partir d'huîtres sauvages injectées avec le parasite vers deux familles testées d'huîtres (âgées de 20 et 8 mois en début d'expérience, avec des origines génétiques différentes) issues du programme de sélection développé par IFREMER en France. Les mortalités ont été vérifiées quotidiennement et des frottis de coeur ventriculaire réalisés sur les huîtres mortes ou moribondes pour détecter le niveau d'infection par B. ostreae. La mortalité a commencé chez les huîtres testées après 4 mois de cohabitation. Les mortalités cumulées après 6 mois étaient...

show abstract

“…In some studies, cytology was found to be more sensitive than histology (Diggles et al 2003, Lynch et al 2008. In others, histology was more sensitive (Zabaleta & Barber 1996, Balseiro et al 2006 or the methods were comparable (da Silva & Villalba 2004). For both assays, skilled and trained personnel are needed, and differences between the assays might reflect the background and particular capabilities of the laboratories.…”

Section: Diagnosticsmentioning

confidence: 99%

Bonamia parasites: a rapidly changing perspective on a genus of important mollusc pathogens

Engelsma¹,

Culloty²,

Lynch³

et al. 2014

Dis. Aquat. Org.

View full text Add to dashboard Cite

Organisms of the genus Bonamia are intracellular protistan parasites of oysters. To date, 4 species have been described (B. ostreae, B. exitiosa, B. perspora and B. roughleyi), al though the status of B. roughleyi is controversial. Introduction especially of B. ostreae and B. exitiosa to naïve host populations has been shown to cause mass mortalities in the past and has had a dramatic impact on oyster production. Both B. ostreae and B. exitiosa are pathogens notifiable to the World Organisation for Animal Health (OIE) and the European Union. Effective management of the disease caused by these pathogens is complicated by the extensive nature of the oyster production process and limited options for disease control of the cultured stocks in open water. This review focuses on the recent advances in research on genetic relationships between Bonamia isolates, geographical distribution, susceptible host species, diagnostics, epizootiology, host− parasite interactions, and disease resistance and control of this globally important genus of oyster pathogens.KEY WORDS: Bonamia ostreae · Bonamia exitiosa · Oyster disease · Phylogenetics · Geographical spread · Diagnostics · Epizootiology · Host−parasite interaction · Bonamiosis Resale or republication not permitted without written consent of the publisher Contribution to DAO Special 7 'Microcell parasites of molluscs'

show abstract

Comparison of diagnosis techniques for the protozoan parasite Bonamia ostreae in flat oyster Ostrea edulis

Cited by 26 publications

References 43 publications

Species-specific diagnostic assays for Bonamia ostreae and B. exitiosa in European flat oyster Ostrea edulis: conventional, real-time and multiplex PCR

Species-specific diagnostic assays for Bonamia ostreae and B. exitiosa in European flat oyster Ostrea edulis: conventional, real-time and multiplex PCR

Bonamia ostreae-induced mortalities in one-year old European flat oystersOstrea edulis: experimental infection by cohabitation challenge

Bonamia parasites: a rapidly changing perspective on a genus of important mollusc pathogens

Contact Info

Product

Resources

About