1. Bonamia ostreae and the
oyster culture industry

2. • Bonamia ostreae .
• Why does it matter?
• Current knowledge.
• Mitigating oyster loss.
• Effect of physiological stress on the development of bonamiasis in O. edulis.
OVERVIEW

3. INTRODUCTION

4. Bonamia ostreae
• Haplosporidian parasite1.
• Infects haemocytes of Ostrea edulis2.
• Haemocytes play an important role in O. edulis immune system3.
• Direct transmission2,4.
• Rarely obvious signs of infection except high mortalities5.

5. Why do we care?
• B. ostreae emerged in Europe during late 1970’s and early 1980’s.
• Studies indicated it originated from California6.
• Causes mass mortalities.
• Impossible to eradicate7.
• Resulted in decline in European O. edulis industry8.

6. FAO
2014

7. Current Knowledge
• Detection
• Physiological

8. Detection
• Histological methods slow and require a trained observer to screen samples10.
• Sensitive tests much needed in industry for early diagnosis9.
• Sensitive techniques have been developed1,10,11,12.
• Cochennec et al. used PCR and in situ hybridisation to detect B. ostreae for first
time using DNA techniques in 20001.
• Carnegie et al. developed PCR protocol based on 18s ribosomal DNA sequences11.

9. Carnegie et al.
2000

10. Physiological
• Seasonal variation in prevalence13.
• Disease resistance in some oysters14.
• Critical age of disease development.
• Gender does not affect prevalence15.
• Scope for growth in oysters greatly reduced at low salinities regardless of temperature16.
• Adaptive capacity of cellular processes in oysters reduced at low salinities17.

11. Hauton et al. 1998

12. Hauton et al. 1998

13. Mitigating oyster losses
• Screening of spat.
• Management practices (CEFAS).
• Introduction of resistant populations2.

14. CEFAS Guidelines
• Rejection of undocumented oyster batches.
• Destroy unwanted oysters on land.
• Avoid unnecessary stress.
• Do not deposit in unaffected areas.
• Clear infected lays.
Woolmer et al. 2011

15. Aims and objectives of current study
• Assess the effect of temperature and salinity on B. ostreae prevalence
in O. edulis.
• Expose oysters to various temperature-salinity combinations.
• Use PCR and nested PCR to detect low-level infections.
• Use histological staining to obtain semi-quantitative data on the level
of infection.

16. Conclusions
• B. ostreae – haplosporidian parasite of haemocytes.
• Responsible for decline in European O. edulis industry.
• Development of sensitive detection methods.
• Physiological responses of O. edulis.
• Oyster loss mitigation.
• Future research.

17. References
1. Cochennec, N., Le Roux, F., Berthe, F., & Gerard, a. (2000). Detection of Bonamia ostreae based on small subunit ribosomal probe. Journal of invertebrate pathology. 76(1), pp.26–32.
2. Woolmer, A.P., Syvret, M. & FitzGerald A., 2011. Restoration of Native Oyster, Ostrea edulis, in South Wales: Options and Approaches. CCW Contract Science Report No: 960, 93 pp.
3. Cheng, T.C.,1981. Bivalves. In: Ratcliff, N.A., Rowley, A.F. (Eds.), Invertebrate Blood Cells. Academic Press, London, pp. 233–330.
4. Arzul, I., Langlade, A., Chollet, B., Robert, M., Ferrand, S., Omnes, E., Lerond, E., Couraleau, Y., Joly, J., François, C. & Garcia, C. (2011). Can the protozoan parasite Bonamia ostreae infect larvae of flat oysters
Ostrea edulis? Veterinary Parasitology. 179 (1-3), pp. 69-76
5. Cao, A., Fuentes, J., Comesaña, P., Casas, S.M. & Villalba, A. (2009). A proteomic approach envisaged to analyse the bases of oyster tolerance/resistance to bonamiasis. Aquaculture. 295, pp.149-156.
6. Elston, R.A., Kent, M.L. & Wilkinson, M.T. (1987). Resistance of Ostrea edulis to Bonamia ostreae infection. Aquaculture. 64, pp.237-242.
7. Van banning, P. (1985). Control of Bonamia in Dutch oyster culture. In: Ellis, A.E. (ed.) Fish and shellfish pathology. Proceedings of a symposium, 20-23 September 1983, at Plymouth Polytechnik, Plymouth, U.K.
Academic Press, London, pp. 393-396.
8. FAO 2004-2014.
Cultured Aquatic Species Information Programme. Ostrea edulis. Cultured Aquatic Species Information Programme. Text by Goulletquer, P. In: FAO Fisheries and Aquaculture Department [online]. Rome.
Updated 1 January 2004. [Cited 31 May 2014].
9. Lynch, S.A., Armitage, D.V., Wylde, S., Mulcahy, M.F. & Culloty, S.C. (2005). The susceptibility of young prespawning oysters, Ostrea edulis to Bonamia ostreae. Journal of Shellfish Research. 24 (4), pp.1019-1025.
10. Ramilo, A., Navas, J. I., Villalba, A., & Abollo, E. (2013). Species-specific diagnostic assays for Bonamia ostreae and B. exitiosa in European flat oyster Ostrea edulis: conventional, real-time and multiplex PCR.
Diseases of aquatic organisms. 104(2), pp.149–61
11. Carnegie, R B, Barber, B. J., Culloty, S. C., Figueras, a J., & Distel, D. L. (2000). Development of a PCR assay for detection of the oyster pathogen Bonamia ostreae and support for its inclusion in the Haplosporidia.
Diseases of aquatic organisms. 42(3), 199–206.
12. Carnegie, Ryan B, Barber, B. J., & Distel, D. L. (2003). Detection of the oyster parasite Bonamia ostreae by fluorescent in situ hybridization. Diseases of aquatic organisms. 55(3), pp.247–52.
13. Van Banning, P. 1990. The life cycle of the oyster pathogen Bonamia ostreae with a presumptive phase in the ovarian tissue of the European flat oyster, Ostrea edulis.Aquaculture 84, 189-192.
14. Elston, R.A., Kent, M.L. & Wilkinson, M.T. (1987). Resistance of Ostrea edulis to Bonamia ostreae infection. Aquaculture. 64, pp.237-242.
15. Culloty, S.C. & Mulcahy, M.F. (1996). Eason-, age-, and sex-related variation in the prevalence of bonamiasis in flat oysters (Ostrea edulis) on the south coast of Ireland. Aquaculture. 144, pp.53-63.
16. Hutchinson, S. & Hawkins, L.E. (1992). Quantification of the physiological responses of the European flat oyster Ostrea edulis to temperature and salinity. J. Moll. Stud. 58, pp. 215-226.
17. Hauton, C., Hawkins, L. ., & Hutchinson, S. (1998). The use of the neutral red retention assay to examine the effects of temperature and salinity on haemocytes of the European flat oyster Ostrea edulis (L).
Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology. 119(4), pp.619–623.