Research/Eimeria cryopreservation and differentiation
From Poultry Hub
Title: Eimeria cryopreservation and differentiation
Project Leader: Rima Youil at Bioproperties funded by Poultry CRC (Project 07-24)
Duration of Project: 1 June 2007 to 31 December 2008
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Project overview
The genus Eimeria, belonging to the phylum Apicomplexa, encompasses intracellular protozoan parasites responsible for coccidiosis disease in poultry and other birds. Multiplication of these parasites within the intestinal tract causes tissue damage that can significantly impact nutrient absorption and ultimately lead to dehydration and blood loss (bloody diarrhoea). Poultry mortalities due to coccidiosis are estimated to be between 20% - 50% but can rise as high as 80% during epidemics, resulting in significant economic losses worldwide (Kinung’hi S.M. et al., 2004). Current practices to curb this disease rely on administration of anti-coccocidial drugs via feed. However, long term use of these drugs can lead to the development of drug-resistance strains. Live vaccine approaches have proven to be highly effective in the control of this disease.
Project objectives
The Project’s two major objectives are to:
- identify and implement ‘best practice’ in cryopreservation of Eimeria spp. commercial vaccine and research seeds; and
- identify vaccine specific markers to differentiate vaccine strains from their parent strains.
Project progress
Several aspects for the preservation of Eimeria vaccine master seeds are being studied in this project:
- identifying the optimal cryopreservative formulation
- developing procedures for oocysts preparation prior to freezing
- developing a program for the cryo freezing unit
- Testing the new cryo freeze conditions on each vaccine strains
- Determining long-term stability of the master seeds
Currently, three formulations are being tested side by side. The procedure for oocyst preparation and a program for freezing down seeds have been developed. Fresh antigen from each of the vaccine species is currently being prepared for testing. Long-term stability will follow.
The strain differentiation project has required considerable set up with respect to both equipment and materials. A novel approach is being tested in addition to standard genomic methods for identifying differences between strains.
