Submitted to: Avian Diseases
Publication Type: Review article
Publication Acceptance Date: 3/1/2005
Publication Date: 6/5/2005
Citation: Dallul, R.A., Lillehoj, H.S. 2005. Recent advances in immunomodulation and vaccination strategies against coccidiosis. Avian Diseases. 48:1-8. Interpretive Summary: Avian coccidiosis is caused by at least 6 different strains of Eimeria parasites and causes severe damage to the gut of chickens. Currently coccidiosis is controlled by prophylactic medication and vaccination with live commercial parasite vaccines. Due to increasing concerns of consumers on using chemicals in the food products, there is an increasing interest to develop drug-free methods to control coccidiosis. In this paper, ARS scientists review the current state-of-the-art in the coccidiosis vaccine development research and present new findings on the use of immunomodulators to enhance intestinal immune response against coccidiosis and other poultry diseases. In this paper, the authors propose various ways to devise new immunoenhancing strategies by modulating the host's own immune system. These strategies include using proteins which are naturally produced by host immune system such as cytokines and some antimicrobial products made by host cells which have known influence on the mucosal physical integrity and immune system. As proposed in this paper, various nutritional modulation of host immune response will lead a new way to devise safe, drug-independent control strategies against many poultry pathogens.
Technical Abstract: Coccidiosis is a ubiquitous intestinal protozoan infection of poultry seriously impairing the growth and feed utilization of infected animals. Conventional disease control strategies rely heavily on chemoprophylaxis costing the industry tremendously. Existing vaccines comprise live virulent or attenuated Eimeria strains with limited scope of protection against an ever evolving and widespread pathogen. The continual emergence of drug resistant strains of Eimeria, coupled with the increasing regulations and bans on the use of anticoccidial drugs in commercial poultry production, urges the need for novel approaches and alternative control strategies. Due to the complexity of the host immunity and the parasite life cycle, comprehensive understanding of host-parasite interactions and protective immune mechanisms becomes necessary for successful prevention and control practices. Recent progress in functional genomics technology would facilitate the identification and characterization of host genes involved in immune responses as well as parasite genes and proteins that eliciting protective host responses. This review will highlight recent developments in coccidiosis research and provide information on host immunity, immunomodulation, and the latest advances in live and recombinant vaccine development against coccidiosis. Such information will magnify our understanding of host-parasite biology, mucosal immunology, and design of future nutritional interventions and vaccination strategies for coccidiosis.