Vaccines against chicken coccidiosis with particular reference to previous decade: progress, challenges, and opportunities

Abstract

Chicken coccidiosis is an economically significant disease of commercial chicken industry accounting for losses of more than £10.4 billion (according to 2016 prices). Additionally, the costs incurred in prophylaxis and therapeutics against chicken coccidiosis in developing countries (for instance Pakistan according to 2018 prices) reached US $45,000.00 while production losses for various categories of chicken ranges 104.74 to US $2,750,779.00. The infection has been reported from all types of commercial chickens (broiler, layer, breeder) having a range of reported prevalence of 7-90%. The concern of resistance towards major anticoccidials has provided a way forward to vaccine research and development. For prophylaxis of chicken coccidiosis, live virulent, attenuated, ionophore tolerant strains and recombinant vaccines have been extensively trialed and commercialized. Eimeria antigens and novel vaccine adjuvants have elicited the protective efficacy against coccidial challenge. The cost of production and achieving robust immune responses in birds are major challenges for commercial vaccine production. In the future, research should be focused on the development of multivalent anticoccidial vaccines for commercial poultry. Efforts should also be made on the discovery of novel antigens for incorporation into vaccine designs which might be more effective against multiple Eimeria species. This review presents a recap to the overall progress against chicken Eimeria with particular reference to previous decade. The article presents critical analysis of potential areas for future research in chicken Eimeria vaccine development.

Keywords: Antigens; Control; Eimeria; Poultry; Vaccine.

Fig. 1

Cell-mediated immunity due to Eimeria infection/vaccination. Cellular immune response priming takes place when Eimeria is taken to antigen-presenting cells. Antigenic proteins from Eimeria parasite are converted into peptides that bind with the cytokine primed cytotoxic T cells. These cytotoxic T cells either get activated and start inoculating the cells for death or may lead to formation of memory T cells

Fig. 2

CD4/T-helper immunity in Eimeriosis. Humoral immune response priming takes place when Eimeria is taken to antigen-presenting cells. Antigenic proteins from Eimeria parasite are converted into peptides that bind with the cytokine primed helper T cells. The cytokine release help in B cell activation and release of antibodies or they may form memory cells for future immunological response on Eimeria challenge

Fig. 3

Eimeria vaccines: summary of preparation and application. The genes from target antigen are amplified, introduced to the plasmid. Insertion and bacterial transformation take place. The transgenic plasmid is purified to form a vaccine. Chickens are immunized with the dose of vaccine. Immunological interactions take place within host body and provide immune protection in the face of disease