Avian coccidiosis as a prototype intestinal disease: Recent advances in host protective immunity and novel disease control strategies

Authors: Lillehoj, Hyun; JANG, SEUNG - US Department Of Agriculture (USDA); Lee, Sung; LILLEHOJ, ERIK - University Of Maryland

Submitted to: Intestinal Health: Key to optimise production
Publication Type: Book / Chapter
Publication Acceptance Date: 2/1/2015
Publication Date: 4/1/2015
Citation: Lillehoj, H.S., Jang, S.I., Lee, S.H., Lillehoj, E.P. 2015. Avian coccidiosis as a prototype intestinal disease: Recent advances in host protective immunity and novel disease control strategies. Intestinal Health: Key to optimise production. p. 71-116.

Interpretive Summary: Intestinal parasites of the Eimeria family cause the disease coccidiosis, evident by a destruction of the gut’s integrity and poor nutrient absorption. The additition of drugs against coccidiosis and “growth promoter” antibiotics to poultry feed have traditionally proven highly effective in mitigating the reduction in body weight gain associated with coccidiosis in birds, including poultry. More recently, however, there has been an increase in the number of antibiotic-free poultry flocks as a consequence of the governmental and social regulation of drug usage in animal production. In this paper, ARS scientists and collaborators reviewed the current knowledge on improving gut health by reducing losses due to intestinal pathogens, especially parasites. This review shows the progress made in understanding biological mechanisms present within cells that are associated with intestinal parasitism and the significant contribution of various scientific disciplines, genomics, immunology and molecular biology, in understanding the complex host pathogen inter-relationship. This information will help scientists in industry and academia develop logical management strategies against coccidiosis in birds.

Technical Abstract: Poultry meat consumption has increased globally by 50% since 2000, accounting for greater than 100 million tons in 2012. Multiple challenges confront the rising demand for poultry food products, including governmental restrictions on the use of antibiotic growth promoters and novel feedstuffs, high-density production conditions, waste management, and the emergence of infectious pathogens, particularly those that cause intestinal diseases. There is little doubt that in-feed antibiotics have dramatically increased the efficiency of commercial poultry production over the last 50 years. However, antibiotic usage in chickens has raised consumer concerns regarding chemical residues in the poultry products that they consume, and has directly led to the appearance of drug resistance among avian pathogens that has the potential to be transferred to microorganisms that infect humans. Much interest, therefore, has focused on the development of alternative, antibiotic-free methods of commercial poultry production. These newer disease control strategies can be broadly classified into those that are directly cytotoxic against infectious agents, including hyperimmune antibodies, antimicrobial peptides, and bacteriophages, and those that augment host immunity, including phytochemicals, adjuvants, and next-generation vaccines. Additionally, the identification of new chicken genetic markers opens the door for the development of novel chicken breeds with increased resistance to infectious diseases through gene modification and DNA-based selection strategies. This chapter addresses alternatives to antibiotics in the context of avian coccidiosis, a prototypical intestinal disease of chickens. First, the biology of Eimeria, the causative agent of coccidiosis, is briefly reviewed, followed by a summary of the chicken immune response to Eimeria infection, and finally an appraisal of recent advances in nontraditional coccidiosis control strategies.