Controlling the causative agents of coccidiosis in domestic chickens; an eye on the past and considerations for the future

Abstract

Coccidiosis is a potentially severe enteritis caused by species of obligate intracellular parasites of the genus Eimeria. These parasites cause significant economic losses to the poultry industry, predominantly due to compromised efficiency of production as well as the cost of control. These losses were recently estimated to cost chicken producers approximately £10.4 billion worldwide annually. High levels of Eimeria infection cause clinical coccidiosis which is a significant threat to poultry welfare, and a pre-disposing contributory factor for necrotic enteritis. Control of Eimeria parasites and coccidiosis is therefore an important endeavour; multiple approaches have been developed and these are often deployed together. This review summarises current trends in strategies for control of Eimeria, focusing on three main areas: good husbandry, chemoprophylaxis and vaccination. There is currently no “perfect solution” and there are advantages and limitations to all existing methods. Therefore, the aim of this review is to present current control strategies and suggest how these may develop in the future.

Identification and Protective Efficacy of Eimeria tenella Rhoptry Kinase Family Protein 17

“…Annual global economic losses due to coccidiosis are estimated to be USD 3 billion [ 4 ]. Conventional strategies used to control the disease depend heavily on chemoprophylaxis [ 5 , 6 ]. Meanwhile, live anticoccidial vaccines are used commercially for the control of avian coccidiosis [ 6 ].…”

“…Conventional strategies used to control the disease depend heavily on chemoprophylaxis [ 5 , 6 ]. Meanwhile, live anticoccidial vaccines are used commercially for the control of avian coccidiosis [ 6 ]. However, the use of live anticoccidial vaccines or anti-parasitic drugs has disadvantages, such as the occurrence of drug resistance, complex production processes, and potential pathogenicity [ 7 , 8 ].…”

Nutritional interventions to support broiler chickens during Eimeria infection

“…The widespread increase in occurrence of anticoccidial drug resistance and societal pressure to reduce the use of antimicrobials from a public health perspective ( Agunos et al, 2017 ) has increased the search for alternatives, such as vaccination, botanicals, organic acids, immunomodulators, carbohydrates, probiotics, and prebiotics ( Blake et al, 2021 ). In Europe, in contrast to the USA, the use of live anticoccidial vaccines, especially in broilers, has remained limited for four reasons: (1) Only attenuated anticoccidial vaccines are approved and their cost of production is significantly higher than that of nonattenuated vaccines, (2) The use of anticoccidials belonging to the polyether ionophore class is permitted in antibiotic-free production systems, (3) Consistent application may be challenging for farmers, and (4) Slower development of immunity than with non-attenuated anticoccidial vaccines ( Blake and Tomley, 2014 ; Noack et al, 2019 ; Blake et al, 2020 ; Attree et al, 2021 ). Nevertheless, programs where live vaccines are alternated between production cycles with anticoccidials are increasingly being applied to restore sensitivity to anticoccidials ( Kadykalo et al, 2018 ; Blake et al, 2021 ).…”

Biocontrol of Avian Gastrointestinal Parasites Using Predatory Fungi: Current Status, Challenges, and Opportunities

“…Domestic and exotic birds are commonly exposed to a wide variety of generalist or host-specific gastrointestinal (GI) parasites, with different life cycles and levels of pathogenicity [1][2][3][4][5][6][7][8].…”

“…and Isospora spp. can reach prevalence and shedding values up to 80% and 15,000 oocysts per gram of feces (OPG), respectively [6,[9][10][11][12][13][14] and are currently responsible for average losses of approximately 12 billion € annually worldwide in the poultry industry [5,15]. Nematode infections are also a serious problem in Galliformes, being ascarids (e.g., Ascaridia galli), heterakids (e.g., Heterakis gallinarum and H. isolonche), capillarids (e.g., Capillaria spp.…”