The influence of parasitic infection (Eimeria spp.) on bone and cartilage tissue in an animal model.

Intestinal parasitism impact on skeletal development is poorly characterised. This study examined whether infection with Eimeria spp. disrupts bone and cartilage homeostasis in rapidly growing broiler chickens. Male Ross 308 chicks were randomly assigned to control or infection groups. On day 20 post-hatch, infected birds received a mixed oral inoculum of Eimeria spp.; controls were sham-dosed and euthanised 22 days later. Tibial osteometry, densitometry, strength, mineral composition and histomorphometry were assessed. Serum markers of bone turnover and inflammation were measured. Infection reduced maximum elastic strength, ultimate strength and elastic energy of the tibia. Trabecular bone volume fraction and thickness declined, whereas trabecular separation increased. The proportion of thin collagen in trabecular, cortical and articular tissues was reduced. Articular cartilage exhibited thinning of the superficial and deep zones and diminished proteoglycan staining. Mineral analysis revealed a lower Ca:P ratio and elevated copper and sulfur content. Serum IGF-1 decreased, while osteoprotegerin, IL-1β, IL-6, IgY, IgM and ceruloplasmin increased. These results demonstrate that Eimeria infection can secondarily compromise skeletal development through inflammatory and metabolic pathways. The broiler model therefore offers a tractable platform for investigating infection-associated, inflammation-driven bone loss relevant to paediatric and post-infectious osteopathies.