Bacterial chondronecrosis with osteomyelitis ('femoral head necrosis') of broiler chickens: A review

Abstract

Bacterial chondronecrosis with osteomyelitis (BCO) in chickens was first reported in 1972 and is now recognized as an important cause of lameness in broiler chickens. Recent systematic studies of causes of lameness in birds reared in Northern Ireland have shown that it was the most common cause of lameness, being present in 17.3% of lame birds. Furthermore, it was also detected in birds presented as "found dead". Overall losses in male birds due to BCO were estimated to be 0.75% of all birds placed, which, in addition to welfare concerns, represents considerable economic loss. The disease has been seen in birds ranging from 14 to 70 days of age, but most cases occurred around 35 days old. It is most commonly caused by Staphylococcus aureus, but Escherichia coli, coagulase-negativ e staphylococci and Enterococcus spp. are sometimes involved, as are, rarely, other bacteria. The lesions are most commonly found associated with the growth plates of long bones, particularly the proximal growth plate of the femur and tibiotarsus, but other bones may also be affected. Since lesions were visible to the naked eye in only 40 to 67% of cases, histological examination is recommended where no lesions are visible macroscopically. As the lesion may be present in only one growth plate, and because histological examination is often not carried out, BCO is almost certainly underdiagnosed. The exact pathogenesis of the condition is unknown, but it is thought that adherence of blood-borne bacteria to exposed cartilage at the tips of metaphyseal blood vessels is fundamental. Under controlled experimental conditions, infection of birds with the immunosuppressive viruses chicken anaemia virus and infectious bursal disease virus increased the incidence of the disease, while restricting feed intake reduced the incidence of disease. S. aureus strains identical to, or closely related to, isolates recovered from naturally occurring cases of the disease (as determined by pulsed-field gel electrophoresis) have been recovered from fluff-debris in hatcheries, and also from the environment of breeding flocks, indicating that infection in the breeding farm and in the hatchery could be an important source of infection. It has also been shown that humans can carry poultry strains of S. aureus on their hands. There is a higher incidence of BCO in birds hatched from floor eggs. Thus, hygiene and management practice on breeder farms and in the hatchery may influence the occurrence of the disease. Bacteraemia is a prerequisite for BCO. Indeed, in some flocks suffering losses due to BCO, there are also losses due to staphylococcal septicaemia. Thus, appropriate treatment of affected flocks should reduce losses due to septicaemia. It should also reduce the occurrence of bacteraemia and the development of further cases of BCO. However, birds in which BCO has already developed, are unlikely to respond to treatment. Control of BCO by vaccination seems unlikely in the short term. Simple bacterins have not been effective and much basic research is needed to i...

Evaluating portable wire-flooring models for inducing bacterial chondronecrosis with osteomyelitis in broilers

“…Previously published photographs illustrate typical BCO lesions of the proximal femora and tibiae Wideman and Prisby, 2013). Proximal femoral head lesions (FHS, FHT, FHN) and tibial head lesions (THN, THNs, THNc) were categorized separately to emphasize the progressive development of BCO in the proximal ends of both long bones of the legs (Mutalib et al, 1983a;Thorp and Waddington, 1997;McNamee et al, 1998McNamee et al, , 1999Butterworth, 1999;McNamee and Smyth, 2000;Dinev, 2009;Durairaj et al, 2009;. Proximal femora and tibiae that appeared to be normal macroscopically were not routinely evaluated microscopically.…”

“…In advanced stages, birds are fully immobilized, resulting in their inability to reach feed or water. Most cases of BCO develop after 35 d of age (Nairn and Watson, 1972;McNamee et al, 1999;McNamee and Smyth, 2000;.…”

“…Broilers raised on wire flooring also experience physiological stress leading to increased serum levels of corticosterone and elevated heterophil-to-lymphocyte ratios that are associated with lack of access to floor litter (El-Lethey et al, 2003;Wideman and Prisby, 2013). Stress-induced immunosuppression and bacterial translocation contribute to the focal bacterial proliferation associated with spontaneous BCO outbreaks in commercial broiler flocks (Mutalib et al, 1983a;Butterworth, 1999;McNamee and Smyth, 2000;Wideman and Prisby, 2013).…”

Performance, Livability, and Carcass Yield of Slow- and Fast-Growing Chicken Genotypes Fed Low-Nutrient or Standard Diets and Raised Indoors or with Outdoor Access

“…Although their causes are complex and multifactorial, fast growth is certainly a contributing factor (Mench, 2004). Slower-growing birds have a lower incidence of bacterial chondronecrosis (McNamee and Smythe, 2000), and slowing growth in the first 15 to 20 d of life can reduce incidence of angular bone deformity and dyschondroplasia (Classen and Riddell, 1989). Slowgrowing genotypes are reported to have less varus-valgus deformity than fast-growing genotypes (Leterrier et al, 1998).…”

Detection of Staphylococcus Aureus Among Coagulase Positive Staphylococci from Animal Origin Based on Conventional and Molecular Methods

“…S. aureus is also an important pathogen in veterinary medicine. It has been reported as etiological agent of various infections in cattle, especially mastitis (10), in horses (11), dogs (12), cats (13), rabbits (14), poultry (15) and reptiles (16). Schaumburg et al (17) and Monecke et al (18) have also isolated S. aureus from non-human primates in Africa and from diseased hedgehogs in Sweden, respectively.…”