Enterococcal-related vertebral osteoarthritis in South African broiler breeders: A case report

Abstract

Infections in broilers and broiler breeders by Enterococcus cecorum, causing clinical disease, have increasingly been described in various countries in the Northern Hemisphere over the past decade. This case report describes an outbreak of enterococcal-associated vertebral osteoarthritis (EVOA) in male broiler breeders in several flocks in South Africa. Male birds aged 4 and 9 weeks displayed the common presentation of lameness, paresis or complete paralysis. Autopsies of culled birds revealed masses on caudal thoracic vertebrae T5-T7, with vertebral osteomyelitis and spondylitis. Microbiological assays identified E. cecorum cultured from spondylitic lesions. Affected flocks were treated with amoxycillin at 25 mg/kg in the drinking water for 5 days, resulting in decreased numbers of lame birds and culls. The origin and pathogenesis of EVOA are poorly understood, which limits prevention to environmental factors that may inhibit systemic access by the enteric bacteria. Skeletal growth trends of male birds are thought to increase their susceptibility to bacterial colonisation at sites of skeletal strain, resulting in abscesses and lesions. Evidence points to the emergence of E. cecorum strains with increased pathogenicity; this highlights the need for greater understanding of the origins, treatment and prevention of EVOA to minimise its economic impact on poultry operations.

Pathogenesis of Enterococcal Spondylitis Caused by Enterococcus cecorum in Broiler Chickens

“…This observation is in contrast to the clinical case reports in which there has been a predisposition of male birds to ES. [1][2][3]12 The ES was first described, and continues to be reported, in male broiler breeders providing further support for this association. It may be that the association of sex with ES is a weak one, which requires the numbers present in commercial operations to be identified.…”

“…23,24 The most common and recognizable clinical disease caused by pathogenic E. cecorum occurs in broiler chickens and is called enterococcal spondylitis (ES; also known as vertebral osteoarthritis [VOA] or ''kinky back''). [1][2][3]6,8,12,13,21,25,27,35,36,39 Unfortunately, one of the most frequently utilized common names for ES, kinky back, also refers to a developmental disease of chickens with a genetic basis, in which a malformation of the spinal column (spondylolisthesis) results in compression of the spinal cord and clinical signs that overlap with ES. 13,39 Outbreaks of ES have a typical presentation where symmetrical hind limb paraparesis or paralysis develops in affected birds at 5-8 weeks of age and results in 5%-15% mortality.…”

Vertebral Osteomyelitis in Broilers: A Review

“…VO has been reported in poultry in different European countries, such as the United Kingdon (Wood et al, 2002), The Netherlands (Devriese et al, 2002;Kense & Landman, 2011), Belgium (Herdt et al, 2009), Hungary (Makrai et al, 2011), Norway (Kolbjørnsen et al, 2011), and Bulgaria (Dinev, 2013). The disease was also described in South Africa (Aitchison et al, 2014), Iran (Talebi et al, 2016) and some Vertebral Osteomyelitis in Broilers: A Review countries in North and South America, such as Canada (Stalker et al, 2010), several US states (Pennsylvania, Washington, North Carolina, South Carolina, Arkansas, Mississippi, Alabama, and California) (Aziz & Barnes, 2009;Gingerich, 2009), and Brazil (Braga et al, 2016b).…”

“…According to some reports, the disease occurs more frequently in males (Aziz & Barnes, 2007;Herdt et al, 2009;Aitchison et al, 2014) and may affect several strains (Wood et al, 2002;Gingerich, 2009). The higher body weight normally observed in males ( Figure 1) implies an increase in the weight needed to be supported by bones and joints and a greater possibility of trauma.…”

“…Since 2002, E. cecorum has been found to be the bacterium most often involved in outbreaks of non-Vertebral Osteomyelitis in Broilers: A Review vertebral and vertebral osteomyelitis and arthritis in broiler and broiler breeders (Aziz & Barnes, 2007;Herdt et al, 2009;Aziz & Barnes, 2009;Gingerich, 2009;Stalker et al, 2010;Martin et al, 2011;Boerlin et al, 2012;Aitchison et al, 2014).…”