E. cecorum: Old foe, new challenge

The Canadian poultry industry is no stranger to Enterococcus cecorum (E. cecorum). Pathogenic strains of the bacteria have been identified in chickens in various countries, including Canada since 2002, mainly resulting in lameness and bone lesions. 

More recent poultry outbreaks, however, have shown up as septicaemic at a much earlier age and are proving much harder to address. 

Presenters during a recent Broiler School webinar series hosted by Canadian Poultry all identified E. cecorum as an emerging threat to chickens. And at the 2023 Poultry Industry Services Workshop, Ontario veterinarian Dr. Jess Walkey spoke about the changing nature of the bacteria and the problems it’s causing for poultry producers. 

“From my Ontario perspective, I would say that although it isn’t new, Enterococcus is becoming a tricky one to solve. It’s a bacterial condition that seems to create many challenges and its prevalence in Ontario is on an upward trend,” Walkey says. 

This is backed up by the regular health summaries released by the Ontario Animal Health Network (OAHN) every three months: for the past year or so, both E. cecorum and E. coli have been the top two bacteria isolated from poultry. 

Bone lesions and lameness
E. cecorum had long been considered as what is called commensal bacteria in avian species – present but not causing negative health impacts. However, that changed over 20 years ago, when pathogenic strains of the bacteria were first identified in chickens. 

Outbreaks happened first in the UK and the Netherlands, followed by other countries like Canada, the United States and South Africa. These pathogenic strains changed the impact of E. cecorum on the health of broilers and broiler breeders, causing primarily bone lesions and lameness. 

“We started seeing a problem like kinky back in older broilers that eventually paralyzes the bird,” explains veterinarian Dr. Benoit Lanthier, Technical Services Representative at Cobb-Vantress, adding this would result in dehydration, starvation and in welfare-related culling or birds deemed unfit to ship. 

“Lameness was the biggest symptom of E. cecorum: birds limping or sitting on their hocks with legs stretched out,” adds Dr. Emily Martin from the Animal Health Laboratory at the University of Guelph. “There are multiple places the bacteria locate, but one area in the spinal column that it locates in is a moveable vertebra in the back, where it causes an abscess, putting pressure on the spinal cord and causing lameness.”

Different symptoms, younger birds
At some point over the last several years, the situation began to change, however. According to Martin, poultry pathologists and bacteriologists were starting to see different presentations, including septicemia conditions in two- to three-week-old birds. 

“As our technology improves, we have better abilities to detect different types of bacteria and how they evolve. Bacteria are like any other living thing, they have their family trees, and we look at their genetic structure,” she says. “What was probably happening in earlier lameness cases is that the birds were septicaemic, but it wasn’t a huge problem in flocks causing sick birds and mortality.” 

Experts believe the E. cecorum strains have evolved again, with different strains now causing the bacterial septicemia with symptoms similar to those from an E. coli infection. 

Birds as young as 10 days of age are now being affected, with symptoms including pericarditis (an inflammation of the lining of the heart), a yellowish membrane over the surface of the liver and abscesses in long bones like the tibia. Birds that survive the initial infection will most likely develop lameness problems as they get older. 

Producers will most likely first see sick birds with uniformity issues, reduced daily gain, increased mortality and culls, and potentially an increase in condemnations at the plant. 

“Any birds with any type of bacterial infection, like E. cecorum or E. coli or a mix, will be inactive, fluffed up and depressed with their eyes closed so you know they’re sick,” Martin says. “We have to send tissue to have them culture it (for diagnosis), but we often see E. cecorum in combination with E. coli.” 

Minimizing risk
According to both Martin and Lanthier, once E. cecorum infection is present on-farm, it tends to reoccur and can be difficult to eradicate. It’s an organism that is more likely to survive longer in the litter, for example, as well as in cold and dry environments than other pathogens. 

“It’s pretty much everywhere in Canada and the U.S. and everybody will struggle with it at some point,” Lanthier notes. “Once one flock is hit, then it’s every flock.” 

Maintaining a healthy barn environment is important, with a strong focus on cleaning and disinfection between flocks, particularly of waterlines, and keeping some downtime after birds go out. 

Biosecurity is also key to keep other immunosuppressive viruses at bay. Watch birds closely once they’re placed and consult with your flock veterinarian on how to treat sick birds and reduce their symptoms. 

Conditions at hatch
Experts suspect that this latest evolution of E. cecorum bacteria could be linked to hatcheries halting the preventative use of antibiotics to keep newly hatched chicks healthy. This has caused a need for greater attention to detail and environmental control during and right after hatch. 

Lanthier has seen some of his customers experience success in hatching chicks in HatchCare incubators. The HatchCare system gives chicks the best and most uniform temperature conditions and light, feed, and water as soon as they hatch, as well as a quieter, calmer environment with more space to move around. It also allows for excellent biosecurity and hygiene control. 

“When hatching with HatchCare, we don’t see the problem in the flock or only see it very mild,” Lanthier says. “The management piece is important, having those good conditions early on with access to feed and water right away. If it’s done well, the chicks hatch and do well right away.” 

It can be hard to control all the variables in more traditional systems, especially keeping chicks from getting overheated, which has been linked to higher levels of E. cecorum, and preventing them from being exposed to bacteria. 

Research is ongoing to get a better understanding of both how the organism behaves and what can be done to effectively prevent or minimize its risk. 

A timely webinar
As part of our ongoing webinar series on disease threats to poultry this month, Dr. Benoit Lanthier of Cobb-Vantress will look at E. cecorum and the evolving challenges it presents. Register Today!