A University of Saskatchewan (USask) research team has created an aerosol vaccine that protects poultry from necrotic enteritis, a bacterial disease caused by Clostridium perfringens type G. This disease leads to a 50% fatality rate among affected chickens and can cause food poisoning in humans who consume contaminated, undercooked chicken meat.
“This disease is re-emerging due to reduced antibiotic use in the poultry industry,” says Dr. Hemlata Gautam, a PhD candidate in the Department of Veterinary Pathology at the Western College of Veterinary Medicine (WCVM).
Under the supervision of Dr. Susantha Gomis, a WCVM professor and poultry specialist, Gautam is exploring alternative strategies to control and prevent necrotic enteritis without relying on antibiotics. The Canadian poultry industry is phasing out prophylactic antibiotics in broiler chicken production to combat antimicrobial resistance.
“Currently, there is no effective control for this disease, so scientists are working on preventive strategies. Our research has developed a vaccination strategy to prevent it,” Gautam explains.
Gautam’s research emphasizes timing. Chickens’ immune systems are vulnerable due to their young age, and maternal antibodies only protect them for a few weeks post-hatching. “We need to strengthen chickens’ immunity by their third week of life,” she notes.
The WCVM team starts protection even before the chicks hatch. In Gautam’s study, synthetic DNA was injected into chicken eggs three days before hatching, activating the embryos’ immune systems. This process stimulates the lungs to recognize bacteria faster and produce an immune response in the gut.
“We used the concept of mucosal vaccination through the chick’s lung mucosa, leveraging the gut-lung axis to deliver the vaccine,” says Gautam.
Newly hatched chicks were placed in a nebulizer chamber to receive a single dose of a live aerosol vaccine through the lungs, simplifying the vaccination process.
At three weeks old, the vaccinated chicks were exposed to Clostridium perfringens for three days. While unvaccinated chicks typically develop severe intestinal damage, vaccinated chicks remained healthy, proving the vaccine’s effectiveness.
“By administering a single lung-based vaccine dose, we can protect chicks against necrotic enteritis,” Gautam states.
However, Gautam emphasizes that this vaccine has only been tested in experimental settings. “To fully understand its effectiveness in real-world conditions, field trials are necessary.”
In addition to the necrotic enteritis vaccine, Gomis’s team is improving diagnostic tests by analyzing molecules in chicken feces. This research may eventually allow for blood sample testing to diagnose necrotic enteritis and other diseases.
Gautam believes that similar vaccination strategies could combat other poultry diseases and might even extend to humans and other animals. “Administering vaccines through the lungs is a growing field. This approach could protect different intestinal areas and other species, benefiting the poultry industry and beyond.”
The project is funded by the Canadian Poultry Research Council, Agriculture and Agri-Food Canada, and the Chicken Farmers of Saskatchewan.
