Editorial – June 2002
By Marilyn White
By Marilyn White
Four million commercial birds have been destroyed and the numbers continue to climb as new cases are diagnosed daily. Barns are being thoroughly cleaned of their built-up litter and everything is being disinfected. Farm personnel are being detained, sometimes for days until quarantines can be lifted. All in an attempt to control the spread of the disease – Avian Influenza (AI) has hit the northeastern U.S. after a respite of nearly 20 years.
Virginia has been trying to control the disease, without success, since March 12. Even now, no one knows how it started but migratory waterfowl are the likely suspects. Wild birds can act as reservoirs for the virus without showing any signs themselves but pass it on to more sensitive domestic poultry. One gram of fecal material from an infected wild bird can contain enough AI virus to infect one million birds. Officials have been unable to determine how the disease is being spread, making it difficult to break the cycle of infection and bring the disease under control. And it is continuing – on May 10, it showed up in the more northern state of West Virginia, where nearly 13,000 chicken breeders had to be destroyed. A state of emergency was quickly declared in an attempt to contain the disease.
This particular AI is not killing the birds – people are. This disease has the potential to get much worse and it has everyone reacting. It’s a low pathogenic form of AI (LPAI) that is neither fatal to chickens and turkeys nor does it cause any problems in humans. It causes a number of production-decreasing symptoms including soft-shelled eggs and decreased hatchability. The problem is that this LPAI has the ability to mutate or change into a highly pathogenic (HPAI) form and do it fairly quickly, resulting in a much more dangerous disease. This happened in 1983/4 in the northeastern U.S. and resulted in the destruction of 17 million birds at a cost of almost $70 million. It happened more recently in Hong Kong in 1997 where it took an additional twist and, for the first (and only) time, jumped to humans infecting 18 of whom six died. With this, the stakes got higher. Hence the industry and government concern over LPAI and its eradication.
The U.S. has been expecting AI to strike again and has been preparing for such an occurrence. Even so, the disease continues to spread and the longer it remains uncontrolled, the greater the risk of it becoming an HPAI.
Canada must pay close attention to what is happening is the U.S. CFIA is monitoring the U.S. situation on a daily basis and continues with a “wait and see” position. As long as it remains an LPAI or unless the U.S. federal government declares an emergency, its policy won’t change. Canada closed the borders to U.S. imports in 1983/4 with the outbreak of HPAI but does not place any restrictions for an LPAI. No additional preventative measures are in place at our borders even though AI can be carried on footwear and clothing and by vehicular traffic. Some hatcheries are taking extra preventative measures by testing incoming U.S. breeder chicks for AI antigens.
With shrinking government support staff and diagnostic lab closures, I think the Canadian farmer and the veterinarians will be key in reducing the risk of an AI outbreak. The same migratory pathway for waterfowl that comes up through Virginia/West Virginia also extends over Ontario en route to the Canadian north. Birds, in transit, could leave AI virus behind in their fecals. The virus is well protected by organic matter and can survive in manure for up to 105 days. On-farm biosecurity becomes very important in preventing wild birds, trucks and people from inadvertently bringing it onto the farm. Farmers should talk to their poultry veterinarian and know what to do if they suspect AI.
As the bird flies, the area involved in the U.S. is a mere 500 miles – a one-day drive from one of Ontario’s most densely populated poultry areas. Whether it’s spreading by waterfowl, people, wind, etc., the virus is jumping state lines and causing huge economic losses in the U.S. We need to be prepared to minimize the effects should it come here. While Canadians might like to make distinctions between states and provinces, AI doesn’t.