Highly Pathogenic Avian Influenza

Winter 2025: Bird flu of various types has been circulating for a pretty long time, but this round could be a little bit different. Why are some influenzas a big deal while others are (apparently) not?

First off, you never want to underestimate any variety of flu. I cringe when I hear people use language like “just the flu” or “common flu”. The flu may be around all the time, but it is far from a trivial matter. Influenza is responsible for hospitalizing about 200,000 Americans each year and snuffs out an average of 36,000 American lives per year. The severity of “flu season” varies, but it never stops killing. That’s because the virus itself is continuously evolving and improving its tactics for survival and reproduction, a goal which brings damage and death to everything in its path. Even the strongest immune systems can’t keep up with this enemy.

Influenza viruses are all part of a massive family in which each member is able to mutate independently but also to swap information with any other member of the family. The reproduction of its genetic material is highly prone to proofreading errors, and evolution is built on errors. Each and every error is a brand-new chance to get the upper hand. In addition, one of its favorite pastimes is meeting new viruses. When two influenzas meet, the sparks really fly, because mutating with a buddy has far more destructive potential than mutating alone. Bird flu (an Influenza A) is a very rapid mutator and infects a huge variety of birds and mammals, which means lots and lots of chances to party with other viruses. It’s been estimated that Influenza A can evolve one million times faster than a mammal, so fast that the human flu vaccine has to be reformulated every single year.

How does this affect you, a human being and pet owner? It’s actually pretty difficult to catch a bird flu infection yourself, unless you work in a barn with infected poultry or cows. The vulnerable spot in some of your households is the family cat, which can become fatally ill with HPAI without ever setting foot outdoors. How? Most human beings are cautious, even meticulous, about their own contact with raw meat and untreated milk, but some of us haven’t checked our blind spot, the family pet. If you’re bringing raw pet food or untreated milk into your home, you’re inviting disaster for your cat. Multiple feline infections have been definitively traced to raw and unpasteurized pet food. Cooked chicken and pasteurized milk are not a source of bird flu.

Indoor/outdoor pets should also be isolated from wild birds and poultry (alive or dead) where possible. This may mean reconsidering that backyard bird feeder and perhaps even intentionally discouraging wild birds from lingering on your property. Dogs are currently less vulnerable to infection than cats; however, it is still possible for them to become infected (and die) from contact with wild bird carcasses.

It’s not time to go into panic mode over HPAI, but you’ll want to keep your eye on the news; the situation is changing on a weekly to daily basis. I highly recommend eliminating contact (direct or indirect) between indoor pets and outdoor birds, as well as keeping raw meat/milk out of their diet.

Dr M.S. Regan