What Screwworm Reminds Us About Animal Welfare

By Lisa

Every so often a story comes along that reminds us just how connected animal health has become. A parasite that most North Americans haven't had to think about for decades has reappeared in the United States. While it's not a reason to panic, it is a reason to pay attention.

The parasite is called New World screwworm. Despite its name, it isn't actually a worm. It is the larval stage of a fly that lays eggs in open wounds. When the eggs hatch, the larvae feed on living tissue, causing severe injuries to livestock, wildlife, pets, and, in rare cases, people. Unlike many maggots that feed on dead tissue, screwworm larvae feed on living flesh. In simple terms, they make a wound larger instead of allowing it to heal. Left untreated, infestations can cause extensive tissue damage, severe suffering, secondary infections, and, in some cases, death. That is why even a small number of cases receives immediate attention from veterinary and agricultural authorities.

The good news is that New World screwworm is not present in Canada. Canada's climate remains one of our best defenses, as screwworm thrives in hot, humid environments and is not well suited to our long winters. That doesn't mean we ignore the risk. Southern Ontario and other warmer regions can experience summer conditions that may allow temporary survival if an infected animal were introduced. This is why surveillance, veterinary screening, and import controls remain important even in countries where the parasite is not currently present.

For those of us in Ontario cottage country, this is not something that should keep us awake at night. Most dogs travelling with their families are well cared for and receive regular veterinary care. Responsible owners tend to notice problems early and seek treatment when needed.

What this story does highlight is how much animal movement has changed over the years. I've been around dogs long enough to know that dogs crossing borders is nothing new. Show dogs, breeding dogs, and working dogs have travelled internationally for generations to strengthen breeding programs, support working and sporting dogs, and preserve breeds for the future. Those movements have traditionally involved health testing, documentation, and oversight every step of the way.

What has changed is the number of dogs now moving through rescue transport networks and the complexity of the journey from one caregiver to the next. Many of these efforts are driven by genuine compassion and a desire to help dogs in difficult situations. But moving animals across long distances always carries responsibility. Disease outbreaks like screwworm are a reminder that good intentions must be supported by sound veterinary screening, documentation, and accountability at every step of the journey. Animal health officials don't impose surveillance zones, movement controls, and import restrictions because they doubt people's intentions. They do it because even a single case can have far-reaching consequences for livestock, pets, wildlife, and the people who care for them.

Many communities are already struggling with veterinary shortages, limited access to care, and shelters operating under constant pressure. These challenges are connected. Animal welfare is about much more than moving dogs from one location to another. It is about creating systems that support healthy animals, informed owners, responsible breeding practices, and sustainable care.

These realities also raise a broader question. When veterinary resources, qualified homes, and shelter capacity are already under pressure, how should we balance helping dogs abroad with meeting the needs of dogs already here in Canada?

There may not be a single right answer. But long-term animal welfare is about more than transportation. It is also about education, responsible ownership, access to veterinary care, effective breeding practices, and helping communities build sustainable animal welfare systems of their own.

For now, Canada remains screwworm-free, and there is no immediate reason for concern among local pet owners. But the reappearance of this parasite is a useful reminder that protecting animal health requires vigilance, cooperation, and a willingness to think beyond our own backyard.

After spending most of my life around dogs, one thing I have learned is that animal health is never somebody else's problem. Good intentions matter, but they are not a substitute for knowledge, experience, and responsibility. Whether we are talking about breeding, rescue, ownership, or animal health, dogs depend on us to make informed decisions on their behalf. They don't get a vote. The responsibility is ours.

That, to me, is the difference between caring about animals and providing effective animal welfare.