I’ve been working a little bit on a little side project, which I’ve known about for years but kept putting in the bottom drawer of my research life: swamp fever.
What, Merle, is swamp fever?
It’s equine infectious anemia, and let me say right from the outset, that it remains a terrible killer of horses. The Merck manual, that guide for all veterinarians, notes that it is a non-contagious virus. And it can kill a horse, either quickly or very slowly.
Others have likened EIA, or swamp fever, to a horse-form of AIDS. In fact, some researchers have pointed to the work done to find a vaccine for swamp fever as holding out some possibilities for AIDS researchers.
So, it’s viral, and non-contagious. Except when spread by blood. In this case, EIA is spread by the bite of a fly. Any biting fly. So, EIA is found more readily in places where there may be a lot of biting flies.
Like a swamp. Or a low-lying swampy region, filled with luscious grass and abundant water. The bottom of a pasture. Or, the edge of a forest.
In western Canada, swamp fever rose to critical prominence as agriculture grew. First noted with alarm in the 1880s, it was a disease of the edge, of the new homesteads created in the bushy places, where water is abundant. It was not, nor is it now, a disease much found or noted on the open, dry plain.
Symptoms were distressing but distressingly difficult to pinpoint. A high fever. Or a small one. Or one that bounced around. Lethargy and extreme tiredness. Flesh wasting away while an animal gorged itself, eating itself to starvation. A change in personality. Depression, in an otherwise happy, playful, even spiteful animal.
How do you tell the vet: my horse is depressed? How do you tell an early 20th Century vet: my horse is depressed? It’s a symptom that hadn’t really been invented yet. It wasn’t an available condition.
Results could be quickly lethal, or distressingly chronic. A horse could seem to recover, but with any work, could relapse. Another horse could sicken and die within days, leaving a farm with limited horsepower. In a busy season, swamp fever was a disaster. For a small farm with few resources and little money, it could be the straw that breaks the farm’s back.
But here’s the real problem: another horse can look completely healthy, but be carrier. Those are, in fact, the most problematic. Because in order for an outbreak of swamp fever to occur, there must be a carrier present. There must be a sick horse nearby, for the biting flies to feast upon, to spread the disease. The obviously sick ones can be quarantined. The healthy carriers, with no obvious symptoms, are the deadliest.
There has been well over 100 years of research on EIA, across multiple continents, with no cure and no vaccine. It remains a world-wide scourge of horses, donkeys, and mules.
Horses — and farms — which catch swamp fever go under immediate quarantine, for life, or face euthanasia. It puts a huge burden on farms to keep an infected animal alive, for limited purpose. Yet, the human-animal bond can be strong, and some farmers are willing to isolate and keep their horse, using all necessary precaution, to help it live a decent life.
A rural farm 100 years ago usually didn’t have that luxury.