This letter is in response to the letter written by Brenda Collier that was published in the Penticton Western News on Sept. 30. These are facts that are available for anyone to look up on the Internet, facts that will make your skin crawl. Look it up for yourself, especially those of you who are sitting on council and do not think this is something you should be concerned about or wish to take into serious consideration. If this was in your neighbourhood or your garden, it was a threat to you and your family at this very moment as it is for us here only one block from Penticton City Hall.
Now here is a roundworm you do not hear that much about, and hopefully you will never meet. But if you do, it is serious. Baylisascaris procyonis is a roundworm of raccoons. It does not cause severe disease in raccoons except in the young who may develop intestinal obstructions. The real hazard is when it infects humans or dogs. In man, it causes a condition called neural larva migrans, or cerebrospinal nematodiasis. This is a rare disease, but is serious and often fatal.
Besides dogs and humans, there are 17 other species of mammals and 19 species of birds that can serve as intermediate hosts of B. procyonis. In raccoons, B. procyonis lives in the small intestine. In man, dogs, and intermediate hosts, B. procyonis invades body organs, the central nervous system and the eyes.
How does B. procyonis cause disease in humans and dogs?
When people or dogs accidentally ingest B. procyonis eggs, the larvae hatch and then migrate. Injury to humans and dogs is a result of the extensive damage caused by the migrating larvae. As the larvae migrate through the host’s tissues, they grow much larger in size, though they are still microscopic. Their relatively large size results in considerable mechanical damage as they migrate and the host’s body produces a very strong inflammatory response. These inflammatory reactions are a major cause of damage in the CNS.
When large numbers of larvae are ingested, the possibility of CNS disease increases. Severe signs of disease can develop within two to four weeks of ingestion. Signs of disease include loss of coordination, lethargy and stupor that progresses to coma and death.
Disease can also occur if the larvae migrate to the eye. Signs include photophobia (light sensitivity) and vision loss. Larvae migrating through other body organs can produce symptoms such as fever, enlarged liver and respiratory problems.
Since raccoons may be found in both rural and urban settings, the potential for human infection is high. Human infections have been associated with woodpiles and contaminated chimneys. Keeping raccoons as pets poses a direct threat. Wildlife rehabilitators working with raccoons and young children with poor hygiene are also more likely to be exposed.
What is the treatment for B. procyonis infection?
This is the really scary part. There is currently no treatment for B. procyonis infection in man or domestic animals. Even if a treatment is later identified, its benefit will be of questionable value since much of the damage already done by the migrating larvae is permanent.
If larvae are seen in the retina, it is sometimes possible to destroy them through laser therapy. But, again, much of the damage is permanent and eyesight may or may not improve.
Raccoons, in rehabilitation or otherwise confined, should be treated every one to two weeks for three to four treatments with any of the common wormers used to treat roundworms in dogs, e.g., piperazine, pyrantel pamoate and fenbendazole. The efficacy of ivermectin is unknown.
The powers that be had better reconsider how dangerous this can be, and the poor woman who was bitten protecting her property and pets. Heaven forbid someone’s child gets savaged by one of these large aggressive raccoons.