If you are a paranoid hypochondriacal person with young children who lives in a suburb, you’ve come to the right/wrong place (take your pick). Because now you get to hear about Baylisascaris procyonis. What’s that, you ask? The procyon part should be the tip-off, but I suppose not that many people know that Procyon is the genus to which raccoons (Procyon loto) belong. We’re going to talk about raccoon latrines.
Yes, raccoons have latrines. Who would be crazy or stupid enough to build a latrine for raccoons? Other raccoons. Raccoons have communal defecating sites called raccoon latrines where they deposit their feces and read the paper. Let me describe raccoon feces for you. Please. It’s no trouble. I want to. Fresh raccoon feces are tube shaped and have blunt ends (you’d think that would make their anuses slam shut, but that doesn’t seem to be a problem). Raccoon feces are usually dark colored (but the nature of the meal might influence this) and about the size of nickel or dime. They like to locate their latrines in existing structures, either natural or manmade. In cities or suburbs that means rooftops, attics, protrusions around roofs or chimneys, stumps, woodpiles, decks or on your lawn near your beautiful prized tree, especially in a big fork or crotch above the ground. You want some pictures?
Figure caption: Typical raccoon latrines found in urban/suburban environments. (A) Latrine on a chimney ledge, illustrating the climbing abilities of raccoons and their tenacity in maintaining latrines. (B) Large latrine in the crotch of an oak tree approximately 3.5 m (15 feet) above ground. The sides of the tree were visibly stained with fecal residue that rain had washed down the trunk, contaminating a child?s play area below with Baylisascaris procyonis eggs. (C) Large latrine, in use for years on a house roof, unknown to the home owner. (D) Latrine site on the ground near downed timber and rocks in a suburban yard. Note the variety of fecal materials (including seeds, crustacean shells, and human refuse), reflecting the diversity of the raccoon diet. The homogeneous-appearing fresh scat in the center is composed of digested pet food. (E) Latrine on a stump in a suburban park with plants sprouting from seeds in the scat. Granivorous birds and mammals are attracted to such locations, as are curious children. (F) Raccoon scat hidden in leaf litter in a suburban back yard, indicating how occult contamination may be.
Source: Roussere et al., “Raccoon Roundworm Eggs near Homes and Risk for Larva Migrans Disease, California Communities,” Emerging Infectious Disease, 2003 Dec
This is pretty unpleasant but of course animals have to go to the bathroom — I mean, visit the latrine — somewhere. Of course there is plenty to be paranoid about when it comes to raccoons. There are rabid raccoons, for example. And let’s face it, they are nasty creatures. We used to have them come onto the deck late at night at a place we rented at the beach years ago and if we tried to shoo them away they’d stand up on their hind legs and hiss at us. Brazen bastards. And they were all wearing masks, so I couldn’t identify them in the police line-up after they stole our garbage.
But the latrine thing isn’t just an aesthetic problem. Because raccoons are also frequently infected with round worms, the aforementioned B. procyonis. And if we ingest a lot of these eggs, we can get infected, too. And human infections with B. procyonis are very bad news. You can end up dead or with serious brain damage. Very young children are most likely to do this and several cases have been described that ended tragically. Human raccoon roundworm infection has been very rarely diagnosed — only 14 cases in 30 years, but 5 cases were fatal — but this is partly because extraordinary efforts are made to diagnose serious encephalitis when there are additional signs (e.g., certain blood tests) which suggest a parasite might be involved. How often less serious or even subclinical infection occurs we don’t know, but with raccoons in densely populated areas increasing, this is an emerging zoonosis (a disease spread from animals to humans) to keep an eye on.
Reported cases have been widely distributed geographically (California, Illinois, Michigan, Minnesota, New York, Oregon, and Pennsylvania) and surveys in urban/suburban areas have shown that raccoon latrines are anything but rare. A recent survey in suburban Chicago near a forest preserve and a marsh found latrines in half the yards and a quarter of the latrines had B. procyonis eggs in them. The farther from the forested area the better and having a pet in your backyard was also a good thing, although I can’t imagine our arthritic ten year old Shih-Tzu being a match for one of these guys.
Not long ago we had a raccoon in our postage stamp sized paved over backyard in the middle of the city. Mrs. R. espied it and stated quite clearly it was the size of a miniature horse. I think she may have been exaggerating slightly but it’s hard to distinguish nuance when someone is screaming. I have yet to find a raccoon latrine in the backyard, but I have applied preventive measures by removing all reading material from the area (although I understand this only works for male raccoons). If I did find a latrine, I’d want to clean it out immediately and detailed instructions how to do it can be found here.