Raccoon roundworms – the hidden horror

By Anthony Olszewski

“It’s often an autopsy diagnosis; it’s horrible.”
http://www.microbe.tv/twip/twip-125/ (Around 73:00)
Dr. Daniel Griffin, MD and a co-host of the Podcast, “This Week in Parasitism” at Microbe.tv.

Raccoon at outdoor cat food dish in Jersey City
What’s for breakfast!
A local volunteer caring for outdoor cats found this new face at the feeding station one morning.

Baylisascaris procyonis is a roundworm (similar to those commonly found in dogs and cats) carried by many raccoons. In the small intestine of the raccoon, this roundworm may be little more than a nuisance. The eggs are spread by raccoon dung.

Baylisascaris also infests a wide range of birds and mammals – including people. When Baylisascaris finds itself in animals other than raccoons, it bores through the intestinal tract, attacking the liver, lungs, eyes and brain.

Raccoon roundworms can be a death sentence for pigeons, doves, parrots, chickens and other birds.

Raccoon roundworm larva in a cross section of a human brain.

Raccoon roundworm larva in a cross section of human brain tissue.

In humans, detection is often difficult and too often too late. Debilitating illness, blindness, permanent afflictions and death can result. And the cases of disease discovered by doctors quite likely are far from the total number of infections. People are big so a small number of roundworms tunneling through tissue may only cause non-specific symptoms. (The eye is an exception. If only one of the parasites gets there, serious damage results.) This is far from good news. Even if the parasite fails to send a victim to an emergency room or a morgue, there’s no such thing as an acceptable number of worms eating away at the brain or other organs.

The raccoon long was an icon of the deep forest and only was expected to be found there. Indeed, the coonskin cap is associated with Davy Crockett and other frontiersman. When raccoons just inhabited rural areas, city dwellers had no reason to worry about Baylisascaris. This now is the strange new One World that has such diseases in it. Like viruses of the African rain forest that have made their way to New York, parasites of the back woods now can be found here. Raccoons — and their roundworms — reside in Manhattan, the other Boroughs and throughout the Metropolitan area.

A specific risk to public health is the increasingly common – and publicly promoted – caring for outdoor cats, if not responsibly done. Large quantities of food placed out at night or before dawn will surely attract raccoons. Regularly eating somewhere, raccoons will be regularly relieving themselves nearby and so posing a danger to people. As raccoons are secretive and only active after dark, most people will never see them. Once the animal excrement becomes part of the soil, that hides the roundworm eggs. People – especially children – then can be easily infected.

Community cats eating in street

The managing of colonies of outdoor cats is important, but must be properly implemented.

The answer is not the elimination of cats or the persecution of raccoons, but common sense. Feed community cats after sunrise and well before sunset. Only put out as much as the felines will consume, not leaving any extra for “guests.” Raccoons are native animals and so they are our neighbors. These furry fellows with the bandit mask have every right to live their lives in peace.

Anthony Olszewski is the founder of Metro Cat Rescue.

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Baylisascaris Larva Migrans
USGS Circular 1412
By: Kevin R. Kazacos

Baylisascaris procyonis-the raccoon roundworm
Professor Emeritus of Veterinary Parasitology at the Purdue University College of Veterinary Medicine, Kevin Kazacos, DVM, PhD talks on Outbreak News Today about this little known, but very dangerous parasite.

Parasitic Diseases, 6th Edition – Free Download

One thought on “Raccoon roundworms – the hidden horror”

  1. “…
    A Possible Agent of Bioterrorism

    In an era of increasing concern about bioterrorism (33), certain characteristics of B. procyonis make it a feasible bioterrorist agent. The organism is ubiquitous in raccoon populations and therefore easy to acquire. Enormous numbers of eggs can be readily obtained, and these eggs can survive in an infectious form for prolonged periods of time. As with other ascarids, the eggs can remain viable in a dilute (0.5%-2%) formalin solution for all indefinite period of time, and animal studies suggest that B. procyonis has a relatively small infectious dose. Moreover, the organism causes a severe, frequently fatal infection in humans, and no effective therapy or vaccine exists. Introduction of sufficient quantities or B. procyonis eggs into a water system or selected food products could potentially result in outbreaks of the infection. A similar agent, Ascaris suum, a roundworm of pigs, was used to intentionally infect four university students who required hospitalization after eating a meal that had been deliberately contaminated with a massive dose of eggs (34). Contamination of community water sources would be difficult since the eggs of B. procyonis are relatively large (80 [micro]m long by 65 [micro]m wide) and would be readily removed by standard filtration methods or the flocculation and sedimentation techniques used by municipal water systems in the United States. However, posttreatment contamination or targeting of smaller systems could be possible.


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