Raccoons from the NEWC and Balisascaris procyonis egg with larvae
Raccoons from the NEWC and Balisascaris procyonis egg with larvae

Since I have moved to Iowa, I have met more and more people who keep raccoons as pets. Yes they are adorable and smart, but it is very unsafe for both the animal and the household, and it is illegal!

What is Baylisascaris

Baylisascaris procyonis is a roundworm found in raccoon feces. Raccoons are infected with Baylisascaris when they consume the parasite eggs during foraging, or come into contact with infected feces at a latrine (a communal excretion site).

The parasite fully develops in the intestines of the host raccoon and produces millions of eggs which the host then passes in the feces.  After 2 to 4 weeks of development outside of the host, the eggs can cause an infection. The eggs are extremely resistant to the environment and can lay dormant for years.

Susceptibility and Symptoms:

Humans and household pets can be infected by Baylisascaris procyonis by coming into contact with raccoon feces or inhaling fece particles. Children and pets are the most susceptible because they often but foreign and dirty objects in their mouths.

"Baylisascaris procyonis completes its life cycle in raccoons, with humans acquiring the infection as accidental hosts (dogs serve as alternate definitive hosts, as they can harbor patent infection and shed eggs). Unembryonated eggs are shed in the environment The number 1, where they take 2-4 weeks to embryonate and become infective The number 2. Raccoons can be infected by ingesting embryonated eggs from the environment The number 3. Additionally, over 100 species of birds and mammals (especially rodents) can act as paratenic hosts for this parasite: eggs ingested by these hosts The number 4 hatch and larvae penetrate the gut wall and migrate into various tissues where they encyst The number 5. The life cycle is completed when raccoons eat these hosts The number 6. The larvae develop into egg-laying adult worms in the small intestine The number 7 and eggs are eliminated in raccoon feces. Humans become accidentally infected when they ingest infective eggs from the environment; typically this occurs in young children playing in the dirt The number 8. Migration of the larvae through a wide variety of tissues (liver, heart, lungs, brain, eyes) results in VLM and OLM syndromes, similar to toxocariasis The number 9. In contrast to Toxocara larvae, Baylisascaris larvae continue to grow during their time in the human host. Tissue damage and the signs and symptoms of baylisascariasis are often severe because of the size of Baylisascaris larvae, their tendency to wander widely, and the fact that they do not readily die. Diagnosis is usually made by serology, or by identifying larvae in biopsy or autopsy specimens."
This image was taken from the CDC website

Once ingested, the eggs incubate for 1 to 4 weeks and then hatch inside of the body. The larvae then travel through the body to affect areas like the central nervous system, the visceral nervous system, and the eyes. Since humans are just an intermediate host, the roundworm does not complete its whole lifecycle, so the larvae will not mature in the intestines and eggs will not be present in the feces2. Instead, they continue to feed on the host and can lead to severe problems, including death.

Symptoms are very similar to that of a cold or the flu, which makes diagnosis difficult. They include:

  • Nausea
  • Tiredness
  • Irritability
  • Fever

More severe symptoms include3:

  • Seizures
  • Altered mental status
  • Loss of muscle control and coordination
  • Lack of attention to people and surroundings
  • Liver enlargement
  • Macular rash
  • Abdominal pain
  • Blindness
  • Coma
  • Migraines

Depending on the extent of infection, the targeted areas, time of diagnoses and treatment, a Baylisascaris infection can be deadly.

To best protect your self, family, and pets, from Baylisascaris, observe wildlife from a distance and do not keep wild animals as pets. also, make sure to keep clean hygiene practices like washing hands and not sticking foreign objects in your mouth. For more information visit the CDC Prevention & Control page

Baylisascaris infections very rare, fewer than 25 cases have been recorded in the U.S. However, since symptoms are common among other disease, it is possible that more cases have occurred and have been misdiagnosed or undiagnosed2.

Known Locations2:

  • California
  • Illinois
  • Louisiana
  • Massachusetts
  • Michigan
  • Minnesota
  • Missouri
  • New York
  • Oregon
  • Pennsylvania

Baylisascaris procyonis infections are very rare in humans, but they are possible. People should always take caution around and respect wildlife. Baylisascaris is one of many reasons why wild animals, like raccoons, should not be kept as pets.


Citations:

  1. Parasites – Baylisascaris Infection. CDC. 2016 May 24 [accessed 2016 Oct 31]. https://www.cdc.gov/parasites/baylisascaris/
  2. Epidemiology & Risk Factors. CDC. 2016 May 24 [accessed 2016 Oct 31]. https://www.cdc.gov/parasites/baylisascaris/epi.html
  3. Disease. CDC. 2016 May 24 [accessed 2016 Oct 31]. https://www.cdc.gov/parasites/baylisascaris/disease.html

 

5 thoughts on “Raccoons and Baylisascaris”

  1. Nice blog! Your information was relevant to many in the public and logical to follow. Your use of figures was very effective in supplementing your writing.

  2. Your post is really interesting ! I have never heard about such disease exist and raccoons can be a definite host for it . I am just curious whether ferret can be infected with this same kind of worm or not ?

  3. This is pretty disgusting to think about! Good thing you sounded the alarm.
    I almost didn’t click on the link under the picture–just thought it was part of the caption.

  4. I had no idea that this type of parasite existed. Are the known locations listed locations where humans have been infected, or locations where raccoons have been infected with this parasite? Does this parasite only get transmitted through feces, or can it be transmitted through eating raccoon meat?

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