Baylisascaris is a genus of roundworms that infect more than fifty animal species.

Life cycle

Baylisascaris eggs are passed in feces and become active within a month. They can remain viable in the environment for years, withstanding heat and cold. Animals become infested either by swallowing the eggs or eating another animal infested with Baylisascaris. Despite lack of larvicidal effects, albendazole (20–40 mg/kg/d for 1–4 weeks) has been used to treat many cases.

Baylisascaris species

Each Baylisascaris species has a host species that it uses to reproduce. The eggs appear in the host species' feces. They can then be ingested by, and infest, a variety of other animals (including humans) that serve as paratenic hosts.

Baylisascaris species include:

  • Baylisascaris procyonis (of raccoons)
  • Baylisascaris melis (of European badgers)
  • Baylisascaris transfuga (of bears)
  • Baylisascaris columnaris (of skunks and American badgers)
  • Baylisascaris devosi (of fishers and martens)
  • Baylisascaris laevis (of marmots)
  • Baylisascaris schroederi (of giant pandas)
  • Baylisascaris potosis (of kinkajous)

Baylisascaris procyonis

Baylisascaris procyonis is found in the intestines of raccoons in North America, Japan and Germany. It infests 68 to 82% of some raccoon populations, according to the House Rabbit Society. According to the Michigan Department of Natural Resources, nearly 100 percent of raccoons in the Midwestern US are infected. This parasite can be extremely harmful or deadly to humans. The exact proportion of skunks that are infested is unknown. Since the worms are often at too early a stage in development to begin shedding eggs into the feces, a fecal test may not detect the parasite, and the pet should be pre-emptively treated with dewormers antiparasitacides.

Baylisascaris eggs are highly resistant to decontamination procedures because of their dense shell and sticky surface. They can survive hot or freezing weather and certain chemicals, remaining viable for several years. Bleach can prevent the eggs from sticking, but will not ensure destruction. According to Parasitism in Companion Animals by Olympic Veterinary Hospital, hand washing is an important countermeasure against ingestion, and decontamination of other surfaces is accomplished by thoroughly flaming with a propane torch or treating with lye. Other forms of high heat such as boiling water or steam will accomplish the same result. Children are more likely to be infected than adults because of their tendency towards pica, particularly geophagy. In spite of the numerous raccoons living in close contact with humans, less than 30 serious infections of humans by Baylisascaris had been reported by 2012; but it is thought that some cases are misdiagnosed as other infections or are never identified.

See also

  • List of parasites (human)

References

  • Old Rabbit Paralysis Part III: Baylisascaris Procyonis House Rabbit Society
  • Baylisascaris procyonis in Dogs, D. D. Bowman, Department of Microbiology & Immunology, College of Veterinary Medicine, Cornell University, Mar. 11, 2000.
  • Information on Parasites in Skunks by Matt Bolek, Diagnostic Parasitologist (link via InternetArchive, as original page no longer valid).
  • Parasitism in Companion Animals by Olympic Veterinary Hospital.
  • Baylisascaris procyonis: An Emerging Helminthic Zoonosis, Centers for Disease Control.