| Baylisascaris | |
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| Baylisascaris procyonis larvae | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Nematoda |
| Class: | Chromadorea |
| Order: | Ascaridida |
| Family: | Ascarididae |
| Genus: | Baylisascaris Sprent, 1968[1] |
Baylisascaris is agenus ofroundworms that infect more than fifty animalspecies.[citation needed]
Baylisascaris eggs are passed infeces and become active within a month. They can remain viable in the environment for years, withstanding heat and cold.[2] Animals become infested either by swallowing the eggs or eating another animal infested withBaylisascaris.[2]
After an animal swallows the eggs, the microscopiclarvae hatch in theintestine and invade the intestinal wall. If they are in theirdefinitive host they develop for several weeks, then enter theintestinal lumen, mature, mate, and produce eggs, which are carried out in the fecal stream. If the larvae are in aparatenic host, they break into the bloodstream and enter various organs, particularly the central nervous system.A great deal of damage occurs wherever the larva try to make a home. In response to the attack, the body attempts to destroy it by walling it off or killing it. The larva moves rapidly to escape, seeking out the liver, eyes, spinal cord or brain. Occasionally they can be found in the heart, lungs, and other organs. Eventually the larva dies and is reabsorbed by the body. In very small species such as mice, it might take only one or two larvae in the brain to be fatal. If the larva does not cause significant damage in vital organs, then the victim will show no signs of disease. On the other hand, if it causes behavioral changes by destroying parts of the brain, the host becomes easier prey, bringing the larva into the intestine of a new host.[citation needed]
Are the following:[citation needed]
Whiledeworming can rid the intestine of adultBaylisascaris, no treatment has been shown to alleviate illness caused by migrating larvae.[3] Despite lack of larvicidal effects,albendazole (20–40 mg/kg/d for 1–4 weeks) has been used to treat many cases.[4]
EachBaylisascaris 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.[citation needed]
Baylisascaris species include:
Baylisascaris procyonis is found in the intestines ofraccoons in North America, Japan and Germany. It infests 68 to 82% of some raccoon populations, according to theHouse Rabbit Society.[7] 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.[3]
Skunks carryBaylisascaris columnaris, a similar species toB. procyonis. Many pet skunks have died from this parasite.[citation needed] According to several skunk experts, many baby skunks from skunk farms haveB. columnaris present in their bodies.[8] 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.[citation needed]
Baylisascaris eggs are highly resistant to decontamination procedures because of their dense shell[citation needed] and sticky surface.[citation needed] They can survive hot or freezing weather and certain chemicals, remaining viable for several years.[citation needed] Bleach can prevent the eggs from sticking, but will not ensure destruction.[citation needed] 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 withlye.[9][better source needed] Other forms of high heat such as boiling water or steam will accomplish the same result.[citation needed] Children are more likely to be infected than adults because of their tendency towardspica, particularlygeophagy. 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.[citation needed]
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