EWW! IS THAT A PARASITE?
If the thought of an organism living off your body makes your skin crawl, relax: most of the time you won’t even notice them (and if you do, treatment is quick and easy)
ONE NIGHT, A COUPLE of hours after Allison McKenzie* put her four-yearold daughter to bed, Emma* woke up saying she felt something “down there.” McKenzie turned on the light to see what was going on and screamed: there was a small, white, thread-like worm near Emma’s vagina. Using a tissue, McKenzie shoved it in a sealed plastic bag.
The following day, a doctor looked at the specimen and confirmed what McKenzie had discovered by frantically googling in the night: Emma had pinworms. But after taking two doses of an antiparasitic drug—which was prescribed to the entire family, since the parasites can spread quickly—and cleaning both the house and the bedding, the worms were eradicated.
Most people are revolted when they find out they’ve been hosting a parasite, defined as an organism that uses other living things—like you—for food or habitat. But Dr. Jay Keystone, professor of medicine at the University
of Toronto and staff physician in the tropical disease unit at Toronto General Hospital, says parasites aren’t usually something to fear, as long as you aren’t immunocompromised.
Typically, we don’t even know we’re harbouring visitors, but we can fall ill when the organism’s numbers are significant. In such cases, it’s best to be prepared. So here are five of the most common parasites Canadians should know about.
1. GIARDIA LAMBLIA
What is it and how can I get it? This single-cell parasite takes up residence in the small intestine. Many wild or domesticated animals carry it, and people can contract it from swimming in freshwater where there is animal feces. One of the animals known to transmit the parasite is the beaver, which is why giardia lamblia is commonly known as beaver fever. It can also be passed from person to person when someone doesn’t wash their hands properly after defecating, which makes daycare centres particularly vulnerable. Another potential mode of transmission is anal sex.
I have it. Now what?
Though many people will never know they had the parasite, some will develop digestive symptoms such as watery diarrhea, nausea, bloating, fever and abdominal cramps. The illness can be easily treated with an oral antiparasitic medication.
What is it and how can I get it? Much like giardia lamblia, cryptosporidium is a single-cell intestinal parasite. It’s found in the stool of young cows, sheep and goats and can make its way into bodies of water through animal feces. Like giardia, it can also be passed around among kids at school.
Dr. Momar Ndao, director of the National Reference Centre for Parasitology and an associate professor in the infectious diseases division at McGill University, says cryptosporidium can contaminate municipal water supplies. In 2001, there was an infamous outbreak in North Battlefield, Sask., that made thousands of people sick.
I have it. Now what?
This parasite is associated with what Keystone calls “very, very severe diarrhea” that can last up to two weeks. While most healthy individuals beat it on their own, a doctor can prescribe an antiparasitic medication, though cryptosporidium doesn’t respond to treatment as quickly as giardia does.
3. TOXOPLASMA GONDII
What is it and how can I get it? Toxoplasma is a single-cell organism that lives in the blood and bodily tissues. Keystone says up to a quarter of Canadians have been infected at some point, but most don’t know it.
Toxoplasma is found in animals like cats, sheep and pigs. Often, people become infected from contact with
soil or a litter box where animal feces has broken down, or from eating undercooked meat from an infected animal. I have it. Now what?
If you do get sick, the illness may look a lot like mono: fever, enlarged lymph nodes and muscle aches. It will go away on its own, but you can ask your doctor for an antiparasitic to help.
In some cases, toxoplasma can lie dormant in the body in the form of cysts in the eye, brain and elsewhere. These cysts aren’t cause for concern—unless you become immunocompromised, in which case they can rupture. The other grave danger is if a person becomes infected while pregnant. When a fetus contracts toxoplasma, it can lead to serious birth defects like hydrocephalus and severe vision problems, or miscarriage. Ndao stresses that anyone who is pregnant should avoid litter boxes.
What are they and how can I get them?
Ndao says that a very high proportion of children will become infected with pinworms at some point. Most sufferers don’t know they have these worms, which live in the lower bowel—unless they’re tipped off by itchiness at their rectum or in their vagina. Kids are most commonly infected because of improper handwashing and scratching at the site, then putting their fingers in their mouths, causing them to ingest pinworm eggs. I have them. Now what?
Pinworms can be treated with a pill that’s repeated 14 days later, but to prevent reinfection it’s important to wash hands regularly, wear underwear and pyjamas to bed, thoroughly wash the sheets and clean the house—the tiny eggs can survive for a week in the dust around your home.
What is it and how can I get it? Scabies is a skin condition caused by ectoparasites—mites that live and feed on the skin. These mites are among the most commonly contracted parasites and are spread through touch. Though scabies isn’t necessarily sexually transmitted, it’s often shared through prolonged skin-to-skin contact. Less frequently, it can be spread through towels, clothes or linens. The microscopic mites cause an itchy rash that will continue until you’ve tackled it.
I have it. Now what?
Fortunately, treatment is quite simple and usually involves applying a topical cream twice, cleaning your sheets and containing recently worn clothes in a sealed bag for a few days. If you’re immunocompromised, however, mite populations can grow rapidly and cause an infestation called crusted scabies. While a regular infection might involve approximately 10 mites, crusted scabies can involve thousands or even millions and may lead to a much more severe rash.