Creature Comforts: Parasites, masters of stealth mode

Creature Comforts

I find it interesting that the first definition for “parasite” in Webster’s Dictionary is “(noun) A person who exploits the hospitality of the rich and earns welcome by flattery.” A people-centered, figurative interpretation of the real thing — we have redefined the term such that the number one usage is all about humans.

Webster’s chooses to place the genuine biological parasite definition second, defining it as “an organism that lives in, with or on another organism.” Unsurprisingly, actual, bona fide parasites are always playing second fiddle, even when being defined!

The thesaurus gets even more people-y, with “parasite” listed as “a person who is supported by or seeks support from another without making an adequate return,” with no mention at all of the creatures that gave us the idea in the first place.

There are lots of fun synonyms for the word “parasite” provided by both sources: Blood sucker, free rider, freeloader, hanger-on, leech, moocher, sponge, sponger. I take issue with the last two, from a biological standpoint.

Sponges (the living things that dwell in the ocean, not the man-made, rectangular, crusty, sour-smelling object in the kitchen) get a bad reputation, but they aren’t actually parasites. Just because they sit around attached to the sea bottom doing nothing but filtering nutrients from the water all day doesn’t mean they’re parasites — they may not lead very exciting lives, but they are quite independent.

Words related to “parasite” are overall, pretty derogatory: Dependent, deadbeat, idler, flunky, henchman, lackey, satellite, stooge, sycophant, toady, yes-man, cheapskate, miser, piker, scrooge, skinflint, tightwad.

I’d say, other than “dependent,” most of those are (or should be) kind of insulting to true parasites. After all, they’re just trying to make a living.

We see it as taking advantage of another creature, but to them, it’s just sharing. Never mind that it’s without the other being’s knowledge or consent, and may be detrimental to their health. Technicalities.

In nature, there is no “right” or “wrong.” Humans are unique in attaching moral significance to stuff.

Creatures from the tiniest bacteria to the massive whales in the ocean all have the same life strategy: To survive long enough to reproduce. That’s pretty much it. Being comfortable and not struggling to survive is a bonus, but not a requirement. In the wild it’s “eat or be eaten.”

So, parasites have simply found ways to survive that take advantage of a sweet situation, and have adapted their life cycles to capitalize on an untapped market, so to speak.

There’s an adage we were taught in veterinary school: “A good parasite doesn’t kill the host.” Sounds almost metaphorical or philosophical, but its meaning is quite literal. Any good con-man will agree: Imitate the genuine article, and you’ll escape detection and be living on Easy Street for a good, long time.

Whether you’re a miscreant siphoning off cash from the till or a parasitic worm siphoning nutrients from deep in your host’s intestines, it’s most important to employ stealth, patience and moderation to escape detection avoid damaging the host, or the whole business goes bankrupt, and then you’ve got yourself in a real pickle. It’s a long con, so to speak; in some cases, life-long.

Nature’s best parasites have had oodles of time to get things just right — some have been around since life on the planet was just beginning. Survival of the fittest, and all that.

Diving into the world of parasites introduces one to a rag-tag cast of characters that are so sneaky, yet so creative in their ability to coexist surreptitiously with their hosts, their life strategies seem ingenious and elegant. In a totally gross and repugnant way, of course, but still admirable in the execution.

In my business, we deal with a whole bunch of strange and interesting parasitic infestations and illnesses. Because we work with several different species of animals, each with their own set of parasitic beasties that, in turn, have their own unique life cycles — and THEN must know when (or whether) to treat the patient and with which medications (which are always changing, with advances in pharmacology) … there’s a lot to know.

In veterinary school, my husband (then boyfriend), while studying his thick stack of hand-crafted flash cards late one night for a parasitology exam, bemoaned in a fit of emotional fatigue, “My head is full of worms!” Indeed.

Tune in next time for some weird and wonderful life stories of my favorite parasites and what to do about them. Stealth mode — engage!

— Daverio is a veterinarian at Williamsport West Veterinary Hospital. Her column is published every other Sunday in the Lifestyle section. She can be reached at life@sungazette.com.


Seek and ye shall find: Nestled amongst a microscopic field of red blood cells is a tiny Heartworm microfilaria, an immature, larval form of this parasitic worm. When mature, it will grow to be 12-inches long and live in the vessels of the lungs and heart.


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