It’s also worth noting that lice will spread from person to person. If you go untreated for a month you’re likely to cause thousands of people to become infected.
As anyone with school age children can attest.
I would say it’s the other way around. Viruses by their very nature require a host cell in which to reproduce, since they lack the ability to replicate on their own. On the other hand, parasitism is a lifestyle which has been adopted by many different types of creatures–protozoa, insects, crustaceans, nematodes, etc.
Sure. For example, various types of wasps target other parasitic wasps (e.g. Lysibia ichneumonids targeting Cotesia braconids, which are parasites of the Pieris brassicae caterpillar). This phenomenon is called hyperparasitism.
I’m not sure I understand this question.
I suppose it’s theoretically possible, if you, say, put in a suprapubic catheter to drain the urinary bladder, and make sure the dead candiru doesn’t become a nidus for bacterial infection.
rule the world!
http://www.findarticles.com/p/articles/mi_m1511/is_8_21/ai_63583791/pg_1
interesting article
Thank you for providing the term hyperparasitism.
I meant say 2 parasites occupy 1 host, which parasite will be the ones absorbing the majority of the nutrients from the host? Will either parasite hope to eliminate the other?
From that article:
Nineteenth-century biologists thought Sacculina was a hermaphrodite, but in fact it comes in two sexes
Does this mean what I think it means? O_o
That is impossible to say without knowing precisely which parasites you are talking about and the specific circumstances. You really can’t say that fleas will always extract more resources than lice, or that lice will always extract more blood than mites. If a dog has one flea and billions of lice then the lice will naturally be extracting more recourses. But one louse and millions of fleas reverses the situation.
It’s not generally beneficial for a parasite to eliminate the competition since that frees up the host immune system to concentrate on it and its progeny. Better to have the host trying to deal with multiple threats simultaneously.
If elimination does occur it will generally be through simple competition, but even that is unusual. Until a hundred year ago it was normal for a person to spend their entire lives infected by a couple of species of roundworms, at least one tapeworm species, two species of lice, fleas, mites, bedbugs and a few other parasites. All wild animals live with that sort of parasite load today, and can usually add ticks into the mix as well. The parasites never eliminate one another.
After reading that article, do modern humans fit the bill of animals which have adapted endoparasitic hyperparatismic parasitoid behaviours?
Until a hundred year ago it was normal for a person to spend their entire lives infected by a couple of species of roundworms, at least one tapeworm species, two species of lice, fleas, mites, bedbugs and a few other parasites.
By normal, did you mean the person survived or that the person died from multiple parasites infested in them?
No, that was normal. Every single person on the planet carried those parasites. Every baby would be infected by the time it was 12 months old, and the parasites would remain until the person died.
As I pointed out, any wild mammal will have the same sort of parasite diversity. The normal state of affairs is for any animal to be permanently infested by at least half a dozen different parasites. That’s 24/7 from the time they start eating solid food to the moment they die.
Modern westerners get the idea that parasites are like diseses, in the sense that they arrive and get fought off and vanish. In fact the normal state of affairs is perpetual infestation. There is increasing evidence that many auto-immune diseases and a lot of allergenicity in modern hunmans are caused or exacerbated by our lack of parasites. We evolved for so long with parasites that our bodies don’t cope well without them
Hey, as detaild in FormerMarineGuy’s link, Naegleria is a parasitic amoeba that gets in your nose, follows the olfactory nerves into your brain, and then does, in fact, chow down on your neurons until you (97% of the time) die.
I think a main character on House got a hideous brain infection from Naegleria late last season.
*We evolved for so long with parasites that our bodies don’t cope well without them
*
Whose stupid idea was it to remove parasites from our bodies? You mean to say if we had just been smart enough to keep our parasites, we won’t be in danger of AIDS or cancer nowadays?
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"So nat'ralists observe, a flea Hath smaller fleas that on him prey, And these have smaller fleas that bite 'em, And so proceed ad infinitum."*
–Jonathan Swift
No, but there is a theory that if we had more parasites we would have fewer allergies. Maybe it’s just me, but I’d rather have an itchy nose all summer than any of the disgusting things we’ve read about in this thread.
Do you have a link to that theory?
Well, here is one.
Google <parasites allergies> and you’ll find some more.
AFAIK it’s not a universally accepted idea, but it’s been seriously discussed and studied.
Ok, thanks.
Of course allergies and asthma are regularly life-threatening, which is just a tad bit more serious than an itchy nose. It is far more serious than most of the things discussed in this thread could ever do.
Auto-immune diseases are far worse than an itchy nose. Something as common as Crohn’s disease can cause unbearable pain and even death. Other autoimmune diseases can cause kidney failure, blindness, insanity and death.
In contrast a roundworm infection is unlikely to cause anyhting more serious than a an itchy butt.
Another interesting article about treating Crohn’s disease with nematodes (Trichuris suis).
Since many parasites are capable of modulating their host’s immune system locally, it makes a certain amount of sense that this could work.
You’re absolutely right, of course. Still, modern sanitation also mitagates against nasty things like cholera and typhoid fever.
It sounds sensible to me that since our immune systems don’t have as many filth-related bacteria and parasites to fight that they take to amusing themselves doing battle with peanuts, dust, and other things that are really not harmful, just “other.” And if there’s nothing else, the immune system turns on the body it’s supposed to protect, just out of sheer boredom.
I wonder, if it were proven that this relationship was genuine cause and effect, how many people with allergies would volunteer for a few bouts of tapeworms and trichinosis?
Maybe not the trichinosis, but I’d consider trading some of my allergies for a tapeworm. If nothing else, it would be a different variety of annoyance for a change.