Humans have been living and co-existing with intestinal parasites for millions of years. Our bodies and immune systems have been evolving the whole time to deal with them.
There is no need to freak out about every germ around, to disinfect and sterilize everything you touch and to live in a bubble.
Yes, worms can cause health problems in humans and in dogs, as can any of the TRILLIONS of bacteria that colonize our gut.
Bottom line is that unless you're badly malnourished or extremely sick or have no immune system for whatever reason, your average worm isn't going to hurt anyone.
The best thing to do is focus on being as healthy as possible, eat a variety of fresh species-appropriate food, get plenty of fresh air, sunlight, clean water, exercise and be happy.
If you've been well exposed to your environment since you were young, you will have built up all the resistance and immunity you need against your everyday parasites and bugs.
I don't think that the key to good health is confining oneself to a sterile bubble, eating nothing but lifeless processed foods (god forbid you touch anything raw in case it has a germ on it!!), swallowing toxic drugs to kill off any potential microorganism and generally avoiding contact with the outside world for fear of picking something up.
The concept of hyper-sterility has been studied for a long time in animals. Labs can create gnotobiotic animals for study - basically these animals are born into sterility (via C-section, no contact with the mother's birth canal) and raised in a 100% sterile environment so that they have absolutely 0 contact with microorganisms from the environment.
Many studies have been done comparing the development of these "germ-free" animals (raised in a sterile environment) with sibblings or other litters that were raised "normally", with full exposure to the outside environment.
The gnotobiotic animals actually grow quicker and end up larger than their "germy" counterparts of the outside world, as long as they're kept in their little bubble of safety.
However, these animals can barely survive if they're placed in a normal everyday environment. They get sick from everything all the time and can't handle the meekest of germs. Their immune systems are incompetent and they need constant drugs and treatment to stay alive.
The normally raised animals had no problems at all keeping parasites under check without any kind of human interference and thrived.
The lesson from all this?
CALM DOWN ALREADY!!
If our bodies weren't designed to deal with all the little germies out there, we humans would not exist.
I grew up eating plenty of raw fish, raw eggs and yes, even some raw meats (properly prepared) from the time I was a baby. Raw fish & eggs are frequently used in traditional Japanese dishes and my family has been eating this way for hundreds of generations. I have always eaten huge amounts of sashimi (raw fish) and have never, not once in my life, been the slightest bit sick from that.
I go swimming in lakes, I get covered in mud pretty much daily cause of the dogs, I have my dogs indoors with me, I pet them without washing my hands each time, I let them lick my face and no, I do not bombard them with toxic insecticides (frontline anyone? sentinel?) month after month their whole lives.
According to most doctors and vets, my dogs and I should be dead by now.
If anything, I've noticed that I'm particularly resistant to food poisoning. There were plenty of times where I've eaten out with friends while traveling abroad and they'd get digestive upsets pretty easily from foods that were more "germy" than the sterile stuff they were used to eating at home.
I never got sick from any of it. And I've sampled some pretty... "exotic" dishes over the years too.
Compare some kid raised on a farm around animals to a kid kept in a highly sterilized environment his whole life.
Guess which one is far more likely to have a robust immune system and great health and which one is going to have allergies to everything and get sick every time he touches a germ?
This is nuts. There is no proof anywhere that frantically battling to eliminate ALL germs and parasites from an animal's body and environment result in improved health.
Quite the contrary... that kind of strategy is going to cause a lot more problems than it solves.
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Ok, I'm done... that came out a little longer than I intended. What a surprise