You can get Hulda's book in PDF here:
http://books.bioelectrification.info/Cure%20for%20all%20Diseases%20(Hulda%20C...

I will share my understanding. But please keep in mind that I have no scientific training. My explanation may be grossly inadequate. My comprehension is probably limited.

Tapeworms are segmented. Segments can break off from the original worm, dig in and start another worm. I guess they sort of like clone themselves via these segments, or something. I don't think they can be categorized as males or females.

Ascaris lay eggs to reproduce. The females are bigger than the males. They can lay 200,000 eggs per day. The eggs are microscopic and most of them are eliminated with bowel movements.

If you have a parasite, you are probably susceptible to getting more of them, otherwise you wouldn't have gotten the first one. If you have several of them, it is a colony.

Some parasites are microscopic. Most people would rather think of them as germs. parasites can live in hair shafts, the blood stream, between the teeth and gums, the brain, the joints, the bone marrow, the organs, every tissue of the body, and on the skin.

Perhaps DNA is what determines susceptiblity as there are sequences, or alleles, that code for specific genes. But genetic expression requires a certain environment. Maybe a toxic body and nutritional deficiency is what provides the proper condition for genetic diseases to manifest?

People who would rather believe disease is caused by germs, than entertaint the possibility that they have parasites, are more likely to go to the doctor and get a prescription when they feel sick. But doctors frequently fail to give people a large enough dose to kill the entire colony, and they never educate people on how to strengthen their immune system by avoiding toxins and getting adequate nutrition and exercise. The prescription kills off some of the parasites, and the patient (why do they call them "patients", what are they patiently waiting for? death?...anyways...)the patient feels a whole lot better, temporarily.

But the remaining parasites begin to recolonize, and in a few weeks, months, or years, the person is feeling sick again. Parasites are very smart. I guess you could say they were programmed for survival. When they recolonize, they frequently come back resistant to the drug that killed them the first time. That is why pharmaceutical companies are constantly coming out with new drugs.

Some scientists argue that such an approach is simply breeding super strains and a plague is coming.

Some people say the good bugs inside of you morph into bad bugs if you aren't living a healthy and balanced lifestyle. But how can you do that if all the food is nutritionally deficient because they've sprayed it with chemicals, picked it before it was riped and irradiated it before it gets to the grocery store, and the water we drink is contaminated?

I kind of think it is a combination of both.

If the colony infecting you is internally generated. In other words, if you have a gene, that is expressing itself, causing otherwise synergistic organisms to morph into meanies, perhaps they will morph back into something helpful, if you change your lifestyle. Maybe that is the case with diabetes. I say that because Hulda Clark e said she never saw a case of diabetes that wasn't accompanied by pancreatic flukes. And people with diabetes, who take chromium, can reduce their need for insulin. But there are some genetic "illnesses" that are not so quickly and easily improved, and may not be of parastic origin, such as down's syndrome. Or is it? I once read the testimonial of a woman who said she changed her daughters facial features with diet.

If the colony infecting you was an opportunistic foreign invader, and you manage to eliminate the queen and all her babies, in the case of a hive, or the head, in the case of a tapeworm, or all the mothers and fathers, in the case of ascaris, then you won't have any more problems unless you ingest, inhale or otherwise "catch" them again. I'd bet a million dollars if I had it, that demodex are transferring from other people, onto me, whenever I give people a hug, and make skin to skin contact, because every time I do, I get a pimple or two. And I've gone months without having any pimples at all, but only by strict isolation, being very careful not hug anyone in a way that allows skin contact.

Maybe if you don't have the gene, you won't get any pimples? But even people without pimples, or so few pimples you don't notice them?, or such tiny pimples that you can't seem them?, have demodex, it seems to me, as I catch them from people that don't appear to have any pimples, because if I give them a hug, I get a pimple.

Why is that? I don't know. I can only guess that it has something to do with genetics. For whatever reason, some people's immune system is strong enough to keep demodex colonies from flourishing and making acne.

I vote for extinction of parasites. I invite all parasites that wish to continue to exist, to morph into a synergistic species. Synergistic organisms that are beneficial to my health and well-being, are welcome to live on me, in me, as me. If they make me feel sick, my job is to take a look at my lifestyle and diet, make sure I am living a balanced life. If I am, and they refuse to leave my body, then I am declaring war on them. It will take a collective conscious effort to extinguish parasites from the human species. It may not happen in my life time. But I am determined never to give up.