The likelihood of you getting sick from pond water is remote. If your fish were releasing Camallanus, I suppose you could swallow them and they could set up in your intestinal tract. That is extremely unlikely. (People who have had to be treated for Camallanus ate undercooked infected fish, usually in subtropical or tropical areas.)

I have a slide around here somewhere of a shot of a drop of sea water at low magnification. It is amazing all the critters in there. Limnologist Terry Fairfield has been looking at local lake and river critters through a 'scope for years. When he started looking at aquarium water, he was startled to see much the same crowd! Unless bacteria levels are real high, we seem to be pretty impervious to that stuff in temperate areas, it pollution isn't too great. (He says, whistling in the dark.)

The most commonly caught disease by aquarists, which happens to be in their extremities, is fish tuberculosis. The two possible species are not the TB (or Mycobacterium) which attacks the lungs of people. The fish TB species are designed to live in the 70s F/21-26 C or about the temperature of the skin on our hands. It has had a fair amount of coverage in the last 30 years and "fish keeper's finger" can be treated with antibiotics. I know of a guy in the 35-45 year-old range who saw it clear up in a couple of days. A guy in his 70s endured antibiotic treatments for six months. Like the fish, our immune systems become less efficient. Wash all cuts received around aquaria and probably ponds. Then rinse the cut with hydrogen peroxide until all "fizzing" is gone. (I use an eye dropper.)

Those critters are actually fairly common in aquarium waters. If you swallowed them, it is extremely unlikely that you would be bothered by them. Your insides are the wrong temperature.

Angelhologram raised the issue here of zoonotic diseases (or diseases we can catch from animals). In the last century a lot of Americans, especially on the frontier and where sanitation was casual, died of Cholera and Typhoid fever. That still kills too many people in the world.

You might want to Google zoonotic diseases.

The old People's Encyclopedia claimed that amoebic dysentery killed more people annually than any other disease in the world. Usually they are weakened by the diarrhea and then finished off by something else. Those tragedies tend towards tropical and subtropical areas.

There may be as many as a billion people in this world who still do not have clean water supplies.

In some parts of the world there are some terrible diseases, which are in the water and they are spreading from one tropical region to another. Schistosomiasis, which uses snails and mammals (including people) as alternate hosts has spread from African especially to northern South America and can be found in tropical Asia as well. (Not only don't drink the water, don't swim in it recreationally if it isn't strongly chlorinated.) I am acquainted with a guy who has done a lot of research on killies in Africa. He lives a normal life, but I guess he underwent treatment for Schistosomiasis for some time.

Son of a gun, Praziquantel is one of the more effective treatments for both the intestinal and urinary forms of Schistosomiasis. That gentleman I referred to is the sort to always get his preventative shots before going to the tropics and he still got nailed. I can just imagine what he might have gotten without all those shots.

We hear about bull sharks, crocodiles, piranha, candiru and stingrays and those creatures can be very dangerous. But it the microscopic and almost microscopic ones which are really dangerous for most of us

Freshwater, is it fair to assume that you fell into a temperate pond? (Love your e-mail addy.) You said it was very cold.

Looking at and thinking about your e-mail address, you probably know a lot more about this stuff, then I do. Please pardon any presumptuousness in what was said.

As a person entirely unqualified medically to comment upon your case, I still hope the chill passes quickly and is nothing more. :)

All the best!