When I had a parasitology course (30+ yrs ago). This "guy" was not really much of a problem in the US. Now apparently it is - however, only in certain locales. I guess, theoretically, it could be most anywhere infected canines are. These infected canines defecate in or near (run-off from rain) water, the eggs find their way into the water supply. As I recall, all Cestode (all tapeworms, incl. hydatid tapes) eggs are very "hardy" & can survive for extended periods of time outside of a host.
Like many (not all) parasites, they may have more than one type of host. A host for each stage of its development. Canines are what is called the definitive/final host, i.e. the host that the adult tapeworms live in. Unlike beef, pork, fish tapes, Echinococcus granulosis is somewhere b/t 5-8 mm long (if memory serves) - not 10's of feet long. Intermediate hosts, e.g. sheep, cattle, pigs, humans, & some others (i forget the others specifically) become infected by ingesting the eggs that are released in the stools of the primary host. The eggs release an intermediate developmental stage (larvae) of the tape that further leaves the intestines & travels to other organs in the body (liver & lungs being the main ones in humans). They grow there for yrs, hence the need for surgery to remove the cysts, that are compromising organ function, & that could be a couple of inches in diameter. If the cysts rupture during removal or spontaneously (??? can't recall how often this happens), infection spreads & the cycle starts over, -OR- the person may die from anaphylactic shock - basically, the body having an "allergic" reaction to the strange chemicals & proteins suddenly released when the cyst(s) ruptures - often breathing stops as a result of the anaphylactic shock & death ensues.
I think infection rates are around 1 in a million for humans or less in the US, but this should be verified - very, very low. But, if you just happen to be in an endemic area, who knows? In other countries it is 10x higher than in the US. Keep in mind my figures/rates may not be current figures.
There are two other species of hydatid tapes that are problems for humans. I never learned anything about them though, so have nothing to pass on. There are at least a couple of physicians who have posted to these forums. Perhaps they would be kind enough to share their knowledge with us if they read this and are so inclined. My med. knowledge is certainly not on the same playing field as theirs - mine being only that which comes from being, many yrs ago at different times, a corpsman & a microbiologist. Any Nurses please chime in also. I'm sure y'all know more than I do. Dr. J, do you know anything about hydatid tapes in the US?
Humans cannot be infected by eating other infected intermediate hosts (the little "guy" doesn't work this way). Canines become infected by ingesting the cysts in the organs of the intermediate hosts, however.
I've emailed McNett to ask them if AqM is effective in killing the eggs, also dosage & contact time. I've also email Hydro-Photon the mfr. of Steri-pen w/the same questions. Also, what treatment time for 0.5-1.0 L of water. Dr. J, do you know anything about AqM's effectiveness against tape eggs? Or, UV-C for that matter? Any info would be greatly appreciated.
Boiling (literally) water is supposed to work. Can't say for sure for how long - prob. minutes of boiling to kill the eggs. Not terribly fuel efficient.
I do believe that filters should work to remove the eggs from the water. I still haven't found the size of the eggs fr/my old notes, but I don't see why they should be smaller than protozoans, since these buggers are much, much larger than protozoans when mature - usually the size of things goes up as the creature's position near the overall bottom end of the taxonomic scale rises. I've seen the eggs & other developmental stages under a microscope, but can't remember the sizes - other than probably for the adults. I tred a web search to find out the size of the eggs, but didn't come up with anything. Based upon one website G.R. sent me, it may be 25 microns - so filters, even just cyst filers with larger pore sizes (these are effective against protozoans, not bacteria), would work fine.
I don't think there is much reason to worry unless going to an endemic area (G.R. has informed me Isle Royale is one).
Sorry to be so long winded. 'nuff said (by me at least).