Hydatid Tapes

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    paul johnson


    Locale: LazyBoy in my Den - miss the forest

    Does anyone know if Aqua Mira is effective in killing the eggs of Echinococcus granulosis & other species of hydatid tapeworms?

    If so, how many drops of each & what is the contact time.

    Only found out recently that this is now a problem in the US as it has been a problem for yrs in other countries.

    Potential for human infection exists in waters that have had infected canines (including wolves, coyotes, feral & domestic dogs, & foxes) defecate in them. Risk is apparently low in the US, but the disease is very severe as it generally won’t be detected for 5-20 yrs & will require extensive surgery to remove the cysts. Death from anaphylactic shock is a possibility.

    Mike Storesund


    Holy cow… if it takes anywhere from 5 – 20 years to detect, that might make the source almost impossible to locate.
    PJ, do you know if this is something the canine actually has to defecate in or can it be introduced by an increase in water level after the fact?
    Also, is there an article on this elsewhere that can offer more detailed information?

    paul johnson


    Locale: LazyBoy in my Den - miss the forest

    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).

    Jim Colten
    BPL Member


    Locale: MN

    Tape worms are an issue at Isle Royale NP. Below is what their drinking water page says about treatment.

    WARNING! Water not obtained from spigots in Rock Harbor or Windigo must be considered contaminated with intestinal bacteria and the eggs of the hydatid tapeworm. Boil water for at least two minutes or filter through an adequate filter (0.4 microns for bacteria; 25 microns for tapeworm). Halizone tablets, bleach, and other chemical purifiers WILL NOT kill tapeworm eggs although they may be effective against bacteria if used properly. PLAY IT SAFE!

    paul johnson


    Locale: LazyBoy in my Den - miss the forest

    As promised in a prev. post, here is McNett’s very timely reply:
    Hi Paul,

    Thank you for your inquiry.

    Since we have not specifically tested Aquamira against the hydatid tapeworm (or E. granulosus) we cannot advise you in this instance.

    Chlorine dioxide, Aquamira’s active ingredient, is shown to be effective in eliminating pathogens including bacteria, viruses, and protozoans (such as Giardia and Cryptosporidium) in drinking water. Chlorine dioxide is considered a much stronger disinfectant (pathogen killer) than iodine treatments. It is also stronger than, and chemically different from, free chlorine (familiar as household bleach. The biochemistry and microbiology communities generally prefer chlorine dioxide over chlorine or iodine for drinking water disinfection. For independent testing and research regarding the effectiveness of Aquamira, we recommend visiting

    In my research of hydatid tapeworms, I found that the most important methods of prevention are:

    1. Wash your hands with soap and warm water after contact with animals or animal feces (commonly canines and sheep) that may be infected.

    2. Wash your eating and drinking utensils after each use (or as often as necessary).

    3. Do not collect or eat wild fruits or vegetables picked directly from the ground. All wild-picked foods should be washed carefully or cooked before eating.

    These rules are just good common sense anytime you are traveling in the backcountry. Chemical water treatment and filtration are only part of the equation. For further information and tips regarding the prevention of E. Granulosus, we suggest contacting the health department or park ranger where you will be traveling.

    We hope you find this information helpful and thank you for your interest in McNett products.

    Best regards,

    Customer Service

    McNett Corporation

    1411 Meador Ave.

    Bellingham, WA 98229

    Tel: 360-671-2227 ext. 2717

    Fax: 360-671-4521

    paul johnson


    Locale: LazyBoy in my Den - miss the forest

    Here is the reply from the mfr’s of Steripen:

    Hi PJ,
    Thanks for your email.

    We have tested SteriPEN only against bacteria, viruses and the protozoa Cryptosporidium and Giardia. We have never tested against worm eggs – so unfortunately I can not give you a definitive answer with regard to UV treatment in this case. As to our pre-filter – we make no microbiological claims about it as it is really just intended to remove large particulates. The pore size is 4 microns by 4 microns square – it is a nylon material comparable to a coffee filter.

    While there is not a lot of literature on UV treatment of worm eggs, you may be interested to look at the following web site:

    When reading this keep in mind that the UV wavelengths emitted by SteriPEN are in the Mercury band with a primary energy output at 254 nanometers (in the UV-C range). Also, SteriPEN’s 1 liter treatment time is 90 seconds and generally delivers over 100 milijoules/ during this dose. Below is a quote from the above site:

    “The UVC lamp significantly inhibited the infectivity of taeniid eggs in rats. The Bonferroni/Dunn test for the mean number of cysts in the control group and the groups exposed to the UVC lamp was significant ( P<0.0001), except for the group at an exposure of 30 s (30 mJ/cm 2 at 254 nm). This means that the significant effect of the UVC lamp commences at an exposure duration of 90 s (90 mJ/cm 2 at 254 nm).”

    So, in a nutshell, I am sorry that I can not specifically point you to SteriPEN testing on worm eggs. And we probably will not do this testing in the future as it involves animal testing (we did animal testing for Crypto and Giardia because there was no alternative, however we decided we did not want to do animal testing again). But for whatever it is worth, the above referenced link does indicate that UV-C can have a disinfecting effect on worm eggs at the energy levels SteriPEN provides.

    Please let me know if you have any further questions.

    Best regards,


    Miles Maiden – CEO, CTO
    Hydro-Photon, Inc.
    P.O. Box 675
    262 Ellsworth Rd.
    Blue Hill, ME 04614

    Voice (207) 374-5800
    Fax (207) 374-5100
    Toll Free (888) 826-6234

    now, my turn again:

    the email reply stated that the steripen prefilter had a pore size “4 microns by 4 microns square – it is a nylon material comparable to a coffee filter.” based upon info in a prev. post re: Isle Royale & filter pore sizes, 25 microns was stated as the min. size for filtering out E. granulosus. Sounds like the steripen pre-filter should be able to handle the tape eggs.

    In case anyone is doesn’t already know & is interested, “taeniid” in the above email reply refers to a tapeworm family (Taeniidae) which includes Taenia saginata & Taenia solium, amongst others, which are the beef & pork tapeworms, respectively. Their eggs are quite a bit larger than E. granulosus (50%-100% larger if memory serves). The quoted portion of the email reply indicates Steripen is effective against the eggs at 90 seconds exposure UNDER A CONTROLLED TEST. Haven’t read the link yet, so i don’t know how the controlled test methodology compares to how one would use it in the field. Dr. J, or another real scientist, would be a better one than i to read and comment on the testing methodology referenced & factors that might affect similar performance during use in the field. Therefore, i intend to end my posts on this topic now.

    Mike Storesund


    Thanks for all the legwork on this. Great job!

    Dylan Skola
    BPL Member


    Locale: Southern California

    I like that McNett advised you to consult

    As for the steri-pen, the authors mention that the outer layer of the eggs of this and other parasitic worms are quite effective UV shields. So while they do begin to see effects at steri-pen doses (90-100 mJ/cm2) under controlled conditions, it only cut the the number of cysts by about 75 %. They didn’t see complete inactivation until 2430 mJ/cm2, which would require a much heavier and bulkier unit than the steri-pen.

    On the other hand, as long as the prefilter didn’t get punctured or bypassed, I would feel pretty good about its ability to remove the relatively large eggs before they got into the bottle.

    John S.
    BPL Member


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