Powell, WY


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‘The wolf tapeworm’

Although state and federal officials say it is rare, a tapeworm found in wolves could threaten humans in Park County, according to a local veterinarian. Although state and federal officials say it is rare, a tapeworm found in wolves could threaten humans in Park County, according to a local veterinarian. Photo courtesy Neale Blank

Powell veterinarian warns of problems that may be spread by wolves

A nasty tapeworm found in Alaskan wolves has turned up in Park County and has infected multiple elk and four dogs, according to a Powell veterinarian.

State and federal officials say the risk of infecting humans is low, but veterinarian Ray Acker, who owns and operates Big Horn Animal Care Center in Powell, said it behooves hunters and dog owners to take precautions to protect themselves and their pets from the parasite.

Echinococcosis granulosus (E. granulosus) can infect and kill humans, but there have been no reported cases of human fatalities in Wyoming.

Acker said he fears it is only a matter of time before the tapeworm’s cysts invade humans and potentially kill them.

E. granulosus tapeworm can infect all carnivores, but wolves and other canines are the primary host. “You could call it the wolf tapeworm,” Acker said.

“We always take any type of situation related to human safety and wildlife very seriously,” Dan Thompson, statewide supervisor of the large carnivore management section in Lander said in an email.

Hank Edwards, Wyoming Game & Fish Department laboratory supervisor in Laramie, said don’t panic, just be aware of the risk.

“I don’t know the prevalence in wolves, but certainly some carry it,” Edwards added. “It’s very, very rare that it infects people.”

Humans contract the hydatids (cysts) from E. granulosus. Hydatid disease in humans is difficult to diagnose and may require surgery to remove them. “It can be fatal,” Acker said.

Humans can be exposed to the eggs from canine feces or fur. From there the cysts take up residence in the human’s lungs or liver.

“It is a silent killer,” Acker said. Humans can unknowingly carry the cysts for 20 years until it becomes critical. When cysts rupture, the person enters anaphylactic shock and dies within 10 minutes, Acker said.

“Right now it’s rare for humans because it’s just emerging,” Acker said.

In Alaska, there have been 300 reported cases of hydatid disease in people since 1950. That is a result of canines, primarily wolves, contaminating the landscape with billions of E. granulosus eggs in their feces. The invisible eggs are ingested by wild and domestic grazing animals and occasionally by humans who release clouds of the eggs into the air by kicking the scat or examining the feces to see what the wolf had been eating, according to a December 2009 article in The Outdoorsman.

“This is not limited to wolves, and quite honestly we as an agency always stress safety precautions when dealing with wild game and/or fur bearers as it related to ectoparasites and other potential parasites,” Thompson said. “This topic seems to flare up every now and then, but it is still important that we (Wyoming Game & Fish Department) make sure people have the facts and are safely enjoying our outdoors. Long story short, the health risk is very low.”

In the last four or five months, it has been found in wild ungulates, but not domestic ungulates in Wyoming. It is not a problem for humans, but the possibility does exist, said State Veterinarian Jim Logan.

“It’s pretty rare as far as we know,” Logan said.

“In northwest Wyoming, hydatid cysts have been found in the lungs of a few moose and elk,” according to a 2010 Echinococcus granulosus in Wyoming fact sheet from the Game & Fish. “Where the parasite is found in wolves and wild ungulates, most public health agencies consider the public health risk to be very low.”

There have been no cases of E. granulosus in the Big Horn Mountains, but there are no wolves there, Acker said.

The definitive host for E. granulosus where they reach maturity and reproduce are canines and wild carnivores.

Wild or domesticated ungulates, such as elk or sheep and humans, serve as intermediate hosts where the parasite transitions between life stages. The larval stage results in the formation of hydatid cysts in intermediate hosts.

The eggs form inside the primary host. The eggs hatch into larva and migrate to the liver and lungs to form cysts. The predator, such as a canine, feeds on intermediate host prey and become the definitive or primary hosts, Acker said.

Stock on a national forest grazing allotment could pick up the cysts while grazing. Then the animals are brought back from the mountains to their pastures here. If the stock has the cysts in its lungs, they won’t gain weight.

Or, if the stock dies, predators or dogs eat the carcass and spread the disease. If numerous stock are infected it could have a significant financial impact on producers, Acker said.

Hunters should beware

In January a friend of Acker’s killed an elk in a Meeteetse hunt area. When the hunter field-dressed the elk, the lungs were loaded with cysts. Something attracted the dogs to the elk’s lungs, perhaps an odor from the cysts, and the dogs consumed the elk’s organs. He has wormed the dogs twice with praziquantel that kills E. granulosus in canines, Acker said.

Game & Fish sent the elk lung tissue samples to the Game & Fish lab in Laramie and the lab verified it as E. granulosus, Acker said.

“Do not feed uncooked meat or organs of deer, elk, moose or sheep to dogs,” said the fact sheet.

If a hunter notes hydatid cysts in their elk, they should not panic because the tapeworms must pass through a primary host like a dog first, Acker said.

Wolf hunters should be cautious handling their kill. Wear rubber gloves and take care handling feces and intestines, Acker said.

“Those hunting or trapping canids (mammals of the dog family) in Wyoming are encouraged to wear latex or rubber gloves when field dressing and skinning their animals. Additionally, wild game meat should always be cooked thoroughly,” said the fact sheet.

Taking the wolf pelt to a car wash and using the high-pressure hose to blow eggs off the fur is a handy precaution. Taxidermists should also use care, Acker said.

Watch for white segments around the rectums and in the dog’s stool. Initially the one-quarter by one-eighth inch segments will move slightly. Worm your dogs, Acker said.

Eggs can survive in excrement for up to one year. “I think they do well in the cold,” Acker said.

Dogs, with a propensity to roll in feces can collect the eggs on their coat and pass it on to their masters, Acker said.

Deworm dogs regularly. The best methods to prevent infection in humans are practicing good hygiene like wearing rubber or latex gloves and washing hands after handling dog excrement, said the fact sheet.

People should take precautions handling any wildlife. For example, people can contract bubonic plague from handling prairie dogs, Logan said.

Acker believes the disease has just reared its head among wildlife in this area. “We didn’t have it down here until they introduced these wolves,” he said.

In 1995/96 wolves from Alberta and British Columbia were re-introduced with 31 wolves in Yellowstone National Park and 35 in central Idaho. They were treated for parasites including, E. granulosus and it was well documented, Jimenez said.

“All wolves captured in Canada for relocation to Yellowstone National Park and central Idaho were treated for lice, roundworms and tapeworms before being released in Wyoming,” said the fact sheet.

Some people who dislike wolves returning to the region cite E. granulosus as another factor for their disdain for the canines. Acker admits to being anti-wolf, but he said if there are a lot of rabid skunks in the area they are eliminated in the interest of public safety.

“I’m anti-wolf here,” Acker said. “I think they belong where they came from.”

“People who are not real crazy about wolves see it as another reason to not be crazy about wolves,” said Mike Jimenez, U.S. Fish and Wildlife Service gray wolf recovery coordinator in Jackson. 

When Acker was a graduate student at Kansas State in Manhattan, he dissected two human livers from cadavers brimming with cysts. Action should be taken now, he said.

“Are we going to wait till somebody dies or try to keep somebody from dying?” Acker said.


  • posted by Barb Rupers

    November 10, 2014 7:46 pm

    "This is the first record of an E. granulosus G8 in Eurasia."
    Apparently Echinocossus granulosus G-8 is not a transplant to North America that came with reindeer brought to Alaska from Russia according to an article mentioned in the bibliography in the following link:
    This article also shows a map of the location of collected E granulossus cysts, most of the G-8 type, from Canadian ungulates. The probability that elk south of Canada would not also be carriers of this strain seem remote.

  • posted by Tim Kemery

    March 24, 2014 4:27 pm

    Both Dr.Acker and the "Rattler" have posted accurate summations of this growing Disease Focus. In Custer and Lemhi Counties in Idaho, a trained team of volunteers has been collecting fecal and intestinal samples from Primary host species such as fox, coyote, wolf, pine marten, and cyst samples (liver and lung) from ungulates. The collected samples are part of a Genotype Study being sponsored by Colorado State University. This spring the Genetic Strains identifying the Echinococcus tapeworms we have on our landscapes have been found to be of two Genotypes, G8 and G10. No Sheep Strain G1-G3 have been found in any of the samples analyzed. Since our counties in Idaho were the first to recieve introduced Canadian Grey Wolves we could also document that the E.g tapeworm hosts, both primary and intermediate were not domestic dog and sheep as had been previously suspected but using the DNA analysis we can track the G8/G10 right to the Canadian Grey wolves and their forebearers in Canada. Elderly populations of Domestic Sheep and Cattle have been screened for E.g Cyst presence since 2010 and no evidence of any have been found. Both the E.g Strains G8/G10 are Cervid Specific and are of Eurasian origin. These two strains are very agressively colonizing deer and elk in Custer and Lemhi Counties with the Liver and Lung Cysts estimated to be in as high as 70% of our Cervids. Both counties are considering severe containment strategies to attempt to break the disease cycle. Tragically the disease is Non-native Invasive. The prognosis is grim, both for residents of Idaho, Montana, and Wyoming and their Wildlife. The costs of Containment Protocols and Safety Standards will be high and must be borne by parties responsible. Mr. Jiminez is correct only superficially in stating that the Wolves introduced from Canada were treated for Tapeworms. The deception of his statement is glaring as the ONE dose of anthelmentic given the captured Canadian
    Grey Wolves was not at all adequate to clear the upper intestinal tracts of these canines. The proper dosing is 3 Doses of Praziquantal at 2 week intervals, with all feces cleaned daily from holding pens. We are happy to provide any interested persons with the Genotye Study results if they should so desire.
    Tim Kemery, E.g Field Sampling Coordinator Custer County, Idaho.

  • posted by Marty Godard

    March 21, 2014 9:46 pm

    I agree with Brad Campbell, Acker is only trying to stir up business, has always been that way, overpriced and not as good as the other local vets, That is putting it in a nut shell. Thanks MG

  • posted by anonymous

    March 21, 2014 9:05 am

    You rural anti-wildlife terrorists have lost. The wolves are back and elk, deer, nd moose will forever be managed by them.

  • posted by DebraKaye

    March 20, 2014 2:53 pm

    And now . . . the wolf lovers along with thinking they are biologist, scientists, and "actually" live with wolves . . . now consider themselves veterinarians also! Hoot hoot!!

  • posted by Barb

    March 20, 2014 2:06 pm

    The first wild ungulate tested and found to have E. glanulosus in Idaho was a mountain goat near Atlanta, ID east of Boise in 2006. Later that year it was detected in wolves which had been routinely tested since 1998.

  • posted by Rattler

    March 20, 2014 11:31 am

    Dewey doesn't know what he's talking about, first he cannot specifically identify the Echinococcosis granulosus g type in order to properly determine where it is from and where it has been. Why doesn't this parasite have a history in our DVM clinics across these three states until only recently? Why is the DVMs are just now connecting with other DVMS and sharing new info concerning this parasite?

    For example the Echinococcosis granulosus g type found in Idaho recently has been traced back to Reindeer brought to Alaska from Russia over 100 years ago, which by the way is found inCanadian wolves and was introduced here in Idaho/Wyoming.Montana with the wolves he mistakenly claims did not carry this parasite. YES they did as those wolves were improperly treatedfor the parasite and were not kept quarantined for the period of time required for followup treatments and testing in order insure the deworming of this Echinococcosis granulosus parasitehad been successful. Not only were wolves introduced , so was this Eurasian g type of Echinococcosis granulosus into our immediate environments.

    And then what do the environmentalists do, like Dewey Vanderhof? they lie, and they lie, and they lie, when all we're doing for now is warning hunters and rural residents how to take preventive measures in order that the highest of risk humans do not become infected with this disease, the children, playing yards, crawling around in carpets, where infected dogs have possibly been.

    In order to prevent transmission to dogs from intermediate hosts, dogs can be given anthelminthic vaccinations (Moro & Schantz 2009, Craig et al. 2007). In the case of intermediate hosts, especially sheep, these anthelminthic vaccinations do cause an antigenic response—meaning the body produces antibodi avinash response—however it does not prevent infection in the host(Moro & Schantz 2009 and Craig et al. 2007).
    Clean slaughter and high surveillance of potential intermediate host during slaughter is key in preventing the spread this cestode to its definitive host. It is vital to keep dogs and potential intermediate host as separated as possible to avoid perpetuating infection (Moro & Schantz 2009).According to mathematical modeling, vaccination of intermediate hosts, coupled with dosing definitive hosts with anthelminths is the most effect method for intervening with infection rates (Moro & Schantz 2009).

    It's time to stop listening to these third grade protect the wolf at all costs despicable liars like anti humanity Dewey.

  • posted by Brad Campbell

    March 20, 2014 10:54 am

    I think Acker is 'bomb thrower'. This article is full of questionable statements:
    " wolves in Big Horns..";

    (an elk hunter, hunting with his dogs?) "Something attracted the dogs to the elk’s lungs..";

    When Acker was a graduate student at Kansas State in Manhattan, he dissected two human livers from cadavers brimming with cysts. Action should be taken now, he said.(What does that have to do with today in Wyoming?);

    “Are we going to wait till somebody dies or try to keep somebody from dying?”

    I am sure the author,Gib Mathers, properly vetted all of these statements, right?

    I think perhaps there is a Vet in Powell trying to (literally) scare up some business...

  • posted by Kelly Tamburello DVM

    March 20, 2014 6:02 am

    This is an example of bad reporting. The main source of information is an openly biased individual who is not a wildlife veterinarian, a conservationist or an ecologist. None of these better qualified experts were consulted for their opinion. They talked to a local veterinarian who has treated a dog exposed to this parasite (through the negligence of the owner I might add-don't let your pets eat raw meat) and built an extensive article around his opinion. Get both sides of the story.

  • posted by anonymous

    March 19, 2014 7:52 pm

    These wolf haters are anti-wildlife terrorists. They are misinformed and ignorant to say the least. This tapeworm has always been native to Idaho and diseases are a natural party of nature whether you like it or not. This disease poses little threat to people of they use a little common sense. They are using this tapeworm to scare people and to demonize wolves. EG has been in Idaho for many years and it's not going anywhere. There is no way to get rid of it, so wolf haters will just have to accept that a little common sense goes a long way.

  • posted by Dewey

    March 19, 2014 12:38 pm

    The E. g. tapeworm has become a tightly focussed talking point of the rabid human wolf haters , as one of their many vitriolic reasons for disallowing grey wolves among us. As a vaild reason to be against wolves, it has been discounted or discharged by those who know what they are talking about, yet it persists among those who do not ...

    Be that as it may , the wolves brought here from Canada had no such parasite, at first . If they have it now, they acquired it locally from other canids or infected carcasses. Which means simply it was already here and already the health risk the wolf haters and wolf baiters are suddenly newly decrying. Plus ca change...

    By raising the issue and the hysteria about the tapeworm , the veterinarian calls into question his own professional credibility. The E. g. cyst issue is no greater nor any smaller now than pre-wolf Wyoming .

    I'm more concerned about the virus that causes humans to rant about such stuff...

  • posted by Robert Wood

    March 19, 2014 10:23 am

    Acker is under the delusion that if he points makes the case that "Wolves" are the only and sole cause of this organism being here, then there's a good case we could get rid of them. News flash, the organism was here long before the wolf came back. Eagles, coyotes, fox, cats etc all can carry this parasite, and routinely do. He's line: "“I’m anti-wolf here,” Acker said. “I think they belong where they came from.” pretty much tells where he's coming from.

  • posted by Randi Reiter

    March 19, 2014 9:25 am

    It seems to me, that being very careful and wearing rubber gloves when dressing game animals, would be a wise decision.

  • posted by Rick van Malssen

    March 19, 2014 4:10 am

    The german city of Stuttgart is the Echinococcosis multicularis hotspot in Europe and has been in decades. Multicularis is regarded as the big bad brother of Granulosis and is spread by red fox. It can cause death to infected humans and is much more dangerous than Granulosis. However even this desease is not regarded as a severe health risk by the german autorities. Very few people get actually infected and even less die from it. Don´t let hysterical myths take away common sense..

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