Wolf Parasites, Diseases, How To Avoid Them

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Worldwide Evolution of the Predator Disease Echinococcus granulosus and Its Impacts

The countries of Turkey, India, Pakistan, Afghanistan, Iraq and Iran lead the way in examining and treating Echinococcus granulosus. Additional countries are adding to the knowledge we now have about the devastation E. granulosus and E multilocularis are reaping. Hence, there are no doubts these diseases present a worldwide Health, Safety and Welfare problem. More importantly for us, they are creating a very local one....(full story)


The Wolf and the Spread of Disease by Nazarova

Wolves in the wild, seriously infected with the adult stage of cysticercosos by a tapeworm of the taenia family, are the sources of this parasitic invasion. It has been noted that where there aren't any wolves, the number of cysticerosis infected wild hooved animals is much less (Peterson, 1955). According to our data those wolves seriously infected with tapeworms (the source of larval parasites in feral hooved animals and in man) are found where their main food supply is hooved animals....(full story)





The genus Echinococcus includes six species of cyclophyllid tapeworms to date, of the family Taeniidae. Infection with Echinococcus results in hydatid disease, also known as echinococcosis.

In humans, this causes a disease called echinococcosis. Latency can be up to 50 years, and is mostly found in South and Central America, the Middle East, China, and the West of the U.S.A. (eg. Arizona, New Mexico and California).

Echinococcosis is a zoonosis, humans are dead-end hosts. The final hosts are predators - dogs, wolves, foxes, lions. The adult tapeworm lives in their intestine and delivers eggs that are excreted with the stool. The intermediate hosts are infected by ingesting eggs. Sheep, wild herbivores and rodents are the usual intermediate hosts, but humans can also be infected.

The egg hatches in the digestive system of the intermediate host, producing oncosphere larva. It penetrates the intestinal wall and is carried by bloodstream to liver, brain, lung or another organ. It settles there and turns into a bladder-like structure called hydatid cyst. From the inner lining of its wall, protoscolexes (i.e. scolexes with invaginated tissue layers) are budding and protruding to the fluid that is filling the cyst.

After the death of the normal intermediate host, its body can be eaten by carnivores suitable as final hosts. In their intestines, protoscolexes turn inside out, attach and give rise to adult tapeworms, completing the life cycle.

In humans, the cysts persist and grow for years. They are regularly found in the liver (and every possible organ: spleen, kidney, bone, brain, tongue and skin) and are asymptomatic until their growing size produces symptoms or are accidentally discovered. Disruption of the cysts (spontaneous or iatrogenic eg. liver biopsy) can be life threatening due to anaphylaxic shock.

Cysts are detected with ultrasound or CT. Antibodies can be detected with CF (complement fixation), ELISA, and various methods.



E. Granulosus

Echinococcus granulosus, also called the Hydatid worm or Hyper Tape-worm, is a cyclophyllid cestode that parasitizes the small intestine of canids as an adult, but which has important intermediate hosts such as livestock and humans, where it causes hydatid disease. The adult tapeworm is about 5 mm long and has three proglottids ("segments") when intact. Like all cyclophyllideans, E. granulosus has four suckers on its scolex ("head"), and E. granulosus also has a rostellum with hooks.

In canids, E. granulosus causes a typical tapeworm infection, and produces eggs that are passed with the dog's feces. Intermediate hosts include herbivores such as sheep, deer, moose, kangaroos, and wallabies, and any other organism (including humans) that ingests dog feces. In the intermediate host, eggs hatch into oncosphere larvae that travel through the blood and form hydatid cysts in the host's tissues. These cysts can grow to be the size of a softball or basketball, and may contain several smaller "balloons" inside the main cyst.  In the related worm Echinococcus multilocularis, the outer cyst is not present. If the outer cyst ruptures, new cysts can form at a different location in the body. Each smaller section contains several juvenile worms, and dogs may eat millions of them, resulting in very heavy infections. Hydatid cysts occur in organs like the liver, brain and lungs, not in subcutaneous tissue. Though this has never been tested experimentally, it is assumed that infected animals make easier prey for canids.

Symptoms can include liver enlargement, hooklets in sputum and possible anaphylactic shock when the immune system reacts to ruptured cysts. A cyst diagnosis with ultrasound, MRI, or immunoelectrophoresis.

Hydatid disease is treated with surgery, taking special care to leave the cyst intact so new cysts do not form, and mebendazole over a long period of time at low dosages. The best way to keep dogs from being infected is to prevent them from eating infected offal. The best way to avoid human infection is to avoid ingesting food or other substances contaminated with dog feces.


E. Multilocularis

Echinococcus multilocularis is a cyclophyllid cestode that, like Echinococcus granulosus, produces hydatid disease in many mammals, including rodents and humans. Unlike E. granulosus, E multilocularis produces many small cysts ("multilocular infection") that spread throughout the infected animal. When these cysts are ingested by a canid, usually by eating an infected rodent, it produces heavy infection with tapeworm adults.

The parasite Echinococcus multilocularis has become an increasing problem in urban areas. Since wild foxes are migrating to urban and periurban areas they maintain a closed contacts with human population (Vuitton, 2009[1]), consequently, the spreading of E.multilocularis seems to be increasing. Children, health workers, and domestic pets are affected by touching or handling wild foxes feces infected with the parasite. Even with the improvement of health in developed/industrialized countries, the prevalence of AE did not decrease (Vuitton, 2009[2]). On the contrary, incidents of AE have now also been registered in eastern European countries and sporadic incidences in other European countries (Vuitton, 2009[3]).

A study by Purdue veterinary parasitologists indicated that the disease is spreading throughout the American Midwest, where it was previously rare or nonexistent. Additionally, the disease has extended its range in Europe in the last few decades[1]. Still the infection is fairly rare. Between 1982 and 2000 559 cases were reported in entire Europe.

The Echinococcus multilocularis life cycle involves a definitive host and an intermediate host, each harboring different life stages of the parasite. Foxes or domestic canine are the definitive hosts for the adult stage of the parasite. The parasite attaches and resides in the mucosa of the intestines by hooks and suckers. It then produces hundreds of microscopic eggs, which are dispersed through the feces of foxes or carnivores (Vuitton, 2009[4]). Wild rodents such as mice serve as the intermediate host. Eggs ingested by rodents develop in the liver, lungs and other organs to form multilocular cysts. Humans could also become an intermediate host by handling infected animals or ingesting contaminated food, vegetable, and water. The life cycle is completed after a fox or canine consumes a rodent infected with cysts. Larvae within the cyst develop into adult tapeworms in the intestinal tract of the definitive host (Vuitton, 2009).


Neospora Abortion in Dairy Cattle

Steven L. Berry, DVM, MPVM; John H. Kirk, DVM, MPVM; Mark C. Thurmond, DVM, PhD

Department of Animal Science and
School of Veterinary Medicine, UC Davis

Neospora caninum is a coccidian protozoa that causes abortion in dairy cattle. Neospora has been found worldwide and is the most common cause of abortions on dairies in many areas including California. The organism was first identified i n 1988 as a cause of abortion in dogs and, shortly after; a Neospora–like organism was described as causing abortions in dairy cows. The organism causing abortion in cattle is now known to be the same species but a different strain as that ca using abortion in dogs....(the full story)



Neospora Caninum


Economic losses caused by this disease to the California dairy cattle industry has been estimated at $35,000,000 by the UC Davis School of Veterinary Medicine and would likely have a much higher cost if beef cattle losses were included in the estimate. Another study done to determine the rate of infection and transmission between wild and domestic animals found that 39% of wild gray wolves tested were infected with Neospora Caninum. It's known that canines can transmit...(the full story)

Hydatid Disease

Echinococcosis, also known as Hydatid Disease, is a potentially fatal parasitic disease caused by tapeworm of the genus Echinococcus - including Echinococcus granulosus and Echinococcus multilocularis. Echinococcosis has worldwide distribution and is endemic in certain areas of North America in increasing regularity. Echinococcus Granulosus is commonly spread by Canids to sheep, cattle, ungulates, and even to humans in which the infection is known as Hydatid Disease. Health workers have worked hard to eradicate this parasite in other countries and to educate people on how to avoid exposure. The video below explains the life cycle and how Echinococcus Granulosus is spread.

Health Organizations Explain Diseases

Health organizations worldwide discuss in detail the epidemiology, life cycle, spread, distribution, diagnosis, treatment, and the need to control Echinococcus; National Public Health Service, Health Protection Agency, Centers For Disease Control and Prevention, and the World Health Organization. The Canadian Medical Association Journal explains these parasites are more widespread in western Canada than is commonly known. An article in the Oxford Journals states, "For Canada and the United States the importance of the source of infection is paramount and the State of Alaska warns about these parasites in Alaska.

The Journal of Wildlife Diseases documents show that 62% to 63% of wolves tested in Idaho and Montana are infected with Echinococcus Granulosus. George Dovel has written in detail about Hydatid Disease, as have Dr. Val Geist and Mr. Will Graves regarding the dangers of Hydatid Disease being spread by wolves (which are definitive hosts of these parasites), but their warnings have been largely trivialized and ignored. The general public has a right to know what actions should be taken to help prevent the spread of wolves and Hydatid Disease causing worms, but state agencies have downplayed the issue. The implications for humans who contract Hydatid Disease are extreme, brain infections can require surgery.

Echinococcus Granulosus Life Cycle

The life cycle of these tapeworms requires a "definitive host" such as wolves, foxes, or dogs and an "intermediate host" deer, elk, domestic livestock, rodents, or even humans. The adult tapeworms which are attached to the intestines of a "definitive host" lay hundreds of eggs which are dispersed in the feces of the host animal across the countryside. Animals and rodents grazing near egg infested feces on the ground can unknowingly ingest the eggs which hatch in the "intermediate host" intestine. The hatched larvae penetrates the intestinal wall, gets into the circulatory system, and migrates to liver, lungs, heart, or even the brain, then the larvae develops a protective cyst and begins growing. Whenever an infected "intermediate host" is consumed by a carnivore "definitive host" the cysts from the organs of the "intermediate host" develop into adult tapeworms in the intestines of the new "definitive host" and the life cycle begins again.

How Wolves Can Spread Worms

Scientific reports indicate that 62% and 63% of the wolves tested in Idaho and Montana respectively between 2006 and 2008 were infected with the tapeworm Echinococcus granulosus. While it is unknown if the transplanted Canadian wolves (a known carrier) introduced the parasite, or if the parasite which was previously undetected in Idaho and Montana was brought in by migrating wolves, or if the parasite was present and undiscovered in resident prey species. What is known is that even though the USFWS claim they wormed all the imported wolves before release, wolves in Idaho and Montana now have a high infection rate of Echinococcus granulosus and some prey species such as deer, elk, and goats in Idaho and Montana are now known to be infected with Echinococcus granulosus, so the complete life cycle of Echinococcus granulosus seems to be occurring in Idaho and Montana.

Wolves are the widest ranging Canids in North America plus wolves in the western US are known to have a high rate of infection with Echinococcus granulosus. Recently a Montana wolf is known to have traveled more than 1000 miles through five states in a 6 month period. If this wolf was an infected wolf it spread infected feces across 5 states in only about 6 months. Wild animals and livestock grazing in areas where wolves may have left egg infested feces can become infected. Dogs, coyotes, foxes, or other wolves who by nature commonly sniff another Canids feces may become infected if they unknowingly sniff an egg infested wolf feces.

Once infected, dogs could spread eggs onto themselves by naturally licking themselves or they could spread eggs when they defecate in yards or gardens. People who own pets, or people who live, work, recreate, or gather wild foods such as huckleberries or mushrooms have a higher risk of infection. Hunters, trappers, taxidermists, wildlife professionals, veterinarians, ranchers, farmers, young children or anyone who often handles animals bear a higher risk of infection.

Hydatid Disease affects people all over the world, especially those who work or live with animals. Humans can get infected by eating food or drinking water which is contaminated. Adults or children can become infected by handling animals without practicing a high level of hygiene during and after contact. Hand to mouth transmission can occur after handling (petting) an infected canine or touching anything where an infected canine has been laying such as indoor flooring. (Canines naturally lick their anus and lick other parts of their bodies while grooming, potentially spreading eggs onto their fur in unknown quantities.) Humans can also infect each other through a lack of hygiene (not washing hands) during food preparation.


Echinococcus granulosus (Cestoda: Taeniidae) infections and moose – wolf population dynamics in southwestern Quebec

François Messier, Manfred E. Rau, Marilyn A. McNeill

Canadian Journal of Zoology, 1989, 67:(1) 216-219, 10.1139/z89-029


The prevalence, mean number, and mean total weight of Echinococcus granulosus cysts in the lungs of moose increased with moose density in southwestern Quebec. Such responses in the level of infection were documented in areas of 0.17, 0.23, and 0.37 moose/km2. The increase of E. granulosus infection in moose was attributed to higher densities of wolves, the definitive host of this parasite, as well as an accompanying increase in the rate of wolf predation upon moose. The aggregated distribution of this parasite within the moose population is considered to reflect the highly heterogeneous use of space by wolves and the consequent aggregated distribution of parasite eggs within the environment. A possible regulatory effect of E. granulosus infections on moose numbers is discussed.




Take Precautions Against Wolf Worms

Wolves are migrating into neighboring states from Idaho and Montana, should wolf colonization into new areas and overall wolf numbers be controlled to lessen the chances of spreading diseases until more is known about the impacts these diseases could have in the western United States?

You can decide for yourself, but it appears that warnings about Hydatid Disease are definitely worthy of serious consideration . If you live near areas inhabited by infected wolves in the West or infected foxes in the Midwest, you may want to practice precautionary measures to minimize your exposure to parasites.

1.   Wear plastic gloves whenever handling wild game, especially carnivores.
 Avoid exposure to infected feces, do not touch, kick, or disturb carnivore feces.
3.   Consider affects of livestock grazing on the ground in areas inhabited by infected wolves or foxes.

4.   Do not let pets roam freely in areas known to be inhabited by infected wolves or foxes.

 Obtain and use an effective dog wormer on dogs that may have been exposed to wolf or fox feces.
6.   Cook wild game well before eating.

7.   Do not collect or eat wild fruits or vegetables picked directly from the ground.
8.   Wild-picked foods should always be washed carefully or cooked before eating.
9.   Fence in gardens to keep out wild animals and pets.

10.  Do not allow pets to eat wild animal or livestock offal.
11.  Keep children from touching pets which could be infected, children put their hands in their mouths.
12.  Use caution allowing pets in your home. (pets which could have been exposed to wolf feces)

Hopefully wildlife managers will take measures to protect the public's safety and health from the dangers of these parasites. It seems irresponsible to encourage colonization of new areas by wolves which are known to come from infected areas. It would seem that everything should be done to prevent the spread of a known parasite that has a history of serious health consequences in humans and other animals.


Will Graves' Book

Mr. Will Graves the author of “Wolves in Russia: Anxiety Through the Ages“, has studied wolves for many years. He has traveled to Russia and surrounding nations to gather information, including historic documents, etc., to learn more about wolves, their diseases and the impact these animals have had on humans for centuries. This is the basis of his book.  (source)


In a letter, dated October 3, 1993, Will Graves  wrote a letter to Ed Bangs, US Fish and Wildlife Service (USFWS) Project Leader for the introduction of the Canadian Gray, in Helena, MT.  Graves concerns, outlined in the letter, while very valid, were ignored, not only by Ed Bangs but also by the USFWS. Everyone should read Graves' letter.  It is very important.

Quote from Mr. Graves:

"If wolves are planted in YNP and in Idaho, I believe the wolves will undoubtedly play a role in the epizootiology and epidemiology of rabies. The wolf has played an important role, or perhaps a major role, as a source of rabies for humans in Russia, Asia, and the former USSR. From 1976 to 1980 a wolf bite was the cause of rabies in 3.5% of human cases in the Uzbek, Kazakh, and Georgian SSRs and in several areas of the RSFSR. Thirty cases of wolf rabies and 36 attacks on humans by wolves were registered in 1975-78 only in the European area of RSFSR. In the Ukraine, wolf rabies constituted .8% of all cases of rabies in wildlife in 1964 to 1978. The incidence of wolf rabies increased six fold between 1977 & 1979, the epizootic significance of the wolf has been shown in the Siberian part of the former USSR. Between 1950 and 1977 a total of 8.7% of rabies cases in the Eastern Baikal region were caused by wolf bites. In the Aktyubinsk Region of Kazakhstan, of 54 wolves examined from 1972 to 1978, 17 or 31.5% tested positive for rabies. During this period, 50 people were attacked by wolves and 33 suffered bites by rabid wolves. This shows that healthy wolves also attack and bite humans. Recent Russian research states that as the numbers of hybrid wolves increases, the likelihood of a healthy hybrid wolf attacking humans also increases, as the wolves lose their fear of humans.
Wolves not only have and carry rabies, but also have carried foot and mouth disease and anthrax. Wolves in Russia are reported to carry over 50 types of worms and parasites, including echinococcus, cysticercus and the trichinellidae family. Prior to planting wolves into YNP and into Idaho, I respectfully request a detailed study be made on the potential impact wolves will have in regard to carry, harboring, and spreading diseases." 
(source) letter





Warning To Environmental Quality Council

I do not understand how anyone in the US could say that Hydatid Disease does not pose a significant threat to humans. It is difficult to detect this disease in humans, and it may go undetected for an extended period of time, even twenty plus years. Late detection increases the risk of serious consequences or even death. Hydatid eggs can survive severe cold temperatures, and note that they can be carried in water. Research needs to be carried out in both of these areas.


The parasite Neospora Caninum causes abortion in cattle and is carried by dogs and coyotes. It has not been determined if wolves are the definitive hosts of this parasite. I personally suspect that wolves may also carry and spread N. Caninum. I believe research needs to be done in this area...(full story)


Dr. Val Geist

Professional Biologist, Professor Emeritus of Environmental Science, University of Calgary, in an e-mail to a concerned citizen, had this to say:


"It is well known that domestic dogs play a very large risk factor in hydatid disease. Unlike in Northern Canada or Alaska, in the West one is dealing with much greater densities of people, dogs and carrier species such as deer or elk. High incidents of the parasite in wolves and coyotes and a high infestation rate with cysts in lungs and liver of deer and elk, put at risk the ranching, farming and rural communities. In winter time deer and elk will frequently be found on ranches close to communities. Dogs from ranches, farms and hamlets will have access to winter killed carcasses of deer and elk as well as to offal left in the field during the hunting season. Once infected with dog tape worm, the ranch and house dogs will contaminate the yard, porches, living rooms etc with hydatid eggs. There is no escape from this! Ten to twenty years down the road, hydatid disease will raise its head, in particular in persons who as toddlers crawled over floors walked over by people and dogs carrying in hydatid eggs from the outside. Please inform yourself what this is likely to mean in terms of prognosis, suffering and costs!"


Dr Geist closed his e-mail to the concerned citizen as follows:


"Wolves have been exterminated from lived in landscapes universally because they, or their diseases, posed a serious threat to affected people, livestock and wild life. The lessons from history are that we can at best live with wolves if such are relatively few, the abundance of natural prey is high, and the risk from diseases non-existent."




Transmission Of Neospora Caninum

Between Wild And Domestic Animals

L. F. P. Gondim, M. M. McAllister, N. E. Mateus-Pinilla*, W. C. Pitt, L. D. Mech, and M. E. Nelson


Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Illinois, 2001 South Lincoln Avenue, Urbana, Illinois 61802. e-mail: pita@ufba.br



To determine whether deer can transmit Neospora caninum, brains of naturally infected white-tailed deer (Odocoileusvirginianus) were fed to 4 dogs; 2 of these dogs shed oocysts. Oocysts from 1 of the dogs were tested by polymerase chain reaction and found to be positive for N. caninum and negative for Hammondia heydorni. The internal transcribed spacer 1 sequence of the new strain (designated NC-deer1) was identical to N. caninum from domestic animals, indicating that N. caninum is transmitted between wild and domestic animals, often enough to prevent divergent evolution of isolated populations of the parasite. NC-deer1 oocysts were administered to a calf that developed a high antibody titer, providing evidence that N. caninum from wildlife can infect cattle. In addition, N. caninum antibody seroprevalence was detected in 64/164 (39%) free-ranging gray wolves (Canis lupus), 12/113 (11%) coyotes (Canis latrans), 50/193 (26%) white-tailed deer, and 8/61 (13%) moose (Alces alces). These data are consistent with a sylvatic transmission cycle of N. caninum between cervids and canids. We speculate that hunting by humans favors the transmission of N. caninum from deer to canids, because deer carcasses are usually eviscerated in the field. Infection of canids in turn increases the risk of transmitting the parasite to domestic livestock....(the full story)






Worldwide Evolution of E granulosus......http://www.wpcamt.org/apps/blog/show/5934559-informative-article-ii-of-xi-disease-news-

Warning To Environmental Council.........http://graywolfnews.com/pdf/Graves_CommentsToEQC-4.pdf

Hydatid Disease...................................http://en.wikipedia.org/wiki/Hydatid_disease
Echinococcus granulosus......................
Echinococcus multilocularis...................
World Health Organization.....................http://www.who.int/zoonoses/diseases/echinococcosis/en/

Canadian Journal of Zoology..................http://www.nrcresearchpress.com/doi/abs/10.1139/z89-029

Journal of Wildlife Disease.....................http://www.jwildlifedis.org/cgi/content/abstract/45/4/1208
Center For Disease Control....................http://www.dpd.cdc.gov/dpdx/html/Echinococcosis.htm
Health Protection Agency
Canadian Medical Association...............http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1822812/?page=1

Overview, Transmission, Prevention
........http://www.wales.nhs.uk/sites3/Documents/719/Hydatid disease 2007.pdf

17 Cases Diagnosed in Winnipeg...........http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2094814/
42 Cases Diagnosed in Edmonton.........http://www.biomedcentral.com/1471-2334/5/34
337 Cases in United States & Canada
Amerian College of Chest Physicians

Wolves And The Spread Of Disease......http://wolvesinrussia.com/
Distribution In Northwestern Canada......
Hydatid Disease In Boreal Regions........
Outdoor Warning..................................


Synopsis Hydatid Disease....................http://westinstenv.org/wildpeop/2010/02/07/synopsis-of-wolf-borne-hydatid-disease/
Hydatid Disease Medications................
Surgical Treatment Hydatid Disease

Implications For Vaccine Development...http://www.jimmunol.org/cgi/content/abstract/181/10/6679
Brain Hydatid Cyst Neuro-Surgery

Neospora Abortion in Dairy Cattle..........http://www.vetmed.ucdavis.edu/vetext/INF-DA/INF-DA_NEOSPORA.HTML

Transmission Of Neospora Caninum......http://www.klamathbasincrisis.org/wolves/neosporatrans.pdf



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