Wolf Tapeworms Are a Serious Threat to Wildlife, Pets, and People
by Dr. Valerius Geist, Ph.D.
Professor Emeritus of Environmental Science, University of Calgary
Vancouver Island, British Columbia, Canada
Dear Friends,
When the news broke that hydatid disease had established itself in the NW of the United States, I quickly responded, stating some of the precautions hunters should take in the field. As a Canadian field biologist I was well instructed about hydatid disease in my training, which reinforced what I knew since childhood, because a relative of mine died of hydatid disease. Friendships during my career with medical people experienced with that disease reinforced what I knew. It’s nothing to fool around with!
I am consequently a bit concerned about recent statements that take a rather cavalier attitude towards the disease. The pro- and contra- machinations pertaining to wolves are of little concern here. What is important is that people living or recreating in areas with hydatid disease take precautions, and steps have to be undertaken to eradicate the disease.
To those supporting wolf conservation, let me make it clear: if wolves are going to survive in the NW, it will be wolves that are not infected with dog tapeworms. On this point, ludicrous as it may seem today to some, all parties can and should unite.
The more each party does its homework, the more likely this happy event will come to pass!
To reiterate briefly: because infected wolves, coyotes, dogs, and foxes (and also felines small and big, like house cats and mountain lions, and even raccoons) may carry dog tapeworm, or fox tapeworm or a number of related species of tapeworms, all of which are bad business, it is important that feces from carnivores is treated with great care –- as well as the handling of carcasses and skins of carnivores in affected areas.
Because the tiny eggs, liberated by the millions in carnivore feces, are dispersed even by tiny air currents, it is important for reasons of personal health not to poke or kick such feces. They will usually be dry. Disturbance can liberate clouds of tapeworm eggs, and these clouds of eggs will settle on your clothing, your exposed skin, in your sinuses and wind pipe, on your lips, and if you inhale through the mouth, in your oral cavity. If you lick your lips, the eggs will get into your oral cavity. When sinuses and windpipe clear themselves of inhaled particles with your sputum, the eggs will get into your mouth and be swallowed. If you touch the feces or even poke at them, chances are the cloud of tine eggs will also settle on your hands and may contaminate the food you handle or eat.
People with dogs are at risk because their dogs may feed (unbeknown to the owners) on carcasses or gut piles of big game infected with that disease, infecting themselves with dog tapeworm. These dogs will defecate in kennel and yards, spreading these tiny eggs. They will also lick their anus and fur, spreading the eggs into their fur. The eggs will cling to boots and and be carried indoors, where they float about until they settle down as dust. Now everybody is at risk of infection, especially toddlers crawling around on the floor. House cats can also be involved.
Hunters and ranching folks who keep or hunt with dogs in areas infected with hydatid disease are thus much more at risk than urban populations. The disease is silent, difficult to detect until very late, innocuous when the infection is light, provided the cysts that form are not interfering with vital functions, but lethal if they do, especially if cysts develop in the brain. Fox tapeworm infections are worse. Some new drugs can help contain the disease, but in many cases surgery is required. Unfortunately, the surgery can be very tricky.
To control the disease, we may have to undertake controlled burning of big game winter ranges to burn off the eggs. We should also consider targeting known wolf packs with medicated bait to purge them of tapeworms.
I wrote this much in an article currently in press and sent the manuscript to a colleague in Finland, Dr. Karloo Nygrén, a game biologist working on hydatid disease, asking him if I was correct or if I had exaggerated in any way or form.
Here is his reply:
Dear Val,
I am indeed working on Echinococcus granulosus even after my retirement 1.3.2010, because it appears to be spreading in my own home area, Karelia, both sides of the Fenno-Russian border. I am afraid it will not only affect our staple food and essential part of our heritage, moose, but also us directly. Hunters, dog owners, forest workers, berry and mushroom pickers will indeed be in danger. I agree with all you told in your paper; none of it is exaggeration.
So far, the largest hydatid disease outburst was in sixties-seventies in northernmost Lapland where it severely affected reindeer keeping people. It sincerely came with the wolves. I still remember dramatic articles of that period describing aerial extermination offensives against the wolves; never before or after that we have used aeroplanes with soldiers using “Suomi” submachine guns against wildlife! The wolf population was thinned out by all [available] means. I also have among memories from my younger days of a radio program where the local Game Chief (we have 15 such in Finland) gave instructions on how to shoot a wolf through the window — what gun and cartridges one should use and how close to the glass one should keep the barrel when the beast is watching through it.
After this [extermination] operation, much work and propaganda was needed to clean the reindeer herding dogs in and out. But it was done. Now, this new wolf wave has brought the parasite in again. Beginning from the reindeer area, findings gradually spread southwards along the eastern border.
Last spring, I was asked to obduce a moose found dead in the snow near Värtsilä, where we have an important border and customs station with about a million passengers annually coming and going. The moose was almost hairless (for a reason we were unable to confirm) but it had hydatid cysts in many organs, particularly lungs. I sampled the contents by injection needle and in a droplet placed on an objective glass, thousands of things like miniature human skulls with sharp teeth (my first impression!) were seen. This was the first case of E.granulosus for me. I have seen thousands of Taenia cysts in our moose after opening thousands of carcasses, but this was something else. And it was in my moose herd.
I quickly organized a sampling in that game management unit that the moose was found in and in the neighbourhood also; hunters gave me a total sample from their bag for last year. We did lungs only and used official state vets to make it officially very clear. It was shown that every 5th moose was carrying it in their lungs. Since liver seems to be among the very first organs normally affected, there may be an even higher prevalence than observed.
I told about our findings on a Swedish speaking radio program in Finland, and it also was heard in Sweden. The chief of Swedish hunters association, Dr.vet.med. Torsten Mörner commented and revealed that it has been found in Sweden also, after the re-appearance of wolves. Prof. Pjotr Danilov has started some kind of a program to find out the situation on his side of Karelia. Last March, a large wolf was killed by hunters near the border on Russian side. It had been seen several times on our side also and had caused fear only by its size. The weight measured soon after killing was 79 kilograms.We still seem to have some of that size alive.
It is no wonder why the Karelian Orthodox people living in villages feared wolves, killed them by all means but also considered dogs being not clean enough to be allowed inside human dwellings. Dogs in the village chapel, not to speak in monastries, almost caused a burning and re-building of the house. Thorough cleaning and religious rituals were needed anyway. One should also keep in mind that in an orthodox home, a set of hand washing equipment near the door was as essential as the icons on the opposite right-hand corner shelf. Before even greeting the people, the incoming person was supposed to wash his hands, dry them with a specially decorated towel, then make a cross sign with his right hand and bow towards the icon. Only then he was asked to step in further. Here, the homologies with other religious groups like Jews and Muslims automatically come in one’s mind. Do not eat pork (trichinosis danger!), do not drink or eat blood or you might die of bacterial poisons! Wash your hands to avoid hydatid disease!
Our hunters are just starting to understand what this all means. So too our veterinarians. The first concern of the lady dissecting our moose lungs was, “How should we publicize this without the risk that people start demanding all our wolves to be killed?”
Best wishes for 2010,
Kaarlo Nygrén
Game and Fisheries Research Institute
Ilomantsi Game Research Station
Ilomantsi, Finland
