September 19, 2019

Hydatid Disease: Man Has Gotten This Disease Since the Domestication of Dogs

Print Friendly, PDF & Email

Recently, Prof. Dr. P. R. Torgerson, PhD, VetMB, DipECVPH, Professor of Veterinary Epidemiology Vetsuisse Faculty, published an article titled, “Frequency Distributions of Helminths of Wolves in Kazakhstan.”

The Summary reads as follows:

Summary of “Frequency distributions of helminths of wolves in Kazakhstan.”

Between 2001 and 2008 a total of 41 wolves (Canis lupus) were necropsied in southern Kazakhstan and their intestinal parasite fauna evaluated. Of these animals 8 (19.5%) were infected with Echinococcus granulosus, 15 (36%) with Taenia spp, 13 (31.7%) with Dypilidium caninum, 5 (12.2%) with Mesocestoides lineatus, 15 (36.6%) with Toxocara canis, 16 (39%) with Toxascaris leonina, 8 (19.5%) with Trichuris vulpis, 9 (22%) with Macracanthorhynchus catulinus and 1 (2.4%) with Moniliformis moniliformis. All parasites had an aggregated distribution which followed a zero inflated or hurdle model. Although a small convenience sample of wolves, the results indicate a high prevalence of infection with E. granulosus. The mean abundance (1275 E. granulosus per wolf) was high with individual infected wolves carrying intensities of several thousand parasites. As wolves are common in Kazakhstan they may act as an important host in the transmission of this zoonotic parasite. The wolves were sampled from an area of Kazakhstan where there is a high prevalence of hydatid cysts in livestock and where echinococcosis has been observed in wild ungulates.

Affiliation

Kazakh State Veterinary Research Institute, Almaty, Kazakhstan.
Journal Details

This article was published in the following journal.

Name: Veterinary parasitology
ISSN: 1873-2550
Pages: 348-51
Links

PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/21962968
DOI: http://dx.doi.org/10.1016/j.vetpar.2011.09.004

Will Graves, author of “Wolves in Russia: Anxiety Through the Ages” and co-author of a new book soon to be released about wolves in the United States, having read Dr. Torgerson’s article, sent him an email seeking more information.

He wrote:

I am not a biologist but would like to exchange ideas with you about wolves. I am interested in Echinococcus granulosus and Neospora caninum.

Dr. Togerson replied to Will Graves, Torgerson says:

Dear Mr Graves
Thank you for your interest in our article. However I know little about wolves, other than there are lots of them in Kazakhstan. The primary interest was really in the parasites – especially Echinococcus granulosus. E. granulosus is a very serious zoonosis and in rural areas of Kazakhstan infects about 20% of dogs. It then transmits to people through close contact with dogs causing hydatid disease which is a large cystic lesion in your liver of lungs. The parasite naturally circulates between sheep and dogs. However the parasite almost certainly originated in wild life, probably circulating between wolves and wild ungulates. Man has been getting this disease ever since dogs were domesticated. I work with several scientists in Kazakhstan and the material for the manuscript was supplied by local hunters. In many areas wolves are considered a pest and a danger to livestock, especially as there are so many in Kazakhstan. (emboldening added)

Scientists that have knowledge of Echinococcus granulosus, i.e. Dr. Delane Kritsky, Dr. Valerius Geist, among others, have been trying to educate the public about where the real risk to humans comes from contracting human hydatid disease. Here we have Dr. Torgerson, in a region of the world where historically wolves have always been present, telling us that, “Man has been getting this disease ever since dogs were domesticated.”

The threat comes from free ranging dogs in rural settings that come in contact with the E.G. eggs through multiple sources. The dogs bring those eggs home with them running the risk of humans ingesting the tiny eggs.

But there exist some alarming figures that need to be shared. Dr. Torgerson says that of the 41 wolves he tested, 19.5%, or 8 of the wolves, tested positive for Echinococcus granulosus. As a result, Dr. Torgerson says that about 20% of domestic dogs become infected. Those numbers are startling enough. However, consider these numbers from Idaho.

According to Steve Alder of Idaho for Wildlife, in a recent email sent out, nearly 100% of recent necropsied wolves were infected with Echinococcus granulosus. If nearly 20% of infected wolf populations in Kazakhstan translates into about 20% of infected domestic dogs, what does this mean for Idaho?

This is a difficult thing to determine as certainly we don’t know the similarities in geography and population demographics of wolves and humans between Idaho and Kazakhstan. Nor do we know what kind of veterinary care exists between the two populations.

It is often said in this country that Echinococcus granulosus has never been a problem. That may be true but does the United States, particularly the lower 48 states, where denser human populations are exposed to wolf populations, have any real history of wolves and humans sharing the landscape?

This is why information that comes to us from areas around the world where that history is long can be helpful to us…..if only we would listen closely and learn. Dr. Torgerson says that hydatid disease in humans has existed since the domestication of dogs and yet people in this country refuse to except that fact, even though there now are thousands of wolves roaming the forests in parts of this nation.

The sooner doctors, scientists and canine lovers recognize this disease, along with many others carried by the wolf, the sooner we can all learn how best to protect ourselves, our children, pets and livestock. What’s wrong with that?

Share