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)
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.
Echinococcus
granulosus,
also called the
Hydatid worm
or Hyper Tape-worm,
is a cyclophyllidcestode 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.
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.
Echinococcus
multilocularis
is a
cyclophyllidcestode 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
Purdueveterinaryparasitologists 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.
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 granulosusseems 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
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. 2.
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.
5.
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."
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
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
ABSTRACT:
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)
