June 18, 2019

Emergence of Sylvatic Echinococcus granulosus as a Parasitic Zoonosis of Public Health Concern in an Indigenous Community in Canada

Within a remote Canadian Indigenous community, at least 11* of people had antibodies against Echinococcus granulosus and E. granulosus eggs were detected in 6* of environmentally collected canine fecal samples. Dog ownership, hunting, and trapping were not risk factors for seropositivity, suggesting that people are most likely exposed to E. granulosus through indirect contact with dog feces in the environment. In this situation, human exposure could be most effectively curtailed by preventing consumption of cervid viscera by free-roaming dogs.<<<Read More>>>

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Tiny Increments on Educating People About Echinococcus Granulosus in Maine

On February 20, 2013, I posted a press release sent out by the Maine Department of Inland Fisheries and Wildlife (MDIFW) about the discovery of echinococcus granulosus (E.G.) cysts found in moose. You can read that press release by clicking this link.

In addition to posting the press release, I also offered information about the disease to help readers obtain more knowledge and a better understanding of the real threats from this disease, frankly because I didn’t think the MDIFW press release contained enough information to help people make an honest assessment of the risks, which should become part of their decision making on outdoor excursions as well as proper care and prevention around the house.

With the help of a reader in finding it, the MDIFW posted some information on their website about E.G. While still inadequate, a small increment of changes were added to the original press release so positive actions are taking place.

To help readers better understand these tiny changes, I have posted the same information as can be found on the MDIFW website but took the liberty to highlight a few things there were added or omitted.

Echinococcus granulosus in Maine Moose

Over the last three years Inland Fisheries and Wildlife has been collaborating with the University of Maine Animal Health Lab in examining the presence of lungworms (Dictyocaulus spp.) in moose. Lungworms have been noted in moose that have been found dead in late winter with heavy winter tick loads and the combination of both parasites has been implicated as a cause of calf mortality.

This past fall, students once again increased sampling intensity of moose lungs from harvested animals. This led to the University of Maine-Animal Health Lab, finding Echinococcus granulosus (E.G.) cysts in some moose lungs. EG is a very small tapeworm that has a two part lifecycle; one in canids (coyotes/foxes/domestic dogs) and the second in moose. There are several known genotypes of this tapeworm, and genetic testing of the Maine tapeworms found that this EG is the northern, or least pathogenic, form. Although Echinococcus granulosus can infect humans, the form that is known to do so most often is the sheep-dog genotype. Finding the northern, wild-type form of EG in moose in Maine suggests that likely wild canids in Maine are infected and that possibly domestic dogs are infected as well, and that fact may allow for human exposure to this parasite. It is also very likely that we have coexisted with these tapeworms for years with no apparent problems having not actively looked for them prior to this work.

The adult tapeworm lives in the intestines of the canid host, while the larval form lives in the lungs or liver of an infected moose. Humans may become infected by [original press release included the word ‘ingesting’] eggs of the parasite, which can be picked up by contact with canid feces.

In conjunction with the Maine Center for Disease Control and Prevention and University of Maine Animal Health Lab/Cooperative extension, we recommend [original release used ‘the Department’] the following:

* Hunters avoid harvesting sick or injured animals. [This was added]
* Hunters and trappers should always wear rubber or latex gloves when field dressing animals.
* Wild game meat should be thoroughly cooked.
* People should avoid contact with dead wild animals
* People should avoid contact with carnivore feces [This was added]
* After consultation with your veterinarian, regularly deworm pets with a product that works on tapeworms [what is emboldened was added]
* Do not let domestic pets eat the organs from either hunter-harvested animals or from “road kill” animals [This entire warning was added]
* Practice good personal hygiene-wash hands and contaminated clothes, especially after handling animals or anything that could be contaminated with feces [entire warning was added]

On a positive note, it appears that the MDIFW is getting better educated about E.G. I will continue to send them information in hopes they are willing to gain better understanding and knowledge.

What hasn’t been brought out in either the original press release or this information posted on MDIFW’s website, is that if moose have these E.G. cysts, more than likely the whitetail deer, if they don’t have them now, soon will. As a matter of fact all ungulates are susceptible to E.G. This includes both wild and domestic ungulates.

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Hydatid Cyst Transmission and Growth

Hydatid Cyst Transmission and Growth
February 22, 2013
Author: Clayton H. Dethlefsen
Chairman and Executive Director
Western Predator Control Association

ISSUE: Can Hydatid Cysts cause the development of Hydatid Disease without the Transmission of E.g. Tapeworm Eggs through their expulsion in the fecal discharge of Canines?
 
DISCUSSION:

Key Point: Transmission from Hydatid Cysts that directly creates a new Cyst happens.  The only question is how this happens.
 
Ungulates with multiple Cyst including humans generally get them when Cyst that they already have burst or seep causing the Protoscolices (Hydatid Sand and/or the Cyst Fluid) to migrate to new location within the body.  Mostly these new cysts grow within the same body cavity or the same or immediately adjacent vital organs.

Hydatid Fluid contains tapeworm larva that have heads with connected tails that look much the same as swimming frog pollywogs. This fluid is often referred to as Hydatid Sand, which, if it gets into the circulation or respiratory system, can flow its way to new ungulate body locations.  Also, new cyst can form, if the initial Cyst was in the eye, in the eye socket, and if the initial Cyst was in bone marrow, new Cysts (because of the bone’s structure) are habitually confined to the bone’s cavity. Also, Cysts form in the tracheal and bronchial tubes, particularly where the Trachea branches into the Bronchi, or at a subcutaneous location if Sand from a burst or leaking cyst moves to these locations.
 
A good number of multiple cysts have developed from leakage of cystic fluid during surgical procedures including Puncture, Aspiration, Irrigation and Reaspiration (PAIR) and/or biopsy procedures used to determine if in fact a cyst is an Echinococcus granulosus (E.g.) product.  Most medical research on children and operations on these patients have been done in their brain cavity where PAIR and biopsy processes are extremely restricted. When secondary Cysts do form adjacent to vital organs or in adjacent brain locations, including those that form post operation, they cause a resurgence of nearly identical patient symptoms and problems. However, if the Sand migrates to other body locations the symptoms are usually somewhat different, as is their medical impact.

(Keep in mind that symptoms of Hydatid Cyst involvement are numerous, dependent on their location, and are similar to other vital organ maladies and/or infections such as tumors or bacterial infections which cause physical pressure increases and/or the destruction/decaying of organ tissue in circulation, respirations, digestion, etc. systems.)
 
The question of whether a person can get a cyst or cysts from puncturing them while field dressing game or butchering domestic animals comes up frequently.  In considering this we have to understand that viable (infectious) Hydatid Sand must get directly into a susceptible body cavity and/or vital organ, and the environment surrounding a cyst’s growth must nearly approximate the hermetically sealed or the surgical environment that is inherent with the formation of a new cyst, or a secondary cyst from an original leaking or bursting cyst.
 
We have positive medical records with photographs that show cysts occurring in human eyes, bone marrow and from external injection in subcutaneous tissue. We also know that cysts form internally in the vital organs and at the juncture of the trachea and bronchial transition. The cysts that occur at these non-normal locations form as a result of unusual circumstances, which generally do not include free movement of E.g. Eggs or Hydatid Sand through the normal process, i.e. the ungulate’s circulation system.
 
In the cases of Eye Cysts, Trachea and Bronchial Cysts and Subcutaneous Cysts, Cyst formation, normal and non-normal, has had only limited medical evaluation; therefore, no absolutely definitive formation-origin or cause has been confirmed. But several doctors and/or medical researchers believe that it is feasible that cysts in these locations can and do start with the direct-to-the-site, as opposed to by the normal circulatory system, introduction of E. g Eggs and/or Hydatid Sand from external sources and by external means.
 
The circulation system in the eye cavity where eye-cyst growth starts is primarily at the end of the circulation system, where very tiny capillaries distribute blood, and where the eye socket is warm and well lubricated. This fact and the fact that normal cyst formation is nearly always in the nearest and most easily accessible vital organ (fed by large veins and arteries) makes it highly improbable that eye cysts, for example, would be sourced through the ungulates digestive system with subsequent movement by blood-flow through capillaries. It is therefore more possible that initial and secondary eye cysts, as well as, subcutaneous, some bone marrow (reference broken bones) and bronchial and trachea cysts can and do occur as a result of more direct contact with and movement by outside physical transmission means.
 
Further, the normal development and passage of E.g. eggs (at this point they have developed into oncospheres) directs that they in sequence attach/seat themselves in major vital organs such as Liver, Kidney, Lungs and Heart, and as often in the case of children in the child’s Brain, and not further down the very constricted recesses of the circulation corridor. It is therefore most reasonable to conclude that cysts in the eye socket, bone marrow, and in subcutaneous tissue, as well as at the junction of the trachea and bronchi come by way of other transmission means.
 
From confirming medical data, specifically patient records and medical research, we find, conclusively, that cysts can develop and have developed from seeping or burst cysts, particularly when multiple cysts are found, and specifically without the introduction of new E.g. eggs (oncospheres). What is not clear, particularly with cyst that form from surgical procedures (where the body cavity is open to an external atmosphere) is how long Hydatid Sand will maintain a viable-infectious protoscolices loading or allow secondary cysts to grow after the patient’s surgery has concluded and the patient’s surgical site is closed.
 
During surgical procedures (a very sterile process in a maintained-sterile external environment) it is confirmed that Sand/Protoscolices exposure, because of the normal length of a surgical procedure, has been and is many hours. Hence it is reasonable and logical to conclude that (in the near-term) time of exposure of Hydatid Sand to an external environment seems to have little degradation or death effect which would prevent the formation of secondary cysts from Hydatid Sand.
 
Taking all this factually based information and using the “Reasonable Person” method of assessment, it is logical to assert that both primary and secondary Hydatid Cysts can form in ungulates if Hydatid Fluid flows, is inhaled/ingested or is injected from an external source (Elk, Deer, domestic sheep, cattle, etc.) into a human. Of course this Hydatid Fluid needs to move into open human and other ungulate orifices (mouths, bleeding cuts, nose, eye sockets, etc.) from where Hydatid fluid movement continues into susceptible body nodes through normal respiratory and/or bodily flow processes. Although rare, this action can and does happen.

It has been medically determined and medically reported that cysts can form in the respiratory system at and near the junction of the trachea and bronchial connection, in subcutaneous tissue through injection and direct contact with an open wound, and in a very wetted eye cavity. It is also a medical fact the E.g. eggs and subsequently oncospheres survive the passage through the hostile digestive environment in ungulates and that scolices/protoscolices are unharmed in the hostile canine and human digestive, circulatory, respiratory systems. If these conclusions were not factual the E.g. life cycle would have terminated centuries ago.
 
It has also been established that human hands, insects such as coprophagic flies and wasps, and wind are transporters of E.g. eggs from one point to another, and that ingestion, injection and inhalation are all primary means by which E.g. is transmitted. Thus, open access to Hydatid Sand with viable protoscolices from a burst or seeping cyst can also be transmitted by these means, and can henceforth be inhaled, ingested and/or injected into an ungulate with the result being the formation of new and/or secondary Hydatid Cyst.

CONCLUSION:

Fact–Humans get secondary Hydatid Cyst from internally located bursting and/or seeping Cysts.

Too, in the case of humans (hunters, butchers, etc.) it is not only feasible but it is truly possible for people to get Hydatid Cysts from an ungulate’s exposed Hydatid Cysts. This occurs when Hydatid Sand from a Cyst that has burst and/or is seeping comes into contacted with a human’s transmission means, and thereafter, this Hydatid Cyst Fluid (with viable Protoscolices) enters external body orifices. Transmission by hands or by having Sand surge or gush in some other manner into external orifices of the body are such means; hence, Cysts do not occur just from direct involvement with E.g. Eggs.

*Editor’s Note* – I presented this article to Dr. Delane Kritsky, noted parasitologist from Idaho State University. In particular I wanted clarification, once again, that hunters and trappers are not in danger of contracting hydatid disease simply by handling game animals that may have hydatid cysts. Here is Dr. Kritsky’s response:

Tom: It is true that if a cyst is ruptured within your body, it will result in new cysts developing. In addition, it is possible to inject material from a cyst from one host into a new host which will result in development of a cyst (or cysts) in the new host (This is often done to maintain E. granulosus and E. multilocularis in laboratory animals); injection is usually within the body cavity; this is one of the dangers associated with surgical removal of cysts — rupture and the release of the hydatid sand into the body cavity during surgery could result in new cyst development in the patient. However, there is no danger in becoming infected just by handling (or eating) a cyst that might have been present in a harvested animal. delane

 

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