Echinococcus multilocularis...small tapeworm, big problem

Echinococcus multilocularis is causing increasing concern in Ontario lately (amongst the few people who are aware of it, at least) as there’s evidence that it may have become established in the province. This parasite is a tapeworm harboured by canids (including both domestic dogs and wild ones like coyotes and foxes), and can cause serious disease in people. It’s an insidious problem since the incubation period in humans is many years, meaning it takes a long to realize that there’s a problem.

We don’t know the status of this parasite in the province but there’s enough evidence to be concerned and look into the issue further.

If you want to learn more about it, Dr. Andrew Peregrine’s recent seminar on the topic is a great start.

Canadian companion animal Ebola guidance

Concern (paranoia?) about Ebola in animals has died down lately, which is a good thing. In the meantime, guidelines have been developed to help handle potential animal Ebola-exposure issues, which is also a good thing.

While I’ve been slow posting them, Canadian guidance for management of companion animals potentially exposed to Ebola virus and for animal contacts of people potentially exposed to Ebola virus have been finalized. It was a lot of effort for something we’ll probably never use, but if we have to use them once, we’ll be very glad we went through the process. There were also benefits of getting various groups working together and thinking about the issues, so even if we don’t use them, the process was still valuable.

Part of the process also included a practice-run of certain procedures (done in collaboration with OMAFRA staff) using our dog Merlin as the "exposed" animal.  For more pictures, see the earlier W&G post or the recent University of Guelph press release.

For anyone who's curious, here they are:

Guidance for management of companion animals that have been exposed to a human with Ebola virus disease

Guidance regarding animal ownership and contact by individuals with potential Ebola virus exposure

 

Turtles and botulism

As reported on barfblog.com (with, as ever, an entertaining title: You see a cute turtle, I see a bug factory: Infant botulism from C. butyricum) a recent paper in the journal Epidemiology and Infection (Shelley et al. 2015) reports an unusual turtle-associated disease.

When we think about turtles and infections (especially infections of young kids), the first thing that comes to mind is Salmonella. That’s fair because it’s common and can be serious. However, like any animal, turtles can carry a range of microbes that can infect people. Apparently, we need to add the bacterium Clostridium butyricum to the list.

The paper describes botulism in two infants caused by this bacterium and related to turtle exposure. Botulism is classically caused by Clostridium botulinum, a bacterium that can produce some of the most potent neurotoxins known to science. However, a couple of other bacteria, including C. butyricum, can produce similar toxins and cause the same disease. Infants are highly susceptible to disease caused by ingestion of the bacterium, since it is able to grow in their gut because of their poorly developed intestinal bacterial flora. (In more mature individuals, botulism isn’t usually caused by ingestion of the bacterium itself. Rather, it's caused by eating food that contains the toxin that was produced when the bacterium was able to grow in the food).

The first case was an 11-day-old boy that was presented to a hospital with various neuromuscular abnormalities. As is common, he had to be put on a ventilator to help him breathe, but fortunately he made a full recovery over the next 10 days. Botulism was suspected early in the course of disease and he received antitoxin (antibodies against the toxins), which probably played a key role in his response. However, C. butryicum, not C. botulinum, was identified in his stool and it was confirmed that the bacterium was able to produce botulinum toxin E.

The second case was a child of about the same age admitted to hospital with breathing problems and a few other issues. Botulinum toxin E was found in his stool, and C. butyricum was isolated.

Investigation of possible sources of the bacterium ensued. Various food and environmental surfaces, plus feces from the parents, were tested. For the first boy, C. butyricum was isolated from his mother’s feces, as well as their turtle aquarium water, sediment and turtle food. The same batch of food from the pet store was negative, so the food was probably contaminated in the house.

The only positive location in the second child’s case was the turtle tank water in a relative’s house, not the child’s house. The relative had held and fed the baby.

These cases also led to a review of a case of C. butyricum botulism that had occurred in 2010. It was assumed to have been caused by honey ingestion, but further investigation revealed the presence of the same type of turtle (yellow-bellied terrapin) in the house.

This report doesn’t change anything in terms of recommendations regarding how to manage turtles, but is good to raise awareness. Turtles should not be in households that have kids less than 5 years of age, for multiple disease reasons. Infection of the second child via a relative who owned turtles raises concern about how pathogens can be spread indirectly from turtles to high-risk individuals. The relative was reported to have put her finger in the baby’s mouth to soothe him at one point, and that would be a logical source of exposure, highlighting the need for good hygiene practices after having contact with animals and their environments, especially high-risk species such as turtles.

As the authors conclude “Adherence to advice that reptiles, including terrapins, should not be kept as pets in homes where there are children aged <5 years, primarily to prevent salmonellosis, would also prevent cases of infant botulism associated with terrapins. The importance of hand washing after handling these pets also needs to be stressed, especially while visiting families with small children.”

Rabies warning for Kugluktuk residents

Residents of the Nunavut community of Kugluktuk are being warned about rabies in the area after a puppy that originated there was diagnosed with the disease in Saskatchewan. It’s not the first time rabies has been transported from a northern community in a dog, and this case should serve as yet another reminder of the risks of transporting diseases with animals (even within Canada). It looks like the puppy was "rescued" from the community and adopted in Saskatchewan. There are a lot of feral and semi-feral dogs in some northern areas, and various groups try to re-home them (with the best of intentions) to more southern communities.

The Deptartment of Health is warning Kugluktuk residents to stay away from dogs that behave strangely, and to make sure that they go to a health centre if bitten or scratched - good advice, although I’d expand it to staying away from all strange dogs, regardless of how they’re behaving.

There are two other important issues that this story brings up. One is vaccination of dogs, which can be difficult in communities that have limited access to veterinary care and/or where many dogs are "community dogs", without a defined owner to take responsibility for their care. Increasing vaccination is important to reduce the risk of rabies transmission, and there are efforts in many areas to do this. The other issue is adoption of animals. While rabies is now  fairly rare in Canada, this isn’t the first time this has happened, so groups that wish to remove animals from northern communities should ensure that the animals are properly vaccinated prior to transportation, and that new owners are warned about the increased risk of rabies (albeit still quite low). You can never 100% prevent disease transmission associated with animal movement, but making sure animals appear healthy before shipping, having good preventive medicine practices in place, and adequately tracking animals after they are shipped are important (and practical) measures to reduce the risk.

This case (and the location of Kugluktuk) can be found on wormsandgermsmap.com

 

Deworming wild and feral animals

I had a question the other day about roundworms in feral cats. Specifically, how do you deworm a group of cats that you don’t handle and may not be able to catch? There are a few possible approaches, from trapping and treating (oral or topical) to trying to get a dewormer into them via food. Neither is a great option in many situations, because you can't usually catch all the animals (and feral cats aren’t always the nicest to handle...), or they might not get the proper dose of drug if its given in food.

Baits are a convenient way to treat wild and feral animals, since they are easy to administer and can work quite well. Rabies vaccine baiting has been highly effective in wildlife, and a similar approach could be used for parasite control.

A recent study in Emerging Infectious Diseases (Page et al. 2014) shows the potential usefulness of dewormer baiting for control of the raccoon roundworm, Baylisascaris procyonis, in urban raccoons. The researchers made dewormer baits similar to those used for rabies vaccine, with marshmallow flavoring (don’t ask me why, but raccoons love marshmallows). They mixed a dewormer, pyrantel pamoate, with marshmallow crème, and sealed it in a hollow fishmeal polymer bait container. They then distributed baits in the vicinity of raccoon latrines in suburban Chicago and also tracked a set of untreated latrines. Fecal samples were collected from the environment before and after one year of monthly baiting.

Pre-treatment, B. procyonis was identified in 13% of samples, equally distributed between sites they subsequently baited and sites they did not bait (to act as controls).

After the one year baiting period, B. procyonis eggs were found in 21% of samples from the untreated control sites but only 3% of the treated sites.  That's a pretty dramatic (and statistically significant) difference.

This shows the potential impact of a relatively easy and cost-effective method to deworm raccoons, to reduce contamination of the environment and subsequent human exposure. It couldn’t be a one-shot deal, though. You’d never eradicate the parasite and raccoons will continue to be exposed, even if levels in latrines decrease. So, ongoing baiting would be needed to control the parasite and keep contamination down. That involves more effort and cost, but could be reasonable in high risk areas, such as parks with lots of raccoons and lots of human and pet traffic, or in other areas where elimination of latrines is not practical but there is a reasonable risk of human or domestic animal exposure.

It also raises questions about whether this might be an effective approach for feral cat colonies... stay tuned.

Human rabies incubation record

Records are meant to be broken, and rabies incubation period is no exception.

I’m often asked what the incubation period of rabies is in people. My general answer is "a long time, and we don’t really know how long it can be."

A report in the Annals of Neurology (Boland et al 2014) highlights this fact. It describes a case of rabies in a person who emigrated from Brazil to the US eight years before dying of rabies virus infection.

But, you might say, how do we know the incubation period was 8 years, since rabies is endemic in the US?  Good question, and this is where molecular epidemiology comes in handy:

  • The rabies virus isolated from the person was determined to be a Latin American dog rabies virus strain.
  • This strain isn’t present in the US. Furthermore, the man had not returned to Brazil (or even left Massachusetts) in the previous 8 years, nor had he had any contact with animals from outside the country.
  • It was also reported that the man had contact with a dog that was acting strangely prior to leaving Brazil. He killed the dog with a piece of wood and handled the body without gloves.

It’s a pretty convincing story and tops earlier well-documented lengthy incubation reports.

How and why rabies does this is unclear. It’s unusual for such a virus to lay low in the body for many years, and then cause rapidly fatal disease.

A major disadvantage to long incubation periods (for rabies or any other pathogen) is you can’t say “Well, that exposure occurred a few months/years ago, so there’s nothing to worry about." Avoiding exposure in the first place is always best.

On the up side, it’s generally believed that if someone gets post-exposure treatment at any time before signs of rabies develop, it can be effective. So, if somehow the potential exposure of this person had been identified, even years after the event but prior to the development of disease, and he'd been treated, he probably wouldn’t have gotten rabies. From a practical standpoint, though, would post-exposure treatment be prescribed, particularly given its cost?

In some ways it would make sense to query past animal exposure in people, especially those who have been in areas where canine rabies is highly endemic, and to treat anyone reporting a potential exposure. Yet, given the low incidence of imported rabies in people and the high cost of post-exposure treatment, it’s unlikely to be done.

 

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PetSmart employee worried about rabies after rat bite

As reported on WKTR NewsChannel 3 in Virginia:

“An employee at PetSmart [in Williamburg, Virginia] says she was bitten by a rat on display and is now worried she has rabies. She feels the store isn’t doing enough to help her find out if she has it.

Victoria Verbeeck says she was working at the Williamsburg store on Wednesday morning when a rat bit her finger. The rat had been acting oddly lately, she said, but she had handled it before. “It turned around and just chomped down on my finger,” she said. “I was more like that really just happened.”

Since it happened, she says PetSmart hasn’t been acting fast enough in helping to get the rat tested. With the holidays, she says she was told she’d have to wait until Monday to get help from PetSmart because corporate offices are closed until then.

A spokesperson from PetSmart says the company is taking the situation seriously. The health department is now overseeing the testing, according to the spokesperson. It’s not clear when the results will be available.”

What is the risk of rabies?

  • Exceptionally low. Although rodents can be infected with rabies (as can any mammal) they rarely carry it (likely because they are usually killed by whatever animal may have transmitted it to them in the first place).  However, low risk doesn’t mean zero, so the woman's concerns shouldn’t be dismissed out of hand.

Is rabies the only concern?

  • No. In fact, there are other more concerning issues, such as rat bite fever, a potentially nasty infection transmitted most commonly by (not surprisingly) rat bites.

Is the delay in testing that the woman has encountered a problem?

  • For rabies, no, particularly for a minor bite of an extremity. There’s time to get things sorted out and a few days isn’t a concern. The stress of the wait is the biggest problem.
  • The wait is most relevant in terms of other potential infections, since those develop quicker.

How will they figure out if rabies is a concern?

  • For some species (e.g. dogs, cats), it’s well defined. If the biter is still alive and normal 10 days after the bite, the animal could not have been shedding rabies virus at the time of the bite. Rules are less clear for other species and those are handled on a case-by-case basis, but given the very low risk of rabies in rats and the fact that rats are not a reservoir species, a quarantine period would probably be reasonable in a case like this. However, figuring out why the rat was acting "oddly" and if there is any evidence of a neurological disease component is important. If the rat has neurological abnormalities, immediate euthanasia and rabies testing would probably be recommended.

What’s the big issue here?

  • It amazes me that a company like this would not have a comprehensive and well-communicated bite policy. A well-thought-out and scrutinized policy should be available in all stores and readily accessible to all personnel. It takes time to get a good policy developed, but it’s worth it based on the amount of time that’s saved down the road after bites like this (which are probably quite common but not typically reported) and it can help prevent bite-related complications and concerns. Hopefully they actually have a good policy, but the fact that they have to wait until corporate offices are open to find it highlights a problem.

 

Imported and local Leishmania, Finland

I’ve written a fair bit about leishmaniasis in dogs lately, mainly in the context of potential risks from imported dogs. This parasitic infection is a concern because it can be serious and hard to treat, and also affects humans. Dogs are the main reservoir of Leishmania infantum, and it’s an important cause of disease in people in some regions.

The cases of leishmaniasis that we’re seeing in Canada (a relatively large and increasing number) have been associated with the dubious practice of importing dogs from endemic regions (e.g. Greece, Israel, Spain). One of the counter-arguments that comes up sometimes is “we don’t have any vectors of the parasite in Canada” (i.e. insects that can spread L. infantum from one animal to another, or from animal to person). However, the statement really should be “we don’t have any known vectors of teh parasite in Canada”. We can’t say with any certainty that none of the many insect types that are found here could transmit the parasite.

Further, while insects are the main concern as the natural vector and means of spreading the parasite widely (and, most concerning, into the wild canid populations that are abundant in Canada), they’re not the only concern.  As a bloodborne infection, Leishmania has many other potential routes of transmission between dogs and from dogs to people.

A Finnish study in the journal Acta Veterinaria Scandinavica (Karkamo et al 2014) illustrates some of these concerns. The study describes autochthonous (non-imported) leishmaniasis in dogs that had never left Finland or received a blood transfusion.

The short story:

  • A male dog (dog A) was sent to Spain for 6 months in 2009 as part of a breeding exchange. When he got back to Finland, he was diagnosed with leishmaniasis. He was ultimately euthanized.
  • Dog B was a Spanish dog that was in Finland as part of the exchange. He tested positive for Leishmania antibodies some time after his return to Spain. He had limited contact with the other dogs, but bred dog C in 2009.
  • In June 2010, dog A accidentally (well, accidentally from the breeder’s standpoint… I’m sure it was intentional in his mind) mated with dog D, but pregnancy either didn’t occur or was aborted.
  • In August 2011, dog A got into a fight with another male (dog E).
  • In 2012, dog E "accidentally" bred dog D (daughter of dog C).
  • In the spring of 2013, that male (dog E) got into a fight with a different female (dog C).
  • Dogs A, D and E were euthanized because of severe leishmaniosis that did not respond to treatment.

(If your head is spinning, there’s an easier-to-interpret figure in the paper.)

The assumption is that:

  • Dog A was infected in Spain and brought the parasite back to Finland.
  • Dog C was infected by breeding or fighting.
  • Dog D either got infected from its mother, mating with dog A or E, or fighting with dog E.
  • Dog E was infected by bites.

The authors’ conclusions also apply to non-Nordic regions:

It is likely that exotic diseases will be identified at increasing rates in Nordic countries in the future. Climate change may allow new insects to spread and survive in the Nordic countries and these insects may carry and spread new pathogens. Travelling of dogs has become more and more commonplace, which increases their risk of contracting and spreading diseases. The risk of spreading of the new vector-borne diseases within the Nordic countries has until now been considered low. Our findings show that this risk is not negligible and that leishmaniosis can spread in non-endemic areas without known vectors. In order to control this kind of risk, imported and breeding dogs should be tested for leishmaniosis before they leave their country of origin or before returning back home.

This case series only demonstrated risk to dogs, but the human aspect can’t be dismissed. We don’t know the true risks to humans from non-insect sources such as needlesticks, bites or contact with infected blood (e.g. contact of blood from an infected dog with an open sore). The risk is probably low but can’t be discounted. Stopping importation of infected dogs, and testing dogs coming from endemic areas would be a logical step to reduce the risks to dogs and people in non-endemic regions (although I won’t hold my breath).

Hazardous guinea pigs?

All animals pose some risk of infection to people, to one degree or another, but the risk varies a lot between animal species. I guess I’ve always considered guinea pigs to be relatively benig, with a few zoonotic disease concerns but with bites probably being the biggest risk.

I still think that’s true, but a couple of recent studies show that there are a few other things to to keep in mind.

A paper coming out in January’s edition of Emerging Infectious Diseases (Gruszynski et al., Streptococcus equi subsp zooepidemicus infections associated with guinea pigs) describes infections caused by a bacterium, commonly known as Strep zoo, that is typically found in horses, and occasionally in other species like dogs.

The first case was an adult in Virginia who started off with flu-like disease and then deteriorated, developing a serious systemic infection, shock and necrotizing fasciitis (flesh eating disease). Strep zoo was isolated from the patient's wounds. He spent several months in hospital and a rehabilitation centre, but survived.

The second patient was an elderly man, also from Virginia, who was related to the first patient. He went to the hospital with vague, predominantly flu-like signs, and developed pneumonia, septic shock and multi-organ failure. Strep zoo was isolated from his bloodstream. He was hospitalized for 18 days but survived.

Two infections by the same bug in people who have contact with each other certainly suggests there’s a common source or one infected the other.  But where do guinea pigs come into this story?

A relative of the first patient mentioned that he had recently purchased four guinea pigs, and that one had died shortly thereafter. The second patient had cleaned the guinea pig cage a couple of days before he became ill. So, it was logical to consider the guinea pigs as a possible source. Unfortunately the response was over-the-top. They euthanized all the guinea pigs and then tested them. Strep zoo was found in two of the guinea pigs, and the guinea pig and human isolates were indistinguishable. Presumably, the pigs were infected first and passed it to the two people through regular contact.

What does this mean, in the grand scheme of things?

  • Probably nothing major.
  • It’s a reminder that infections (including serious ones) can result from even normal contact with species we don’t often consider to be high risk.
  • It shows the importance of physicians querying pet contact.
  • It highlights the need for good basic infection control and hygiene practices around animals.

It also shows the common, but what I’d consider to be excessive, response that can occur when people finally do consider an animal source. It’s not clear whether the pigs were euthanized at the owner’s direction or whether public health pushed for it.

Euthanasia is the easy way out, since it removes any need to think about ongoing risk (euthanizing the animals before even testing them makes no sense at all to me). If the owner wasn’t going to take them back (or their interim caretaker wasn’t comfortable keeping them) and they were unwilling to re-home the pigs because of fear of infecting someone else, I can see how that decision would be made. It’s a stressful time when people are sick, and the fear of it happening again would be understandable.

However…

  • This bacterium is a rare cause of disease, and some people (e.g. horse owners) are exposed to it quite regularly.
  • It might only be present in the guinea pigs for a short period of time. We don’t know if they can be long-term carriers, and it’s possible they would get rid of it after a short period of time in a household (versus a stressful breeding colony or pet store environment).
  • Strep zoo-free guinea pigs would still pose some risk.

There’s never a simple answer for situations like this, and the full story would be interesting to know.

 

Are we too clean?

A recent episode of the popular TVO current affairs show "The Agenda with Steve Paikin" explores the topic of “Our Relationship with Cleanliness" - an informative, yet fun look at the topic of germs. Panelists (including yours truly) take a cultural, historical, psychological and sociological look at the microorganisms on us and around us - and how we respond to them (including some points on contact with pets, of course!). Worth watching!