Effective tomorrow, the US Centers for Disease Control and Prevention (CDC) has suspended importation of dogs to the US that:

  • are from Egypt, or
  • originated in Egypt and have been in another country for less than 6 months.

This is being done because of multiple cases of rabies in imported dogs specifically from Egypt over the past few years (including some with falsified vaccination certificates). Despite rules for high risk countries like Egypt, rabid dogs can still slip into the country because of ineffective vaccines, fraudulent health records and the potentially long incubation period of this disease.

Banning dogs travelling directly from Egypt will be straightforward. Banning dogs that have recently been in Egypt will be more of a challenge. For example, if they go to another country considered high risk for canine rabies, they’d need to get a new rabies vaccination certificate (hopefully along with a valid vaccine!) from that country, otherwise the Egyptian certificate would give away their recent origin. It’s a somewhat surprising step since regulation and restriction of dog importation tends to be low priority, but it’s good to see.

Let’s see if other countries (yes, I’m talking about you Canada) follow suit, since a large number of dogs are imported into Canada from Egypt every year.

When I talk to veterinary and public health audiences about zoonotic diseases, I often talk about rat bite fever because it highlights some common issues that are important to keep in mind.

Usually, I start by presenting a case of a child with a fever and rash.

Then, I mention that someone finally asked about pets and they reported a rat bite.

Then, I say “what does the kid probably have?

  • And I get… blank stares 95% of the time.

Then I say “the kid had a rat biteand has a fever… what is it?

  • More blank stares (some are probably asleep, admittedly).

Then I say “rat bite fever [pause]… seriously, that’s the name of the disease.”

  • Still some blank stares (and the odd snore).

Beyond showing the limited awareness of this disease, the cases in which I get involved have a few common themes:

  • The bite is rarely reported initially. It’s not usually until the person gets referred to a specialist that someone asks about pet contact. “Has your child had any animal contact?” is an easy question to ask, but it rarely gets asked, in my experience. So, the opportunity for early diagnosis is missed.
  • The important issue of zoonotic disease risk and risk acceptance that go along with pet ownership or animal contact. Pretty much all rats harbour the bacterium that causes rat bite fever (Streptobacillus moniliformis), so every rat poses some degree of risk. The risk can lowered with good handling practices (to avoid bites) and proper bite first aid. Rat ownership can still be relatively low risk with some common sense, but it’s never zero.  People handling or owning rats need to be aware of the risk and how to mitigate it.

Anyway, that’s a long lead-in to a recent paper on rat bite fever in Canada (Hryciw et al, Can Commun Dis Rep 2018).

It’s a recap of 11 cases on Vancouver Island between 2010 and 2016

  • All affected people had pretty typical disease: fever and one or more of muscle pain, rash, joint pain, swollen joints or vomiting.
  • Everyone recovered, but seven patients were hospitalized.
  • Both bites and scratches were implicated as the source. Scratches are a potential source if they become inoculated with rat saliva at the same time.
  • All reported rat contacts were from pet rats.
  • Not much more about the rats or bites was reported.

There wasn’t too much remarkable in the paper overall, but it’s another good reminder about this disease and the need to report (patients) and query (healthcare providers) history of pet contact when someone is sick.

More information about rat bite fever can be found on the Worms & Germs Resources – Pets page.

Rabies is “almost always” transmitted by bites and “almost invariably” fatal once disease develops in a person or animal. We use a lot of these kinds of disclaimers with infectious diseases, which can be frustrating, but it’s necessary because exceptional (strange) things occasionally occur.

A report in an upcoming edition of Emerging Infectious Diseases (Zhao et al). describes an unusual case of rabies in a man from China.

The man was from a village in Jiangsu province, China, where canine rabies is endemic. His son was bitten by a stray dog, which is absolutely considered a potential rabies exposure unless the dog is caught for quarantine or testing. Family members provided wound care, which is important, but as part of this treatment the man in question tried to suck “toxic blood” from his son’s wounds.

Neighbours killed and buried the dog, so it couldn’t be tested for rabies, but the son got appropriate medical care and received post-exposure prophylaxis (PEP). The physician also recommended PEP to the father, because of the potential that he could have been exposed to rabies virus in saliva from the dog that had been deposited in the wound. However, he declined, in part because of cost and because of his belief that he had spat out all the blood.

Approximately a month later, the man developed signs of rabies, and died the day after he was hospitalized. His son was fine.

While control of rabies in areas where it is widespread in the dog population is challenging, preventing rabies in people is actually straightforward. Rabies PEP is “almost always” effective (another waffly term, but failure of properly administered PEP is incredibly rare, if it even occurs). But things fall apart when there is poor education (e.g. the bite victim or healthcare providers not understanding the need for treatment), lack of access to treatment or economic barriers. Here, two of these were involved in this man’s death: while healthcare providers recognized the risk and made the appropriate recommendation, the man declined because of a lack of understanding of the risk and because of cost concerns. These factors resulted in his death as much as the dog itself did.

Happy Easter from Finnegan and Merlin (well… maybe not so much Finnegan).

Nothing has changed about Echinococcus multilocularis (the fox tapeworm) in the past couple of months, but my phone is ringing off the hook following another round of media reports about this parasite. Here’s a recap of the issues:

  • Echinococcus multilocularis is a small tapeworm normally found in the intestinal tract of wild canids (e.g. coyotes, foxes) and sometimes dogs. For these animals, having this worm in the gut doesn’t cause a problem. The main concern is when something (or someone) ingests tapeworm eggs that are passed in feces of these canids.  This can result in a condition called alveolar echinococcosis (AE), in which tumour-like parasitic cysts can develop in other parts of the body, particularly in the liver.
  • In the normal (wildlife) life cycle of this tapeworm, wild canids shed eggs in their feces which are eaten by small rodents, that then develop AE. When a canid eats an infected rodent, the parasite grows into its adult stage in the canid’s gut and produces more eggs, and the cycle continues.  While that’s bad for the rodents, the bigger problem is that this “intermediate host” stage can occur in more than rodents… including dogs and people.
  • Alveolar echinococcosis has been diagnosed in a small number of Ontario dogs (with little to no travel history) since 2012, raising questions about how they got infected. The concern was that this parasite had become established in our wild canid population, which presents an ongoing risk to people and other animals, and is very hard to control.
  • Human cases in Canada are rare but are being found and may be underdiagnosed.  Since AE is a very nasty disease, and very difficult to treat, we’re inherently cautious.

The recent news stories picked up on a study published earlier this year in Emerging Infectious Diseases (Kotwa et al 2019), where an astounding 23% of wild canids in Southern Ontario were found to be shedding Echinococcus multilocularis. 

What’s the risk to dogs in Ontario?

  • We don’t know. I realize that’s not comforting but it’s the honest answer. We should know a lot more in the next few months as we test samples from pet dogs in the highest risk areas. Until then, it’s hard to say much with confidence.

What should dog owners do?

There are two main approaches to prevention: decreasing the risk of exposure and prophylactic treatment.

We can treat dogs for tapeworms, but this isn’t usually part of routine deworming protocols, so only a small percentage of dogs are treated on a regular basis. I’ve been treating my dog with praziquantel monthly for the past couple of years, since emergence of the parasite was identified, because we’re in a higher risk area and he will eat anything. We live in the country and have a lot of coyotes around. If the parasite is here, it’s quite plausible he would be exposed.

The risk is much lower (or non-existent, potentially) in other regions, and dogs that have less outdoor access are much lower risk. Quantifying that risk is the challenge.

Ultimately, whether or not to treat a dog prophylactically is a case-by-case decision, based on the dog’s risk factors (and the owner’s risk aversion).

More information about Echinococcus multilocularis can be found on the Worms & Germs Resources – Pets page. Also check out emultiontario.com and the updated infographic from the Ontario Animal Health Network.  We’ll provide updates as more information about this parasite becomes available.

A recent presentation at ECCMID (European Congress of Clinical Microbiology and Infectious Diseases) in Amsterdam described a series of linezolid-resistant enterococci in dogs and cats in the UK. I’m only able to get information from media reports, so details are limited (and potentially lost in translation); however, it’s an interesting story. It’s unsurprising in many ways, but highlights some important issues.

Linezolid is an antibiotic that’s typically used in human medicine for infections caused by multidrug-resistant Gram-positive bacteria such as staphylococci (including MRSA) and enterococci. It’s rarely used in veterinary medicine, but has been used in dogs and cats for the same types of infections. Because it’s one of few options for treatment of MRSA in people, it’s an important drug, and resistance is a significant concern.

The UK story involves a cluster of infections at one veterinary clinic. Enterococci that were resistant to linezolid were found in two cats and one dog. They were found to carry a gene, optrA, that confers linezolid resistance.  This is the first time this gene has been found in a bacterium from a companion animal in the UK. optrA is found on a plasmid, a small piece of DNA that can be move relatively easily between bacteria, meaning it can potentially spread to other bacteria of the same species, or even to those of other bacterial species. There are no details in the reports I’ve seen about timing of the infections, and whether the cluster in the clinic was likely due to direct contact between animals, contact with a contaminated environment or contact with people who were either contaminated (e.g. carrying the bug on their hands from touching an infected animal or contaminated surface in the clinic) or colonized (i.e. people who harbour the bacterium in their intestines and can be a source of contamination themselves).

Where did the linezolid-resistant enterococci originate?

It’s hard to say from the limited information I’ve seen. It could have come from a person, as there are lots of instances of humans infecting their pets with a variety of bacteria. That’s largely how MRSA originates in dogs and cats, and other resistant bacteria that are common in humans have entered the pet population in this way.

Use of linezolid in animals should not have played a role. Articles have stated that linezolid is not used in dogs and cats in the UK, and while I question whether that’s actually true, linezolid use is so rare to non-existent in pets that there’s probably no realistic risk of emergence of resistance from use of that drug in these species. However, optrA doesn’t just confer resistance to linezolid. It also confers resistance to chloramphenicol and florfenicol, drugs that are (uncommonly) used in dogs and cats. This highlights the “co-selection” issue, when the use of one drug can select for resistance in other drugs. I suspect a human source is more likely here but it’s hard to say.

According to one article, the authors indicatedOur findings further the ‘One-Health’ view that antibiotic-resistant bacteria can be shared by animals and humans, although the direction of transfer is often difficult to prove. We currently do not know the prevalence of linezolid-resistant enterococci in companion animals and therefore a joint approach to monitoring emergence and dissemination of resistance mechanisms of public health importance is needed”, says Dr. Hopkins. “In this instance, further transmission was stopped by cleaning and decontamination and we have no evidence that any people acquired an infection from these animals.”

What this means in the big picture is hard to say, but it shows how resistant bacteria and resistance genes can move between and within species, sometimes in unexpected ways. It also shows how the common bug-drug-species focus (i.e. looking at one type of resistant bacterium in just one (human or animal) species) can miss the big picture. Antimicrobial resistance is a complex ecological problem that requires a complex and comprehensive approach, which is currently still lacking.

The snowfall we had on the weekend notwithstanding, spring is here. As the weather warms up in Ontario (and other regions), we have to once again think more about ticks. Once the temperature reaches ~4C, hungry ticks that didn’t feed in the fall will come out, looking for food. Accordingly, tick prevention for people and pets needs to be considered.

The return of ticks also means the return of pet tick preventative advertising, and that’s leading to confusion and questions. The “Lone Star Louie” ads, in particular, are leading to a rash (pardon the pun) of emails. They focus on the Lone Star tick (Amblyomma americanum), but also include some confusing, mixed and misleading messaging, talking about this tick in dogs, red meat allergy and Lyme disease.

First, the concern about the A. americanum

The Lone Star tick is an aggressive tick that can spread a few different diseases. We’re paying more attention to it in Ontario now because we expect it to become a problem over time. We see small numbers every year, and so far we’ve assumed that these are ticks have been carried north by migrating birds. Established populations (i.e. finding all life stages of the tick at a particular location, typically over at least a two year period) have not been recognized in the province (yet). However, we’re on the look out for it through initiatives such as our Pet Tick Tracker.

Next… questions about the advertising

Red meat allergy

  • This is a really interesting story but one that has no relevance to dogs and cats. Lone Star tick bites can result in an acquired red meat allergy in people. It’s uncommon, but bites from this tick can result in sensitization of peoples’ immune systems to a protein that’s found in red meat. People can get sensitized to it because it’s not a component of their bodies. In contrast, dogs and cats are made of that protein, so they can’t develop the same kind of red meat allergy (i.e. an allergy to themselves). So, while it’s a concern with this tick, it’s of no relevance to dogs and cats, and dogs and cats do not lead to people being exposed to the tick or developing the meat allergy.

Lyme disease

  • Lyme disease gets mentioned in the ad too, but this tick does not harbour the bacterium that causes Lyme disease (Borrelia burgdorferi).  That particular pathogen is most often carried by black-legged ticks (e.g. Ixodes scapularis).

So, the Lone Star tick is a concern (albeit still a minimal one in Ontario). However, red meat allergy messaging is irrelevant to marketing tick preventives for dogs and cats, and Lyme disease is not a risk from this tick. Tick prevention is important in dogs (and to a lesser degree cats) and the use of tick preventative medicine is an easy and effective way of reducing the risks associated with ticks. The messaging needs to be better, though, to avoid confusion and misinformation.

Raw diets have been in the news a lot lately because of Salmonella contamination. It’s not surprising at all since bacteria like Salmonella, E. coli, Campylobacter and Listeria are expected to be found in raw meat (that’s why we cook it). We know that dogs and cats fed raw meat are at increased risk of shedding bacteria like Salmonella, sometimes with serious consequences to the animals or their owners.

Reducing the risk is a challenge when you know there’s a reasonable chance the food is contaminated, and when the preferred method of control (cooking) isn’t used. Irradiation is an alternative approach, but not something in which a lot of raw feeders are probably interested. High pressure pasteurization (HPP) is therefore increasingly being used to help control bacterial contamination of these products. HPP, as the name suggests, uses high pressure (with minimal increases in temperature) to reduce bacterial loads.

Notice I said reduce, not eliminate.  That’s the problem.

A while ago, I used to go on the assumption that raw food products that underwent HPP were similar in risk to commercial cooked diets, with the disclaimer that we don’t really know for sure. We still don’t know a lot, but what we know now isn’t encouraging, so I’ve had to change that assumption.

I’ve talked to a few people who have done limited investigations of foods treated with HPP, and the results were disappointing. Unfortunately the studies were small and remain unpublished.

A 2016 research abstract gives us a bit more substance (although a proper research paper would be preferred). In that study (Hasty et al. 2016, Reciprocal Meat Conference – Meat and Poultry Safety), raw beef pet food was spiked with E. coli. (A harmless strain of E coli was used in place of a disease-causing strain or other bacteria like Salmonella, presumably because of biosafety concerns.) They used a HPP process that subjected the meat to a standard pressure (600 mpa) for 480 seconds. Then they checked to see if any viable bacteria were left in the meat.

The good news: There was a definite reduction in viable bacteria.

The bad news: It didn’t kill them all.

This doesn’t mean HPP is ineffective. It’s a matter of being aware of what it can do, and what it can’t. It can reduce the number of viable bacteria in the food, and that probably reduces the risk of disease in people and pets. But it does not eliminate all the bacteria, so it can’t eliminate the risk (only proper cooking and handling will do that).

If someone is going to feed a raw diet, I’d still recommend using a HPP-treated diet versus one that has bot been treated. However, people have to realize it’s not a panacea and that they still have to assume the food is contaminated.

Here’s a quick reminder of some basic take-home messages for raw meat feeding:

  • There’s always some risk of bacterial contamination. We can reduce, but not eliminate, that risk.
  • Careful handling is required to prevent cross-contamination of human foods, surfaces and environments. A little common sense when it comes to food handling can go a long way (but it’s amazing how uncommon “common sense” can be… check out Barfblog.com for annals of food safety stupidity).
  • Raw meat diets should not be fed to dogs and cats at increased risk of serious disease (e.g. very young, elderly, pregnant, immunocompromised) or in households where people (or pets) fitting those categories are present.
  • People who feed raw diets should make sure their veterinarian knows this, should their pet get sick. The same applies on the other side of the One Health spectrum – if someone is feeding raw meat to their pet and a person in the household has gastrointestinal disease, exposure to raw meat needs to be mentioned to the physician involved.

More information about raw meat feeding and basic safety practices is available on the Worms & Germs Resources – Pets page.

I guess we’re not the only ones dealing with Brucella canis issues lately. In February, we were dealing with B. canis in dogs imported into Ontario from South Korea. Currently, we’re dealing with a larger issue in commercial dog breeding facilities in Ontario.

Imported Brucella canis also appears to be an issue in the US at the moment.  Two dogs from South Korea that went to Wisconsin were recently diagnosed with brucellosis. They originated from a larger shipment of dogs from South Korea, and I have to wonder whether they’re from the same batch that came to Canada in February in which we found infected dogs (maybe they were even tested in response to what we found). Regardless, the imported dogs and the dogs that were exposed to them (a total of ~100 dogs) are under quarantine at the moment. Owners of dogs from the exposed group that have already been adopted are being contacted by state public health officers to instruct them to quarantine (and presumably test) the dogs.

The article was picked up by ProMedMail, with the following moderator comments:

“The lax import regulations of rescue animals coming into the USA is on the verge of a serious problem. The USA has quarantine facilities at ports for cattle, horses and other livestock. It needs to be expanded to include dogs and likely other animals. Imported rescue dogs especially need to have their vaccinations for prevention of rabies, distemper, parvo virus and other diseases. While being held at a facility, they should be checked for other diseases such as canine influenza and zoonotic diseases such as brucellosis.

Rescue animals from other countries need to be quarantined, not put in foster homes where there could be exposure to other animals or immunosuppressed individuals until some of these vaccines and testing have been performed. These quarantine facilities should be inspected by knowledgeable individuals according to law.”

Great in theory but it’s never going to happen. All we can realistically do is educate to improve importation practices to reduce the risks, but the risk will never be eliminated completely so long as dogs are crossing the border.