Worms & Germs Blog

Worms & Germs Blog

Promoting Safe Pet Ownership

Canadian spotlight report: Preserving antibiotics

By Scott Weese on Posted in Cats, Dogs, Horses, Other animals

Dr. Theresa Tam, Canada’s Chief Public Health Officer, has issued a spotlight report: Handle with Care: Preserving Antibiotics Now and Into the Future. 

There’s nothing too surprising in it, which in a lot of ways is the point. Addressing antimicrobial use and resistance isn’t rocket science, it’s application of a lot of basic, common sense measures. While that makes it sound like it’s an easy fix, it actually makes solving the problem harder in a lot of ways. There’s no magic bullet, no fancy new toy and no game-changing drug that will make this issue go away. It’s a need for improvement in preventive medicine, better access to healthcare overall, limiting use of antibiotics in situations where we very clearly know we don’t need to use them (or use as much of them) and, above all, changing the behaviours of patients, pet owners, farmers and prescribers (both physicians and veterinarians).

Raw diets and multidrug-resistant bacteria

By Scott Weese on Posted in Cats, Dogs

Back in 2008, we reported an association between feeding raw diets to dogs and shedding of cephalosporin-resistant bacteria in dogs (that makes me feel old… one of many things that does these days, I guess). It didn’t get too much attention at the time, since the main focus of the study was on Salmonella, the most commonly discussed concern with raw diet feeding. We also didn’t pay as much attention to those other bacteria 11 years ago.

I was speaking about antibiotic resistance at the 2019 ACVIM Forum in Phoenix AZ last week, and extended-spectrum beta-lactamase (ESBL)-producing bacteria kept coming up – not just from me, but also in lots of questions from the audience. ESBLs are enzymes that bacteria produce to break down some commonly used (and important) antibiotics, including 3rd generation cephalosporins. These bacteria also tend to acquire various other resistance genes, making some strains highly drug-resistant. ESBLs can be produced by a range of Gram negative bacteria, most notably E. coli, and these bacteria are causing more and more problems. Bacteria can also be resistant to 3rd generation cephalosporins via a different resistance mechanism that’s also of concern. Sometimes, studies focus just on ESBLs while others cover cephalosporin resistance by other mechanisms as well. Resistance by either mechanism is a problem.

One thing that got a lot of people talking at the conference was discussion of things that increase a dog’s risk of shedding ESBLs (or, more broadly, antibiotic-resistant bacteria). One risk factor is previous antibiotic treatment. That’s not surprising. The other big risk factor that’s come up in a few recent studies happens to be feeding raw diets.

  • Our study from 2008 reported dogs that ate raw meat were 15X more likely to shed cephalosporin-resistant E. coli.
  • A UK study reported an 11X higher risk of shedding 3rd generation cephalosporin-resistant E. coli by raw fed dogs. (Schmidt et al. 2015)
  • Another study from the UK reported that dogs that ate raw poultry were 48X as likely to shed ESBL E. coli compared to dogs that didn’t. (They were also 104X (!!) as likely to shed E. coli resistant to fluoroquinolones, another important drug class). (Wedley et al. 2017)
  • In a Dutch study, dogs that were fed raw meat were twice as likely to shed ESBL producing E. coli. (Baede et al. 2015)
  • The same Dutch group also looked at cats, and found that raw feeding was the only factor associated with shedding ESBL-producing bacteria, with a 32X increased risk. (Baede et al. 2017)

These results are actually not surprising.  Resistant bugs can be present in food animals, and those bugs can then contaminate the meat from those animals at slaughter or a subsequent step in the production chain. Measures are taken to reduce the risk, but whether it’s an “ultra-premium” raw diet product or meat from the local grocery store, there’s always some risk of bacterial contamination. That’s why we cook meat, and why we should always use basic hygiene practices to reduce cross-contamination and inadvertent exposure to harmful bacteria in the kitchen and elsewhere.

I won’t get into the whole raw diet discussion here but will hit on some of my highlights:

  • Raw feeding is associated with risk to the pet and owners, and should be avoided whenever possible.
  • In some situations, raw diets should never be fed to pets, including households with young kids, elderly individuals, pregnant women or immunocompromised individuals, or with animals that fit into similar risk groups.
  • High-pressure pasteurization likely reduces contaminant levels but doesn’t sterilize the food. If someone is going to feed a raw diet, they should use one of these diets but still consider the food contaminated.

More information about raw diets and how to reduce the risk when feeding a raw diet is available on the Worms & Germs Resources – Pets page.

Resistant hookworms: An emerging problem?

By Scott Weese on Posted in Dogs, Parasites

In a presentation yesterday at the 2019 ACVIM Forum in Phoenix AZ, Dr. Ray Kaplan from the University of Georgia gave a somewhat scary talk about the emergence of multidrug-resistance in the hookworm Ancylostoma caninum.

Resistant parasites don’t tend to get as much attention as resistant bacteria, but they can present similar challenges. The concern is that there is now pretty solid evidence of hookworms that are resistant to most or all approved drugs typically used to treat these parasites. It’s thought to mainly have developed in greyhound breeding and racing kennels, where there’s a lot of dewormer use and a lot of infection pressure, creating a perfect environment for emergence of resistance.

Resistance poses a particular risk to puppies, since hookworm infestations can kill young dogs. Adult hookworms live in the small intestine, where they attach to the intestinal wall and suck blood from the host. They are voracious feeders and large burdens can cause serious (or even fatal) problems because of the amount of blood that is lost. It’s also a concern from a public health standpoint – people don’t get the intestinal infection, but they can develop a condition called cutaneous larva migrans, in which the parasite larva in the environment penetrate and burrow though the skin, causing an extremely itchy rash that persists until the parasite ultimately dies or is killed. The same drug classes are used to treat this infection in people and dogs. In people, the infection typically will go away on its own even without treatment, but it can be very uncomfortable for a few weeks or months waiting for a resistant infection to naturally die out.

The scope of the resistant hookworm issue isn’t clear, but it’s something to be aware of. We commonly see recurrent hookworm infections because of what’s call “larval leak.” When a dog is infected with hookworms, they migrate throughout the body and can become dormant. After deworming eliminates the intestinal infection, these larvae can re-activate, make their way to the gut, and re-establish the infection. That’s not resistance, it’s the biology of the worm and is why repeated treatments are often needed.

Resistance is when the intestinal worms aren’t killed by the dewormer. Resistance is most easily detected by doing a fecal egg count reduction test (FECRT). That involves testing a fecal sample before and after deworming (before there’s enough time for larval leak), to see how much of a reduction in egg count occurred (which should correspond to the proportion of adult worms that were killed by the treatment).

Individuals and groups adopting greyhounds from US breeding and racing facilities should be particularly aware of the risk of resistant hookworms. Performing a fecal egg count reduction test should be a routine practice on newly obtained greyhounds, and is never a bad idea in any dog that is found to have a hookworm infestation.

The other big consideration is reducing exposure. Resistant parasites are another reason why it’s important for people to be responsible and pick up their dog’s feces. The less fecal contamination there is in the environment, the less exposure there will be of dogs (and people).

Dog owner antibiotic survey

By Scott Weese on Posted in Dogs

As part of our research into antibiotic use and resistance, we’re looking at what drives antibiotic prescribing, use and compliance. It’s a complex subject and needs to be approached from a variety of angles. One angle is looking at what pet owners perceive or want, as this can be an important influencing factor. To address this, we’ve launched a survey designed to gather information about pet owners’ perceptions and preferences when treating their pets for infection. The study is funded by the Ontario Veterinary College Pet Trust.  The survey is voluntary and anonymous.

If you own or care for a dog and are 18 years of age or older, you are invited to participate in this survey. Full details and ethics approval information are available here: https://uoguelph.eu.qualtrics.com/jfe/form/SV_5uUBn8xoG9kBLeJ

Cat owners… don’t feel left out. We’ll get to you soon!

Brucella canis updates: US dogs, Canadian person, and lots of Canadian dogs

By Scott Weese on Posted in Dogs

Brucella canis is getting a lot of attention these days, and taking up more of my time than I ever would have thought a few months ago.

Identification of infected dogs linked to a commercial breeder in Iowa (also see our previous post from Tuesday) has attracted a lot of attention. It’s hard to say how noteworthy it is, because we know the bacterium is present in some commercial breeding (puppy mill) operations and in imported dogs. It’s of particular concern because it can be transmitted to people, but we don’t know how much of a concern that is or how often it occurs. It seems to be rare, but it can occur (more on that in a minute).

The Iowa situation is still being sorted out, but may pale in comparison to what’s going on in Ontario. We detected Brucella canis in some imported dogs earlier this year, in a group of dogs imported from South Korea (positive dogs from the same region (possibly the same shipment) were later identified in the US as well). That caused a big stink at the time, but settled down.

Of greater concern is the more recent identification of Brucella canis in commercial breeding dogs in Ontario. We have over 100 known or suspected positive dogs (testing is a bit of a pain for this bacterium, to say the least), and since we certainly haven’t tested all (or even most) commercial breeding dogs in the province, it’s reasonable to assume that the true number of affected dogs is much greater.

So, what’s the risk to people?

  • We don’t know. It’s a rarely diagnosed disease in humans. The problem is that could be because it’s a rare disease, or because it’s an under-diagnosed disease. It’s probably a combination of both. It seems to be truly rare, but human infections do occur. The greatest concern involves kids, as they’re more susceptible to infection and severe disease, but it can affect others (see below).
  • As we’ve worked through the Ontario situation, my impression has been the overall risk to people is probably still quite low (dogs may be another story). Otherwise, we should have seen a reasonable number of sick people in Ontario. The lingering concern is whether there are infected but as of yet undiagnosed people in the province.

A recent report from of a British Columbia woman who was diagnosed with brucellosis highlights this concern. The woman had non-specific signs including fever, headaches and weight loss for two months before the diagnosis was reached. The link was believed to be a pregnant dog from Mexico (a place from where Brucella-infected dogs have originated before) that spontaneously aborted two stillborn puppies while being transported by the woman in question, who regularly helps move rescue dogs from the US and Mexico. That dog tested positive for Brucella canis and contact with aborted fetuses, fluids and other tissues would be high-risk for transmission of the infection to the person.

One case doesn’t mean it’s a big problem, but it means there’s concern. Here are a few take home messages:

  • Brucella canis is of greatest concern in imported dogs and dogs from commercial breeders.
  • If you purchased a dog from an internet source, pet store or anywhere else where you don’t have very clear information about the background of the dog, testing for Brucella is a reasonable idea.
  • If you are importing dogs or have adopted an imported dog, you should consider testing for Brucella, especially if it came from Asia, Mexico or eastern Europe.
  • All breeding dogs should be tested for Brucella at least once a year.
  • You shouldn’t freak out about Brucella because human infections seem to be rare, but you should be aware of it.
  • Dog owners should make sure their physicians know that they have dogs (as for any pet) and physicians should be aware of the zoonotic potential of Brucella canis.

For more information, check out the OAHN factsheet on Brucella canis for veterinarians and our archives.

Canine brucellosis international, factsheet for veterinarians

By Maureen Anderson on Posted in Dogs, Other diseases

Recently another couple of good examples have cropped up of the risks of canine brucellosis (caused by Brucella canis) associated with both canine breeding kennels and international movement of dogs.

The state veterinarian for Iowa confirmed that there were several cases of brucellosis diagnosed in dogs from a small breeding facility in Marion County.  Officials are attempting to reach any individuals who may now have a dog that could have been exposed at the facility, which is now under quarantine, and further testing is underway.  The same article mentions another breeder in Knoxville, Iowa that also had dogs that tested positive, and a local adoption service that purchased 32 dogs at auction at now has the entire group under quarantine while the dogs are tested.

Across the pond, in the Netherlands (a country known for its strict and typically quite effective infection control measures), Brucella canis was diagnosed in a domestically-bred dog for the first time, but ultimately the dog had international ties.  The case was discovered when a male dog from the breeding kennel that was originally imported from Russia was examined for back pain.  The dog was tested and found to be infected.  The cause of the back pain was likely discospondylitis, which is one of the well-recognized manifestations of brucellosis in dogs beyond reproductive issues.  The positive result prompted testing of other dogs at the facility, and one of the animals that had been born in the Netherlands was also found to be infected (not surprisingly).  All of the dogs at the facility were ultimately euthanized after consultation with government officials and the owner.  Officials are also doing everything they can to track down anyone who adopted a dog from the kennel to advise them of the risks and hopefully prevent further spread.

It’s important for veterinarians, dog breeders and owners to be aware of the risks of canine brucellosis, as it can infect both dogs and people.  It is especially important to be careful about imported dogs, or those with limited medical history that could have come from a high-risk facility.  The Ontario Animal Health Network (OAHN) has produced a handy factsheet on Brucella canis for veterinarians to help navigate the issues, and particularly the diagnostic testing process which involves several different kinds of tests.

More information about B. canis can also be found in our archives.

Itchy dogs: Topical treatments and culture-critical cases

By Maureen Anderson on Posted in Dogs

The latest companion animal infographic from the Ontario Animal Health Network (OAHN) is now available!  Currently the network is working on a series of infographics focused on good antimicrobial stewardship.  Stewardship includes knowing when NOT to use antimicrobials, and what to use when antimicrobials are needed.  Guidance is available from leading veterinary infection control experts, through the open-access ISCAID Guidelines for the diagnosis and antimicrobial therapy of canine superficial bacterial folliculitis (Hillier et al. 2014).  Click here to download the infographic in pdf.

The infographic is a handy visual reminder of things to think about when dealing with some of these itchy dogs as the weather warms up.  You can also find more infographics and resources on www.oahn.ca.  If you are a veterinarian or technician, you can sign up for the quarterly companion animal OAHN report, and also help contribute to disease surveillance in Ontario through our 5-minute clinical impressions survey once every quarter!

Small animal infectious diseases, and how they get around

By Maureen Anderson on Posted in Cats, Dogs, Other diseases

The latest issue of Veterinary Clinics of North America: Small Animal Practice includes a number of chapters on infectious diseases that have been making regular appearances on this blog, including rabies, influenza, brucellosis, Lyme disease, and more, as well as chapters on certain feline-specific infectious diseases.  Check out the full table of contents and summaries here.

While we can’t provide direct access to the full content of the issue, we worked directly on two of the chapters (along with our colleague Dr. Jason Stull from The Ohio State University) and are therefore able to share the author links to the sections on the dynamic nature of canine and feline infectious disease risks in the 21st century, and the impact of dog transport on high-risk infectious diseases.  These links will be active until June 22, 2019, after that access will only be by subscription (institutional or otherwise) or purchase.  If you can, we encourage you to check out the other great content in this issue as well!

US ban of importation of dogs from Egypt

By Scott Weese on Posted in Dogs, Rabies, Vaccination

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.

Rat bite fever on Vancouver Island, Canada

By Scott Weese on Posted in Other animals, Pocket pets

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.