Worms & Germs Blog

Worms & Germs Blog

Promoting Safe Pet Ownership

Pasteurella Infections Not From Bites

By Scott Weese on Posted in Cats, Dogs

Part of me thinks this is interesting and part of me wonders why it’s noteworthy. Let’s go with the first thought and consider the interesting aspects of a presentation at the recent ASM Microbe Conference, “79 cases of pet associated Pasteurella multocida infections in a 30-month period with reports of novel modes of non-bite transmission and their significance”, as reported by Healio Infectious Disease.

Pasteurella multocida is a bacterium that’s commonly found in the mouths of dogs and cats. So, not surprisingly, it’s commonly associated with bite infections. However, since it’s in saliva and exposure to dog/cat saliva isn’t uncommon, other routes of infection are possible. There are lots of case reports from things like dogs licking faces (ear infections) or wounds (e.g. cuts, diabetic ulcers), or infections of indwelling devices like feeding tubes and catheters (either from close contact of the animal with the site or contamination of the person’s hands, resulting in contamination of the site). If pet saliva can reach non-intact skin or mucous membranes (nose, mouth, eyes…), there’s some, albeit low, risk of infection.

The conference presentation by Dr. Don Walter Kannangara described  79 cases of Pasteurella multocida infection in people over a 30 month period. 43% of those were not linked to a bite, which is a somewhat impressive number.

Of the 79 cases, 29 were linked to cat bites and 16 to dog bites. The rest had various assumed non-bite exposures, including:

  • Licking wounds or ulcers
  • A foot with a diabetic ulcer stepping on dog saliva
  • “Falling down when drunk and contaminating abrasions with dog saliva” (Ok…that’s a new one for me)
  • “Epiglottitis (inflammation of a structure in the throat) after eating peanut butter and crackers that had been half-eaten by a dog” (Gross….also a new one for me)

The report has some interesting aspects but the take-home message is remains unchanged…there are various bacteria present in dog and cat saliva that can cause disease. It rarely occurs but it can, and it’s more common in people with wounds, compromised immune systems and the very young or very old.

Avoiding bites is obviously a key preventive measure.

Avoiding contact of dog saliva with broken skin is another. The higher risk the person, the greater required diligence with saliva avoidance and response (prompt washing).

A little common sense and hygiene go a long way (avoiding getting falling-down-drunk and not eating food partially consumed by dogs would fit into those categories).

“Dad, A Chick Pooped on Me”

By Scott Weese on Posted in Other animals, Salmonella

How’s this for timing? As I was writing the post below, my youngest daughter walked in the door and said “a chick pooped on me today“.

It wasn’t a total surprise since I’d heard a vague thing from her about maybe having chicks in the class for the end of the year.

Is it potentially fun and/or educational?

  • Sure. If it’s done right.

Is it done right?

  • Doesn’t sound like it.

Chicks are cute and can be entertaining. They can also be educational. Yet, contact with them is clearly associated with disease. While I get an info sheet and have to sign something every time one of my kids does any other type of activity, there was no notice about this from the school, no information about risks and preventive measures, nothing about what to do if a child is at high risk for severe disease or anything else.

Just my kid telling me she got pooped on.

I’m not overly concerned. She’s healthy, outside of the main high risk groups and washed her hands. Yet, I don’t know (and doubt the school knows) whether that applies to everyone in the class or other kids that might have contact with the chicks. They’re also being kept in a classroom where kids eat.

So, a lot could be done to minimize the risk and to communicate the risk. We tried to approach the provincial Ministry of Education and school boards quite a few years ago to look into animal exposure in school and there was basically zero interest in the subject (whether that’s because there was no awareness of the issues or no desire to find out what’s actually going on is hard to say).

Now on to the post I was writing……

CDC has related an updated investigation notice about Salmonella from backyard poultry. As of June 13, 279 infected people were identified in 41 states. That probably means a few thousand people have been infected, since reported disease is dwarfed by the real number of cases.

  • The strains that have been linked to the outbreak are Salmonella Agona, Anatum, Braenderup, Infantis, Montevideo and Newport
  • 30% of infected people were kids younger than 5, the typical group to get sick or seriously ill from Salmonella.
  • 26% of people were hospitalized. Fortunately, no deaths were reported.
  • About 40% of isolates were multidrug resistant.
  • 77% of people with those strains reported contact with chicks or ducklings from places like agricultural stores, mail order supplies and hatcheries.
  • One of the outbreak strains has also been found in backyard poultry in Ohio.

I’m not against animals in schools or backyard poultry. I’m just against being stupid. There are lots of things that can be done to reduce risks, and too often those easy, cheap and practical measures are ignored.

Canine rabies imported from Egypt to the US, 2019

By Scott Weese on Posted in Dogs, Rabies, Vaccination

During today’s Public Health Agency of Canada webinar, part of a new webinar series on zoonoses and adaptation in a changing world, Chelsea Raybern from the Kansas State Deptartment of Health and Environment provided a report about rabies in a dog that was imported into Kansas from Egypt in 2019.

The dog had been in the US for a little under a month when it developed some vague health problems. It then started acting strangely and ate a blanket. It was taken to a veterinary clinic, where it bit a technician. It had some neurological abnormalities, but was sent to another clinic for exploratory surgery because of the blanket-eating, thinking the abnormalities may have been due to an intestinal complication. However, the dog’s neurological only got worse shortly after surgery and it was euthanized. Because a person was bitten at the first clinic, the dog was tested for rabies and turned out to be positive.

This led to an investigation of both how the dog got rabies and who was exposed along the way. The dog was part of a shipment of 26 dogs that came from Egypt. All dogs in the group had documentation of rabies vaccination and rabies serology (i.e. a blood test that verifies the animal has antibodies against the virus, indicating it responded to vaccination). However, the testing that was performed on the group suggested that most of the dogs had in fact not been vaccinated, or at least not effectively vaccinated.

Investigation of contacts with the dog resulted in 39 people from the veterinary clinics involved receiving post-exposure prophylaxis (PEP). That turned out to be overkill, but was driven by the corporation that owned the clinic(s), before public health had a chance to investigate and determine who was really at risk and needed PEP. Most people at the clinics would not have been exposed to rabies by this dog. Five rescue staff and two people from the foster family also received PEP. Twelve dogs at the foster residence were also exposed, and ended up with 45 day to 6 month quarantines, depending on their vaccination status.

The rabid dog had been at a shelter in Egypt for 3 years prior to being exported. It was allegedly quarantined at the rescue before being shipped but it was reported that the “quarantined” dogs were mixing with dogs brought in off the street. So, all of the imported dogs in this group were considered potentially exposed. They were therefore all quarantined for 4-to-6 months.

This case was the 3rd rabid dog in the US from Egypt in the past 4 years, leading the US to suspend importation of dogs from Egypt. (There is still no corresponding ban in Canada).

What does this show?

  • Canine rabies is still common in some areas of the world. Travelers and dog importers need to remember that.
  • Rabies vaccination is highly effective… if it’s given at the right time (e.g. before exposure) and if the vaccine is effective (e.g. not out of date, properly handled, kept cold). Unfortunately, vaccine certificates from certain countries are not always reliable.
  • Importation of dogs from areas where rabies is endemic is risky. The incubation period can be weeks to months, so a rabid animal can look perfectly healthy when it arrives (or even after a short quarantine period).
  • Rabies must be considered anytime a dog bites someone. It’s particularly important if the dog is from an area where rabies is endemic. Biting dogs must be quarantined for 10 days to watch for signs of neurological disease, and/or tested.  Dogs can only be tested after they are euthanized, because the test requires brain tissue.

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!