Worms & Germs Blog

Worms & Germs Blog

Promoting Safe Pet Ownership

Human rabies, BC Canada (2019)

By Scott Weese on Posted in Rabies

Rabies is a high-profile disease and human rabies is exceptionally rare in Canada. While rabies is relatively widespread in wildlife in North America, it’s is rare in domestic animals in Canada, and spillover into people is fortunately rarer still because people have less direct contact with wildlife reservoirs, and because post-exposure prophylaxis is so effective if it is given in a timely manner.

However, the risk is ever-present, as was demonstrated by the recently reported case of rabies in a 21-year-old man from British Columbia, the first human rabies death in Canada since 2012, and only the second case on record in BC (the first case in this province was in 2003).

The man was infected after contact with a bat on Vancouver Island in May.  The bat reportedly merely “ran into his hand” so he likely did not realize the risk at the time and did not seek medical attention.  But bats have very tiny teeth, and a small puncture wound from a bat bite can be easily overlooked.  If there’s little damage from the bite and people don’t know about the rabies risk, the contact may go unreported, as in this case.  The encounter only came to light after the young man began to show signs of disease.  Rabies is basically 100% preventable of post-exposure prophylaxis is provided, but it’s almost 100% fatal otherwise.

Rabies infections like this are the tragic result of a breakdown in education and communication regarding rabies risk. People need to know when rabies exposure is a concern, to make sure they seek proper medical care. We have a good public health system that’s adept at handling rabies exposure, but it’s all for naught if the exposure isn’t reported. This case highlights the need for ongoing rabies education, despite the rarity of rabies in people in North America.

Rabies warning at Epcot

By Scott Weese on Posted in Cats, Rabies

I’ve been slow to write about this (and other things lately… busy/lazy) but a rabid feral cat found in the vicinity of Disney’s Epcot Center in Orlando, FL  has attracted a lot of attention. The Department of Health in Orange County has issued a 60 day alert for a two mile radius around where the cat was found, an area that hits Epcot.

Why 60 days?

  • Who knows? You have to pick a number. That’s about all the science that went into that, I assume (since raccoon-variant rabies and bat rabies are both still endemic in most parts of Florida).

Anyway, two Disney employees were scratched by the cat when they encountered it in a parking lot of an office building outside the park. It’s not clear why the cat was caught and tested, and whether it had signs of rabies, but it was, and it did.

Scratches aren’t typically considered a risk for rabies exposure but they’re a grey area. Rabies is transmitted by saliva. There are no salivary glands in claws. However, there’s a theoretical potential of rabies virus being there if the cat had just licked its paw, or if saliva was deposited on the person’s skin during a struggle and was driven into the body by the scratch, or if saliva came in contact with the broken skin afterward. So, while scratches are not technically considered a source of exposure by some guidelines, it’s a case-by-case decision, depending on the circumstances. Since rabies is almost invariably fatal but almost completely preventable with post-exposure prophylaxis, treatment of people that are scratched isn’t uncommon.

What does this mean for anyone visiting Disney?

  • Not much. Rabies is endemic in wildlife in Florida. While dogs get more attention, cats are the most commonly affected domestic animal, probably because outdoor cats tangle with wildlife more often and are less likely to be vaccinated.

This doesn’t really change the messaging relating to contact with animals at Disney, or elsewhere.

  • Stay away from unknown animals.
  • If you are bitten or scratched, wash the area thoroughly with running water.
  • Identify the animal, it at all possible, since if it is caught and quarantine or tested, it’s rabies status can be definitively determined.
  • Stay away from unknown animals. (Yes, I realize I already said that, and yes, that includes cute little stray kittens, since they are an important source of rabies exposure.)

Maybe they need to get rid of all of those over-sized mice in Orlando to help reduce the feral cat population.

Carbapenemase-producing E coli in a veterinary hospital

By Scott Weese on Posted in Cats, Dogs

New antimicrobial resistance challenges continue to emerge. In the veterinary field (especially in small animals), we have the advantage of seeing what’s happening in human medicine first, since that’s often an early warning system for what we’re going to encounter. We’ve seen a variety of resistant bacteria first became a problem in people, and then became a problem in animals, either because of spread of the bacterium from people to pets, or because of the same inciting cause (antibiotic use) leading to development of similar issues.

Lately, we’ve been working on a lot of resistant Gram negative bacteria like E. coli. In particular, we’ve been studying E. coli (and other bacteria from the Enterobacteriaceae family) that produce extended spectrum beta-lactamases (ESBLs). These are enzymes that break down a range of antibiotics in the very commonly-used penicillin and cephalosporin classes. The bacteria also tend to become resistant to other antibiotics at the same time (by acquiring other resistance mechanisms), making them potentially even harder to treat. A common solution for for infections involving ESBL bacteria is to use drugs from the carbapenem class, such as meropenem.

Unfortunately (but not surprisingly), more use leads to more resistance. Carbapenemase-producing Enterobacteriaceae (CPE) are now a big problem in human medicine as they can be very difficult to treat, especially since some have developed resistance to other last resort drugs as well.

We’ve been looking out for these in veterinary medicine. I’ve seen a few cases, all from the US so far. We don’t use meropenem much (although it can be overused), so there’s less selection pressure in our veterinary patients. However, with more antibiotic use of any sort, rare use of meropenem and the potential spread of CPE from humans to their pets, we’ve known it’s coming.

Our concerns are highlighted but a cluster of 15 cases of CPE infection at the University of Pennsylvania’s small animal hospital. Here’s a summary of the cases from the hospital:

Fourteen dogs and one cat were diagnosed with CPE in the past year.  That’s a pretty astounding and concerning number.

  • A cluster of 6 cases was identified in their ICU in July 2018. A second cluster of 3 cases was identified in September and an additional 6 were identified through June 2019 (it’s not clear to me whether the latter group was a cluster or independent cases).
  • Infected animals were isolated as per hospital protocols.
  • Carbapenem resistance in these cases was due to a gene called NDM-5. Finding the same uncommon gene in multiple isolates of the same bacterial species suggests that these are all linked, but it’s hard to say how the different clusters relate (or if they do).
  • 13/15 infected animals were discharged from the hospital and two were euthanized because of unrelated problems. CPE is usually treatable if the diagnosis is made and a appropriate antimicrobial (and adjunct) therapy is started in a timely manner.

From a population standpoint, I’d be happy to hear that these were all linked infections. That’s not something we want to see in a hospital, but 15 linked cases would be better than 15 individual cases, since the latter would suggest there’s a lot of CPE in the community. CPE are no more likely to cause disease than susceptible Enterobacteriaceae, they’re just harder to treat when they do. Diagnosed infections presumably represent the minority of infected dogs and cats, since the bug most often lives harmlessly in the intestinal tract (and gets passed in the feces, thus creating exposure risk for other animals and people).

One concern here is what happened after discharge from the hospital. An animal with a CPE infection probably also has the bacterium living in its intestine. It’s been shown that dogs infected with ESBL-producing Enterobacteriaceae can shed the bacterium for months. We don’t know much at all about CPE shedding in dogs and cats, but it’s likely that some of these animals have been (or still are) shedding CPE.

This won’t be the last we hear about CPE in dogs and cats. Hopefully it remains a rare issue but we’re trying to figure out more about these bugs and how to limit their spread.

Canine influenza, California/Oregon (2019)

By Scott Weese on Posted in Dogs, Vaccination

Canine influenza is (once again) causing big problems in some parts of the western US. Following reports of influenza outbreaks in animal shelters in Oakland, California, it’s apparent that it has spread within California shelters and to an Oregon shelter. It is also affecting pet dogs in various cities in California.

It’s not surprising that these problems have surfaced again. H3N2 canine flu has been present in the US since it was first introduced from Asia in 2015, and continual re-introductions are probably occurring from importation of dogs from endemic areas. That’s how we got it in Canada, but we were able to contain and eradicate it Ontario (twice).

Here are a few key points for people in affected areas OR who are travelling with dogs to those areas OR moving dogs from those areas.

  • Canine influenza looks like any other type of “kennel cough.” There’s nothing clinically that says a dog’s illness is “flu” vs “not flu.” Dogs with respiratory disease that have been in affected areas should be considered flu suspects.
  • If your dog has a fever, cough, runny nose or eyes, or any other signs of respiratory disease, keep it away from other dogs. Dogs can shed H3N2 for a few weeks, so keeping any flu cases isolated from other dogs for at least 28 days is the goal.
  • If your dog has signs of respiratory disease, definitely don’t take it to a kennel or other place where there are lots of other dogs. That’s how we end up with rapid widespread transmission.  When the flu virus gets into a place like a shelter or kennel, it spreads quickly. Often, most or all dogs get infected. Some might not look sick, but they can still be infectious.
  • If you think your dog might have flu, call your vet. Don’t just show up at the clinic. If your dog needs to be seen by a vet, calling in advance can let them make plans to reduce the risk of exposure of other dogs at the clinic.

Vaccination against H3N2 can be useful but cannot be relied on as the primary means of infection control. It’s like any influenza vaccination (including the ones used in people) – it’s not going to totally prevent most individuals from getting infected. It’s designed to reduce the incidence and severity of disease. For me, its role is to reduce the likelihood that an infected dog will get seriously ill or die. That’s certainly useful, but vaccination is not a way to prevent flu from getting into a kennel or shelter, or spreading once it’s there.

While canine flu is highly contagious, it can be contained, with effort. We were able to contain it when it hit Ontario a couple times in 2018, with a lot of testing, communication, quarantine and probably a healthy dose of luck, to be honest. Sometimes, people take an “oh well, it’s here and there’s nothing we can do” approach. There’s almost always something that can be done -usually good ol’ basic infection control measures will go a long way.

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 2019 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 News.

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 (causing ear infections) or wounds (e.g. cuts, diabetic ulcers, leading to wound infections), or infections of indwelling devices like feeding tubes and catheters (either from close contact of the animal with the insertion site or contamination of the person’s hands, resulting in contamination of the insertion site).  Anytime pet saliva reachs non-intact skin or mucous membranes (e.g. 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.

Twenty-nine cases 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 drool
  • “Falling down when drunk and contaminating abrasions with dog saliva” (Okay, 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 points but the take-home message remains unchanged: there is a variety of 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 and cat saliva with broken skin is another. The higher risk the person, the greater the required diligence in terms of avoiding saliva and responding promptly when there is contact (i.e.  washing).

A little common sense and hygiene go a long way.  Avoiding getting fall-down-drunk and not eating food partially consumed by dogs would fit into those categories as well.

“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 statement 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 infosheet from the school and have to sign something every time one of my kids does any other type of activity, there was no notice about this particular activity, 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 after the incident. 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. The chicks are also being kept in a classroom where the students eat.

A lot could be done to minimize and communicate the risks. We tried approaching the provincial Ministry of Education and school boards quite a few years ago to look into animal exposures in schools, 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 13th, 279 infected people have been identified in 41 states, with cases dating back to January 1st, 2019 (see map below). That probably means a few thousand people have actually been infected, since reported disease numbers are typically 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 children younger than 5 years old, which is the group that typically gets 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 infected individuals 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).