Lyme disease is accompanied by enough paranoia. Bad headlines don’t help.
A recent article on The Daily Mail is about Lyme disease and pets. It’s actually not a bad article, outlining some important areas. However, the headline shows a big disconnect between some good stuff in the article and a complete misunderstanding of the situation.
The title: Warning to dog owners over the ticks that can wreck lives: Many are unaware their pets can transmit potentially deadly Lyme disease to them, say vets
To be brief, pets can’t transmit Lyme disease. Ticks that infect pets can also infect people, but that’s it.
Dr. Jason Stull (newly minted Canadian) spearheaded a commentary in the Canadian Medical Association Journal with Dr. Jason Brophy (infectious diseases physician) and me. The article raises the issues of zoonotic diseases and pets, particularly in high risk people, and the need for physicians to have increased awareness. It outlines some of the important issues, how pets and pet contact are common, what things increase the risk, the need for more information about pet-associated disease and the need for people to take reasonable precautions.
The title of the paper is important to consider “Reducing the risk of pet-associated zoonotic infections“
The paper’s attracted a lot of attention. Some good. Some not.
Many reporters have spun it towards sensationalizing the risks. Here are some examples of headlines.
Experts warn pets can cause illnesses, especially in immunocompromised owners
Your furry friend may be carrying diseases
Pets can make their owners sick, researchers say
Who let the dogs out? Pet therapy's hidden danger
...and my favourite
8 disgusting diseases you can catch from your pet
I guess those headlines are catchy, but the key points aren’t that your cat’s likely to kill you.
- Physicians need to query pet contact
- People need to think about basic practices to reduce the risk, especially in high risk households.
- We need more information about pet-associated diseases
“Wash your hands, don’t eat poop and don’t be stupid, researchers say”
“Docs need to ask if patients have contact with animals”
would be more accurate, but maybe not as catchy.
Probiotics are popular treatments, but marketing massively outstrips research. A few years ago, I worked on probiotic development in horses. We found what looked like a good bug, and instead of just trying to sell it, we did a proper trial. Despite the good in vitro properties, it actually caused diarrhea in foals compared to a placebo group.
Oops. (Does that make me a bioterrorist or just a really bad probiotic developer?)
Anyway, history repeated itself with another probiotic trial in foals that was just published (Schoster et al, J Vet Int Med 2015). Despite some nice properties in the lab, foals treated with this bacterial combination were more likely to develop diarrhea that required veterinary care compared to untreated foals.
I don’t mean to say that all probiotics are bad. However, the “well, you have nothing to lose” approach that we’ve often taken to probiotics (and other nutraceuticals) may not be the right approach. Probiotics, and other nutraceuticals, should be properly scrutinized like any treatment.
It’s great to see some places taking service dog fraud seriously. I’ve ranted about this before because I’m a strong believer in the need for service dogs to have full access, and the need to make sure that’s not screwed up by selfish people that don’t actually have a service dog. Too many people are claiming their pets are service dogs to be allowed to take them places where they are banned and too many unethical companies sell paraphernalia that people use to identify their dog as a ‘service dog’. When things go wrong or when people get fed up and assume that any dog not accompanying a blind person is a fake, the true service dogs get compromised.
As reported in the National Post “They may continue to overrun grocery stores and airplane cabins in the rest of the continent, but a new provincial law is declaring fake service animals will no longer be welcome in British Columbia.”
BCs proposed Guide Dog & Service Dog Act would result in true service dogs being given government-issues ID.
It’s great to see, it’s about time and other jurisdictions should be following this closely.
Anyone who’s had norovirus gastroenteritis knows that it’s pretty nasty. It spreads easily from person-to-person, and from (gross, yes, but true) vomit- and diarrhea-contaminated surfaces. The last thing we need is another source of infection to worry about.
The potential for dogs to be sources of norovirus has gotten a lot of attention (often misguided) over the past few days, because of a recent research paper from the UK (Caddy et al, Journal of Clinical Microbiology 2015).
The key components of the study and its results were:
- Stool samples were collected from dogs with and without diarrhea. The virus wasn’t found in any of 248 samples
- Blood samples were collected and tested for antibodies against norovirus: 33% were positive, suggesting the dogs had been exposed to norovirus in the past and mounted an immune response. That doesn’t mean they were sick or able to infect others, just that they were exposed and their bodies reacted to the virus, as they should. This has been reported before.
- Saliva samples were collected from a small group of dogs to test the virus's ability to attach to canine saliva. Norovirus was able to attach to saliva from all dogs.
- Intestinal tissues from some research dogs were collected and tested for the ability of norovirus to attach. The virus could attach to all the intestinal samples.
Surprisingly, they didn’t test dogs owned by people with norovirus infection. I would have thought that would be the highest yield way to determine if dogs can be infected and shed the virus. It’s harder to do a study like that, since you have to have a way to identify infected households and get samples quickly, but it would be the most informative approach. You could test 248 people in the general population and not find norovirus, but that doesn’t mean people aren’t susceptible or able to shed the virus. Testing dogs that have been exposed to people with norovirus to see if they are able to shed the virus, and therefore be a potential source of infection, is an important next step to determine whether there is any potential issue here.
So, should we be concerned?
Probably not. This study showed that dogs can be exposed (no surprise there) and that their bodies can respond to the virus. Mounting an immune response doesn’t mean that the virus was able to grow in the body and be shed. It’s interesting information but far from evidence that dogs are a concern. The authors rightly conclude “In summary, whereas HuNoV infection of dogs has been shown to be theoretically possible, the risk of this causing significant clinical disease in dogs is believed to be very low. ”
There are a lot of things that dogs get exposed to that they can’t then pass on. If dogs could infect us with everything to which they could produce and antibody response, we’d be in trouble. So, it’s an interesting piece of research that gives more support to the notion that we share a lot with our animals. However, I don’t think it indicates much to be worried about at this point.
There's no answer to how Asian H3N2 canine flu arrived in North America, but importation of infected dogs seems likely. There seems to be quite a bit of dog movement from Korea to the US, as highlighted in a couple of articles below. There's no way to know for sure, but well meaning yet unregulated dog "rescues" are probably a leading candidate for how the virus got here in the first place.
January 2015: Twenty-three dogs rescued by Humane Society International from a dog meat farm in Seoul arrived in Washington, DC... As for the rescued dogs, after some quarantine time and health checks, and some additional socialization, they will begin the final leg of their journey: finding homes. Some dogs will stay at the Animal Welfare League of Alexandria, which coordinated the shelter placement of the dogs here in the United States. Snowball and several other dogs will go to the Fairfax County Animal Shelter, and still more dogs will head to the Animal Welfare League of Arlington, the City of Manassas Animal Control and Adoption Shelter, Loudoun County Animal Services and the Washington Animal Rescue League. HSI, the international affiliate of The Humane Society of the United States, is working to reduce the dog meat trade in Asia, including South Korea, where dogs are farmed for the industry. HSI hopes to work with more South Korean dog meat farmers to help them transition out of this cruel business.
March 2015: Fifty-seven dogs and puppies have been rescued from a dog meat farm by Humane Society International and Change for Animals Foundation in South Korea. The dogs are now on their way to new lives in Northern California. HSI flew the dogs to San Francisco to be evaluated and treated for medical issues at the San Francisco SPCA. Some of the dogs will be transferred to additional HSI Emergency Placement Partners, including—East Bay SPCA, Marin Humane Society and the Sacramento SPCA. After a brief quarantine, they will be evaluated, spayed and neutered, treated for any medical issues, and made available for adoption. It will be at least two weeks before adoptions are possible.
These are probably just the tip of the iceberg when it comes to importation of dogs from Asia.
Infection control in veterinary clinics has come a long way in the past few years. However, there are still many challenges, and new situations like the large H3N2 canine flu outbreak in the US Midwest raise more issues. Just like human hospitals, vet clinics need to be proactive to reduce the risk of flu virus transmission between visiting patients. There’s always some inherent risk because sick animals go to vet clinics, and because healthy animals can also shed flu virus; however, there are ways to reduce the risk.
One of the most important and easiest things to do is to query each dog's health status and potential for influenza virus exposure at the time the appointment is booked, if the dog will be coming in in the next few days.
- If the dog has signs that could be consistent with influenza, or if the dog may have been exposed, it can be handled differently at admission (see below).
Have vigilant front office staff looking for sick dogs.
- If a dog enters the clinic and looks sick (and there isn't a known non-infectious cause for it), it should be flagged as a flu suspect.
Put a sign up on the door asking people to not bring dogs into the clinic that have a cough or that have potentially been exposed to canine influenza virus.
- Instead, have them call ahead (even if it's from the car) or come into the clinic without the dog first.
Have a plan for handling suspected cases that make it to the clinic.
- The goal is to make sure sick dogs stay away from other dogs, and that personnel handle them with appropriate protective gear (to prevent personnel from passing it on to other dogs via their clothing).
- Once you have a plan, write it down so that all the staff are clear on the details and can refer back to it as needed.
- Have the owner call upon arrival or come into the clinic without their dog to check in.
- Admit the dog directly to isolation through a side or back door, if possible. Otherwise, take it directly to isolation or an examination room, avoiding contact with other dogs. Do not let the dog wait in the waiting room.
- Handle the dog from the start using enhanced protective clothing (e.g. disposable gloves, designated gown or lab coat) that will not be used on other patients.
- Use good general infection control practices. Wash hands after removing gloves. Change protective gear properly so that underlying clothing is not contaminated. Clean and disinfect the environment and common contact items (routine disinfectants, if used properly, will easily kill influenza virus).
- If a suspect must be hospitalized, keep it in isolation and use proper isolation protocols.
It’s not rocket science, nor is it expensive or time consuming. Like most good infection control practices, it just takes some common sense and attention to detail.
Not surprisingly, I’ve been inundated with emails and calls about the H3N2 canine influenza outbreak that’s ongoing in the US.
How far will it spread?
- Who knows? It’s always hard to predict what will happen with influenza viruses. The spread of the H3N8 canine flu virus was surprisingly slow and sporadic, and it has yet to establish itself in Canada. This new H3N2 strain concerns me more because it might be more transmissible, and the Midwest US outbreak is unlike what we’ve seen in the past with H3N8. I suspect it will continue to spread, at least for a while.
How do we contain it?
- Basic infection control measures.
- If your dog is sick, keep it away from other dogs. Influenza viruses are only shed for a short period of time, so keeping sick dogs away from other dogs for 7-14 days will help.
- If your dog has been exposed to dogs that might have been infected, keep it away from other dogs. It doesn’t matter if your dog is healthy. Peak flu shedding can occur very early in disease, and a lot of virus can be shed in the 24 hours before the dog starts to show signs of illness. So, keeping exposed animals away from others for 7-14 days after exposure is also a good idea, just in case.
- Don't travel to an endemic region with your dog. If you are going on a trip to Chicago or other area where H3N2 is active and you don't need to bring your dog along, then don't risk exposing your dog, and/or possibly bringing the virus home with it.
- Don’t travel out of an endemic region with your dog. Likewise, if you live in an area where H3N2 is active, don’t take your dog on a trip anywhere else. If it was infected before leaving, it could take the virus to a new region.
- Don’t import dogs from shelters, puppy mills or similar facilities in areas where H3N2 is active. Animals from these facilities are at higher risk for carrying many diseases, now including canine flu.
- If the virus is active in your area, decrease dog-dog contact. Staying away from places where lots of dogs congregate (e.g. dog parks) can reduce the risk of exposure.
- If you think your dog might have canine flu, don’t rush it to your vet. It might need to go to the vet, but that depends on severity of disease. Regardless, the best approach is to call first and mention the potential for influenza so that the vet clinic can take precautions (more on that coming soon in another post).
Does this virus pose a risk to people?
- Probably not (or very limited), but flu viruses like to change. So, using basic infection control practices around infected dogs makes sense. It's also important that situations in which people and dogs in the same household have respiratory disease be investigated to make sure that there hasn't been interspecies flu virus transmission.
In a bit of a surprising twist, research performed by Cornell University, the Wisconsin Veterinary Diagnostic Laboratory and the National Veterinary Services Laboratory has indicated that the large, ongoing canine flu outbreak in the midwest US is being caused by an H3N2 influenza strain, not the expected H3N8 canine flu strain. Molecularly, the strain is closely related to H3N2 strains that are circulating in dogs in China and South Korea. H3N2 canine flu emerged in that region in the mid 2000s and is widely circulating in some areas.
This raises a few questions:
1) How did it get here? The importation issue comes up again, but potential sources need to be investigated.
2) Will the canine H3N8 vaccine provide any protection? I suspect no.
3) Does this change the response? Not really. Identifying potentially infected dogs and keeping them away from other dogs is still a key control measure. Vaccination is unlikely to be effective but still isn't a bad idea, in case it provides some limited protection and/or if there is also H3N8 circulating in the region.
4) Does this explain why the outbreak is so big and seems to be expanding? Maybe. I've been a bit surprised at the scope of this outbreak given what we know about H3N8 canine flu. This strain might be more transmissible, shed for longer periods of time or have other differences that make it spread more easily in the dog population. The Asian H3N2 strain has been shown to be highly transmissible and able to cause severe disease (Kang et al Vet Res 2013).
5) Who else can get infected? Asian H3N2 has been shown to be able to infect cats (Song et al, J Gen Virol 2011). There is currently no evidence of human risk, as far as I know, but this needs to be investigated since flu viruses are unpredictable. Given the large number of infected dogs, it should be possible to determine whether there are some associated human cases. The risk is pretty low but it's wise to look.
A GoFundMe campaign is underway to pay the vet bills for a sick dog that was imported from Ecuador. Here's the short version (click here to go to the campaign site for the whole story):
Someone from the Ottawa area was in Quito and saw a street puppy she liked. On her last day in Ecuador, she noticed he was looking sick. She took him to a local vet but he got worse overnight to the point that he was "barely able to hold himself up." So, she brought him home to Canada with her. I wonder about the ethics of subjecting a critically ill animal to a couple of long flights, but he managed to survive the trip and was successfully treated for parvoviral enteritis at an Ottawa veterinary hospital. The outcome’s obviously great for the dog and I can completely see how someone would do this.
However, bigger issues need to be considered:
- Why is a dog that was "adopted" not even 24 hours earlier, with no vaccination or other medical history, allowed into the country?
- Why is an obviously very sick dog allowed into the country?
- Why is a sick dog that has not been vaccinated against rabies and which can barely hold itself up (a sign that could actually be consistent with rabies) allowed into the country?
This part is not the owner’s fault. She’s not expected to know anything about rabies or any other infectious disease risks that this dog could pose (but subjecting a sick puppy to this type of journey without necessarily being able to afford the required medical care is another story).
The bigger issue is why Canada has pretty much the most lax importation requirements of anywhere on the planet. As a result we’re importing disease into the country, and really we have enough diseases of our own to worry about without bringing in more!
There was a happy ending to this story, but if the puppy was rabid (certainly not an uncommon situation in street dogs in many countries) or had some other important infectious disease, the situation could have been much worse for everyone.
Dr. Stephen Page, a regular supplier of good blog material, sent me a couple papers from the Quarterly Journal of Medicine the other day. One was an interesting report of "Staphylococcus intermedius" infection in a person, entitled "A canine bug in a human heart" (Koci et al, Q J Med 2015;108:337-338).
It’s almost guaranteed that this wasn’t S. intermedius but rather S. pseudintermedius (some medical microbiology labs are apparently still a couple decades behind in identifying this bug). Regardless, it’s an interesting case of a 58-year-old man with a pacemaker that developed fever, chills and a headache. He reported that a neighbour’s dog had licked his hand a few weeks earlier. The pacemaker incision site was unremarkable but "Staphylococcus intermedius" was isolated from two different blood samples. That's a significant concern in a patient like this because of the potential for infection of the heart valves and/or the pacemaker leads. Infections like that can be very serious and hard to eliminate (especially since we know that S. pseudintermedius tends to produce biofilm, which helps it hang around sites like pacemaker leads and avoid antibiotics). Fortunately, after a couple rounds of antibiotics and removal of the pacemaker system, he recovered.
It’s interesting (and encouraging) that the dog exposure was reported. Whether he offered the information or they asked about dog contact isn’t clear, but this is the type of information that’s often missed.
Putting this report into perspective is important. This, and various other reports of S. pseudintermedius infections, show that this dog-associated bacterium can cause disease in people.
- Single cases continue to appear in the medical literature. That means it’s really rare (since a single occurrence is enough to prompt a publication).
- The relative risk from exposure is limited. Most dogs carry this bacterium and huge numbers of people are exposed every day. So, the incidence of disease with respect to exposure is incredibly low
While "low" is good, it’s not much consolation if you’re the one with the rare but life-threatening infection. So, some basic preventative practices are indicated. Avoiding contact of dog saliva with open wounds would be one. Good general hygiene practices (especially handwashing), avoiding contact with feces and similar common sense measures are probably the key. Making sure physicians know about animal contact and think about potential zoonotic infections is also important, particularly for people who are at increased risk of infection and disease.