Spoiler alert: there’s not a lot new to say about the ongoing situation with canine infectious respiratory disease in North America. Most of this I’ve said before. Talk seems to be dying down in a lot of areas, but whether that’s because there are fewer cases or people are just getting bored of talking about it is unclear. It’s probably a combination of both. Based on some data I posted last week and talking to people on the ground in different regions, it seems like most areas that have had a (real or perceived) increase in canine infectious respiratory disease complex (CIRDC) cases are returning back to baseline. Presumably, there are some other areas where disease is ramping up, as usual. However, there are still a few questions worth bearing in mind at this stage:

Is this really an outbreak?

I’d say it’s not so much an “outbreak” as a gradual increase in the incidence of CIRDC over the past couple of years, with typical periodic spikes of disease superimposed over top of it. We have fairly clear evidence of more cases in some areas, usually following the typical outbreak pattern where cases go up, then return back to baseline levels. We also have areas where there’s really nothing too different happening.

Is there a “mystery virus” causing the increase in cases?
This is commonly reported in news headlines, but there’s no evidence of that. There’s a lot of viromics work underway, where they sequence any and all viral bits present in a sample to look for anything new. Since nothing has been found (or at least reported) thus far, it’s becoming less and less likely that there’s a new virus causing any substantial number of cases. I’d also expect a bit of a different disease pattern with a new, highly transmissible virus. More time and more testing will provide more details but at this point, I don’t think we have a reasonable suspicion of a new pathogen.

What about that strange little bacterium reported by the lab in New Hampshire?

This bug needs to be investigated more, but it’s not looking like a leading candidate at this point. It hasn’t been found to be a potential important cause of respiratory disease elsewhere (although I’ve only heard of one place that’s said they’ve looked and failed to find it). We need to learn more about this bacterium, but I’d guess that it’s either just part of the normal bacterial microbiota in dogs or it’s a potential cause of disease that’s been around for a long time, we just didn’t know (and therefore didn’t test for it). I doubt it’s a new bug that’s just recently emerged and spread in dogs in North America.

Are the reported cases of CIRCD more severe?

I don’t think so. Concerns about severe disease in dogs are probably more of a media effect. With typical CIRDC, we expect a small percentage of dogs to get pneumonia, and an even smaller percentage to have serious disease and die. That’s always been the case. When the number of dogs with CIRDC goes up, the number of dogs with severe disease will go up proportionately. So, we’d expect to see more cases of severe disease when we have an more cases during outbreaks, not because the disease itself is more severe, but simply because there’s more overall illness. If we have 100 dogs with CIRDC, we’d expect maybe 1-2 severe cases. If we have 1000 dogs with CIRDC, our severe case numbers jump to 10-20, even if the disease itself is no different.

What about treating dogs with CIRDC with Paxlovid?

Ugh. Horrible headline writing has driven requests to use this drug in dogs with CIRDC.

Please don’t.

We have inadequate dosing data and little understanding of safety for Paxlovid in dogs, and no evidence that its use is necessary (or effective) in any of these cases

What about treating dogs with CIRDC with chloramphenicol?

UGH X2. Chloramphenicol is an antibiotic. It’s a great drug, but (as for all antimicrobials) should only be used when it’s really needed. This drug has fairly important animal and human health risks (even just handling the drug), so we should not be using it routinely; however, if I have a multidrug-resistant bacterial infection in an animal, and chloramphenicol appears to be the best option to treat it, I’ll use it. Standard treatments still apply for routine cases of CIRDC. If we start using Paxlovid and chloramphenicol routinely (be it out of fear, panic or just the desire to do “something”), I have little doubt that we’ll harm more dogs than we’ll help.

Is “kennel cough” vaccination in dogs worthwhile?

Yes. We have good vaccines against canine parainfluenza virus and Bordetella bronchiseptica, two important causes of respiratory disease in dogs. Protection is much better with “mucosal” vaccines that are given directly into the nose or mouth, so that’s the kind we want to use routinely for these pathogens. The vaccines won’t protect against all types of infectious respiratory disease, but reducing the risk of some major ones is still very helpful. Intranasal and oral vaccines are given once, then re-dosed annually. There’s currently nothing indicating we should re-vaccinate dogs more frequently than this.

Are some dogs at increased risk of infection with respiratory pathogens?

Risk of infection depends heavily on risk of (and amount of) exposure. Dogs that encounter a lot of other dogs, especially transient groups of dogs of unknown health status, are at increased risk of pathogen exposure. The more dogs encountered, the closer and more prolonged the contact, and the less certain the health status of the dogs involved, the greater the risk.

Reducing the overall number of dog contacts, particularly contacts with groups of dogs of unknown health status (e.g. random groups of dogs at an off-leash park, versus a small consistent group of known dogs at a day care or play group) is an important control measure.

Are some dogs at increased risk of severe respiratory disease?

Generally yes. We know there are some dogs that have a greater risk of severe respiratory disease or death if they get infected, so we want to be extra cautious with them, including avoiding exposure, vaccination and getting them to a veterinarian sooner if the dog gets sick. High-risk dogs include older dogs, very young puppies, dogs with pre-existing heart or lung disease, dogs with compromised immune systems, and brachycephalic breeds (i.e. flat-faced breeds like bulldogs).

Why might CIRDC rates be increasing?

It’s just a guess, but we could have a pandemic-associated confluence of factors that have led to more dogs with greater susceptibility to respiratory infection.

Changes in how we have interacted over the past few years, and how often dogs go to kennels or daycare (which is often the trigger for getting a kennel cough vaccine) could plausibly have reduced overall vaccination coverage in the dog population. Also, if fewer dogs were exposed to respiratory viruses over the past few years, there may be more dogs that are susceptible to them now. I try to stay away from the “immunity debt” discussion, since that’s more political than scientific, and it’s triggering for some people (my inbox is a testament to that). Nonetheless it’s quite logical that less immune protection from less vaccination and less infection over the past couple years could mean more susceptible dogs. It’s not “debt,” it’s just deferred exposure.

From a severe disease standpoint, changes in the popularity of different dog types could be playing a role too. The French bulldog, a higher risk breed, is now the most popular dog in the US. That’s plausibly going to increase the number of cases of severe disease just based on numbers.

What should the average dog owner do?

• Breathe. This is not a doggie plague sweeping across the nation.
• Consider your dog’s risk of exposure and whether you can do things to reduce it, while not being unnecessarily disruptive to life in general (e.g. if your dog needs to go to day care for you to work, send your dog to day care).
• Consider your dog’s risk of severe disease when deciding whether to change your behaviours and how much to change.
• Talk to your veterinarian about respiratory disease vaccines.

In situations like the ongoing concern with canine infectious respiratory disease complex (CIRDC) in the US, where we don’t have any semblance of a surveillance program, we can sometimes try to piece together the picture using different data sets and observations; insurance claims can be a valuable part of this. At our webinar on canine respiratory illness earlier this week, we were able to present some preliminary data based on pet insurance claims through Trupanion. The data are biased, since insured dogs are only a small subset of the whole dog population, but they can still be informative (especially when we don’t have much else on which to go).

The full video of the webinar, along with some other resources, is available on the Trupanion website, but I’ll give a snapshot of the of the data we presented. We’re working on more and hopefully will be able to piece together a more complete story with more data over time.

Here are few interesting slides from the webinar:

This graph shows respiratory disease claims from January 2021 to October 2023:

• We’ve had a gradual but pretty impressive increase in respiratory disease claims over the past 2 years. Note that these data are adjusted for changes in insurance patterns, such as increasing numbers of dogs with insurance policies. This fits with my general observation from this time period that we’ve been seeing more disease, but not a sudden dramatic boom.
• We see general ups and downs.
• We’re at a high point now, consistent with recent concerns.

The map below is important. It shows states and provinces where there’s been an increase in respiratory disease claims year-over-year from August to October in 2022 vs 2023:

• High rates of claims were/are present in some areas where there’s been a lot of buzz.
• Some impressive increases have been seen in areas where we’ve had less buzz. I always get questions from Ontario veterinarians asking if we’re seeing more CIRDC cases, but I’d say it’s not much more lately than anytime over the past few years. Most often, I get asked “is that thing that’s going on in the US going to hit us here?” I think this map shows that we can’t just focus on media/social media reports to tell us what’s happening, because they can over-amplify issues and at the same time, some things might fly under the media radar.
• Claim rates haven’t changed in most areas, though. We’re not seeing something sweeping North America, we’re seeing patchy disease. That fits with my current guess as to what’s really going on (see details below).

Oregon’s an interesting state to look at as an example. This graph shows canine respiratory-related claims in Oregon from 2021-2023, which demonstrates a typical epidemic curve with a nice increase followed by a corresponding decrease in 2023:

• There was clearly something going on earlier this year. It didn’t seem to get much attention until it was already on the downswing, though. Talking to a few different people in Oregon, the perception seems to be that things have died down over the past month or two, and that’s consistent with the data from this graph.

This graph compares canine respiratory disease claims in California and Oregon for the last few years:

• California has had an increase in respiratory disease claim rates too, but the pattern looks different. While Oregon had a big peak and then a return to the increasing baseline, California has had a gradual but sustained (and impressive) increase over time, eventually reaching about the same rate as Oregon overall.
• Does California have more of a well-distributed higher rate of disease? Or, since California is a big state, have we had rotating outbreaks in different areas that end up looking like a steady increase? We’ll need to do a deeper dive on the data to figure that out. The graph shows that something’s going on in California too, but maybe in a different manner than in Oregon.

Let’s jump to some Canadian content. Here’s the graph of canine respiratory disease claims in Quebec from 2021-2023:

• This one surprised me. I’ve been getting questions about CIRDC cases in Quebec but nothing that stood out as unusual. (Maybe there’s more in the French-language media than I’ve been seeing.)
• The total number of claims is still relatively small, so we have to be careful not to overreact, but that’s a pretty big percentage increase.
• The time frame is also different from the Oregon peak. There’s always a bit of a lag with insurance report data, so we can’t say whether this has hit its peak in Quebec yet, or if it’s still increasing or if it’s already on its way down.
• Regardless, the pattern fits with something that’s been going on recently and is possibly ongoing. We’ll have to see how the numbers trend over the next few weeks.

When it comes to other factors that might increase insurance claims, we have to consider the influence of recent media attention. If a dog had mild respiratory disease (e.g. cough, runny eyes but eating well and otherwise pretty healthy), it might not normally be taken to a veterinarian. However, if the owner is freaked out because of all the news coverage about CIRDC, they’re more likely to take that dog to a veterinarian now versus in previous years. Those cases then end up in an insurance dataset like this (or in a testing dataset from a laboratory) because of owner factors, not dog or disease factors. One way to help tease this out is to look atmore expensive claims, or claims that involve things that would only be done on sicker dogs (eg. oxygen therapy). Our preliminary look at those data showed similar but more blunted trends in terms of increases in some areas, gradual increases over time overall, and no change in most regions. So, the increases we’re seeing in overall claims are probably pretty reflective of true changes, though likely with some fear-driven (vs disease-driven) increases.

Other things we need to consider are what types of dogs seem to be over-represented, beyond regional effects. Preliminarily, claims involving brachycephalics (squish-nosed breeds) seem to be significantly more common, which isn’t overly surprising as these dogs may have less tolerance of any form of respiratory disease. More to come on that.

What’s driving severe disease is also really important. Mild respiratory disease isn’t ideal, but we’re more worried about pneumonia and severe illness that can make dogs really sick, result in high veterinary bills, and kill a small percentage of dogs. Brachycephalics, senior dogs and dogs with pre-existing heart or lung disease are probably at higher risk for severe disease, but we need to look at the data more to confirm that.

Where does this take us?

As we get more data, look at disease patterns over time and locations, and talk to more people about what they are seeing, I’m increasingly convinced that this is a situation of the usual suspects (our normal CIRDC pathogens) doing their usual thing (mild disease in most dogs with a small subset that get pneumonia and a small subset that get really sick), but at a higher rate. I think the rate has been increasing for a while, which makes the normal ups that we see with waxing and waning disease more obvious. I think it’s clear that we’ve had true increases in disease in some areas, but not all, and that clusters are following the typical course of “what goes up, comes down.” Media attention is amplifying the concern, so that we’re hearing more about a lot of things we wouldn’t normally, but there’s a true disease underpinning to those reports.

Why? What is driving the increase in disease rates?

The “why” is unclear, since we still don’t really know the “what” well. When I think about what drives increased disease, I focus on dog factors and bug factors. We have various logical reasons why this increase could be driven largely by dog factors. For example, in the past few years, we’ve seen:

• More dogs
• Disrupted veterinary care (less vaccination)
• Changes in human activities (e.g. more remote work, maybe leading to fewer dogs at day care and therefore less kennel cough vaccination)
• Other changes in human activities that alter how dogs interact
• Changes in the types of canine respiratory disease vaccines we use
• Earlier pandemic restrictions reducing the normal level of exposure to kennel cough pathogens and vaccination

The net result would be an increase in dogs with less immunity from vaccination or previous infection.

For bug factors, I think about the possibility of:

• A new pathogen
• An existing pathogen that’s changed

We don’t currently have any clear evidence of either of these bug factors. The story about a previously unknown small bacterium that has been found by the New Hampshire veterinary diagnostic laboratory is still worth investigating, but at this point it’s not clear that it’s driving anything. If this bug turns out to be a pathogen in dogs, most likely it will be a “new to us pathogen” versus a “new pathogen” scenario. By that, I mean that it’s more likely that it’s a longstanding cause of disease that we’ve never diagnosed before, versus a new bug that’s recently emerged and is starting to spread. The current disease patterns don’t really fit with emergence of a new highly transmissible pathogen.

I’m open to new evidence and other opinions, but at this point, if I had to make a somewhat informed guess, I’d go with the assumption that we have patchy but significant increases in disease in some areas across parts of North America, but driven by our normal bacterial and viral causes.

We also have to avoid over-interpreting the insurance claim data, since it’s just one piece of the puzzle, albeit a potentially important one. Everyone always wants definitive answers “now,” but that’s not how outbreaks or outbreak investigations go (especially outbreaks in dogs where we have almost no funding for formal surveillance or analysis of any kind).

Dr. Mike Lappin and I are teaming up with Dr. Carrie Jurney (President of Not One More Vet) and Dr. Steve Weinrauch (Chief Veterinary/Product Officer of Trupanion, founder of MightyVet) for a webinar about canine infectious respiratory disease complex (CIRDC) issues in the US (plus some Canadian content). There may be a lot of “we don’t know yet” comments, but we’ll have some insights, some reasonable guesses and, yes, a bit of new data about the situation.

Disclaimer: This webinar is coordinated by Trupanion, a pet insurance company, but it’s a non-commercial talk, and we’re not being paid to do it. We’re just hoping to get some good information out to a broader audience by making use of Trupanion’s interest and reach.

Here are the details about the webinar and how to join:

Trupanion is inviting pet parents and veterinary professionals to join a free, live webinar – “Separating Fact, Fiction, and Uncertainty: Canine Respiratory Illness Q&A” to be held Thursday, November 30, 2023, at 4:30 PM PT / 7:30 PM ET.

This timely event will include: 

• REAL-TIME UPDATES: Stay informed with the latest updates on canine respiratory illness, leveraging Trupanion’s database of over 3 million Trupanion-protected pets.
• PREVENTION STRATEGIES:  Learn effective strategies and practical measures you can take to safeguard your pup’s health.
• SIGNS TO WATCH FOR: Learn how to recognize early signs, empowering you to take proactive steps to address potential concerns.
• LIVE ANSWERS TO PARTICIPANT QUESTIONS: Participants can engage directly with the panel of experts to ask questions about canine respiratory health.

EVENT DETAILS:

• Date: November 30, 2023
• Time: 4:30pm PT / 7:30pm ET
• Location: https://k9illness.trupanion.com/

FEATURED SPEAKERS:

• Panelist | Dr. Scott Weese: Dr. Scott Weese is a veterinary internist, a Diplomate of the American College of Veterinary Internal Medicine, and a Fellow of the Canadian Academy of Health Sciences. He is a Professor at the Ontario Veterinary College, University of Guelph, Director of the University of Guelph Centre for Public Health and Zoonoses, Chief of Infection Control at the Ontario Veterinary College Health Sciences Centre, and is a member of numerous national and international committees dealing with infectious diseases and antimicrobial resistance, including the Quadripartite (WHO, WOAH, FAO, UNEP) Global Leaders Group on AMR. 
• Panelist | Dr. Michael Lappin: Dr. Michael Lappin is a veterinary internist, a Diplomate of the American College of Veterinary Internal Medicine, holds a PhD in Parasitology, is Director of the Center for Companion Animal Studies at Colorado State University School of Veterinary Medicine and Chair of the World Small Animal Veterinary Association One Health Committee. He is also currently a Professor at the College of Veterinary Medicine and Biomedical Sciences at Colorado State University. 
• Special Guest | Dr. Carrie Jurney: Dr. Carrie Jurney is a veterinary neurologist and practice owner at Remedy Veterinary Specialists in San Francisco. She is a passionate advocate for mental health and wellbeing, and serves as the president of Not One More Vet 501(c)(3), the world’s largest wellness-focused charity for veterinary professionals. 
• Host | Dr. Steve Weinrauch: Dr. Steve Weinrauch, BVMS, MRCVS is the Chief Veterinary/Product Officer of Trupanion and founder of MightyVet 501(c)(3). Before joining Trupanion, Steve built and ran three veterinary practices in the Seattle area. He has published his research in numerous peer reviewed journals, and he is licensed to practice in both the U.S.A. and the European Union.

Please note: the webinar recording will be available for on-demand viewing at https://k9illness.trupanion.com/

There’s been a lot of discussion about canine infectious respiratory disease complex (CIRDC) going around in dogs in the US recently. In the last week, I’ve already covered this from a few different angles, including what might really be going on with all the reports of sick dogs, reports of the potential involvement of a potential novel canine respiratory pathogen and when and when not to treat dogs with respiratory disease with antimicrobials. I’ll try to get another post done soon about the data we have (and don’t have). This post will address the most common questions dog owners are asking.

What should dog owners do?

Relax. It seems like there’s more respiratory disease in dogs in some areas, but that’s something we often see. Serious disease is being reported in a small subset of infected dogs, but that’s also something we regularly see. So, being aware is good, being anxious is bad, freaking out is definitely unnecessary.

The vast majority of dogs that get CIRDC recover uneventfully. That’s as true now as it was a year or 10 years ago. However, severe disease can occur so we don’t want to be too dismissive.

My dog is sick. What should I do now?

The default answer is “talk to your veterinarian if you’re concerned.”

However, the answer is not “if your dog coughs, it must be taken to a veterinarian ASAP.” A dog should be taken to a veterinarian if it’s really sick, deteriorating quickly, not getting better over the course of several days (but remember dogs may still cough after they’re feeling better), if there might be complications, or if it’s unclear what’s going on.  If the dog just has mild upper respiratory infection, it rarely needs to be seen by a veterinarian. If it has pneumonia, it definitely needs to see a veterinarian.

Think about it in terms of how we react when we get sick or our kids get sick. If you had a cough and felt a bit run down, you probably wouldn’t go to a doctor unless you had underlying risk factors for severe disease. The same applies to dogs – if they’re pretty bright and alert, are eating and breathing normally, but just have a cough and runny nose or eyes, it’s very unlikely they need to be examined (in part because it’s very unlikely that they need any specific treatment or testing, and because a visit to the veterinary clinic might just cause more stress for the dog and risk exposing other animals.) If you felt like you could barely drag yourself out of bed or you were having a hard time breathing, you’d go to the doctor. That’s also the same for dogs.

While I want to avoid being too prescriptive about who should or shouldn’t see a veterinarian (since there are lots of exceptions and grey areas), if the following signs are present, a prompt visit to the veterinary clinic is indicated:

• Weakness, severe depression (meaning the dog is really quiet, not engaged and just lies around, doesn’t get up when you’d expect it too (like for food))
• Loss of appetite
• Difficultly breathing (breathing faster and harder even when not exercising)
• Rapid worsening of illness
• Cough that is causing significant problems such as vomiting or making it hard for the dog to breathe

It’s especially important to see the veterinarian if these signs occur in a high-risk dog, including:

• Elderly
• Very young
• Pregnant
• Immunocompromised (by disease or treatment)
• Underlying heart or respiratory tract disease
• Brachycephalic (i.e. squishy-faced) breeds

What will happen when I take my dog to the veterinary clinic?

That’s depends on a lot of things, so it’s hard to say what you should expect.

• The first thing the staff should do is assess whether it looks like your dog has infectious respiratory disease, and how stable your dog is (in terms of its lung function). Most dogs with CIRDC don’t need anything but time and TLC; so, if your veterinarian says your dog looks stable and no treatment is needed at this point, take that as a good sign. Don’t ask for unnecessary treatments like antimicrobials “just in case.”
• If your dog’s cough is disruptive, then a cough suppressant may be warranted (but that depends on a few things).
• If your dog has signs of pneumonia, radiographs of the chest and bloodwork will likely be needed. If pneumonia is confirmed, antimicrobials are indicated.
• If your dog is really sick, hospitalization with intensive care, antimicrobials and oxygen therapy may be required. That’s uncommon but it happens, and when there’s more respiratory disease activity in an area at a given time, there will be more cases of severe disease too just based on numbers (e.g. 1% severe disease rate in 1000 infected dogs is more really sick dogs than 1% in 100 infected dogs).

The severity of your dog’s illness, the type of illness, what the clinic can offer and (unfortunately) sometimes budget limitations will influence what’s ultimately done.

Additionally, sick dogs should be kept away from other dogs to help reduce the risk of disease transmission. That includes no going to day care, parks or any other places where non-household dogs would be encountered. For how long? That’s hard to say without a diagnosis but I’d aim for at least 2 weeks.

My dog is healthy. What should I do?

Let’s try to keep your dog healthy by limiting its contact with other dogs, especially large numbers of different dogs with unknown health status. Contact with small, stable groups (e.g. an established walking group, a small day care with the same dogs that don’t see a lot of other dogs) is lower risk. Logically, dogs should be kept away from any obviously sick dogs.

What about vaccines for my dog?

Vaccines are available for some of the causes of CIRDC. For any dogs that have frequent contact with other dogs, vaccination against Bordetella bronchiseptica and canine parainfluenza virus is important. Mucosal vaccination (intranasal is preferred, oral is second best) should be done whenever possible. Critically, it is important to use a vaccine that covers both Bordetella and parainfluenza. I suspect that loss of parainfluenza protection because of increased use of Bordetella-only oral vaccines might be driving some of the issues we’re seeing.

Canine influenza (flu) vaccination can be considered too, but it can be hard to get (there are currently some production and backorder issues) and canine flu is a pretty sporadic disease.

My dog is healthy but higher risk for disease or complications (see high risk list above). What should I do?

Take the same precautions described above for non-high risk dogs, but with more rigour. I’d also be quicker to recommend respiratory disease vaccines for these dogs, irrespective of how much contact they have with other dogs.

My own two dogs probably fall into those two risk categories. Both have fairly cloistered lifestyles from an exposure standpoint. Their dog contacts are largely restricted to a small number of well known and similarly low risk dogs.

The young pest, Ozzie, is a one-year-old, healthy Labrador, and is therefore at low risk of exposure and low risk for serious disease. He got an intranasal Bordetella/parainfluenza vaccine this summer so he could go to day care when we were away at a cottage (to give us some Ozzie-free afternoons to relax). The old guy, Merlin, is an 11-year-old Labrador who’s on chemo for chronic lymphoid leukemia. His exposure risk is low but he’s probably at some degree of greater risk for serious disease if he gets infected. There doesn’t seem to be anything remarkable going on locally compared to normal, so it’s status quo for them, but I’d be quicker to vaccinate Merlin if I decided vaccination might be warranted, especially if influenza hit the area.

As with any emerging issue, the current situation in the US is fluid, and we’re trying to sort out more about what’s happening. At the moment, for your average dog owner, it’s still just a matter of some common sense precautions and good dog care.

As concerns about an outbreak of canine infectious respiratory disease in the US continue, we’re still at a point where media hype massively outweighs any true data. Not much new has been reported recently. If anything, I’d say we’re hearing more about things being stable in different areas, that investigations haven’t turned up anything beyond the usual suspects, and the typical messaging to use common sense but relax.

One thing that is getting some press is a suggestion that a rather bizarre little bacterium might be involved in some of the current canine illnesses. “Might” is the key word though. At the risk of having to eat my words later, I’d guess this bug is probably not going to pan out to be a driver of widespread disease – it’s possible, but there’s a long way to go before we can say that with any confidence. In the meantime, let’s recap what we know:

In the spring of 2023, the New Hampshire Veterinary Diagnostic Lab reported they were investigating a potentially novel organism as a cause of respiratory disease in dogs. I remember reading about it in a taxi on my way to the airport in DC; I thought it was interesting, but in my experience, the vast majority of “new pathogens” end up being commensal organisms (i.e. also present in lots of healthy dogs) or otherwise not panning out to being relevant. But, I never totally discount the possibility, and was glad to see it investigated. The initial (and I think only) report involved a pretty small number of dogs. They found snippets of DNA that were similar to IOLA KY405 in 21/31 samples. Their latest update is here.

What on earth is IOLA KY405?

It’s hard to say. As far as I know, it’s only previously been reported in two papers from the same lab in Japan, where it was found in samples from humans with respiratory disease. It’s reported to be a bacterium with a very small and bizarre genome.

• The first study (Fukuda et al. 2014) reported finding gene sequences from IOLA KY405 in a lung fluid sample from one person, then followed up by finding those DNA bits in samples from 6/386 samples from other patients with respiratory disease. Some unique aspects of this bacterium are a very small genome, similar to Mycoplasma  (just over 300K base pairs; for reference, staphylococci have about 2.8 million base pairs), and a very high AT content (about 80%).

• In the second study (Fukuda et al. 2021), they presented the whole genome sequence of the organism. They also used PCR to look for it in samples from more people with respiratory disease, and got positive results in 2.7% of about 500 samples. Eight of the 11 positive patients had significant underlying disease, and five were being treated with corticosteroids or immunosuppressants. So, these individuals had lots of other excuses to have respiratory disease or to be infected with something that’s minimally pathogenic.

Someone with more background in genomics would need to assess the papers to know how confident we can be in the results. If they are real, then the researchers have found a small bacterium that’s similar to Mycoplasma, which maybe isn’t surprising since some Mycoplasma are able to infect lungs (but more often are present as normal respiratory tract inhabitants.)

What we’re still lacking is 1) actually growing the bug to confirm its existence, and most importantly, 2) context. Finding DNA from this bug in a small percentage of people with respiratory disease is interesting, but could it be just as common in healthy individuals and just part of our normal microbiota? I don’t think we can say either way at this point.

When something’s only reported by one group over a long period of time, it raises the question of why. Is one group just way ahead of the curve, or is this something that other people have tried to find but have been unable to replicate the results (or have looked at and dismissed as not being worth investigating)? Publication bias is a big problem in cases like this. If other groups have put in a good effort to investigate this and found nothing, odds are high we wouldn’t find out because there’s a tendency to not publish “negative” results, even though those data are really important. So, we have no idea if there are only two papers because only one group is looking for it, or whether lots of other people have tried and failed to find anything similar.

Genome-based pathogen discovery is an established and effective method. It looks at all the genetic bits we can find in a sample, then tries to assemble them into something interpretable, and then we try to figure out what it actually all means. It’s challenging because we have a vast population of viruses and bacteria that are normal inhabitants in our bodies and those of animals. Most are harmless. Many are beneficial. Some can cause disease. Sorting out into which category a new organism fits takes a lot of work, and is rarely straightforward.

We’ve been lead down the wrong path many times before by reports of a “new” organism found in sick animals (e.g. the panic about canine circovirus). People freak out, start testing more sick animals, find it, and freak out more. However, when the science catches up with the hype, we often realize that we can find the bug in the same percentage of healthy animals, and it’s just a normal inhabitant that we’ve recently discovered, versus something new that is causing disease. With modern molecular techniques, our ability to find something often surpasses our ability to understand it.

While it sounds like I’m downplaying the relevance of this finding, that’s not my intention. I suspect IOLA KY405 is a real organism, I just need a lot more convincing that it’s relevant to disease (in people or animals). In an ideal world, the New Hampshire lab and others would be investigating this robustly, including field studies in dogs, to deterimine what the real story is. Lack of funding for companion animal infectious disease research usually slows these to a crawl. The report from the New Hampshire lab adds good context:

• “It is important to note that this is a preliminary finding, and under normal circumstances of a study we would not release these findings. The technology and methods used by the HCGS include cutting edge metagenomic sequencing, and multiple bioinformatic pipelines that are uncommonly utilized in veterinary medicine. Additionally this is an uncommonly studied group of bacteria. There are multiple experiments that need to be run in order to clarify correlation vs. causation, and this gives reason for pause in releasing the findings. However, the syndrome is ongoing and there may be an opportunity to benefit animal health as we continue to validate these initial findings. There is a chance that this preliminary data is disproven with further study, but at this point it does appear that the bacteria we have identified is a potential causative agent.”

Those disclaimers are key, but unfortunately are usually left out of the media reports.

This is an important but very preliminary finding that needs to be studied. However, we also have to realize that most findings like this don’t turn out to be anything big (or anything at all). We can’t dismiss the potential and it’s great to see the work being done, but we need to make sure that we don’t jump from a preliminary finding of some unusual DNA sequences to “here’s the answer!” which is what human nature wants us to do.