Antimicrobial resistance (AMR) is a big problem with a crappy marketing plan. It’s been termed a “silent pandemic,” and it has huge health and financial impacts that are only going to get worse if we don’t act. Unfortunately, even though we’ve been battling this issue for decades, the average person doesn’t know about it, or doesn’t care (mainly the former), and the lack of awareness leads to lack of motivation for both individual action and broader action to combat the problem.

We don’t hear about AMR during election season. In fact, we probably lose traction on AMR around election time because the general public doesn’t care (or they just care more about other things), but some interest groups do. If you’re a politician and you realize that something isn’t on the radar for average voters, but measures you’d take to address it cost money and might create friction with certain groups, you’re unlikely to act, and you’re particularly unlikely to take the ambitious steps that we need to address a wicked problem like AMR.

We need everyone to have a better understanding of why AMR matters and why we need to invest time, effort and money.

TLDR? AMR kills a lot of people, costs us billions of dollars every year, and has a major impact on the global economy. There are parallel issues with AMR in animals.

Here are a just a few more details:

Impact of AMR in humans

A few weeks ago, an updated assessment of the global burden of AMR on humans was released (Naghavi et al. 2024). The results weren’t too surprising to those of us in the field, but the numbers should (hopefully) shock people who haven’t been in the loop:

  • In 2021 alone, an estimated 1.14 million deaths were “directly attributable to AMR”*. That’s one death approximately every 30 seconds.
  • An estimated 4.7 million deaths were “associated with AMR”*.
  • Annual deaths increased minimally between 1990 and 2019, but are expected to start increasing.
  • By 2050, 1.9 million deaths globally could be directly attributable to AMR every year, with 8.2 million deaths associated with AMR.
  • AMR deaths in young children have decreased while deaths in individuals over 25 years of age have increased since 1990 (see Figure 4 from the paper, below), but children less than 5 years of age were still disproportionately affected. It’s particularly severe in sub-Saharan Africa, where 59% of deaths attributable to AMR were in children less than 5 years of age.
  • Deaths from 12 AMR pathogens decreased while deaths from 12 others increased. Streptococcus pneumoniae had the biggest decline while Staphylococcus aureus had the biggest increase.
  • The top 6 pathogens, all of which accounted for >100,000 deaths each, were S. aureus, Acinetobacter baumannii, E. coli, Klebsiella pneumoniae, S. pneumoniae and Pseudomonas aeruginosa (see Figure 5 from the paper, below).
  • Methicillin-resistant S. aureus (MRSA) boomed, going from 57,200 attributable deaths in 1990 to 130,000 in 2021.
  • Klebsiella pneumoniae, S. pneumoniae and E. coli had the biggest burdens in children.
  • Among specific drug/bug combinations, MRSA, multidrug-resistant tuberculosis (TB), carbapenem-resistant K. pneumoniae and carbapenem-resistant A. baumannii had the biggest impacts.
  • Using a “better case scenario,” they estimated that 92 million deaths between 2025 and 2050 could be cumulatively averted with better healthcare, better treatment of infections and improved access to necessary antimicrobials.

* “Attributable to AMR” is based on the outcome of a resistant infection compared to an equivalent susceptible infection. “Associated with AMR” is when resistant infections are compared to no infection.

Impact of AMR in animals

We don’t have as much information about the impact of AMR in animals vs humans, and it’s a really complex area. However, some of the issues are outlined in a recent report by the World Organisation for Animal Health (WOAH) and a group of collaborators, entitled Economic Impacts of AMR in Food-Producing Animals.

If we don’t take further action to curb AMR now, it’s estimated that it will have the following impacts:

  • By 2050, the loss of livestock production from AMR will equal the consumption needs of 746 million to 2 billion people per year.
  • A cumulative global gross domestic product (GDP) impact (loss) of $575-953 billion USD between 2025 and 2050. When considering the impact of AMR in animals and spillover impacts on humans, the impact on global GDP would be $1.1-5.2 trillion USD for the same period.
  • Conversely, a “reasonable” AMU reduction (30%) globally could increase the global GDP by $120 billion USD between 2025-2050.

Also, these figures doesn’t include AMR in companion animals. There are substantial impacts of this issue in pets too, including illness, increased treatment costs, an unknown but not inconsequential number of deaths, and corresponding impacts on animal welfare and the human-animal bond.

We need to pay attention more attention to AMR. AMR is too easy to dismiss or not think about, perhaps because it’s not as in-your-face as other issues that affect the daily lives of the public, and doesn’t lend itself to flashy media stories. But for something that kills millions of people, it doesn’t get enough attention. Inadequate attention leads to inadequate action. It’s time to act.

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Bats are getting a lot of attention around here following the recent death of a person in Ontario from rabies. The infection was “suspected to have been acquired from direct contact with a bat…” Most rabies deaths that occur in North America nowadays are due to transmission from bats, but all too often the risk of contact with a bat isn’t recognized. If a person is exposed to rabies through contact with saliva from an infected bat and post-exposure treatment isn’t given promptly, the outcome can be tragic.

Rabies is endemic in bats throughout North America – wherever we have bats, we have rabies. We don’t know the exact percentage of bats in the general population that are infected, but ultimately it doesn’t really matter – whether it’s 0.1%, 1%, 10% or more, it’s in all our bat populations. Any one bat could be infected (and you can’t tell just by looking at the bat, or its behaviour), and therefore any bite from a bat could transfer rabies virus to a person (or other mammal).

One of the major issues with rabies in general but especially when it comes to bats is the general public’s understanding of the risks. Bats in particular have tiny teeth (and they can move very fast!), so a little bat bite might not be noticed. Even if the bite is noticed, there’s so little trauma that a person could easily dismiss it, and wouldn’t seek care like they might for a bite from a larger mammal. But we need people to understand that even a tiny bite from a high-risk species like a bat can transmit rabies. Any contact with a bat that could have resulted in a bite needs to be investigated promptly so post-exposure treatment can be given when necessary to stop the virus before it can cause infection.

But determining the level of risk is sometimes still really hard.

  • If a bat is lying on sidewalk and you pick up (note: please never do that!) and you feel a bite: That’s clearly exposure.
  • If a bat flies into your house when you open the door, does a little tour, and then flies back out: That’s clearly not exposure.
  • The problem is the big grey area in between.

In Ontario, prior to 2008, waking up in a room with a bat was considered a potential exposure based on the premise that you could be bitten but not notice if you were a asleep. That’s the situation I ran into we had a rabid bat in our house back in 2008. Because the bat had likely been in the house for a few days (and everyone had been sleeping at some point), everyone got rabies post-exposure prophylaxis (PEP). Shortly after that, the guidelines changed based on the very low risk posed by that type of situation and the healthcare burden of the massive number of people that received PEP (unnecessarily) for that reason.

Now, there is a more complex risk assessment for bat exposures (see below), and sleeping in a room with a bat does not automatically mean PEP is indicated. If in doubt, the default is typically to give PEP, because rabies is so deadly and PEP is incredibly effective. However, it’s not indicated in most situations when a bat is in the house and there’s no evidence of direct contact. That can be tough messaging to communicate in the moment though, especially when kids are involved.

We don’t want to eradicate bats.

  • They are important parts of the ecosystem (especially for controlling insect populations!).
  • Several bat species in Ontario are actually endangered.
  • It’s not their fault they are rabies reservoirs.
  • Please beware but be kind to bats!

We can’t eliminate rabies from bats.

We can’t eliminate the risk of a bat being rabid.

  • Not all rabid bats look sick or act abnormal.
  • Bats can’t be tested for rabies while they’re still alive, because the brain needs to be sampled.

We CAN essentially eliminate the risk of rabies from bats in people with some basic measures.

A lot of that revolves around public awareness. The key points are:

  • Stay away from bats.
  • Discourage bats from roosting in buildings; seal up any tiny holes they might use to get into a building.
  • If a bat gets in your house, open as many doors and windows as you can to let it fly back out (the bat doesn’t want to be in your house either!)
  • If you do have direct contact with a bat (despite efforts to avoid it!), talk to public health to see if rabies PEP is indicated. Look closely for any marks on the skin that might indicate a bite, but don’t dismiss the possibility if you don’t see anything.
  • If you wake up and find a bat in the room, talk to public health to see if rabies PEP is indicated.
    • In either of these cases, if the bat or its remains are available, it may be possible for public health to arrange to have it tested to definitively determine if rabies is a risk. But bats should not be killed or euthanized just for testing if it’s not clearly necessary!

The most important point is recognizing there’s a rabies risk from bats and that anyone with potential contact with a bat should engage public health. Rabies is almost completely preventable if we take the right steps, but if people don’t realize the risk and know what to do, we miss the chance prevent this horrible disease.

The recent death was tragic. Hopefully some good will come from it in the form of more awareness.  

Also don’t forget that pets can also be exposed to rabies if they have direct contact with a bat! If your pet catches, plays with or otherwise touches a bat, be sure to contact your veterinarian for a risk assessment (even if your pet is currently vaccinated for rabies), in case additional action is needed to protect your pet and you!

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Outbreaks of human salmonellosis linked to reptiles are far from rare or noteworthy, but since they’re still common, clearly we still need to talk about them to help increase awareness.

The latest such outbreak in Canada involved 25 cases of Salmonella Muenchen infection in people linked to contact with geckos. Cases stretched from British Columbia to Newfoundland, with stops in Alberta, Manitoba, Ontario, Quebec and Nova Scotia, but most of the cases (13/25) were in Ontario. It’s been a slow going on at a slow burn for a while now, with infections dating back to August 2020 and right up to September 2024 (and probably beyond). The outbreak “curve” is shown in the graph below.

As ever, it’s safe to assume the 25 reported infections are a small minority of the actual number. To get included in the case count, a person has to get sick, and then go to the doctor and get a fecal sample tested for Salmonella. That usually doesn’t happen in mild cases, so if 25 were severe enough to be reported, there were actually probably a couple of hundred people who got infected.

The age range of patients in this outbreak so far is 1-103 . People at both ends of that range are more likely to get severe disease from something like Salmonella, but people of any age or health status are susceptible to this bacterium. Children tend to take the brunt of reported illness, likely in part because of some of their behaviours lead to increased exposure, because disease can be more severe in young kids, and because they may be more likely to be taken to the doctor to get diagnosed. Three people in this outbreak were hospitalized and one died. We don’t often see deaths in these Salmonella outbreaks, but they can definitely occur.

Detailed exposure information hasn’t been released but many affected people reported direct contact with geckos. Since most people in the population don’t have regular (or any) contact with geckos, that makes a strong link between this outbreak and gecko contact. Additionally, some people had been in the same house as a gecko, even though they didn’t handle the animal. My line is “the gecko may stay in its terrarium but Salmonella won’t.” There are lots of instances of people (especially infants) getting Salmonella with no known direct contact with the presumed source reptile. That’s because people track Salmonella out of the terrarium after handling the animal or terrarium contents, or by doing things like rinsing out food or water bowls in the kitchen sink and cross-contaminating items that then come in contact with other people (or their food).

This outbreak doesn’t change any of the risks or any of the messaging. Keep high risk people away from reptiles, including kids less than 5 years of age and adults over 65 years of age, as well as anyone who is pregnant or immunocompromised. That includes avoiding both direct handling of reptiles and being in households or other areas where they are housed.

Testing reptiles isn’t a way out of this problem either. We can test reptiles to see if they are carriers, but a single negative test doesn’t mean there’s no risk. They can test negative today but positive tomorrow, and I’d never say there’s no risk from a reptile, even if it’s tested multiple times.

I’m not against reptiles, I’m just against having them in high-risk households because it’s clear that they cause disease. It’s not common, but it’s likely massively underdiagnosed. There’s no denying that every year, many people get sick (and a few die) from Salmonella acquired from reptiles.

We don’t have a specific fact sheet for geckos, but the information about risks from turtles (and how to mitigate them) generally apply to geckos and other reptiles as well. Check out the factsheet on turtles on the Worms & Germs Resources – Pets page.

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A tragic case of rabies in a person in Ontario was reported earlier this month. Very few details about the case have been released publicly, other than the person was exposed to a bat in Ontario and became progressively ill, later being admitted to hospital with clinical signs of encephalitis and symptoms consistent with rabies.

The case is a tragedy particularly because we have the means in Ontario to prevent this fatal disease in people. The three most important components of rabies prevention are:

  1. Avoid contact with wildlife. Rabies is not transmitted through the air or the environment, it is transmitted through direct contact with saliva (or neural tissue) from an infected mammal. Enjoy wildlife from a distance. Rabies is just one of many reasons why contact with wildlife (or any unfamiliar animal) is a bad idea. This is especially important when it comes to bats, because they are a high risk species for rabies, but also an incredibly important part of many ecosystems, and many bat species in Ontario are also endangered – so please beware, but also be kind to bats!
  2. Sometimes despite our best efforts, contact with wildlife occurs anyway. When this happens, it’s important to have a risk assessment done to determine if post-exposure prophylaxis (PEP) is needed for people (or other post exposure management for domestic animals). Rabies PEP is almost 100% effective at preventing infection IF it is given in a timely manner. Not every animal encounter warrants PEP, but when it does, it’s important to start the shots right away. Human exposures should be assessed by public health, and domestic animal exposures should be assessed by a veterinarian.
  3. Vaccinate pets. In Ontario, vaccination of dogs, cats and ferrets over 3 months of age every 1-3 years is required by law. Although the rabies reservoir species in Ontario are all wildlife (bats, skunks, raccoons and foxes), pets are a major bridge between wildlife and people, because they often have close contact with both. Keeping pets vaccinated helps prevent wildlife from infected them, and in turn keeps pets from infecting people.

Despite the best efforts of public health staff, veterinarians, conservationists, educators and so many others, there are still so many people in Ontario who do not realize the risks associated with wildlife contact – particularly from a tiny bat that seems so harmless at first glance – and what to do when contact does occur. So this case is an important reminder to everyone that rabies is real, and it is still a risk even when we haven’t had a domestically acquired case in Ontario for decades. Tell your friends, tell you neighbours, tell your kids – make sure everyone knows, so we can help prevent the next tragic case.

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In some ways, I wonder why there even are recalls for raw pet foods and Salmonella. We know contamination is common, and the contaminated foods that get identified and recalled are presumably a very small portion of the amount of contaminated food that’s in circulation. At the same time, when a problem is identified and the FDA asks for a recall, I find it astounding that a company would ignore that.

Darwin’s Natural Pet Products is in the news yet again for selling contaminated raw pet food – and ignoring an FDA request for a recall.

As a result, the FDA has issued a public notice regarding Darwin’s Natural Selections Pet Food:

  • The U.S. Food and Drug Administration is cautioning pet owners that FDA samples of five Darwin’s Natural Pet Products raw cat and dog food made by Arrow Reliance, Inc. tested positive for Salmonella and a sixth FDA sample tested positive for Salmonella and Listeria monocytogenes (L. mono). 
  • The FDA recommended that Arrow Reliance, Inc. recall all six lots of product. To date, the firm has not recalled the affected products and could continue to distribute them. Therefore, FDA advises consumers to keep checking Darwin’s Natural Selection Antibiotic & Grain-Free products for the affected lot numbers prior to feeding to pets.

I could make a crack about Darwin’s “natural selection” but would rather the company just be responsible, recall their products and review their practices, to reduce the human and animal health risks.

Cleaning up some of the misinformation on their website would be good too, like where it suggests Salmonella is only a risk to puppies and kittens less than 4 months of age, or to those that are immunocompromised. Salmonella can most definitely cause disease in healthy adult dogs and cats, as well as their owners.

For more information about raw diets, including the risks and how to reduce them, see our recently updated Raw Meat Diets infosheet (produced in collaboration with OAHN) on the Worms & Germs Resources -Pets page.

Following up on a recent post regarding evidence for shortened duration of treatment in select cases of feline infectious peritonitis (FIP), we have a new WormsAndGermsPod quick-bite on FIP treatment duration.

This short 14-minute podcast covers:

  • If/when can we shorten the duration of antiviral treatment for FIP
  • The issues to consider
  • The data (old and new) we have available

Check it out on Apple Podcasts, Spotify and most common podcast directories, or click here to go directly to the podcast in your web browser.

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A lot of infectious disease events get over-hyped by the media, which makes it a bit surprising that this case has flown a bit under the radar. It’s not a sign of an impending “influenza apocalypse,” but it’s a warning sign that more may be going on lately with flu viruses than we’ve been able to observe directly.

The CDC has confirmed a case of H5 influenza infection of a person in Missouri who had no reported contact with animals of any kind. The virus has only been identified as H5 or H5Nx, which means they have not confirmed the N-type, so we can’t say if it’s the same as the H5N1 influenza that has been circulating in wild birds since 2022, or in dairy cattle in the US since spring 2024. It’s surprising that the N-type has not been determined yet, since the infection was detected over 2 weeks ago – but knowing the strains that are circulating in the US right now, I’d say it’s almost certainly H5N1. (Sometimes sample quality can impede the effectiveness of molecular diagnostics too.)

Human H5N1 infections linked to the ongoing massive multiyear avian influenza outbreak have been rare. There have been just 14 reported H5 infections in people in the US so far in 2024, despite a huge amount of potential exposure, particularly among livestock and poultry workers. All previous human infections have been linked with direct and close contact with infected animals.

Rare spillover infections like these are largely expected when there’s lots of disease in animals. The worry is the potential for the virus to change to become amenable to human-to-human spread, so finding a human infection like the one in Missouri with no direct link to animals raises a lot of concern. The source of exposure in this case has not been determined. Details are sparse, but the person was reportedly hospitalized and recovered, and H5N1 testing was done as part of ongoing surveillance.

How could a person get H5N1 without animal contact?

  • Unreported animal contact, possibly due to incomplete history taking, or poor recall or unwillingness to report contact on the part of the patient for some reason)
  • Contact with a surface contaminated by an infected animal
  • Ingestion of contaminated food products

We hope the source of infection in this case was one of those. Hopefully they queried all animal contacts, not just birds and cattle, since we’re also concerned about infection from susceptible species that can bridge bird, cattle and and human populations (particularly cats).

Otherwise, we get concerned about the last option:

  • Contact with another infected person

As has been pretty common, details have been slow in being released. More information is needed about the person’s history, including whether the person had any human contacts that were high risk for exposure (e.g. worked with infected animals), and the genome of the virus to see if it’s consistent with the circulating avian strain, the strain that jumped to dairy cattle, or something different, and whether the strain has any genetic markers that indicate it could be more adept at spreading person-to-person. Missouri hasn’t reported H5N1 in cattle, but it’s circulating in wild birds, with spillover into poultry and backyard chickens. Missouri doesn’t have a huge dairy industry, but there are still lots of dairy cattle around and it doesn’t sound like there’s been much testing (a report in July said that only 17 of the state’s approximately 16,000 dairy cattle had been tested), so we can’t rule out local dairy cattle (or unpasteurized milk) as a source either.

Hopefully this is an oddball infection that died out when the person recovered, i.e. they got infected somehow but didn’t pass it on to anyone else. However, even if that’s the case, this event demonstrates why we need to have comprehensive and nimble influenza surveillance.

  • If the infection is indirect linked to dairy cattle (by finding the dairy cattle strain in the person), it shows again that the US has to take dairy cattle infections more seriously. H5N1 in dairy cattle should be containable with short term but aggressive movement restrictions, testing and infection control measures – short term pain for long term gain. Fewer infected farms are being reported lately, which is great, but it’s still spreading across the country. The longer the outbreak lasts, the greater the chances of interspecies spillover and for the virus to adapt to a new host.
  • If the infection is somehow linked to wild birds, that’s a tougher situation, since controlling the virus in wildlife populations is challenge, to put it mildly.

This case was detected as part of surveillance program. That’s great, in that surveillance found something important and led to an action: an investigation of possible sources and a warning that there could be more. The not-so-great part is that few people with flu-like disease get tested at all, including for H5N1 influenza. If human-to-human spread is occurring, it could easily slip under the radar if there’s insufficient testing happening. That’s particularly true if most infected people only get mild disease, as they’re even less likely to get tested. We don’t know whether this was a lucky detection of a very rare situation, or a more common problem that’s been flying under the radar. Only more time and testing will tell us that.

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We started WormsAndGermsBlog on a bit of a whim. I didn’t really know much about blogs but Maureen Anderson and I we were working on a project to develop infectious and zoonotic disease resources for different audiences, and realized that making physical flyers (or CDs… remember those?) wouldn’t be overly impactful or sustainable. Around that time, I was at the Ontario Veterinary Medical Association conference and Dr. Doug Powell of barfblog (a food safety blog) fame was talking about their work.

So, I looked into and… WormsAndGermsBlog was born.

We had no idea what to expect, and not a lot of expectations, but it’s been good. Since the blog’s been fun, I figured we’d try something new to get information out, and hopefully have some more fun in the process.

So… WormsAndGermsPod was born.

We’re just starting out, so our catalogue’s pretty sparse, but hopefully the podcasts we have so far are useful (and maybe entertaining), and we’ll be adding to them.

Episode 1 is what I’m calling a “quick bite” – a short discussion about a topic I get asked about a lot: “Is methicillin-resistant Staphylococcus pseudintermedius (MRSP) zoonotic?“

Episode 2 is our first full-length podcast, and fittingly is with my partner in crime, Maureen, about one of her areas of expertise, rabies (particularly in Ontario).

You can find us on Spotify, Apple Podcasts, iHeartRadio, Amazon and other podcast services.

Suggestions for future topics are always welcome!

Warning: long post. TL;DR? We can drop the antiviral treatment duration for feline infectious peritonitis (FIP) to 42 days in many situations.

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In veterinary medicine, a lot of our recommended durations for treatment for different diseases have little scientific backing. We “inherited” a lot of these treatment regimens from the days when the drugs were first used, when we had to try something, and as we tend to be risk averse and err on what we assumed was the side of caution, the initial treatment durations were longer more often than not. Unfortunately, rarely are subsequent studies done to refine such treatment durations to see how short we can make them while still being effective. People (not just in veterinary medicine) are often hesitant to try shorter treatments because we are risk averse and don’t like to change. There’s often pushback against using treatments that are shorter than the “standard” duration, despite the fact that the standard duration was originally just a guess that seemed to work. Duration of treatment is a big issue that I deal with every day with antibiotic treatment, but it’s also an issue with the use of other drugs, including antivirals.

Antiviral treatment with GS-441524 (GS) and remdesivir for feline infectious peritonitis (FIP) has been truly game changing. It’s taken an almost invariably fatal disease and made it usually successfully treatable (as long as we don’t start treating too late). As of 2024, these drugs are now also legally accessible to veterinarians in North America.

The current “standard” treatment duration for FIP is 84 days (12 weeks). Why 12 weeks? Ultimately a duration had to be picked to start, and that’s the number that was chosen. We’ve stuck with it not because cats necessarily need 84 days of treatment, but because 84 days seems to work.

  • However, it would be better to shorten the treatment because the drugs are expensive, and treatment can be stressful on the cat (and sometimes the owner).
  • GS is a very safe drug, but remdesivir can cause nasty injection site reactions, so there’s a safety issue with longer treatment too.
  • Cost may be the biggest driver, as a lot of infected cats are in the care of rescues and shelters, which typically have very limited resources.

A recent study from Germany that we’ve been waiting to see in press (Zuzzi-Krebitz et al. 2024) has shown that we can likely reduce the duration of treatment to 42 days, at least in some cats. It was a randomized controlled trial (yay! we don’t get these done very often in veterinary medicine) that took cats diagnosed with FIP and randomly assigned them to get either 42 or 84 days of treatment with GS-441524 (15 mg/kg once a day). The cats were followed for 168 days to look at their response to treatment and to look for relapses. They enrolled 40 cats, which is a fairly small sample size, but not surprising since these studies are hard to do. There were 20 cats in each treatment group.

  • One cat in each treatment group died (one was on day 3 and one on day 31) so the duration of treatment had no impact on survival. (This also shows how game-changing this treatment is, resulting in a 95% survival rate for a devastating disease that when untreated can have an equally high fatality rate.)
  • All cats in both groups that survived to the end of their treatment course were in complete remission on day 168. That’s not a guarantee that none of them relapsed later, but 168 days is a pretty solid follow-up period.

The study used legally produced, compounded GS-441524 from BOVA in the UK. (That’s the same source used for importing these drugs to treat cats in Canada; BOVA has also partnered with Stokes in the US to provide access to the drug there too as of this summer). Using legitimate, pharmaceutical grade drug (versus black market or questionable compounding of research grade molecule) is another strong point of this study. It used a drug formulation in which we can have confidence in the quality and consistency, and that applies to what we’re using to treat cats here in Canada. BUT I would not extrapolate these results to treatment of cats with black market FIP drugs.

Does the drug dose matter?

I would also be a bit wary of extrapolating these results to cats treated with at the 10 mg/kg/day dose, which is a common treatment regimen for non-neurological and non-ocular FIP. Ideally we’d have data on duration of treatment for other dosing regimens too, but that’s probably not going to happen in the short term. That raises the question of whether we should move to the 15 mg/kg/day used in this study. How these results relate to the newer suggestion of using twice daily dosing is also unclear. I’d be more comfortable extrapolating this to 7.5 mg/kg twice daily (which is the same total daily dosage) than 10 mg/kg/day.

So, if someone is considering using a 42 day treatment instead of 84 days, I’d definitely use 15 mg/kg/day or 7.5 mg/kg twice daily.

Also note that this study focused on cats with effusive (wet) FIP.

There was one cat with neurological FIP and one with ocular FIP (one in each group) and they both survived. This could suggest that short durations are okay for these other forms of the infection, but I’d be really wary of making that call on a single case in the 42 day group. So, I would be hesitant to extrapolate these results to other forms of FIP. If there were compelling reasons to do so in a particular case, I’d be okay with a 42 day course in a cat with neurological or ocular FIP that responded really well to treatment. However, I’m a bit wary of saying we should move all of these severe cases to 42 days of treatment without more data and experience.

Finally, we need to remember that each patient is different. Response to treatment has to be part of the decision. If response is slow and incomplete at 42 days, that’s probably not a good stopping point.

As a small study, it certainly has some limitations, but this is a key study that gives us support to treat some (if not most) cats with FIP for a shorter time. That will be critical for situations in which cost is a barrier, both for shelters/rescues and homed cats. It’s one more step to making FIP a more easily treatable disease.

Thanks to the authors for doing the study.

Thanks to the cat owners for being willing to be part of the study, in which their cat might have been assigned to the group that received a shorter-than-typical treatment course.

  • That’s a big deal, because people can be reluctant to sign onto a study where they are worried about the effectiveness of one of the approaches.
  • If the study is looking at a new drug versus an old drug, there’s often optimism about the new drug, and people often hope to be be assigned to that group.
  • For studies about shorter treatment durations, there’s less motivation to be in the non-standard group, especially if the drug costs are covered either way, so there’s no cost benefit to the cat owner. However, cost can also be a motivator to participate in a study like this if the owner could not afford or didn’t want to pay for treatment of any duration.