Most of the time, when we talk about the parasite Dirofilaria in animals, we’re talking about Dirofilaria immitis….heartworm. However, it’s not the only member of the family that is found in dogs and cats. Another one, Dirofilaria repens, is present in those species in many regions, and it can also spread to people (via mosquitoes).
A recent report from Belarus, highlighted in ProMed-Mail describes 21 cases of dirofilariasis caused by D. repens. Interestingly, this is a relatively new finding for the area, as the disease was not reported until the mid to late 1990s.
This parasite naturally infects dogs, cats, and a variety of wild carnivores like wild canids (wolves, coyotes, foxes). Mature worms live in tissues under the skin of a suitable host and there, they produce larvae (microfilaria). These larvae enter the bloodstream and can then be taken up by mosquitoes. If a mosquito feeds on an infected animal and then a person, it’s possible for it to transfer the larvae into the person. People aren’t natural hosts, and the parasite almost never develops into its adult state. However, as the parasite undertakes its futile migration through a person’s tissues, trying to find a place to mature, the body mounts an immune response. This results in local inflammation, typically with development of little nodules. Very rarely, more serious infections can occur…. Surgical excision of the nodule, +/- antiparasitic drugs is the typical treatment.
Heartworm prevention practices should also prevent establishment of D. repens infections in dogs. Control of the parasite in the dog population would be an important control measure, but if the parasite is present at high levels in wild animals, that would complicate things. Basic mosquito control and avoidance measures also make sense.
A recent rabies death in a Russian man highlights multiple screw-ups that led to the man’s death.
A 50 year old man in Smolino Kovvrosko, Russia was bitten by his cat the end of February.
- Problem #1. The cat was presumably not vaccinated against rabies. Vaccination is not 100% protective but it’s pretty likely this was an unvaccinated animal. If the cat was vaccinated, the chance of it contracting rabies would have been very low.
The man went to the local ‘medical assistant’, but rabies prophylaxis was not given.
- Problem #2. Here was the opportunity to initiate the discussion about rabies. This would involve querying the health status of the animal and quarantining it for 10d to see if it developed signs of rabies (which would indicate the need for post-exposure treatment). Those weren't done.
A few days later, the cat started acting strangely. A local vet euthanized the cat. Rabies was not discussed.
- Problem #3. Malpractice. Plain and simple. A cat with neurological disease needs to be considered a rabies suspect. Bite history must be queried before euthanizing an animal. If rabies testing had been performed or if rabies had been mentioned as a possibility, the man might have been treated.
At multiple timepoints, there were chances to identify the potential for rabies, but multiple people screwed up and the man died as a result. Rabies is virtually 100% preventable with proper post-exposure treatment, but virtually 100% fatal by the time someone develops disease.
The location of this case can be seen at http://www.wormsandgermsmap.com
Clinical guidelines are fairly new (and limited) in veterinary medicine, although they’re widespread in human medicine. Following up on recent guidelines for diagnosis of treatment of urinary tract infections in dogs and cats, a working group from the International Society for Companion Animal Infectious Diseases (ISCAID) has completed guidelines for the treatment of a common type of skin infection in dogs, superficial folliculitis (pyoderma).
No, not what I write (although I certainly get enough emails suggesting otherwise... and I'm sure another round of interesting emails is going to be coming at my way shortly).
In the past, and even sometimes still today, public health has had to deal with the phenomenon of having "chickenpox parties." These are events held by well-intentioned but grossly-uninformed parents who deliberately expose their kids to a child with chickenpox in order to "get it over with." Yes, the children will get chickenpox and yes, the children will become nicely immune to the disease thereafter. Most of the time, it’s not really a problem, but then there are the times when a child develops serious (and potentially fatal) complications from chickenpox. Or when one child picks up chickenpox and spreads it to a high-risk child who then develops complications. It went so far at one time that at least one person was selling lollipops laced with chickenpox over the internet (until it was pointed out that this was essentially a bioterrorism activity).
We now have the analogue being recommended in dogs. The basic idea is to take young puppies to an area where distemper virus or parvovirus is likely present, so the puppy will be exposed and vaccination won’t be required.
Sure, it might work.
- The puppy might get exposed to enough virus to develop an immune response but not cause disease.
- Or the puppy might get sick and require expensive veterinary care.
- Or the puppy might get sick and die.
- Or the puppy might do any one of the three above and also spread the virus to other susceptible dogs, whose owners didn’t make the conscious - and dumb - choice to purposefully expose their dogs to these potentially fatal viruses.
Do vaccine reactions occur?
- Of course.
Are animals vaccinated more often than needed?
- Probably. Vaccination intervals are increasing so progress is being made. However, confusing the debate about how long we can go between vaccines with whether dogs should be vaccinated at all is dangerous. There's no doubt that young animals need proper early-life vaccination to prevent these potentially fatal infections.
Does the benefit outweigh the costs?
- Absolutely. Vaccination has controlled some incredibly important infectious diseases.
- Choosing not to vaccinate in response to internet rumours isn’t logical and it puts lots of animals at risk.
- Also, decreasing population vaccination rates increases the disease risk to the dog and cat population overall, since fewer protected animals means more chance of disease circulating from animal to animal to animal before it can be stopped. It’s like the “Wakefield effect”: the surge in some vaccine-preventable diseases attributed to the now-discredited (and former doctor) Andrew Wakefield, whose flawed and unethical research fed the anti-vaccine movement with since-retracted data.
Vaccination of young animals is critical for the control of certain infectious diseases. Recommending otherwise is illogical, and when it’s done by people who should know better, it’s unethical. Hopefully this doesn't get to the point where we need to start tracking the animal equivalent of the Jenny McCarthy Body Count.
A cluster of Brucella canis infections has raised concerns in Calgary, Alberta, and hopefully will prompt more discussion about importation of dogs.
Brucella canis is a bacterium that can infect both dogs and people, although it’s natural host is dogs (more specifically, dogs that are not neutered or spayed). Human infections are quite rare but they can be nasty, and therefore need to be taken seriously. Infections are sporadically identified in dogs in Canada, but it seems to be a very rare disease overall, and most cases I’ve dealt with have been in dogs that were imported.
The latest incident involves identification of brucellosis in five dogs. The first case, not surprisingly, was imported, having come from somewhere in the southern US. Three other dogs also from the southern US had contact with the first dog. The fifth case, concerningly, was a local Alberta dog that had contact with the first dog. There seems to have also recently been another unrelated Brucella canis infection in a local dog that originated from Mexico.
The main human health risk associated with Brucella canis is contact with breeding animals, as the bacterium is shed mainly in vaginal discharge, placental and fetal fluids, semen and aborted fetuses. Contact with dogs that have given birth or aborted is the main concern. The bacterium can be shed in urine, but that seems to be less of a concern, particularly with otherwise healthy dogs. The risk to the general public is therefore quite low, but it’s important to try to control this bacterium because of the potential for serious human disease.
Brucellosis is just one of many potential disease risks with imported dogs. As I’ve discussed previously, there is little to no control over importation of dogs and little comprehensive guidance for people who are importing them. This is a big reason why we are seeing certain "foreign" diseases in dogs in Canada (e.g. leishmaniasis). We sorely need a comprehensive approach to dog importation to help reduce the risk of disease entry and help people who choose to import dogs do so safely.
This cluster of infections can also be found on our new disease tracking site, http://www.wormsandgermsmap.com.
A few questions were sent in by a reader regarding a recent post about rabies in a Texas animal shelter. They’re good ones so I thought I’d cover them here.
I'm a little confused by this. Weren't these shelter dogs vaccinated?
- Probably not. Many shelters don’t vaccinate against rabies. There are a few reasons for this:
- One reason is cost. From a shelter standpoint, rabies vaccination may even be considered of less importance compared to vaccination against diseases that are more common causes of illness in shelters (such as parvo).
- A big reason is that in most regions, rabies vaccines must be given by a veterinarian, and many shelters don’t have much veterinary involvement.
- Another consideration is that even if animals are vaccinated in the shelter, they are not considered protected until 28 days after vaccination.
- Yet another thing to consider is whether vaccination would have changed anything. Vaccinated dogs would still require a 45 day observation period. That’s much easier than a 6 month quarantine but still problematic and could lead to euthanasia for logistical reasons.
How exactly were these dogs exposed?
- Good question. It depends how the shelter was run and whether dogs were mixed together or socialized in groups. Sometimes, all dogs end up being considered exposed unless shelter personnel can definitively state that they know a particular dog didn’t have contact with the rabid dog. It’s often hard to say that with confidence, so by default they consider all dogs exposed.
What about vaccinated pets (dog and cat) that live in homes but go outside in suburban or rural environments? How do we know, for instance, that an indoor/outdoor cat hasn't come into contact with a rabid wild animal or feral cat? Do owners of indoor/outdoor cats really know where their cats go and what they do or who they associate with when they're out all day long? And, what about dogs that go out for their last potty break, unattended, in the fenced backyard at night when the wild critters come out? How do we know, really, that our pets haven't been exposed to rabies?
- We don’t. That’s an inherent risk in life, and a reason that we push for vaccination of all pets. Vaccination isn’t 100% but it will greatly reduce the risk of an animal developing rabies.
- This is also one of many reasons to make sure animals aren’t allowed to wander outside unsupervised.
A single rabid animal has lead to plans to euthanize 40 dogs at a Texas animal shelter. It’s very similar to a situation I discussed with vet students recently, and it’s one that raises a lot of emotions.
The brief version...one rabid dog was identified in the shelter.
- This means that consideration has to be given to who (people and animals) was exposed to the dog.
- If the shelter cannot state with confidence that a particular dog was not exposed to the affected dog (e.g. if they don’t strictly cohort groups and/or follow these practices), then it’s considered exposed. Fortunately, only 40 of the over 300 animals at this shelter were deemed potentially exposed. It’s not clear if this is because some dogs were considered unexposed or, more likely, that all dogs were considered exposed but cats were kept separately and therefore not exposed.
- A dog that’s been exposed to rabies needs a 45 day observation period (if properly vaccinated) or 6 month quarantine (if not known to be properly vaccinated) or euthanasia.
What are the odds that any other dogs were actually infected? Very low.
Is euthanasia, then, a reasonable response? Unfortunately, yes, in many situations.
This is where people start to get upset. Why euthanize these perfectly healthy dogs if none were likely going to get rabies and you can simply quarantine them?
At a basic level, I agree. But, when you think about it more, these actions make sense.
- Yes, the dogs could be quarantined, but how? That would involve keeping them in the shelter for 6 months, since fostering out rabies-exposed dogs would be hard to justify.
- If they quarantine them in the shelter, they essentially have to keep the shelter closed since it would make no sense to bring in more dogs (that would have to be strictly isolated from the others) and there’s probably little or no room for added dogs anyway.
- As a result, instead of being admitted to the shelter, the animals might be euthanized on the doorstep, since there’s often not a "plan B" for sheltering.
So, does it make sense to shut down the shelter for quarantine? That’s hard to justify. The net impact on dogs (both those in the shelter and those that would be admitted) plus considerations of shelter operations (e.g. lots of presumably unvaccinated people having to work with potentially exposed animals) need to be part of the discussion.
Unfortunate as it is, this is often the response. Ideally, there’d be a way to isolate these dogs and continue shelter operations (and pay for the extra costs associated with doing this). In the real world, this is rarely an option.
All of this could potentially have been prevented if the affected dog had been properly vaccinated by its original owners.
There have been a few reports of equine herpesvirus (EHV-1) neurological disease over the last couple of weeks and some other cases that have been less well publicized. Hopefully it’s all just been a blip on the radar and not a sign of things to come as equine events start to ramp up at this time of year. However, it would be good for racetracks to take these cases as reminders of the ever-present risk of EHV and the need to try to prevent problems.
Some tracks have taken this issue seriously and are working on infection control and outbreak response plans. In response to one outbreak, a Minnesota track is building an isolation area for infected horses and implementing a variety of infection control measures.
Too often, the response to EHV-1 is only reactive: when there's no immediate problem, people don’t do anything, and when there is a problem, people freak out (and it’s hard to do things right when people are freaking out).
We need a happy middle ground that includes a reasonable response plan (effective and realistic) and proactive measures to both reduce the risk of an outbreak and to facilitate response.
Racetracks are starting to understand the need, although the response is variable. The number of outbreaks and the potential implications of them (e.g. sick or dead horses, cancelled racing, horses banned from going to certain tracks) means that it is in the horse owners’ and tracks’ best interests to do things right. What constitutes "right" is a moving target, though, and some people just don’t want to bother.
You can virtually guarantee that there will be EHV-1 outbreaks at racetracks this summer. A limited number of horses will die but there will be massive disruption based on quarantines (sometimes reasonable, often excessive) and other fall-out.
While there’s no way to completely eliminate the risk of EHV in horses, there are many things that can be done to reduce the risk of an outbreak. Some are relatively cheap and easy, such as
- Ensuring that horses with signs consistent with EHV-1 are promptly examined and isolated
- Avoiding shipping horses from sales directly into racing barns
- Cohorting groups on tracks as much as possible to contain incidents to individual barns
- Fostering routine infection control practices by people who frequently move between barns like veterinarians, farriers and riders/drivers
Other measures may take more time, effort and planning, such as creation of isolation areas and development of clear outbreak response plans. One of the most important things that can be done, however, is improving communication and trust. Often the biggest challenges in outbreaks involve poor communications, such as unwillingness to report cases, egos and agendas that get in the way of effective and timely response, and various other related problems that can be fixed by people thinking and talking to each other.
Some tracks are doing a good job of thinking proactively. Many are taking the "head-in-the-sand" approach. Any track could run into a problem, but my money’s on bigger problems occurring at the tracks that don’t take this problem seriously.
Unfortunately, we’ll be talking more about EHV-1 outbreaks this summer.
“Seek and you shall find.”
That might be the simple explanation for why we’re hearing more about spillover of different types of flu viruses into dogs. Sporadic reports of dogs being infected by different flu viruses keep coming in these days, maybe we didn't get this reports in the past because people just often didn’t bother testing dogs when doing surveillance of flu outbreaks in other species.
The latest incident is a report of finding antibodies against the H5N8 avian flu virus in a dog on a South Korean farm. This H5N8 strain is different from the H3N8 canine flu strain that has become a true "dog-flu", having adapted to dogs following spillover from horses.
This potentially emerging H5N8 avian flu virus has caused a lot of concern in southeast Asia as it can be devastating to poultry farms. It doesn’t sound like the dog in this case was sick, but the suspicion is that the dog was infected by eating infected poultry.
Avian flu viruses are a concern because some avian flu types can infect people and cause very serious disease. They can also cause devastating outbreaks in birds. Mixing of avian (and other) flu viruses with human viruses is the biggest concern, as it could potentially create a new pandemic virus that retains its high mortality in people but spreads much more easily like regular human flu strains. Adding more species to the mix adds more potential routes for transmission and flu virus recombination. It's likely that dogs are of little to no concern here, and the dog was probably never infectious - it just got exposed, mounted an immune response and the virus died. However, it indicates the need to consider broader surveillance, involving various companion animal species, when investigation new influenza threats.
Actually, the title of this post should be “Obese cat attacks family after being booted in the rear as a disciplinary measure. Family freaks out but wants to keep cat.”
Oh, where to start.
1) A 22 lb cat is obese and there are obviously animal care issues.
2) Kicking a cat in the rear after it objects to having its tail yanked by a baby is hardly an appropriate training measure
3) A cat that will attack with enough vehemence to make a group of adults barricade themselves and call 911 has other behaviour issues.
4) A family that thinks a cat that has a history of aggression and that made them barricade themselves in a room and call 911 is still an appropriate family pet for a household with a seven-month-old child is delusional.
While there may well be more to this story than has been reported, it seems like the baby pulled the cat’s tail, the cat objected and scratched the child, the owner kicked the cat, the cat responded, and the owners ended up locking themselves in a bedroom and calling 911 saying "I kicked the cat in the rear, and it has gone over the edge, He's trying to attack us -- he's very hostile. He's at our door; he's charging us" as the cat screeched in the background.
Yet, after all that they apparently want to keep the cat, though they "definitely want to keep [the cat] away from the baby and keep an eye on his behavior."
Does this cat pose a major risk?
It’s hard to say. Probably not in most circumstances, but it can certainly be sent over the edge and respond very aggressively, something that has apparently happened more than once.
Should this cat be in this household?
Probably not. It’s in a household with a high-risk individual (the baby). Kids sometimes inappropriately handle animals, and this cat clearly doesn’t respond well to provocation. The owners don’t seem equipped to handle this properly. The cat might be perfectly fine in a household where it’s not provoked, but it doesn’t seem like a good fit for this household.
Can anything be done to prevent further problems?
A few things need to be considered. The first is a veterinary exam to make sure there’s not a physical reason for the cat’s response (e.g. is there a problem that made a little tail pull cause severe pain?). A consultation with a veterinary behaviourist (a veterinarian that specializes in behaviour as a result of extensive specialty training - not a self-proclaimed, untrained "pet psychologist" that the owners mentioned) would then be indicated to try to identify why this happened, and how (or whether) it can be prevented in the future.
While rarely (if ever) is there a situation where there should be no pets in households, there are situations where a combination of a certain pet and certain people doesn't fit. This is probably one of those.