Worms & Germs Blog

Are Dogs Good Sentinels for Human Lyme Disease Risk

Posted in Dogs, Other diseases

My lab has been spending a lot of time on Lyme disease over the past couple years. It’s a fascinating (and frustrating) disease to work on, and we need to learn a lot more about it. In this region, we’re seeing clear changes in ticks and the diseases they carry. With climate change, that’s not going to get any better. It may be -14C outside at the moment, but we have more tick-friendly weather over the course of the year than we’ve ever had.

One interesting aspect of Lyme disease surveillance is the abundant canine data we have. It dwarfs human data, in large part because annual heartworm testing is often done with a test that also detects antibodies against Borrelia burgdorferi (the cause of Lyme disease), Ehrlichia and Anaplasma. So, we get a lot of ancillary data, even if the animals weren’t tested because of a suspicion of disease. We’re currently working on a huge Canadian dataset, and one of the questions that comes up is “what is the relevance of canine data to humans?“. There’s some info from the US that suggests that canine exposure to Borrelia can indicate the risk of human exposure, something that makes sense, since dogs and people are exposed the same way….being bitten by an infected Ixodes scapularis tick.

Public Health Ontario has just released a systematic review evaluating companion animals and tickborne diseases. The results aren’t astounding but it’s a comprehensive review of the subject.

Here’s the summary:

Our systematic review indicates:

1. Dogs provide suitable spatial seroprevalence data for assessing the risks of tick-borne disease in humans.
2. Companion animal ownership does not appear to pose additional Lyme disease risk to owners.

Data collected from the testing of companion animals within the veterinary health system can help establish the distribution of B. burgdorferi while identifying new areas and the direction of pathogen movement. In addition, data collected from companion animals are valuable in estimating the prevalence of a pathogen over time and can help test hypotheses of pathogen ecology and epidemiology or test the efficacy of prevention efforts.

The best way to understand the shared risks of tick-borne pathogens to humans and companion animals is to ensure ongoing information sharing between veterinary, medical and public health professionals. Continual information sharing increases overall awareness, which leads to collaborative research of tick- borne pathogens in humans and companion animals. Included within these shared efforts is assessing the distribution of pathogens in humans and animals and tick vectors, leading to improved risk assessments and prevention of disease in Ontarians and their companion animals. PHO will continue to work with partners on ways to improve tick-borne disease surveillance.

Fossil fuels and antibiotics: An analogy

Posted in Animals, Birds, Cats, Dogs, Horses, Other animals, Other diseases, Pocket pets

The post below is reproduced from CANresist.blog. It applies equally for veterinary medicine.

I think most people buy into the concept of fossil fuels being finite resources. Someday, they’ll run out or logistics and cost of extraction will make them impractical. Accordingly, we’re thinking about ways to reduce and improve use (to delay the end of the fossil fuel era) and develop effective alternatives. People know all about this, but motivation is somewhat limited by the fact that we’re not going to run out of oil in our lifetimes.

There are some good comparisons to antibiotics. Unlike other drugs, we have to consider them to be finite resources. There’s always some degree of “use them and lose them” because of antibiotic resistance. Like oil, we need to reduce and improve use to delay the end of the antibiotic era, and come up with alternatives. However, unlike oil, the time frame is potentially much shorter. Antibiotic resistance isn’t a threat for future generations. It’s a threat for every one of us.

Modern medicine needs antibiotics. The 50th anniversary of Dr. Christiaan Barnard’s first successful human heart transplant was a little over a week ago. Without effective antibiotics, transplants (and many other routine procedures) would be a thing of the past.

Putting things in that perspective should motivate us to put the required time, effort and money into antimicrobial stewardship. It’s not as flashy as a new Tesla, but it’s more important.

What’s up with canine leptospirosis

Posted in Dogs, Other diseases

http://oahn.ca/wp-content/uploads/2016/07/OAHN-Infographic-Lepto-Mgmt-Final-20160704-page-001.jpgAs I’ve mentioned in a previous post, this seems to have been a bad year for leptospirosis in dogs in various areas. In at least a few location in Ontario, we are seeing a very high rate of disease, well beyond what we’ve seen before. I was giving some talks in Buffalo the other day and some people there reported a similar problem. Outbreaks have been identified in other diverse places in North America, including Nova Scotia and Arizona.

Why?

It’s always hard to say, and some aspects of this vexing bacterial disease make it a challenge to investigate.

Whenever we’re looking at an apparent increase in disease incidence, a few potential contributing factors come to mind:

More awareness and reporting

  • This can certainly play a role, but I think it’s abundantly clear that there was a true increase in lepto cases this year, at least around here.

New or better tests

  • New tests have become available and our ability to diagnose leptospirosis has improved, but not recently, so this also can’t account for the dramatic increase in cases.

Changes in the reservoirs and sources of the bacterium

  • Leptospira can be carried by various types of wildlife, with rats and raccoons probably posing the biggest risk in this part of Ontario. Changes in the numbers, distribution and lifestyles of reservoir hosts can result in changes in exposure of dogs (and people). Booming populations of these wildlife hosts, movement of them into new areas and other things that increase direct and indirect contact (especially contact with urine from infected animals) could result in increased disease risk.

Changes in Leptospira serovars

  • There are many serovars (types) of Leptospira, and these can have different disease risks, hosts and infectivity. We don’t have a great handle on what’s going on in this respect, and it’s an area I’d love to study more.

Vaccine breakthrough

  • Changes in serovars that are included in vaccines or increases in strains not covered by vaccines could also result in more disease. However, in my experience, lepto is very uncommon in vaccinated dogs. I’m not sure I know of any vaccinated dogs that developed disease in the recent/ongoing situation. So, that’s probably not playing a significant role.

Clearly, we need to figure out more about what’s going on. Hopefully lepto season is at an end here (with cold weather and tonight’s forecast of a blast of snow will help). That’s not necessarily true in warmer areas, and a big question is whether this fall has been an outlier or whether it’s the “new normal.” Only time will tell.

  • From the pet owner’s perspective – because contact with urine from ubiquitous wildlife is almost impossible to preclude if your dog goes outside at all – the biggest thing that can be done is vaccination. It’s safe and effective, and while no vaccine provides a 100% guarantee, it’s a worthwhile investment to protect from a very nasty disease that can be very expensive to treat.
  • For veterinarians, it’s awareness about the disease so that cases can be promptly identified, with treatment provided as early as possible. It’s also important to be aware of potential lepto cases so that proper infection control practices can be used to reduce the risk of zoonotic infection.  The Ontario Animal Health Network (OAHN) has produced a handy infographic for managing lepto patients in-hospital.

More information about leptospirosis can be found on the Worms & Germs Resources – Pets page.

Please avoid DIY head removal for rabies testing

Posted in Dogs, Rabies

A dog attacks someone and is shot by police.

  • Unfortunate, but sadly it happens.

The sheriff’s investigator notifies the county health department, which says the dog needs to be tested for rabies.

  • Good. That sometimes gets missed.

The investigator then tells the owner that he has to remove the dog’s head or he’ll face a charge of disorderly conduct.

  • Uh… pardon?

That’s apparently what happened to a man in Crawford County Georgia, much to the chagrin of public health officials (and most people with common sense). As is often the case, the story’s a bit murky but the owner ended up removing the head under threat of arrest if he didn’t.

Not surprisingly, the rabies test was negative. Yet, it doesn’t excuse the strange and potentially dangerous situation. Removal of the head has to be done safely (something that requires some knowledge, training and equipment) and for testing to be possible, it has to be done properly so that enough intact brain is submitted to the laboratory.

It also shouldn’t get lost in the mail… but that’s another story.

Did anyone get a dog brain they weren’t expecting?

Posted in Dogs, Rabies

If a dog bites a person or another animal, there are two ways to make sure that the bite couldn’t have resulted in transmission of rabies virus:

  • Euthanize the dog and test the brain for rabies.
  • Ensure the dog is still neurologically normal 10 days later (if this is the case, then the dog could not have been shedding rabies virus at the time of the bite).

In some scenarios people may be quicker to use option #1, for example if the plan is to ultimately euthanize the dog regardless. If the dog is seriously ill and/or it’s not humane to keep the dog alive for 10 days then this makes sense.  Euthanasia is often elected for particularly aggressive dogs as well, since it eliminates the risk of more bites during the 10 day observation period. However, it’s important to consider that if there’s a problem with the sample or the test, then one always needs to err on the side of caution and assume it was rabid, unless there is a definitive negative test result.  It’s pretty unlikely to happen, but you never know.

A recent case highlighted why that consideration is valid.

Personnel from an East Texas vet clinic euthanized a dog that was showing potential signs of rabies. It had bitten a veterinary technician during an examination and the owners elected to euthanize the dog because of its poor health.  That’s all reasonable, and they obviously needed to test the dog for rabies under the circumstances. The head was removed and sent via courier to the diagnostic lab.

Then… well, your guess seems to be as good as UPS’s as to where the head is now.

As a result, the technician and other people who handed the dog will need rabies post-exposure prophylaxis (PEP), which is far from convenient or cheap (the article quotes a cost of $80,000 to treat all the exposed staff). Even if they find the package, if it takes more than a couple of days it’s unlikely that the head will be in an acceptable state for testing (especially when you consider the likely ambient temperature in warehouse or shipping truck in Texas).

In a case like this, euthanasia was the right response and this is just a very bad-luck outcome. It’s a reminder, though, of what can happen, and why I like to see observation done before euthanasia if there’s not a pressing need to euthanize the biting animal immediately.

I have to wonder, though, what happened to the head? It didn’t just vanish. Will it turn up eventually (useless for testing and very stinky)? Where do packages disappear to? Hopefully someone else didn’t get it by mistake – not a nice package to open if you’re not expecting it.

Leptospirosis from Puerto Rico hurricane dogs

Posted in Dogs

When Puerto Rico was devastated this fall by Hurricane Maria, I got a few calls from groups thinking about rescuing dogs from the island, and wanting to know what infectious diseases I’d be concerned about. Leptospirosis, a potentially serious bacterial infection that can be transmitted from dogs to people (although that’s fortunately uncommon), was at the top of my list. Unfortunately, that’s turned out to be exactly the case, as several puppies brought north from Puerto Rico by a Vermont rescue developed leptospirosis after arrival.

Importation always carries some inherent disease risks. That’s why we (should) use some common sense practices to reduce the risk. This may include careful selection of animals, pre-screening for certain diseases before exportation, testing on arrival, and infection control practices during for a period after arrival.  These measures are still no guarantee, but they should reduce the risk of the new arrivals carrying, developing or spreading infectious diseases.

There was one additional noteworthy detail from a news article about the puppies in Vermont:

A couple of days later, the puppies were taken to the outdoor patio at Ramunto’s Brick and Brew Pizzeria so that the patrons and customers could interact with them.

  • Not a great idea. Adopted animals need time to adapt to their new environment. They also should be quarantined for a while to see if they have any problems and to reduce the risk of them transmitting anything to other animals or people. Here, their caretakers (well intentioned as they may have been) created more risk by taking newly imported puppies out in public rather than isolating them for a period longer than a couple of days.

More information about leptospirosis is available on the Worms & Germs Resources – Pets page.

Dog bites, irony and injured kids

Posted in Dogs

If it wasn’t for the injured child, this would be a funny story.

There was a hearing in Hillsborough County, Florida about a proposed ordinance requiring dog trainers to be licensed. Not surprisingly, that didn’t go over well with all trainers. One of the main opponents was waiting in line to get into the hearing, and (you can guess where this is going) the dog he brought with him lunged at a 5-year-old boy and bit him in the face. The article was sent to me by a reader in response to a recent fake service dog post, and yes (you can guess where this is going again) the dog was wearing a service dog vest. So, a badly behaved dog wearing a presumably fake service dog vest, and owned by a “trainer”, attacked a child during a hearing where the dog’s owner was protesting scrutiny of dog trainers.

So, now we have a child with bite wounds and a dead dog (it was euthanized shortly after the bite), all because someone who thinks he/she is a dog trainer who doesn’t need any regulation or oversight didn’t know how to train or handle a dog.

Reality is often more bizarre than fiction.

For a better story about service dogs, click here to see a video of a dog being trained by America’s VetDogs, a group providing therapy dogs to US military veterans, dropping the puck at a NY Islanders game.  There are people and organizations that do an excellent job training service and therapy dogs.  The challenge is being able to separate the good from the bad, and preventing the latter from causing problems for the former.

Influenza from a cat (and no we’re not all going to die)

Posted in Cats

A paper in December’s Emerging Infectious Diseases (Marinova-Petkova et al. 2016) follows up on last year’s outbreak of avian influenza (H7N2) in cats in a New York shelter and one associated human infection (the findings were also summarized in a post from earlier this year). This paper describes investigation of the virus from the infected person and from a cat at the shelter.

The take home message is that the virus from the person and the cat were almost identical, meaning it’s pretty certain that the person was infected by an animal at the shelter. The study also showed that the virus was very similar to a low pathogenicity avian flu strain that was circulating in the US in the early 2000s.

Presumably, this strain is still circulating in birds, and it happened to spill over into a cat (outdoor cats that hunt are at risk of exposure). Then, an infected cat (during the short period it was infectious) happened to enter the shelter, have contact with other cats (again, during that short period when it’s infectious), with transmission to more cats and ultimately a person working with them.

It’s an interesting scenario, for sure. However, it’s not overly concerning.

  • We know various flu viruses can periodically infect cats.
  • This outbreak burned itself out pretty quickly.
  • There was just one known human infection, and it was in someone with close contact with the cats.
  • The fact that a cat could get infected, go into a shelter and have contact with other cats in the shelter during what is likely a window of just a few days when it’s infectious is pretty unlikely. Often, strange disease events are “perfect storm” manifestations like this. The odds of any given cat carrying influenza virus at any time are exceptionally low.

This is a good reminder of the potential for inter-species transmission of influenza virus and the potential for pets to act as disease bridges between wildlife and humans. However, it’s important to keep things in context and realize this is an oddball scenario, not a sign of a new serious problem

Airport dog bite

Posted in Dogs, Rabies

While waiting in line to check-in for a flight in Orlando, a JetBlue passenger was bitten by a dog. This raises lots of issues and questions, and for the bitten individual, she’s dealing with a pretty nasty bite and also the potential need for rabies post-exposure prophylaxis.

  • She was bitten while checking in, so it was a public area. Who knows why the dog was there, since JetBlue says the owner is unknown and wasn’t a passenger on one of their flights (not sure how they can say that with much confidence). A bite-prone dog in a busy place like an airport is a recipe for disaster. On a plane would be worse, and I have to wonder if this was a typical “fake” service dog.  I’ve ranted about this before, but the proliferation of these animals is astounding. It’s so common, especially in the US, to see dogs wearing vests identifying them as service dogs, and I recognize a few of those from companies that sell them online as a way for people to bring their pet dogs everywhere. (It’s sad to say, but a general rule for me is that if a dog wearing a “service dog” vest, it’s probably a fake).

The response to the bite raises other issues. No one has been able to identify the dog’s owner.  JetBlue has offered to cover her medical bills and gave her a travel voucher, but has said there’s nothing they can do to identify the person, who promptly left the terminal. Any bite from a dog has to be considered a potential rabies exposure, even though the risk in the US is exceptionally low. However, since rabies is almost invariably fatal, “exceptionally low” is still usually too high. So, if it cannot be proven that the dog is healthy 10 days after the bite, and therefore couldn’t have been shedding rabies virus at the time, a series of post-exposure shots will be indicated.

The article about the bite incident states: Langlois has been on a course of pain meds and antibiotics for the last week, but the real pain may still be ahead if she’s forced to undergo a series of rabies shots, something even her doctor is hesitant to do. “He’s like ‘it’s an extremely painful shot and it’s a series of three, I wouldn’t want you to go through that that if you didn’t have to.”

  • That’s pretty overblown, and scaring people about rabies treatment isn’t good. It’s just a series of vaccines, plus a shot of antibodies (given just like a vaccine). Yes, it hurts a bit but for most people it’s not a big deal. (Yes, I can say this from experience). There are many things I’d rather do than get a rabies shot, but it’s a minor inconvenience.

Most likely, the dog will not be found unless JetBlue and the airport decide to put the time and energy into looking. There’s almost certainly video and a picture of that (or a warning that if the person doesn’t come forward, they’ll have to broadcast the picture to help find him or her) would potentially help track the person down. It doesn’t sound like that’s going to happen, so most likely, the woman will have to get post-exposure prophylaxis and she’ll be fine.

Hopefully that dog stays away from airports now.

Antibiotic Awareness Week commentary

Posted in Uncategorized

Imagine a world without antibiotics: deaths and complications from simple wound infections, routine surgical procedures would become high-risk, immunosuppressive therapy such as those used for cancer treatment would be as life-threatening as the disease itself.  Such was life in the pre-antibiotic era, and we could be facing the same situation in the post-antibiotic era if we’re not more careful.

It’s Antibiotic Awareness WeekClick here for the complete commentary from Clinician’s Brief.