Worms & Germs Blog

Worms & Germs Blog

Promoting Safe Pet Ownership

Rabies in developing countries

By Scott Weese on Posted in Dogs, Rabies, Vaccination

We often talk about rabies in the context of high GDP countries, focusing on wildlife rabies and exposure during travel. However, in many parts of the world, exposure to canine rabies is an ever-present risk, and there can be substantial barriers to getting proper post-exposure prophylaxis (PEP) when needed. That’s part of the reason tens of thousands of people still die every year from canine rabies.

A recent paper in Clinical Case Reports (Audu et al. 2019) describes two cases of human rabies in Nigeria that highlight some of these challenges:

  • The first person was a 40-year-old man who was bitten by a stray dog. The dog was killed by people in the community but not tested for rabies. He went to a local health clinic where he got a tetanus shot and antibiotics, but no rabies PEP because they didn’t have any. He was referred to another facility about 100 km away, but chose not to go. Rather, he tried a traditional treatment that involved eating the liver of the biting dog and putting hairs from the neck of the dog on the bite wounds. Two months later, he developed signs consistent with rabies and died.
  • The second person owned a puppy that developed rabies. The puppy had bitten her and two neighbours and was confirmed as rabid after it died. Neither the puppy nor its dam had been vaccinated. The neighbours received PEP but the owner declined because of the cost. Five weeks later, she developed signs consistent with rabies and died.

These represent just two of the thousands of people who died of rabies in 2017, but their stories are not unique.

Getting people to go to a doctor after a dog bite is the first challenge, and education of the public is needed to make that happen. However, it doesn’t help if there is then no access to rabies PEP. Traditional treatments are sometimes used because there’s no alternative, but they are also sometimes used instead of available and highly effective conventional treatments. Vaccination of dogs is a useful rabies control tool but has limitations in areas where canine rabies is endemic and where feral dog populations are large. The target is vaccination of 70% of dogs, and groups such as Mission Rabies have done a lot to help hit that target. However, rabies will continue to circulate in many regions. Vaccinating pets, the animals that have the closest contact with people, is important but is not often done in some areas because of cost, failure to recognize the need and lack of access to vaccines.

Costs of seeking healthcare and rabies PEP can be a substantial barrier. In case 2, the cost was ~$68 USD (much less than the exorbitant $48000 that was recently charged to one woman in the US for rabies PEP), but even that was unaffordable to the victim.

The solution to the rabies epidemic isn’t straightforward. Education of the public, veterinarians and healthcare providers, improved healthcare access, reduced cost of treatment and more widespread vaccination of dogs are important but can be challenging. There’s no simple solution to the problem, but economic development (facilitating education, healthcare, transportation and drug access) is a big component. Barring that, education and vaccination efforts are critical.

New infographics: Echinococcus multilocularis, feline upper respiratory tract infection

By Scott Weese on Posted in Cats, Dogs, Other diseases, Parasites

The title says it all… see below for the latest and greatest infographics from the Ontario Animal Health Network, including an update to the very popular E. multilocularis infographic and a new one on treatment of feline upper respiratory tract infection.

 

To download the infographics in pdf format, visit oahn.ca at these links:

Treatment of feline upper respiratory tract infection

Emerging risk: Echinococcus multilocularis in Ontario

 

Brucella canis in imported dogs: Ontario

By Scott Weese on Posted in Dogs

I’ve been holding off on this post because the situation is still evolving, but there’s enough of a rumour mill developing (and I’m getting enough emails from concerned people) that I thought I should respond.

A little background:

  • Brucella canis is a bacterium that can cause a variety of issues in dogs (particularly reproductive issues), and can also be transmitted to people.
  • While it’s rare (well under 1%) in pet dogs in Canada and the US, it’s more common in dogs from commercial breeding operations (e.g. puppy mills) and dogs from certain parts of the world.
  • We don’t see infections in dogs here very often.  When we do, most of the time (but not always), it’s a dog that came from somewhere else.
  • B. canis is hard to treat and it’s hard to have confidence that it’s been eliminated from the dog after treatment, even if visible signs of illness have resolved.
  • It can also be spread to people. However, human infections seem to be rare and close, direct contact is likely required for transmission.
  • The greatest human risk likely comes from contact with female dogs that have aborted or recently given birth (whelped), since the bacterium can be present in high numbers in fetal and reproductive fluids and tissues.

Current situation in Ontario:

It’s my fault, I guess, since we’ve started screening imported dogs for disease surveillance as part of a research project. If you don’t look, you don’t know. If you do look, sometimes you end up revealing a complicated situation.

It wouldn’t really be surprising to find B. canis in a small percentage of imported dogs, since foreign, intact (i.e. not neutered or spayed) dogs are a higher risk group for infection to start. So, it isn’t a shock that we have identified some suspected and presumptive cases in recently imported dogs. Diagnosis of B. canis infection isn’t always straightforward either, so it’s tough to be definitive at this stage.

Testing of healthy dogs involves use of a screening test (RSAT) to start. This type of test has a high sensitivity (it will pick up a very high percentage of infected dogs) but a lower specificity (some dogs that aren’t actually infected will test positive too, these are known as “false positives”). Dogs that are positive on the screening test are then tested again using other tests to try to confirm the diagnosis. So far we have one dog that was positive on the second test. We have some others that were positive only on the first screening test. That could be because there was a cross-reaction and they are actually false positives, or it could because they were only very recently infected, or because the follow up tests aren’t as sensitive. With that type of result, we consider them suspicious and typically recommend trying other tests or repeating the testing in a month or so.

Take home messages (at this point):

  • 1 dog with B. canis infection is a concern but it’s not overly surprising. A lot of infected dogs would be more of a problem. We’re trying to sort out which scenario this is.
  • With infectious diseases, it’s best to err on the side of being overly cautious at the start and take extra precautions initially, while things are being sorted out. Sometimes we look back and realize we didn’t need to do all those things based on the final result, but it’s better than not doing enough at the start and then trying to play catch-up later.
  • The risk to the general dog population is very low. Close and direct contact with an infected dog is required for transmission to either other dogs or people.
  • The current situation is likely lower risk than many other situations, such as people buying dogs that came from puppy mills or other imported dogs where no one is looking at their disease status at all.
  • The groups with which we are working are taking a proactive approach to make sure problems don’t develop or spread.
  • Knowing is better than not knowing, even if it sometimes causes confusion or concern at first.

More information will follow, and if there’s a significant risk to the broader dog or human population, I’m not one to hold back saying that. At this point, people shouldn’t worry.  For more information on B. canis in dogs and the associated public health risks, a review of the topic was recently published in Emerging Infectious Diseases.

Revised ISCAID guidelines for diagnosis and treatment of urinary tract infections in dogs and cats

By Scott Weese on Posted in Cats, Dogs

Hot off the press… the newest edition of the International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats has been published in The Veterinary Journal. These are updated and expanded clinical guidelines that have been in the works for the past couple of years, as a followup to the initial 2011 guidelines. They are meant to be open access (i.e. free to download), but there have been issues for some readers who were unable to download them to date – we’re looking into it.

New imported distemper strain in dogs

By Scott Weese on Posted in Dogs, Other diseases, Vaccination

Here’s a report from Cornell University’s Animal Health Diagnostic Center, describing importation of a canine distemper strain that hasn’t been found before in North America:

02/05/2019: (N. America) In early October of 2018, a 12-week old “Sheltie” arrived from Korea. Approximately 12 days later, the dog began with a cough and lethargy with blood work indicating “anemia”. About 10 days later, the dog developed a unilateral myoclonus with relapsing lethargy. In another week the neurological signs had progressed to tonic clonic seizures that continued to worsen to a persistent uncontrolled myoclonus at which time the dog was euthanized.

Samples (serum, ocular swab, urine) obtained at 9 days post onset of clinical signs were forwarded to the AHDC for canine influenza virus serology and canine distemper virus RT-PCR testing. The HI serology test indicated no exposure to H3N2 CIV which is the endemic strain of flu A in Korea. However, the RT-PCR tests on the ocular swab and urine were strong positive for canine distemper virus. Attempts were made to isolate the virus from the samples submitted for PCR, but with no success. Our next effort was to try to obtain sequence for virus directly from the nucleic acid used for the RT-PCR assay. This was successful for the F and H genes of CDV. Phylogenetic analyses of the sequences against various clades of CDV, indicated the imported dog was infected with the Asia-1 strain of CDV. We have no information on the existence of this clade of CDV in North America.

While we have been most concerned with the importation of canine influenza virus from Asia to North America by improper procedures by various “rescue” groups, the importation of CDV may be more significant in that CDV once it enters an ecosystem cannot be eradicated even with effective vaccines. Once again the North American dog population is being put at risk by those who have no regard for the importation of foreign animal diseases.

Drunk raccoons?

By Scott Weese on Posted in Rabies

Rabies and distemper are the two things that come to mind first when a raccoon is acting strangely. Rabies is a big concern because it can also be transmitted to people. Distemper is also a viral infection, caused by canine distemper virus, and is transmissible to dogs and some wildlife species, but is not zoonotic. Raccoons are very susceptible to distemper and infections and outbreaks are common. If raccoon rabies is present in the area, we need to err on the side of caution and treat an abnormal raccoon as potentially rabid until proven otherwise. If raccoon rabies isn’t in the area, an abnormal raccoon is generally assumed to have distemper (but remember that rabid raccoons can hitch rides on vehicles, so we can’t rule out rabies completely without testing).

But there is one other possible cause for a raccoon to be acting somewhat drunk… alcohol.

A story from last fall (yes, I’m a bit slow) in the Washington Post describes a rabies scare in West Virginia, where the raccoons were ultimately determined to have been intoxicated by alcohol. No, they hadn’t raided a liquor store – it turns out they’d been eating fermented crab apples.

Surprisingly (and good to hear), they weren’t euthanized right away because of their abnormal behaviour. Just like we do for any other drunken mammalian species, the raccoons were held until they sobered up, and were then sent on their way. A picture of one of the young offenders was released by the Milton (W. Va) Police Department. It’s much cuter than the typical mug shot.

Drunk or not, it’s still a good idea to stay away from raccoons, especially in southern Ontario.

Canadian Pet Tick Study

By Scott Weese on Posted in Cats, Dogs

We’re getting ready to launch the Canadian Pet Tick Study, with funding from the OVC Pet Trust. We’ve had great response from veterinarians in Ontario, but need more clinics from other provinces, so please share this link with out-of-province veterinary colleagues who may be interested! Details are available here:

https://www.petsandticks.com/news/calling-all-veterinary-clinics-join-the-canadian-pet-tick-survey

Rabies in a dog, Ontario

By Scott Weese on Posted in Dogs, Rabies, Vaccination

It’s easy to get complacent about rabies, even when you live in an endemic region. While we have ample bat rabies, Arctic fox rabies and raccoon rabies in Ontario, spillover into domestic animals is relatively rare. Success can breed complacency, though. When control measures work, it’s easy to forget why they are so important.

That’s my rambling but somewhat relevant introduction to a case of rabies in a dog in Ontario. The dog, from Wainfleet, Ontario, is the first canine rabies case in the Niagara region in over a decade. Contact tracing is underway to determine if any people need post-exposure prophylaxis and if any other domestic animals might have been exposed to the dog.

Typing of the rabies virus is presumably underway to determine what strain it is. We don’t have canine rabies in Canada (i.e. a rabies virus strain that is adapted to circulate in the dog population). This is presumably spillover from raccoon-variant or bat-variant rabies. Raccoon-variant rabies in this dog would be a likely given where the dog lives and the gradual spread of the virus into this region over the last few years from the outbreak that started in Hamilton in Dec-2015. Spillover into domestic animals and potential exposure of people is a reason the outbreak is a major concern, and why a lot of time, effort and money are being spent to try to eradicate terrestrial rabies again from southern Ontario.

While rabies is rare in domestic animals here (and in many regions), the threat still exists. Vaccination of pets is important to protect the animal and prevent spillover of wildlife rabies into people. More information about rabies can be found on the Worms & Germs Resources – Pets page.

Streptococcal infection from a horse

By Scott Weese on Posted in Horses

A common limitation of studies or case reports of zoonotic pathogens or infections is that they are one sided – they often just discuss the human case(s), or they just report carriage of a pathogen in animals. Case reports of human infections often only go as far as saying something along the lines of “this bug is most commonly associated with dogs, so the person must have been infected by the pet dog.” Those are usually reasonable assumptions in most cases, but they’re still assumptions. Sometimes, it’s not possible to properly investigate the animal link. Most often, no one bothers.

A recent paper in Emerging Infectious Diseases (Sleutjens et al. 2019) shows what can/should be done when investigating suspected zoonotic infections. It’s a report describing a human case of endocarditis (infection of the inner lining the heart, typically involving heart valves) caused by the bacterium Streptococcus equi zooepidemicus (Strep zoo for short).

The patient was admitted to hospital with malaise and a fever, and infection involving a prosthetic aortic valve that was placed 9 months earlier was noted. Strep zoo was isolated from the patient’s blood, which facilitated appropriate and effective treatment. The patient was discharged from hospital 6 weeks later.

As you can probably guess from the “equi” part of the name, this bacterium is commonly found in horses. (It’s less commonly found in other animal species like dogs and cats, and rare human infections have been associated with those species too.) An investigation of possible sources was performed, and since the patient had frequent contact with 7 horses that were stabled at his yard, those horses were tested. Two of the horses had had upper respiratory tract infections around the time the patient got sick. Whether that’s relevant or co-incidental isn’t clear, since Strep zoo can cause respiratory tract disease in horses, but most often is found in healthy horses. Regardless, the bacterium was isolated from 4 of the 7 horses.

What sets this investigation apart from most others is the additional testing that was done. They performed whole genome sequencing (WGS) of the bacteria isolated from the horses and the patient. Not surprisingly, they were  essentially the same, pretty much confirming that the horses were the source of infection. The figure below shows how the human isolate, in grey, is closely related to (and presumably originated from) the horse strain at the centre of the collection.

Strep zoo infections in people are rare, but it’s important to understand how, when and why bacteria move between species.

As the authors concluded “Systematic reporting of suspected or confirmed transmission of pathogens between horses and humans is lacking. Such reporting would support the estimation of the burden of equine-origin zoonotic infections in humans, which is needed as the equine industry continues to grow. Collaboration among disciplines to develop such a reporting system is fundamental for enabling reliable assessment of the potential risk for humans to become ill after contact with horses and the usefulness of implementing precautionary measures for patients with specific conditions.”

This report doesn’t mean horses pose any more risk now than they did before. It’s just a reminder that uncommonly, infections like this can occur.

In addition to the reporting need that the authors of the paper identify, a key step is even considering zoonotic infections. “Do you have pets or have contact with animals?” isn’t asked enough when people go to the doctor. Most of the time it’s not relevant, but occasionally it’s very relevant, and if the question isn’t asked, zoonotic infections can be missed (sometimes with fatal consequences).

Leftover zoonotic disease Q&A, Part 2

By Scott Weese on Posted in Cats, Dogs, Rabies, Vaccination

Here are some more leftover questions from the talk I did a talk recently for Third Age Learning in Guelph:

As West Nile virus seems to be spreading, is there a vaccine becoming available for the general population?

Probably not, but that’s just a guess.  While it should be possible to make an effective human vaccine, I suspect companies aren’t lining up to do it.

We have an effective vaccine in horses, so why not people?

It’s a lot easier and cheaper to get an animal vaccine licensed. People are probably also more willing to vaccinate their horses than themselves for a rare disease like this (especially when you consider how low flu vaccination rates are, despite how common flu is and how many people it kills).

So, I suspect this is a situation where it would be technically feasible to do, but from a market standpoint, it’s just not practical.

A raccoon was trying to get into some stores at Speedvale Mall on Sunday. What can one do?

Stay away. I don’t mean run screaming from the raccoon, but don’t touch it.

It was probably a normal raccoon doing what raccoons do… looking for food.

It’s hard to know the exact context from the question.  If the critter walked in the front door and was cruising through the public area, unconcerned about people or looking otherwise abnormal, I’d be concerned. Since raccoon rabies has yet to be found in Guelph, but it’s not too far away, we’re in an area where surveillance is important. Testing of the raccoon might be performed if it was caught. Catching it is the issue. The provincial ministry in charge of rabies in wildlife is the Ministry of Natural Resources (MNRF).  The provincial agriculture ministry (OMAFRA) helps veterinarians deal with domestic animal exposures. Public health deals with human exposures. But in all cases, the animal needs to be captured and euthanized (or found dead) before it can be tested, and the only agencies equipped to deal with a live animal are local animal control.  In the absence of something that indicates the raccoon is acting abnormally, I’d just steer clear.

I have two indoor cats that have never been outdoors except to visit the vet. Why do they need annual rabies shots?

This is a very common question. My initial (somewhat flippant) response is “you’d be amazed at how many “indoor” cats get hit by cars every year.” Some indoor cats never leave the house, but many sneak out occasionally. That’s a chance for rabies exposure. Even those that never leave the confines of their house can be exposed to rabies virus, as I know from personal experience with a rabid bat.  It happens far more often than people realize, even in apartment buildings in the middle of the city.

Vaccination is important to protect indoor cats against rabies, even if the risk of exposure is low. Another thing to consider is the response to exposure. In Ontario, a vaccinated cat that gets exposed to rabies but gets a booster vaccine within 7 days does not require a formal quarantine period. An unvaccinated cat gets a 3 month quarantine if it receives a rabies vaccine within 7 days and a 6 month quarantine if it doesn’t get boosted in that time frame.

We dose our dogs to prevent tick bites. Is there anything for humans in the future?

I have to assume companies are looking into this. We have very effective tick preventive medications for dogs and cats. As mentioned above, it’s much easier to get a drug licensed for animals. Unlike a vaccine, lots of people would probably be interested in an oral or topical product that repels or kills ticks, if it was safe and effective. Wariness of putting “chemicals” into their body would dispel some, but I imagine there would still be market. Whether that market justifies the millions of dollars in drug development costs is presumably something companies have assessed.