Worms & Germs Blog

Dog Licks…Again

Posted in Dogs, Other diseases

Every year or so, there’s a new wave of publicity/paranoia about the risks associated with dogs licking people. Often, it follows a study of bacteria that can be found in the mouths of dogs. It leads to a combination of balanced reports, sensational reports and defensive responses.

What is the concern?

Dog’s mouths are vats of billions of bacteria from thousands of different species. Some of those species can cause disease in people. Licking can be an effective way to transfer some of those.

What is the real risk?

That’s the tough question. Dogs like people all the time. Very few people get sick. Every dog has something in its mouth that could kill a person in the right situation. The same could be said every person’s mouth (as well as lots of door knobs and other sites). We get exposed to disease-causing bacteria very often..probably multiple times a day.

The overall risk is low, but there is some risk and it’s wise not to ignore it.


Risk reduction is the key.


Are some situations riskier than others?

  • Yes. The implications of exposure to bacteria in dog saliva are higher in some groups. Those consist largely of:
  • People that have compromised immune systems
  • People that don’t have a spleen (that’s related to immunocompromise but is a noteworthy group because of the risk posed by the bacterium Capnocytophaga canimorsus)
  • The very young (<5yrs of age) and elderly.
  • Pregnant women

Some additional situation pose increased risk

  • Licking broken skin
  • Licking mucous membranes….mouth, nose, eyes
  • Licking around invasive devices (e.g. people with an indwelling catheter)
  • Licking around the ears (especially in young kids)

What about the dog?

People aren’t the only ones that get exposed to bacteria when a dog licks them. Dogs can pick up bacteria from the person. We’ve previously shown that being allowed to lick people is a risk factor for hospital visitation dogs acquiring MRSA (methicillin-resistant Staphylococcus aureus)

What’s the take home?

  • For me, it comes down to a few basic messages
  • High risk people should not be licked by dogs.
  • Dogs that are sick, eat raw meat or have other risk factors for carrying resistant bacteria create some added risk.

The basic themes apply to more than licking, but to various potential diseases and disease exposures…..high risk people need to know they are high risk and they need to take some extra precautions; low risk people need to think about the cost/benefit. If you’re low risk and you like dog’s licking you, go for it. If you don’t like it, why add some degree of risk.

The risk posed to the average person is quite low. Personally, I don’t like my dog licking me. That being said, if he catches me by surprise and licks me, I don’t run screaming from the room and douse myself with alcohol.

“Kittens Can Cause Death” and Other Overblown Headlines

Posted in Cats

kitten-with-toyI’ve held off writing about this, but needed to get to it sooner or later. A recent article in the journal Emerging Infectious Diseases  (Nelson et al 2016) has spurred a serious of over-exaggerated and sometimes downright comical headlines. “Kittens can cause death; US study” is an Australian example of over-the-top reporting, probably by people who didn’t really read the manuscript.

The paper is a study of cat scratch disease (CSD), a bacterial infection caused by Bartonella henselae. Cats are the main reservoir for this bacterium, which is spread between cats by fleas. The bacterium can live in the cat’s bloodstream for prolonged periods of time without causing any problems for the cat.  As the name of the disease implies, cat scratches are a main route of exposure for people, but fleas play a role as well.  The fleas ingest the bacterium in the blood when feeding on the cat, and then pass it in their feces. People can be infected if a scratch gets contaminated with Bartonella-ladden flea feces, inoculating  the bacterium into the body. Cat bites might also play a role, as another way to inoculate a person with infected flea poop, or potentially even infected blood directly from the cat. Most often, inoculation of the bacterium probably doesn’t do anything – the body simply fights it off and produces antibodies against the bug. However, disease can obviously occur too depending on the circumstances.

This CDC study evaluated CSD in the US by looking at a health insurance claims database. The findings are different from some previous studies and perceptions, but not evidence of impending doom. Here are some highlights:

  • The average incidence of CSD was about 4.7 per 100,000 people.
  • There was a steady decrease in cases of CSD that did not result in admission to hospital (outpatient visits) over time, from a high of 5.7/100,000 in 2005 to 4.0/100,000 in 2013.
  • Not surprisingly, areas that tend to have lower flea populations had fewer CSD cases.
  • The highest incidence was in kids 5-9 years of age, at 9.4 /100,000. Overall, kids less than 14 years of age accounted for about a third of cases. (One thing to note is that the database did not have information on people over 65 years of age. They are another potentially increased risk group and one that would likely be at higher risk of being hospitalized from CSD).
  • Overall, most cases occurred in the southern US in the late summer and fall.

Much of what was reported in this study is consistent with what we already know. The distribution of disease across the US and the highest risk times of year are what would be expected for a flea-associated infection. The estimate of the incidence of disease is higher than some studies and lower than others. The incidence of hospitalization was a lot lower than other studies.

What does this study tell us, in the big picture? It’s a reminder that CSD is uncommon but still something that warrants attention, particularly as cat ownership increases. Bartonella henselae is a strange bug that is increasingly associated with problems other than CSD, so measures to reduce exposure (and ensure accurate diagnosis) are important.

Some take away messages:

  • Like many diseases, children are over-represented. This may be, in part, biological (being at greater risk of disease after exposure). However, a lot of it is probably due to an increased risk of kids being scratched or bitten by cats. Good supervision and education of kids about how to act around cats can reduce the risk.
  • This is one more reminder of the importance of flea control.

Controlling fleas and avoiding bites and scratches can make this a largely preventable disease.

Infectious Diseases and Canine Group Settings

Posted in Dogs

Canine group health symbol OSUThe Ohio State University has launched a new website about infectious disease risks in canine group settings. The site includes a comprehensive document on risk and risk reduction strategies (which was just published last month in the Journal of the American Veterinary Medical Association), as well as owner-level fact sheets and a risk calculator to help identify specific risks (and responses) in individual situations.   The site is designed to help evaluate, understand and ideally reduce infectious disease risks that are inherent whenever multiple animals (or people) get together.  We’ve also posted the links to several of these resources on the Worms & Germs Resources – Pets page.


Updated Equine West Nile Virus and EEE Maps

Posted in Horses

The title says it all. Here are the most recent maps from WormsAndGermsMap showing equine cases of West Nile virus and Eastern Equine Encephalitis (EEE) virus infection. As with any surveillance, the maps only capture a percentage of the true number of cases, but looking at the geographic distribution and trends in date-of-onset can still be informative.

West Nile cases in horses as of 28-Sep-2016

West Nile virus

Eastern Equine Encephalitis (EEE) cases in horses as of 28-Sep-2016

Eastern Equine encephalitis

The Indoor/Outdoor Cat Debate

Posted in Cats, Salmonella

Outdoor catThe latest edition of the Journal of Feline Medicine and Surgery contains an American Association of Feline Practitioners (AAFP) position statement entitled “Impact of lifestyle choice on the companion cat: indoor vs outdoor”. (The document is actually an update of the previous 2007 position statement “Confinement of Owned Indoor Cats“.) It’s an interesting position statement that tries to balance a lot of issues. There are various arguments both ways, involving health, welfare and behavior. Some people vehemently oppose cats being outdoors because of the number of birds and rodents that they kill, or because they can be injured or killed by vehicles and predators. Some think they’re born to roam. However, let’s just focus on the infectious diseases and zoonotic diseases aspects here.

Zoonotic Diseases

This one’s easy. There are lots of potentially zoonotic bacteria and parasites that cats can acquire outside, from hunting birds and rodents, picking up fleas and encountering other animals. These include things like Salmonella, Toxoplasma and Bartonella. Indoor cats are at much lower risk of shedding many of these zoonotic pathogens. They are also less likely to be injured, reducing the chance of wound infections that might be zoonotic.

Keeping cats indoors is one of my standard recommendations when there are high risk people (e.g. people with compromised immune systems) in the house.

Feline Infectious Diseases

This one’s pretty clear too. It’s logical. The fewer individuals a cat (or anyone else) encounters, the lower the disease transmission risk. Cats that get outside have a greater risk of exposure to diseases from other cats (e.g. feline immunodeficiency virus (FIV)), insects (e.g. plague in some regions) and prey (e.g. Salmonella). Outdoor cats also get into more fights and not uncommonly end up with cat bite infections or abscesses. The risks are heightened in cats with compromised immune systems and some other illnesses, just like they are for people with compromised immune systems.

Ultimately, while it’s clear that keeping cats indoors reduces infectious disease risks both for the cats and their human contacts, there’s no simple answer to the indoor vs outdoor question. Some people are adamant that cats should be indoors only. Some are adamant the other way. Both groups have good arguments, but sometimes forget the individual aspect… the cat itself.

Myself, I have both. We have Finnegan, a purely indoor cat. This summer, we also adopted two cats as part of the Guelph Humane Society’s Barn Cat Adoption Program. Those two wouldn’t do well indoors (and Finnegan would probably start peeing everywhere if we tried). They live outside (although one, Rumple, has become more of a deck and garage cat). Yes, it increases their risk of diseases and attacks from coyotes and other animals. Yes, they’ll kill some birds and other wildlife. But for them, it was outdoor living or euthanasia.

It’s a complex situation and I know I’ll get strongly opinionated comments in response to this topic. In my perfect world, all cats would be indoors, but not all cats fit into my perfect world. So, I think the default should be keeping cats indoors whenever possible, both for their health and the health of their families. That’s particularly important when the people or cats are at increased risk of disease. But, some cats won’t do well inside 24/7 and some allowances can be made for them as well, in the right situations.

The indoor/outdoor decision needs to be made based on a large number of factors and there’s no single approach that works for all cats, households and regions.

The position statement can also be found on the AAFP’s website: http://www.catvets.com/guidelines/position-statements/lifestyle-choice-position-statement

Rabies Posters & Latest Update

Posted in Rabies, Vaccination

MNRF_rabies_poster_protect_2016_emailRaccoon-variant rabies cases around the Hamilton area continue to trickle in slowly but steadily each week.  The total number of cases is now up to 187 since December 2015, with 132 cases in raccoons and 53 in skunks.  The remaining two cases were in less common – but not altogether unexpected – species: a fox and a cat.  Both were almost certainly exposed to the virus through contact with a positive raccoon or skunk. Although there is also fox-variant rabies in Ontario (most recently two cases found in the same area of Perth county between December 2015 and March 2016), this fox was from the Hamilton area and the virus was typed as raccoon-variant. It’s very important to remember that all mammals are susceptible to all variants of rabies virus (including bat-variant), the names we give the variants simply reflect the species in which each “strain” circulates most commonly.

The rabid cat was the first rabid cat found in Ontario since 2012.  It was a stray cat from the Hamilton area, but it was taken to Haldimand before it got sick, by someone who wanted to adopt it.  This is a relatively small-scale example of how well-meaning individuals can inadvertently help diseases move long distances very quickly (the same thing can also happen with rescue dogs from other countries, with both rabies and other diseases).  Fortunately the veterinarian who saw the cat was aware that there was rabies in the area, and knew to contact the local public health unit in this case, because there was at least one person who was exposed to the cat’s saliva.  Once the test result was known, OMAFRA also assisted the local veterinarians with recommendations for management of any pets that had potentially been exposed to the cat.  The public health unit has ensured that any exposed people are provided with post-exposure prophylaxis (PEP).  Stray, ferral and community cats are often unvaccinated and are at increased risk of exposure to wildlife (some of which they may even compete with for food sources), and they can pose an increased risk of rabies transmission to people because of increase contact with humans who feed them or otherwise encounter them.

The City of Hamilton, with the help of ten local veterinarians and many other volunteers, has organized a large public rabies vaccination clinic for tomorrow (September 17).  They are hoping to vaccinate 500 cats and dogs.  Owners can bring their pets to Gage Park from 9AM-3PM and have them vaccinated for rabies for $25 each.

The Ministry of Natural Resources and Forestry continues to test wildlife from the surveillance zone that are either found dead or euthanized due to illness or unusual behaviour.  They have also produced two new posters for the public about Protecting yourself and your pets and Rabies vaccine for wild animals (the later is specifically for people living in the zones where the MNRF is distributing oral rabies vaccine (ORV) baits for wildlife).  Printed copies of these posters are also available through the MNRF.

Rabid bats also continue to be found periodically throughout Ontario, which is not unusual as it is well known that rabies is endemic in the bat population at a very low level.  That’s why it’s always important to avoid contact with bats (and to vaccinate even indoor cats – because bats can and do get inside periodically!).

The latest terrestrial case maps and maps of the baiting zones can be found on the OMAFRA rabies website (along with lots of detailed information for Ontario veterinarians), as well as the Ontario.ca rabies website on the “rabies in wildlife” page.

Dog Bite Prevention Education

Posted in Dogs

I spend a lot of time talking about “emerging” infectious diseases. Some of these are truly emerging (i.e. new) diseases, some are conditions we couldn’t diagnose well before but now recognize more easily, and some are disease that have been there all along and are just getting more attention. However, while emerging infectious disease (especially zoonotic diseases) attract attention, we can’t ignore the “run-of-the-mill” problems.

Case in point: animal bites.

Bites are the most common animal-associated illness, and often lead to infection from bacteria in the animal’s mouth or on the person’s skin. A large percentage of bites are preventable, with education, training and supervision.

While we don’t want to blame the victim, there needs to be an onus on people to help protect themselves. I’m not always a fan of infographics and posters (since I’m not sure most really achieve anything) but here’s a bite-prevention poster from Spokane County (Washington State, US) that I really like.


Infectious Disease Risk Management for Canine Group Settings

Posted in Dogs, Other diseases

vintage-kennel-club-dogsHot off the presses in the Journal of the American Veterinary Medical Association (JAVMA) is a guidance document aimed at reducing infectious disease risks in a variety of canine group settings. The paper, Risk reduction and management strategies to prevent transmission of infectious disease among dogs at dog shows, sporting events, and other canine group settings (Stull et al, J Am Vet Med Assoc 2016) discusses a variety of issues, risks and recommendations. While we can never eliminate infectious disease risks, a lot of practical measures can be taken to lessen the risk, while still allowing for normal operation of a show, meet, kennel or similar event. The document can be downloaded by clicking the title above or directly through the JAVMA website.

Equine Arbovirus Update

Posted in Horses, Other diseases

Arboviruses (ARthropod-BOrne viruses) are viruses that are spread by insects, often mosquitoes. As I’ve written about recently, mosquito biology and differences in reservoir species mean that mosquito-borne viruses can have quite different patterns of distribution and spread. As is common, the occurrence of West Nile virus infection in horses tends to ramp up in late August and into the fall, and is broadly spread across North America. In contrast, Eastern Equine Encephalitis virus (EEE), while a cause of nastier disease, tends to have a more narrow geographic range, occurring mostly along the Atlantic and Gulf Coast regions in the US. West Nile cases in particular seem to be spiking lately. Check out  Worms & Germs Map (www.wormsandgermsmap.com) for the latest case maps. As always, these maps don’t show every case of disease, just those that are diagnosed and reported through various means, but they do provide an interesting snapshot of these two diseases.

Eastern Equine Encephalitis in horses, last update Aug 30, 2016

EEE copy

West Nile virus in horses. Last updated Aug 30, 2016.

WNV copy

Vague Disease Warning in Dogs (and Cats?) in New Jersey

Posted in Cats, Dogs

Sleeping pupA vague but potentially interesting report from New Jersey outlines a request for information about pet deaths in the area.

The Cumberland County [New Jersey] Health Department is asking for the public’s help in collecting data on reports of what it calls “sudden and unusual illness” among dogs in the county.

  • Perhaps the most interesting and important part is that the Health Department is leading the charge. Too often, there’s little interest from the human-health types in situations like these.

Officials say sometimes these illnesses are chronic and sometimes they can come on suddenly. The county health department, in collaboration with the New Jersey Department of Health Zoonotic Disease Unit, announced on Friday that it is collecting information from those dog owners that feel their pet’s recent illness falls into this category. Although most of the concerns have been regarding dogs, the county officials said in a news release, they would not exclude information regarding severe and unusual illnesses in cats. Health officials say they encourage pet owners to consult with their veterinarian if they see signs of their dog or cat falling suddenly ill.  Signs of illnesses in dogs can included lethargy, vomiting, diarrhea, refusal to eat and muscle weakness.

According to a health department spokesman, “a handful of dogs” have been reported ill, mostly in the Millville area.

In the past week three of those have died. Among them was one dog which was older and displayed symptoms of pneumonia.

The health department is asking for the public’s health in gathering information as a proactive measure to determine whether, in fact, there is a widespread problem.

While the department is currently focusing on the collection of information regarding recent illnesses in dogs, we encourage residents to always reach out to a veterinarian regarding any unusual and sudden illnesses any type of pet exhibits. 

Reports like this come out in the press occasionally. These can be:

  1. True new problems
  2. Outbreaks caused by existing and well know pathogens
  3. Misinformation or over-reaction

All of these happen, but #3 is probably the most common, followed by #2. I often get involved in investigating reports like these, and it’s usually frustrating (and fruitless) because of a lack of clear information. So, from that standpoint, getting the word around to as many people as possible is very useful.

The information that’s provided is pretty vague in this case, probably because they have little information to go on.  Unfortunately, this can ramp up unneeded concern because pretty much any sick dog or cat could fit this description.

While the information is vague and the response isn’t clear, this type of approach can be useful if owners are paying attention and officials are collecting good information. Early response is key to controlling infectious diseases, and it’s much better to over-react occasionally than to wait until there’s definitely a problem, at which point control may be much more difficult.

Key actions for a situation like this are:

  • Raising awareness: this report is a good start.
  • Collecting information about sick animals (what’s wrong, where they have been, what testing has been done): this requires some work but it sounds like they’ll be tracking at least some of this.
  • Collecting samples for testing to identify a cause: this is where things sometimes fall off the rails. Diagnostic testing can be expensive and often we don’t have many test results to evaluate. That’s particularly true when testing may not influence care of the animal.  Most people aren’t into paying for testing for the “greater good” if it won’t help their pet.
  • Engaging experts in veterinary infectious diseases and infection control: this is important to help determine potential causes, identify potential control measures and figure out how to arrive at a diagnosis (and maybe identify a new cause).