As expected, the KW humane society ringworm outbreak has gone from "we’ll be open in a couple days" to "it may take months to clear it up."

The scope of the outbreak isn’t really clear from press reports, but "a couple" of other animals now have signs of the skin disease. Investigation of the timing and likely sources of exposure of new cases is crucial. They may just be animals that were infected early, before the problem was recognized (the best case scenario) but investigating these "new" cases is very important because if these animals were exposed after the outbreak was identified, then there are problems with containment.

Shelter personnel have declared that they aren’t planning on euthanizing more animals, but the shelter remains closed for adoptions. Stray animals will continue to be accepted. This creates a tricky situation where new animals (e.g. fuel for the fire, if things aren’t under control) come in and can actually propagate the outbreak. It also creates overcrowding issues since the shelter was probably pretty full to start with, and continuing admissions with no adoptions can’t be maintained for long. The shelter is looking at renting units in which to put animals – this is a relatively common approach for creating more contained spaces, and one that can be useful if good infection control practices are in place (although I’ve seen too many outbreaks where the offending pathogen quickly makes its way into the new units). Clear policies, sound training, careful supervision, exquisite planning and good communication are critical for making a situation like that work.

While the shelter has gone from an unrealistically optimistic time frame to a warning about long-term efforts, as with most things in life, the middle ground is usually the most accurate. Ringworm outbreaks can’t be declared over in a few days (it’s possible to contain it in a short period of time, but not declare an outbreak over). A few days isn’t even enough time to get culture results back to figure out exactly what’s happening. Testing, isolation, cohorting, mass treatment, evaluation of training, evaluation of infection control practices, and similar measures are needed, but if done right, an outbreak can be contained in a reasonably short period of time. Given the need to repeatedly treat all animals (affected animals are being bathed every three days with a medicated solution) and the time lag for ringworm culture, it’s going to take at least a few weeks, but let’s hope this outbreak ultimately gets measured in weeks rather than months.

A short distance down the road from here, the Kitchener-Waterloo Humane Society has been quarantined because of an apparent ringworm outbreak. There’s no information on the facility’s website and information in the press has been pretty vague (both concerning aspects), but it sounds like a ringworm outbreak. Adoptions have been ceased and the Humane Society will apparently "reassess its safety protocols by the end of the week.The outbreak appears to have been going on since at least last week, so hopefully they’re getting on this and have a strong outbreak investigation and control plan in place.

I haven’t been involved in this outbreak so I know nothing more than what is in the press, but ringworm can be a big problem in shelters. It’s a controllable disease, but the situation can get completely screwed up with a poor outbreak response. It’s also sometimes an overblown problem (or not a true problem at all) in some situations, so it’s critical that the outbreak is properly investigated and managed. That’s not always the case, and the consequences can be serious.

There are a lot of factors that go into good outbreak management that are hopefully being done at the KW Humane Society. These include:

  • Good communication both internally and externally.
  • Transparency.
  • Sound containment practices.
  • Getting good advice.
  • Actually listening to the good advice (and not bad advice).
  • Taking the time to do it right.
  • Ensuring one is acting on correct information.
  • Spending money where it needs to be spent, be it testing, treatment, personnel or other factors. Trying to save money during an outbreak response often ends up costing much more in the end.

The independent report of the 2010 ringworm debacle at the Newmarket OSPCA should be important reading for any shelter trying to figure out what to do, and what not to do.

As with most "pocket pets," guinea pigs don’t get a lot of attention in the scientific literature. As a result, we are limited in what we know about certain diseases in this species, and we tend to rely a lot on personal experience, small case studies and extrapolation from other species. It’s not that these sources of information are bad, they’re just not a replacement for larger, more controlled studies.

A recent study in the journal Mycoses (Kraemer et al. 2012) provides a rather comprehensive overview of ringworm (dermatophytosis) in these little fuzzy critters. The authors surveyed 74 owners of guinea pigs with ringworm and veterinarians. Here are some highlights from the results:

  • 97% of ringworm infections were caused by Trichophyton mentagrophytes. Ringworm can be caused by a few different species of fungi, with a different organism, Microsporum canis, being most common in dogs and cats.
  • 43% of the time, a new guinea pig was introduced into the household in the weeks preceding the onset of disease, and around one-third of affected guinea pigs had been in the household for less than 3 months. That’s not too surprising, since new animals are often a prime source of infectious diseases. It shows the importance of ensuring that new pets are examined carefully and are healthy before they are brought into the household. It’s certainly no guarantee that there won’t be problems, since healthy-appearing animals can be shedding various infectious agents, but it helps reduce the risk.
  • Ringworm lesions were most common around the head. Hair loss was the most common sign, with scaling and crusting also common.
  • Signs of ringworm were also present in other guinea pigs in the household in over one-third of cases.
  • Various treatments were used and some animals weren’t specifically treated.  In fact, 7/8 of the guinea pigs that did not receive specific anti-fungal therapy got better. It’s known that ringworm can be self-limiting (meaning the animal will get better on its own over time). However, treatment can speed the process up and decrease the likelihood of transmission to other animals or people.
  • In 24% of cases, people in the household also had signs of ringworm, on the head, neck and arms. Children were most commonly involved. That’s not too surprising since kids probably had more contact and closer contact with the animals than their parents.

While not a severe disease, ringworm is a problem because it’s highly transmissible. It can easily and quickly spread between animals, and between animals and people, and elimination of ringworm from a highly contamination household can be a major hassle. Presumably the risk of widespread environmental contamination is less with guinea pigs compared to dogs and cats because of their smaller size and tendency to be kept confined to cages most of the time.

Ringworm should be considered in any guinea pig that develops hair loss or other skin/hair problems. This is particularly true if it’s a new acquisition or if a new guinea pig has been introduced to the household recently.

If ringworm is suspected, a prompt visit to the veterinarian is in order. The guinea pig should be handled sparingly (or ideally, not at all) until the cause of the skin disease is identified. Close attention should be paid to hand hygiene, and even the use of gloves could be considered, although gloves aren’t a cure-all and people sometimes misuse gloves to such an extent that they actually increase the risk of spreading disease.

If a new guinea pig is obtained, it’s ideal to have it examined by a veterinarian before it comes into the household. I’m a realist and realize this is unlikely, but it’s ideal. In lieu of that, it’s important to get a guinea pig from a reputable source, to ensure that other guinea pigs from the same source don’t have skin disease, and to carefully examine the animal for skin lesions before it gets home. It’s also ideal to keep any new guinea pig in its own cage for a couple weeks to act as a quarantine period and allow for identification of any incubating diseases.

If owners of an infected guinea pig develop skin lesions, they should be examined by their physician, and make sure the physician knows they have been in contact with an infected animal.

(click image for source)

A Kitchener, Ontario family is dealing with a household outbreak of ringworm, likely contracted from a new pet guinea pig. Ringworm is a fungal infection cause by a few different types of fungi. Some ringworm fungi are able to infect both people and animals, and those can be spread in households from direct contact with an infected person or pet. In this case, the Gross family purchased a new guinea pig from a local pet store, and unfortunately, ended up bringing ringworm home as a bonus.

As is common, the new pet was the centre of attention when it got home, and the Gross’ three children, ages 8, 5, and 2, had very close and frequent contact with it. The next day, the family noticed an area of hair loss on the guinea pig, at which point they took it back to the store. Ringworm was subsequently diagnosed, though there’s no mention of how this was done, nor is there any mention of what actually happened to the little critter afterward.

The big problems started a week later, when a red lesion was seen on their youngest child’s back. This was also diagnosed as ringworm, though again there’s no mention of how, or whether it was definitively confirmed as ringworm. The newspaper report goes on to say "More spots kept appearing on Matthew’s skin as Gross was given different steroid creams to try and contain the infection." You always need to take media descriptions of medical issues with a grain of salt.  Hopefully, the child was treated with anti-fungal cream, not steroid cream, as the latter not only won’t treat ringworm, they may make it worse if used alone. Steroid creams are often prescribed for non-specific skin issues (particularly if the skin is very itchy, which can certainly happen with ringworm), but in a case like this where there was known contact with an animal with ringworm, I have to hope that the physician was treating with an antifungal cream instead of, or in addition to, a steroid cream. 

Anyway, whether despite or because of the treatment, more skin lesions kept appearing on the child. Then skin lesions were found on the family dog, and both the dog and cat ended up being treated for ringworm.  The treatment for dogs and cats is relatively straightforward, but it’s still a hassle and can be somewhat expensive, and often takes several weeks.

The family has contacted the pet store about paying for cleaning supplies, air purifiers and veterinary bills, but the company did not respond to the newspaper reporter’s inquiries, citing an ongoing investigation. It’s hard to say whether the company should be held responsible. It largely depends on the measures they take to reduce the risk that they are selling pets at increased risk of transmitting infectious diseases. There’s always a chance of picking up something from a pet, so an infection does not necessarily indicate incompetence or liability. If a store had reasonable practices in place, it’s probably the purchaser’s responsibility to take proper precautions when they take the pet home, and it’s an example of why prompt veterinary examination of new pets is always a good idea. It’s rarely done, particularly for species that cost less than the price of a veterinary exam, and you never know whether it would have helped prevent anything in this case, but in many instances it can help identify potential issues and address them before problems occur.

Preventing outbreaks like this can be difficult. Ringworm can be found on animals in the absence of any skin disease, so you can’t always tell an animal is infected by looking at it. (However, in this case if a large patch of hair loss was noticed by the owners the day after the guinea pig came home, it’s likely that something was evident the day before). Ringworm is spread by direct contact, which is common between pets and kids, especially new pets that often get smothered with attention in the first few days. Good hygiene practices, particularly attention to handwashing, can certainly help, but some degree of risk will remain.

Overall, guinea pigs are relatively low risk for zoonotic diseases, but this report shows that even "low risk" pets can be sources of infection. Fortunately, while controlling ringworm outbreaks can take time and be frustrating, it’s not a serious disease and it is controllable.

More information about ringworm can be found on the Worms & Germs Resources page.

As many of you know, there was a large ringworm "outbreak" at the Newmarket (Ontario) OSPCA shelter in 2010 that led to a public outcry in response to plans to depopulate the shelter. In the aftermath of the event, an independent investigation was launched, headed by Mr. Patrick LeSage (former Chief Justice of the Ontario Superior Court) and Dr. Alan Meek (former Dean of the Ontario Veterinary College). The investigation involved a comprehensive examination of activities pertaining to the outbreak and shelter operations, in conjunction with relevant experts (disclosure: I was one of those).

The report of the investigation is now available, and covers important aspects such as whether an outbreak was actually present (short answer: no) and whether there were major problems in shelter operation (short answer: yes). Most importantly, it provides a comprehensive set of recommendations to improve the operations of the Newmarket shelter and OSPCA as a whole.

The report, in its entirety, was released today by the OSPCA and is available for download on their website. The report is on the site in multiple files: the main report is listed as "Index" and contains the ~90 page overview and recommendations. The expert reports, which might also be of interest, are tables D1-3, E, F and G.

The OSPCA has changed their plans for management of the ringworm outbreak that is ongoing in a Newmarket, Ontario shelter. Now, some (hopefully all) remaining animals will be fostered out to local veterinarians while the situation is being brought under control.

One question that has been asked widely in the press and by the public is why these animals haven’t simply been sent to foster homes. Particularly now, with all the attention, there would presumably be many people willing to take in these pets. However, putting animals infected or potentially infected with ringworm into foster homes is a controversial and potentially problematic situation, because ringworm can be spread easily to people and other animals in the household. Sending out an animal that is or may be shedding a zoonotic disease is a tricky situation, and one that can’t be taken lightly. Additionally, proper management of these animals can take significant time and effort.

A better approach is to send the animals to places where they can be properly, safely and humanely isolated and treated. Veterinary clinics are a logical option, and a request has been sent to clinics in the area to take animals for quarantine and treatment. The reason veterinary clinics are being solicited is that many clinics have the ability to properly house these animals in isolation units and have the expertise and commitment to properly treat them.

Nonetheless, this is no small favour to ask of these veterinary clinics.  Just as taking an infected pet into a household carries some risk, taking these animals into a clinic is also associated with some risk of transmission to people and other animals. However, with proper facilities and protocols, and the donation of sufficient personnel hours to implement those protocols, the risks should be minimal. To facilitate this, we have developed an information sheet with infection control and treatment recommendations for veterinary clinics. For anyone else who is interested, the document can be found here and on the Worms & Germs Resources page under Information Sheets For Veterinarians.

Image: Ringworm lesion on the face of a cat (photo source: A. Yu, used with permission).

Never a dull moment…

This morning the Toronto Star published an article about the intended euthanasia of 350 animals at a humane society in Newmarket due to an ongoing ringworm outbreak.  This was quickly followed by another article about the same event that gave a few more details, including some comments from the OSPCA chief executive officer Kate MacDonald, who confirmed that the euthanasias had begun.  A "very aggressive strain" of ringworm and "human error" (related to a breakdown in protocols) are currently being blamed for this morning’s actions.  A lot of people are (understandably) very upset.  No one ever wants to see an infectious disease outbreak come to something like this.

I’m hesitant to comment too much at this stage, because we still don’t have all the facts – apparently even the duration of the outbreak is unknown.  No one has said if all 350 animals are infected (or what percentage of them are), nor how many other animals are present at the shelter. We also don’t know what’s already been tried in terms of controlling the outbreak.

A few facts about ringworm (dermatophytosis) that people need to remember:

  • Ringworm is a skin infection that can be caused by several species of fungi.  It is not a "worm" at all.  It is also very easily transmitted by direct or indirect contact with infected animals – their fur, their cages, their blankets, or anything else that may be contaminated with infected skin cells or hair.  Such infectious material can even be spread over short distances (e.g. room to room) in dust that is stirred up into the air.
  • Ringworm is transmissible to people, so with a large outbreak there are also issues with staff safety, and concerns with adopting out infected animals.  For most people ringworm infection may cause itchy, uncomfortable skin lesions, but for higher-risk people (e.g. very young children, the elderly or immunosuppressed individuals) the infection can be much more serious.
  • There are also a lot of animals (particularly cats) that carry ringworm without showing any signs of infection. If the Newmarket shelter has 350 animals with clinical signs of ringworm (a detail about which we have no information right now), that’s pretty bad, but even the animals who don’t appear to be infected may be carrying the fungus and could spread it to others.
  • Crowding, close contact and warm, humid environments are all factors that increase the risk of ringworm transmission. These are also all factors that are very hard to control in a crowded animal shelter.
  • Ringworm is treatable, but it is not cheap or easy. Animals typically require systemic therapy (usually oral medication, which can be very expensive particularly in large dogs) as well as whole-body topical therapy (e.g. dips, shampoos, sprays), and they need to be treated for several weeks. Decontamination of the environment at the same time is critical to prevent reinfection.

Cleaning up a ringworm outbreak at a shelter with at least 350 animals is no small undertaking.  The second article in the Star also describes personnel at the shelter this morning wearing "white hazardous material suits, latex gloves and plastic covers over their shoes", which would be considered reasonable precautions for entering a highly contaminated environment.

I’m sure we’ll hear more about this in the days to come, and hopefully that will include more details about why the mass euthanasia was deemed necessary by the OSPCA.

For more more information about ringworm, download the information sheet from the Worms & Germs Resources page, or check out our archives.

Photo source: yorkregion.ontariospca.ca via www.thestar.com

If your veterinarian suspects your pet may have ringworm, there are several different ways he or she may test for the causative fungus (a dermatophyte) on your animal’s fur and skin.  Some of these techniques are more useful than others in different situations.

  • Wood’s lamp:  A Wood’s lamp is simply a special ultraviolet light.  Approximately half of all Microsporum canis strains (the most common species of dermatophyte that causes ringworm in cats and dogs) will fluoresce blue-green under such a light. This type of testing is obviously very easy to perform.  However, other debris in an animal’s hair coat may fluoresce as well, and other species of fungus that cause ringworm do not fluoresce, so this test is not useful by itself in most cases.
  • Microscopy: Sometimes ringworm fungus can be seen on hair shafts from an infected pet when examined under a microscope.  However, it is easy to confuse other debris and structures for dermatophytes.  Also, not every hair on an infected animal will carry the fungus, so it’s possible to miss the infected hairs altogether with this test.
  • Fungal culture: The best way to diagnose ringworm is to culture the fungus from the infected individual (person or animal). In animals, one of the best ways to collect a sample for culture is to comb over all the fur and skin with a new toothbrush, and then try to grow dermatophytes from the toothbrush. This allows the fur from all over the animal to tested, rather than just one little clump of fur plucked from one area.  It can also make it easier to get a sample from the face and paws of cats, which is where these animals often carry the fungus.  Although fungal culture is the best way to diagnose ringworm, remember that fungal culture takes much longer than bacterial culture – instead of days, it may take up to three weeks to grow some dermatophytes.

It’s also important to remember that dogs, and more often cats, may carry dermatophytes on their fur even when they look healthy.  A positive fungal culture from an animal with skin disease, particularly a cat, does not necessarily rule out other diagnoses, so your veterinarian may still recommend other tests as well.  However, any animal with ringworm should be treated to prevent spreading the infection to other animals and people.

More information about ringworm is now available on the Worms&Germs Resources page, and in our archives.
 

For more information on ringworm, see the Worms & Germs post Ringworm: Skin fungus by any other name.  The photos here show ringworm lesions on a person’s arm and on a cat’s face, respectively.  (Photo credits: A. Yu, Ontario Veterinary College)

Over the past several years, studies have shown that many environmental disinfectants sold and labeled for use against the fungi that cause ringworm (which are called dermatophytes) in animals and people are, in fact, not effective when used in households and veterinary clinics.  The problem is the chemicals are typically tested against a suspension of the organisms in a test tube, but in the “real world” the fungi are usually found on small fragments of infected hairs.  Its possible that the hair shaft protects the fungus from the actions of some disinfectants.

There are a few disinfectants that have been shown to be effective against dermatophytes even when they are found on infected hairs and skin cells in the environment.  The most readily available one is household bleach, used at concentrations of 1:10 to 1:100.  Other effective products include Virkon-S® (a detergent-peroxide based product) and Peroxigard® (an accelerated hydrogen peroxide product) . An environmental spray containing enilconazole (an antifungal agent that is also found in the topical medication Imaverol®) was also found to be very effective. This product is not approved for household use, but it is approved for use in catteries. It is also licensed as a topical treatment for dogs and horses in most of Europe and Canada.

Eliminating ringworm from the household or clinic environment can be difficult, because the fungus can be found anywhere that an infected animal (or person) sheds hair or skin cells.  Here are some guidelines for environmental disinfection of dermatophytes:

  • All bedding, brushes, combs, rugs, cages, etc. should be vacuumed, scrubbed, and washed with hot water, detergent, and 1:100 chlorine laundry bleach, or another effective disinfectant (see above). It is best to throw out any items that cannot be thoroughly disinfected.
  • Walls, floors, lamps, etc. should be scrubbed and cleaned in a similar manner.
  • Carpeted areas may be impossible to effectively decontaminate. If possible, remove the carpet and either wash in hot water and bleach, or discard it. Otherwise, frequent vacuuming with immediate disposal of the collection bag is necessary.
  • Vehicle interiors should be decontaminated as much as possible in a similar manner.
  • Curtains can be “dry-cleaned” at a professional cleaner.
  • Clean heating vents (from the house furnace) as well as possible. If the house is heated by hot air, change the furnace filter once weekly throughout the decontamination process.
  • Cleaning and disinfection of the environment should be repeated at least once every 4-6 weeks (the more often, the better) until all affected animals and people have eliminated the fungal infection.

Obviously, environmental clean-up for ringworm is quite an undertaking.  If infection can be identified early, lesions can potentially be kept covered and movement of pets can be restricted to reduce the extent and amount of environmental contamination.

Special thanks to Dr. Anthony Yu (one of the veterinary dermatologists at the Ontario Veterinary College) for providing much of the information in this post, as well at the photos.

Ringworm infection is not caused by a worm at all – it’s actually a skin infection caused by certain kinds of fungus called dermatophytes. The scientific name for ringworm is dermatophytosis, or dermatomycosis. Some of the more common zoonotic species of dermatophytes found in animals include Microsporum canis, Trichophyton verrucosum, T. equinum, and T. mentagrophytes. There are also some dermatophytes that are primarily transmitted from person to person that are not carried by animals. These include the fungi that cause athlete’s foot and jock itch.

Like many fungi, dermatophytes grow best in warm, moist environments, but they can grow almost anywhere on the body. They tend to grow around hairs and in the superficial layers of the skin, and the infection can be quite itchy. A ringworm skin lesion tends to spread out from one point on the skin, causing hairloss as it progresses, resulting in a bald patch (see picture right). The outside (most active) edge of the infection often appears as a red ring, from which "ringworm" gets its name.  The centre of the lesion may begin to heal, and the hair may start to grow back, even as the bald patch gets bigger.  It may take anywhere from a few days to a few weeks for visible lesions to develop after a person or animal has been infected. (Photo credit: A. Yu, Ontario Veterinary College)

Ringworm is quite contagious. The fungi are present in the large numbers on hair and skin cells that are shed by infected individuals. People or animals can be infected through contact with these infected hairs and skin cells, either directly on the affected person or animal (i.e. direct contact), or on things like clothing, blankets, hairbrushes etc. that have touched the affected skin (i.e. indirect contact).

Ringworm occurs all over the world, but no one knows exactly how common it is because there are so many different kinds of fungus that cause it, it’s not reportable, and many cases probably go undiagnosed. Signs of ringworm in animals are often the same as in people, however not every animal that is infected with ringworm develops signs of infection. It has been estimated that ~90% of cats that are carrying dermatophytes do not show any signs of infection, but they can still transmit the fungus to other animals and people. (NB: this does NOT mean that ~90% of cats carry dermatophytes!)  Almost any animal can be infected by at least one dermatophyte or another – cats, dogs, rabbits, rodents… even horses and cattle!

  • Early identification of ringworm is important to reduce the risk of transmission to people and other animals. If your pet develops bald patches, particularly if they’re itchy, it should be examined by your veterinarian to determine if a fungal infection may be present.
  • If you or anyone in your household develops an area of skin that appears infected (especially if it appears as a red "ring"), keep it covered with a piece of clothing or a bandage and see your doctor.
  • Most cases of ringworm can be treated with either topical (e.g. ointments) or oral anti-fungal medication.
  • Clean your pet’s grooming supplies (e.g. brushes, combs) regularly.
  • Always wash your hands after handling your pet.

Watch for another Worms & Germs blog post about ringworm and how to clean up if you or your pet is infected, coming soon!  More information about ringworm and dermatophytes can be found on the CDC’s Dermatophytes website.