The New York Times has a nice article on hospitals that allow patient's pets to visit. This is a controversial area, with policies (when they are actually present) that range from wide-open access to complete prohibition. Like most things in life, there's a middle ground that's the most reasonable.
The positive aspects of people being allowed to have their animals come visit are pretty obvious, since people may have close bonds with their own pets and having a chance to see their pets might make a big difference to their mental state/well-being, particularly for someone who is chronically ill.
The negative aspects are less clear. We certainly know that pathogens can be transmitted from animals to people (and in the other direction too), and people in hospitals are often at higher risk of infection and complications thereof. There's a list of pathogens we worry about, but there's a serious lack of data to help determine the severity of the risk - and how to reduce it. Organized pet therapy programs are great because they are structured and there can be a lot of scrutiny and training of the pet and handler. Visits by patients' own animals are inherently less controlled, since the individual animal and handler don't undergo the same degree of assessment and training.
I get asked to review visitation guidelines frequently, and a reasonable middle-ground can usually be found. These are some snippets from the NYT article that highlight common points.
A doctor’s order allowing the family pet to visit is typically necessary...
That's a good approach, although it's not often used. This lets the doctor decide if it is reasonably safe to have the pet visit, i.e. the patient is not at a very high risk of infection. The weak link here is sometimes the doctor, because sometimes the doctor doesn't understand the risks associated with pet contact and may not identify a concern. Other times, the doctor may not understand the relatively low risk and the potential benefits, and therefore default to banning visitation without giving it much thought. I think that's less common these days but still an issue.
...as is an attestation from a veterinarian that the animal is healthy and up to date on all its shots.
The first part is great: making sure there are no health or behavioural issues with the animal that would pose an increased risk. The second part is very common but largely represents a lack of understanding of the issues. Too often, "has he had his shots?" is the main question that's asked about the animal, despite the fact that it's largely irrelevant from a zoonotic disease standpoint. Yes, we want to make sure the pet's rabies vaccination is up-to-date, but the other core vaccines are irrelevant from a human health standpoint (although they're very important for keeping the animal healthy overall).
Most institutions require that dogs — the most common visitors, by far — be groomed within a day or so of a visit and on a leash when they walk through hospital corridors.
Standard and logical policy. Grooming might help reduce the burden of bacteria, fungi and parasites on the haircoat, as well as a lot of loose fur and dander that could otherwise contaminate the hospital environment.
Cats must be taken in and out of the institution in a carrier.
Logical. Some cats do well on leashes but it's better to have a cat in a carrier when taking it through a strange area. It also helps prevent other people from coming into contact with it.
If a dog or cat wants to get up on a patient’s bed, a covering is laid down first.
Good policy, and it protects both the patient and the animal.
If an animal seems agitated or distressed when it comes into the hospital, staff members who meet the family and escort them to the patient’s room have the right to turn it away.
This has two important components. One is that the visitation is supervised, which is great. The other is that staff are given the ability to intervene in the unlikely even that there are problems.
If the patient shares a room with someone, that person must agree before a pet may visit.
This is often overlooked. Roommates might be afraid or allergic, and in those situations, visitation shouldn't happen in a shared room. There might be a way to do the visit in another room, so it doesn't necessarily preclude the visit from happening. This has to be broached in advance and in a manner that the roommate doesn't feel pressured into consenting. It's best done by having the patient's healthcare providers approach the other patient and/or the other patient's family.
There's always some risk with animal hospital visitation. That's never going to be eliminated, but a lot of common sense practices can reduce the risk to a very low level, hopefully to the point that the risk is overwhelmed by the benefits. A little structure and a lot of common sense go a long way.
It's maybe a sad statement that reading about someone whose diseased toes were gnawed off by their dog doesn't shock me anymore. It's not an everyday event but it's far from rare. An Indiana man learned about this the hard way when he woke up thinking his dog was licking his toes, when in fact, the dog had eaten them.
As is typical in cases like this, the person is a diabetic and had a foot infection, which contributed to the dog being attracted to the toes and the person not feeling the midnight snacking. Presumably, the person will be fine with some wound care and antibiotics. In fact, the dog may have just altered the manner of amputation if the toes were that severely affected. They may have been coming off one way on the other in the near future, but this is still not the desired approach.
A couple of questions come up sometimes in cases like this.
Is the man at risk of any infections from the dog?
- Certainly, there are concerns. This should be treated just like a bite since there was obviously contact between dog saliva and broken skin. Antibiotics were presumably already being used because of the toe infection, so that might have been enough, but antibiotic treatment would be needed in a situation like this given the type of exposure and the person's compromised state.
- Rabies is unlikely but it still has to be considered. This is just like a bite, so a 10 day observation period of the dog would be indicated. There's almost zero risk of rabies here, but when we're talking about rabies, "almost" isn't good enough.
Is the dog at risk of catching anything from the owner?
- This is perhaps the more likely of the two concerns. The dog was licking and eating infected tissue. Many of the bacteria that cause this type of infection can also infect dogs. The odds of the dog developing disease from this are pretty low. It's more likely the dog would become a carrier of the bacterium for a while (e.g. in its mouth, nose, or intestinal tract). If the dog is otherwise healthy, it's probably not going to suffer any consequences, but knowing what bacterium was causing the toe infection would help with that risk assessment.
While dogs amputating toes is rare, it's surprising how often I hear about people who let their dogs lick diabetic ulcers. As well, I've heard of people who have looked down and realized their dog or cat was gnawing on their toes (not amputating - at least not yet - but chewing away nonetheless). Usually, these are diabetics. Usually, nothing bad will happen. However, a dog's mouth contains many different bacteria that can cause severe illness given the right situation, and chewing on a toe of a diabetic patient in particular would fit into that "in the right situation" category.
An outbreak of equine herpesvirus type 1 (EHV-1) has resulted in implementation of a quarantine at Woodbine, a major Thoroughbred track in Toronto. This outbreak is unrelated to the recent outbreak at an Ontario Standardbred training facility.
The Ontario Racing Commission has issued the following release:
The Ontario Racing Commission (ORC) announced that there have been five confirmed reports of the neurotrophic form of EHV-1 in thoroughbreds residing in Barn 1 at Woodbine Racetrack. One horse was euthanized on June 10 after becoming recumbent with a fever. A second horse in the same barn (Barn 1) also had a fever and showed neurological signs. The second horse was transported to the Ontario Veterinary College for further evaluation and treatment.
Thoroughbred racing will continue at Woodbine. However, due to the infectious nature of this disease, the ORC has ordered the implementation of various infectious disease protocols to protect our equine athletes.
In order to determine any further spread of the disease to horses in other barns, no horses are to exit Woodbine Racetrack without ORC approval for the next 7 days (June 19). This restriction may be reviewed based on the progression of the disease.
In addition, no horse is allowed in or out of Barn 1 or Barn 3 for the next 7 days, including training. This restriction may be reviewed, based on the progression of the disease.
All horses stabled at Woodbine must have their temperatures taken and recorded visibly on the horse’s stall door for inspection. Trainers with horses that have clinical signs consistent with EHV-1 infection (including fever (101.5 F/38.5 C or above), respiratory signs (cough, nasal discharge and/or neurological signs) must report these findings to their veterinarian immediately.
Horse people who had horses at Woodbine Racetrack within the last 7 days should monitor their horses for any signs of illness. Standardbred horses are not stabled at Woodbine Racetrack. As well, the standardbred racing meet concluded at Woodbine on May 20, 2013 and moved to Mohawk Raceway on May 23. Therefore the June 15 North American Cup at Mohawk will not be impacted by these measures.
As with most outbreaks, the next few days are critical to see how far the virus has spread. Early on, you never know whether it's confined to a specific barn or group, or whether it's widely disseminated across the facility. An outbreak that just affects one barn is still a problem, but it's much easier to contain than one that's already moved beyond the initial group. Without knowing how the first horse was infected (something that's rarely identifiable), time and testing are needed to determine the extent of the spread and how hard it will be to contain it.
Several dogs at a Miami humane society were quarantined last week because of concerns (or possibly panic/over-reaction) about methicillin-resistant Staphylococcus aureus (MRSA). MRSA in dogs is a concern because it's an important cause of infection in both people and animals. However, it's an opportunist, meaning it typically doesn't cause disease when it encounters a normal, healthy person or animal. In fact, a small percentage (~1-3% probably) of the human and pet populations carry this bacterium in their nose without knowing it, and the vast majority never suffer any consequences.
It's often tough to strike the right balance when dealing with an MRSA issue. We want people to realize that it's an important cause of disease and that it needs to be taken seriously, but we also want people to keep it in perspective and not freak out.
The Miami shelter report seems to be on the "freak out" side, particularly on the part of the local media.
It's not really clear what's happening based on this fairly poor article. The shelter's Chief Medical Officer, Dr. Maureen Swan, is quoted as saying there's a routine respiratory disease cluster in the shelter, but MRSA rarely causes respiratory disease in dogs. The article then adds Dr. Swan said it was "not the highly contagious MRSA virus." I have no idea what that means, and MRSA is not a virus.
My suspicion is that they have respiratory disease caused by the typical bacterial and/or viral pathogens that are commonly found in shelter dogs, and that they isolated a methicillin-resistant staph that just happened to be hanging around in that particular dog (since such bacteria normally live in the mouth, nose and skin). It's also not really clear whether this is MRSA. The article says MRSA, but the first thing I ask when I get an advice call about MRSA is "what staph species does the report say was isolated?". Most often, it's Staphylococcus pseudintermedius or another staph. These bugs can still be relevant, but they don't carry the same human health risk as MRSA, so it's important to know exactly what's been found.
Finding MR staph, including MRSA, isn't unheard of in a shelter. It's just one of many reasons that good general infection control practices are needed in these facilities. When MRSA is found, taking some extra precautions is reasonable because of the potential for disease and transmission to people, but too often people panic. It's understandable based on concern about MRSA and the scary stories people can find with a quick Google search. Not uncommonly, there's a combination of an short-term overly aggressive response while at the same time failing to improve basic infection control practices, which are the most important.
More information about MRSA can be found on the Worms & Germs Resources - Pets page.
The latest edition of the University of Guelph Animal Health Laboratory's newsletter contains an interesting report about 4 horses that died over the past few years from what was suspected to be contaminated intravenous fluid solutions. These cases were dead horses that were submitted for post-mortem examination from three different farms, so if anything, this could be an underestimation of the problem.
The first two horses were from the same farm. They were young Thoroughbreds that were routinely treated with intravenous electrolytes, vitamins and minerals (whether by the trainer or veterinarian is unknown). The first horse was found with its head hanging low after treatment. It later developed seizures and died. The second horse showed similar signs. The bacterium Klebsiella pneumoniae was isolated from a few different tissues of the first horse, as well as one of the "jugs" used to administer the fluids. The second horse had the same general lesions as the first, but Klebsiella wasn't isolated; however, this may have been because the body wasn't in great shape by the time it was submitted to the lab, and various other bacteria had overgrown the Klebsiella, making it difficult to isolate.
Another case was a young Standardbred that died after receiving intravenous fluids with vitamins, and a glyceryl guaiacolate jug. It had signs of bloodstream infection (septicemia) and Klebsiella oxytoca was isolated from multiple organs. Various bacteria were isolated from remnants of fluid in treatment bottles.
The final case was a five-year-old Standardbred that died after receiving a home-mixed vitamin jug. It had lesions similar to the other horses and consistent with a bloodstream infection. Klebsiella oxytoca was isolated from multiple organs.
Contamination of multidose drug vials or fluid solutions can occur if bacteria are inoculated into the bottle with a needle when a dose if withdrawn. We've shown this happens with multidose vials in a hospital situation, and of the farm it's even more likely to occur because it's a dirtier environment and, in the case of farm personnel, individuals have less experience with sterile technique. Fluid solutions can be contaminated in the same manner or when something is added to the fluids (e.g. vitamins). Contamination of reused fluid administration sets (i.e. fluid jugs/bags and the IV tubing) is quite likely, and that's why use of sterlie, single-use administration sets is recommended. Adverse events from a little bit of contamination are uncommon, but as shown here, they can happen and they can be severe. There's no information about what contributed to the contamination in these cases, but it's almost certain that poor infection control practices were at the root of the problem. Trying to save money by skimping on sterilization, reusing items without proper care, and using poor hygiene practices in general can end up costing much more.
Darwin's back in the news. He’s a young macaque who is often called the "Ikea Monkey" since he was found wandering around a Toronto Ikea parking lot one day last winter in a designer winter coat. He was seized because of a Toronto bylaw prohibiting monkeys as pets, and transferred to a local primate sanctuary. His owner, Yasmin Nakhuda, has been waging a high profile battle to get him back. There are numerous Facebook pages dedicated to freeing Darwin, and she apparently sent him a birthday greeting (perhaps not realizing it's unlikely that he had internet access at the sanctuary... or can read).
Anyway, Ms. Nakhuda is suing for custody and the trial is currently underway. Needless to say there's a lot of drama in the courtroom as Ms. Nakhuda tries to regain custody of the animal she calls her "son." Much of the trial has centred around issues of property, which I guess makes sense since that’s the main legal avenue.
However, what’s not been mentioned are the greater concerns, namely does Darwin pose a risk to the public and does Ms. Nakhuda pose a risk to Darwin? I think the answer to part 1 is certainly yes, and the answer to part 2 is maybe.
The first question (does Darwin pose a risk to the public) is easy. There are a variety of issues with keeping non-human primates as pets. They can be destructive, they are surprisingly strong for their size, and macaques are notorious for being aggressive, so the risk of trauma alone is a major issue. Disease is another concern, and the big problem in this case is herpes B virus. This virus can be found in most healthy captive macaques and can cause fatal infection in people. The fact that it’s been reported that Darwin was prone to biting makes me cringe, since that’s a huge risk for herpes B transmission. Among the trial testimony was an email Ms. Nakhuda sent to a US primate trainer in November documenting her struggles. Among the problems was aggression that Darwin had towards her son and co-workers.
It’s bad enough that she’s exposing herself and her family (including her human chldren) to Darwin. Exposing people with whom she works (and perhaps people who work for her, and would have a hard time raising any concerns they had) is completely inappropriate, as is taking Darwin out in public (apparently "everywhere," including the gym, grocery store, and obviously Ikea). Ms. Nakhuda either doesn’t understand the issues or doesn’t care. Either way, it’s not good.
I don't doubt that Ms. Nakhuda cares for Darwin. However, as the primate sanctuary lawyer Kevin Toyne said "This is not about who loves Darwin the most." For me, it should be about protecting the best interests of the public and Darwin, neither of which would result in him being returned to his previous owner.
An abstract for the upcoming CSTE (Council of State and Territorial Epidemiologists) conference in California describes a rare but concerning case of Brucella canis infection in a child. All I have to go by is the abstract (since the meeting hasn’t happened yet and I won’t be there anyway), but it provides an interesting outline.
Brucella canis is a bacterium that is (not surprisingly, given the name) associated with dogs. It’s present in dogs internationally, with higher rates of infection in strays and shelter dogs. It can cause a variety of problems in dogs, most often abortion, stillbirth and birth of weak puppies, but also things like reproductive failure and genital inflammation in males, and diskospondylitis (a kind of back problem). After a dog gets infected, the bacterium can localize to genital tissues, where it tends to hang out, resulting in intermittent shedding of B. canis in urine, vaginal discharge, fetal fluids, semen and, to a lesser extent, some other tissues. Humans can then be exposed via contact with these fluids. The main risk to humans comes from handling breeding dogs, particularly female dogs that have aborted puppies. However, people seem to be relatively resistant to B. canis infection, and there are actually only a small number of reports of human infections with this bacterium.
The risk to average pet owners is very low, but as this report shows, low doesn’t mean zero. This abstract deals with an infection in a 3-year-old child from New York city. The family had acquired a Yorkshire terrier puppy from a local store in March 2012. As is expected, there was close contact between the child and the puppy.
Near the end of April, the child was taken to an emergency room because of fever and difficulty breathing. Bacterial infection wasn’t the main suspect and he was discharged without antibiotics (presumably having improved from how he was at the time of admission). However, a blood culture was collected and it came back positive for Brucella canis. While the boy had been doing well, he was treated with 45 days of antibiotics to try to make sure the bacterium was eliminated, since it can cause chronic problems.
In a step that’s too often overlooked in zoonotic disease occurrences, there was an investigation of the source. That’s not surprising since this is a rare and concerning bacterium, and it’s pretty clear that pet contact tracing is required. The puppy was healthy but the bacterium was isolated from its blood. Because of the test result, the puppy was euthanized. (There’s no mention of whether this was at the owner’s request or based on the recommendation of public health personnel.)
The source of the puppy was a major concern, since it’s important to make sure that there aren’t other infected puppies around. The puppy came from a "commercial breeding facility" in Iowa - yet another instance of the potential for widespread national and international distribution of pathogens from large commercial pet operations. The facility was quarantined but there’s no more information in the abstract about whether other positive animals were found, whether infected puppies may have been sent elsewhere in the country, and what measures were taken to correct the problem.
A littermate of the New York puppy was sold by the same store. It also tested positive for B. canis and was treated.
This is a rare incident, but it highlights some points for me:
- Large commercial breeding facilities for dogs are unnecessary and create increased risk of disease in animals and by extension people. Yes, this could occur with a small private breeder, but the more animals, the more risk of infectious disease, and the larger the facility, the larger the potential impact should a disease issue develop.
- Proper counseling of people whose pets are diagnosed with a zoonotic pathogen is needed. I don’t know the story at all about why the first puppy was euthanized, but it might have been avoidable. What to do with animals that are healthy but shedding potentially concerning pathogens is a tough area to address. That’s particularly true for a bug like B. canis, since it can be hard to eliminate.
- Good communication is needed between the medical field, public health, veterinary medicine and the public. It’s hard to say how smoothly this investigation actually went, but it shows a good response to a rare but potentially serious problem.
- People that sell animals need to keep accurate contact information from purchasers. It’s good to see that they were able to track down the owners of the original puppy's infected littermate. Contact tracing is important with infectious diseases and it can be exceedingly difficult at times.
- There’s an inherent risk in pet ownership. We know that and have to accept it. The child was high risk because of his age. That doesn’t mean we don’t let kids have pets, but we have to understand the risk and use some basic hygiene practices to reduce that risk. Would it have had any impact on this case? Who knows, but it never hurts to improve.
I’ve written about the African dwarf frog and Salmonella issue before, but it’s worth a recap since an overview of the 2008-2011 outbreak was recently published in the journal Pediatrics (Mettee Zarecki et al 2013). The fact that reptiles and amphibians can carry Salmonella is nothing new, nor is the fact that outbreaks of disease can occur in people who have contact with them. However, the scale of outbreaks associated with pets can be impressive.
Here are some highlights from the paper:
- Between January 1, 2008 and December 31, 2011, 376 people were diagnosed with salmonellosis caused by the outbreak strain, a type of Salmonella Typhimurium.
- As is common in pet-associated outbreaks, kids bore the brunt of this one. The mean age of infected individuals was 5 years, and 69% were children under the age of 10.
- Severe disease wasn’t uncommon - 29% of people were hospitalized, half of those being kids less than 5 years of age. Fortunately, no one died.
- During a preliminary study, when they compared people who got sick with a group of healthy controls, they found that people who reported exposure to any aquatic pet were almost 5 times as likely to have salmonellosis. When that was narrowed down to exposure to just frogs, the risk went up to 12.4 times higher than healthy controls.
- When they looked at people who were sick and reported exposure to frogs, only 27% reported having touched a frog, with 46% reporting having fed a frog, 59% having had contact with a frog’s habitat and 60% having had contact with water from a frog’s habitat. Twenty-three percent (23%) reported cleaning the frog’s habitat in the kitchen sink, and 35% in the bathroom sink. This tells us some very important information. It tells us that direct contact with frogs or their environment is a high risk behaviour. However, direct contact isn’t required to get sick. While the frog may stay in its habitat, Salmonella may not. Cleaning habitats in kitchen or bathroom sinks is a high risk activity, because it can result in contamination of common human-touch surfaces and items that go into peoples’ mouths (e.g. toothbrushes, cups).
- Often, disease occurred not long after a new frog was obtained. The median time from purchase of a frog to disease was 30 days (range 5-2310 days).
- Only 17% of people interviewed reported knowing that frogs can carry Salmonella. Over twice as many knew there was a risk from reptiles. This shows there needs to be more education of people who buy animals such as frogs. Pet stores should be required to provide some basic public health information. Pet owners should also take initiative and research potential new pets, including how to care for them and how to reduce the risk of zoonotic infection.
- The outbreak Salmonella strain was found in the environment of some patient homes (not surprisingly), an African dwarf frog vendor (potential source of infection), a large-scale African dwarf frog distributor (a great way to spread an outbreak across the continent) and a daycare centre (that never should have had an amphibian in the first place!).
- One breeding facility in California was the likely source. With centralized, large-scale breeding and warehouse-style distribution of pets (of various species, not just frogs), we’re seeing more large-scale outbreaks like this.
More information about African dwarf frogs can be found on the Worms & Germs Resources - Pets page.
Studies that look at risk factors can be pretty variable in terms of what they tell you, the impact they have and how accurate they are.
Some findings are pretty logical, clear and indicate something that should be done.
- Smoking is a risk factor for [insert many diseases here], so to reduce the risk of [whatever disease], stop smoking.
Others make sense but don’t necessarily lend themselves to an effective intervention.
- Being male is a risk factor for cardiovascular disease... not much I can do about that.
Sometimes, you have to remember that a risk factor for one thing doesn’t provide a clear answer when a broader context is considered.
- Moderate consumption of red wine can reduce the risk of various conditions, but alcohol consumption can also increase the risk of other conditions.
Sometimes, how the study is designed and performed can really affect the results.
- If I did a large study of the general population in Guelph, I could presumably show that going to a hospital greatly increases your risk of death. Does that mean you shouldn’t go to the hospital? No, because I could presumably also show that if you have chest pain and go to a hospital, you’re more likely to live. Knowing the study population and what question is really being asked are critical.
Sometimes, something that’s found to be a risk factor isn’t really the risk factor, but it’s associated with something else that is.
Sometimes, something can be "statistically significant," but of limited consequence.
- If doing something increases the risk significantly, but only by 0.0001%, does that mean anything?
Why do I write this? Because these are some of the things that we have to think about when assessing risk factor studies. While one Toronto radio station loves to give 10 second snippets on some new risk factor medical study, you can’t determine much about the study itself from a sound-bite (or internet post). You need to think about the details regarding how the study was done. Nevertheless, risk factor studies can provide useful information, but consider the results carefully, whether they are relevant, whether they indicate changes need to be made or whether they indicate that we need to look at the issue further.
The first study compared dogs from northern California that had or didn’t have leptospirosis. They found a few things:
- There were differences in geographic distribution of the lepto cases and controls. That makes sense since we know lepto varies regionally, but living in different areas might also be associated with different behaviours and contacts (e.g. wildlife contacts).
- There was a temporal cluster, with more cases occurring between May 2003 and May 2004, compared to the rest of the 2001-2010 study period. That makes sense too since we see variation in cases within and between years.
- These results don’t change anything, but are an indication of what work needs to be done next. Looking at why things vary geographically and temporally might be important for figuring out how to reduce the risk of disease. It also indicates regions where more efforts to educate pet owners (and veterinarians) are indicated, and where vaccination is more important.
The second study looked at dogs from Kansas and Nebraska, with and without leptospirosis. They also found a few risk factors.
- Lepto was more common in houses lacking complete plumbing facilities. Presumably, this is a proxy for something else. Poor plumbing doesn’t likely result in lepto in dogs. Rather, it presumably means that a dog living in a house with poor plumbing has some other factor that increases its risk. For example, incomplete plumbing may be more likely in lower socioeconomic (i.e. lower income) households, which might then correspond to other more direct risk factors for the dog (e.g. poorer nutrition, less veterinary care). It could also be that houses lacking complete plumbing tend to be in a different area where there’s more exposure to wildlife reservoirs. A couple of other indicators of poverty status were also significant, highlighting the potential impact of owner poverty on pet health.
- Dogs that lived within 2500 m of a university or college, or a park, were also at increased risk. The park risk factor makes sense since they could be exposed to sites infected by wildlife reservoirs (e.g. raccoons). Living close to a university or college is tougher to figure out. Maybe it’s associated with economy, as students are typically at lower income levels. Maybe it’s because colleges and universities usually have lots of green space that might harbor wildlife.
So, these studies tell us some new information, reinforce some previous knowledge (or perceptions) and raise some new questions that we need to answer. By themselves, they won’t result in major changes in how we try to prevent lepto in dogs, but little steps is typically how science progresses.
Horse show season is upon us, and with it comes the questions from concerned horse owners who want to protect their animals from the infectious diseases they may encounter at these events. In this case, the specific question is:
What protocol would go into place if a horse with a highly contagious disease such as EHV-1 were to be found at a competition in Canada?
The short answer (to the surprise of many) is that there is no pre-established nation-wide protocol for most equine disease outbreaks. Every outbreak is managed differently, based on the disease, the types of horses, where exposure might have occurred and a range of other factors. Typically, a disease like EHV isn't going to be noted during the show, since it takes some time for illness to develop after exposure. Therefore, the response is more of an investigation of what happened at the show, why and how it can be prevented in the future, and of course trying to prevent further transmission in the community (e.g. identifying exposed horses, communicating with people who have been to the show with recommendations to quarantine and test exposed horses and potentially all horses, surveillance for ongoing transmission from horses that have left the show).
With horses, there's no regulatory body with a mandate to oversee (and fund) this type of investigation unless it's a federally reportable disease like rabies (and even then, assistance may not be forthcoming). Some provinces have more authority and interest (e.g. the Animal Health Act in Ontario gives the province a mandate and powers to intervene) but often investigation is not a priority for regulatory bodies and it's left to whoever is around and interested. There are some good outbreak management guidelines from different institutions or groups (e.g. the ACVIM consensus statements on EHV and strangles) but there is no standard approach. Because testing costs are placed on the owners, responses can be quite variable since getting people to test when indicated can be a challenge. Additionally, getting people to follow quarantine recommendations is a challenge because of inability to effectively quarantine on their farm or unwillingness to do so (usually more the latter). So, each outbreak ends up being managed quite differently.
In general, the key points to outbreak investigation and management are:
- Identification of a problem
- Diagnosis of the problem
- Communication to let people know what's happening
- Identify potentially exposed and infected horses
- Quarantine, if appropriate (usually some form of quarantine is indicated, but not necessarily for all diseases)
- Develop testing recommendations
- Develop and communicate a plan to maximize compliance with quarantine and testing
- Create a way to centralize data collection and communications, so that a clear picture of what is happening is obtained
- Keep people in the loop as the investigation ensues to maximize compliance and decrease loss of compliance because of boredom or fatigue with the recommendations