Maureen Anderson
Maureen Anderson is currently a post-doctoral fellow in the Department of Pathobiology at the University of Guelph. She grew up in Montreal, Quebec. In 1998 she moved to Guelph, Ontario where she completed her veterinary degree in 2003. Following a year and a half in mixed animal private practice in Listowel, Ontario, she returned to the University of Guelph for graduate studies in infectious disease and a residency in Large Animal Internal Medicine. She completed her thesis on methicillin-resistant Staphylococcus aureus (MRSA) in horses in December 2007, and became board certified with the American College of Veterinary Internal Medicine (ACVIM) in the spring of 2008. She has two cats named Bonnie and Clyde.
Risks of Raw - More evidence
A study by Erin Leonard of the University of Guelph and others, that has just been published in the journal Zoonoses and Public Health, once again points to the increased risk of Salmonella shedding associated with feeding raw diets to dogs. The study looked at 138 dogs from 84 households in Ontario. One-quarter of households (21/84, 25%) had at least one dog (32/138, 23.2%) that was shedding Salmonella at one time, which is considerably higher than the 1-4% of pet dogs that are typically expected to be shedding this zoonotic pathogen. Only 4 of the 32 positive dogs had any history of diarrhea in the last month, so the vast majority of these dogs had no signs that they were shedding Salmonella. Here were the study's main findings:
1. Consuming a commercial or homemade raw diet, a homemade cooked diet, or raw meat and eggs, increases a pet dog’s risk of carrying Salmonella.
Raw is raw, and by now we're hoping that people are getting the message that raw is contaminated, whether we're talking about a commercial or homemade raw diet, or feeding any raw animal products (e.g. meat, eggs). The fact that homemade cooked diets also made the list could be explained by the fact that in order to make such a diet, owners still need to start with the raw ingredients. Handling and cooking raw meat and animal products for your pet should be done with the same precautions as handling and cooking raw meat for yourself or your family. If these homemade diets were not cooked as thoroughly as they should have been, or if there was contamination of the dog's dishes with raw product, that could explain the association with Salmonella shedding. Although traditional commercial diets can also be contaminated with pathogens (usually after processing), the risk with these is much lower.
2. Testing multiple consecutive whole fecal samples greatly improves Salmonella recovery in dogs.
This is no great surprise either. Dogs (and many other species) shed Salmonella intermittently, so not every fecal sample from a Salmonella-positive dog is going to yield Salmonella on culture. The authors tested five daily fecal samples from each dog. Based on this study, the sensitivity of testing a single fecal sample in a dog (i.e. the likelihood that a Salmonella-positive dog will test positive on one fecal sample) was only 35.5%. That means almost two-thirds of positive dogs will be missed if they're only tested once. The take-home message on this point is that in order to find Salmonella in a healthy pet dog, multiple samples should be tested.
3. Having multiple dogs in a household, using probiotics and contact with livestock are important potential risk factors that need to be investigated further.
These were factors that were flagged by the authors for future investigation, because at first they seemed to be associated with Salmonella shedding in the dogs, but when the feeding of raw diets was taken into account the associations were no longer significant. A larger study, or one using a different design, will be needed to help tease apart the potential effects of these factors from feeding practices.
The bottom line: Feeding raw is risky business. Some people swear by the benefits of raw diets, but the objective evidence is lacking. There is clear evidence of the risks. In my mind, the potential up-side simply cannot outweigh the well-established down-side of feeding raw diets to pets.
Baylisascaris in Winnipeg
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There was another paper published in the August issue of the Canadian Veterinary Journal about Baylisascaris procyonis (roundworms) in raccoons, this time in Winnipeg, Manitoba (Sexsmith et al 2009). The study was actually undertaken after infection with B. procyonis larvae was identifed as the cause of death of several animals in the collection at the Assiniboine Park Zoo in Winnipeg.
The researchers collected feces from 52 active raccoon latrines around the city and from 114 "nuisance" raccoons that were caught, euthanised and submitted for necropsy to the local lab. Interestingly, the vast majority of latrines and nuissance raccoons were found close to the two major rivers that run through Winnipeg. Half (50%) of all the latrines were positive for roundworm eggs on at least one sample (out of a possible 3). Among the necropsied raccoons, 61/114 (53.5%) were positive for roundworms. Adult raccoons were almost four times as likely to carry roundworms than juveniles (which is in contrast to a previous study that found juveniles more likely to be infected), and bigger raccoons (over 2.75 kg) were more than seven times as likely to carry roundworms compared to smaller animals. Although there are regions where the prevalence of B. procyonis s reported to be very low, Winnipeg, like many other regions of North America, has joined the ranks of those where the prevalence is high and the public needs to be aware of the associated risks.
The most severe zoonotic disease caused by B. procyonis is called neural larval migrans (NLM), which results from migration of parasite larvae through the central nervous system (i.e. brain). Two of the reasons this is much more of a concern with raccoon roundworms (Baylisascaris) compared to dog and cat roundworms (Toxocara) are:
1) A massive number of parasite eggs are passed in the feces of infected raccoons (which typically have a very high burden of adult worms). Coupled with the fact that the eggs are further concentrated in areas where many raccoons defecate (latrines), this can lead to heavy exposure of people (or animals) who come in contact with the soil in these areas, which greatly increases the risk of infection.
2) The larvae of B. procyonis are very active migrators, and they get bigger as they migrate through tissues - much bigger than Toxocara larvae ever get, which means they also tend to cause a lot more damage before they're finally (if ever) trapped or killed by the body's immune response.
Natural infection of dogs living in the same areas as raccoons has been found - it's not common, but it appears to occur frequently enough to warrant noting. Dogs and cats can also be infected by their own species of roundworms, which will also result in parasite eggs being shed in the feces. It's important to have your veterinarian perform a fecal examination for your pet on a regular basis so any parasite infestations (roundworm or other) can be treated.
Dogs and cats may also be susceptible to larval migrans in the same manner as people (and the animals at the zoo in Winnipeg) if they are exposed to high numbers of infectious eggs. Remember that roundworm eggs must be swallowed in order for infection of any kind to occur, so good hand hygiene and avoiding soil contamination of food are key to preventing transmission. Also, do not allow your pet to dig or play in an area where raccoons defecate (preventing direct contact between your dog and raccoons should go without saying!). And of course, feces of any kind (and from any species) should be treated as infectious material, and handled with appropriate precautions.
More information about Baylisascaris and raccoon latrines is available in our archives.
Things not to do for Thanksgiving
I heard this on the radio yesterday morning, I kid you not: Butterball has a "Turkey Talk" toll-free helpline, which naturally gets busy around turkey holidays like Thanksgiving and Christmas. Like many helplines, they get stories of every kind, and this year apparently one person called in and asked if it was alright that she thawed her frozen turkey in the bathtub - while her kids were in it taking a bath!
Anyone who has read anything about food safety hopefully knows that raw meat can potentially be (and usually is) contaminated with many different pathogens - that's the biggest reason why observing proper cooking times and temperatures is so important. Raw poultry in particular should basically be treated like it's contaminated with Salmonella and/or Campylobacter until proven otherwise. You can just imagine the field day that these bacteria could have in a nice warm, wet bathtub - it's just the way they like it, and it's exactly what we try to avoid in the kitchen, where food is ideally kept either nice and cold or nice and hot in order to prevent (or at least minimize) bacterial growth. Then of all things to put young children in this veritable cesspool of bacteria - turkey and all - it's just a gastrointestinal disaster waiting to happen. You also needs to consider what the turkey could become contaminated with sitting in bathwater. Even children who don't have diarrhea can be shedding intestinal pathogens - human pathogens which are obviously transmissible to other people. If you really cooked that bird well (maybe deep-fried it) I suppose that should ultimatley eliminate any surface contamination anyway, but I don't think I'd be able to get past the "ick" factor. Don't throw the baby out with the bathwater, but of there's a turkey in there (as far as I'm concerned) that can go.
I realize this is primarily a food safety issue, but it made me think about what else this person (or others) may put in a bathtub. In previous posts in which we've talked about reptiles kept as pets (all of which should be treated as Salmonella carriers), we've mentioned that ideally (if they need a bath) they should be bathed in their own designated container (like a big rubbermaid) and not in the bathtub. If there is no other option and the bathtub must be used, it should be thoroughly cleaned and properly disinfected (keeping contact-time with the disinfectant in mind) before it is used again by a person (especially children).
Ideally the same precautions should be taken if you bathe a dog in the bathtub, but the risks are not as high as with reptiles (unless the dog is very dirty, has skin lesions, or has (or recently had) diarrhea). We've talked about the limited risks of allowing dogs in backyard swimming pools (but of course there is even less chlorine in bath water). I hope no one ever bathes their dog with their kids - we could debate the risks, which likely aren't high anyway, but in the end the risk is simply unnecessary. The pool is one thing, but there's no reason for a dog to be in the tub at the same time as the kids (and really, how clean are the kids going to get with a dirty dog in the tub?). If you're trying to save water you can always throw the dog in after the kids are out.
If you're attempting to bathe a cat in the tub... well, based on most feline behaviour I'd say your primary risks are bites and scratches more than enteric bacteria and parasites. Proceed at your own risk!
A happy (and hopefully healthy) American Thanksgiving to all of our US readers!
Antibiotic Awareness Day
European Antibiotic Awareness Day is an initiative of the European Centre for Disease Prevention and Control. This year it falls on November 18. The aim of the Day is to provide an annual opportunity for raising awareness about the threat to public health of antibiotic resistance and how to use antibiotics responsibly.
Responsible use of antibiotics can help stop resistant bacteria from developing and help keep antibiotics effective for the use of future generations. Successful national public awareness campaigns are already resulting in more rational use of antibiotics and a reduction in levels of antibiotic resistance in Europe.
Responsible use of antibiotics includes use in people and in animals. Here are some of the things you can do to help with regard to antibiotic use in your pets:
- Only give your pet antibiotics if directed to do so by your veterinarian.
- Make sure your pet gets the full dose of medication at the correct time(s) of day. If you are having problems getting your pet to swallow pills or take medication, contact your veterinarian as soon as possible. Your veterinarian may be able to give you advice on some "tricks" for getting your pet to take the medication, or sometimes the medication can be provided in a different form (e.g. a liquid instead of a pill).
- Always ensure your pet finishes the entire prescription. There should be no leftover pills or medication. Do not stop giving your pet the antibiotics just because it looks/acts like its feeling better. This is a common mistake that can have disasterous consequences! You should NEVER "save a few pills for the next time."
- Never give your pet antibiotics that were prescribed for you or any other person, whether they are expired or not.
Swine flu has gone to the birds
Just when all those turkeys that managed to survive Thanksgiving weekend thought their troubles were over, there's new issue: H1N1 influenza (formerly known as swine flu) has been found in an Ontario turkey flock. The H1N1 virus was first reported in birds in Chile in late August.
This is not a reason to panic. No one can get the flu from eating a properly-cooked Thanksgiving turkey (nor from any other type of properly-cooked turkey). The producer has voluntarily (and very responsibly) quarantined the affected flock, and no birds or eggs have left the facility. There is no risk to the food chain.
Pigs can be infected by human, pig and bird flu viruses, and multiple infections can result in viruses trading genes and producing new viruses that can infect more species. So it's not too surprising that H1N1can infect people, pigs and now birds as well. This incident serves as an important reminder that we need to remain diligent about infection control and hygiene, even around animals. It's highly unlikely that these turkeys had contact with infected pigs - most likely the virus was spread to this flock by a person. Poultry producers may therefore need to consider getting vaccinated for H1N1 flu not only to protect themselves, but also their flocks, and anyone who may have the flu should definitely stay off these farms. Hopefully the virus does not become established in wild bird populations (like H5N1 has in some areas), as this would make it much harder to control.
Recommendations for avoiding the flu (H1N1 or other) remain the same:
- Wash your hands and/or use alcohol-based hand sanitizer
- Sneeze into your elbow
- Disinfect commonly touched surfaces
- Stay home if you are sick
- Get vaccinated!
Canine lepto: It's that time of year again
The latest newsletter from the University of Guelph's Animal Health Laboratory contains a brief update on the percentage of positive MAT tests for canine leptospirosis that the lab has seen in the first half of 2009. Approximately 30% of the tests have been positive, which is up from the previous two years. However, the prime time for lepto cases (and therefore typically also lepto testing) is just starting: the cool damp fall weather provides a great environment for lepto bacteria to survive outdoors for the next several weeks.
Prevention of lepto in dogs, as with most diseases, is preferred to trying to treat sick animals. The best way to avoid the bacterium is to keep your dog out of areas where infected wildlife may urinate frequently, particularly out in the bush. But of course, skunks and raccoons can be found as close as the backyard as well, so even in the city the risk isn't zero.
If your dog does frequently go into the bush and is at increased risk for leptospirosis, hopefully you've already discussed vaccination with your veterinarian. While the vaccine available doesn't protect against all types of lepto, it does help protect against the most common ones - in Ontario, these are believed to be the lepto serovars grippotyphosa and pomona. We also received the following question from a reader the other day:
"Should a dog who has shown positive for early stages of kidney disease be vaccinated against leptospirosis? Can the vaccine accelerate the illness to acute renal failure?"
I can see where the question comes from, but the simple answer to the second part of the question is no. Although the infection can certainly affect the animal's renal function (and can push even healthy dogs into renal failure if it is severe), the vaccine works on the dog's immune system and does not affect the kidneys directly. The answer to the first part of the question is, of course, much more complicated, and depends on many other factors including the dog's overall health status, lifestyle and other risk factors, and vaccination history. The decision about whether or not to vaccinate your dog should be discussed on an individual basis with your veterinarian.
More information about leptospirosis is available on the Worms & Germs Resources page and in our archives.
Image: Scanning electron micrograph of Leptospira sp. bacteria (source: CDC Public Health Image Library ID#138))
Cooperating on Q Fever
Another surge in the number of cases of Q fever in people in the Netherlands has been reported. Prior to 2007, the average number of cases of Q fever per year in the country was only 15. In 2007 there were 192 cases, and last year there were 958 cases, making this the largest community outbreak of Q fever ever reported. At the beginning of May 2009, another jump in the number of cases - over 200 - was reported by the dutch newspaper de Volkskrant.
Q fever is caused by a highly infectious organism called Coxiella burnetii. The organism can be carried by many different animals, but particular sheep and goats, and sometimes cattle. Most of the time it does not cause a problem in these species, but it has been linked to abortions and abortion storms (i.e. when many animals in the herd abort in a short period of time). It can be shed in manure, urine and milk, but the largest numbers of organisms are found in birth fluids and tissues (e.g. aborted fetuses, placentae). When the tissues and fluid dry out, the organism can be stirred up into the air over short distances in dust. Humans are highly susceptible to C. burnetii, and inhaling even a single organism can cause infection. Most of the time people who get sick have signs very similar to the flu, but severe pneumonia and liver disease can develop in a small number of cases.
A definitive link between sheep and goats and the Q fever outbreak in people in the Netherlands has not yet been established, but it is highly suspected that many of the cases are associated with infected goats (and some sheep). In the last two years numerous outbreaks of Q fever have been reported on dairy goat farms and one dairy sheep farm in the Netherlands. This has lead to a cooperative arrangement between the Dutch agricultural ministry and the Dutch public health ministry - these two goverment branches have come together to help cover the costs of vaccinating sheep and goat herds in the country, in order to help stem the tide of disease and ultimately prevent more human cases. This is a great example of the "one medicine" concept, whereby groups on both the human health and agricultural/animal health sides are working together on this problem.
Manditory vacciation is now required for sheep and goats on larger farms in the hardest-hit areas, as well as any farms reporting any cases of Q fever since 2005, and any sheep or goats that have a "public function" (e.g. petting zoo animals or occupational therapy farms). It is very important that this last group is included under the manditory vaccination, as these animals have a large amount of contact with people. Steps have also been taken to improve hygiene, restrict spreading manure from sheep and goats, restrict visitors to infected farms, and to make abortion storms on sheep and goat farms reportable, so they can be investigated for Q fever. It will be interesting to see how effective these measures are at controling the outbreak in 2009.
More information on Q fever can be found in our archives.
Oprah's Parvo Pups
The latest issue of Oprah's magazine "O" features the icon talking about her recent puppy dog adoption drama involving canine parvovirus. It just goes to show that even the pets of the biggest celebrities in the world are not beyond the reach of common microscopic infectious pathogens.
A couple of months back, Oprah adopted two cocker spaniel puppies from a shelter in Chicago. Unfortunately, within two weeks they both came down with parvovirus infection and had to be hospitalized. I'm sure both dogs received top-of-the-line care with no expense spared, but even so one of the puppies died. The other puppy came very close to dying as well, but happily she apparently has now recovered completely and is doing just fine (or quite likely better than fine, considering who her new owner is!).
Oprah also mentioned how one of her other dogs, Solomon, also suffered from a parvo infection years ago, but that dog was over a year old when he became ill. It's actually quite unusual for any dog to get parvo beyond one year of age - most adult dogs are not affected by the virus, unless perhaps their immune system is compromised for some reason.
These stories bring up a few interesting points to ponder:
It's great to adopt an animal from a shelter and give a homeless animal a home. It is an act of great kindness that I don't want to take anything away from in the least. However, it's important to realize that you never know what shelter dogs may be carrying, nor how well vaccinated they are.
- Even if the animals are vaccinated once at the shelter, the protective effect may be less than ideal if a properly timed vaccination series is not completed.
- In this case the pups may have been exposed to parvo after leaving the shelter, but they could have just as easily been exposed at the shelter, which begs the question of what else might they have been carrying? Bacterial pathogens such as Salmonella and Campylobacter are also particularly common in young dogs and cats (even healthy ones), and these are potentially zoonotic agents.
Young animals, particularly from shelters, are higher risk in terms of the infectious diseases they can carry and transmit. That doesn't mean they shouldn't be adopted, but it does mean taking some extra precautions for the first several weeks they're in their new home. These include being very diligent about controlling stool contamination of any kind (which can be easier said than done during the house-training phase), preventing contact with high-risk individuals (e.g. young children, the elderly, anyone with a weakened immune system) and lots of handwashing on the part of everyone involved with the puppy (or kitten!).
Parvo is a very serious disease in puppies, yet people sometimes become a little complacent about vaccinating for parvo and other puppyhood diseases. Remember, though, that the reason parvo has become so much less common than it used to be is largely because of widespread and effective vaccination. I have to wonder about how well vaccinated Oprah's dog Solomon was to get the disease at the age he did, but there could easily be other factors involved as well. The virus is still out there, and if we become lax in our infection control practices - including decreasing exposure of puppies to the stool of other dogs, as well as vaccination - it's waiting in the wings for its opportunity to move in. Even with the very best care the infection can still be fatal.
It's also relevant to note that, as demonstrated by Solomon's case, just because parvo is very uncommon in adult dogs doesn't mean it's impossible for them to get it. It's important to always remain diligent.
Parvoviruses are quite species specific, so thankfully people cannot get parvovirus from dogs, but remember that puppies can get diarrhea from pathogens like Salmonella, which can be transmitted to people. There is also a human parvovirus which is the cause of Fifth disease. Just like the dog virus cannot infect people, the human virus cannot infect dogs.
Image source: http://omg.yahoo.com
Rhodococcus equi in horses and people
Rhodococcus equi is a very well recognized pathogen in horses – it is a common cause of pneumonia in foals between the ages of 1-6 months, and infection is also sometimes associated with other problems such as diarrhea, swollen joints and abscesses in other parts of the body. The infection can be very difficult to treat because the bacteria are able to live inside white blood cells, which helps protect them from the body’s immune system, and because they often cause abscesses to form, which are difficult for antibiotics to penetrate. Rhodococcus equi infection in foals has been studied extensively, but there’s still a lot we don’t know how the body defends itself against this organism. These are a few things we do know:
- Almost all foals are exposed to R. equi as neonates, but most of them never develop signs of infection.
- Giving newborn foals hyperimmune plasma (plasma with extra antibodies against R. equi) may have some beneficial effects on farms where the infection is a recurrent problem, but this practice is still controversial.
- Adult horses are essentially immune to the infection.
- In almost all cases if clinical disease in foals, the R. equi strain involved carries a special gene called vapA.
- Mortality rates in foals vary considerably from 0% to 30%.
- So far, efforts to develop a vaccine to help protect foals have been unsuccessful, but research in this area is ongoing.
People can also be infected with R. equi, and as in foals, pyogranulomatous pneumonia (infection of the lungs which results in the formation of many abscesses) is one of the most common conditions caused by this organism. However, there are a few important differences between infection in people and infection in horses:
- 85% to 90% of people with R. equi infection are immunocompromised, meaning their immune system is weakened or suppressed for some reason, e.g. HIV infection, or immunosuppressive drugs taken by organ transplant or cancer patients.
- Among people infected with R. equi who have normal immune systems (i.e. immunocompetent), about half of the infections are localized, meaning they only affect one small part of the body. Many of these are associated with wound infections.
- Only 20% to 25% of the R. equi isolates in people carry the vapA gene.
- Infection in immunocompetent people can be fatal in approximately 11% of cases, but among HIV-infected patients the mortality rate from R. equi infection can be as high as 50% to 55%.
Rhodococcus equi is actually a soil organism, and this is likely the most common source of the organism for both horses and people. Only approximately 1/3 of humans infected with R. equi report that they have had contact with horses or pigs (pigs can also carry the bacterium). So we don't know how much of a risk an infected foal is to a person. However, it is prudent for people, particularly those with weakened immune systems, to take precautions to avoid potential transmission of R. equi from horses.
- Try to reduce dust levels on the farm. Because R. equi most often lives in the soil, it can get stirred up into the air in dusty areas, which can then lead to inhalation by animals and people. Doing things like planting grass or other vegetation, installing windbreaks in high-traffic areas, or wetting down dusty stalls or paddocks can help reduce dust levels in the air.
- Keep open wounds and other broken skin covered when working around animals.
- Always wash your hands after handling a foal (or any horse)
- If you have a foal that develops signs of R. equi infection, make sure you have your veterinarian examine it as soon as possible so the diagnosis can be determined and the foal can be treated properly as soon as possible. Some foals with R. equi may develop severe pneumonia very quickly, so it’s important that they are examined right away.
Garden veggies and poopy parasites
Spring appears to have finally sprung in earnest in Southern Ontario (although we may still get one more frost on the weekend, so I hear) and people are getting back out into the garden. An increasingly popular trend in recent years, particularly this year now that the Obama's are doing it too, is vegetable gardening. Lots of people like the idea of growing their own veggies in their own backyard, or perhaps in a community garden plot for city dwellers who still want to get their hands dirty - it's economical, good for the environment, and the plants can be grown "organically" without the use of chemicals or pesticides. However, pesticides and garden bugs aren't always the only things to worry about having on your fresh veggies. We received the following comment from a Worms&Germs reader:
"...What if veggies get infected with raccoon stool[?] Can eggs be killed after [the] veggie is grown and ready to eat?"
Great question. The concern in the case of raccoon stool is the eggs of the roundworm Baylisascaris procyonis, which can be passed in huge numbers by a relatively high percentage of raccoons in many regions. If swallowed, the eggs release larvae which can migrate through the tissues of the body, rarely causing visceral, ocular or neural larval migrans.
The good news:
- Raccoons like to defecate in the same areas most of the time, usually on a relatively flat, elevated surface (e.g. woodpile). These areas become raccoon "latrines", and the soil in the area can become very heavily contaminated with roundworm eggs. The good part is that most raccoons therefore not defecate in your garden.
- Vegetables cannot become "infected" by the parasite - the eggs cannot be absorbed or otherwise get inside a vegetable, they can only contaminate the parts of the plant that are directly in contact with soil.
The bad news:
- Even though raccoons may not poop in your garden, they can still track roundworm eggs into the soil on their fur or paws when they come by to explore your crop, so you should always consider soil outside as potentially contaminated.
- Baylisascaris eggs are highly resistant to disinfectants and chemicals, so they can't be killed this way.
- Raccoon roundworms aren't the only parasites that may be found in garden soil. Dogs and cats can carry other roundworms (Toxocara spp.) which are also capable of causing larval migrans if swallowed (although infection with these worms in dogs and cats is not nearly as common as infection with Baylisascaris in raccoons). Cats in particular, unfortunately, do sometimes like digging in gardens and may sometimes use a garden as a litterbox.
- Soil, particularly if it's contaminated by the stool of any animal, can also contain many different kinds of bacteria such as Salmonella. Even if you can somehow protect your garden plot from animals, purchased garden soil and fertilizers may contain or may have come in contact with animal stool somewhere along the way.
So how do you make your garden veggies safe to eat?
- Wash wash wash: Because Baylisascaris eggs are so difficult to kill, the best thing to do is physically remove them from all surfaces of your vegetables by washing thoroughly to remove all visible dirt before doing anything else. If you cut into a vegetable before washing it, the soil on the outside can contaminate the inside.
- Peel peel: Peeling vegetables ensures that all dirt (including any dirt stuck in tiny crevices on the vegetable's surface, or dirt you may not be able to see with the naked eye) is removed prior to consumption, but it's still crucial to wash the veggie first (and your hands) before peeling.
- Cook: From an infection control perspective, it's best to cook vegetables before eating them. This actually won't do anything to Baylisascaris eggs - these have to be removed by washing and peeling - but it does help kill bacteria that either contaminated the veggies out in the garden or that contaminated the veggies during their preparation in the kitchen. For those of us who like our nice crunchy vegetables, obviously cooking them won't do, therefore washing and peeling become that much more important.
And, of course, always wash your hands thoroughly with soap and water after you've been working in the garden, even if you wear gloves.
In a lot of urban areas, it's hard to prevent raccoons and other animals from getting into yards and gardens. There are things you can do to discourage raccoons from hanging around your house, and if raccoons establish a latrine on your property it must be very carefully cleaned up. For more information on Baylisacsaris, raccoons and cleaning up raccoon latrines, please see our archives.
