Playing the Salmonella Card
by Web Wheeler
July 24, 2012
A short while ago a Toronto grade school teacher was praised in the Toronto Star newspaper for his efforts to educate students about the wonders of reptiles. Here's a link to that Toronto Star article:
Less than 24 hours later, an entry on the University of Guelph "Worms and Germs Blog", by Dr. Scott Weese, Associate Professor in the Department of Pathobiology at the University of Guelph and Public Health and Zoonotic Disease microbiologist for the University's Centre for Public Health and Zoonoses, was critical of the Toronto teacher's effort, saying, "The sentiment is great and I applaud the teacher's efforts to engage kids and teach them about animals, However, it's a cost/benefit situation and the potential costs (which may be extreme) outweigh the benefits (significant as they may be). While reptiles can be great pets in certain situations, they're not meant for schools where there are lots of kids, challenges with supervision, difficulty implementing good infection control practices and potentially individuals at high risk for infection."
Here's a link to the "Worms and Germs Blog" entry:
I am indeed surprised by this critical blog post by Dr. Weese, and here's why:
Salmonella is ubiquitous in the environment
Salmonella is ubiquitous in the natural environment, and many opportunities exist for cross-contamination during the production, harvest, processing and/or distribution of foodstuffs.(1)
Any raw food of animal origin, such as meat, poultry, milk and dairy products, eggs, seafood, and some fruits and vegetables may carry Salmonella bacteria.(2)
Contaminated food is the major mode of transmission
Contaminated food is the major mode of transmission for non-typhoidal salmonellae because salmonellosis is a zoonosis and has an enormous animal reservoir. The most common animal reservoirs are chickens, turkeys, pigs, and cows; dozens of other domestic and wild animals also harbor these organisms. Because of the ability of salmonellae to survive in meats and animal products that are not thoroughly cooked, animal products are the main vehicle of transmission. The magnitude of the problem is demonstrated by the following recent yields of salmonellae: 41% of turkeys examined in California, 50% of chickens cultured in Massachusetts, and 21% of commercial frozen egg whites examined in Spokane, WA.(3)
Every year hundreds of thousands of people are infected with food-borne Salmonella poisoning.(3)(4)
Traditional pets can also transmit Salmonella
Salmonella infections in dogs and cats deserve special comment for several reasons related to zoonotic transmission:
1. Salmonella spp. can be isolated from healthy dogs and cats at rates of up to 36% and 18%, respectively.
2. Dogs and cats tend to shed Salmonella organisms for very prolonged periods of time after infection.
3. Dogs and especially cats can shed Salmonella organisms in both their feces and saliva, meaning that transmission can occur via licking.
4. Pig ear dog treats may be a source of Salmonella infection for both dogs and humans that handle the treats.
5. Dogs and cats may suffer salmonellosis as a "reverse zoonosis," with infection transmitted from human-to-dog and subsequently back to other humans.
6. Similarly, outbreaks of Salmonella infections in large animal teaching hospitals have been linked to the introduction of bacteria from infected human personnel, with subsequent spread to animals and then back to other human workers.(5)
Dogs and cats can become ill due to a Salmonella infection and have diarrhea, fever, vomiting, decreased appetite, or abdominal pain; however, some dogs and cats may be asymptomatic. Like humans, some dogs and cats can become carriers and can infect other animals or humans.(6)
Dog food contaminated with Salmonella has [recently] sickened at least 22 people throughout the United States and two people in Canada, according to the latest update from the Centers for Disease Control an Prevention (CDC).(4)
Most cases of Salmonella poisoning do not require treatment
Most persons infected with Salmonella develop diarrhea, fever, and abdominal cramps 12 to 72 hours after infection. The illness usually lasts 4 to 7 days, and most persons recover without treatment.(6)
At least 40,000 salmonella infections are reported every year, but experts believe that between 400,000 and 4 million persons each year actually contract salmonellosis.(3)
Salmonella infections can be life-threatening for the very young, the very old and for persons already weakened by other serious diseases, such as AIDS. Reports show about 2 deaths for every 1,000 known cases of salmonellosis, but experts believe that about 500 persons each year actually die from salmonella infections.(3)
Author's Note: experts believe that about 500 persons each year actually die from salmonella infections out of the 400,000 to 4 million persons who contract salmonellosis every year.
Basic hygiene can help prevent Salmonella poisoning
Wash your hands thoroughly after contact with animal feces, pets, pet turtles, pet rodents, pet food, pet toys and pet treats.(7)
Is Dr. Weese overstating the risks of Salmonella poisoning from reptiles?
As a professional exotic animal breeder, as a researcher, as a citizen scientist, as a reptile and tropical fish enthusiast for over 40 years, I believe, in the case of the Toronto teacher, Jim Karkavitsas, who manages the Clinton Street public school reptile club, the answer is yes. The concerns which Dr. Weese raises, while valid, are all either expertly addressed by Mr. Karkavitsas or are not applicable to this situation.
Dr. Weese states "Salmonella. That's the big one. Reptiles are classic sources of Salmonella. You can almost guarantee that more than one of these reptiles are shedding the bacterium. If a reptile is shedding Salmonella in its feces, it will also likely have the bacterium on its skin, in its cage and in any areas where it roams. It also means that anyone touching it (or its environment, or contaminated areas) can pick up Salmonella on their hands, with subsequent transfer into the mouth. This is a high-risk situation since reptiles are a major source of salmonellosis, especially in kids. Reptile-associated salmonellosis does occur in classroooms."
Mr. Karkavitsas states "Kids use hand sanitizer before and after handling the animals."(8)
Dr. Weese's second concern is "Mr. Karkavitsas buys frozen rats to feed the snakes. Frozen rats can also be contaminated with Salmonella, and frozen rats have caused salmonellosis in kids in a school (which was also brought home and spread other family members). There's also been a large (and likely ongoing) international salmonellosis outbreak associated with frozen rodents."
The large (and likely ongoing) international salmonellosis outbreak associated with frozen rodents is limited to one rodent supplier in the U.S.(9) and is very unlikely to be applicable to this situation, as Mr. Karkavitsas gets all of his rodents from a local Toronto pet shop.(8)
The last concern Dr. Weese stated is "Standard recommendations are that children less than five years of age (along with pregnant women, elderly individuals and people with compromised immune systems) not have contact with reptiles. This is a grade 5-6 classroom, so the students would be older than this, but I wouldn't be surprised if younger kids in the school also have contact with the reptiles. Additionally, the immunocompromised group is an issue, since many people have compromised immune systems due to various diseases or treatments. Teachers may not know about all of these and parents may not realize that their high-risk child is having contact with high-risk animals in school. When you can't be sure that high-risk people won't have direct or indirect contact, that's a problem."
While the Clinton Street public school is for Kindergarten to Grade 6 students, there is no indication that kids under the age of five, or other high-risk individuals, are involved with this club.(8)
Some final thoughts
Allowing kids to have fun, to learn about the natural world, to have respect for animals, to overcome phobias and disruptive behaviors, to practice good hygiene and to aspire to become scientists(8) are all excellent traits that should be fostered both at school and in the home.
Yes, there are risks, but I strongly disagree with Dr. Weese's assessment "The sentiment is great and I applaud the teacher's efforts to engage kids and teach them about animals, However, it's a cost/benefit situation and the potential costs (which may be extreme) outweigh the benefits (significant as they may be). While reptiles can be great pets in certain situations, they're not meant for schools where there are lots of kids, challenges with supervision, difficulty implementing good infection control practices and potentially individuals at high risk for infection."
Kids risk contracting salmonellosis just by going to school, by eating in the school cafeteria, by using the school's washrooms, by playing with other kids at school and by the myriad of other school activities they engage in every day.
Rather than condemning the practice of hands-on-learning via a public school reptile club, Dr. Weese should instead be working closely with Mr. Karkavitsas and other school officials to ensure that his concerns are fully addressed and that kids are getting all the benefits that a public school reptile club has to offer.
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