Backyard Hazard Series: Seoul Virus

The Backyard Hazards series of articles focuses on the diseases that you or your pet may be at risk of contracting, right in your own backyard.
WHAT IS SEOUL VIRUS?
Seoul virus (SEOV) is a type of zoonotic virus (meaning it can be spread between humans and animals) known as a hantavirus that is seen throughout the world in both wild and domestic rats. It is most commonly sees in the Black Rat (Rattus rattus) and the Norway Rat (Rattus norvegicus).
Commonly, pet rats are from the same species of rats as the Norway Rat but appear in different varieties (Fancy, Hairless, Dumbo, Rex, etc.).
In December 2016, Ontario saw its first few positive cases of SEOV surface. Since then, both humans and rats have tested positive in an outbreak that has encompassed both Canadian and American rat-breeding facilities.
Since this outbreak was detected, Public Health Ontario, the Ministry of Health and Long-Term Care, Local Public Health Units, Ontario Ministry of Agriculture, Food and Rural Affairs, Public Health Agency of Canada and the U.S. Centers for Disease Control have been working together to monitor this outbreak and provide direction to rat owners.
HOW CAN RATS GET SEOUL VIRUS?
Rats who have contracted the Seoul virus will shed the virus through urine, feces and saliva. The virus is then passed to other rats when they come into contact with these, or when they are bitten by an infected rat.
HOW CAN PEOPLE GET SEOUL VIRUS? 
Just like when rats pass the virus to other rats, humans can become infected when they come into contact with an infected rat’s urine, feces and saliva. This may occur when handling feeder rats (fresh or frozen food for reptiles) or pet rats, receiving a bite from an infected rat or while cleaning out their bedding in their cage. Sweeping and vacuuming rat habitats while cleaning should be avoided as the virus can be aerosolized and inhaled. People do not pass the Seoul virus to other people.
WHAT ARE THE SIGNS OF SEOUL VIRUS?
In rats Rats that have Seoul virus do not show signs or symptoms. Once a rat has Seoul virus it will shed the virus for life and may pass the virus along to other rats and people.
In people
Some humans may not show signs of SEOV infection either. Although, others may present with flu-like symptoms one to two weeks after exposure to the virus that include:
  • Headache
  • Backache
  • Abdominal pain
  • Fever and chills
  • Nausea
  • Blurred vision
  • Redness/inflammation of the eyes
  • Flushed face • Rash
The CDC states: “While Seoul virus infection in humans is generally considered less severe than some other types of hantavirus infections, it can still cause a severe illness in some cases. Some people may develop a severe form of infection known as hemorrhagic fever with renal syndrome (HFRS), and an estimated 1% to 2% of people may die after being infected with Seoul virus.”
In these more severe cases the following may be seen:
  • Kidney failure
  • Low blood pressure
  • Signs of bleeding
  • Shock
  • Death
Those who are pregnant, children, elderly and immunocompromised may be more at risk of developing disease.
WHAT SHOULD I DO IF I AM CONCERNED MY RAT HAS SEOUL VIRUS?
There is no specific treatment available for rats with SEOV. In some cases, blood testing can be performed on live rats to test for Seoul virus. If you are concerned that your pet rat may be carrying the Seoul virus you should reach out to your local public health unit to inquire what your next steps should be.
People who have developed symptoms of Seoul virus may be treated with supportive care until the virus runs its course.
WHAT STEPS CAN I TAKE TO KEEP MYSELF SAFE WHEN CLEANING MY RAT’S HABITAT?
First, clean the habitat in an area that is well ventilated. Cleaning outside is best if possible. If cleaning must occur indoors, make sure to open windows 30 minutes prior to cleaning and avoid areas where food is prepared. The CDC recommends the following steps when cleaning rat habitats:
FIRST, CLEAN UP ANY URINE AND DROPPINGS 
When you begin cleaning, it is important that you do not stir up dust by sweeping or vacuuming up droppings, urine or nesting materials. Wear rubber, latex or vinyl gloves when cleaning urine and droppings. Spray the urine and droppings with a disinfectant or a mixture of bleach and water and let soak five minutes. The recommended concentration of bleach solution is one part bleach to 10 parts water. When using a commercial disinfectant, follow the manufacturer’s instructions on the label for dilution and disinfection time.
Use a paper towel to pick up the urine and droppings, and dispose of the waste in the garbage. After the rodent droppings and urine have been removed, disinfect items that might have been contaminated by rodents or their urine and droppings.
NEXT, CLEAN AND DISINFECT THE WHOLE AREA
Mop floors and clean countertops with disinfectant or bleach solution. Steam clean or shampoo upholstered furniture and carpets with evidence of rodent exposure.
Wash any bedding and clothing with laundry detergent in hot water if exposed to rodent urine or droppings. Lastly, remove gloves, and thoroughly wash hands with soap and water (or use a waterless alcohol-based hand rub when soap is not available and hands are not visibly soiled).
Rats make great family pets and it is important to note that not all rats carry Seoul virus. If you are considering a rat as a pet for your family, it is important to look into the breeder you are considering purchasing your rat from and inquiring about their rattery’s Seoul virus status. A reputable rat breeder will not breed and sell infected rats and should be able to provide proof to you that their rattery is free from the virus. More information about the virus can be found on Public Health Ontario’s website www.publichealthontario.ca by searching “Seoul virus.”
Kristina Cooper is a Registered Veterinary Technician (RVT) and proud member of the Ontario Association of Veterinary Technicians (OAVT). She has previously worked in both small animal practice and a municipal animal shelter. With a special interest in the relationship between animal and human health she is currently the Provincial Manager of the OAVT Public Health Rabies Response Program and an active One Health Initiative advocate. She can be reached by email at krizzteena@hotmail.com

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