White ratAnother day, another new zoonotic disease concern.

Well, it’s not really that bad, but the list of new (or at least newly identified) zoonotic disease issues continues to expand at an impressive rate.

One of the latest concerns is a cluster of Seoul virus infections linked to rats. At last report, 8 infections with Seoul virus have been identified in people in two US states.

Seoul virus is a member of the Hantavirus family, a group of viruses that lives primarily in rodents.  Seoul virus infections in people tend to be relatively mild. Most people who are infected do not develop any signs of disease, but flu-like illness and potentially some more serious complications such as kidney disease can occur. Relatively speaking, it’s much less serious than the life-threatening hantavirus pulmonary syndrome that can develop with other hantavirus infections, but it still warrants attention.

The first reported human case in this series was a at-home rodent breeder in Wisconsin. He ended up in hospital after developing fever, headache and some other vague flu-like symptoms. A family member subsequently tested positive as well. Fortunately, both recovered.

Since this is a rodent-borne virus, tracebacks to facilities from which this person obtained rats were pursued. Six additional human cases were identified associated with two rat-breeding facilities in Illinois. Efforts are ongoing to see if there are any infections in other people who purchased rats from any of these facilities.

One thing that was overlooked in this outbreak report is how the index case was identified. There’s not much information available, but Seoul virus testing isn’t routine, and testing of people with flu-like disease for things beyond influenza (if that) isn’t that common. A CNN news report about the Seoul virus outbreak said “Because of the patient’s exposure to rodents, the doctor had a “hunch” to test for hantavirus, explained [Director of the Wisconsin Dept of Health Services Bureau of Communicable Diseases Stephanie] Smiley.”

  • That’s an important point to me, as it shows that animal contact was queried (which unfortunately isn’t often done) and the information led to consideration of uncommon problems. We need more of this kind of behaviour to improve diagnosis of zoonotic diseases.

CDC’s recommendations for rat owners are pretty straightforward (and are what we tell rat owners to do at all times, since they also help reduce the risk of things like rat bite fever (Streptobacillus moniliformis infection)):

  • Wash your hands with soap and running water after touching, feeding, or caring for rodents, or cleaning their habitats. Be sure to assist children with handwashing.
  • Be aware that pet rodents can shed germs that can contaminate surfaces in areas where they live and roam. Make sure rodent enclosures are properly secured and safe, so your pet doesn’t get hurt or contaminate surfaces.
  • Clean and disinfect rodent habitats and supplies outside your home when possible. Never clean rodent habitats or their supplies in the kitchen sink, other food preparation areas, or the bathroom sink.
  • Avoid bites and scratches from rodents. Be cautious with unfamiliar animals, even if they seem friendly. Take precautions when cleaning out rodent cages or areas with rodent urine or droppings.
  • Visit your veterinarian for routine evaluation and care to keep your rodents healthy and to prevent infectious diseases.

If bitten by a rodent:

  • Wash the wound with warm soapy water immediately. Even healthy pets can carry germs.

Seek medical attention if:

  • Your pet appears sick.
  • Your wound is serious.
  • Your wound becomes red, painful, warm, or swollen.
  • Your last tetanus shot was more than 5 years ago.
  • You develop sudden fever or flu-like illness within 1-2 weeks after being bitten

Tell your healthcare provider that you have been around pet rodents, whether at home or away from home, especially if you are sick or have been bitten or scratched.