Rat scratch fever?

Dear Alice,

I just got clawed by a rat in a nearby park. It jumped off of the top of a trashcan, hit my leg, twisted around and clawed my leg, broke skin with three claws. I cleaned it out really well, but what else should I do?

Dear Reader,

That must have been quite a stroll in the park! While you’ve gotten a good start on caring for your recent run-in of the rat-kind, it’s a good idea to keep a look out for symptoms of infection in the days after the encounter. First, the good news: according to the Centers for Disease Control and Prevention (CDC), rats, despite their fearsome reputation, almost never carry rabies; so, even if you were bitten instead of clawed, it's unlikely that you'll start foaming at the mouth. However, there is a bacterial infection, referred to as rat-bite fever (RBF) that might be of concern. If you start experiencing symptoms associated with RBF (read on for more on those), it may be time to hightail it to the nearest medical facility.

Though RBF may seem limited to those who’ve been bitten by a rodent, you can actually get the infection from rat scratches and contact with contaminated food or drinks (this is referred to specifically as Haverhill fever) as well. The infection is caused by one of two types of bacteria: Streptobacillus moniliformis (most common in North America) or Spirillum minus (more common in Asia). Symptoms do vary slightly depending upon which bacteria causes the infection.

RBF symptoms associated with Streptobacillus moniliformis bacteria typically occur within three to ten days after contact with an infected rodent and can include:

  • Chills and fever
  • Rash
  • Pain, redness, or swelling in the joints

If Spirillum minus bacteria is the cause for RBF, symptoms tend to show up around 7 to 21 days after contact. Some of the symptoms are similar to those caused by a Streptobacilliary RBF infection (except for pain, redness, or swelling in the joints) and may also include:

  • Open ulcers and swelling near the site of the rodent bite
  •  Swelling of lymph nodes

If any of these symptoms do occur, immediate medical treatment is necessary. Without treatment, it is possible (though rare) for this infection to become quite serious, resulting in further infections of the heart, brain, and lungs — and it can even be fatal. That being said, you’ll be happy to know that RBF is easily curable with a round of prescription antibiotics.

Even though you have cleaned the wound thoroughly, your best bet may be to check-in with your health care provider to make sure that there are no signs of infection. Also, keep a close watch on the wound, noting any changes in case it doesn't heal properly and reporting them to your provider. Once you receive a clean bill of health, you can regale your friends and acquaintances with the legend of your rat attack.

Last updated Nov 27, 2015
Originally published Mar 23, 2001