What is rat bite fever? The infection explained

Library picture of a pet rat similar to one which bit Chris Hammond from Leicester Credit: PA

What is 'rat bite fever'?

Rat-bite fever is a rare infection caused by the Streptobacillus moniliformis bacterium which is carried in rat saliva. It is rarely diagnosed in England & Wales - with around one or two cases per year.

Transmission

Human infection is usually through the following ways:

  • from a rat bite/scratch

  • handling infected rats

  • ingestion of milk or water contaminated with the organism (via rat urine)

Person-to-person transmission does not occur.

Symptoms

Rat-bite fever usually develops within 7 days of the bite

  • It begins abruptly with fever and chills

  • Followed by severe swelling and joint pain, headache and nausea

  • Many patients develop a rash, most often on the extremities

  • About half of all patients develop a non-suppurative arthritis

  • a minority of cases have a form of non-bacteraemic disease with septic arthritis

Treatment

The infection can be successfully treated with antibiotics; penicillin is the treatment of choice.

What to do if you think you're infected

The advice if you are bitten by a rat and think you are showing symptoms is to go to your local GP or hospital. The infection is only dangerous if left untreated and after a course of antibiotics the illness has no long term effects.

Source: Health Protection Agency