Rat-bite fever: symptoms, treatments, and care

Rat bite fever is also known as streptobacillary fever or spirillary fever. As the name implies, it is caused by the bite of an infected rat, but it can also be caused by mice, weasels, squirrels, cats or any animal that feeds on a sick rat.

These animals attack when they feel cornered or pressured. These types of accidents have become more common, as the number of rodents has increased due to climate change. In 10 cases, 1 develops rat-bite fever.

What does a rat bite look like?

The rat bite looks like a wound small and sharp. Sometimes what is seen is a series of small bites. Usually they are not serious, but it is common for them to cause bleeding and painful inflammation.

The wound caused by one of these bites can also become infected. In that case, you may see some pus in the area. The most serious complication is rat bite fever, but this does not appear immediately.

The usual thing is that the wound heals and later the rise in temperature appears. This takes place in a period ranging from 1 to 20 days after the bite. Symptoms appear abruptly and become very severe.

Rats are vectors of various diseases, both bacterial and viral. Their presence in homes requires care.

Read on: What is hantavirus?

How do you know if you have rat bite fever?

Rat bite fever can be caused by two microorganisms. One of them is bacteria S. moniliformis. The other is S. minus. In the first case we speak of streptobacillary fever and, in the second, spirillary fever.

In both cases there are symptoms that are common: fever, chills and headache. There are also particular signs of each one. In the case of streptobacillary fever, in addition to those already mentioned, the following appear:

  • Red rash, especially on the arms and legs.
  • Muscle pain.
  • Arthritis, usually concentrated in the knee.
  • Vomiting and diarrhea

Complications of rat bite fever include serious health problems, such as pneumonia, meningitis, abscesses, and inflammation of the heart. In spirillary fever, on the other hand, these symptoms appear:

  • Ulceration at the site of the bite. Red spots form around it.
  • Swelling of the lymph nodes.
  • Skin rash with red, purple, or brown patches.

Complications include pneumonia, hepatitis, meningitis, and heart infection. Another modality is what is known as Haverhill fever. In that case, there is also vomiting and a sore throat.

Read also: The most used natural remedies against insect bites

What is the treatment for rat bite fever?

What is indicated is that, after the bite, wash the affected area with soap and warm water as quickly as possible. You have to dry yourself with a clean towel and apply an antibiotic ointment. Then cover the wound with a sterile bandage.

The doctor should always be consulted, even if the wound appears to be minor or barely noticeable. The professional is likely to order a tetanus shot or to prescribe antibiotics to anticipate an infection.

In these cases, follow-up should be done and be attentive to the appearance of any of the symptoms of rat bite fever. If this occurs, Antibiotics will be prescribed for 7 to 10 days. If the case is severe, they will be administered intravenously.

What complications are there without treatment?

If proper and timely treatment is not administered, various complications may appear. Untreated rat bite fever can lead to very serious problems. Some of them are deadly, like the following:

  • Cardiac: myocarditis, endocarditis and pericarditis.
  • Circulatory. systemic vasculitis and polyarteritis nodosa.
  • Others: pneumonia, hepatitis, nephritis, meningitis, and focal abscesses.

Rat-bite fever can lead to life-threatening pneumonia.


Typically, a person with rat-bite fever recover after one week of taking prescribed antibiotics. In some cases, the fever can return. Sometimes this happens for weeks or months, but goes away over time.

This disease cannot be spread from person to person. The greatest danger is that the prescribed approach is not followed properly or is not carried out completely. In those cases, it can lead to death.

Rat bite fever is to watch out for

It is extremely important that people affected by rat bite fever adhere to treatment to the letter. Interrupting it or not advancing it properly can lead to it becoming ineffective. This is dangerous and even deadly.

Many people have chosen to keep rats as pets. No matter how much affection you have for them, whenever there is a bite you should follow the recommendations already mentioned. In all cases it is essential to consult with the doctor and follow the protocols established by the health authorities.