Rat Bite Fever

Rat bite fever is a disease caused by an infection by one of two different bacteria. Streptobacillus moniliformis and spirillum minus are the bacteria and they are regular bacteria found in the respiratory systems (mouth, nose, and lungs) of rodent in North America and Asia, respectively. Rats are carriers of the disease, meaning that they do not get ill from the different bacteria. This is a serious illness, but prompt medical attention can reduce severity.

How common is it and who is at risk?

Anyone is at risk for this infection if they are exposed to the bacteria. People who have compromised immune systems always have a heightened risk for any infection because their bodies are not as suited for fighting them off. One hypothesis is that dense urban populations are also at a higher risk for the infection due to the larger population of rodents in these areas. People who work in labs or breeding facilities or live with rats as pets have a higher possibility of contracting it as well.

How is it transmitted?

Rats transmit this infection through bites and scratches, even minor ones. Pet rat owners can catch the disease from close contact with their animals. It can also be present in contaminated food or drink, such as unpasteurized milk or juice. When it is contracted by swallowing these contaminated foods or drinks, it is known as Haverhill Fever.

What are the symptoms?

The symptoms can differ from the illness caused by North American bacteria to that of the illness caused by the bacterium in Asian rodents. The North American version has an incubation period of up to 3 weeks after exposure and the symptoms include a headache, fever, and nausea. It can also cause a bumpy red rash on the hands and feet and 1 or more joints to swell and be painful.

The Asian form will show in 7 to 21 days as fever, swollen lymph nodes, swelling or additional open sores near the bite/scratch site, and a rash is also possible. Haverhill fever has symptoms of nausea, severe vomiting, fever, and sore throat.

With treatment, these symptoms will be kept mild and the person will recover fairly quickly. If treatment is not sought out quickly, it can lead to meningitis, pneumonia, myocarditis, endocarditis, or sepsis.

How is it diagnosed and treated?

It is important to seek medical attention as soon as you believe that rat bite fever is a possibility. The person must make sure to tell their doctor if they work with rodents or have recently handled one so that they can be sure to test for rat bite fever. A tissue or blood sample can be taken to test for the disease.

If the test is positive, antibiotics are administered with positive results. If the person waits too long, and the disease becomes severe, treatments will be needed depending on the organs or systems that are being affected.

How can it be prevented?

It is important to avoid unnecessary contact with wild rodents. If an infestation is a problem, a professional should be called so that it can be handled quickly and successfully. If a person owns a pet, they must make sure to understand safe handling and care of the rodent. It is also necessary to practice proper hygiene after handling the pet as well.

If a bite or scratch does happen, it needs to be cleaned immediately. It is also a good idea to seek medical attention to make sure that no infection has occurred.

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