Rare rabbit fever cases in the U.S. are on the rise; 5 Tularemia symptoms to watch out for

What was supposed to be a rare disease that, for some reason, typically affects people from the Northern Hemisphere, has been getting the attention of health officials lately because of a sudden increase in the number of cases reported in some U.S. states.

According to the Centers for Disease Control and Prevention (CDC), a total of 100 cases of people infected with rabbit fever or tularemia were already reported as of September 30 among residents from Colorado with 43 cases, Nebraska with 21, South Dakota with 20 and Wyoming with 16. During the last two decades, the average annual cases of tularemia reported in the country is 125.

Tularemia, which can also be life-threatening at times, is caused by the bacterial cell Francisella tularensis. According to a report from Wral.com, health officials are still clueless as to why there is a sudden surge in the number of cases, but speculate that it may have been due to the weather conditions favorable to rodents.

The bacteria from rabbits or other small mammals are usually contracted by ticks and deer flies and can be transmitted to humans when bitten. People could also be exposed to the bacteria by handling dead animals.

According to Mayo Clinic, the symptoms of the infection vary, depending on the type of tularemia acquired by the patient. There are different types of rabbit fever infection, according to how and where the bacteria went into the body.

Here are 5 types of the disease and their corresponding symptoms to watch out for.

• For ulceroglandular tularemia, which is the most common form of the disease, symptoms include skin ulcer that forms at the site of infection, swollen and painful lymph glands, fever and chills. When these symptoms manifest except for skin ulcers, then the disease is referred to as glandular tularemia.

• Oculoglandular tularemia, on the other hand, includes symptoms like eye pain, eye redness, eye swelling and discharge, an ulcer on the inside of the eyelid and sensitivity to light.

• Oropharyngeal tularemia, which is typically a result of consuming improperly cooked wild animal meat or drinking contaminated water, includes symptoms like fever, throat pain, mouth ulcers, vomiting, inflamed tonsils and swollen lymph nodes in the neck.

• Pneumonic tularemia's signs and symptoms include dry cough, chest pain and difficulty breathing.

• Typhoidal tularemia, meanwhile, is the more serious type of the disease and may cause high fever, extreme exhaustion, vomiting and diarrhea, enlarged spleen, enlarged liver and pneumonia.