Tularemia: A Rare but Nationally Notifiable Disease

The pediatrician’s first patient of the day was an 8-year-old boy, accompanied by both of his parents. It was the boy’s third visit in just over a week, for fever and left-sided neck swelling, and the family was understandably anxious for answers.

“The antibiotics don’t seem to be working,” the mother explained. “He still has fever every day as high as 104 and his neck looks just as swollen.”

A quick review of the chart revealed that the boy’s initial diagnosis had been bacterial lymphadenitis, for which amoxicillin-clavulanate had been prescribed. Three days later, given the lack of clinical improvement, therapy was transitioned to clindamycin. On exam, the boy was febrile and ill-appearing, with a 3 x 5-cm tender, nonfluctuant swelling over the left sternocleidomastoid muscle. 

The pediatrician ran through a quick mental checklist of diagnostic possibilities for his patient’s continued symptoms. Staphylococcal lymphadenitis still seemed possible. Could the boy be infected with methicillin-resistant Staphylococcus aureus that was also clindamycin resistant? Alternately, perhaps the problem was “source control” and the boy had developed an occult neck abscess that needed to be drained. Ultrasonography could help sort that out. Finally, the pediatrician considered less common bacterial causes of lymph node swelling and fever. He placed Bartonella henselae, the cause of cat-scratch disease, near the top of his list. “I’ve never seen it,” he told the parents, “but we could also consider tularemia.”

Tularemia is a rare zoonotic infection caused by Francisella tularensis. On average, 200 cases of tularemia are reported in the United States each year, and the incidence of disease is increasing, according to a surveillance report released by the Centers for Disease Control and Prevention in January 2025. Between 2011 and 2022, a total of 2462 tularemia cases were reported in the United States. That translated to an average annual incidence of 0.064 per 100,000 population, an increase of 56% compared with 2001-2010. Forty-seven states reported at least one case of tularemia, although half of all reported cases came from four states: Arkansas (18%), Kansas (11%), Missouri (11%), and Oklahoma (10%). The incidence of tularemia was highest in children ages 5-9 years, older men, and American Indian or Alaska Native individuals. Although cases occurred year-round, 78% showed symptom onset in May through September. 

In the United States, most human cases of tularemia historically have been arthropod borne, transmitted by the bite of an infected tick or deer fly. Infection can also be spread through contact with infected animals or animal tissue, particularly rabbits, hares, muskrats, prairie dogs, and other rodents, including hamsters. Outbreaks of tularemia have occurred among pet store hamsters, and at least one child in the United States developed tularemia after being bitten by a pet hamster.

Tularemia is almost always associated with fever, but other clinical manifestations vary by the type of exposure. Ulceroglandular disease occurs after a tick or deer fly bite, or after handling an infected animal. An ulcer develops at the site where the bacteria enter the body, along with enlargement of regional lymph nodes. Less commonly, lymph node swelling can occur without the development of an ulcer. If the bacteria enter through the eye, symptoms include conjunctivitis and swelling of preauricular lymph nodes. Eating or drinking contaminated food or water is associated with sore throat, mouth ulcers, tonsillitis, and swelling of lymph glands in the neck. Pneumonic tularemia, the most serious form of the disease, typically happens after inhaling bacteria-containing dust or aerosols and is associated with cough, chest pain, and difficulty breathing. Pneumonic tularemia can also develop if other forms of tularemia are untreated and the bacteria spread to the lungs.

Back in the exam room, the pediatrician carefully reexamined the boy’s scalp. A poorly healing 1-cm ulcer on the left occiput added support for the diagnosis of ulceroglandular tularemia, the most common form of the disease in children. Serologic testing ultimately confirmed the diagnosis and the boy’s symptoms resolved with treatment.

Gentamicin administered intravenously or intramuscularly is the treatment of choice for tularemia in children. Ciprofloxacin is considered an alternative but is not approved by the US Food and Drug Administration for this indication.

The pediatrician reported the case of tularemia to his local health department. Tularemia is a nationally notifiable disease in the US; state health departments report to the CDC through the National Notifiable Diseases Surveillance System. In turn, public health authorities share information to prevent tularemia.

Steps to prevent tick and deer fly bites include the use of an Environmental Protection Agency-registered insect repellent. Individuals who hunt, trap, or skin animals are encouraged to wear gloves while handling animals, especially rabbits, muskrats, and prairie dogs, and to cook game meat thoroughly. Tularemia can be inadvertently aerosolized if an infected animal or carcass is run over with a tractor or lawnmower. Checking for carcasses before mowing may reduce the risk.