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Disclosures: Traxler reports no relevant financial disclosures.
July 02, 2020
2 min read

Rat-bite fever more prominent in children, young adults

Disclosures: Traxler reports no relevant financial disclosures.
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Rat-bite fever occurs rarely in the United States, but is more prominent in children compared with other populations when it does occur, according to findings published in in Open Forum Infectious Diseases.

“Rat-bite fever is a serious and potentially fatal bacterial zoonotic disease,” Rita Traxler, MHS, an epidemiologist with the CDC, told Healio. “It can be spread to people through contact with rats and other rodents, directly through bites or scratches; from close contact with rodent saliva, urine or droppings; or from surfaces contaminated with the bacteria. It can cause serious health problems and, if untreated, is estimated to lead to death in about one in 10 cases.”

Small rat
Rat-bite fever is rare and primarily affects people aged 0 to 19 years.
Source: Adobe Stock

According to Traxler, because rat-bite fever is rare, there is little information available about the burden of rat-bite fever in the U.S. or who might be at the most risk of illness.

“To find out more, we used health care encounter data sources to estimate the burden of health care visits associated with rat-bite fever and rat bite injuries,” she said. “We hope that these estimates will provide a baseline from which we can build additional research on risk groups and target communication messages to specific groups at risk for contracting rat-bite fever.”

Traxler and colleagues analyzed rat-bite fever and rat-bite injury diagnoses in the U.S. between 2001 and 2015. The researchers examined national, state and Indian Health Service health care encounter datasets for rat-bite fever and rat-bite injury diagnoses and determined average annual encounter rates per 1,000,000 persons.

According to Traxler, the study results showed that health care visits for rat-bite fever were rare. Nationally, the disease accounted for an average annual ED visit rate of 0.33 per 1,000,000 persons (95% CI, 0.19-0.47) and an average annual hospitalization rate of 0.2 per 1,000,000 persons (95% CI, 0.17-0.24).

The researchers estimated that 27, 31, 38 and 35 rat-bite fever hospitalizations in children and young adults aged 0–19 years occurred in 2003, 2006, 2009, and 2012, respectively, with 21, 35, 22 and 20 concurrent hospitalizations related to rat-bite injuries. Annual rat-bite fever hospitalization rates were lowest in 2003 (0.33 per 1,000,000 U.S. children and young adults aged 0–19 years; 95% CI, 0.10-0.50) and highest in 2009 (0.46; 95% CI, 0.20–0.70). The rat-bite injury hospitalization rate was lowest in 2012 (0.25; 95% CI, 0.10-0.40) and highest in 2006 (0.42; 95% CI, 0.20-0.60).

“We were interested to learn that the hospitalization rate was almost twice as high among children and teens,” Traxler said. “Based on cases for which CDC has received information, cases in children are often related to close contact with pet rats. Children may interact with pets more closely, including kissing or nuzzling, compared to adults.”

The results also showed that rat-bite fever hospitalizations occurred more often among white people and among people with private insurance, whereas rat bite injury hospitalizations did not. According to Traxler, better access to care and diagnostic capacity for rat-bite fever among people of white race and people with private insurance could explain this finding.

“Clinicians treating patients with an illness compatible with rat-bite fever should collect thorough social and occupational histories,” Traxler said. “Social history questions should include whether the patient has pets, especially rodents, and whether they have had contact with pet, wild rats or other rodents within 3 weeks.”