An image of Fusobacterium necrophorum, a type of bacteria that is the most common cause of Lemierre syndrome, a rare infection that's been dubbed a "forgotten disease."

A college student-athlete in Kansas died suddenly from a rare bacterial infection after thinking her symptoms were due to tonsillitis, according to news reports.

The 23-year-old, Samantha Scott, was a top coxswain on the rowing team at Kansas State University, according to a statement from the university. But about two weeks ago, she started to feel unwell.

Initially, it was thought that Scott had tonsillitis, or inflammation of the tonsils, according to local news outlet KDVR. Tonsillitis can cause symptoms such as sore throat, fever and pain when swallowing. But Scott had actually developed an illness called Lemierre syndrome, a condition that's so rare it was referred to as "all-but-forgotten disease" in a 2006 report of a similar case. [27 Oddest Medical Cases]

Lemierre syndrome is a bacterial infection that begins in the throat and causes symptoms such as sore throat and fever, followed by swelling of one of the jugular veins in the neck, according to National Institutes of Health's Genetic and Rare Diseases Information Center (GARD). Later, pus-filled tissue moves from the throat to various organs, including the lungs.

A number of different bacteria can cause Lemierre syndrome, but the most common is Fusobacterium necrophorum, a type of bacteria that can be found in the throat, even among healthy people.

Indeed, the condition often appears in healthy young people, but exactly why it develops is poorly understood. One theory is that certain viruses or other bacterial infections may allow the F. necrophorum bacteria to invade the mucous membrane in the throat, GARD says.

The condition can be treated with antibiotics, but quick action is needed, as a delay in diagnosis by four or more days leads to significantly worse outcomes, GARD says. Unfortunately, the diagnosis is often delayed because of the initially innocuous symptoms and lack of awareness of the disease, the 2006 case report said.

Despite being called a "forgotten disease," the syndrome appears to be becoming more common as doctors have tried to rein in their use of antibiotics, according to University of Alabama at Birmingham (UAB). About one in 70,000 young adults develops the condition each year, and about 6 percent die from the disease, UAB said.

Scott passed away on Saturday (Oct. 27).

Scott's family has started a GoFundMe campaign to cover the expenses from the medical bills and funeral costs. The family is also looking to start a scholarship fund on behalf of Scott for the Kansas State University rowing team, according to the GoFundMe page.

"Sam was known for her positive outlook on life and her contagious smile," her family wrote. "Those who knew her closely are able to talk in depth about her outgoing personality and ability to cheer anyone up."

Originally published on Live Science.