'Extremely high' number of pneumonia cases strike kids in Ohio county

an illustration of red bacterial cells shaped like rods and spheres

A type of bacteria called Mycoplasma pneumoniae has caused some of the infections. (Image credit: Dr_Microbe via Getty Images)

An Ohio county has reported an "extremely high" number of pneumonia cases among kids this fall. There's no evidence that these cases are tied to an unusual or unknown cause; they've been attributed to known respiratory pathogens.

China and several European countries, including Denmark, have also reported significant upticks in pneumonia this year. A bacterium called Mycoplasma pneumoniae has been highlighted as a key culprit in these outbreaks.

The same microbe has been implicated in the outbreak in Warren County, Ohio, alongside a mix of other common respiratory pathogens, Dr. Clint Koenig, a family physician and medical director at the Warren County Health District, told The Washington Post.

However, "there has been zero evidence of [the Ohio] outbreak being connected to other outbreaks, either statewide, nationally or internationally," Warren County officials reported in a Nov. 30 statement.

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Between August and the end of November, Warren County saw 145 cases of pneumonia in children ages 3 to 14. The number of cases exceeds the county's yearly average and meets the Ohio Department of Health's definition of an outbreak, but the severity of the cases has not been unusual. No one has died, and most of the sick children have recovered at home with antibiotics, implying bacteria were the suspected or confirmed cause of most of the infections.

In addition to M. pneumoniae, clinical samples taken from the sick children have tested positive for Streptococcus pneumoniae and for adenoviruses, according to a Nov. 29 statement from the health district. These are also common respiratory bugs. Symptoms of the infections have included cough, fever and fatigue.

M. pneumoniae tends to cause outbreaks in the U.S. every one to three years, and the country hasn't seen big waves since before the COVID-19 pandemic, CNN reported. This could be related to children being less likely to be exposed to the bacteria due to pandemic-related restrictions, resulting in a large pool of kids who lack immunity, NBC reported.

"We expect that there are going to be some seasons that are worse than others for Mycoplasma infections, and it certainly seems that, across the U.S. and Europe, that this year might be worse than other years," Dr. C. Buddy Creech, a pediatric infectious disease specialist at Vanderbilt University, told CNN.

Some media outlets have referred to the M. pneumonia cases as "white lung syndrome," but this is not a term health officials use in reference to the infection, The Washington Post reported. However, the bacterium is a common cause of walking pneumonia, so called because it typically does not require hospitalization, Dr. Paul Offit, a professor of pediatrics at Children's Hospital of Philadelphia, told the Post. 

The Centers for Disease Control and Prevention (CDC) continues to monitor respiratory infections among kids, "including potential elevated rates of pediatric pneumonia in parts of the United States," the CDC website reads. Thus far, "these reported increases do not appear to be due to a new virus or other pathogen but to several viral or bacterial causes that we expect to see during the respiratory illness season."

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Nicoletta Lanese
Channel Editor, Health

Nicoletta Lanese is the health channel editor at Live Science and was previously a news editor and staff writer at the site. She holds a graduate certificate in science communication from UC Santa Cruz and degrees in neuroscience and dance from the University of Florida. Her work has appeared in The Scientist, Science News, the Mercury News, Mongabay and Stanford Medicine Magazine, among other outlets. Based in NYC, she also remains heavily involved in dance and performs in local choreographers' work.