(NEXSTAR) — The Centers for Disease Control and Prevention is warning a virus that can cause serious illness or death in newborn babies is circulating in “multiple states” after it killed a baby boy in Connecticut.

The parechovirus, or PeV, is common in children – most kids will get it by the time they’re in kindergarten, according to the CDC – but it can have grave consequences for infants younger than 3 months old.

In older kids, between 6 months and 5 years old, the virus can cause an upper respiratory infection, fever, and rashes. But in very young infants, it can cause “sepsis-like illness, seizures, and meningitis,” the CDC says. Babies under 1-month-old are the most vulnerable.

The virus can be spread by people who are symptomatic and asymptomatic, according to the CDC. There are two main ways of transmitting the parechovirus: the respiratory route (like coughing or sneezing) and the oral-fecal route. The latter is a more common way young kids spread viruses, as invisible bacteria or viruses from one child’s stool makes it into the mouth of someone else.

The parechovirus is more common in summer and fall.

In the warning issued last week, the CDC urges doctors and health care providers to test for parechovirus if an infant has an unexplained fever, sepsis-like syndrome, or neurological problems like seizure and meningitis.

“Since May 2022, CDC has received reports from healthcare providers in multiple states of PeV infections in neonates and young infants,” the agency wrote. It did not specify how many states or which states the virus has been found in.

One state where the virus has been confirmed is Connecticut, where it took the life of 34-day-old Ronan DeLancy. At 10 days old, “his parents noticed he was fussy, appeared tired, stopped feeding and had a rash,” according to Hartford HealthCare, but his pediatrician said Ronan was probably just colicky.

“Still concerned, the DeLancys brought Ronan to the hospital. His oxygen levels dropped rapidly and he began to have seizures. An MRI showed brain damage and testing revealed that he had parechovirus,” Hartford HealthCare wrote in a post warning of the dangers of the virus.

“Over the last five years, we’ve begun to realize that through mutations and more virulent subtypes, these viruses, particularly parechovirus, can be fatal,” said Andrew Wong, MD, a primary care provider the hospital group. If not fatal, it can cause lifelong debilities such as neuromuscular weakness and developmental delays.” The CDC says those types of long-term neurological issues are rare.

“There is no specific treatment for PeV infection,” the CDC adds in its warning. “However, diagnosing PeV in infants might change management strategies and provide important health information for families.”