Doctors at Norton Children's Hospital in Louisville are seeing a rise in cases of respiratory syncytial virus or RSV.

Health officials say nearly all children are infected before the age of two and some more than once.

Still, it's not clear if this season will be worse than last year.

Doctors from the hospital spoke with reporters today about what parents should look out for if their little one is sick.

Historically, our RSV has been the most common reason for hospitalization.

Not the most common infectious cause for hospitalization in young kids.

But RSV is the most common cause of hospitalization in kids under five years of age.

This year's RSV season looks a bit different than last year's.

Last year, we saw the majority of RSV cases in October and November.

And by this point in the year, cases had started to trend down.

The worst of RSV season was over.

Now, what's happening this year, we started to see cases begin to tick up in late August or early September, but we didn't really see a big spike in cases until this month.

And cases are still going up.

Last week, within all of Norton Health Care, we had a record number of kids test positive for RSV.

This viruses does have a whole range of symptoms that somebody could present with.

It can range from just a little bit of a nose and a cough all the way into something that we call bronchiolitis, where the child has increased amount of mucus production, especially in the lower airways and a little bit of inflammation causing those what we would call respiratory distress.

The biggest things that I warn parents and to watch out for would be that work of breathing that your child is experiencing.

Are they breathing faster?

Are they using their belly?

You will see a child who has maybe a severe case of RSV using those extra muscles to breathe, but might be sucking in on the ribs.

In real severe cases, children may even be grunting or using nasal flaring in what we call or their noses.

They're trying to get more air in.