Chicago health officials are monitoring the outbreak of norovirus cases. What you need to know.

CHICAGO (CBS) — Cases of norovirus, a highly contagious stomach virus, are on the rise in the Chicago area and nationwide, according to the United States Centers for Disease Control and Prevention.

What does an explosion look like in the Chicago area and what can you do to keep your family safe?

Cook County is tracking its highest number of norovirus cases in more than three years, and the county’s top doctor said many cases are going unreported.

“We really want to take care of these types of viruses, because they are highly contagious and cause many diseases,” said Dr. Rachel Rubin, chief medical officer for the Cook County Department of Public Health. “During the holidays because people go out and celebrate. They get together with other people. That makes publicity a lot easier to happen.”

CBS News Chicago asked health professionals what you need to know as we evaluate this increase.

“[The outbreak] it may take several months or more. It could actually last into the spring,” Rubin said. “Why it’s higher now compared to two or three years ago, nobody really knows.”

Dr. Sameer Vohra, director of the Illinois Department of Public Health, said norovirus cases are increasing statewide.

“For many, it’s a very unpleasant GI (gastrointestinal) disease,” he said.

Vohra said the main symptoms of norovirus to look out for are diarrhea, vomiting and nausea — usually occurring 12-48 hours after exposure. He said most people recover within one to three days, but rare cases require hospitalization.

What can you do to stay safe from norovirus?

Experts say the most important thing is to wash your hands regularly. You should also cook any shellfish before eating, wash fruits and vegetables before eating, and clean any contaminated areas with bleach.

“Norovirus can live on water for a long time,” Rubin said.

Another suggestion? It goes away on its own a few days after the symptoms stop.

“What’s unique about this bug is that you can spread it even a few days after you feel better,” Vohra said.

A spokesperson for the Chicago Department of Public Health said they can test wastewater for norovirus if they believe there’s a public health need, but that’s not happening right now:

“Individual cases of norovirus are not reported to CDPH; only outbreaks are reported. However, norovirus is a highly contagious virus and is the leading cause of vomiting and diarrhea in the United States. Outbreaks are most common in November through April, although people can get sick from norovirus at any time of the year. Several small outbreaks of suspected norovirus have been reported in CDPH in December, but this is unusual for this time. Norovirus outbreaks are usually caused by a sick person spreading the virus through direct contact for outbreaks including health care facilities, restaurants and schools or childcare centers.

Common symptoms of norovirus are diarrhea, vomiting, and nausea that usually occur 12-48 hours after exposure to the virus. Most people get better within 1 to 3 days, but young children under 5, older adults, and people with weakened immune systems are at risk. have a severe infection. The best ways to prevent norovirus are to wash your hands thoroughly with soap and water, cook shellfish properly, wash fruits and vegetables, clean and disinfect with bleach after a person has vomited or is sick. diarrhea, and stay home for 2 days after your symptoms stop.

As for wastewater testing, we do not currently screen for norovirus, but we have the ability to do so, should we believe there is a public health need – currently, norovirus reports are not accompanied by what we expect to see. during the winter.

When children return to school after the holidays during this norovirus outbreak, parents can find more information about the disease on the CDC website.