Perspective

Norovirus outbreak grows to 2,800 cases in northern California schools

Health officials from Yolo County in northern California have reported an outbreak of norovirus in the county schools with 2,836 cases among students and faculty.

During a press conference on May 12, the Yolo County Health and Human Services Agency reported a total of 952 cases of gastrointestinal illness — including stomach cramps, vomiting and diarrhea — among 32 schools in Yolo County; within 5 days, the number of cases had more than doubled to 2,091.

“The number of sick people is increasing every day at a very alarming rate,” Yolo County Public Information officer, Beth Gabor, said in a press release. “The outbreak has been identified and confirmed by specimen testing to be norovirus which is highly contagious. Any vomit or diarrhea may contain norovirus and should be treated as though it does.”

While there are currently no plans to close the affected schools, Yolo County Public Health officer, Ron Chapman, MD, MPH, advised parents and school staff that any students presenting with symptoms should remain at home until symptoms have subsided, if not longer. “Stay home for an additional 48 hours after symptoms are gone. Even though you feel better, you still carry the virus and can infect others.”

In neighboring Sacramento County, health officials have reported six school districts with suspected cases of norovirus, including Elk Grove, Natomas, Sacramento City, San Juan, and Twin Rivers, as well as the Elverta Joint Elementary School District where school officials closed three schools early in May due to 53 cases of norovirus among students and faculty. It remains unknown whether there is a connection between these new cases and the ongoing outbreak in Yolo County.

According to the CDC, norovirus is responsible for 1.7-1.9 million outpatient visits and 400,000 ED visits annually, primarily in young children, as well as 570-800 deaths, which disproportionately impacts young children and the elderly. Many people develop norovirus in cooler months, particularly from November to April, and can develop the infection five times during their lifetime.by Bob Stott

Health officials from Yolo County in northern California have reported an outbreak of norovirus in the county schools with 2,836 cases among students and faculty.

During a press conference on May 12, the Yolo County Health and Human Services Agency reported a total of 952 cases of gastrointestinal illness — including stomach cramps, vomiting and diarrhea — among 32 schools in Yolo County; within 5 days, the number of cases had more than doubled to 2,091.

“The number of sick people is increasing every day at a very alarming rate,” Yolo County Public Information officer, Beth Gabor, said in a press release. “The outbreak has been identified and confirmed by specimen testing to be norovirus which is highly contagious. Any vomit or diarrhea may contain norovirus and should be treated as though it does.”

While there are currently no plans to close the affected schools, Yolo County Public Health officer, Ron Chapman, MD, MPH, advised parents and school staff that any students presenting with symptoms should remain at home until symptoms have subsided, if not longer. “Stay home for an additional 48 hours after symptoms are gone. Even though you feel better, you still carry the virus and can infect others.”

In neighboring Sacramento County, health officials have reported six school districts with suspected cases of norovirus, including Elk Grove, Natomas, Sacramento City, San Juan, and Twin Rivers, as well as the Elverta Joint Elementary School District where school officials closed three schools early in May due to 53 cases of norovirus among students and faculty. It remains unknown whether there is a connection between these new cases and the ongoing outbreak in Yolo County.

According to the CDC, norovirus is responsible for 1.7-1.9 million outpatient visits and 400,000 ED visits annually, primarily in young children, as well as 570-800 deaths, which disproportionately impacts young children and the elderly. Many people develop norovirus in cooler months, particularly from November to April, and can develop the infection five times during their lifetime.by Bob Stott

    Perspective

    William T. Gerson

    Norovirus is the most common viral etiology in epidemic gastroenteritis worldwide and, since the introduction of the rotavirus vaccine, it is the most common cause of gastroenteritis in adults and children in the United States. In pediatric offices, we can help identify noroviral infection since it is distinctly characterized by occurrence in outbreaks with short incubation times (24-48 hours), abrupt onset, a majority of affected cases with vomiting, and an average duration of illness of 12-60 hours. Public health colleagues should be involved early in the investigation of these situations and to add their particular expertise in epidemic management and control.

    General pediatricians are likely to be involved in many – if not all – aspects of a norovirus outbreak. Closing a school dramatically affects a community: While ensuring the well-being of students and staff, closures can confuse, disrupt, alienate, and in some ways, increase anxiety over school safety if not done in a professional and compassionate manner. Attention to issues of health information privacy is required. Resource allocation to school districts and best practice implementation for classrooms, health offices and cafeterias are also critical. It is humbling to remember that proper hand washing, though critical in halting the spread of many diseases, is very difficult to achieve, particularly in most school settings.

    Prevention is challenging as limiting exposure to infected persons in the community setting is extremely difficult given asymptomatic transmission particularly in children: the difficulties involved in assuring good handwashing (soap and water, as alcohol-based hand sanitizers have little effect on norovirus); the association with food services (a universal feature of schools), and; the fact that norovirus is extremely stable in the environment, able to resist freezing and heating as well as disinfection with alcohol or standard cleaning agents. Transmission also requires a small inoculum size (<100 particles) thus making outbreak control even more arduous.

    • William T. Gerson, MD
    • Clinical professor of pediatrics
      University of Vermont College of Medicine

    Disclosures: Gerson reports no relevant financial disclosures.