Norovirus hospitalizes thousands of Canadians annually

Most people get over a bout of norovirus relatively quickly and without a visit to a health care provider. In extreme cases, a couple of days worth of vomit and painful stomach cramps can send folks to the hospital, especially if they become severely dehydrated.

Our hoser colleagues have estimated that between 4000 and 11,000 people are hospitalized as a result of Norovirus annually in Canada, resulting in a cost burden of over $21 million CAD (or about 5 million Timbits).images

Estimated hospitalizations attributed to norovirus and rotavirus infection in Canada, 2006–2010
V.K. Morton, M.K. Thomas and S. A McEwen
Epidemiology and Infection / Volume 143 / Issue 16 / December 2015, pp 3528-3537

Enteric viruses including norovirus and rotavirus are leading causes of gastroenteritis in Canada. However, only a small number of clinical cases are actually tested for these pathogens leading to systematic underestimation of attributed hospitalizations in administrative databases. The objective of this analysis was to estimate the number of hospitalizations due to norovirus and rotavirus in Canada. Hospitalization records for acute gastroenteritis-associated discharges at all acute-care hospitals in Canada between 2006 and 2011 were analysed. Cause-unspecified gastroenteritis hospitalizations were modelled using age-specific negative binomial models with cause-specified gastroenteritis admissions as predictors. The coefficients from the models were used to estimate the number of norovirus and rotavirus admissions. The total annual hospitalizations for rotavirus were estimated to be between 4500 and 10 000. Total annual hospitalizations for norovirus were estimated to be between 4000 and 11 000. The mean total annual cost associated with these hospitalizations was estimated to be at least $16 million for rotavirus and $21 million for norovirus (all figures in Canadian dollars). This study is the first comprehensive analysis of norovirus and rotavirus hospitalizations in Canada. These estimates provide a more complete assessment of the burden and economic costs of these pathogens to the Canadian healthcare system.

The quasi-daily probe E1: The okra of the sea

My friend Mike Batz of University of Florida’s Emerging Pathogen Institute and I were chatting a while back and thought it would be cool to connect for short podcasts when there was something fun going on. Here’s the first episode (and maybe the last) in it’s raw, unedited, short format.Daily-probe

Today we talked about oysters, raw and steamed, Vibrio, norovirus, burden and risk-based messaging.

The article that prompted the probe was from Lifezette where oysters are referred to as those scary shellfish.

Heads up, raw oyster lovers. New research from China shows the bivalves not only transmit human norovirus, they also serve as a reservoir for the harmful and highly contagious virus.

In an expansive study published recently in Applied and Environmental Microbiology, a journal of the American Society for Microbiology, scientists discovered that more than 80 percent of the known noroviruses matched those found in oysters.

Even common recommendations for reducing the risks of illness, such as avoiding them from warm-water sources, aren’t a guarantee you won’t get sick, food safety expert Ben Chapman told LifeZette.

“Considering where they’re from, and not eating them at a certain time of year, may reduce the risk, though risk is always there,” said Chapman, a researcher at North Carolina State University. Chapman also notes that cooking oysters may lower risk, but that steaming — a popular way to prepare them — isn’t likely to get them above 140 degrees.

Listen to the episode here.

The burden of foodborne illness: it’s kind of a big deal

Last week I gave a guest lecture to an undergraduate nutrition class at UNC-Chapel Hill on the burden of foodborne illness as sort of an introduction to how and why folks like small farmers, school garden managers, cafeteria staff address food safety.

In a lot of my talks I get looks of bewilderment when I throw up the details from Elaine Scallan (and lots of her colleagues) papers on the burden of foodborne illness. Same with when I show economic estimates from friend of barfblog and all-around-good-guy-with-hipster-glasses Mike Batz (and colleagues). Foodborne illness, is kind of a big deal (at least to us food safety nerds).

I’m collaborating with Matt Shipman, public information officer at NC State University and curator of The Abstract, on a set of food safety-related posts from other NCSU folks as we roll toward WHO’s World Health Day – which is focused this year on food safety.

Here’s the first post:21d2f2194e7eb6925dac5a428cc518d4398b850316887505b740e8bd0e8ffdd2

Food safety poses a global health problem. According to the World Health Organization, contaminated food can cause more than 200 diseases – and food- and water-borne diseases that cause diarrhea are estimated to kill two million people each year worldwide.

And food safety is not just someone else’s problem.

“Foodborne illnesses are a significant problem in the United States, with massive impacts on public health and the economy,” says Ben Chapman, a food safety expert and researcher at NC State. And the numbers back Chapman up.

According to a 2012 report from researchers at the Emerging Pathogens Institute, Resources For the Future, and the U.S. Department of Agriculture’s Economic Research Service, foodborne illness is estimated to cost the U.S. more than $14 billion annually. (The estimate takes into account factors such as medical costs and productivity losses.)

And a 2011 report from the U.S. Centers for Disease Control and Prevention (CDC) reported an estimated 9.4 million episodes of foodborne illness each year in the U.S. from known pathogens. An additional 38.4 million cases are estimated to come from unspecified or unknown pathogens. In total, foodborne illnesses are thought to contribute to 48 million illnesses annually – resulting in more than 128,000 hospitalizations and 3,000 deaths.

It is, in short, a big deal.

So what are these foodborne illnesses? And how much damage does each of them cause?

In advance of World Health Day, we wanted to explain a handful of the relevant pathogens implicated in foodborne illness.

Campylobacter: Campylobacteris a genus of bacteria, many of which can cause an illness called campylobacteriosis in humans, with symptoms including diarrhea and abdominal pain. People can contract campylobacteriosis from undercooked chicken, from cross-contamination via raw chicken, or from drinking unpasteurized milk.

According to the 2012 paper, campylobacteriosis affects 845,000 people annually in the U.S., costing the nation an estimated $1.747 billion every year and leading to 8,463 hospitalizations.

Listeria monocytogenes: This is a bacterium that causes listeriosis, which is characterized by fever, muscle aches, and sometimes by gastrointestinal problems, such as diarrhea. Listeriosis can be contracted from an incredibly broad range of foods.

According to the 2012 study, listeriosis costs the U.S. $2.577 billion annually, despite the fact that there are only 1,591 illnesses per year. But 1,455 of those illnesses require hospitalization – and 255 result in death.

Norovirus: Noroviruses are the most common cause of foodborne illness in the U.S., affecting an estimated 19-21 million people each year. Symptoms range from vomiting and diarrhea to fever and headache. Transmission comes from ingesting infected feces or vomit particles – for example, by touching a contaminated surface and then touching food or touching your mouth.

According to the 2012 study, noroviruses cost the U.S. $2 billion per year, with more than 14,000 hospitalizations and approximately 150 deaths annually. NC State is a leader in norovirus research, and home to NoroCORE – the Norovirus Collaborative for Outreach, Research, and Education. NoroCORE pulls together norovirus research from 18 institutions, with funding from the U.S. Department of Agriculture.

Salmonella enterica: This is one species of the pathogen that has myriad of subspecies and types – more than 1,400 of which are known to cause human illness. Infection with Salmonella species causes salmonellosis, with symptoms including diarrhea, fever, and cramping. Salmonellosis can be contracted from a variety of sources, ranging from poultry to peanut butter to mangoes.

According to the 2012 study, the subspecies within S. entericaalone costs the U.S. $3.3 billion each year, causing more than one million hospitalizations and almost 400 deaths annually.

What are researchers doing about this?

The four pathogens listed above are just a few of the rogue’s gallery of bacteria and viruses that can cause foodborne illness. But researchers are constantly learning more about these health risks.

“New technology and new research on pathogens, practices and prevention are improving our ability to identify and address foodborne illness,” Chapman says. “The field is really opening up. It’s an exciting time to be involved in food safety research.”

Between now and April 7, we’re planning to publish a series of posts on various aspects of food safety – what we know, what we don’t know, and what we’re working on. We also hope to offer insights to help folks lower the risk of contracting foodborne illnesses. We hope you’ll learn something new.

Note: you can find all of our posts related to food safety here.

Citations:

Batz, Michael B., Sandra Hoffmann, and J. Glenn Morris, Jr. “Ranking the Disease Burden of 14 Pathogens in Food Sources in the United States Using Attribution Data from Outbreak Investigations and Expert Elicitation” Journal of Food Protection, Vol. 75, No. 7, 2012, Pages 1278–1291. doi:10.4315/0362-028X.JFP-11-418

Scallan, Elaine, et al. “Foodborne Illness Acquired in the United States—Major Pathogens” Emerg Infect Dis, Vol. 17, No. 1, 2011. doi:10.3201/eid1701.P11101