A common nuisance of wandering the world is travelers' diarrhea. Food in many regions of the world isn't always properly handled, and that can put you in bed for several days.
Countries with strict (and regularly enforced) food safety regulations, like the U.S., still experience occasional, high-profile outbreaks of foodborne diseases. This fall, hundreds of unlucky diners at Chipotle restaurants around the country fell prey to outbreaks of E. coli and norovirus.
But foodborne illness cases here in the U.S. are few compared with countries in sub-Saharan Africa and Southeast Asia, where the disease burden of contaminated food is most severe, according to a new report released by the World Health Organization.
The study authors say that about 10 percent of the world's population gets ill from bad food every year, and many of the cases are in those regions. The report provides the first estimates of the death, disease and disability from foodborne illnesses around the world caused by some 31 bacteria, viruses, parasites, toxins and chemicals.
The WHO report measured illnesses from pathogens like E. coli to chemical toxins like dioxin or aflatoxin, a fungal toxin that can accumulate on corn and nuts.
"If you added together all of the illness suffered and the time lost [from foodborne illness], it's an annual loss of 33 million years of healthy life," says Felicia Wu, food scientist at Michigan State University and one of the authors of the report. "As far as mortalities, we estimated as much as 420,000 lives lost." One-third of all cases were in children, who are most vulnerable to diarrheal diseases.
The most common foodborne ailment and associated burden worldwide is diarrhea caused by norovirus. And its burden — as calculated by number of productive years lost to a disease — in countries in sub-Saharan Africa is about 25 times worse than in countries in North America. Meanwhile, aflatoxin causes decades of productive life to be lost in Africa and Asia, but virtually none in North America.
The estimates have been nearly a decade in the making, involving hundreds of experts. It's the first step in finding ways to a global approach to reduce food-related illness, says Wu. "This is exactly the information we need to talk about cost-effective interventions around the world."
According to Craig Hedberg, an epidemiologist at the University of Minnesota who was not involved with the work, some countries may not realize how big a problem foodborne illness is. "This report may provide that spark that says these are real problems, and we really need to address what's going on," he says.
For example, countries where corn and nuts are commonly grown could help farmers learn to be more careful drying and harvesting their crop to reduce the aflatoxin-producing fungi. "It causes liver cancer, and the burden of disease caused by aflatoxin is very severe," Wu says.
In other cases, countries could invest in improved infrastructure like water sanitation, Hedberg says. Better water systems could reduce the transmission of waterborne pathogens like giardia or E. coli to food, and better roads could help get crops to market faster so they have less time to mold or rot.
These interventions could benefit consumers in other countries, too. Contaminated food from high-risk regions like South or Southeast Asia can spill over to nations around the globe. "There have been a number of outbreaks of imported foods into the U.S. contaminated by Salmonella," Hedberg says. "That represents a threat to a local economy as well as for consumers on this end of the [trade]."
What the report doesn't do is offer country-level data on foodborne illness for comparison. The researchers say that's because health surveillance systems differ a lot country to country, resulting in inconsistent data.
In general, estimates of death and disease from foodborne illness in individual countries are very uncertain, says Shannon Majowicz, an epidemiologist at the University of Waterloo who worked with WHO.
Even in countries with universal health care systems like Canada or Sweden, foodborne disease reporting can be inconsistent. "If we want to know how many people have Salmonella, we [count] the number of people who got sick, went to the doctor, collected a stool sample and got lab confirmation," Majowicz says. Few people who get sick after a meal will go through all of that trouble or seek medical help, and so many cases of illness from Salmonella and other pathogens may never be diagnosed or counted.
Still, Majowicz hopes the WHO report will spur countries to begin focusing on the problem. "This is really important to show why this issue that tends to fall off the radar is actually something worth investing in prevention," she says. After all, she says, foodborne illnesses technically are all preventable.
For more on how to avoid and prevent foodborne illness, read Michaeleen Doucleff's excellent primer over at Goats and Soda.