Pesticide Made With Contaminated Water May Spread Norovirus

A new study suggest that farmers that mix pesticides with contaminated water from wells, irrigation ditches, rivers and lakes, all known to harbor norovirus, may be the source of reinfection. The greatest risk from pesticide-born norovirus would appear to be for produce such as raspberries, strawberries and lettuce.  These fruits are frequently sprayed shortly before harvest, then consumed raw.  Washing the produce can reduce the risk of norovirus but does not completely eliminate it.

Although cases of norovirus illness are epidemiologically linked to produce, “we do not have a full understanding of how norovirus enters the food chain,” says Kali Kniel, an associate professor of food parasitology and virology at the University of Delaware in Newark. She says the discovery that norovirus survives in pesticides is important, given water scarcities and the resulting increased reuse of water for application of pesticides and fertilizers.

Norovirus is a resilient virus, even heating food may not be enough to kill the virus.  Norovirus has been known to survive heating up to 140 degrees F and it can survive being frozen.

Signs and Symptoms of Norovirus

Often referred to as the stomach flu, norovirus causes diarrhea, abdominal pain and vomiting usually within 24-48 hours of exposure. The symptoms of norovirus can be debilitating with those at highest risk being infants, the elderly and those with compromised immune system.

How Contagious is Norovirus?

The virus is highly contagious with known infected persons shedding billions of norovirus particles, though it takes only 18 of these particles to infect another person.  Thus those that reside or spend time in close proximity to others such as in day care or nursing homes are often are the hardest hit when an outbreak occurs.

Not only can the virus spread before a person actually feels ill, but the virus can continue to be shed from an infected persons body via the stool for up to 2 weeks after symptoms of illness have resolved.