Norovirus or Food Poisoning? Is there Really a Difference?
News of outbreaks of the norovirus are all over the news this holiday season. Reports of outbreaks of the norovirus continue to make headlines with stories of the contagious virus infecting many, being especially prevalent in schools, nursing homes and on cruises (small, highly-populated, closed systems). The latest incidence being reported comes from Grand Junction, Colorado where the entire Mesa County Valley school district was closed due to the high number of reported illnesses connected to the norovirus. A similar story comes out of Albany, Oregon where the school district shut their doors before the Thanksgiving break to disinfect the schools after a high number of norovirus illnesses were reported.
So, with the highly contagious norovirus on the rise this winter, as well as the risk of food poisoning with the high number of tainted, recalled foods recently, how can one tell the difference between these two illnesses?
The short answer is you cannot – because there is, fundamentally, little difference.
First of all, The Centers for Disease Control and Prevention (CDC) describes the norovirus as a contagious stomach virus or viral gastroenteritis with the most common strain found which is the norovirus. The norovirus can be transmitted through either direct contact with an infected person or indirect contact with contaminated surfaces, and this can include eating food contaminated with norovirus or eating food with hands contaminated with norovirus. Food poisoning is the result of ingesting contaminated food wherein the bacteria or other contaminate, such as food poisoning from Hepatitis A, enters the body causing similar gastroenteritis symptoms or other symptoms (some, like food poisoning from ciguatoxin and food poisoning from botulism have neurological symptoms).
Symptoms for both direct food poisoning (such as food poisoning from Salmonella or food poisoning from Shigella) and the norovirus are very similar which can make it difficult to determine the difference – if there is any. The most common symptoms which are shared between both diseases are diarrhea, nausea, vomiting, stomach cramping and a low-grade fever. However, there are a few symptoms that are typically found more often with one or the other. For instance, with the norovirus other symptoms listed are a loss of appetite and headaches, while with food poisoning symptoms also include bloody stools, chills and body aches.
The best way to determine the exact etiology of the gastrointestinal illness, or whether a person had contracted a stomach virus or bacterial food poisoning is to seek medical attention. Some of the clues a health professional uses can include onset of illness. With the norovirus, symptoms tend to start 12 to 48 hours after contracting the virus. In some cases, such as food poisoning from staphylococcus bacteria, the symptoms can start in as little as 30 minutes. Other forms of food poisoning can lie dormant for weeks (such as Cyclospora or Hepatitis A). But in reality, the only way to correctly diagnose the ailment is to seek a health professional who will obtain a proper sample (usually stool) for testing. A stool culture will test for most common bacteria, such as E. coli, Shigella, or Salmonella. A more precise and specific test is necessary for Cyclospora, norovirus (often, only the health department performs this in the aftermath of a suspected outbreak), and blood tests are often necessary for Hepatitis A. For Listeria, often a cerebral spinal tap culture is required!
The best option, aside form requesting a stool culture, is to report any alleged or suspected case of food poisoning or stomach bug (as norovirus is often called) to the local health agency. This will help identify outbreaks and let the health agency step in and make sure proper testing is being performed.
The most important this to remember if the norovirus is highly contagious and it is crucial to practice good hand washing hygiene. Handling food safely is especially true during the holiday season when people are serving large numbers of guests.
