Gastrointestinal Illness Transmission Mechanisms

On the second day of cruising on the Carnival Legend in 2003, I was standing in a crowded hallway with about 200 other people waiting for the restraurant doors to open for the first dinner sitting. The hallway was about 15 to 20 feet wide, so there was plenty of room for the people waiting for their meal.

After 10 minutes, I realized there was a man several rows behind me with a persistant cough and he was not covering his mouth. With the excitement of eating in the formal dining room, I quickly forgot about the cough and I continued speaking with the person traveling with me. I realized there was nowhere to go to get away from his coughing so the only thing I could do is hold my breathe for as long as humanly possible.

But, after sitting down, the deep, throaty sounds of the man coughing were still echoing in my mind. Thinking to myself, "what could have been the reason for his coughing: was it a simple cold virus or something more contagious? Does this mean the rest of my cruise will be filled with diarrhea and vomiting?"

Unlike twenty years ago, the man's cough could not easily be forgotten or unnoticed. The sputnum spewn forth from this man may or may not be infectious but always a good idea to remember these situations just in case one gets sick a few days later.

Cruise ships are the perfect incubator for gastrointestinal disease. After exposure to 10-100 virus particles, it takes between 12-48 hours for the symptoms to manifest themselves and another several days before the virus runs its course through the body. But, beware, the body still sheds infectious virus particles for at least several days after the illness seems to be gone.

Simply stated, direct contact spread; of germs requires a person to touch another person in some way such as shaking of hands or kissing. This direct physical contact allows germs to move from one person to the next.

Viruses are hearty germs as they have the ability to continue living on surfaces that a sick person has touched for hours, and sometimes, days. When a virus germ is spread via an inanimate object, such as a doorknob or shared pen, it is called indirect contact spread.

Contact Spread of infectious virus germs can be accomplished by food contaminated by sick workers, by airborne dispersion of cough or vomit droplets (like the person coughing in a crowded food line), contaminated water in ice makers, handrails in ship hallways, workout equipment, pool lounge chairs, utensils in the cafeterias, toilets, matresses, rugs, and even the seats people sit on.

Philip Tierno, a self-proclaimed germ hunter, states that up to 80% of all infections from the common cold to venerial diseases are transmitted by people touching one another or touching objects that others have touched. Common cold, flu and stomach viruses, for example, can live on fingertips for house, and they can survive on the surfaces of objects for days.

Given the nature of gastrointestinal viruses, it's suprising there aren't more outbreaks of disease on cruise ships, in nursing homes, in schools and at the workplace. After tracking gastrointestinal disease over 15,000+ cruises, it becomes obvious that it never really goes away and almost always exists on the cruise ships, and in rare instances goes over the arbitrary 3% threshold set by the CDC.

If you have ever been close to a person that sneezed or coughed, you may have felt tiny droplets on your exposed skin, most often your face, arms or hands. Most often, the person feeling the spray is less than 3 or 4 feet away and may become contaminated with virus particles if these particles find their way into the recipient's mouth, nose, or eyes. Airborne transmission is a common mechanism for passing pneumonia, flu and common cold in confined areas.

Remembering that viruses are hearty germs and can live on surfaces for hours and even days without a human host--it has been documented that vacumning a rug can once again make infectious germs airborne infecting anyone that comes in contact with those germs. So, it's possible for a person to become infected via airborne germs without being in the immediate vicinity of the person who by sneezed or coughed.

When dealing with cruise ships, the CDC places the major emphasis on foodborne and waterborne contamination issues that can potentially affect hundreds of passengers and crew through a single incident. Common vehicles might include a contaminated lot of meat, fish, shellfish including shrimp, vegetables including lettice, fruit and even drinking water. The food may become contaminated at it's source before arriving onboard the ship, contaminated during preparation by the ship's crew, or even by an infected passenger that has contact with the food during a onboard party.