The term contagious in the medical context refers to a disease that can be transmitted from one person to another, or even from an animal or insect to a human. Infectious diseases may or may not be contagious depending on whether the infectious agent, such as viruses, bacteria or protozoa, can be easily transmitted between people. Therefore diarrhea caused by infections may or may not be contagious, depending on the cause.
Contagious Type of Diarrhea
Most cases of acute diarrhea are due to infections and specifically viral infections. This type of viral diarrhea is commonly referred to as the ‘stomach flu’. Most of the time this viral diarrhea is highly contagious and easily spread from one person to another, particularly among children. Less often bacteria or protozoa (single-celled microbes) may also cause diarrhea, either directly or due to the action of their toxins.
Infectious diarrhea due to bacterial or parasitic food poisoning or due to rotavirus infection can be transmitted by stool-to-mouth (fecal-oral) route (with hands, water, food, toys and other objects contaminated with the stool). Additionally, viral diarrhea can be contracted by droplet infection, that is by inhaling droplets of nasal secretions or saliva of an infected and sneezing or coughing patient (usually small child).
Diarrhea is not likely to be transmitted by inhaling the odor of diarrheal stool. Diarrhea due to bacterium Clostridium dificcile or yeast Candida albicans overgrowth is not likely contracted by a healthy person, but it can be contracted by someone with lowered immunity (a person with AIDS, or a patient after antibiotic treatment, during or after chemotherapy, and so on).
Diarrhea in most of other disorders (IBS, food allergies, liver, gallbladder, pancreas disease, celiac disease, lactose intolerance, Crohn’s disease) is not usually contagious, unless the affected person develops a subsequent infection that causes diarrhea and can be easily spread to other people.
Prevention of Diarrhea
As with any disease, prevention is always the better option. This is not always possible as infectious diarrhea can be spread even without coming into direct contact with an infected person. For example, door knobs may contain dried secretions that are infectious and not visible to the naked eye. Another person who touchs the same doorknob and the their mouth can become infected.
However, the following dietary and lifestyle measures may be helpful in preventing diarrhea. It should be practiced at all times but particularly during periods of outbreaks. In some instances antibiotics or even antiviral substances may be prescribed for a high risk person who is likely to have come into contact with an infectious agent that may lead to severe and possibly life-threatening diarrhea. Vaccines are another effective way of preventing certain types of infectious diarrhea.
- Washing hands after every contact with the stool (toilet, soil, animals).
- Cleaning surfaces, contaminated with stool, soil, chemicals.
- Preferably use an antiseptic soap or handwash to clean the hands, especially before eating.
- Keeping small children out of day care centers, if they have diarrhea or if other children at the center have it, can be useful in preventing and avoiding outbreaks.
2. Food Preparation
- Using clean utensils and sterile boards or other surfaces for cutting meat and raw vegetables.
- Boiling unpasteurized milk and cooking meat fully.
- Serving or cooling foods immediately after cooking.
- Cooking with clean water that has been sterilized appropriately.
3. Disinfection of Drinking Water
Diarrhea is the number one cause of death among children due to dehydration. In developing nations, contaminated water is one of the leading ways in which the infectious agents that cause this diarrhea is spread.
- Chlorine tablets (calcium hypochlorite) for the “point-of-use” disinfection
- Iodine disinfection (does not kill parasite Cryptosporidium<)
- Water filters with label ‘reverse osmosis’ and pores smaller than 1 micron, may protect against all microbes, but they are expensive and easily plugged with particles of dirt. Cheaper filters should be used in combination with chemical disinfection or boiling (1)
- Chlorine bleach (sodium hypochloritehttps://www.healthhype.com/rotavirus-diarrhea-children-causes-symptoms-treatment.html) for wells, pools, water supplies.
- Bottled water from reputable manufacturers should be the only option for travelers to countries where there is a risk of contaminated water.
Antibiotics are not generally recommended as a prevention of diarrhea, because of their many side effects and possible development of bacterial resistance. They can be prescribed to people with lowered immunity, or for important travel for the short term use (they are effective in most cases). Pepto-Bismol, 4 times a day (with meals and in the evening), may prevent bacterial diarrhea in some cases (2). The drug should not be taken more than 3 weeks in a row.
Rotavirus vaccine Rotateq (in US and Canada or Rotarix (in Europe) is recommended for children under 5 years of age (routinely performed together with other vaccines in infants). Vaccinations have no known serious side effects, and they are effective in over 70% of cases.
Measles + Mumps + Rubella + Varicella (MMRV), Hepatitis A, and Typhoid vaccine are recommended for children older than one year, before travel to risky countries. Yellow fever vaccine is required for a travel to some African and South American countries.
Vaccination of Animals:
- Salmonella vaccine for poultry (3);
- E. coli 0157:H7 vaccine for cattle; available in Canada (4);
- Entamoeba histolytica vaccine for cattle (5).
6. Foods to Stop Diarrhea
When diarrhea has already started, there is no special diet to stop it. All foods from BRAT diet (Bananas, Rice, Apple sauce, Toast) are appropriate in most cases of acute diarrhea, but other foods may be also fine. An usual diet is recommended – one should eat as he/she feels comfortable, unless a certain food was recognized as a cause of diarrhea. Heavy sugary or fatty foods should be avoided in all cases of diarrhea, though.
A person with diarrhea should replace lost fluid, so regular drinking is a must. Drinks, sweetened with sorbitol or HFCS, or large amounts of fruit juices can cause loose stools even in healthy persons, so they should be avoided in diarrhea. Plain water or, in heavy diarrhea, rehydration solutions, like Rehydralyte, are appropriate.