Shigellosis Infection - How you Can Get it and How Common is it


Shigellosis is an infection of the colon or large intestine caused by a group of bacteria known as shigella. While some people may not display any symptoms at all, in most cases the infection leads to vomiting, abdominal cramps and especially diarrhea which may even contain blood and pus. All these signs may or may not be accompanied by fever. Since the shigella bacteria attack the lining of the intestine, it leads to inflammation and ulcers which in turn result in bleeding and blood in the stool of the infected person.

Shigellosis is transmitted through the fecal to oral route. This means that the bacteria is present in the feces of the infected person and when someone eats or drinks products contaminated with the feces of the infected person, the bacteria finds a way to enters a new body. The Shigella bacteria remain present in the diarrheal stools of infected persons not only while they are sick but for up to a week or two afterwards. Some of the ways in which you can contract Shigellosis are:

  1. If you eat or drink anything that is contaminated with the feces of someone already infected with Shigella bacteria.
  2. If you eat food or drink beverages that have been prepared by a person whose hands are contaminated with the bacteria.
  3. You can also get it if your own hands are contaminated by feces, such as after changing a diaper, and then you eat with your hands or put your hands in your mouth.
  4. Sometimes you can get shigellosis by drinking water that has been contaminated due to sewage overflows, sewage systems that are not working properly and polluted storm water runoff. Wells may be more vulnerable to such contamination after flooding, particularly if the wells are shallow, have been dug or bored, or have been submerged by floodwater for long periods of time.
  5. If you use a swimming pool that is contaminated with the feces of a person with shigellosis.
  6. Other places which can contain contaminated water are splash tables, untreated wading pools, or shallow play fountains of the kind used by daycare centers. Shigella infections can then be acquired by drinking, swimming in, or playing with the contaminated water in these places.
  7. among young kids, shigellosis is most commonly spread because they do not remember to wash their hands properly after using the toilet. Family members, siblings and playmates of such children are at high risk of becoming infected.
  8. Vegetables growing in areas where sewage water has seeped can also be contaminated with the Shigella bacteria which can in turn be transmitted to the person who eats them.
  9. Also flies breeding in infected feces can eventually contaminate open food items and thus infect the person who eats them.
  10. According to the factsheet on Shigellosis published on the Centers for Disease Control and Prevention website 1, ooutbreaks of shigellosis have been known to occur among men who have sex with men. This is probably because they are exposed to the bacteria when engaging in anal or oral sex.
  11. You cannot contract Shigellosis if an infected person coughs or sneezes before you since these bacteria is not transmitted through the respiratory route. The infection is not even transmitted through touch per se, but if the infected person’s hands are contaminated with their feces and later you put the part of your body, like fingers, he/she touched into your mouth, you stand a risk of acquiring the infection.
  12. The best way to prevent a Shigellosis infection is to practice regular and thorough hand-washing, preferably with germicidal soaps. This breaks the cycle of the fecal to oral route and ensures that whatever is going into your mouth is bacteria-free. It is especially important to wash hands before eating, after using the toilet, before preparing food and feeding others.

The Centers for Disease Control and Prevention estimates that around 14,000 cases of shigellosis are reported every year. however since shigellosis does not always present major symptoms, it is quite possibly that many cases of the infection go unreported and the actual number of infections in the country may be at least twenty times higher. Shigellosis is more common in summer when the heat and humidity weakens the immunity of the body, breeds more flies and flying insects as well as presents more options for people to use swimming pools, fountains and other places which are likely to hold contaminated water. Also the infection is more common in areas where low standards of hygiene are practiced. When shigella bacteria contaminate water supplies through faulty sewage, sometimes entire communities can be affected by the infection. Children, especially toddlers aged between two and four are the most likely to get shigellosis because they are still not properly toilet-trained. Many cases are related to the spread of illness in child-care settings while some are the result of the spread of the illness in families with more than one small child.

In developing countries however shigellosis is much more common due to faulty sewage systems, contaminated water pipe lines and also lack of awareness of hygienic practices such as hand-washing. Also infections in these societies are far more likely to become severe or complication because of lack of widespread healthcare facilities and awareness regarding the symptoms.

What makes shigellosis so common is not only the fact that the fecal-oral route is one of the easiest to spread through but also the fact that the disease is not caused by a single type of bacteria. The Shigella germ is actually a family of bacteria that can cause diarrhea in humans and there are several different kinds of Shigella bacteria. For instance the Shigella sonnei, also known as "Group D" Shigella, accounts for over two-thirds of shigellosis in the United States, according to information on the CDC website. Shigella flexneri or "group B" Shigella, accounts for almost all the rest of the shigellosis infections in the country.


National Center for Emerging and Zoonotic Infectious Diseases - Shigellosis