Waterborne Diseases

Shigellosisis is principally a disease of humans.Rarely occurs in animals, except other primates such as monkeys and chimpanzees.
Infants, the elderly, and the infirm are susceptible to the severest symptoms of disease, but all humans are susceptible to some degree. 
Shigellosis is a very common malady suffered by individuals with acquired immune deficiency syndrome (AIDS) and AIDS-related complex, as well as non-AIDS homosexual men

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The Shigella bacteria pass from one infected person to the next. Most Shigella infections are the result of the bacterium passing from stools or soiled fingers of one person to the mouth of another person.
Shigella infections can be acquired by drinking or swimming in contaminated water. Water may become contaminated if sewage runs into it, or if someone with shigellosis swims in it.The Shigella spp. are highly infectious agents that are transmitted by the fecal-oral route. 
Shigella infections may also be acquired from eating contaminated food. Contaminated food may look and smell normal. Food may become contaminated by infected food handlers who forget to wash their hands with soap after using the bathroom. Vegetables can become contaminated if they are harvested from a field with sewage in it. Flies can breed in infected feces and then contaminate food.
Shigella infections can also be acquired by swimming in contaminated water.
Although all Shigella spp. have been implicated in foodborne outbreaks at some time, S. sonnei is clearly the leading cause of shigellosis from food. The other species are more closely associated with contaminated water.
One in particular, S. flexneri, is now thought to be in large part sexually transmitted. 

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Most who are infected with Shigella develop diarrhea, fever, and stomach cramps starting a day or two after they are exposed to the bacterium. The diarrhea is often bloody. Shigellosis usually resolves in 5 to 7 days. In some persons, especially young children and the elderly, the diarrhea can be so severe that the patient needs to be hospitalized. A severe infection with high fever may also be associated with seizures in children less than 2 years old. Some persons who are infected may have no symptoms at all, but may still pass the Shigella bacteria to others.
Fatality may be as high as 10-15% with some strains. 
About 3% of persons who are infected with one type of Shigella, Shigella flexneri, will later develop pains in their joints, irritation of the eyes, and painful urination. This is called Reiter's syndrome. It can last for months or years, and can lead to chronic arthritis which is difficult to treat. Reiter's syndrome is caused by a reaction to Shigella infection that happens only in people who are genetically predisposed to it.
Once someone has had shigellosis, they are not likely to get infected with that specific type again for at least several years. However, they can still get infected with other types of Shigella.
The infective dose of Shigella spp is considered to be small: as few as 10 cells depending on age and condition of host.

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See your health care provider as soon as posible. 

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Shigellosis can usually be treated with antibiotics. The antibiotics commonly used for treatment are ampicillin, trimethoprim / sulfamethoxazole (also known as Bactrim* or Septra*), nalidixic acid, or ciprofloxacin. Appropriate treatment kills the Shigella bacteria that might be present in the patient's stools, and shortens the illness. Unfortunately, some Shigella bacteria have become resistant to antibiotics and using antibiotics to treat shigellosis can actually make the germs more resistant in the future. Persons with mild infections will usually recover quickly without antibiotic treatment. Therefore, when many persons in a community are affected by shigellosis, antibiotics are sometimes used selectively to treat only the more severe cases. Antidiarrheal agents such as loperamide (Imodium*) or diphenoxylate with atropine (Lomotil*) are likely to make the illness worse and should be avoided. 

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There is no vaccine to prevent shigellosis.
Basic food safety precautions and regular drinking water treatment prevents shigellosis. Avoid water or food that may be contaminated.
When traveling in countries where the water supply may be unsafe, avoid drinking unsafe water and avoid uncooked foods washed with unsafe tap water 
Wash your hands with soap and safe water after using the toilet, changing diapers, and before eating or preparing food. 

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Yes. Shigella are present in the diarrheal stools of infected persons while they are sick and for a week or two afterwards However, the risk of spreading infection is low if the infected person practices good personal hygiene. This includes thorough hand washing with soap and water after using the toilet and before handling food.
It is particularly likely to occur infection among toddlers who are not fully toilet-trained. Family members and playmates of such children are at high risk of becoming infected. 
People who have shigellosis should not prepare food or pour water or swim in pools until they have been shown to no longer be carrying the Shigella bacterium. 

This fact sheet is for information only and is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the disease described above or think that you may have another one, consult a health care provider.

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