Frequently Asked Questions
Shigellosis is an infectious disease
caused by a group of bacteria called Shigella. 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.
sort of germ is Shigella?
The Shigella germ is actually
a family of bacteria that can cause diarrhea in humans. They are
microscopic living creatures that pass from person to person.
Shigella were discovered over 100 years ago by a Japanese
scientist named Shiga, for whom they are named. There are several
different kinds of Shigella bacteria: Shigella sonnei,
also known as "Group D" Shigella, accounts for
over two-thirds of the shigellosis in the United States. A second
type, Shigella flexneri, or "group B" Shigella,
accounts for almost all of the rest. Other types of Shigella
are rare in this country, though they continue to be important
causes of disease in the developing world. One type found in the
developing world, Shigella dysenteriae type 1, causes deadly
can Shigella infections be diagnosed?
Many different kinds of diseases
can cause diarrhea and bloody diarrhea, and the treatment depends
on which germ is causing the diarrhea. Determining that Shigella
is the cause of the illness depends on laboratory tests that identify
Shigella in the stools of an infected person. These tests
are sometimes not performed unless the laboratory is instructed
specifically to look for the organism. The laboratory can also
do special tests to tell which type of Shigella the person
has and which antibiotics, if any, would be best to treat it.
can Shigella infections be treated?
Shigellosis can usually be treated
with antibiotics. The antibiotics commonly used for treatment
are ampicillin, trimethoprim/sulfamethoxazole (also known as
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.
there long term consequences to a Shigella infection?
Persons with diarrhea usually recover
completely, although it may be several months before their bowel
habits are entirely normal. 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
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.
do people catch Shigella?
The Shigella bacteria pass
from one infected person to the next. Shigella are present
in the diarrheal stools of infected persons while they are sick
and for a week or two afterwards. Most Shigella infections
are the result of the bacterium passing from stools or soiled
fingers of one person to the mouth of another person. This happens
when basic hygiene and handwashing habits are inadequate. It is
particularly likely to occur among toddlers who are not fully
toilet-trained. Family members and playmates of such children
are at high risk of becoming infected.
Shigella infections may 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 drinking or swimming in contaminated water. Water
may become contaminated if sewage runs into it, or if someone
with shigellosis swims in it.
can a person do to prevent this illness?
There is no vaccine to prevent shigellosis.
However, the spread of Shigella from an infected person
to other persons can be stopped by frequent and careful handwashing
with soap. Frequent and careful handwashing is important among
all age groups. Frequent, supervised handwashing of all children
should be followed in day care centers and in homes with children
who are not completely toilet-trained (including children in diapers).
When possible, young children with a Shigella infection
who are still in diapers should not be in contact with uninfected
People who have shigellosis should
not prepare food or pour water for others until they have been
shown to no longer be carrying the Shigella bacterium.
If a child in diapers has shigellosis,
everyone who changes the child's diapers should be sure the diapers
are disposed of properly in a closed-lid garbage can, and should
wash his or her hands carefully with soap and warm water immediately
after changing the diapers. After use, the diaper changing area
should be wiped down with a disinfectant such as household bleach,
Lysol* or bactericidal wipes.
Basic food safety precautions and
regular drinking water treatment prevents shigellosis. At swimming
beaches, having enough bathrooms near the swimming area helps
keep the water from becoming contaminated.
Simple precautions taken while traveling
to the developing world can prevent getting shigellosis. Drink
only treated or boiled water, and eat only cooked hot foods or
fruits you peel yourself. The same precautions prevent traveler's
diarrhea in general.
common is shigellosis?
Every year, about 18,000 cases of
shigellosis are reported in the United States. Because many milder
cases are not diagnosed or reported, the actual number of infections
may be twenty times greater. Shigellosis is particularly common
and causes recurrent problems in settings where hygiene is poor
and can sometimes sweep through entire communities. Shigellosis
is more common in summer than winter. Children, especially toddlers
aged 2 to 4, are the most likely to get shigellosis. Many cases
are related to the spread of illness in child-care settings, and
many more are the result of the spread of the illness in families
with small children.
In the developing world, shigellosis
is far more common and is present in most communities most of
else can be done to prevent shigellosis?
It is important for the public health
department to know about cases of shigellosis. It is important
for clinical laboratories to send isolates of Shigella
to the City, County or State Public Health Laboratory so the specific
type can be determined and compared to other Shigella.
If many cases occur at the same time, it may mean that a restaurant,
food or water supply has a problem which needs correction by the
public health department. If a number of cases occur in a day-care
center, the public health department may need to coordinate efforts
to improve handwashing among the staff, children, and their families.
When a community-wide outbreak occurs, a community-wide approach
to promote handwashing and basic hygiene among children can stop
the outbreak. Improvements in hygiene for vegetables and fruit
picking and packing may prevent shigellosis caused by contaminated
Some prevention steps occur everyday,
without you thinking about it. Making municipal water supplies
safe and treating sewage are highly effective prevention measures
that have been in place for many years.
is the government doing about shigellosis?
The Centers for Disease Control
and Prevention (CDC) monitors the frequency of Shigella
infections in the country, and assists local and State health
departments to investigate outbreaks, determine means of transmission
and devise control measures. CDC also conducts research to better
understand how to identify and treat shigellosis. The Food and
Drug Administration inspects imported foods, and promotes better
food preparation techniques in restaurants and food processing
plants. The Environmental Protection Agency regulates and monitors
the safety of our drinking water supplies. The government has
also maintained active research into the development of a Shigella
can I learn more about this and other public health problems?
You can discuss any medical concerns
you may have with your doctor or other heath care provider. Your
local city or county health department can provide more information
about this and other public health problems that are occurring
in your area. General information about the public health of the
nation is published every week in the "Morbidity and Mortality
Weekly Report", by the CDC in Atlanta, GA. Epidemiologists
in your local and State Health Departments are tracking a number
of important public health problems, investigating special problems
that arise, and helping to prevent them form occurring in the
first place, or from spreading if they do occur.
tips for preventing the spread of shigellosis:
- wash hands with soap carefully
and frequently, especially after going to the bathroom, after
changing diapers, and before preparing foods or beverages
- dispose of soiled diapers properly
- disinfect diaper changing areas
after using them
- keep children with diarrhea out
of child care settings
- supervise handwashing of toddlers
and small children after they use the toilet
- persons with diarrheal illness
should not prepare food for others
- if you are traveling to the developing
world, "boil it, cook it, peel it, or forget it"
- avoid drinking pool water
more information about this.)