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What is Amoebic Dysentery?
Amoebic Dysentery is an infection of the bowels caused by a parasite. This parasite can actually stay in the intestines for long periods of time and not cause any illness. It is only when the infection breaks through the lining and into the colon that it causes very severe diarrhea. This form of diarrhea is very painful and can be accompanied by bleeding, pus in the stool and dehydration.
This form of diarrhea is most common in tropical areas and comes from contaminated water and food. It is actually very rare, with only 10% of exposed individuals becoming ill from the parasite. Factors that increase the risk are poor hygiene and sanitation. Person to person contact can also spread the infection due to poor hand washing practices. It lives in human feces, so not washing your hands after using the restroom can spread the infection to others.
What causes Amoebic Dysentery?
Figure 1: Entamoeba histolytica
Courtesy of news-medical.net
Amoebic Dysentery is caused by the parasite Entamoeba histolytica (See Figure 1). This parasite invades the large intestine and lives there. The infection becomes severe and has symptoms only after the parasite has burrowed through the wall of the colon. The parasite can also spread into the bloodstream and to other parts of the body including; the liver, the heart and the lungs. In very severe cases, it can invade the brain.
People come into contact with this parasite by drinking contaminated water, eating contaminated food or touching others that have the infection and are unclean. It is most common for travelers to experience “travelers diarrhea” when they travel to tropical regions. (See Figure 2) Forms of this infection have also been found on cruise ships that travel to tropical locations. Some countries practice using human feces to fertilize their crops. When the food supply is contaminated with human feces, there is a chance of spreading the infection. Dysentery can also be spread by sexual contact.
Figure 2: High Risk Locations for Amoebic Dysentery
Courtesy of parasiticdiseases.blogspot.com
There are also certain risk factors that increase the chances of getting sick from dysentery. These factors lower the body’s immune response to the parasite. These factors include; young age, elderly, pregnancy, alcoholism, recent travel out of the country and cancer. Most people who come into contact with the parasite do not experience illness, but a lower immune system will not be able to fight off the infection.
What are the symptoms of Amoebic Dysentery?
The symptoms of dysentery may come and go and last for up to 2 weeks. They start about 7 to 10 days after the exposure to the parasite with a severe diarrhea that contains blood and pus. People with this infection can pass either 10 to 20 liquid stools daily or in milder cases up to 8 soft stools daily. The other symptoms vary from person to person and can range from:
- Severe abdominal pain
- Belching and flatulence
- Weight Loss
- Blood and Pus in the stools
- Mild to moderate fever
- Rectal Pain
There are severe complications associated with this infection and fluid replacement needs to be given to prevent dehydration. If severe dehydration occurs, it may result in seizures, mental status changes and coma. The infection can cause death as quickly as 24 hours if left untreated. The milder complication of this infection is perforation of the bowels, although this complication is still very serious and needs emergency care.
Amoebic dysentery is diagnosed by a history of recent travel, symptoms, visualization of the bowel with a scope, blood testing and stool cultures. After diagnosis, the doctor will be able to determine appropriate treatment.
How is Amoebic Dysentery treated?
The treatment for dysentery is an antibiotic that kills the parasite called, metronidazole. This antibiotic is usually started along with intravenous fluids and medication to control diarrhea, nausea and vomiting. Oral food and fluids are usually withheld until the diarrhea and/or vomiting subsides. This allows the bowel to rest and recover from the infection. When oral intake is finally allowed, the patient is usually started on clear liquids and then advanced to a soft, bland diet and so forth.
If patients receive quick treatment, the infection usually clears up without complications. Once antibiotics are finished, the stool is usually rechecked for any lingering presence of the parasite. If the full course of antibiotics is not finished, the infection can come back. This is why it is important to take all antibiotics for this condition even if you are feeling better.
The outcome of amoebic dysentery is usually very good and most patients recover without having any lasting problems. It is the patient’s that defer treatment that experience severe complications or re-occurrences of the infection.
If traveling out of the country, take measures to protect drinking water and food. Wash all fruits and vegetable thoroughly with purified, bottled water. Do not drink tap water or fresh water from streams. Wash hands thoroughly after using the restroom or coming into contact with surfaces that may be contaminated i.e. bathroom counters, cooking surfaces, etc.
With these tips, next time you are in the tropics you can enjoy the sunshine!