Tropical sprue is a digestive problem that occurs in the tropics and subtropics. People with tropical sprue do not absorb nutrients properly, especially vitamin B12 and folic acid.
Normal small intestines have fingerlike projections called villi that provide more surface area for nutrients to be absorbed. In people with tropical sprue, these villi are flattened, making absorption difficult.
Tropical sprue is rare except in a specific geographical zone. It occurs from about 30 degrees north of the equator to 30 degrees south of it. It is more common in certain countries within this tropical area, including India, Southeast Asian countries, Haiti, Cuba, Puerto Rico and the Dominican Republic. The condition afflicts residents of the affected countries as well as travelers, though usually it affects only travelers who stay for a month or longer.
The cause of tropical sprue has not been identified, but many experts suspect that an intestinal infection is to blame. When tropical sprue occurs, the lining of the small intestine is damaged so that it is unable to absorb nutrients efficiently.
Diarrhea is the main symptom of tropical sprue. Meals with fatty foods can cause oily, foul-smelling stools. Other symptoms include cramps, nausea, weight loss, gas and indigestion.
Diagnosis of tropical sprue can require a series of tests, because many conditions have similar symptoms. Your physician will order stool and blood tests to check for other causes of diarrhea. If these are negative and you have lived in the tropics for a long period, then tropical sprue is a potential cause for your illness. The most common way to confirm the diagnosis of tropical sprue is to do a biopsy, in which small piece of tissue is removed from your small bowel to be examined under a microscope. To do this procedure, your doctor will need to examine your stomach and small intestines through a small camera on a flexible cord (an endoscope) that is gently passed into your mouth and down your esophagus.
Certain blood tests also can give an indication that you might have tropical sprue. Because the disease blocks certain vitamins and minerals from being absorbed, you may have low levels of albumin, calcium or vitamins D, A, K and E. You also may have anemia (a low count of red blood cells) due to vitamin B12 and folate deficiencies. In addition, stool specimens may demonstrate an excess amount of fat.
Once treatment has started, most people are relieved of symptoms within weeks.
Other than avoiding tropical climates, there are no known ways to prevent tropical sprue.
Treatment is usually 3 to 6 months of an antibiotic named tetracycline and folic acid (also called folate) supplements. People with vitamin B12 deficiency will receive vitamin supplements as well.
Contact your doctor if you have diarrhea that does not respond to over-the-counter treatments. If you have lived in a tropical country and you have persisting diarrhea, you should be tested for parasitic infections and your doctor should consider whether you may have developed tropical sprue. Once you are undergoing treatment for tropical sprue, contact your doctor's office if the condition does not respond after several weeks.
The outlook for tropical sprue in travelers is usually excellent. In about 20% of tropical residents who have tropical sprue, the disease comes back after treatment.
Centers for Disease Control and Prevention (CDC)
National Center for Infectious Diseases
Division of Bacterial and Mycotic Diseases
1600 Clifton Road
Atlanta, Georgia 30333