Typhoid Fever Information
Typhoid Fever is a serious bacterial infection of the intestinal tract and sometimes the bloodstream caused by eating food or drinking water contaminated with Salmonella typhi. An almost identical disease called PARATYPHOID FEVER is caused by a related bacterium. Typhoid fever today is an uncommon disease in the United States, but it is still common in Latin America, Africa, and Asia. In 1942 there were 4,000 reported U.S. cases, but since 1964 only about 400 cases have occurred each year, mostly imported from Mexico or India.
An estimated 16 million cases of typhoid fever and 600,000 related deaths occur worldwide, and 2.6 cases of typhoid fever were reported to the U.S. Centers for Disease Control and Prevention (CDC) per 1 million U.S. citizens and residents traveling abroad between 1992 through 1994. Before the advent of antibiotics, 12 percent of victims died. Today fewer than 10 percent of cases are fatal; these occur in malnourished infants and children.
About 3 percent of those who recover from a mild illness become chronic carriers. Carriers are infectious for years unless they are treated with antibiotics. Thomas Willis first described typhoid fever in 1643; typhoid fever was often confused with “typhus” fever until the two were distinguished in 1837, and the name “typhoid” fever—meaning typhoid-like—was coined.
Causes
Typhoid fever is caused by the bacterium Salmonella typhi, a species of salmonella. While the common salmonella species in the United States live in animals and infect humans via contaminated food (chicken, eggs, etc.), S. typhi lives in the intestinal tract of humans. Once ingested, the bacteria lodge in the lower small intestine, where it multiplies and invades the bloodstream.
The disease is contracted from food or water that has been contaminated by the feces of patients or carriers, or from intimate contact with an infected person. It occurs in developing countries from eating shellfish taken from contaminated beds, eating raw fruits, or drinking tainted water supplies. It can also be contracted from food left outdoors accessible to flies. Anyone can get typhoid fever, but today the greatest risk is to children visiting countries where the disease is common.
Children are infectious as long as the bacteria are being shed in feces (usually three to four weeks), but some may remain infectious up to three months. To be considered uninfectious, a child must have stool cultures every week until there are three negative cultures in a row. The most important modern source of the typhoid bacillus (found throughout the world) is the typhoid carrier; these carriers at times contaminate water, milk, or food and set off typhoid epidemics.
Symptoms
Between eight and 14 days after ingesting bacteria, symptoms of fever, headache, joint pains, sore throat, and constipation begin. There may be appetite loss and abdominal pain. Most children have a mild illness and recover without antibiotics. Untreated, the fever will continue to rise for two or three days, remain high for up to two weeks (103° to 104°F) and then fall. Nosebleed and bronchitis are often present. At the height of the fever, the child appears extremely ill and can be delirious.
Even when symptoms pass, the child may still carry S. typhi. Relapses occur in 10 percent of untreated patients and 20 percent of treated patients about two weeks after the fever abates. If the fever returns, antibiotics must be restarted. Some patients notice rose spots on chests and abdomens during the second week. Infection confers some immunity, but not enough to protect a patient if there are large numbers of bacteria ingested a second time.
Diagnosis
The diagnosis is confirmed by obtaining a culture of typhoid bacteria from a sample of blood during the first week; feces and urine tests reveal the bacillus during the second. A blood test reveals the presence of antibodies against typhoid bacteria.
Complications
Children with serious cases can go on to experience frothy, bloody diarrhea in later stages and become apathetic. Typhoid fever can inflame the intestines, and in severe cases intestinal ulcers can perforate, causing severe infections. This can also lead to severe intestinal bleeding, which kills 25 percent of untreated patients.
Treatment
Antibiotics can shorten the disease and reduce chances of complications and death. Otherwise, it can take months to recover. Doctors may prescribe chloramphenicol, ciprofloxacin, ceftriaxone, or cefoperazone. In addition, patients need bed rest and good nutrition. Aspirin, enemas, or laxatives should not be given.
Gloves should be worn when nursing a typhoid patient, and rigorous hand washing is critical. Because the germ is passed in the feces of infected patients, only those with active diarrhea who cannot toilet themselves (infants and some handicapped people) should be isolated.
With early diagnosis and proper treatment, the outlook is usually excellent. Permanent immunity usually follows an attack of typhoid, although relapses are common if the disease is not fully eradicated by thorough antibiotic treatment. Most infected children may return to school when they have recovered, as long as they wash hands after toilet visits. Children in day care must obtain the approval of the local or state health department before returning to school.
Prevention
Typhoid fever is a reportable disease. Typhoid vaccination is not required for international travel, but it is recommended for travel to high-risk areas, including the Indian subcontinent and other developing countries in Asia, Africa, and Central and South America. Vaccination is particularly recommended for those who will be traveling in smaller cities, villages, and rural areas. However, typhoid vaccination is not completely effective and is not a substitute for careful selection of food and drink.
An oral vaccine (Ty21a) was licensed in 1990 that provides fewer side effects than the older vaccine. This new version provides between 70 and 90 percent protection and is recommended for any child over age six who is traveling off tourist routes (or for a long time) in Latin America, Asia, or Africa. The oral vaccine includes four capsules taken every other day for seven days. All four must be taken to provide maximum protection. The capsules should be kept refrigerated until they are taken with a cool liquid a half hour before a meal.
Antibiotics or the antimalarial drug mefloquine should not be taken at the same time. The entire four-dose series should be repeated every five years for those who need protection. There are few side effects with this drug, although some people notice nausea, vomiting, cramps, and skin rash.
The older injected vaccine caused fever, headache, and local pain and swelling in about one-third of patients. This oral vaccine is approved for children over age 6. The alternative is an injected vaccine called Typhim Vi is available in Canada and the United States and is equally effective with few side effects. It is approved for children over age two and should be taken two weeks before travel to allow immunity to develop.
Further preventive measures for travelers include drinking only pasteurized milk products, boiled or bottled water, or carbonated beverages; eating only cooked food or fruit with that is peeled by the diner; eating shellfish boiled or steamed at least 10 minutes; and controlling flies with screens and sprays.
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