TYPHOID FEVER

Introduction

Typhoid fever is contracted when people eat food or drink water that has been infected with Salmonella typhi. It is recognized by the sudden onset of sustained fever, severe headache, nausea and severe loss of appetite. It is sometimes accompanied by hoarse cough and constipation or diarrhoea. Case-fatality rates of 10% can be reduced to less than 1% with appropriate antibiotic therapy. Paratyphoid fever shows similar symptoms, but tends to be milder and the case-fatality rate is much lower.

Identification

Typhoid fever is caused by Salmonella typhi, the typhoid bacillus. At present, there are 107 different strains of the bacteria. Typhoid fever is characterized by the sudden onset of sustained fever, severe headache, nausea, severe loss of appetite, constipation or sometimes diarrhoea. Severe forms have been described with mental dullness and meningitis. Case-fatality rates of 10% can be reduced to less than 1% with appropriate antibiotic therapy.

Paratyphoid fever can be caused by any of three variations or bioserotypes of S. enteritidis Paratyphi A, B and C. It is similar in its symptoms to typhoid fever, but tends to be milder, with a much lower case fatality rate.

Occurrence

Typhoid fever affects 17 million people worldwide every year, with approximately 600,000 deaths. The number of sporadic cases of typhoid fever has remained relatively constant in the industrialized world, and with the advent of proper sanitary facilities, has been virtually eliminated in many areas. Most cases in developed countries are imported from endemic countries. Strains resistant to chloramphenicol and other recommended antibiotics have become prevalent in several areas of the world. Multidrug resistant strains have been reported from Asia, the Middle East and Latin America.

Transmission

Typhoid fever is transmitted by food and water contaminated by the faeces and urine of patients and carriers. Polluted water is the most common source of typhoid. In addition, shellfish taken from sewage-contaminated beds, vegetables fertilized by nightsoil and eaten raw, contaminated milk and milk products have been shown as a source of infection.

Communicability

People can transmit the disease as long as the bacteria remain in their system; most people are infectious prior to and during the first week of convalescence. About 10% of untreated patients will discharge bacteria for up to three months; 2 to 5% of untreated patients will become permanent carriers.

Epidemic measures

An intensive search should be conducted for the case or carrier who is the source of the infection and for the means (water or food) by which the infection was transmitted. Routine use of vaccine is not recommended. Samples of blood can be taken immediately for confirmation, and testing for antibiotic sensitivity; samples of stool or urine may be taken after one week of onset for effective confirmation. Food and water samples should be taken from suspected sources of the outbreak for laboratory testing. It is also recommended to organize temporary water purification and sanitation facilities until longer term measures can be implemented.

Disaster implications

With disruption of the usual water supply and sewage disposal, and of the elimination or reduction of controls on food and water, transmission of typhoid fever may occur if there are active cases or carriers. Efforts to restore safe drinking water supplies and sanitary disposal facilities are essential. Selective immunization of groups such as schoolchildren, prisoners and utility, municipal or hospital personnel can be helpful.

Prevention

·        Protect and chlorinate public water supplies. Provide safe water supplies and avoid possible back flow connections between sewers and water supplies.

·        Dispose of human faeces in a sanitary manner and maintain fly-proof latrines.

·        Use scrupulous cleanliness in food preparation and handling.

·        Educate the public regarding the importance of hand washing: this is important for food handlers and attendants involved in the care of patients and/or children. Thorough and frequent hand washing is essential, especially after a bowel movement.

Vaccination/Travel advisory

Immunization for typhoid fever is recommended for international travelers to endemic areas, especially if travel will involve exposure to unsafe food and water or close contact in rural areas and with indigenous populations. Immunization is not a mandatory requirement for entry into any country and is not routinely recommended in industrialized countries.

 

SOME FACTS

How is typhoid fever spread?

Salmonella Typhi lives only in humans. Persons with typhoid fever carry the bacteria in their bloodstream and intestinal tract. In addition, a small number of persons, called carriers, recover from typhoid fever but continue to carry the bacteria. Both ill persons and carriers shed S. Typhi in their feces (stool).

You can get typhoid fever if you eat food or drink beverages that have been handled by a person who is shedding S. Typhi or if sewage contaminated with S. Typhi bacteria gets into the water you use for drinking or washing food. Therefore, typhoid fever is more common in areas of the world where hand washing is less frequent and water is likely to be contaminated with sewage.

Once S. Typhi bacteria are eaten or drunk, they multiply and spread into the bloodstream. The body reacts with fever and other signs and symptoms.

Where in the world do you get typhoid fever?

Typhoid fever is common in most parts of the world except in industrialized regions such as the United States, Canada, western Europe, Australia, and Japan. Therefore, if you are traveling to the developing world, you should consider taking precautions. Over the past 10 years, travelers from the United States to Asia, Africa, and Latin America have been especially at risk.

How can you avoid typhoid fever?

Two basic actions can protect you from typhoid fever:
1. Avoid risky foods and drinks.
2. Get vaccinated against typhoid fever.

It may surprise you, but watching what you eat and drink when you travel is as important as being vaccinated. This is because the vaccines are not completely effective. Avoiding risky foods will also help protect you from other illnesses, including travelers' diarrhea, cholera, dysentery, and hepatitis A.

"Boil it, cook it, peel it, or forget it"

• If you drink water, buy it bottled or bring it to a rolling boil for 1 minute before you drink it. Bottled carbonated water is safer than uncarbonated water.
• Ask for drinks without ice unless the ice is made from bottled or boiled water. Avoid popsicles and flavored ices that may have been made with contaminated water.
• Eat foods that have been thoroughly cooked and that are still hot and steaming.
• Avoid raw vegetables and fruits that cannot be peeled. Vegetables like lettuce are easily contaminated and are very hard to wash well.
• When you eat raw fruit or vegetables that can be peeled, peel them yourself. (Wash your hands with soap first.) Do not eat the peelings.
• Avoid foods and beverages from street vendors. It is difficult for food to be kept clean on the street, and many travelers get sick from food bought from street vendors.

What are the signs and symptoms of typhoid fever?

Persons with typhoid fever usually have a sustained fever as high as 103° to 104° F (39° to 40° C). They may also feel weak, or have stomach pains, headache, or loss of appetite. In some cases, patients have a rash of flat, rose-colored spots. The only way to know for sure if an illness is typhoid fever is to have samples of stool or blood tested for the presence of S. Typhi.

What do you do if you think you have typhoid fever?

If you suspect you have typhoid fever, see a doctor immediately. If you are traveling in a foreign country, you can usually call the U.S. consulate for a list of recommended doctors.

You will probably be given an antibiotic to treat the disease. Three commonly prescribed antibiotics are ampicillin, trimethoprim-sulfamethoxazole, and ciprofloxacin. Persons given antibiotics usually begin to feel better within 2 to 3 days, and deaths rarely occur. However, persons who do not get treatment may continue to have fever for weeks or months, and as many as 20% may die from complications of the infection.

Typhoid fever's danger doesn't end when symptoms disappear

Even if your symptoms seem to go away, you may still be carrying S. Typhi. If so, the illness could return, or you could pass the disease to other people. In fact, if you work at a job where you handle food or care for small children, you may be barred legally from going back to work until a doctor has determined that you no longer carry any typhoid bacteria.

If you are being treated for typhoid fever, it is important to do the following:

Keep taking the prescribed antibiotics for as long as the doctor has asked you to take them.

Wash your hands carefully with soap and water after using the bathroom, and do not prepare or serve food for other people. This will lower the chance that you will pass the infection on to someone else.
Have your doctor perform a series of stool cultures to ensure that no S. typhi bacteria remain in your body.