Typhoid is an infection caused by the bacterium Salmonella typhimurium (S. typhi). The bacterium lives in the intestines and bloodstream of humans. It spreads between individuals by direct contact with the feces of an infected person.
No animals carry this disease, so transmission is always human to human. If untreated, around 1 in 5 cases of typhoid can be fatal. With treatment, fewer than 4 in 100 cases are fatal.
S. typhi enters through the mouth and spends 1 to 3 weeks in the intestine. After this, it makes its way through the intestinal wall and into the bloodstream.
From the bloodstream, it spreads into other tissues and organs. The immune system of the host can do little to fight back because S. typhi can live within the host’s cells, safe from the immune system. Typhoid is diagnosed by detecting the presence of S. typhi via blood, stool, urine, or bone marrow sample.
Causative agent
The typhoid bacillus Salmonella typhi, which infects humans only. Paratyphoid and enteric fevers are caused by other species of Salmonella, which infect domestic animals as well as humans.
Symptoms
In early stages of the disease, symptoms include: abdominal pain, fever, and a general feeling of being unwell. These initial symptoms are similar to other illnesses.
As typhoid fever gets worse, symptoms often include:
• High fever of up to 104 degrees Fahrenheit
• Headaches
• Abdominal pain, constipation then perhaps diarrhea later
• Small, red spots on your abdomen or chest (rose-colored spots)
• Loss of appetite and weakness.
• Body aches
• Bloody stools
• Chills
• Severe fatigue
• Difficulty paying attention
• Agitation, confusion, and hallucinations (seeing or hearing things that are not real)
Diagnosis
• Assessment to check for typhoid fever symptoms. Any history of similar infection within the patient's social circle or family is obtained as are the details of any recent travel to countries where typhoid is prevalent. Endemic areas include countries in Africa, the Indian subcontinent, South East Asia, and South America.
• Blood, stool and urine samples are collected so they can be checked under the microscope for the presence of Salmonella typhi. However, the bacteria may not always be detected in the early stages of disease and a series of tests may be needed to confirm the diagnosis.
• Testing the bone marrow is a more reliable method for diagnosing typhoid. However, obtaining a bone marrow sample is painful and is therefore avoided if possible.
• Blood culture is another common method of diagnosis. Blood drawn from the patient is placed on a culture media, which allows any bacteria present to grow and be detected under a microscope. For this test, around 10 to 15 ml of blood is drawn from adults and around 2 to 4 ml is drawn from toddlers and children, as children have a higher concentration of bacteria in their blood.
• A stool culture may also provide results by allowing the bacteria to grow in a culture media.
• Serum samples can be tested for antibodies against typhoid. For this test, 1 to 3 ml of blood is collected in a tube that does not contain an anticoagulant so that the clear serum portion of the blood can be separated off and tested for antibody titre.
• The Widal test involves testing for agglutinating antibody levels against O antigens which usually appear 6 to 8 days after disease onset and H antigens which appear on days 10 to 12. However, the use of more recent tests such as the IDL Tubex test and the Typhidot test allow for a more rapid detection of the antibodies, leading to a faster diagnosis.
Treatment
• The only effective treatment for typhoid is antibiotics. The most commonly used are ciprofloxacin (for non-pregnant adults) and ceftriaxone.
• Other than antibiotics, it is important to rehydrate by drinking adequate water.
• In more severe cases, where the bowel has become perforated, surgery may be required.
• Typhoid antibiotic resistance. As with a number of other bacterial diseases, there is currently concern about the growing resistance of antibiotics to S.typhi.
• This is impacting the choice of drugs available to treat typhoid. In recent years, for example, typhoid has become resistant to trimethoprim-sulfamethoxazole and ampicillin.
• Ciprofloxacin, one of the key medications for typhoid, is also experiencing similar difficulties. Some studies have found Salmonella typhimurium resistance rates to be Other treatments
Other treatments include:
• Drinking fluids. This helps prevent the dehydration that results from a prolonged fever and diarrhea. If you're severely dehydrated, you may need to receive fluids through a vein (intravenously).
• Surgery. If your intestines become perforated, you'll need surgery to repair the hole.
Prevention
• In many developing nations, the public health goals that can help prevent and control typhoid fever — safe drinking water, improved sanitation and adequate medical care — may be difficult to achieve. For that reason, some experts believe that vaccinating high-risk populations is the best way to control typhoid fever.
• A vaccine is recommended if you live in or you're traveling to areas where the risk of getting typhoid fever is high.
There are two vaccines available to prevent typhoid fever:
• Vivotif (Typhoid Vaccine Live Oral Ty21a) – Also known as ‘typhoid pills’, Vivotif is made from attenuated live bacteria. The vaccine provides up to five years’ protection and is approved for use in individuals over six-years-old. Vivotif is taken orally over the course of four doses.
• Typhoid Vaccine (Injectable) – Made from inactive bacteria, the injectable typhoid vaccine provides protection for up to two years. This vaccine is approved for use in individuals over two-years-old.
The risk of either typhoid vaccination causing serious harm is rare and reactions to either vaccine are generally mild.
Neither vaccine is 100 percent effective, and both require repeat immunizations, as vaccine effectiveness diminishes over time.
Because the vaccine won't provide complete protection, follow these guidelines when traveling to high-risk areas:
• Wash your hands. Frequent hand-washing in hot, soapy water is the best way to control infection. Wash before eating or preparing food and after using the toilet. Carry an alcohol-based hand sanitizer for times when water isn't available.
• Avoiding food that is raw or undercooked
• Drinking only bottled water or water that has been boiled
• Avoiding raw fruits and vegetables that cannot be peeled.
• Avoiding eating foods and beverages purchased from street vendors.