Typhoid (Enteric Fever)

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  • Typhoid is a bacterial infection that can lead to a high fever, diarrhea, and vomiting. If typhoid is diagnosed early, it can be successfully treated with antibiotics; if it is not treated, typhoid can be fatal. The name typhoid is given to the disease by Louis in 1829, as a derivative from typhus.
  • Typhoid fever has received many names such as gastric fever, abdominal typhus, infantile intermittent fever, slow fever, nervous fever, pathogenic fever, etc.
  • Worldwide, typhoid fever affects roughly 17 million people annually, causing nearly 600,000 deaths. The disease is common in children of the age group 1-15 years.
  • Approximately 3%-5% of patients become carriers of the bacteria after the acute illness.
  • It is thought to have caused the deaths of many famous figures such as British author and poet Rudyard Kipling(the writer of The Jungle Book), the inventor of the airplane, Wilbur Wright, and the Greek Empire’s Alexander the Great.

Typhoid Mary:

  • It is a classic case in medicine.  Mary Mallon was born in 1869 in Ireland and emigrated to the US in 1884. She had worked in a variety of domestic positions for wealthy families prior to settling into her career as a cook. She was a healthy carrier of Salmonella typhi and spread typhoid for several years through the food she used to serve. Hence she was nicknamed “Typhoid Mary”.

Pathogen:

  • Typhoid is caused by acute infection of the intestine by rod-shaped bacteria Salmonella typhi. Originally it was isolated by Karl J. Erberth in 1880. It inhabits the lymphatic tissues of the small intestine, liver, spleen, and bloodstream of infected humans. It is most common in developing countries with poor sanitary systems and lack of antibiotics.

Typhoid

  • This gram-negative enteric bacillus belongs to the family Enterobacteriaceae. It is a motile, facultative anaerobe that is susceptible to various antibiotics. Its pathogenicity is due to an outer membrane consisting largely of lipopolysaccharides (LPS). LPS protect the bacteria from the environment. The LPS is made up of an O-antigen, a polysaccharide core, and lipid A. The lipid A is made up of two phosphorylated glucosamines which are attached to fatty acids. These phosphate groups determine the toxicity of bacteria. Animals carry an enzyme that specifically removes these phosphate groups in an attempt to protect themselves from these pathogens. The O -antigen is on the outermost part of the LPS complex. This arrangement is responsible for the host immune response and makes it difficult for antibodies to recognize.
  • Up till now, 107 strains of this organism have been isolated.

Modes of Transmission:

  • Transmission takes place through faecal-oral route.
  • People with acute illness can contaminate the surrounding water supply through stool, which contains a high concentration of the bacteria. Contamination of the water supply can, in turn, taint the food supply. The bacteria can survive for weeks in water or dried sewage. Houseflies are main vectors.
  • The infection is often passed on through contaminated food and drinking water, and it is more prevalent in places where handwashing is less frequent. It can also be passed on by carriers who do not know they carry the bacteria.

Incubation Period:

  • It is 1-3 weeks.
  • After the ingestion of contaminated food or water, the Salmonella bacteria invade the small intestine and enter the bloodstream temporarily. The bacteria are carried by white blood cells in the liver, spleen, and bone marrow, where they multiply and reenter the bloodstream. People develop symptoms, including fever, at this point.
  • Bacteria invade the gallbladder, biliary system, and the lymphatic tissue of the bowel. Here, they multiply in high numbers. The bacteria pass into the intestinal tract and can be identified in stool samples.

The Course of Disease:

  • The course of untreated typhoid fever is divided into four individual stages, each lasting approximately for one week.

Symptoms:

  • The two major symptoms of typhoid are fever and rash.
  • Typhoid fever is particularly high, gradually increasing over several days up to 104 degrees Fahrenheit. Pulse rate is low. The rash consists of rose-colored spots, particularly on the neck and abdomen.
  • Other symptoms can include Poor appetite, weakness, abdominal pain, constipation, headaches
  • In some cases, the symptoms might include confusion, diarrhoea, and vomiting, but this is not normally severe.

Confirmation of Infection:

  • Presence of Salmonella typhi is confirmed by Widal Test.

Treatment:

  • The only effective treatment for typhoid is antibiotics. The patient is treated with antibiotics such as Terramycin and Chloromycetin. The most commonly used are ciprofloxacin (for non-pregnant adults) and ceftriaxone. Continuous rehydration is required by drinking adequate water.
  • Chloramphenicol was the original drug of choice for many years. Because of rare serious side effects, chloramphenicol has been replaced by other effective antibiotics. The choice of antibiotics is guided by identifying the geographic region where the infection was contracted.
  • Those who become chronically ill (about 3%-5% of those infected), can be treated with prolonged antibiotics. Often, removal of the gallbladder, the site of chronic infection, will provide a cure.
  • People who test positive as carriers may not be allowed to work with children or older people until medical tests show that they are clear.

Typhoid Antibiotic Resistance:

  • There is concern about the growing resistance of antibiotics to S. typhi. Typhoid has become resistant to trimethoprim-sulfamethoxazole and ampicillin. Ciprofloxacin is also experiencing similar difficulties.

Prevention:

  • Countries with less access to clean water and washing facilities typically have a higher number of typhoid cases.

Preventing Infecting Yourself (For Healthy Person):

  • Wash hands frequently in hot, soapy water before eating or preparing food, as well as after using the toilet.
  • Use alcohol-based sanitizer in the absence of hot water.
  • Use boiled or bottled water for drinking.
  • Eat foods that have been thoroughly cooked and served hot and avoid foods that have been stored or served at room temperature.
  • Eat raw vegetables after peeling them.
  • Avoid food and drink being sold by street vendors.

Preventing Infecting Others (For Recovering Patient):

  • follow the doctor’s instructions for taking antibiotics and be sure to complete the whole course.
  • Avoid preparing food for others until it is confirmed that you are no longer contagious.
  • Wash hands frequently using hot, soapy water before preparing or eating food, as well as after using the toilet.

Vaccination:

  • Vaccines are not 100 percent effective and caution should still be exercised when eating and drinking.
  • Before traveling to a high-risk area, getting vaccinated against typhoid fever is recommended. This can be achieved by oral medication or a one-off injection (shot).

Live Typhoid Vaccine (Oral):

  • It is a live, attenuated vaccine.
  • Four doses: one capsule every other day for a week (day 1, day 3, day 5, and day 7). The last dose should be given at least 1 week before travel to allow the vaccine time to work.
  • Swallow each dose about an hour before a meal with a cold or lukewarm drink. Do not chew the capsule.
  • A booster dose is needed every 5 years for people who remain at risk.
  • Side Effects (Reaction):

  • Fever or a headache (up to about 1 person in 20)
  • Stomach pain, nausea, vomiting, rash (rare)
  • Who Should Not Take Vaccination?

  • Children younger than 6 years of age, anyone who has had a severe reaction to a previous dose of this vaccine, anyone who has a severe allergy to any component of this vaccine, anyone who is moderately or severely ill at the time the vaccine should not be administered with the vaccine.
  • Anyone whose immune system is weakened which includes anyone who has HIV/AIDS or another disease that affects the immune system has any kind of cancer and taking cancer treatment with radiation or drugs. should not be administered with vaccine directly. Oral typhoid vaccine should not be given until at least 3 days after taking antibiotics.

Inactivated Typhoid Vaccine (Shot)

  • One dose provides protection. It should be given at least 2 weeks before travel to allow the vaccine time to work.
  • A booster dose is needed every 2 years for people who remain at risk.
  • Side Effects (reaction):

  • Fever (up to about 1 person in 100)
  • A headache (up to about 1 person in 30)
  • Redness or swelling at the site of the injection (up to about 1 person in 15)
  • Who Should Not Take Vaccination?

  • Should not be given to children younger than 2 years of age, anyone who has had a severe reaction to a previous dose of this vaccine, anyone who has a severe allergy to any component of this vaccine and anyone who is moderately or severely ill at the time the shot.

Eliminating Typhoid:

  • Even when the symptoms of typhoid have passed, it is still possible to be carrying the bacteria. This makes it hard to eliminate the disease, because carriers whose symptoms have finished may be less careful when washing food or interacting with others.
Science > Biology > Health and DiseasesYou are Here
Physics Chemistry  Biology  Mathematics

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