Introduction – Typhoid Fever (Enteric Fever) 

Typhoid fever, also known as enteric fever, Typhoid is an infection caused by Salmonella typhi bacteria. This infection leads to fever and spreads through ingesting contaminated food and water.

The causative agent of Typhoid fever is Salmonella typhi, which cause rise to inflammatory destruction of the mucosa of the G.I. tract.

The bacterium responsible for typhoid is called Salmonella typhi and Salmonella Paratyphi bacteria (Paratyphi A, Paratyphi B, or Paratyphi C) cause paratyphoid fever.

Typhoid fever is a bacterial infection that can cause high fever, diarrhea, and vomiting. Without treatment, It can be fatal.

The exposure of infection is often passed on through contaminated food and drinking water, and it is more prevalent in places where handwashing is less frequent.

Epidemiological Triad of Typhoid Fever

Agent- The causative agent of typhoid fever is bacteria Salmonella typhi, gram negative bacillus. 

Agent is being present in case and carriers in their stool (poop) or urine (pee).

Host factor- Humans are the only reservoir for Salmonella typhi. Typhoid fever can occur in any age but the highest incidence in 5-19 years of age group.

Environment- Peak incidence during the rainy season, Contaminated food and water, Open defaecation and urination, Poor personal and environmental hygiene.

Source of Infection

Typhoid fever have two sources of infection – primary and secondary source.

Primary sources of infection –  Urine and faeces of case and carriers

Secondary sources of infection –  Contaminated water, food, fingers, flies etc.

Incubation Period

The incubation period for typhoid fever is typically 6 to 30 days  it can range from 3 days to 3 weeks.

Pathophysiology of Typhoid Fever

1. Ingested contaminated food and water (salmonella bacteria)

2. Ingested bacilli invade small intestinal mucosa and enter into blood stream

3. Taken up by macrophage and transport to regional lymph node

4. Salmonella typhi multiply in the intestinal lymphoid tissue and carried to liver, spleen and bone marrow.

During 1-3 week of incubation period (Diarrhoea occur)

4. Bacilli re- enter bloodstream (bacteraemia phase)

5. Onset of typhoid fever

6. Bacteria invade the biliary system, gall bladder, and lymphoid tissue of the intestine and multiply in high number

7. Then pass into intestinal tract (stool)

8. Identified by stool tested in laboratory

Mode of Transmission

Portal of entry-fecal-oral route

Direct – By soiled hands contaminated with faeces or urine of a case or carrier.

Indirect – By contaminated food, water, milk etc.

Clinical Manifestation of Typhoid Fever

1. High Fever

2. Sore throat/ Cough

3. Headache

4. Malaise/ Lethargy/ Nausea

5. Abdominal pain

6. Abdomen ache

7. Constipation or diarrhea

8. Abdominal distention

9. Abdominal tenderness

10. Vomiting

11.  Rash on the trunk appear during 2^nd week of disease

What is the Starting stage of Typhoid?

In early stages of the disease, initial symptoms of typhoid include – abdominal pain, fever that are similar to other illnesses. Typhoid fever gets worse, symptoms often include – High fever;104 degrees Fahrenheit.

Typhoid Symptoms in Adult

1. Fever that starts low and increases daily, possibly reaching as high as 104.9 F (40.5 C)

2. Headache

3. Weakness and fatigue

4. Muscle aches

5. Sweating

6. Dry cough

7. Loss of appetite and weight loss

8. Stomach pain

Typhoid Symptoms in Child

1. Fever that can reach as high as 104°F (40°C)

2. Diarrhea 

3. Coated tongue

4. Muscle aches

5. Rashes appear small pink spots on child’s chest and tummy

6. Headache

7. Abdominal pain

8. Feeling sick /tiredness / weakness

9. Loss of appetite

Lab Investigation

1. Blood for Widal test

2. Stool for culture

3. Urine for culture

Complication of Typhoid

1. Intestinal haemorrhage (Intestinal bleeding or holes)

2. Severe stomach pain

3. Shock

4. Pneumonia

5. Thrombophlebitis (inflammatory condition of the veins due to a blood clot)

6. Nephritis

7. Spleenomegaly

8. Bloodstream infection (sepsis)

Treatment of Typhoid Fever

Antibiotic treatment

1. For case- Chloramphenicol

2. For carrier- Ampicillin

Prevention of Typhoid Fever

Immunization

Typhoid fever vaccination– Three typhoid fever vaccines are available

1. Live Oral vaccine – Live attenuated (weakened) vaccine, Ty21a, administered orally (by mouth)

Live attenuated (weakened) vaccine, Ty21a, administered orally (by mouth) – Given to people at least 6 years old and recommended should be given at least 1 week before travel.  Oral typhoid vaccine requires a booster every 5 years.

2. Whole-cell inactivated vaccine, injectable (shot) vaccine

3. Vi capsular polysaccharide vaccine (ViCPS), (parenteral)

Type of Vaccine which are Available are –

 Monovalent typhoid vaccines, bivalent anti-typhoid vaccine and TAB Vaccines.

Age                           Dose     1^st dose    2^nd dose                   Route

1-10 years                0.25ml                    0.25ml                      S/C

Above 10 years       0.5ml                       0.5ml                        S/C

Note – One dose of typhoid vaccine shot is recommended at least 2 weeks before travel. Repeated doses are recommended every 2 years for individuals who remain at risk of infection.

 Control of Typhoid Fever

1. Early detection of cases and identification of carrier

2. Always practice safe eating food and drinking water habits

3. Isolation

4. Surveillance

5. Disinfection

6. Supply of safe water

7. Improvement of sanitation

8. Food Hygiene

To know other infection that cause diarrheal disease, such as  Cholera, Bacillarydysentery, Amoebic dysentery Checkout here.