Typhoid fever is caused by the bacterium Salmonella enterica serotype Typhi and is transmitted through contaminated food or water. It has a variable incubation period of 1-2 weeks. Clinical presentation includes a stepwise fever pattern, gastrointestinal symptoms like abdominal pain, and occasionally a rose-colored rash. Without treatment, typhoid fever can last 3-4 weeks and be life threatening, but with antibiotics mortality is low. It remains common in areas with poor sanitation.

1. Typhoid Fever
Dr Simbarashe Takuva

2. Outline of presentation
1. Introduction
2. Pathophysiology
3. Epidemiology
4. Clinical Presentation
5. Laboratory Investigations
6. Treatment
7. Prevention

3. Introduction
Famous people who have had the disease include
• Hashimoto Hakaru, discoverer Of Autoimmune Thyroiditis
Hashimoto's thyroiditis. Died on January 9, 1934, of typhoid fever.
• Mary Mallon, more commonly known as Typhoid Mary, survived a
childhood episode in Ireland to become an asymptomatic carrier in
the United States.
• Edward VII survived.
• Louisa May Alcott, author of Little Women, records contracting it in
Hospital Sketches.
• Charles Darwin, naturalist, during his visit to Chile with HMS Beagle in
1835.
• Leland Stanford Jr. died of typhoid in 1884; his parents founded
Stanford University in his memory.

4. Introduction
• Typhoid (typhoid fever): common worldwide illness,
transmitted by the ingestion of food or water
contaminated with the feaces of an infected person,
which contain the bacterium Salmonella enterica,
serotype Typhi.
• The organism is a Gram-negative short bacillus that
is motile due to its peritrichous flagella. The bacterium
grows best at 37degrees – human body temperature.
• The name of "typhoid" comes from the
neuropsychiatric symptoms common to typhoid and
typhus (from Greek τῦϕος, "stupor")
• Humans are the only hosts for S. typhi.

5. Introduction
• Salmonella is a Gram-negative facultative rod-shaped
bacterium in the same proteobacterial family as
Escherichia coli, the family Enterobacteriaceae, trivially
known as "enteric" bacteria
• Salmonella is nearly as well-studied as E. coli from a
structural, biochemical and molecular point of view, and as
poorly understood as E. coli from an ecological point of
view
• Salmonellae live in the intestinal tracts of warm and cold
blooded animals. Somes pecies are specifically adapted
to a particular host
• In humans, Salmonella are the cause of two diseases
called salmonellosis: enteric fever (typhoid), resulting
from bacterial invasion of the bloodstream, and acute
gastroenteritis, resulting from a foodborne
infection/intoxication

6. Introduction
• A person may become an asymptomatic carrier of
typhoid fever
• c.a. 5% of people who contract typhoid continue to
carry the disease after they recover.
• Modes of transmission:
• Oral transmission via food or beverages handled
by an individual who chronically sheds the bacteria
through stool or, less commonly, urine
• Hand-to-mouth transmission after using a
contaminated toilet and neglecting hand hygiene
• Oral transmission via sewage-contaminated water
or shellfish (especially in the developing world)
• Sexual transmission

7. Pathophysiology
• Following ingestion of contaminated food or water (>104 bacteria),
Salmonella gain entry into the small intestine after a variable incubation
period of 1-2 weeks
• Bacteria attach themselves to epithelium and subsequently penetrate
lamina propria and submucosa where they are engulfed by monocytes
• Bacteria resist intracellular killing and multiply in the monocytes
• They reach mesenteric lymph nodes, multiply there and reach blood
stream via thoracic duct resulting in primary bacteremia
• During this transient bacteremia bacteria are seeded in the liver, gall
bladder, spleen, lymph node, bone marrow, where they continue to
multiply
• Following multiplication in large numbers, the bacteria spill in to
bloodstream again resulting in secondary bacteremia and marks the
onset of clinical disease
• When bacteria are shed from the gall bladder along with the bile juice,
they reach the small intestine again and infect the peyer's patches and
lymphoid follicles of ileum leading to inflammation and ultimately

9. Epidemiology
• More common in regions where sanitary conditions are
poor particularly in Southeast Asia, Africa and Latin
America.
• WHO estimates globally 16 million and 33 million cases
annually, with 500 000 to 700 000 deaths
• About 70% of all typhoid fever fatalities occur in Southeast
Asia
• In South Africa, an outbreak occurred in September 2005
in the town of Delmas leading to 3 346 cases of diarrhoea,
of which 596 were laboratory confirmed as being typhoid
cases
• The last major outbreak of typhoid in South Africa before
this one was in 1994 in the same town. There were 5
reported deaths

10. Epidemiology
Mortality and morbidity
• Without therapy, the illness may last for 3 to 4 weeks and
death rates range between 12% and 30%
• Untreated typhoid fever is a life-threatening illness of
several weeks' duration with long-term morbidity
• The case fatality rate in the United States in the pre-
antibiotic era was 9%-13%.
• With prompt and appropriate antibiotic therapy, typhoid
fever is typically a short-term febrile illness requiring a
median of 6 days of hospitalization
• Treated, it has few long-term sequelae and a 0.2% risk of
mortality

11. Epidemiology
Risk factors
• Anyone is at risk of typhoid fever infection, but there are
certain groups who due to circumstances are more at risk
than others and they include:
• Refugees
• Persons living in areas with poor water supply and
sanitation
• Travellers to typhoid endemic regions
• Health care workers

12. Epidemiology
Risk factors
• Anyone is at risk of typhoid fever infection, but there are
certain groups who due to circumstances are more at risk
than others and they include:
• Refugees
• Persons living in areas with poor water supply and
sanitation
• Travellers to typhoid endemic regions
• Health care workers

13. Clinical Presentation
7-14 days after ingestion of S. Typhi
• the fever pattern is stepwise, characterized by a rising
temperature over the course of each day that drops by
the subsequent morning
• GIT symptoms develop
• diffuse abdominal pain and tenderness and, in some
cases, fierce colicky right upper quadrant pain.
• onocytic infiltration inflames Peyer patches and
narrows the bowel lumen, causing constipation that
lasts the duration of the illness
• The individual then develops a dry cough, dull frontal
headache, delirium, and an increasingly stuporous
malaise.

14. Clinical Presentation
7-14 days after ingestion of S. Typhi
• At approximately the end of the first week of illness, the
fever plateaus at (39-40 C)
• The patient develops rose spots, which are salmon-
colored, blanching, truncal, maculopapules usually 1-4
cm wide and fewer than 5 in number; these generally
resolve within 2-5 days
• These are bacterial emboli to the dermis and
occasionally develop in persons with shigellosis or
nontyphoidal salmonellosis

15. Clinical Presentation
2nd week of illness
• These signs and symptoms listed above progress
• The abdomen becomes distended, and soft splenomegaly
is common
• Relative bradycardia and dicrotic pulse (double beat, the
second beat weaker than the first) may also develop

16. Clinical Presentation
3rd week of illness
• The still febrile individual grows more toxic and anorexic with
significant weight loss
• The conjunctivae are infected, and the patient is tachypneic
with a thready pulse and crackles over the lung bases
• Abdominal distension is severe
• Some patients experience foul, green-yellow, liquid diarrhea
(pea soup diarrhea)
• The individual may descend into the typhoid state, which is
characterized by apathy, confusion, and even psychosis
• Necrotic Peyer patches may cause bowel perforation and
peritonitis
• At this point, overwhelming toxemia, myocarditis, or intestinal
hemorrhage may cause death.

17. Clinical Presentation
4th week of illness
• If the individual survives to the fourth week, the fever,
mental state, and abdominal distension slowly improve
over a few days
• Intestinal and neurologic complications may still occur in
surviving untreated individuals
• Weight loss and debilitating weakness last months
• Some survivors become asymptomatic S typhi carriers and
have the potential to transmit the bacteria indefinitely

18. Clinical Presentation
Other presentations
• The timing of the symptoms and host response may vary based
on geographic region, race factors, and the infecting bacterial
strain
• The stepladder fever pattern that was once the hallmark of
typhoid fever now occurs in as few as 12% of cases. In most
contemporary presentations of typhoid fever, the fever has a
steady insidious onset.
• Young children, individuals with HIV/AIDS, and 1/3 of
immunocompetent adults who develop typhoid fever develop
diarrhea rather than constipation
• In addition, in some localities, typhoid fever is generally more
apt to cause diarrhea than constipation.

19. Clinical Presentation
Other presentations
• Atypical manifestations of typhoid fever include isolated severe
headaches that may mimic Meningitis, acute lobar pneumonia,
isolated arthralgias, urinary symptoms, severe jaundice, or fever
alone
• Some patients, especially in India and Africa, present primarily
with neurologic manifestations such as delirium or, in extremely
rare cases, parkinsonian symptoms or Guillain-Barré syndrome
• Other unusual complications include pancreatitis, meningitis,
orchitis, osteomyelitis, and abscesses anywhere on the body.