1. Enteric Fever
Dr. Priyamadhaba Behera
References
WHO Document, 5th edition OTPH, 18th edition Harrison
principle of medicine, Articles however applicable
1

2. Epidemiology
• Etiologic agents of enteric fever
– S. typhi and S. paratyphi serotypes A, B, and C
– No known hosts other than humans
• Estimated 22 million cases, with 200,000 deaths annually
• Incidence
Rate
Location
Cases per 1 Lakh opulation per Yr.
Highest
South central and Southeast Asia
>100
Medium
Rest of Asia, Africa, Latin America
and Oceania (excluding Australia
and New Zealand)
10–100
Low
Other parts of the world
<10

3. Epidemiology

4. Epidemiology
• Multidrug-resistant (MDR) strains of S. Typhi emerged
in 1989 in China and southeast Asia
• Resistance to chloramphenicol, ampicillin and
trimethoprim antibiotics long used to treat enteric
fever
• Increased use of fluoroquinolones to treat MDR
enteric fever in 1990s, reduced susceptibility to
ciprofloxacin [MIC, 0.125–1 g/ml] have emerged in
the Indian subcontinent, southern Asia
• Resistance - first-generation Quinolone nalidixic acid
detects most but not all strains with reduced
susceptibility to ciprofloxacin

5. Disease Outbreak Reported
• 17 June 2003 (Haiti)
– As of 30 May, 200 cases and 40 deaths, reported by WHO regional
office for the Americas (PAHO) and the MoH, Haiti
– Epidemic started in April in villages in the Grand Bois area, bordering
the Dominican Republic
• 15 December 2004 (Kinshasa)
– Total of 13400 cases were reported
– Between 1st October and 10th December 2004, 615 severe cases with
peritonitis, with or without perforation, including 134 deaths (case
fatality rate, 21.8%) have occurred
• 19 January 2005
– From 27 September 2004 - 11 January 2005, WHO reported total of
42564 cases and 214 deaths (case fatality ratio, 0.5%), and 696 severe
cases of intestinal perforation in Kinshasa
• Very poor sanitary conditions and a lack of drinking water
have been reported in all these areas

6. Mode of transmission
• Most commonly, food-borne or waterborne
• Faecal contamination by ill or asymptomatic chronic
carriers
• Health care workers -exposure to infected patients or
during
processing of clinical specimens and cultures
• Sexual transmission between male partners has been
described

7. Role of asymptomatic carrier in typhoid
George Soper
Dr. Sara Josephine Baker

8. Risk factors
•
•
•
•
Contaminated water or ice
Flooding
Contaminated food and drinks
Raw fruits and vegetables grown in fields fertilized
with sewage
• Lack of hand washing and toilet access
• Evidence of prior helicobacter pylori infection

9. Risk factors
Severe disease ( 10–15% of patients)
• Host factors (immunosuppression, antacid therapy,
previous exposure, and vaccination)
• Strain virulence and inoculums
• Choice of antibiotic therapy
Incubation period
• 3 - 21 days (average 10-14 days)

10. Symptoms
•Enteric fever is a misnomer
•Hallmark features of this
disease—fever and abdominal
pain—are variable
•Fever >75% of cases,
abdominal pain is reported in
only 30–40%

11. Symptoms
•
•
•
•
•
•
•
•
Sytemic symptoms
Headache (80%)
Chills (35–45%)
Cough (30%)
Sweating (20–25%)
Myalgias (20%)
Malaise (10%)
Arthralgia (2–4%)

12. Symptoms
Gastrointestinal symptoms
• Anorexia (55%)
• Abdominal pain (30–40%)
• Nausea (18–24%)
• Vomiting (18%)
• Diarrhea (22–28%)
• Constipation (13–16%)
2nd week

13. Signs
•Relative bradycardia
•Coated tongue (51–56%)
•Splenomegaly (5–6%)
•Abdominal tenderness (4–5%)
• Rose spots (30%)
End of the first week and resolves
without a trace after 2–5 days
Two or three crops of lesions
Salmonella can be cultured from punch
biopsies of these lesions
Faintness of rash makes difficult to
detect in highly pigmented patients

14. Investigations
• Definitive diagnosis of enteric fever by isolation of S.
Typhi or S. Paratyphi from blood, bone marrow,
other sterile sites, rose spots, stool, or intestinal
secretions
• Serologic tests- widal test
 ƒTiming of test is important
 ƒSingle test is usually of not much value
 ƒBaseline titre of the population must be known
before attaching significance to the titres (≥100 for O
and ≥200 for H)
 Treated with antibiotics may not show any rise
 False positive reactions
 Anamnestic response ƒƒ

15. Investigations
• None of these tests is sufficiently sensitive or specific
to replace culture-based methods for the diagnosis
• PCR and DNA probe assays to detect S. typhi in blood
have been identified but have not yet been
developed for clinical use

16. Treatment

17. Control
• Health education about personal hygiene, especially
regarding hand-washing after toilet use and before
food preparation
• Provision of a safe water supply
• Proper sanitation systems
• Excluding disease carriers from food handling

18. Control
• Possible to eliminate enteric fever since they
survive only in human hosts and spread by
contaminated food and water
• High prevalence of the disease in developing
countries that lack adequate sewage disposal and
water treatment, goal is currently unrealistic
• Travelers to developing countries should be
advised to monitor their food and water intake
carefully and to consider vaccination

19. Typhoid vaccines
Two typhoid vaccines are commercially available .
Currently, there is no licensed vaccine for paratyphoid
fever
Ty21a
– Oral live attenuated S. Typhi vaccine
– Days 1, 3, 5, and 7, with a booster every 5 years
– Minimal age for vaccination is 6 years

20. Typhoid vaccines
Vi CPS
• Parenteral vaccine consisting of purified vi
polysaccharide from the bacterial capsule
• Given in 1 dose, with a booster every 2 years
• Minimal age for vaccination is 2 years
Meta-analysis of vaccine trials comparing whole-cell
vaccine, ty21a, and vi CPS in populations in endemic
areas indicates
• All three vaccines are similarly effective for the first year
• 3-year cumulative efficacy of the whole-cell vaccine
(73%) exceeds both ty21a (51%) and vi CPS (55%)

21. Typhoid vaccines
• Typhoid vaccine is not required for international travel,
but recommended for travellers to moderate to high
risk areas (Asia, Africa, the Caribbean, and Central and
South America)
• Typhoid vaccine should be considered even for persons
planning <2 weeks of travel to high-risk areas
• laboratory workers who deal with S. typhi and
household contacts of known S. typhi carriers
• Immunization is not recommended for adults residing
in typhoid-endemic areas or for the management of
persons who may have been exposed in a commonsource outbreak