This is a slide presentation on the Epidemiology of Typhoid fever.

1. Epidemiology of Typhoid
fever
Dr. Arindam Maiti
3rd Year Post-Graduate Resident
Department of Community Medicine
NSCB Medical College, Jabalpur (M.P.)

2.  Introduction
 History
 Problem statement
 Epidemiological determinants
 Incubation period
 Modes of transmission
 Clinical features
 Laboratory diagnosis
 Control

3. Enteric fever (typhoid and Paratyphoid fever)
- Sporadic
- Epidemic
- Endemic
 Continuous fever (3-4 weeks)
 Relative Bradycardia
 Lymphoid tissue involvement
 Constitutional symptoms
* Septicemia, Gastroenteritis or Carrier state

4. Typhos - “cloud/smoke” - madness (ancient)
 1829- Louis distinguished typhoid from typhus.
 1839- Schonlein - lesions in Payer’s patches and Mesenteric
lymph nodes - Typhoid.
 1856- Budd- transmission through excreta of patients.

5. 1880- Eberth - demonstration of bacilli in lymphoid tissues.
1884- Gaffky-grew organisms in pure culture
1890- Pfeiffer, Wright and Kolle - vaccination experiments.
1975- Germanier and Furer- developed vaccine.

6. • Areas of poor water supplies and sub-standard sanitation.
• Uncommon in developed countries (acquired abroad or imported by
immigrants).
• Drastic reduction from 1940s after invention of antibiotics.
World:
• Public health problem – developing areas of Asia , Africa and Latin
America.
• As per WHO- 11-20 million cases with 128,000-161,000 deaths annually
noted.*
• From 1950 to 1989, resistance against antibiotics were in rising trend in
Asia and Middle East (India and Pakistan were mostly affected).*
* WHO Fact Sheet, 31st Jan. 2018

7. • More than 50% of cases in South-east Asia – Resistant cases.*
• Resistant cases – complications and death, especially in < 2 years.
*WHO (2018), The World Health Report, Report of the Director General WHO

8. India:
• 2.30 million cases with 399 deaths (2018).*
• Maximum cases with deaths noted in the states of Uttar Pradesh (764,272;224),
followed by West Bengal (251,296;17).*
• In Madhya Pradesh- approx 69,000 cases(2021) from 85,810 cases(2020).#
• Largest known outbreak till date was noted in Sangli, Maharashtra in 1975-1976,
where almost 9000 cases were noted.
• 1st Antibiotic -resistant type of outbreak noted in Kerala in (1972-1978)
• From 1980s onwards antibiotic-resistant outbreak were noted in many regions.
* Govt. of India (2019), National Health Profile 2019, DGHS, Ministry of health and Family Welfare, New Delhi
# https://www.statista.com-statitistics (2021)

9. Agent
 Salmonella typhi
 Salmonella paratyphi A and C, B (infrequent)
 Salmonella typhimurium and Salmonella enteritidis (animal and human)
• Gram-negative, facultative aerobe, motile-peritrichous flagella
• 3 antigens ( O, H and Vi )
• Phage typing – epidemiological tool- epidemics.

11. • Can be killed by heating at 60℃ for 15 minutes and by formalin,
chlorine/bleaching powder and KMno4.
• Human intestine- commensal, survive intracellularly in spleen and
kidney.
• Disease process - endotoxin.
• Survives for 15-20 days in evironment.
• Infective dose - 10^2 - 10^5 bacilli.

12. • Reservoir
Man (cases, carriers)
- mild/missed/severe.
-a case/carrier infectious as long as bacilli appears in stool/urine.
• Carriers
1. Temporary (incubatory, convalescent)
a) Convalascent – excretion of bacilli for 6-8 weeks.
b) About 4 %- excretion till end of 3 months.
c) About 3 %- average carrier state for 1 year.
2. Chronic - excretion of bacilli for > 1 year (2-5%)
* In chronic states Bacilli persisits in Gall bladder and Biliary tract.
Eg. :- Typhoid Mary - 1300 cases lifetime.

13. Fecal carriers > Urinary tract carriers.
Urinary tract carriers - Complications.

14.  Host factors
• Age
-any age
-5-19 years - highest
-Annual incidence of confirmed cases - 180-494/1,00,000
population (5-15 yrs.)
- > 20 years - incidence is rare due to immunity from clinical /sub-
clinical cases.
• Sex :
-male>female (5:1)
-female>male (in carrier state, 5:1)

15. Immunity
 Antibodies against somatic antigen (O-antigen) > flagellar antigen (H-
antigen)- Typhoid Cases.
 Antibodies against flagellar antigen (H-antigen) > somatic antigen (O-
antigen)- Immunized cases.
 Antibodies against Vi-antigen (capsular) - carriers.
 Cell-mediated Immunity plays an important role.
 2nd attack > 1st attack (Large solid dose)
* Resistance - Gastric acidity and local intestinal immunity.

16.  Environmental Factors
Peak - Monsoons (July-September)
Rise in fly population.
Sub-tropical countries (warm environment).
Do not multiply in water.
Perishes within 48 hours, few survive for 7 days.
Survives well in food.
Survives for a month in ice and ice-cream, while 70 days in irrigated
water/sewage in winters and half of that during summer.
Multiplies rapidly in milk without altering its taste and appearance.
Vegetables grown in sewage water.

17.  Social factors
 Drinking water pollution
 Open field defecation and urination
 Poor health and food hygiene
 Health ignorance
 Poverty

18.  Incubation period
 10-14 days - Salmonella typhi
 4-5 days- Salmonella paratyphi
 But can range from 3 days to 3 weeks (Dose of bacilli ingested)

19. Faeces,
urine from
cases or
carriers
Food
Raw or
Cooked
Mouths of
well
persons
Water
Soil
Flies
Fingers
SOCIAL FACTORS
ECONOMIC
FACTORS
CULTURAL
FACTORS
QUALITY OF LIFE
Faeco-oral /Urino-oral route

20. • Insidious in onset, abrupt in children
• Prodromal stage- Fever- step-ladder fashion, malaise, headache, cough, sore
throat, joint pain, vomitting, abdominal pain with constipation.
• Early stage- marked constipation, pea-soup diarrohea.
- leukopenia
- Blood culture - positive.
- Few clinical signs (abdominal signs- rare)
• Late stage-splenomegaly, abdominal distension with tenderness,
relative bradycardia with occassional meningismus.
-Rash (Rose spots) - 2nd week of disease- trunk- 2-3 mm in
diameter- pink papule- fades on pressure- disappears in 3-4 days.

23. • Stool and Urine culture-Positive
• After 7-10 days-plateau phase- toxic appearance.
• Complications - > 7-10 days- 10%- no proper treatment
- Intestinal hemmorahage (hypovolemic shock with
dark colour stool/fresh blood in stool)
- sudden hypothermia.
- Intestinal perforation (3rd week)
- Rare (urinary retention, pneumonia, thrombophlebitis,
myocarditis, psychosis, cholecystitis, nephritis,
osteomyelitis)
• Relapse - upto 2 weeks after termination of therapy

24.  Case fatality rate
 1-4%
 Children aged < 4 years being 10 times higher than in older children.
 Untreated - 10-20%

25. Microbiological
 Isolation of bacilli from blood, bone marrow and stools.
 Blood culture-mainstay.
Serological-Felix-Widal test
-Agglutination of antibody levels against O and H antigens.
-O- 6-8 days
-H- 10-12 days
-Negative (30%) - prior antibiotic therapy.
-False positive - cross-reaction with other Enterobacteriacae.
In Malaria, typhus, cirrhosis and bacteraemia due
to other organisms.

27. Blood culture (90%) 1st week Mainstay of diagnosis
Antibodies
(Widal test)(low titre)
2nd week Moderate sensitivity and
Specificity
Stool culture (80%) 3rd week -
Urine test 4th week -

28. Name of test Type of Antibody
detection
Technique Time taken Country
developed
IDL Tubex test IgM antibodies IgM09 few minutes Sweden
Typhidot IgM and IgG
antibodies
against 50 kD
antigen of bacilli
3 hours Malayasia
Typhidot-M IgM antibodies - 3 hours -
Dipstick test IgM antibodies LPS antigen and
staining of bound
antibodies by
anti-human IgM
antibody
conjugated to
colloid dye
particles
- Netherlands

29. Control of Cases
a)Early diagnosis
b)Notification
c)Isolation-2 weeks(prolonged course,Infective cases are treated in hospitals)
-3 negative stool and urine tests for 3 seperate days.
d)Treatment - Drug of choice - Ciprofloxacin/Ofloxacin
-Serious - Injection of Hydrocortisone 100 mg for 3-4 days.
e)Disinfection- 5% cresol for 2 hours (stool and urine, in closed container)
- soiled clothes and linen (soaked in 2% chlorine solution
and steam sterlilized)
.

30. - Hand hygiene by health care workers.
f) Follow - up - 3-4 months after discharge followed by after
12 months.

31. Susceptibility
Optimal therapy Alternative effective drugs
Antibiotic
Daily dose
(mg/kg)
Days Antibiotic
Daily dose
(mg/kg)
Days
Fully sensitive
Ofloxacin/
Ciprofloxacin
15 5-7
Chloramphenicol
Amoxicillin
TMP-SMX
50-75
75-1000
8-40
14-21
14
14
Multidrug
resistance
Fluroquinolones
or
Cefixime
15
15-20
5-7
7-14
Azithromycin
Cefixime
8-10
15-20
7
7-14
Quinolone
resistance
Azithromycin
or
Ceftriaxone
8-10
75
7
10-14
Cefixime 20 7-14

32. Control of carriers
a) Identification - Cultural and Serological examinations.
-Duodenal drainage (biliary tract)
-Vi antibodies - 80% (chronic)
b) Treatment - Ampicillin/Amoxicillin (4-6 gm/day) with Probenacid
(2 gm/day) for 6 weeks -Eradication - 70%
- Cholecystectomy with Ampicillin therapy ( >80%
successful)
- Intestinal carriers - Resection of loop of gut.
- Refractory cases - Nephrectomy
c) Surveillance - Food,milk or water handling
d) Health education - Hand hygiene and sanitation.

33.  Protection and purification of
drinking water
 Sanitation Barrier-interruption of
modes of transmission
 Health education

34.  Does not give 100% protection, but lowers incidence and seriousness of the
infection.
 Recommended to :-
a) Living in endemic areas
b) household contacts
c) High risk groups (school children, hospital staffs)
d) Migration to endemic areas.
e) Attending melas and yatras.

35. Vi polysaccharide vaccine
a) Type- subunit vaccine, bivalent
b) Strain- Purified Vi capsular polysaccharide from Ty2 S.typhi
strain/S. paratyphi
c) Route- Subcutaneous/Intramuscular route.
d) Storage- 2-8℃.
e) Potency- 6 months at 37℃, 2 years at 22℃
f) Age group - ≥ 2 years
g)Dosage and Schedule - single, revaccination every 3 years.
h) Contraindication - nil
i) Adverse effects - nil

36. Ty21a vaccine
a)Type- whole cell live-attenuated vaccine, lyophilised.
b)Strain- Multiple genes from strain of Ty2 S. typhi
mutated chemically.
c)Route - oral (enteric coated capsules)
d)Storage - 2-8℃
e)Potency - 25℃ for 14 days.
f)Age group - ≥ 5 years
g)Dosage and Schedule - 3 dose regimen, 1st, 3rd and 5th day
- To be repeated every 3 years in endemic
areas.
- Migration.

37. Can be co- administered with other
live vaccines.
h) Contraindication - Proguanil and antibacterial drugs are to be stopped
untill 3 days after vaccination.
- HIV positive patients with symptoms and CD4 count ≤
200/mm3
- Congenital/acquired Immunodeficiency symptoms
- Immunosuppressive therapy
- Acute Intestinal infection
i) Adverse effects- no such.

38. 1.K. Park, Epidemiology of Communicable diseases; Epidemiology of Typhoid
fever. 26th Edition. Park’s Textbook of Preventive and Social Medicine: Bhanot
Publishers (P) Ltd; Jabalpur 2022 : p. 232-7.
2. Kadri A.M., Singh A, IAPSM’S Textbook of Community Medicine;
Epidemiology of Typhoid fever; 2nd Edition. Jaypee Brothers Medical
Publishers (P) Ltd.; 2022. p. 335-9.

39. THANK YOU