COMMUNITY MEDICINE

1. TYPHOID

2. TYPHOID
• Typhoid fever is due to systemic infection mainly by Salmonella
typhi
• Salmonella typhi infection is found only in men
• The disease is clinically characterized by a typical
continuous fever for 2-3 weeks, with relative bradycardia with
involvement of lymphoid tissues and considerable
constitutional symptoms
• The term “ENTERIC FEVER” includes both typhoid and para
typhoid fevers
• The disease may occur sporadically, epidemically or
endemically

3. EPIDEMIOLOGICAL DETERMINANTS
• AGENT:
1. Salmonella typhi is the major cause of entric fever
2 S.para A & S.para B are relatively infrequent
• S.typhi has three main antigens : O, H & Vi and a number of
phage types
• S.typhi survives intra cellularly in the tissues of various organs
• It is readily killed by drying, pasteurization and common
disinfectants
• The factors which influence the onset of typhoid fever in man
are the infecting dose and virulence of the organism

4. TYPHOID BACILLI

5. • RESERVOIR OF INFECTION:
• Man is the only known reservoir of infection (via cases & carriers)
• CASES: A case is infectious as long as bacilli appears in stools or
urine
• CARRIERS: The carriers may be temporary (incubatory,
convalescent) or chronic
• Convalescent carriers excrete bacilli for 6-8 weeks (after which their
numbers diminish rapidly by the end of three months)
• Persons who excrete bacilli for more than one year are after
clinical attack are called chronic carriers
• In most chronic carriers the bacilli exists in gall bladder and in the
billiary tract. A chronic carrier may excrete the bacili for several
years (may be as long as 50 years)

6. • A famous case of “Typhoid Mary” who gave raise to 1300
cases in her life time is an example for a chronic carrier
state
• Faecal carriers are more common than urinary carriers

7. SOURCE OF INFECTION
• The primary sources of infection are faeces and urine of
cases or carriers
• The secondary sources include contaminated water, food,
fingers and flies
• HOST FACTORS
• AGE: Typhoid fever may occur at any age
• GENDER: Males are more affected than
females

8. • IMMUNITY:
• All ages are susceptible to infection
• The host factors that contributes to resistance to the bacilli
are gastric acidity & local intestinal immunity

9. ENVIRONMENTAL & SOCIAL FACTORS
• Enteric fevers are observed all throughout the year
• The peak incidence is reported during July-September
• Vegetables grown in sewage farmlands or washed in
contaminated water are positive health hazard
• Typhoid bacilli grow rapidly in milk without altering in
taste or appearance in anyway, in which case
ingestion of such raw milk poses a threat to the
consumer

10. • These factors are compounded by such social factors as
pollution of drinking water supplies, open air defecation and
urination, low standards of food and personal hygiene and
health ignorance
• Therefore typhoid fever may be regarded as an index of general
sanitation in any country

11. INCUBATION PERIOD
• Usually 10-14 days
• But the it can be as short as 3 days or as
long as 3 weeks, depending on the dose of
bacilli ingested

12. MODE OF TRANSMISSION
• Typhoid fever is transmitted via the
faecal-oral route or urine- oral routes
• This may take place directly through
soiled hands contaminated with
faeces or urine of cases or carriers
or indirectly by the ingestion of
contaminated water, milk, food or
through flies

13. DYNAMICS OF TRANSMISSION

14. CLINICAL FEATURES
• The onset is insidious, but in children may be abrupt with chills
and high fever
• During the prodromal stage , there is malaise, headache, cough
and sore throat often with abdominal pain and constipation
• The fever ascends in step ladder fashion
• After about 7-10 days, the fever reaches a plateau and the
patient looks toxic appearing exhausted and often prostrated
• There may be marked constipation, especially in the early stages
or “pea soup diarrhoea”

15. • There is marked abdominal distension
• There is leukopenia and blood, urine and stool
culture is positive for salmonella
• If there are no complications the patient’s condition
improves over 7-10 days
• However relapse may occur for up to 2 weeks after
termination of therapy
• During early phase, physical findings are few
• Later splenomegaly, abdominal distension and
tenderness, relative bradycardia, dicrotic pulse and
ocassionaly meningsmus appear

16. • The rash (rose spots)commonly appear during the second
week of the disease
• The individual spot , found principally on the trunk, is a pink
papule 2-3 mm in diameter that fades on pressure. It
disappears in in 3-4 days

17. • Serious complication occur in up to 10 percent of patients
(especially those who have been ill for longer than 2 weeks
and who have not received proper treatment)
• Intestinal haemorrhage is manifested by a sudden drop in
temperature and signs of shock, followed by dark or fresh
blood in the stool
• Intestinal perforation is most likely to occur during the
third week
• Less frequent complications are urinary retention,
pneumonia, thrombophlebitis, myocarditis, psychosis,
cholecystitis, nephritis and oeteomyelitis

18. LABORATORY DIAGNOSIS
• MICROBIOLOGICAL PROCEDURES
The definitive diagnosis of typhoid fever depends on the
isolation of the bacilli from blood, bone marrow and stools.
Blood culture is the mainstay of diagnosis of this disease
SEROLOGICALPROCEDURE
• Felix-Widal test measures agglutinating antibody levels
against O & H antigens
• Usually “O” antibodies appear on day 6-8 and “H” antibodies
on day 10-12 after the onset of disease

19. • The test is usually performed on an acute serum (at first
contact with the patient)
• The test has moderate sensitivity and specificity
• It can be negative up to 30% of culture – proven case of
typhoid fever
• This may be because of prior antibiotic therapy, that has
blunted the antibody response

20. NEW DIAGNOSTIC TESTS
• The IDL tubex test can detect specific IgM
antibodies in samples to S. Typhi liposaccharide
(LPS) antigen and the staining of bound antibodies
by anti-human IgM antibody conjugated to colloidal
dye particles

21. DIAGNOSIS REGIMEN

22. CONTROL OF TYPHOID FEVER
• The control or elimination of the typhoid fever is
well within the scope of modern public health
• There are generally three lines of defence against
typhoid fever:
• 1. Control of reservoir
• 2. Control of sanitation
• 3. Immunization

23. 1.CONTROL OF RESERVOIR
• The usual methods of control of reservoir are their identification,
isolation, treatment & disinfection
• CASES: EARLY DIAGNOSIS –This is of vital importance as the
early symptoms are non-specific
• Culture of blood and stools are important investigations in
the diagnosis of cases
• NOTIFICATION:
Notification must be done in areas where it is mandatory
ISOLATION:
Since typhoid is an infectious disease the cases are to be
transferred to hospital
As a rule cases should be isolated till three bacteriologically
negative stools and urine reports are obtained on three separate
days

24. TREATMENT
• Flouroquinolones are widely regarded as the drug of
choice for the treatment of of typhoid fever

25. • They are relatively inexpensive and well tolerated and more
reliably and effectively than chloremphenicol, ampicillin,
amoxicillin, and trimethoprim & sulphamethoxazole
• Patients seriously ill and profoundly toxic should be given
Inj of hydrocortisone 100 mg daily for 3-4 days
• DISINFECTION: stools and urine are the sole sources f
infection. They should be received in in closed containers
and disinfected with 5% cresol for at least 2 hours
• All soiled clothes and linen should be soaked in a
solution of 2% chlorine and be stream sterilized
• Doctors and nurses should disinfect their hands

26. FOLLOW UP
• Examination of stools and urine should be should be done
for S.typhi 3-4 months after discharge and again 12 months
to prevent development of carrier state
• CARRIERS
• Since carriers are the ultimate source of infection, their
identification and treatment is one of the most radical ways
of controlling typhoid fever
• The following are the measures recommended:
• IDENTIFICATION: Carriers are identified by cultural and
serological examinations. Duodenal drainage establishes
the presence of salmonella in the biliary tract of carriers
• The antibodies are present in about 80% of chronic carriers

27. TREATMENT OF CARRIERS:
• The carriers should be given an intensive course
of ampicillin or amoxycillin (4-6 g a day) together
with probenecid (2g/day) for 6 weeks

28. • These drugs are concentrated in the bile
and may achieve eradication
• Chloromycetin is considered worthless for
clearing the carrier state

29. SUREGERY
• Cholecyctectomy with concomitant
ampicillin therapy has been regarded as
the most successful approach to the
treatment of carriers
• Urinary carriers are eassy to treat, but
refractory cases may need nephrectomy
when one kidney is damaged and the
other is healthy

30. • SURVEILLANCE:
• The carriers should be kept
under surveillance. They
should be prevented from
handling food, milk or water
for others

31. HEALTH EDUCATION
• Health education regarding washing of hands with soap after
defecations or urination and before preparing food is an
essential element
• In short, the management of carriers continues to be an
unsolved problem
• This is the crux of the problem, in the elimination of typhoid

32. CONTROL OF SANITATION
• Protection and purification of drinking
water supplies, improvement of basic
sanitation and promotion of food
hygiene are essential measures to
interrupt transmission of typhoid fever

33. IMMUNIZATION
• Immunization is a complimentary approach in the
prevention of typhoid
• It yields the highest benefit to the money spent
• Immunization against typhoid does not give 100%
protection, but it definitely lowers both the incidence
and seriousness of the infection
• It can be given at any age upwards 2 years

34. • Immunization is recommended to those who live in endemic
areas, house hold contacts and groups at risk of infection such
as school children and hospital staff, travellers proceeding to
endemic areas and those attending melas and yatras
• ANTI TYPHOID VACCINES
1. Vi polyssaccharide vaccine
2. The Type 21a vaccine

35. Vi POLYSSACCHARIDE VACCINE
• The vaccine is composed of purified Vi capsular
polysaccharide from the Ty2 S typhi strain and elicits a T-cell
independent IgG response that is not boosted by additional
doses
• The vaccine is administered sub cutaneously or intra
muscularly . The target value of each single human dose is
about 25 micro gram of antigen
• The vaccine is stable for 6 months at 370 C and for 2 years at
220 C
• The recommended storage temperature is 2-8oC.The Vi vaccine
does not elicit adequate immune responses in children aged
less than 2 yrs
• Only one dose is required and the vaccine confers
protection after 7 days of vaccination

36. • Tomaintain protection revaccination is
recommended every three years.
• The vaccine can be co- administered with other
vaccines (such as yellow fever, and hepatitis A and
with routine childhood vaccinations)
• No serious adverse events and minimum of local
effects are associated with Vi vaccination
• There are no contra indications to the vaccine other
than previous hypersensitivity reaction to vaccine
components

37. THE TYPE 21a VACCINE
• Is an orally administered live attenuated Ty2 strain of S.typhi. The
lyophilized vaccine is available as enteric coated capsules
• The vaccine has to be stored at 2-80C, it retains potency for
approximately 14 days at 250 C
• The capsules are licensed for use in individuals aged above 5 yrs
• The vaccine is administered every other day (on 3 and 5 day) a 3-
dose regimen is recommended
• Protective immunity is achieved 7 days after the last dose
• The recommendation is to repeat the series every 3 years for
people living in endemic areas and every year for individuals
travelling from non endemic to endemic areas

38. TYPE 21 a
VACCINE