Download EPIDEMIOLOGY & CONTROL OF TYPHOID FEVER

EPIDEMIOLOGY &
CONTROL OF
TYPHOID FEVER
DR.AWATIF ALAM
IDENTIFICATION:
(Enteric Fever)
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Systemic bacterial disease
with insidious onset of sustained fever
headache, malaise, anorexia
relative bradycardia,
Splenomegaly
rose spots on trunk
constipation (more commonly than diarrhoea)
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involvement of lymphoid tissues.
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Many mild and atypical infections
may occur,
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Ulceration of peyre’s patches in
ileum can result in intestinal
haemorrhage or perforation
( in about 1% of cases).
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C.F.R. :
“dropped from 10% to 1% with
antibiotic therapy.”
DIAGNOSIS:
Typhoid bacilli can be isolated :
- from blood, early in disease,
- from urine &/ faeces after Ist week
- Agglutination reaction after 2nd week.
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Infectious Agent:Salmonella Typhi – (the typhoid bacillus)
distinguished types – phage typing
(of value in epidemiological studies).
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Occurrence:Worldwide.
(multiple resistant strains in Asia
and Middle East )
Reservoir:
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Man ( as patients & or carriers*)
Family contacts may be transient carriers.
Faecal carriers are more common than
urinary carriers,
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Long-term carriers frequently present
with chronic typhoid cholecystitis.
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Urinary carriers are frequently seen in areas
where schistosomiasis hematobium
infections also occur.
Mode of Transmission:
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Food and water contamination:
by faeces or urine of a patient or carrier.
examples : - Shellfish
( taken from sewage contaminated beds ),
- raw fruits, vegetables,
- milk ,
- products contam. by hands
(of carriers or missed cases),
are imp. vehicle in many parts of world.
Flies can infect foods:
(in which organisms may multiply to achieve an
infective dose).
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Incubation period: 1-3 weeks
(depends on size of infecting dose)
Period of communicability:
- as long as bacilli appear in excreta
(usually from Ist wk. throughout convalescence),
2-5% of cases will become permanent carriers.
Susceptibility and resistance:- Susceptibility is general ,
( but it increases in people with achlorhydria).
- Relative resistance follows:
Clinical or sub-clinical infection,
active immunization.
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Attack rates in endemic areas decreases
with age.
METHODS OF CONTROL :
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Preventive:- (as in cholera).
Encourage brst. + feeding for infants.
Instruct pts., conval., and carriers in
personal hygiene.
Educate general public and esp. food
*”certificate”handlers in the need for
personal cleanliness (including attendants
of pts. Or children).
Exclude infected persons from handling
food.
Imm. – not routinely recommended.
Control of pts. and contacts:RLHA
 Isolation with enteric precautions.
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Concurrent disinfection (of faeces, urine
and soiled articles).
 Investigation of contacts and source of
infection.
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*- Specific Rx: chloramphenicol
( of choice for acute cases )
Food poisoning&
FOOD INTOXICATION
(Occur through consumptn Of contaminated
food or water).
I.d:- “Not an infection”,
- it’s rather an intoxicatn.,
-of abrupt onset with severe nausea,cramps
and vomiting.
- prostration, (often accomp. by diarrhea*),
- subnormal temperature,
- hypotension
- death – rare.
- duration of illness
(commonly not > 1-2 days)
2. Toxic Agent:
- Several enterotoxins of:
staphylococcus aureus,
“ stable at boiling temperature”.
(staph. multiply in food and produce
their toxins).
It is the most common among all
types of food poisoning.
3.I.P.:30 mins. – 7 hrs., usually 2-4 hrs.
bet. eating food and onset of symptoms
Note:-Organisms can exit:
- in nasal secretions,
- on the skin,
- under the nails of a cook.
4.Susceptibility: General,
depending on exposure.
METHODS OF CONTROL
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Notification: – R L H A.
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Send remains of food (and vomit)
for laboratory investigation.
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Health education, especially
among food handlers.
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Proper refrigeration of food.
“Other types of Food Poisoning”
A. Salmonellae food infection :
-through ingestion of contaminated
food with animal excreta e.g. rodents.
Signs & Symptoms:
- Fever,
- Abdominal Pain
- vomiting and diarrhea.
I.P.:6-48 hrs.
Prevention: - Sanitatn.
- Health education.
B. Botulism:
I.d.: Severe intoxicatn. resulting from
ingestn. of toxin performed in
contamin. food and not from toxin
produced in the gut.
Toxic Agent:Clostridium botulinum toxins.
Note:
The illness is charact. by manifestatns. Related to
the nervous syst. (esp. cranial ns.) e.g.
ptosis, visual difficulty, dry mouth. Then such
symptoms may be followed by flaccid
paralysis.
Vomiting and diarrh. may be present initially.
Note:
The illness is charact. by manifestations
related to:
- the nervous system (esp. cranial ns.)
e.g. - ptosis,
- visual difficulty,
- dry mouth.
- may be followed by flaccid paralysis.
- Vomiting and diarrhea
( may be present initially).
* Fever absent
(unless a complicating infection occur).
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Occurrence: World wide
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Reservoir: Soil, intestinal tract of animals.
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I.P.:12-36 hrs. (after eating contam. food).
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Suspect.: General.
 Methods of Control:- Ensure effective control of processing and preparation
of commercially canned and preserved foods.
- Educate housewives regarding proper canning
procedures (e.g. proper time, pressure, temp. req. to
destroy spores and the need for adequate refrig. of
food).
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RLHA
Investigate contacts and source of toxin.
The golden rules for prevention of food
poisoning
1- Choose foods processed for safety.
2- Cook food thoroughly.
3- Eat cooked food immediately.
4- Store cooked food carefully.
5- Reheat cooked food thoroughly.
6- Avoid contact between cooked and raw
food.
7- Wash hands repeatedly. using lots of
friction
W—warm
A—and
S—soapy
8- Keep all kitchen surfaces meticulously clean. Wash
dishes and utensils after contact with raw meat or
eggs.
9- protect foods from
insects,
rodents and other
animals.
10- use safe water.
Keep hot food hot and
cold food cold.