Serodiagnosis of typhoid fever

SERODIAGNOSIS OF TYPHOID
FEVER
BY
UDEOGU CHRISTIAN CHIBUZOR

 Typhoid fever also referred to as enteric fever
continues to be one of the leading killers in the
world claiming thousands of lives.
 Worldwide, typhoid fever affects more than
21 million people annually, with about
200,000 people dying from the disease.
 Caused by certain strains of the bacteria
Salmonella usually, Salmonella typhi and
Paratyphi A, B and C.
 Typhoid fever is contracted by drinking water
or eating food contaminated with the bacteria

Some Features of Salmonella
 Gram Negative rod shaped
 Motile with peritrichous
flagella
 Facultative anaerobes
 Possess two (2) Antigenic
structures ‘‘Somatic O antigen
and Flagella H antigen’’.
Source: Centre for Disease Control
and Prevention (CDC), 2013.

 High fever, malaise, headache,
and cough. Rose spots appear
on the lower chest and
abdomen in around a third of
patients.
 Diarrhoea with six to eight
stools in a day and possessing
a characteristic smell.
Liver transaminase are
elevated.
Source: World Health Organisation, 2016
SIGNS AND SYMPTOMS

SIGNS AND SYMPTOMS CONT’D
Respiratory diseases such
as pneumonia and acute bronchitis
Neuropsychiatric symptoms (described as
"muttering delirium" or "coma vigil"), with
picking imaginary objects.
Dehydration
Platelet count goes down slowly and risk of
bleeding rises.

• Spread is by faecal- oral
route through poor
hygiene habits and
public sanitation
conditions, and
sometimes also by flying
insects feeding on feces
and infecting our food.
Transmission
(Source: Yap Kien-Pong et al; 2014)

EPIDELOMOLOGY
Africa
North
America
South
America
Asia
Australia
Europe

 In 2000, typhoid fever caused an estimated 21.7 million
illnesses and 217,000 deaths worldwide. (Crump, J. A., & Mintz,
E. D, 2010).
 In Nigeria, the annual mortality rate per 100,000 people from
typhoid fever in Nigeria has increased by 7.0% since 1990, an
average of 0.3% a year.
 For men, the deadliness of typhoid fever in Nigeria peaks at age
1-4. It kills men at the lowest rate at age 50-54.
 Women are killed at the highest rate from typhoid fever in
Nigeria at age 1-4. It was least deadly to women at age 40-44.
At 5.5 deaths per 100,000 women in 2013, the peak mortality
rate for women was higher than that of men, which was 4.3 per
100,000 men. (Institute for Health Metrics and Evaluation,
2016).
EPIDEMIOLOGY CONT’D

 This presentation will be limited to the widal
method for the serodiagnosis of typhoid fever
LIMITATIONS

 To acquaint the audience with the widal method
of serodiagnosing typhoid fever
AIM

 Principle of the Widal method
 Types of Widal method
 Interpretation of the widal test result
SCOPE

 The principle of widal test is based on specific Antigen and
Antibody interaction.
 It states that If homologous antibody is present in a patients
serum, it will react with the respective antigen in the reagent
and then gives a visible clumping or agglutination.
 The antigens used in the test are Salmonella Typhi Somatic
antigen depicted by the letter “O” and Flagella antigen by the
letter “H”.
PRINCIPLE OF THE WIDAL METHOD

PRINCIPLE OF THE WIDAL METHOD CONT’D
Source: Eberth C. J., 1881

 TILE TEST
 SEMI-QUANTITATIVE METHOD
 STANDARD TUBE TEST METHOD
TYPES OF WIDAL METHOD

 PROCEDURE:
 Using a pasteur pipette, add one drop of the patient serum to
be tested onto eight reaction circles on a tile labelled
according to given antigen solution.
 Add on same tile, one drop each of the Widal TEST antigen
suspension for Somatic ‘O’ and Flagella ‘H’ antigen of
Salmonella typhi and Paratyphi.
 Mix contents of each circle uniformly over the entire circle
with separate mixing sticks.
 Rock the slide, gently back and forth and observe for
agglutination macroscopically within one minute.
TILE TEST

 It is a quick diagnostic test
 It utilizes minute amount of reagents
 It is cost effective
Discrepancies in interpreting result
The serum antibody titre is difficult to determined
ADVANTAGES OF THE TILE TEST
DISADVANTAGES OF THE TILE TEST

 PROCEDURE:
 Pipette one drop of normal saline into the reaction circle and
then place 5, 10, 20, 40, 80 ul of the test sample on the
remaining circles.
 Each of the serum represents an increasing titre value i.e
5 (1/20), 10 (1/40), 20 (1/80), 40 (1/160), 80 (1/320).
 Add to each reaction circle, a drop of the antigen which showed
agglutination with the test sample in the tile screening method.
 Using separate mixing sticks, mix the contents of each circle
uniformly over the reaction circles.
 Rock the slide gently back and forth, observe for agglutination
macroscopically within one minute.
SEMI-QUANTITATIVE METHOD

 PROCEDURE:
 Prepare a set of test tubes for individual antigen. Each set
contains 1- 8 tubes.
 Add 1.9 ml of sterile normal saline to tube no. 1 of each
antigen set while to tube no. 2-8 of all sets add 1 ml of sterile
normal saline.
 To tube No. 1 of all sets add 0.1 ml of test sample to be tested
and mix well.
 Transfer 1 ml of the diluted serum sample from tube No. 1 to
tube No. 2 and mix well.
STANDARD TUBE TEST METHOD

 Transfer 1 ml of the diluted serum sample from tube No. 2 to tube
No. 3 and mix well. Continue this serial dilution till tube No. 7 in each
set of antigen.
 Discard 1.0 ml of the diluted serum from tube No.7 of each set.
 Tube No.8 in all the sets, serves as a negative saline control. Now the
dilution of the serum sample achieved from tube No. 1 to 7 in each
set are 1:20 1:40 1:80 1:160 1:320 1:640 1:1280 while tube no. 8 is
negative control with sterile normal saline.
 Now the dilution of the serum sample achieved in each set is as
follows: Tube No. : 1 2 3 4 5 6 7 8 (control) Dilutions 1:20 1:40 1:80
1:160 1:320 1:640 1:1280.
.
STANDARD TUBE TEST METHOD CONT’D

 To all the tubes (1 to 8) of each set add one drop of the
respective widal test antigen suspension from the reagent vials
and mix well
 Cover the tubes and incubate at 37° C overnight (approximately
18 hours).
 Dislodge the sedimented button gently and observe for
agglutination.

Source:

 It is more accurate than the tile method
 The serum antibody titre can be correctly determined
ADVANTAGES OF THE STANDARD TUBE TEST
DISADVANTAGES OF THE STANDARD TUBE TEST
It is time consuming
It requires the use of a high amount of reagent
It is expensive to manage

 REAGENT TEMPERATURE
 HOMOGENOUS MIXTURE
 CONCENTRATION OF REAGENT TO SERUM SAMPLE
 ROCKING
 TIMING
PRECAUTIONARY MEASURES BEFORE AND
DURING WIDAL TESTING

INTERPRETATION OF THE WIDAL TEST
RESULT

 The titre of the patient serum using Widal test antigen
suspensions is the highest dilution of the serum sample that
gives a visible agglutination.
 A titre >1/80 is considered significant.
 The limitations and problems faced using the widal method
when diagnosing this illness makes it difficult in accurately
confirming a typhoid disease.
INTERPRETATION OF THE WIDAL TEST RESULT CONT’D

 Dutta P, Mitra U, Dutta S, De A, Chatterjee MK, Bhattacharya
SK (2001). "Ceftriaxone therapy in ciprofloxacin treatment
failure typhoid fever in children". Indian J Med Res. 113: 210–
3. PMID 11816954.
 Коваленко А.Н.; et al. (2011). "Особенности клиники,
диагностики и лечения брюшного тифа у лиц молодого
возраста". Voenno-meditsinskii zhurnal. 332 (1): 33–39.
Bhutta ZA, Khan IA, Molla AM (1994). "Therapy of multidrug-
resistant typhoid fever with oral cefixime vs. intravenous
ceftriaxone". Pediatr Infect Dis J. 13 (11): 990–
993. PMID 7845753. doi:10.1097/00006454-199411000-
00010.
REFERENCES

 Cao XT, Kneen R, Nguyen TA, Truong DL, White NJ, Parry CM
(1999). "A comparative study of ofloxacin and cefixime for
treatment of typhoid fever in children. The Dong Nai
Pediatric Center Typhoid Study Group". Pediatr Infect Dis
J. 18 (3): 245–8. PMID 10093945
 Diarrhoeal Diseases (Updated February 2009) at
the Wayback Machine (archived November 2, 2011). World
Health Organization
 "WHO | Typhoid fever". www.who.int. Retrieved 2017-08-10.
REFERENCES

Serodiagnosis of typhoid fever

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