Download Evaluation Of Typhoid Assay For Rapid Diagnosis Of Typhoid

Correspondence
Evaluation of Typhoid Assay for Rapid
Diagnosis of Typhoid Fever
Sir,
Typhoid fever remains a major public health risk with
more than 13 million cases occurring annually in Asia
alone. Delay in diagnosis and institution of appropriate
therapy especially with emergence of multi-drug
resistant strains of Salmonella typhi, can be associated
with significant morbidity and mortality may
significantly increase the risk of adverse outcome.
Traditionally, the isolation of S. typhi remains the gold
standard for diagnosis but, the Widal test continues to
be the most asked for test, despite numerous problems
in the standardization and interpretation.1 The dot
enzyme immunoassay for detection of serum antibodies
to S. typhi is rapid, simple and can be interpreted
visually.2 The present study was carried out to evaluate
the typhidot test in comparison with blood culture and
the Widal test in patients admitted in PGIMER,
Chandigarh with a clinical diagnosis of enteric fever. In
50 consecutive patients with S. typhi isolated in blood
culture, Widal test and dot EIA were performed. A control
group of 50 patients with unrelated complaints were
included. The Widal test using in-house S. typhi antigens
was considered positive in a single serum sample when
the S. typhi H antibody titre was ≥ 320 and O antibody
titer was ≥160. The Typhidot test (Malaysian
Biodiagnostic Research SDN BDH, Kuala Lumpur,
Malaysia) which detects IgM and IgG antibodies against
S. typhi by using a specific antigen was performed
according to manufacturer’s instructions. The Widal test
in single serum sample was positive in 30 (60%) blood
culture positive patients and was negative in all 50 cases
in the control group. IgG and/or IgM was detected by
the typhidot test in 48 (96%) blood culture positive
patients and 7 controls. Both IgG and IgM could be
detected in 15 patients whereas only IgM could be
detected in 30 and only IgG in three. Neither IgG nor
IgM could be detected in two patients with S. typhi
isolation in blood culture. Presence of IgM was a more
sensitive indicator, with 45 (90%) being positive for IgM
and 18 of 50 (36%) being positive for IgG. Widal test was
found to be 60% sensitive and 100% specific whereas
Typhidot was 96% sensitive and 86% specific when
compared to blood culture. Typhidot had a very high
negative predictive value of 95.55% and positive
predictive value of 87.27%. The diagnostic value of Widal
in single serum samples remains a contentious issue.
The sensitivity of the typhidot test is much higher than
the Widal test and is sensitive even in fevers of short
duration.3 The high NPV (95.55%) of the test even in a
highly endemic area is an advantage and can be
© JAPI • VOL. 54 • FEBRUARY 2006
successfully used even in low-incidence populations.
The Typhidot offers advantages of increased sensitivity,
rapidity, early diagnosis and simplicity over the Widal
test. Culture isolation remains essential especially for
antibiotic susceptibility testing and serological tests for
the diagnosis of typhoid fever can be used in conjunction
with culture.
S Sethi, Shalu Sharma, Anindita Das, P Ray,
A Bhalla*, Meera Sharma
Department of Medical Microbiology and *Internal Medicine,
Postgraduate Institute of Medical Education and Research,
Chandigarh – 160 012, India.
Received : 18.5.2005; Revised : 13.10.2005;
Accepted : 17.11.2005
REFERENCES
1.
Rodrigues C. The widal test – More than 100 years old:
Abused but still used. J Assoc Physicians India 2003;51:7-8.
2.
Gasem MH, Smits HL, Goris MGA, Dolmans WMV.
Evaluation of a simple and rapid dipstick assay for the
diagnosis of typhoid fever in Indonesia. J Med Microbiol 2002;
51:173-7.
3.
Bhutta ZA, Mansur AN. Rapid serologic diagnosis of pediatric
typhoid fever in an endemic area: a prospective comparative
evaluation of two dot-enzyme immunoassays and the Widal
test. Am J Trop Med Hyg 1999;61:654-7.
Spectrum of Hemoglobinopathies in the
State of Orissa : A Ten Years Cohort Study
Sir,
I read the paper ‘Spectrum of Hemoglobinopathies in
the state of Orissa: a ten year cohort study’. The Regional
Medical Research Center at Bhubaneswar though meant
to cater facilities for population screening and provide
diagnosis to referred cases from all over the state of
Orissa, in reality gets cases only from adjoining districts.
In the mentioned study too the author has got only a
handful of cases from the hot bed of
Hemoglobinopathies i.e. Western Orissa comprising of
Sambalpur, Jharsuguda, Sundergarh, Bargarh, Bolangir
Deogarh, and Baudh districts. The Departments of
Medicine and Pathology at VSS Medical College Burla,
a few private clinics and most notably the Rotary Sickle
Cell Project at Sambalpur is doing exemplary service in
the diagnosis and counseling of patients suffering from
the disease which is unfortunately rife in this region.
The Rotary Project which is in operation for the last six
years has tested in excess of 14,000 samples of blood
and has detected the disease in 4800 of them. Readers
should not carry home the false impression that Sickle
Cell disease is mostly seen in coastal and central districts
of Orissa and seen predominantly in the Khandayat
caste. The disease is in fact endemic in the Western belt
of this state with Chasas and Agharias the most affected.
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159
The Regional Medical Research Center is free to come
over here to verify our facts and should reopen their
center in Western Orissa if they actually want cater to
the people of Orissa.
AK Singh
Consultant Physician Diabetologist, The Rotary Sickle Cell
Project, Mediclinic, Golebazar, PO Sambalpur - 768 001, Orissa.
Received : 14.12.2005; Accepted : 20.1.2006
Reply from the Author
Sir,
I appreciate Dr. AK Singh’s interest in the above
article, who has raised his concerns about the
hemoglobinopathies especially the sickle cell disease in
Western Orissa.
The primary objective of the present study was to find
the pattern of hemoglobinopathies in the suspected
referred cases from all over the state of Orissa, which
revealed that the sickle cell hemoglobinopathy is the
major genetic burden and health problem in comparison
to other hemoglobinopathies in the sate. This finding is
not at variance from our earlier study1 carried out at the
hub, i.e. Field Station of Regional Medical Research
Centre (ICMR) located at that time at VSS Medical College
Hospital, Burla in Sambalpur district of Orissa, the so
called “the hot bed of hemoglobinopathies, i.e. Western
Orissa comprising of Sambalpur, Jharsuguda,
Sundargarh, Bargarh, Bolangir, Deogarh, and Baudh
districts”. Therefore, the present study does not give any
wrong impression so far sickle cell disease is concerned
in the Orissa state; whether you have handful of cases
or much larger sample, depends upon the interpretation
of the results. However, the author does agree that the
larger the sample size, the better it is. Further, the
hemglobinopathies are common in Orissa.
The present study as well as our previous studies2-8
has already shown the high occurrence of sickle cell
disease in Central, Western and Southern Orissa. Kar9
has also drawn similar conclusions. The study gives
new information that the sickle cell disease is not
confined to Western Orissa only but it has penetrated
the central as well as coastal region of Orissa, contrary
to what Dr. AK Singh and many other workers believed.
Again, the sickle cell disease is not confined only to
Agharias and Chasa communities of Western Orissa. It
may be noted, however, there are several other
communities.2-4,6,7,10 in Western Orissa, which are at much
more higher risk and are afflicted with the sickle cell
disease. The Khandayat caste of coastal Orissa, which
is either an offshoot of Chasa or Kshatriya community
of Western Orissa, is at high risk of sickle cell disease as
well as for beta-thalassemia syndrome. It has been noted
that, in fact, Chasa is not a name of the community or
ethnic group rather it is a farming or agricultural
community (occupational name), and at different regions
160
or places the people practicing the same occupation are
known by different names in Orissa. The author does
not believe that readers would get the false impression.
The author is aware that there are several government
institutions including the VSS Medical College at Burla/
District Headquarters Hospitals/State Units/Non
Governmental Organisations (NGOs)/Private
Diagnostic Centres/Rotary Club/Private Clinics, etc.
which are providing services for diagnosis, treatment
and counseling to patients suffering from sickle cell
disease in Western Orissa.
The Regional Medical Research Center (RMRC) at
Bhubaneswar is not meant for only catering facilities for
population screening and providing diagnosis for
referred cases from all over the state of Orissa, but has
much wider mandate than has been pointed out by Dr.
Singh and is beyond the scope of this paper.
The treatment of the sickle cell disease patients is a
matter for the State. The research mandate and
responsibilities of the RMRC, therefore, should not be
misunderstood. Moreover, this article does not
necessarily reflect the policy aspects of RMRC.
RS Balgir
Deputy Director (Senior Grade) and Head, Division of
Human Genetics, Regional Medical Research Centre
(ICMR), Chandrasekharpur, Opp. Kalinga Hospital,
Bhubaneswar - 751 023.
Received : 14.1.2006; Accepted : 20.1.2006
REFERENCES
1.
Balgir RS. Pattern of hemoglobinopathies in the pediatric
age group of Orissa. Indian Practr 1994;47:189-93.
2.
Balgir RS. Geographical and caste-wise distribution of sickle
cell hemoglobinopathy in Orissa. Man and Life 1996;22:14956.
3.
Balgir RS. Sickle cell hemoglobinopathy in scheduled castes
and scheduled tribes of Orissa. Medicine and Surgery
1994;32:11-4.
4.
Balgir RS. Genetic dimension of sickle cell hemoglobinopathy
among five scheduled caste populations in Orissa, India.
Indian Practr 2002;55:503-14.
5.
Balgir Rs. Population, ecology and epidemiology of the sickle
cell disease in Orissa. J Hum Ecol 1995;6:273-6.
6.
Balgir RS. Health care strategies, genetic load, and prevention
of hemoglobinopathies in tribal communities in India. South
Asian Anthropologist 2004;4:189-98.
7.
Balgir RS, Dash BP, Murmu B. Blood groups,
hemoglobinopathy and G-6-PF deficiency investigations
among fifteen major scheduled tribes of Orissa, India.
Anthropologist 2004;6:69-75.
8.
Balgir RS. The spectrum of hemoglobin variants in two
scheduled tribes of Sundargarh district in North-Western
Orissa, India. Ann Hum Biol 2005;32:560-73.
9.
Kar BC. Sickle cell disease in India. J Assoc Physicians India
1991;39:954-60.
10. Balgir RS, Mishra RK, Murmu B. Clinical and hematological
profile of hemoglobinopathies in two tribal communities of
Sundargarh district in Orissa, India. Int J Hum Genet
2003;3:209-16.
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© JAPI • VOL. 54 • FEBRUARY 2006