*Corresponding Author Address: Prof Dr. Mohammed Sh. Jebur, Institute of Medical Tech. Email: d_mohamed_1959@yahoo.com
World Journal of Pharmaceutical Sciences
ISSN (Print): 2321-3310; ISSN (Online): 2321-3086
Published by Atom and Cell Publishers © All Rights Reserved
Available online at: http://www.wjpsonline.org/
Original Article
Comparison of IFAT, rk39 and PCR for diagnosis of kala-azar in Iraqi children
Basheer Abdullah Naseralla*, Maher Ali Al-Quraishi**, Mohammed Sh. Jebur*
*Institute of Medical Technology and **College of Science / Babylon University, Babylon, Iraq
Received: 05-12-2014 / Revised: 26-12-2014 / Accepted: 26-01-2015
ABSTRACT
A comparative study was carried out through IFAT, rk39 and PCR diagnostic methods for detection of
pediatric visceral leishmaniasis (Kala-azar) in Baghdad hospitals during the period from July 2013 to
September 2014. Blood samples from 178 suspected VL patients were examined by IFAT, rk39 and
PCR. Results of polymerase chain reaction which depending on highly repetitive sequence regions, reported that
only 39 (21.9%) of samples were positive to visceral leishmaniasis and 139 (79.1%) were negative. So that these
results were considered as standard test for IFAT and rk39 test, for that the validity of IFAT according to PCR
technique detected the sensitivity of IFAT was (100%) and specificity (82%) with accuracy (89%). While the
validity of rK39 test according to PCR technique, it was found that the sensitivity of rK39 (97.4%) and
specificity (85.2%) with accuracy (90%).The study concludes that these diagnostic methods had an excellent
ability of discrimination in diagnosis of VL cases.
Key words: Visceral leishmaniasis, IFAT, rk39 and PCR
INTRODUCTION
Leishmaniasis is endemic in 98 countries and
3 territories on five continents; it is estimated that
there are 2 million new cases annually worldwide
and up to 350 million people at risk of the
disease [1,2]. The parasite invades internal organs
such as spleen, liver and bone marrow which
usually with mortality rate almost 100% if left
untreated[3]. The amastigotes stage of the
parasite replicate in macrophages of the
mononuclear phagocyte system and then spread
to the entire reticuloendothelial system resulting
Kala-azar [27]. Laboratory diagnosis is important
for VL because clinical evaluation is not
enough for conclusive diagnosis[4]. The
sensitivity culture and microscopic examination
tends to be low and highly variable, depending
on the number of the parasites in sample and
technical skills of the personnel [5]. Accurate
diagnosis to guide treatment is the first step to
achieve the goal of VL elimination. Up until the
1990’s accurate visceral leishmaniasis (VL)
diagnosis was complex and invasive including
parasitological confirmation by direct
microscopic examination of splenic, lymph gland,
or bone marrow aspirate or culture of the blood,
bone-marrow, lymph nodesor spleen [6]. The rK39
dipstick test is the product of a gene cloned
from Leishmania containing 39 amino acid repeat
conserved among Leishmania species
(7)
.A
recombinant antigen, rK39 has been shown to be
specific for antibodies arising during VL caused by
member of the L. donovani complex. It is highly
sensitive and predictive for onset of acute disease
and evokes high antibody titers of VL patients [8].
The indirect fluorescent antibody (IFA) test is one
of the commonly tests used for anti-leishmanial
antibody detection by using fixe Promastigotes.
The test is based on detecting Ig Gantibodies
against Leishmaniaspp, which are demonstrated in
the serum very early and different stages of
infection but are undetectable up to nine months
after cure [9]. Various PCR amplification targets
nuclear DNA, such as the small subunit ribosomal
RNA gene, internal transcribed spacer regions, the
gp63 gene locus and extra chromosomal DNA
including the repetitive kinetoplast DNA (kDNA)
minicircles [10]. Diagnosis of VL using
conventional PCR methods has advanced technique
that increasing in sensitivity of assay with
optimization of protocols and permitting detection
of parasite even before the appearance any clinical
symptoms, also applicability to wide variety of
clinical material by peripheral blood, lymph node,
bone marrow, serum, skin, and urine. Also analysis
of archival materials like Giemsa stained bone
marrow aspirates, formalin-fixed tissue and skin