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Research
Article
Bolak and Tebid: Malaria parasites and salmonella species co-infection rate among patients attending the
Buea regional hospital, AJIH 2013, 02: 32-35
Malaria Parasites And Salmonella Species Co-Infection Rate
Among Patients Attending The Buea Regional Hospital,
Cameroon
Blessed S. Bolak1, Patience A. Gana-Tebid 2*
Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Buea, Cameroon
*Corresponding author: Patience A. Gana-Tebid. Email: tepatan@yahoo.com
Key Words: Malaria parasites, Salmonella species, Widal, Stool, Culture, Co-infection.
ABSTRACT
Background
Co-infection of malaria parasites and salmonella species
have been reported in many countries including Cameroon
during the last few decade by the aid of various Methods of
diagnosis. The rates of co-infection are usually
exaggerated. Thus the work aimed at investigating the coinfection rates of malaria parasites and Salmonella species.
Method
A prospective study was carried out in the South western
region of Cameroon, specifically the Buea regional
Hospital, Cameroon. Patients included those clinically
presented with febrile illnesses and suspected for malaria
and or typhoid. Thick and thin film for Malaria parasites
was done alongside widal test and stool culture for
Salmonalla species.
Result
Out of the 136 positive malaria subjects, 88(64%) were
positive for various salmonella antibobies (widal test) and
48 (35%) negative for salmonalla antibody tities by the
widal test. Meanwhile out of the 248 negative malaria
subjects, 154(62%) were positive for salmonalla antibody
and 94(38%) were negative for the salmonalla antibody
(Positive was titre > 1/160). The rate of co-infection was
significantly higher when Salmonella species was
diagnosed by widal (84%) than by stool method (16%). A
correlation coefficient (R=0.05) showed no specific
relationship between malaria parasite load and the level of
Salmonella antibody (widal) and antigen (Salmonella
species).
Conclusion: No correlation between positive malaria cases
and positive salmonella species existed this study.
However, co-infection rates, based on diagnosis of typhoid
and paratyphoid by WIDAL is greatly increased and
reduced based on cultural method. Therefore, a reliable
testing method for salmonella species is an important
indicator for co-infection rates rather than using only
WIDAL test.
diseases have different modes of transmission, they share
some similarity in symptoms [6] and have similar
epidemiology [7, 8 ].As such both diseases can be confused
for the other or can result in co-infection. The high
prevalence of typhoid fever and malaria in the tropics has
made co-infections to be common. However, the actual and
precise underlying mechanisms to explain the association
between malaria and Salmonella species infection is still
uncertain, although there are few postulations which may
explain why malaria may predispose to salmonella
bacteraemia and sepsis [ 9 ].
In most part of the tropic, specific diagnosis of concurrent
malaria and typhoid fever is by microscopy of stained
blood smear and widal test and very rarely, culture [10].
Also, in Cameroon, majority of Community based health
centres lack culture diagnostic facility for identification of
Salmonella species. As such, diagnosis of typhoid fevers is
mainly by the use of Widal test. When the widal test is
used for diagnosing co-infection, rates are usually higher
than culture method [11 ].
Generally the exact rate of co-infection is not generally
known therefore, this study aimed at determining the rate
between malaria parasites and salmonella species in
patients attending the Buea Regional Hospital in
Cameroon.
Methods
Study area and Subjects
The study was carried out in the Buea Regional Hospital,
South West Region of Cameroon,
and included 384
febrile subjects. Blood as well as stool samples were sent to
the Laboratory for the widal and malaria parasite tests by
the attending physician.
Ethical consideration
The study was approved by the Regional Delegation of
Public Health and also by the director of the Buea Regional
Hospital. Informed consent was equally obtained from
every participant.
Laboratory investigation
Four milliliters of blood was drawn by venepuncture from
each person into dry tube. A thin and a thick blood films
were prepared immediately from the blood for malaria
Introduction
Malaria and typhoid fever are a major public health
dilemma in the tropics. However, malaria remains the most
infectious disease in the topics and subtropics of the world
[1, 2, 3]. Similarly, typhoid is also endemic in Africa and
severely affects infants and elderly [4, 5].Though both
Afr. J. of Integ Health Vol 1: No1; 2013
32
Research
Article
Bolak and Tebid: Malaria parasites and salmonella species co-infection rate among patients attending the Buea
regional hospital, AJIH 2013, 02: 32-35
parasite. The serum obtained was later tested against S.
typhi, S. paratyphi A,B and C, for both O and H
antibodies.Sterile labelled specimen containers were also
given to the subjects and they were instructed to collect
their early morning stool specimens. Blood samples and
stool samples were also collected from 52 apparently
healthy individuals as controls.
Parasitological examination
Giemsa-stained thick and thin blood films (3%) were
prepared for each sample and parasitaemia was calculated
per microliter of blood. The stained thick films were
examined microscopically for the presence of malaria
parasites and parasites counted against 100 leucocytes.
Estimation of malaria parasitemia was calculated assuming
a normal leukocyte count of 5400cells/µl of blood set for
healthy patients. Malaria parasites counted on the thick
film were the ring forms, trophozoites and gametocytes.
Thin film was used to confirm the species by observing
parasites inside of the red blood cells. A smear was
considered negative for malaria parasites if no parasites
Malaria Parasites/ul of blood
WBC(5400)
=
Parasite count X Normal
WBC counted (100)
were seen after examining at least 100 microscopic fields.
Positive slides were quantified as follows.
Widal Reaction
The WIDAL (AGAPE) agglutination test was performed
on all blood samples by the rapid slide method. Positive
reactions were followed by a tube agglutination method to
obtain the titres. A positive Widal test was considered for
any serum sample with antibody titre ≥1/160 for the O
antigen of S. typhi and S.paratyphi.
Table 2: Co-infection malaria positives against
Salmonella species of widal test
Salmonella Species
Malaria Positive
(N=136)
Typhi
15(11%)
Paratyphi A
81(60%)
Paratyphi B
34(25%)
Paratyphi C
06(4%)
Total
136
Stool culture
The stool specimens were inoculated into selenite broth
and incubated at 37°C for 24 hours. Then sub-cultured onto
Salmonella Shigella agar (SSA) and incubated at 37°C for
24 hours. All the samples were processed within 2 h of
collection. Colonies were later identified by inoculating on
Kliglar ion agar (KIA), urea broth.
Data Analysis
Chi-square test was used to determine the statistical
significance of malaria and salmonella co-infection and
Afr. J. of Integ Health Vol 2: No1; 2013
statistical differences were considered at a P-value less
than 0.05.
The relationship between malaria parasite counts µl-1 of
blood and Salmonella O and H antibody titres were
determined by carrying out a correlation analysis using the
Microsoft Excel (2007).
Results
The study included 384 patient samples aged between 5
and 80 years (mean = 28 years). Malaria parasites were
found in 136 (35%) samples (mean parasite load =
1.6×104parasites µl-1 of blood). Out of the 136 positive
malaria subjects, 88(64%) were positive for various
salmonella antibobies (widal test) and 48 (35%) negative
for salmonalla antibody tities by the widal test. Meanwhile
out of the 248 negative malaria subjects, 154(62%) were
positive for salmonalla antibody and 94(38%) were
negative for the salmonalla antibody (Positive was titre >
1/160).
Table 3: Comparing Control subjects against malaria
positive patient’s co-infection with Salmonella species
from culture and Widal.
Widal (antibody) Salmonella total
culture
Malaria
114(84%)
22(16%)
136
positive
Control
16(31%)
0 (0%)
subjects
From the table above out of the 384 patient samples
analysed, 88(23%) samples were co-infected with both
malaria and salmonella by the widal test. Antibodies
against salmonella were present in 154(62%) patient
samples which tested negative for malaria. 48 (13%)
malaria samples were negative for antibodies against
salmonella and 94(38%) samples were positive for
salmonella and negative for malaria (Table 1).
The statistical analysis of the data using Chi-square showed
that there was no significant difference between the mean
antibody titres (anti ‘O’ titres) in the malaria and typhoid
patients (p>0.05). Although 62% of malaria positive
samples had detectable levels of antibodies to the somatic
antigen of salmonella species, parasite load and antibody
levels were shown not to be mutually correlated. The
correlation coefficient (r) of 0.05for somatic antigen
indicated that the level of Salmonella antibodies in the
malaria patients was not related to the presence of malaria
parasites. We failed to reject the null hypothesis which
states that ‘Malaria has no correlation with typhoid’.
The rate of co-infection between Salmonella species and
malaria is shown in table 2. Of the 136 malaria positive
samples , S. typhi were 15 (11%);S. paratyphi A 81
(60%);S. paratyphi B were 34 (25%); and S. paratyphi C
were 06 (04%)( Table 2).
Out of 136 malaria positive patients, salmonella was
isolated from the stool of 22(16%) patient samples. The
33
Research
Article
Kamga et al.: Buruli Ulcer In Cameroon: An Assessment Of The Community Knowledge
Pattern. AJIH 2013, 02:36-39
widal test indicated 91(67%) positive patient samples with
persistence fever for more than 24 hours after appropriate
antibody titre≥ 1/160 for o antigen (Table 3).Out of 52
antimalarial treatment, should be investigated for or
control samples, 16 indicated positive for salmonella sp.
empirically treated for enteric fever [ 10 ]. The incidence
using the widal test (antibody titre≥1/160 for O antigen).No
of typhoid and malaria co-infection will greatly reduce if
salmonella sp. was isolated from any of the control stool
the diagnosis of typhoid fever in malaria endemic areas
samples using the culture technique (table 3)
such as Buea is based on stool culture from our result
findings or blood culture based on previous report.
Discussion
A total of 67% rate of co-infection of malaria parasites and
Authors ‘contributions: The authors contributed equally
salmonella species was observed using the WIDAL test
to data collection analyses and manuscript revision.
while 16% rate of co-infection was observed using culture.
This prevalence is slightly similar to 47%,17% forWidal
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Bolak and Tebid: Malaria parasites and salmonella species co-infection rate among patients attending the Buea
regional hospital, AJIH 2013, 02: 32-35
Research
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