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Tanzania Journal of Health Research, Vol. 12, No. 3, 2010 Prevalence of intestinal parasitic infections among patients
attending Bugando Medical Centre in Mwanza, north-western Tanzania: a retrospective
study H.D. MAZIGO1*,
E.E. AMBROSE1, M. ZINGA1, E. BAHEMANA1, L.L.
MNYONE2, E.J. KWEKA3, and J. HEUKELBACH4 1Department of Medical Parasitology
and Entomology, Weill-Bugando University College of Health Sciences, P.O. Box
1464, Mwanza, Tanzania Code Number: th10023 Abstract: Gastrointestinal
helminths and protozoan parasites may cause mild, acute and chronic human
infections. There is inadequate reliable information on the epidemiology of
these parasites among patients attending tertiary hospitals in Tanzania. This retrospective
study was conducted using hospital data obtained from the Department of Medical
Parasitology of Bugando Medical Centre (BMC) in Mwanza, Tanzania. A total of
3152 stool samples were recorded from January 2008-March 2010. Intestinal
parasitic infections were recovered in 57.1% (1799/3152) of the stool samples. Helminths
eggs were observed in 36.6% (1,153/3,152) of the samples with hookworm eggs
recovered in 25.2% (793/3125) and S.
mansoni in 5.6% (177/3125) of the samples. Protozoan parasites were
recovered in 20.5% (646/3152) of the samples in which 13.6% 428/3152) had Entamoeba histolytica/ E. dispar and 6.9%
(218/3152) Giardia lamblia. Prevalence
of intestinal helminth infections was higher in females, 55.7% (95CI%,
51.7-59.7, n= 642) than males (n=511, 44.3%, 95%CI, 40.3-48.6). Similarly, the
prevalence of protozoan infections was significantly higher among females
(58.1%, 95%CI, 53.1-63.1) than males (42.3%, 95%CI, 36.5-48.2). The prevalence
of helminth infections was highest among 45+ years olds and lowest in the 0-4
years olds while that of protozoan infections was highest in the 5-14 years age
group (30.9%, 95%CI, 27.9-33.8) and lowest in the 0-4 years age group. In
conclusion, this study shows that intestinal helminth and protozoan infections
are among the common parasitic infections among patients presenting at BMC.
This information may provide invaluable statistics needed for planning
meaningful public control programmes that aim at reducing the prevalence and
morbidity of parasitic infections. Keywords: helminth,
protozoa, parasitic infections, prevalence, hospital, Tanzania Introduction Intestinal
helminths and protozoan parasites are major public health problems in developing
countries (Lwambo et al., 1999; Handzel
at al., 2003; Bethony et al., 2002). These infections have
common characteristics - they are highly endemic in populations with low
socio-economic status and poor hygiene, favouring larval skin penetration and
oral-faecal transmission (Ravdin, 1995; Hotez et al., 2004; Sayyari et al.,
2005, Bethony et al., 2006). The
parasites are important causal agents of gastrointestinal disorders such as diarrhoea,
dysentery, vomiting, lack of appetite, haematuria, abdominal distension and
sometimes mentally related disorders (Garcia, 2004; Bethony et al., 2006). Moreover, heavy chronic
infections with Ascaris lumbricoides
and hookworms (Ancylostoma doudenale
or Necator americanus) may cause
malnutrition and anaemia in high risk groups (Albanico et al., 1998; Awasti et al.,
2003; Hotez et al., 2004). Chronic
infections with Schistosoma species (S. haematobium and S. mansoni in Tanzania) have been associated with hepatomegaly,
splenomegaly, periportal fibrosis, hypertension, urinary bladder obstructions,
cancer and tumour of the prostate glands (Boros, 1989; Guyatt et al., 1999; Haidar, 2001; Malenganisho
et al., 2008; Mazigo et al., 2010a). In northwest Tanzania, there is inadequate information on the magnitude
of parasitic infection among cases attended at tertiary hospitals. It has been
described that information generated from in-patients departments of hospitals
may provide the initial information needed for planning meaningful public
control programmes (Obiamiwe, 1972). In addition, differentiation of parasitic
agents is an important step for initiation of tailored treatment and prevention
strategies. Therefore, the present retrospective study was conducted to
determine the species and prevalence of human intestinal parasites among
in-patients at Bugando Medical Centre in Mwanza, Tanzania. Materials and Methods Study
area The study was conducted at Bugando Medical Centre in
Mwanza, north-western Tanzania. This referral hospital is situated along the
southern shores of Lake Victoria and has a 900 bed-capacity. BMC is located between
latitudes 2o15-2o45S and longitudes 32045- 450
38 E and lies at an altitude of 1140m. The hospital serves as a referral
centre for tertiary specialist care for a catchment population of approximately
13 million people from Mwanza, Mara, Kagera, Shinyanga, Tabora and Kigoma
regions of Tanzania (http://www.bugandomedicalcentre.go.tz). Data collection and
analysis The study examined sample records of laboratory
results contained in a designed computer database. The data covered the period
of 27 months from January 2008 to March 2010. The routine stool examination
method was a direct smear and 10% formol-ether concentration technique (WHO,
1991). All stool sample records were examined and positive results for
helminths eggs, larvae and protozoan cyst or trophozoite infections were
recorded. Variations in distribution
patterns of positive stool samples between sex and age were determined. The prevalence
of infections was reported in proportions. Chi-square test (χ2)
was used to compare relative frequencies between groups (sex and age). Data
analysis was conducted using SPSS version 11.5 (SPSS Inc, Chicago, Illinois). Ethical considerations Ethical clearance to conduct this study was obtained
from the Bugando Medical Centre Ethical Committee (Ref: AB.286/317/01/41). Results A
total of 3152 stool samples (1887 in 2008, 963 in 2009 and 302 in 2010) were
submitted to the Department of Medical Parasitology of BMC and included in the analysis.
Of these, 1153 (36.6%; 95%CI, 33.9-39.4) were positive for intestinal helminths
and 646 (20.5%, 95%CI, 17.4-23.6) for intestinal protozoa. Hookworm accounted
for the most prevalent parasitic infection (25.2% (95%CI, 22.2-28.2; n=793) followed
by Schistosoma mansoni, 5.6% (95%CI,
2.2-9; n=177) (Table 1). Entamoeba
histolytica/ E. dispar (13.6%, 95%CI, 6.6-20.8) and Giardia lamblia (6.9%, 95%CI,-0.001-14.3) were the only intestinal
protozoan observed in the study (Table 1). Table 1: Prevalence (%) of helminth and protozoan
infections, March 2008-Jan 2010
Prevalence
of intestinal helminth infections was higher in females, 55.7% (95CI%, 51.7-59.7,
n= 642) than males (n=511, 44.32%, 95%CI, 40.3-48.6) (P<0.002) (Table 2). The prevalence of protozoan infections was
20.5% (95%CI, 17.5-23.6, n=646) and it was significantly higher among females
(58.1%, 95%CI, 53.1-63.1) than males (42.3%, 95%CI, 36.5-48.2) (Table 2) (P<0.005). Table 2: Prevalence (%) of helminth and protozoan
infections stratified by sex
Age
group specific prevalence of helminthes was highest among 45+ years olds and
lowest in the 0-4 years olds (Table 3). Age-specific prevalence for protozoan
infections were highest in the 5-14 years age group (30.9%, 95%CI, 27.9-33.8)
and lowest in the 0-4 years age group (Table 3). Table 3: Prevalence (in %) of helminth and protozoan infections
stratified by age
Discussion In
general, the prevalence of intestinal helminthes and protozoan parasites
detected in the present study was similar to a previous study in Nigeria
(Ozumba & Ozumba, 2002). The prevalence of intestinal helminth observed in
this study, confirm that intestinal helminthiases, mainly hookworm infection, are
prevalent among patients attending Bugando Medical Centre, and mostly likely in
its catchment area. Previous epidemiological surveys within the Lake Victoria
basin have also reported a high prevalence of hookworm infections than other
geohelminths (Lwambo et al., 1999;
Mazigo et al., 2010b). The higher
prevalence of hookworm infections has previously been reported in other rural
tropical areas of low socio-economic status (Hotez, 2003; Standley et al., 2010). Similarly, the high
prevalence observed in our study likely to be associated with poor hygienic
conditions and low socio-economic status of the population in the Lake Victoria
basin. On the other hand, the prevalence of other helminths, A. lumbricoides, E. vermicularis and Trichuris
trichiura were very low. Indeed, earlier studies in the nearby Magu district, reported a prevalence
of <1% of A. lumbricoides, Trichuris
trichiura and E. vermicularis
(Lwambo et al., 1999) while one of our previous studies in the nearby Sengerema district did
not detect any A. lumbricoides, T. trichiura
or E. vermicularis (Mazigo et al., 2010b).
The low prevalence of these parasites is likely to be influenced by the ecological
factors within the Lake Victoria basin. Contrary to findings from field
epidemiological studies, this study observed a low prevalence of S. mansoni (5.6%). Prevalence between
64% and 68% have recently been reported (Standley et al., 2010; Mazigo et al.
2010b). The prevalence of E. histolytica/
E. dispar and G. lamblia reported
in the present study was similar to that reported from Cameroon (Mbuh et al., 2010). The high prevalence of E. histolytica/ E. dispar could be due
to the existence of resistant cysts of the parasite in the study area as
reported by Mbuh et al. (2010) in a
recent study Cameroon. When the prevalence of intestinal helminthiasis was analysed by sex, the
females had a higher frequency of hookworm infections whereas the males had
higher frequency of infections by S.
mansoni, E. vermicularis and T.
trichiura. Such sex predominance in infections rates is likely to be a
reflection of different behaviour between the two groups (Albanico et al., 1997; Hotez et al., 2006). In a recent study in Cameroon, it was found that the
higher prevalence of human intestinal protozoans in females was attributed to
the fact that women usually eat unwashed fruits and vegetables or unboiled
salads which may be contaminated with protozoan cysts (Mbuh et al., 2010). The trend of increasing prevalence of helminths with age observed in
this study has been previously reported by other workers in the region (Lwambo et al., 1999; Mazigo et al., 2010b). However, it was different
from the normal U-shaped curve reported from a study by Kurup et al. (2010). Our findings suggest that
every individual in the region is at high risk of helminth infection. The age
relationship in the prevalence of E. histolytica/
E. dispar and G. lamblia has been
reported in various regions of Cameroon (Rossignol et al., 2001; Mbuh et al.,
2010). In conclusion, this study shows that intestinal helminthiases and
protozoan infections are among the common parasitic infections observed among patients
presenting at BMC. This, and similar information, generated from hospitals may
provide invaluable statistics needed for planning meaningful public control
programmes that aim at reducing the prevalence and morbidity of parasitic
infections. Acknowledgements The
authors acknowledge the support of laboratory technicians at the Department of
Medical Parasitology, BMC during data collections and cleaning. References
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