Prevalence of intestinal helminths and associated factors among school children of Medebay Zana wereda; North Western Tigray, Ethiopia 2017
Teshale et al. BMC Res Notes
Prevalence of intestinal helminths and associated factors among school children of Medebay Zana wereda; North Western Tigray, Ethiopia 2017
Tsega Teshale 0
Shewaye Belay 1
Desalegn Tadesse 1
Abraham Awala 1
Girmay Teklay 2
0 Department of Laboratory, Aksum University , Po Box: 298, Aksum, Tigray , Ethiopia
1 Department of Parasitology and Entomology, Mekelle University , Mekelle, Tigray , Ethiopia
2 Department of Pediatrics and Child Health Nursing, School of Nursing, Aksum University , Aksum, Tigray , Ethiopia
Objective: To assess the prevalence of intestinal helminth infections and associated factors among primary school children of Medebay Zana wereda, a northwestern zone of Tigray, northern Ethiopia from March to April 2017. Result: The prevalence of intestinal helminths was 12.7%. The highest prevalence of intestinal helminth infections was observed in the age group of 11-14 years old and the most prevalent helminths species were Schistosoma mansoni. Mothers' level of education [AOR = 0.27 [0.13-0.58]], place of defecation [AOR = 2.63, 95% CI 1.14-6.02]], hand wash before meals [AOR = 9.0, 95% CI 3.72-21.74]], hand wash after defecation [AOR = 5.77 [1.78-18.63]] and eating unwashed vegetables [AOR = 5.67 [2.19-14.73]] were associated with higher risk of having intestinal helminths detected in stool. In the study area the risk of detecting intestinal helminths in their stool were more associated the improper personal hygiene of the children.
Helminths; STH; Schistosoma; Schistosomiasis; Mother's education; Open defecation
About 610 million school age children of the world are
at risk of infection with a common intestinal helminths
] like hookworm, A. lumbricoides, T. trichiura,
Strongyloides stercoralis, Hymenolepis nana and Schistosoma
]. Those infections are resulted from
socioeconomic factors, cultural practices and poor sanitation
which are transmitted by ingestion of soil contaminated
egg, poor hand hygiene, eating unwashed fruit, under
cooked infected meat and poorly washed vegetable
. Skin penetration while walking bare foot on larvae
infected soil and skin penetration by swimming in
cercariae bearing water are anther transmission mechanism
of helminths [
Infestation by intestinal helminths is the major
public health problem which causes chronic inflammatory
disorder such as chronic anemia, growth stunting,
protein-calorie malnutrition, fatigue, poor cognitive
performance, reduce long term survival, diminished physical
fitness and school attendance in school-age children [
]. Intestinal helminths infections like acute and chronic
complications of S. mansoni also cause very severe
consequences like abdominal pain, diarrhea,
hepatosplenomegaly, portal hypertension, and upper gastrointestinal
Worldwide, about 100 million of intestinal worm
harboring school-children experience stunting or wasting
]. Severity in intestinal helminths resulted from
fluctuation in metabolic rate, anorexia, chronic anemia,
obstructing intestinal lumen of children associated with
heavy worm-load .
In Ethiopia, intestinal helminths are resulted from poor
environmental sanitation, unsafe human waste disposal
systems, lack of safe water supply and low
socio-economic status of the country [
]. The main reason for
their persistent presence everywhere is due to frequently
low rank in the list of priorities in public health
programs because the effect of helminthic infections are not
directly measured explicitly in terms of mortality figures
Though studies on intestinal helminths and associated
factors have been conducted in different parts of
], the prevalence of intestinal infection
in the local area has not yet properly documented. This
study will help for school community to improve their
environmental sanitation and to health office of Medebay
Zana wereda to design periodic mass-deworming
program. Therefore, the aim of this study was to assess the
prevalence of intestinal helminths and associated factors
among School Children of Medebay Zana wereda; Tigray,
Study design and setting
A school based cross-sectional study design was used to
collect data in eight primary schools of Medebay Zana
wereda from March to April 2017, located at 282 km
from Mekelle and about 1060 km far from Addis Ababa.
Its geographical location is between 38°20′E longitude
and 14°06′N latitudes [
]. About 9% of all houses in
urban had access to safe drinking water and 4% of rural
houses had toilet facilities [
Sample size calculation
The sample size was calculated using single population
proportion formula by taking the highest sample giving
from both prevalence and associated factors. We using
the previous prevalence from a study done in Enderta
] i.e. 41.46% with 5% margin of error and 95%
confidence interval. The final sample size with 10%
contingency was 410.
From the total primary schools in the wereda, eight
schools were selected randomly four from rural and four
from urban areas. From the eight selected schools with
1–8 grades, 410 children were taken by using simple
random sampling technique. Kato-katz technique were also
use for the laboratory investigation.
Source and study population
All students in elementary schools of Medebay Zana
wereda were considered as source population and all
randomly selected students grade 1–8 in eight selected
elementary schools were considered as our study subjects.
Data collection procedure and instruments
The data was collected using interviewer administered
structured questionnaire adapted from study done in
Lumam town, north west Ethiopia [
] and stool sample.
The adapted questionnaire was modified and
contextualized to fit the local situation and research objective. After
obtaining oral consent from teachers and parents and
assent from the students, each student was given a coded
stool collection container (clean plastic cup) and
applicator sticks and instructed to bring 6 g of his/her own fresh
stool. Two BSc in graduates’ in laboratory technology
were recruited as data collectors and one senior
professional nurse for screening of complications. Stool
collection was supervised throughout the time. On delivery of
the stool specimen the code of parasitological
investigation was filled properly on the prepared parasitological
format that was attached with questionnaire.
Following stool examination using Kato-Katz
technique, children who become positive for S. mansoni
infection were checked for palpable splenomegaly and
hepatomegaly. Those found with splenomegaly and
hepatomegaly were informed to their parents to take them
to hospital for further checkup and for free care of their
The dependent variable was detection of helminths in
stool samples and the independent variables were
sociodemographic factors like: age, sex, fathers and mothers
level of education, residence and other associated
factors like:- shoes wearing habit, place of defecation, water
source, hand washing habit before meal, hand washing
habit after defecation and habit of eating improperly
washed raw vegetables. Those variables was asked to the
caretaker of the children.
Data quality assurance
Training was given for data collectors. The
questionnaire was prepared originally in English and then
translated into the local language of study area (Tigrigna).
Questionnaires were pretested on 5% of the sample size
at Mekane-Eyesus primary school. All reagents were
checked for expired date. Close supervision was done by
the principal investigator.
Data processing and analysis
The Data was coded, entered, cleaned, edited and
analyzed using SPSS ver.22. The prevalence of intestinal
helminths was reported in percentages of detected
helminths in stool of the children. Binary logistic
regression was used to examine the association between the
dependent variable and each independent variable.
Variables which showed statistical significance during
bivariate analysis at p value ≤ 0. 20 were entered to multivariate
logistic regression to isolate an independent effect of the
predictors. Adjusted odds ratios (AOR) with 95% CI,
were estimated to assess the strength of associations and
statistical significance was declared at a p-value < 0.05.
Socio‑demographic characteristics of the study subjects
A total of 410 school age children were examined for
intestinal helminths with stool sampling success rate of
100%. Out of these respondents 58.5% were males and
238 (58%) were live in the rural area. About 238 (48.8%)
of the participants were belonged to households with
a family size range from 4 to 6. The mean age of study
participants was 11.41 ± 2.202 ranging 9–19 years old
Prevalence of intestinal helminths
In this study 12.7% (CI 9.60–16.30) of the participants
have at least one intestinal helminths detected in their
stool. The detected helminths in stool was high in the age
range of 11–14 years old with prevalence of 36 (13.5%).
In the study 405 (98.8%) of the children uses river water.
Among them 39 (9.6%) were had intestinal helminths
and 4 (9.8%) of them uses the river water for drinking,
washing and swimming. About 15 (18%) of the children
did not wear shoes and 32 (12.5%) were cross the flowing
river and irrigational area in their daily activity (Table 1).
Distribution of single and double infection
Five different helminthic species were recorded (A.
lumbricoides, Hookworm, S. mansoni, H. nana and T.
trichiura). Out of the detected helminths infection 33 (63.5%)
were occur in the age range of 11–14 years. From the
total intestinal helminths detected, 49 (94.2%) of the
children were having single infection of the helminths and 3
(5.8%) were co-infected with two different helminths A.
lumbricoides and T. trichiura (Table 2).
Splenomegaly and hepatomegaly with S. mansoni
In this study, the most predominant helminthic infection
was S. mansoni 20 (38.5%). From all children infected
with S. mansoni, 5% were with splenomegaly and 25%
had hepatomegaly and were linked to hospital for free
Risk factors for intestinal helminths infections
In the bivariate logistic regression at p-value of ≤ 0.2,
residence, mother’s educational status, place of defecation,
hand washing before meal, hands washing after
defecation, shoes wearing habit and eating unwashed vegetable
were statistically significant with having intestinal
helminths infections in the stool sample.
After entering these variables to multivariate
analysis by using backward elimination method, Mother’s
educational status, place of defecation, hand washing
before meal, hands washing after deification and eating
unwashed vegetable were statistically significant with the
detected intestinal helminthic infections in the stool at
p-value < 0.05 (Table 3).
The overall prevalence of intestinal helminths recorded
in this study was 12.7%. This was almost comparable
with the study done in Were-abay 12.22% [
] and Babile
town 13.8% [
]. But the result of this study was much
lower than the findings reported in Adwa town 69% [
Lumame town 54%) [
], Zegie Peninsula 69.1% [
in northern Gondar 66.7% [
]. This could be due to the
topographic and study period difference in which the
communities would improve their living standard,
personal and environmental hygiene through time.
Schistosoma mansoni was the most predominant
intestinal helminthes with prevalence of 20 (38.5%) and 4.9%
from the total participant. This is higher than the study
done in Were-Abaye with less than one percent [
might be due to the presence of irrigational areas and
flowing river that favor breeding of the intermediate host
(snail) in which the infected snails shed cercariae into the
water and penetrate the intact human skin. The second
intestinal helminth detected was Hookworm with
prevalence of 4.14% from the total participant and 17 (32.7%)
from the detected helminths in stool. This was higher
than a study done in Chencha town 2.2% [
] and lower
than studies conducted in Babile town 6.7% [
Jimma town 12.9% [
]. The prevalence of H. nana in this
study was 1.46% from the total participant and 6 (11.5%)
from the total helminths detected.
Out of the total helminths detected, 49 (94.2%) were
infected with single helminth infection. Lower than study
done in Chencha town 19% [
]. Unlike the studies done
in in Adwa town [
] with double infection of 18.4%, in
our study area only 3 (6%) of the school children were
infected with two different helminths (A. lumbricoides
and T. trichiura).
The parents of children at high level of education
provides better environment for their children. In contrast
to this idea, in our study the odds of intestinal helminths
in children with illiterate mothers were 72.8% less likely
to be infected than children with literate mothers at
p = 0.001. This may be due to the similarity of the
environmental condition between the schools and living
Human contaminative activities such as open field
defecation and use of unhygienic water supply for
bathing and drinking favor transmission of intestinal
helminths. In our study, students who excrete in open field
were about three (p = 0.023) times more likely to have
intestinal helminths in their stool than those who
defecate in latrine. This was different from the study done in
Lumame town [
]. This difference might be due to the
difference in topological and environmental sanitation
between the two study areas. Students who didn’t wash
their hands before meal were about nine (p = 0.000) times
more prone to develop intestinal helminths than those
who wash their hands before meal. The helminths might
be confined into the nail of the child and may cause
infections as they ingest food.
The odds of having intestinal helminths among children
who eat unwashed or undercooked vegetables in the stool
of the children were about six times higher (p = 0.000)
than those who eat washed or cooked vegetables. This
was similar with the study done in Lumame town [
This might be due to the unwashed or undercooked
vegetables and fruits may create a favorable media to eggs of
these helminths to infect children.
The overall prevalence of intestinal helminths recorded
in this study was 12.7%. Therefore, Health education
programs such as proper personal hygiene should be
strengthened in the school and community.
The study did not identify the actual cause of
hepatosplenomegaly in S. mansoni positive children. The absence of
broader health status of the community was another
limitation in which environmental assessment was not
conducted around the schools and communities. The study
also shares the limitation of the cross-sectional study
AOR: adjusted odd ratio; COR: crudes odd ratio; SPSS: Statistics Package for
Social Science; STH: soil transmitted helminths; BSc: Bachelor of Science.
TST: conceive of data and designed the study, supervised the data collection,
performed the analysis, interpretation of data, drafted the manuscript and
final approval of the revision for publication. SB: assisted in designing the
study, data interpretation and critically reviewed the manuscript. DT: assisted
in data interpretation and reviewed the manuscript critically. AA: assisted in
analysis, interpretation and reviewed the manuscript critically. GT: assisted in
revising the data for intellectual contents, methodology and interpretation
of the data with the statistics. Agreement to be accountable for all aspects
of the work in ensuring that questions related to the accuracy or integrity of
the work are appropriately investigated and resolved. All authors read and
approved the final manuscript.
Authors thanks to Mekelle University and the data collectors, supervisors and
The authors declare that they have no competing interests.
Availability of data and materials
All data is available via this manuscript.
Consent for publication
Ethics approval and consent to participate
The study was approved by the institutional research review board of Mekelle
University College of health science. An official permission was also secured
to Tigray regional health bureau. Then a permission and support letter was
written to the education and health office Medebay Zana. Oral consent from
school directors and parents and assent from the children was obtained after
explaining the purpose of the study. Information was recorded anonymously
and confidentiality were assured throughout the study period.
No funding was received.
Springer Nature remains neutral with regard to jurisdictional claims in
published maps and institutional affiliations.
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