Prevalence and Risk Factors Associated with Intestinal Parasitic Infection among Primary School Children in Dera District, Northwest Ethiopia

Background Globally, over 600 million school children are living with intestinal parasites. The prevalence of intestinal parasitic infections (IPIs) among school children in Ethiopia and the Amhara region is 52% and 51%, respectively. The present study aimed to determine the prevalence and associated risk factors of IPIs among primary school children in Dera district, Northwest Ethiopia. Methods A school-based cross-sectional study was conducted from December 2019 to February 2020. The study used a structured pretested questionnaire and stool tests to obtain epidemiological and disease data. Data were analyzed using appropriate univariate and multivariable logistic regression methods by statistical package for social science (SPSS) version 25.0. Results Of the 382 students who were examined for IPIs, 238 (62.3%) (61.8% males, 62.8% females) were positive for one or more IPIs. One hundred thirty-six (35.6%), 98 (25.7%), and 4 (1.05%) were single, double, and triple infections, respectively. Out of the nine species of IPIs detected, Entamoeba sp. was the predominant species (29.6%) followed by hookworm (21.7%), Schistosoma mansoni (11.3%), Taenia sp. (9.2%), Giardia lamblia (5.2%), and Ascaris lumbricoides, Hymenolepis nana, and Enterobius vermicularis (4.2%) each, and Trichuris trichiura (0.5%). Family size greater than five (AOR = 1.8; 95% CI: 1.004, 3.13), open field school waste disposal (AOR = 15.88; 95% CI: 1.91, 132.1), and lack of knowledge about intestinal parasitic infection (AOR = 1.8; 95% CI: 1.1, 3.2) were the independent risk factors associated with the overall prevalence of IPIs. Conclusions The prevalence of intestinal parasitic infection was high in the Dera district. Health education, extending school-based deworming, and mass treatments are recommended.


Introduction
Intestinal parasites are found in the gastrointestinal tracts of humans and other animals [1]. Globally, about 3.5 billion people are affected by parasitic infections. e annual morbidities and mortalities due to IPIs are estimated to be over 450 million and 200,000, respectively [2]. Morbidity and indirect effects of IPIs have a substantial impact on health and quality of life [3]. e World Health Organization (WHO) estimated that over 270 million preschool children and over 600 million school children are living in areas where the parasites are widely transmitted [3].
In Ethiopia, 81 million people live in areas vulnerable to intestinal parasites, among which 25.3 million are school children (SC) [6]. Similarly, Ethiopia is a country with the lowest quality of drinking water supply (34%) and latrine coverage (7.1%) in the world [7]. Of the 7.1% latrine coverage, the latrine utilization level in Ethiopia is 50.02% [8].

Study Area.
is study was carried out in five primary schools from Dera district, South Gondar Zone, Amhara region, Northwest Ethiopia ( Figure 1). It is located 535 km northwest of Addis Ababa (the capital city of Ethiopia) and 42 km away from Bahir Dar. Its geographical location is 11°4 3′ 0″ N and 37°38′ 0″ E and its elevation ranges from 1,560 to 2,600 m above sea level. Its mean annual temperature and rainfall are 26°C and 1250 mm, respectively. Agroecologically, 85% of the district is lowland and the remaining 15% highland. Based on the 2007 projected national housing and population census, the total population of the district was 248,464 (126,961 males, 121,503 females). e majority of the population (93.25%) lived in rural and 6.75% in urban areas. e main economic activity of the people in this area was agriculture [20].
ere are 11 health centers and 36 health posts in the district. Health posts are assigned to implement the health extension program. Health Extension Workers (HEWs) spend 50% of their time visiting families in their homes and performing outreach activities in the community. HEWs are well-trained to provide first aid; treat diseases like malaria, dysentery, IPIs, and other ailments; and refer complicated cases to the nearest health center [21]. e district is rich with surface and groundwater resources such as Lake Tana and Abay River. However, access to clean water is limited.
us, the community depends on various unprotected water sources.

Study Design.
A school-based cross-sectional study was conducted from December 2019 to February 2020 to determine the prevalence of IPIs and associated risk factors among primary school students of Dera district, Northwest Ethiopia.

Sample Size Determination.
e sample size was determined using the single population formula n � (Z 2 p(1 − p)/d 2 ) [22]. e estimation of the sample size was based on population and previous studies on the prevalence of IPIs in the study area, where n � sample size; Z � 1.96 at 95% confidence level; P � estimated prevalence rate 50% � 0.5, and d � margin of error 0.05. Since there was no similar study previously conducted in the area, a 50% prevalence rate of IPIs was taken assuming that IPIs are significantly prevalent among students in Gibtsawit, Mirafe Mariam, Wagira, Korata, and Enbosa Maseria primary schools. Accordingly, the total sample size was n � 1.96 2 0.50(1 − 0.50) 0.05 2 � 384 students.

Sampling Methods.
e five target schools were randomly selected from the 114 schools in the Dera district and the 384 students were selected using a simple random sampling method. e alphabetically arranged list of all students from the five schools (grades 1-8) served as a sampling frame. e respondents were grouped into three age categories 6 to 11 years (middle childhood), 12 to 18 years (early adolescence), and 19 to 21 years (late adolescence) [23].
2.6. Questionnaire Survey. Trained data collectors collected the information (sociodemographic characteristics, child behavioral characteristics, and past medical history) of every participant using interviews of structured questionnaires first developed in Amharic language and translated back to English while encoding the data. Data collectors also made clarifications of ambiguous questionnaires to children. e questionnaires were pretested and validated. e data collectors also checked the fingernail cleanness and the shoewearing habit of each student. e criteria for clean hands were properly trimmed fingernails, physically clean hands during observation, and handwashing habits after touching any dirt material and before eating. e data collectors considered the students knowledgeable about IPIs if they correctly mentioned at least two IPIs with their etiologic agents, modes of transmission, and prevention methods.

Stool Sample Collection.
Formed and semi-formed fresh stool samples were used for parasitological analysis. e children were trained on how to collect the stool samples hygienically and advised to bring their own 3 to 5 g fresh stools in labeled collection cups along with applicator sticks. Parents were engaged for children aged 6-11.

Stool Sample Examination.
Stool samples were examined under wet-mount and formol-ether concentration techniques. A portion of each of the stool samples was processed and examined microscopically using direct wetmount and formol-ether concentration techniques based on the procedures in WHO guidelines [24]. All developmental stages of the parasites (cyst, egg, larvae, and adult) were recorded.

Direct Microscopy (Wet Mount).
A direct wet-mount technique was processed by conventional iodine. About 2 g of each stool sample was emulsified with 3-4 ml normal saline (0.85% NaCl solution). en a drop of the emulsified sample was placed on a clean microscopic glass slide to observe the presence of trophozoites under the light microscope at 10X and 40X.
en, a few drops of iodine    [24]. One gram (1 g) of each stool sample was first emulsified with 3-4 ml of 10% formalin saline. An additional 3-4 ml of 10% formol saline was added and mixed thoroughly and passed through gauze. ree to four (3-4) ml of diethyl ether was added and mixed by inverting and intermittent shaking of test tubes for 1 minute and centrifuged at 3,000 rpm for 5 minutes. After centrifugation, the layers of fecal debris were detached from the side of the tube using an applicator stick. e fecal debris and the formol saline were discarded and the sediment remained at the bottom of the test tube. e sediment was then transferred to a slide and covered with a coverslip. e preparation was examined microscopically using the 10X and 40X objectives for the identification of cysts and eggs.
2.11. Data Analysis. Statistical package for social science (SPSS) version 25.0 (IBM SPSS Statistics) was used to analyze the collected data. Chi-square (χ 2 ) test was performed to verify the possible association between the prevalence of IPIs and sociodemographic characteristics, socioeconomic characteristics, behavioral factors, personal hygiene, and environmental sanitation factors. Logistic regression was used to measure the degrees of association between the prevalence of IPIs and their associated risk factors. In the modeling process, univariate analysis was first done with a 0.25 level of significance to select the candidate variables for multivariable analysis. e variables, with a P value of less than 0.25, were qualified and included in the multivariable analysis [25]. A P value below 0.05 was considered significant and 95% CI was used to show the accuracy of data analysis.

Ethical Considerations.
Before conducting the investigation, the investigator obtained ethical clearance from the Ethical Committee of Science College, Bahir Dar University (S1_File. Pdf ). Written consents were obtained from the parents/guardians of children after explaining the purpose and the procedures of the study. e laboratory test was conducted with strict privacy and confidentiality. Finally, albendazole, mebendazole, and praziquantel drugs were given to the students whose test results were positive by the nurses free of charge.

Data Quality Control.
e questionnaire was first pretested using thirty-five individuals outside the study population in other schools to avoid all ambiguities. All ambiguities were corrected before the questionnaires were administered to the actual study participants (S2_File. Pdf ). During questionnaire surveys, the principal investigator cross-checked every questionnaire to check whether it was correctly filled by data collectors or not. e effectiveness of the reagents (formalin, diethyl ether, normal saline, and iodine solution) was pretested before starting the diagnosis of the study subjects by the laboratory technicians. A parasitological Atlas was consulted to ensure the accurate identification of the parasite species [26].

Sociodemographic Characteristics of Study Participants in
Dera District 2019/2020. Table 1 depicts the sociodemographic characteristics of the study participants. Of the 384 randomly identified participants, two students (0.5%) were not voluntary to give stool samples and did not fill the structured questionnaire. Hence, 382 (99.5%) (50% male, 50% female) students participated in this study (response rate of 99.5%). e age of the participants ranged from 6 to 21 years. Two hundred fifty-four (66.5%) individuals fall in the age group 12 to 18 years, 123 (32.2%) in 6 to 11 years, and five (1.3%) in 19 to 21 years. ree hundred eight participants (80.63%) were from family sizes of more than five and 74 (19.37%) from less than or equal to five. e water sources of 67.8% of the students were from unprotected sources like springs, wells, and rivers. More than half (50.8%) of the students did not wear shoes.  (16,4.2% each), and T. trichiura (2, 0.5%). e prevalence of protozoan and helminths parasitic infections in the study area was 126 (33%) and 171 (44.76%), respectively.

Univariate and Multivariate Logistic Regression Analysis (LRA) of the Most Important Risk Factors for IPIs.
e most important risk factors for IPIs among primary school children in the Dera district were identified using univariate and multivariate logistic regression analyses (MLRA) ( Table 3).
Univariate logistic regression analyses showed that statistical differences in IPIs resulted due to variations in school, family size, modes of school waste disposal, knowledge of IPIs, playing with soil, suckling fingers, school toilet function, school water access, and household toilet (P < 0.25). e odds of IPIs were higher in Korata Primary School (COR � 3.13; 95% CI: 1.544, 6.344) than others, in students from schools openly disposing of wastes (COR � 2.167; 95% CI: 1.39, 3.375) than burying/burning, among students lack IPI knowledge (COR � 2.245; 95% CI: 1.371, 3.68) than those who knew, and among students who had school water access (COR � 2.112; 95 CI: 1.283, 3.5) than not.
In the multivariate regression, family size more than five, open school waste disposal, and lack of knowledge were more likely associated with IPIs (P < 0.05). Students from the family size above five (AOR � 1.8; 95% CI: 1.004, 3.13) were more likely to be infected by IPIs than those from five and below, students from schools where wastes were openly disposed of (AOR � 15.88; 95% CI: 1.91, 132.1) were prone to IPIs compared to those from schools which bury/burn wastes, and students who had no IPI knowledge were subjected to IPI (AOR � 1.8; 95% CI:1.1, 3.2) more than those known.

Risk Factors Associated with Entamoeba sp. Infection.
e multivariate regression analysis shows that drinking river water, eating soil, and lack of school water access were significantly associated with Entamoeba sp. infection (P < 0.05) ( Table 4). Students who used to drink river water (AOR � 2.35; 95% CI: 1.102, 5.866) were at high risk of Entamoeba sp. infection than those who used to drink handdug well water, students who ate soil (AOR � 3.96; 95% CI; 1.34, 11.67) were more prone to Entamoeba sp. than their counterparts, and students from schools which lack water access (AOR � 1.773; 95% CI: 1.004, 3.13) were more likely infected by Entamoeba sp. than students from schools where there is enough water.

Risk Factors Associated with G. lamblia Infection.
Maternal handwashing habits and school toilet functions were the only predictors of G. lamblia in the multivariable analysis (P < 0.05) ( Table 4). Students from mothers who used to wash their hands with water alone, students from mothers who did not wash their hands, and students who did not use the school toilet were strongly associated with G. lamblia (P < 0.05). Students from mothers who used to wash their hands with water alone (AOR � 7.973; 95% CI: 0.97, 64.4) and students from mothers who did not wash their hands (AOR � 2.1; 95% CI: 0.17, 25.1) were subjected to  G. lamblia as compared to children from mothers who used to wash their hands with soap. Students who did not use the school toilet (AOR � 4.13, 95% CI: 1.3, 13.03) were prone to G. lamblia more than students who used to.

Risk Factors Associated with E. vermicularis Infection.
e household drinking water source was the only risk factor associated with E. vermicularis (P < 0.05) in the multivariable analysis (Table 4). Students who used to drink locally  10.095) were more likely to be infected with E. vermicularis than students who used to drink chlorinated water.

Risk Factors Associated with Taenia sp. Infection.
Statistically significant differences in Taenia sp. (P < 0.05) were seen with differences in grade levels and school toilet functions in the multivariate logistic regression analysis (Table 4). Grades 1-4 and not using the school toilet were associated with Taenia sp. infection. Students from grades 1-4 (AOR � 2.28; 95% CI: 1.08, 4.814) were more likely to be infected by Taenia sp. than students from grades 5-8 and students who did not use school toilet (AOR � 2.651; 95% CI: 1.176, 5.973) were more subjected to Taenia sp. than children who did use the school toilet.

Risk Factors Associated with A. lumbricoides Infection.
Only the habit of eating raw meat resulted in statistically significant differences in A. lumbricoides infection (P < 0.05) (
However, it disagrees with the studies done in Gobgob Northwest, Ethiopia, where males (38.9%) were more infected than females (26.4%) P < 0.05 [39]. is equal chance of IPIs among males and females may be due to the narrowing of gender role differences in the study area.
e study area is known for irrigation activities and children participate in agricultural activities to help their parents. e district has rivers (Gumara and Gelda), Lake Tana, Wagira Dam, and other smallest springs used as water sources. e prevalence of Taenia sp. (9.2%) was in line with the studies done in Nigeria (5.3%) [43], Malaysia (9.5%) [50], and Gobgob, Northwest Ethiopia (7%) [39]. However, it was higher than that of Delo-Mena district, Ethiopia (0.2%) [35], Gurage Zone, Ethiopia (1.6%) [37], Homesha District, Northwest Ethiopia (1.77%) [33], and Jawi town, Ethiopia (3%) [19]. Consumption of raw meat and vegetables, drinking water from unprotected water sources, playing with soil, grade level, presence of domestic animals, the habit of sucking fingers, the habit of open defecation, and participating in agriculture activities might be reasons for Taenia sp. infection.
e present study showed that family size was strongly associated with IPIs. e likelihood of being infected by IPIs among students belonging to a family size of above five was twofold compared to students belonging to a family size of less than or equal to five. e present finding agrees with other studies conducted in Ethiopia [29,37,38]. Increasing the family size may increase overcrowding that in turn may lead to contamination with each other. Besides, families with large sizes may face economic problems so that their members may face undernutrition, poor sanitation, poor medication, and poor personal hygiene.
Students who lack knowledge of IPIs were twofold more likely to be infected than students who knew IPIs. is finding agrees with the studies done in Malaysia [50,61]. e possible reason might be that students who did not know may have practiced activities that expose them to IPIs. Similarly, students may not protect their personal and environmental hygiene, could play with the soil, and practice open field defecation.
Open field school waste disposal activities in the study area were strongly associated with the prevalence of IPIs. Students from schools that practiced open field waste disposal activities were sixteen times prone to IPIs compared to students from schools that did not openly dispose of wastes. e outcome agrees with the study from Ethiopia [33]. Open field waste disposal activity might be a source of infection since students may touch wastes while playing on the ground. In the study area, 28.8% of the schools practiced open field waste disposal activities. e odds of having Entamoeba sp. infection among school children who used to drink river water were twofold higher than that of their counterparts. is was in line with the studies reported by Hailegebriel and Nasiri et al. [29,52]. River waters might be contaminated by flooding and wastes from domestic animals. Likewise, students who ate soil were fourfold more likely to be infected by Entamoeba sp. than their counterparts.
is might be because the soil could contain amoeba cysts. However, geophagia was not previously reported as a risk factor for Entamoeba sp. infection.
Mothers' handwashing by water alone and not using school toilets by students were risk factors associated with G. lamblia infection. e odds of having G. lamblia infection among students whose mothers did wash their hands with water alone were eightfold higher than students whose mothers used to wash their hands with soap and water. On the other hand, students from mothers who did not wash their hands at all were twofold more likely to be infected with G. lamblia than their counterparts. is might be due to the fact unwashed hands could have a cyst of G. lamblia. Washing hands only by water may not clean the microcyst of G. lamblia from their hands.
Students who did not use the school toilet were four times more likely to be infected by G. lamblia than students who used the school toilet. Open defecation in the school compound might result in infection by G. lamblia while students play in the school compound, or perform outreach activities.
Students who used to drink unprotected water were 1.378 times more likely to be infected by E. vermicularis than students who used to drink chlorinated and boiled water (protected water). Drinking water sources might be infected due to open field defecation, human and animal contact, and wind. e outcome disagreed with the studies reported in ailand, China, and Marshall Islands [59,62,63]. Grade and the school toilet function were risk factors for Taenia sp. (Table 4). e odds of having Taenia sp. in grades 1-4 was twofold more likely to be infected than that of students in grades 5-8. Being free to play on the ground, eating unwashed vegetables and fruits, eating raw meat, drinking raw milk, and poor personal hygiene among children who were in grades 1-4 may be the possible reasons for their infection.
Not using the school toilet was associated with a Taenia sp. infection. Taenia sp. infection increased threefold in students who did not use school toilets compared to students who used school toilets. Children who used open defecation in their school compounds may have disseminated Taenia sp. infection to their healthy friends. All schools in the study area did not have handwashing facilities after toilet use. e ova and proglottids of Taenia sp. might pass from student to student during playing.
Eating raw meat was the major associated risk factor for A. lumbricoides infection in the study area. Children who ate raw meat were fifteen times more likely to be infected by A. lumbricoides than children who did not eat raw meat. e study outcome disagrees with the findings from the Gurage zone, Southcentral Ethiopia [37]. Personal hygiene of slaughters and contaminated butchering areas might be the reason for the difference. In Ethiopia, especially in the countryside, there are no specified abattoirs. People perform slaughters on open grounds so that the chance of contamination with soil and soil-transmitted infections may be high.

Limitations.
e study was limited to only wet-mount and formol-ether concentration techniques. Not using Kato-Katz, PCR, and Ziehl-Neelsen techniques may underestimate the prevalence of IPIs in the area.

Conclusions
e prevalence of IPIs is high in the study locality. No clear difference in the prevalence of IPIs exists across the five schools. Family size greater than five, open field school waste disposal activities, and lack of knowledge of IPIs among children are independently associated with the overall prevalence of IPIs. We recommend community-based health education, mass treatment, and school-based deworming without interruption.
Data Availability e data supporting the conclusions of this article are within the article and the supplementary file.

Conflicts of Interest
e authors declare that they have no conflicts of interest.