Prevalence of Intestinal Protozoa and Soil Transmitted Helminths Infections among School Children in Jaragedo Town, South Gondar Zone of Ethiopia

Background Parasitism is a relationship where one, the parasite, harms the host or lives at the expense of the host. Intestinal parasites (protozoa and STHs-soil-transmitted helminths) cause gastrointestinal tract infection in humans and animals. Intestinal parasitic infections (IPIs) predominate the tropics and subtropics and affect poor countries, where school children suffer the most. To prevent and control these infections, local risk factors must first be identified. The aim of the study was to determine the prevalence of intestinal parasitic infections and associated risk factors among school children in Jaragedo town schools, South Gondar Zone of Ethiopia. Methods A cross-sectional study was conducted from October 2018 to April 30, 2019, involving 396 students from one elementary and one secondary school. Stratified simple random sampling method was used. A questionnaire was prepared to collect sociodemographic and socioeconomic data of the study subjects. Stool samples were collected and examined using formalin-ether concentration technique. Data were analyzed using SAS software version 9.4. Descriptive statistics were used to give a clear picture of population characteristics. Logistic regression was also used to determine the relationship between dependent variables (primary infection) with independent (explanatory) variables using SAS software. Results Results showed that the overall prevalence of intestinal parasitic infections was 65.4%. E. histolytica was the most prevalent intestinal parasite (12–14%) followed by G. lamblia (8–9%); other parasites could not infect more than 5% of the study subjects. Generally, parasitism did not vary between the sexes. The logistic regression analysis showed that grade, level of students, water source, habit of consuming raw meat, and level of income had a strong effect on intestinal parasitic infection (P < 0.05). Other explanatory variables were not significant (P > 0.05). High prevalence of parasites indicates improper disposal of waste, low socioeconomic level, low living standard, and poor water quality. Conclusion Therefore, short-term and long-term intervention strategies are required to minimize rates of infection.


Introduction
Parasitism is the relationship in which one of the participants, the parasite, harms or lives at the expense of the host. Parasites may cause mechanical injury, dig into the skin or other tissues of its host, stimulate an inflammatory or immune responses, or simply rob the host of nutrition. Most parasites inflict a combination of those conditions on their hosts [1].
Intestinal parasites infect the gastrointestinal tract and affect health [2]. Parasitic protozoa are single cell microorganisms that possess one and rarely two nuclei. e two most prevalent intestinal protozoa among children are E. histolytica and G. lamblia. E. histolytica/dispar infects 10% of the worlds' population, while the prevalence may rise as high as 50% in many countries [3]. e prevalence of giardiasis was 2 to 7% in developed and 20 to 30% in developing countries. e disparity in prevalence emanates from factors such as geographical area, the urban or rural setting of the society, age, and socioeconomic conditions [4]. Parasitic helminths include nematodes (round worms), trematodes (flukes), and cestodes (tapeworms). e transmission is by contact with water, food, or soil contaminated with infected human feces; these infections cause anemia, vitamin A deficiency, stunted growth, malnutrition, intestinal obstruction, and impaired mental development. e global prevalence of soil-transmitted helminths is high. Recent estimates show that 1472 million people have round worms, 1298 million have hookworms, and 1049 million have whipworm infection [5]. Soil transmitted helminths and protozoan intestinal infections are common among preschool and school-age children. Children tend to play on soil, suck fingers, and defecate in open fields. Maternal awareness also has its own impact on the prevalence. In Ethiopia, poor sanitation and poor personal hygiene and lack of potable water contribute to the high prevalence of parasitism and the associated morbidity and mortality [6]. Playing with soil, sucking fingers, defecation in open fields, lack of potable water, lack of latrines, contact with animals, poor waste disposal system, walking barefoot, poverty, and occupation of family members all contribute to the high parasitism level. Soil transmitted helminths and protozoan intestinal infections are common diseases in Ethiopia. In Jaragedo town, South Gondar zone, Ethiopia, diarrheal cases are common, but the status of school children with respect to helminths and protozoan intestinal infections is unknown, and the current study was conducted to address the gap.

Description of Study Area.
e study was conducted in Andabet district, Jaragedo town, South Gondar zone, Amhara region, Ethiopia. Andabet district covers an area of about 8000 ha, and it is located 150 km from Bahir Dar, the regional capital, and 91 km from Debre Tabor, the zonal capital. e total population is 154,797 (51.2% male and 48.8% female). e area receives an annual rainfall of 673.2-1538 mm, temperatures range from 11-25.5°C, and altitudes vary between 1500 and 2300 m above sea level. e geographical location of Andabet district is 11°10′ to 11°30′ North latitude and 37°45′ to 38°00′ East longitude. In Andabet district, 19 rural and 2 urban kebele administrations are found, one of which is Jaragedo kebele. Jaragedo town has a population of 8894 (5257 males and 3637 females), and it is located 12 km from Andabet town. One-half (50%) of the residents are farmers, 15% merchants, 3% weavers, and 2% others. And 95% of the town dwellers are Orthodox Christian, and 5% are Muslims (Jaragedo community administration, Pers. Comm., 2010). About 66% of the population had access to pipe water.

Study Design.
A cross-sectional study was conducted from October 2018 to April 30, 2019, to determine the prevalence of soil-transmitted helminths and protozoan intestinal infections and associated risk factors among school children of Jaragedo primary school and Jaragedo secondary school.

Sample Size Determination and Sampling Technique
2.3.1. Sample Size Determination Technique. A total of 403 (202 females and 201 males) were included in the study. Out of these, 102 male and 101 female students were from the Jaragedo primary school and 100 male and 100 females from Jaragedo secondary school. Fifty-percent prevalence rate was used in the sample size calculation because there was no published report in the study area. e minimum sample size "n" required was determined using the statistical formula [7].
where n � required sample size, Z � standard value of 1.96, p � prevalence rate, and m � margin of error of 0.05. To minimize errors arising from nonresponse, 5% of the sample was added to the initial estimate. Seven students were excluded from the study because of insufficient data; the total sample size was, therefore, 396 students.

Sampling
Technique. Students were stratified according to grade level (1-4, grades 5-8, and 9-10) to select target groups. Quota was allocated for each stratum, grade level, and section. Finally, a systematic random sampling technique was used by using the classroom roster as a sample frame.

Inclusion and Exclusion
Criteria. All children registered in both schools and who agreed and signed the consent were included in the study. Students who were treated for intestinal parasites in the last two months and those whose parents were unwilling were excluded.

Data Collection.
A structured questionnaire was prepared to collect sociodemographic and socioeconomic data of the study subjects (including risk factors). e questionnaire was first written in English and then translated into Amharic. Students and parents filled the questionnaire. Fingernails of children were inspected. Accuracy and completeness of the filled questionnaire were verified at the end of each day. Immediately after that, each child was given a dry, clean, and leak proof stool cup labeled with the identification number and an applicator stick. Students were advised to fill the stool cup with their own fresh stool about the size of a bean (approximately 3 g) and bring them to the researcher. Stool samples were preserved in 8 ml of 10% formalin solution and transported to Jaragedo Health Center for parasitological examination. A formalin-ether concentration technique was employed to examine the collected samples.

Formalin-Ether Concentration.
A formalin-ether concentration technique was adopted. About 1 to 1.5 g of stool specimen was mixed in a centrifuge tube containing 10 ml formalin mixture and stirred until a suspension formed. en, 3 ml of ether was added to the suspension and thoroughly mixed by putting a rubber stopper in the tube and then shaken for ten seconds. e tube was placed in a centrifuge for 2-3 minutes at 2000 revolutions per minute. en, the tube was removed from the centrifuge, where 4 layers have been observed from the top to the bottom (top layer ether, 2 nd layer fat debris, 3 rd layer formalin, and bottom layer sediment). e first three layers were discarded. A small amount of residual fluid was flown back to the sediment, properly mixed with the sediment, and a drop of suspension was transferred to a clean slide and covered with a cover slip. Finally, the slide was examined at 10x and 40x objectives for the presence of intestinal parasites.

Data Analysis.
Questionnaires and parasitological data were analyzed using SAS software version 9.4. Descriptive statistics were used to show population characteristics, i.e., age, sex, prevalence of intestinal protozoa, and soil-transmitted helminthic infections. Logistic regression was used to determine the relationship between dependent variables (primarily infections) with independent (explanatory) variables or risk factors by using SAS software. Parameter estimates were considered significant at α (alpha) � 0.05. Mother's level of education and hand washing habits of the study subjects before the meal were excluded from the logistic regression analysis because the sample size was not balanced; i.e., three study participants did not wash hands. Study subjects whose parents had college education were few, and this factor was excluded from the model.

Ethics Clearance.
e study was conducted after research ethics approval was obtained from Bahir Dar University, Science College, Bahir Dar, Ethiopia. Letters were written to schools, to district Health Office, and to Jaragedo Health Center. Participants were briefed about the objectives of the study and that all personal information was treated strictly confidential. Consent letter was prepared and ratified with students and parents. Study participants confirmed positive for intestinal parasites were treated free of charge.

Demographic Characteristics of Study Subjects.
Four hundred and six kids were selected for the study. Seven of them (∼2%) were excluded because of lack of stool samples. A total of 396 students took part in the investigation; 197 (49.7%) were male, and 199 (50.3%) were female. About 40% of the students were 17 years or older; 55% resided in rural and the rest in urban areas; 22% were in the first cycle of elementary school (1-4 grades), 28% were in the second cycle of elementary school (5-8 grades), and 50% students were from Jaragedo secondary school.

Socioeconomic Risk Factors.
Over 65% of the parents were illiterate, and most fathers were farmers. About half of the parents (∼48%) used both tap water and river water interchangeably; 38% of them used tap water alone. Over 70% of them belonged to the middle-income group; the rest were rich or poor. About 23% of the families involved had a family size less than 5, 60% had 5 to 6 members, and 20% above 7.

Behavioral Risk Factors.
Over 90% of the study subjects washed hands before meal and after toilet use; more than 75% of them washed vegetables. Slightly more than half of the kids did not consume raw meat. Most of the students (∼85%) wore shoes always. Over 90% of families had their own toilet in close proximity, and more than 80% of them buried household waste. On direct observation, about 35% of the students had unclean nails. e details are given in Table 1.

Prevalence of Intestinal Parasitic Infections.
Overall prevalence of intestinal parasitic infections was 65.4%. E. histolytica was the most prevalent intestinal parasite (12-14%) followed by G. lamblia (8-9%); other parasites, the ones that could not be grouped into any of the six species, infected less than 5% of the study subjects. Parasitism did not vary between the sexes (a difference of only about 2%) ( Figure 1).
As the odds ratios show, the prevalence of intestinal parasitic infections was high for students who were 15-16 years old, grades 9-10, rural dwellers, illiterate family heads, families who practiced farming, very poor families, river water users, and students with six family members ( Table 2). Kids who did not wash hands before the meal and who did not wear shoes were all found infected. e odds of being positive for intestinal parasitic infections were about twice higher among rural dwellers compared to urban dwellers. Students who did not wash their hands after use of the toilet had two times higher odds ratio having these infections compared to students who washed hands. Students from very poor families were 5 times more likely to be infected compared to kids from rich families; those who did not use latrines had two-fold chance of being affected compared to children who used latrines. Increasing level of education of fathers helped reduce infection compared to fathers without education. River water users were 7.5 times more likely to be infected compared to tap water users. e odds of being positive for intestinal parasitic infections were two times higher among kids in 15-16 age category compared to kids in 7-10 age categories. Secondary school grade levels were 2.5 times more likely to be infected compared to elementary school grade levels.
A large majority of the students were found infected by a single parasite (61%), and only 4% had double infection.
ose who consumed unwashed vegetables, whose nails were not clean, who disposed waste in open fields, and who had no latrine were found more likely to be infected.   of study subjects, habit of shoe wearing, water source, waste disposal system of families, latrine type, and accessibility had a strong effect on soil-transmitted helminthic infection (Table 6).

Hookworm Infection.
Hookworm infection was the third most prevalent species of parasites among school kids in Jaragedo town. e logistic regression showed significant association with wearing shoes, water source, and access to latrine (P < 0.05).

Other Intestinal Parasites.
During the parasitological examination, other intestinal parasites that could not be grouped to any of the six parasites were found in the stool samples in addition to the six species. eir overall prevalence was 9.1%. e logistic regression analysis showed that only water source had a strong effect on these other intestinal parasitic infections (P < 0.05).

All Intestinal Parasites.
e overall prevalence of intestinal parasitic infections in the current investigation was 65.7% including all gastrointestinal parasitic species. e
Soil transmitted infections were low in other reports such as Babile town, Ethiopia (<1%) [30], Enderta, Ethiopia (7%) [31], Sao Tome and Principe (11%) [11], and Ambo town, Ethiopia (13%) [32]. e present study gave a lower prevalence of soil-transmitted helminth infections than reports from other areas in Ethiopia such as Jima zone around Gilgel Gibe Dam (44%) among the general community [33], and Jima Arjo (46.7%) among school children [34]. Differences could emanate from variations in the habit of wearing shoes, sources of drinking water, climate, socioeconomic status, habit of clipping and cleaning fingernails, habit of eating raw/unwashed vegetables, waste disposal systems, parasitological methods, and other unknown/undiscovered risk factors.
In the current study, logistic regression showed that sexes were not associated with intestinal parasites. Hailegebriel [10] has reported similar results before from Bahir Dar area of Ethiopia. In Iran, on the other hand, male gender was significantly associated with intestinal parasites [54]. Using river water was significantly associated with these parasites, as was reported before in Ethiopia from North Gondar [35] and from Arba Minch town [18]. Tap water is safer as it may be chlorinated, while river water gets contaminated with animals and humans. Income was another predisposing factor, as poverty may lead to an unhygienic environment, lack of clean water, improper clothing, and poor nutrition [39]. Raw meat consumption also significantly contributed in a similar manner reported before [35].

Conclusion
Intestinal parasitic infections were confirmed as common health problems among the Jaragego town school-age children in Ethiopia. Entamoeba histolytica/dispar, G. lamblia, and hookworm infections were the most common intestinal parasites. High prevalence of these parasites indicates poor disposal of waste, poverty, contaminated water supply, consuming raw meat, etc. Deworming programs, sanitation of the school environment, latrines for males and females, improving water supply, and education of the general community should be launched.

Data Availability
Data are available from the corresponding author upon request.

Consent
All parties including authors agree to its publication in the current form.

Authors' Contributions
e senior author (MW) identified the existing gap in knowledge, conceived the research idea, formulated the design, participated in field and laboratory work, analyzed the data and helped interpret the findings, and eventually wrote the paper. e second author (SG) wrote the proposal, conducted the field and lab work, collected data, and wrote the draft results.