Description of identified studies
The review of electronic databases and reference lists from relevant studies yielded 782 potential articles. After excluding 473 articles because of duplication, the remaining articles were screened based on the pre-set eligibility criteria. Then, after reviewing the titles and abstracts of 309 articles, 245 articles were excluded. From the remaining 64 articles, only 30 articles were found eligible and included in the final meta-analysis after reading the full texts and assessing for meeting the inclusion criteria (Figure 1).
Characteristics of original articles
As described in Table 1, summarizes the characteristics of 30 articles included in this systematic review and meta-analysis. All studies included were cross-sectional design. The sample size of the included studies range from 172 (in Addis Ababa) (19) to 2372 (in Bahir Dar and Mecha District) (20). A total of 14,455 primary school children with a response rate of 97.8% participated to estimate the pooled prevalence of IPI. Of the total nine regions and two city administrations, five regions and one city administration were include; specifically, Addis Ababa (19), Amhara (15, 20-33), Oromia (34-37), Tigray (38, 39), SNNPR (40-45) and Benishangule Gumuz (46). The highest prevalence (81.0%) was reported in a study conducted in Chencha town, Gamo Gofa Zone (SNNPR) (41) while the lowest prevalence (10.9%) was noted from a study in Gondar town, North West Ethiopia (Amhara) (26). All articles were identified by exhaustive search and re-assessed all the studies before analysis.
Species of intestinal parasitic infection
The highest prevalent IPI species among primary school students were Entamoeba spp. with a prevalence of 16.11 % (95% CI: 10.79, 21.43) followed by Ascaris lumbricoides 13.98% (95% CI: 9.30, 18.67) whereas the least prevalent parasite reported was Strongloids stecolaris 1.56% (95% CI: 0.88, 2.24) (Table 2).
The pooled prevalence of at least one IPI among primary school children was found to be 46.09 (95% CI: 38.50, 53.68) (I2 = 99.0%, p<0.001) (Figure 2). Since there was high heterogeneity (I2 = 99.0%).
We performed subgroup analysis by region where the study conducted to deal the source of heterogeneity. The highest prevalence was observed in Tigray region with a prevalence of 66.6 % (95% CI: 55.5, 77.7), followed by SNNPR 50.8% (95% CI: 33.1, 68.5) and the lowest was noted in Oromia region 27.58% (95% CI: 18.6, 36.6). In addition, we conducted subgroup analysis by sample size below and above mean. The prevalence of IPI was relatively similar to the overall pooled prevalence across the category above and below the mean sample size 45.99% (95% CI: 36.68, 61.48). Finally, subgroup analysis was done for publication year, with the finding that before 2017 higher prevalence was seen compared to studies published after 2017(inclusive) (Table 3).
To determine the extent of publication bias, we performed the funnel plot for symmetry by visual inspection, and it appeared quite symmetrical (Figure 3) indicating the absence of publication bias. To confirm the status of publication bias we also performed Egger’s objectivity test, which also did not show presence of publication bias (p> 0.758).
Factors associated with intestinal parasite infection
In this systematic review and meta-analysis; hygiene of fingernail was reported from seven articles, place of defecation (6), latrine availability (7), maternal education (8), residence (4), habit of shoe wearing (11), source of drinking water (9), hands washing habit (7), and habit of washing fruit and vegetables (3) were statistically associated with IPI. However, family size reported from five articles, sex (15), age of children (11), habit of eating raw meat (4), habit of swimming (7), habit of eating raw vegetables (5), hand washing before meals (3) and waste disposal sites (3) were not significantly associated with IPI (Table 4).
The association between shoes wearing habit and intestinal parasitic infection was determined from elven articles with sample size of 6,229 (16, 17, 23, 29, 32, 33, 36, 37, 42, 43, 46, 50). Thus, we found those individual who do not regularly wear shoes was 2.7 times more likely to develop IPI (OR: 2.66, 95% CI: 1.79, 3.97) as compared to those who habitually wear shoes (Table 4).
The association between fingernail hygiene and intestinal parasitic infection was determined from seven studies with a sample size of 5,155(16, 21, 23, 29, 37, 50, 51). The result of this analysis shows significant association between fingernail hygiene and IPI. The likelihood of parasitic infection is 2.4 times higher among students who had no fingernail hygiene as compared to their counterparts who have good fingernail hygiene (OR: 2.37, 95% CI: 1.67, 3.35) (Table 4).
The association between washing fruits and vegetables and intestinal parasitic infection was determined from three papers with a sample size of 945 participants (33, 43, 52). The result of this analysis showed that significant association. Students not washing fruits and vegetables were 68% (OR: 1.68, 95% CI: 1.23, 2.30) more likely to be infected by intestinal parasites as compared to their counterparts (Table 4).
The association between maternal education and intestinal parasitic infection was determined from eight articles with sample of 3,279 participants(23, 32, 37, 41, 44, 46, 48, 52). The finding of meta-analysis indicates the significant association between maternal education and IPI. Those students who had an educated mother were two times less likely to be infected by intestinal parasite (OR: 2.02, 95% CI: 1.17, 3.48) as compared to uneducated one (Table 4).
The association between Defecation habit and intestinal parasitic infection was determined from six studies with 4,337 participants (17, 20, 29, 32, 33). The finding of meta-analysis indicated significant association between the defecation habits and IPI. Students who had open defecation was 2.7 times (OR: 2.67, 95% CI: 1.64, 4.37) more likely to be infected by parasites as compared to those utilizing latrines (Table 4).
The association between hand washing habits and intestinal parasitic infection was determined from six studies with a sample size of 4,337 (16, 20, 21, 29, 32, 33). We had found significant association between hand washing and IPI. Students, who did not have regular hand washing habits, had more than a triple the likelihood (OR: 3.45, 95%CI: 1.85, 6.47) of being infected by intestinal parasite as compared to those participating in regular hand washing (Table 4).
The association between residence and intestinal parasitic infection was determined from four articles with 1,295 participants (17, 19, 32, 42). Those who live in the rural area were 87% (OR: 1.87, 95% CI: 1.45, 2.41) more likely to develop IPI as compared to those living in urban areas (Table 4).
The association between IPI and source of drinking water were determined from nine articles. Source of drinking water is statistically associated with IPI. Thus, students who drank water from non-pipe sources were 99% (OR=1.99, 95% CI: 1.99, 2.79) more likely to become infected with parasite as compared to pipe sources users (Table 4).
The association between IPI and latrine availability was determined from seven studies. We found latrine availability is statistically associated with IPI, with students who had no latrine being four times (OR=4.39, 95% CI: 2.50, 7.73) more likely to be infected by intestinal parasites as compared to those with latrine availability (Table 4).