Epidemiological investigations on the occurrence of intestinal parasitic infection and associated risk factors in primary school students are necessary to design appropriate intervention strategies. This study determined the prevalence of intestinal parasitic infections and associated factors among mentally disabled and non-disabled primary school students in Bahir Dar, Amhara Regional State, Ethiopia. The study revealed that 56.7% (95% CI: 47.2-66.2) of mentally disabled and 41.1% (95% CI: 35.7-46.5) non-disabled primary school students were infected with intestinal parasitic infections. Prevalence of intestinal parasitic infections was higher among mentally disabled students than non-disabled students with point estimate for the difference is 15.6% (95% CI: 0.05, 0.27). This suggested that mental disability can directly influence hygiene and safety habits and, consequently, favor the acquisition of intestinal parasitic infections.
The prevalence of IPI among mentally disabled students in this study 56.7% was higher than else studies conducted in Rasht, Northern Iran (5.15%)(17), Brazil (8.3%)(18), Tanzania (12.45%)(19) and Egypt (43.5%)(10).Because it might be due to poor shoe wearing practices, poor hand washing habits, open defecation practices, poor personal and environmental hygiene and limited health checkup.
In another way, this study was lower than the study conducted in Iran among elderly and mentally retarded residence (78.7%)(20).This might be due to the fact that the study participants in the latter study is carried out among elderly individuals in the community while the current study done on mentally disabled students at school which indicate most of the mentally disabled students at school may had better follow-up on their personal hygiene and sanitation through teachers and guardian than elderly mentally disabled individuals in the community which directly affect the prevalence of intestinal parasitic infections.
Similarly, the prevalence of IPI among non-disabled students in this study (P=41.1%, 95% CI: 35%-46.2%) was similar with a previous study conducted in Turkey 44.6% (21), Southern Ethiopia 39.9% (22)and in Amhara Region, Tillili (44.2%)(23). However, this finding was lower than most studies done worldwide (Peru 47% (24), Argentina 78.3%(25) and Yemen 54.8%(26)) in Africa (South Africa 64.8%(27), Rwanda 50.5%(28), Sao Tome 64.7%(29) and Tanzania 48.7%(30)) and in Ethiopia,(Chencha Town, 81%(31), Jimma, 48.4%(44), Mizan Aman Town, 76.7%(45) and Bahir Dar 65.5% (16)). The most possible reasons were an improvement in proper and protected drinking water supply, better shoe wearing practices at school and improvement on personal and environmental hygiene and sanitation.
In addition to determining the PIPIs, this study also predicts various predictors of intestinal parasitic infections among mentally disabled and non-disabled students.
The study revealed that unclean fingernails/having dirty materials in fingernails made students be more infected with intestinal parasites (AOR=2.416;1.400,4.168). A Comparable association of intestinal parasitic infection with the availability of dirty material in fingernail were reported in different studies conducted in different period time and different parts of Ethiopia(16, 32-35). This could be described by the availability of dirty materials in fingernails may lead to direct feco-oral transmission of intestinal parasite or it uses as habitat to proceed the life cycle of soil-transmitted intestinal parasites.
The previous medical checkup was one of predictor variable for intestinal parasitic infections. Students who had not any medical checkup previously were more likely to be infected with intestinal parasites than students who had medical checkup previously (AOR=1.869;1.156,3.023), Which is in line with a study conducted in Aksum, Ethiopia (36). This might indicate mentally disabled students who visit health institution with his/her parents or guardian had a tendency to decrease intestinal parasitic infections through increasing his/her health, safety, and personal hygiene.
The risk of acquiring infections among students who used water only during hand washing was 2.476times higher than among those who used water and soap during hand washing (AOR=2.476;1.489,4.119) which is congruent with earlier studies conducted in Ethiopia (37, 38).This might due to using water only didn’t sufficient to keep our safety and hygiene, so students must use water with soap to remove infective stage of the parasite or dirty materials from those hand.
Students whose household cooking and sanitation water source from both (well and tape) were 4.4 times more likely to develop IPI than students whose source of water from tape water only (AOR=4.404; 2.319, 8.364), this result also inconsistent with (16, 37, 39). The possible explanations of association of water source and increase parasitic infection might be due to an increased chance of contamination of well water by infective stages of different intestinal parasites.
The probability of being infected by intestinal parasites was increased by about 2.74 folds among students belonging in a family size of >=7 as compared with students belonging in <=3 family size (AOR=2.736; 1.249, 5.994). Other studies in agreement with this study conducted in Ethiopia were (18,43) and (34). This association might be due to the fact that personal hygiene, environmental sanitation, and other nutritional related problems. As a family size increase, there might be a problem of overcrowding, under nutrition, poor sanitation, and personal hygiene which enhance intestinal parasitic infection susceptibility.
Furthermore, males were 1.642 times high risk for intestinal parasitic infections than females (AOR=1.642; 1.026, 2.627). This is comparable with a study conducted in Southwest Ethiopia (37). Male students usually play outdoors and participate in outdoor activities compared to females, which may enhance risks of IPI. However, this finding contradicts with another study conducted in Ethiopia (40).
Lastly, there was a significant association between the educational level of students and the rate of intestinal parasitic infections. Students in the first cycle were 2.27 times more likely to be infected with intestinal parasitic infections than those in grade level of the second cycle (AOR=2.272; 1.408, 3.666). This was in line with other studies [43, 46].This finding might be due to lack of regular health education program in the school which can decrease their awareness in the prevention and control mechanisms.
Strength and Limitation of the Study
Strength of the Study
Both wet mount and formol-ether concentration techniques were used to examine the presence of intestinal parasite from study participants stool sample which used to increase the validity of the measurement of the dependent variable.
Limitation of the Study
First, in this study, an interview was held with each student for non-disabled students while parents/guardian/ were asked about their mentally disabled children using a questionnaire pertaining to factors associated with intestinal parasitic infections.
Second, as we only examined a single stool samples by both wet mount and concentrations technique of each study participant, we might underestimate the true prevalence of parasitic infections, due to cyclical nature of life cycle of intestinal parasites, to say negative stool sample at list three consecutive samples in three consecutive days must be examined from each study participants.