Frequencies of gastrointestinal parasites among students of primary school in Al Kalakla Locality, Khartoum State, Sudan: a cross-sectional study

Study area and design

This study is a cross-sectional study conducted in the locality of Al-Kalakla in the state of West Khartoum. This study was carried out between December 2016 and May 2017.

Study population

The study population was children at a primary school (Saeed primery boys school, Ebaid Khatiem primery boys school, the martyr Abdulsalam primary girls school and Ebaid Khatiem primery girls school), between the ages of 6 and 14. The purpose of the study was explained to the guardians, students and head of school and a total of 134 participants agreed to participate in this study, they were selected randomly. The children were split into three age groups (6–8, 9–11, 12–14 years) and the same number of male and female participants was selected (n=67 of each). A labeled, large-mouth stool container was given to each selected student for collection of fecal samples. Samples were collected during the school day, all samples were subjected to examine by direct smear examination, formal ether concentration technique and Saturated sugar flotation technique.

Direct smear examination

Wet preparation was achieved by blending a small part of the stool sample taken with a wooden applicator with a drop of normal saline on a slide. The sample was enclosed with a cover slip and systematically examined under a microscope using a 10X lens and elevated magnification 40X lens for further detail observation, after searching for three slides without detecting intestinal parasite, it was considered a negative result.

Formal ether concentration technique

Approximately 1 g of feces from separate areas of the specimen was gathered and emulsified in glass beaker in 5 ml of formal saline. A further 5 ml were added and mixed from the same solution. The resulting suspension was strained through a strainer. The filtered sample was poured back into a centrifuge tube and an equal quantity of ether was added. The tube was shaken by hand for 1 min and then centrifuged at 2000 rpm for 5 minutes. The upper three layers were removed and the sediment was transported to a slide covered with a cover slip and examined at 10X and 40X magnification under a light microscope.

Saturated sugar flotation technique

Approximately 100 ml of saturated sugar solution (dextrose) was put into a glass measuring cup and approximately 1 g of stool sample was added. The fecal sample was blended with the saturated sugar solution for flotation. The fecal debris was filtered into another cup and the remaining fluid was drawn out. The preparation that was filtered was poured into a glass test tube. To the top of the tube was added fecal flotation solution. A cover slip was placed on the top of the tube. The pipe remained unchanged for 15 to 30 minutes and the covering glass was closely put on a slide and microscopically examined¹².

Identification of parasites

E. histolytica, G. lamblia and Entamoeba coli were identified by presence of a cyst or trophozoite in the stool. Taenia spp., Schistosoma mansoni, Ascaris lumbricoides, and Hymenolepis nana were identified by presence of eggs of each helminth in the stool.

Data analysis

Data were analyzed using Statistical Package for Social Sciences (version 16). Using Chi square test, the significant obtained when P < 0.05. Data were presented in tables.

The sensitivity and specificity of each technique was calculated using the two formulae below:

$$\text{Sensitivity}\text{=}\frac{\text{positive}\text{cases}\text{of}\text{tested}\text{technique}}{\text{positive}\text{cases}\text{of}\text{reference}\text{technique}}\text{×}100$$

$$\text{Specifity}\text{=}\frac{\text{negative}\text{cases}\text{of}\text{tested}\text{technique}}{\text{negative}\text{cases}\text{of}\text{reference}\text{technique}}\text{×}100$$

Ethical consideration

Ethical clearance for this study was obtained from Committee of medical laboratory science, Sudan University of Science and Technology, ethical approval number (MLS – IEC – 08 – 16). Written informed consent for participation and publication of the data was obtained from the guardians of all participants included in this study.

Overall occurence of intestinal parasites

Analysis showed that 48 of the 134 stool samples collected from participants were positive for gastrointestinal parasites in Al-kalakla locality, Khartoum state. This was an overall prevalence rate of 35.8%. Infection statuses of all participants, alongside the methods used to identify infection, are available as Underlying data¹³.

Occurence of intestinal parasite by variables

The research disclosed that in females the occurrence of gastrointestinal parasites was 38.8% while in males it was 32.8%. The difference in gender rates was found to be statistically insignificant (P=0.471; Table 1). Findings showed that age groups 6–8, 9–11 and 12–14 years had parasite prevalence rates of 26.4%, 36.3% and 53.8%, respectively. These variations in rates at P = 0.057 (Table 2) were statistically insignificant. The prevalence of different parasites was found as follows: E. histolytica (16.4%), H. nana (10.4%), E. coli (7.5%), A. lumbricoides (5.2%), S. mansoni (5.2%), G. lamblia (3.7%) and Taenia spp. (1.5%) (Table 3). The results showed that 28 (20.9%) were infected with single parasite and that there were 20 infected with more than one parasite (14.9%) (Table 4).

Correlation between parasitological techniques

The frequency of gastrointestinal parasites by various parasitological methods was as follows: 35.8% by formal concentration method, 17.9% by the wet preparation method and 16.4% by the saturated sugar flotation method. A comparison between the detection rate of each method found that detection rates were significantly different (P = 0.000; Table 5).

Sensitivity and specificity of techniques compared with formal ether

Assuming that the formal ether concentration technique was the gold standard, the sensitivity and specificity of the wet preparation technique was 50% and 100% respectively, and the sensitivity and specificity of the saturated sugar flotation technique was 45% and 100%, respectively (Table 6).

Underlying data

Figshare: Hala and Ahmed file.sav. https://doi.org/10.6084/m9.figshare.9804869.v1¹³.

This project contains the following underlying data:

Data are available under the terms of the Creative Commons Zero “No rights reserved” data waiver (CC0 1.0 Public domain dedication).