Identification of Schistosoma Mansoni Eggs and Other Soil Transmitted Intestinal Parasites in Stool using Odongo-Aginya Method

Identification of Schistosoma Mansoni Eggs and Other Soil Transmitted Intestinal Parasites in Stool using


Introduction
World health organisation (WHO) recommends Kato-Katz thick smear techniques for quantification of S. mansoni eggs and other soil transmitted intestinal parasites [1].In Kato-Katz technique, prepared thick smear of stool specimen in 1% malachite green, requires 1 to 2 hours to examine the slide for clear visibility of the parasite eggs and larvae [2].The major challenge with this method is that, during the waiting hours for better visibility of the parasite eggs and larvae, parasites eggs with thin cell walls are over cleared and the morphologies are distorted and this makes it difficult to identify and differentiate the parasites from artefacts [3].
There have been methods developed to overcome the major challenges in Kato/Katz [4] One of these methods is the Odongo-Aginya method; the compound stain comprising of 7.5% nigrosin in 10% formalin mixed 1:1 with 5% eosin yellow in 10% formalin used in this study to identify and illustrate morphological appearances of the eggs of S.
Mansoni and other intestinal parasite eggs, cysts and larvae.In Odongo-Aginya method the slides are read immediately they are prepared and the eggs are clearly distinguished from artefacts and these are maintained for a long time as illustrated in the results of comparative studies [4].

Study population
This study was conducted among selected primary school children in Lira District Northern Uganda between the months of March to May 2017.It was a cross sectional study and purely evaluating the prevalence of Schistosoma mansoni in the post national control program.

Ethical Approval
The study was approved by Gulu university research ethics committee (GUREC no.04/03/2017).Further approval from the District Health office, District Education office and head teachers of the selected primary schools were sought.Written consent was obtained from participants or their guardians.All infected children with S. Mansoni and other soil transmitted intestinal parasites were treated with a single oral dose of praziquantel 40mg/kg body weight while other soil transmitted helminths were treated with single oral dose of 500mg of Albendazole at no cost.

Sample Preparation
Stool specimens were strained through a stainless steel sieve mess size 0.315mm (Analysensieb 56557HAAN W. GERMANY).The strained stool was transferred to fill a template measuring approximately 41.7 mg of faeces, put on the microscopic slide.Three slides were prepared for each specimen and a drop of Odongo-Aginya stain (about 10-50µl) was added to each of the measured stool on the slides and stirred in using an applicator stick [4].A cellophane cover slip cut in 2x4cm, presoaked in 50% glycerin was picked with a pair of forceps and excess glycerin on it blotted out on an absorbent paper.This cellophane cover slip was then placed on the stained stool on the slide.The slide was inverted upside down and pressed down gently on tissue paper to spread out the stool smeared on the slide and to remove excess stain from the slide.The slide could have been examined immediately at field research but the prepared slides were stored in cool dry place to be examined later [4].
J Microbiol Lab Sci 3

Results
A total of 532 stool samples were examined.The fresh stool specimens were prepared in respective primary schools studied and examined at Atek Diagnostic Centre (ADC) Lira.The eggs of schistosoma mansoni and other intestinal parasites were illustrated using the Odongo-Aginya method in stool (Figure 2).In summary, the prevalence of Schistosoma mansoni was (190) 35.7% indicating a moderate infection.There were also low grade rates of infection 13.7% with other intestinal parasites like Ascaris lumbricoides 16.4%, Hookworm 12.3%, Enterobius vermicularis 8.22%, Strongyloides stercolaris larva 4.1%, Trichuris trichuria 2.7% and Hymenolepis nana 1.4% respectively.The photographs of the eggs and larvae were taken using a digital camera mounted on Olympus binocular microscope CX 21 at ADC -Lira.
Courtesy of professor Odongo-Aginya the author of the new diagnostic method.

J Microbiol Lab Sci 2 Keywords:
Identification, Schistosoma Mansoni, Soil Transmitted Helminths, STH, Intestinal Parasites, Stool, Odongo-Aginya Method List of abbreviations: ADC Atek Diagnostic Centre; DEO District Education Office; DHO District Health Office; GUREC Gulu University Research Ethics Committee; LRRH Lira Regional Referral Hospital; MOH Ministry of Health; WHO World Health Organization Volume 2 | Issue 1 ScholArena | www.scholarena.com