Corresponding Author: Biyaya Beatrice Nwankwo1, Adebowale Ernest Onifade2
1 Department of Community Medicine, University of Abuja, Abuja
2 University of Abuja Teaching Hospital Gwagwalada
Schistosomiasis or bilharziasis was named after Theodore Bilharz a German surgeon who worked in Cairo. He was the first person to identify the aetiological agent Schistosoma haematobium in 18511.Urinary schistosomiasis is a chronic inflammatory disease that affects urinary bladder caused by the schistosomes (eggs) laid by the helminth Schistosoma haematobium.2
The aim of the study was to determine the prevalence and intensity of urinary schistosomiasis among primary school children in Angwan-dodo community.
A multistage sampling method was used.Using a sterile universal bottle, urine samples were obtained from the subjects and transported immediately to the laboratory for analysis.
A total number of 336 samples were examined for the presence of the ova of Schistosoma among children within the ages of 6-17years in Angwan Dodo.Mean egg intensity was 30.0 ± 17.2 standard deviation(SD) with highest intensity being 59 eggs/10ml and the lowest 8 ova/10ml. The age group 12-14 years had the highest prevalence rate(19.6%) and highest mean ova intensity (33.9 ova/10ml urine) while the age group 6-8 years had the lowest rate. Overall, light intensity was (7.4%) while heavy intensity was (2.7%). Among those infected, light intensity (73.5%) was significantly higher than heavy intensity (26.5%). There was statistical significance in the prevalence (P = 0.002) in relation to age group however, no significance in mean intensity (P > 0.05 among the age groups.
Higher prevalence of infection was seen in the public school (15.6%) children compared to private schools with statistical significance (P = 0.003) but there was no statistical significance in the mean intensity between them (P > 0.05). Boys had the higher prevalence (15.9%) than girls (4.2%) respectively with statistical significance between them in prevalence (P = 0.002).
Keywords: Schistosoma heamatobium, Anguwan Dodo.
Schistosomiasis or bilharziasis named after Theodore Bilharz a German surgeon who worked in Cairo, he was the first person to identify the aetiological agent Schistosoma haematobium in 1851, and Schistosomiasis is a parasitic infection caused by the schistosomes or blood flukes that belong to the class Trematoda of the Phylum Platyhelminths.1
Urinary schistosomiasis occurs as a result of chronic inflammation of the urinary bladder caused by the presence of schistosomes (eggs) of the helminth Schistosoma haematobium.2 The other species of schistosoma such as japonicumand mansonicause chronic inflammatory disease of the liver and intestines respectively.2 Although, infection with schistosomes do not always result in clinical manifestation, thus many infections are asymptomatic, infected individuals could however present with blood stained urine (often called male menstruation in men), painful micturition, and increased frequency of micturition2. Other major clinical presentations by infected individuals include; anaemia, nutritional deficiencies, poor growth, renal impairment, and bladder cancers later on in life.3
Schistosomiasis isone of the Neglected Tropical Disease as classified by WHO, it is estimated to affect about 200 million people worldwide with over 700 million people at risk of getting infected with Sub-Saharan Africa bearing the greatest burden of the disease (93%), thusmaking it one of the most important parasitic infections in the tropics, coming second to Malaria affecting children more than adults with high morbidity and mortality amongst them.4,5
The disease is endemic in the following African countries Ethiopia, Kenya, Cameroon, Uganda, Malawi, Mozambique, among others.6In Sub-Saharan Africa, it is endemic in Tanzania(19%), Ghana and DRC Congo (15%).7 In Nigeria alone, the prevalence of urinary schistosomiasis between 1994-2015 was estimated to be 34.7%.7
Previous studies done in the Federal Capital Territory showed prevalence of between 25-36.5% in typical communities with close proximity of human water contact activities such as playing and swimming in polluted rivers, washing and fetching water for house hold use, making them very vulnerable to infections, this is coupled with the fact that these communities lack or are in shortage of potable water supply, poor environmental sanitation, poverty, and ignorance8.
Several diagnostic procedures detect urinary schistosomiasis infection, this range from simple use of questionnaires to ask for blood in urine, physical inspection of urine for blood, and dipsticks to more complex procedures such as sedimentation technique, immunological techniques and the DNA PCR. For prevalence studies the sedimentation technique is the most widely used because of its simplicity and cost effectiveness10.
The most important method of control of transmission to break the cycle at various points which include; provision of safe water, proper sanitation, snail control, mass treatment with praziquantel, and health education on risk the factors and preventive measures9.
Aim and objective
To determine the prevalence and intensity of urinary schistosomiasis among primary school children in Angwan-dodo community.
The study was conducted in Angwan-dodo a small semi-urban community in Gwagwalada area council of the Federal Capital Territory. It is bounded on the south-west by River Gwagwalada and on the east by Abuja-Lokoja road separating it from the main Gwagwalada town.
There is scarcity of data on the population characteristics of this community. The major inhabitants of the community are the Bassa, Gbagyi, Nupe people who are mostly uneducated with a mixed population of various other ethnic groups such as the Igbo’s, Hausa’s, Yoruba’s, and other minority ethnic nationals of Nigeria. Fishing is the predominant occupational activity carried out mainly by the Bassa people. Other recreational and domestic activities carried out in the river include; swimming, playing, bathing, washing, and defecation.
The river is most patronized during the dry season like (January to April) when there is scarcity of rain to provide water for household use.
The community has only one public school (LEA primary school) which is quite some distance away from the river with several small private schools scattered all over the community. There are reports of a high number of children mostly from the public school going to swim and play in the river after school hours. The community has no public health care centre but has patent medicine stores and private clinics that are run by non-doctors. Due to inadequate safe water supply to the community, the people depend on the river, well water and water vendors popularly known as the “Mairuwa” who get water from unknown source to sell to people in the community. Finally, the sanitation practices of the people are poor as refuse dumps litter the streets.
The study population were primary school children between ages 6 to 17 within Angwan-dodo community of the one public primary school (LEA) in the community and over 15 private schools. The total population of school children in the community was about 2500.
A multistage sampling method was used.
Stage one was the selection of central ward from the ten wards in Gwagwalada Area Council using a simple random sampling method by way of balloting.
Stage two was the selection of Angwan-dodo community from among the 4 communities in the previously selected ward bordering Gwagwalada River using a simple random sampling.
Stage three was the assembling of all the schools in Angwan-dodo and stratification into private and public, then the selection of five private schools from the 15 private schools in Angwan-dodo using a simple random sampling method by balloting without replacement, and the only public school in the community, bringing the total number of schools to 6.
Half of the sample size (175) was selected from the five private schools (35 per school) while the remaining half (175) was selected from the only public school in the community (LEA primary school)
In each school, all the classes were stratified, and within each class participants were selected using the simple random sampling technique by balloting without replacement. Proportionate allocation was also used to select the required number of participants in each class.
Data Collection and sampling process
The procedure was explained to the subjects (study participants) and a number was assigned to each subject. Terminal urine samples (20ml) were collected into a labelled sterile universal bottle. Samples were collected between 10:00am and 2:00pm after a mild physical activity, as this coincides with the circadian rhythm of the eggs excretion in S. Haematobium Samples were collected within the school premises with the help of the teachers for the much younger age subjects. The samples were transported to the laboratory and immediately analysed.
Macroscopy examination of the urine samples for haematuria was done,followed by microscopic examination of the sediment after centrifugation of the urine sample. 10ml of each urine sample was poured into a test tube and then centrifuged for 5 minutes at 3000 rmp (revolution per minute) after which the supernatant was decanted and the sediment containing was examined under a light microscope at 10x and confirmed with40x objective.
Sample that showed the presence of ova of Schistosoma was recorded as positive while that without ova of Schistosoma was recorded as negative. For the positive samples, the ova was counted and each average count was recorded as number of ova’s/10ml of urine sample and categorized into light intensity (<50 ova/10ml of urine) and heavy intensity (≥50 ova/10ml of urine).
A total of 336 respondents were studied with majority of the respondents being, 170 (50.6%) males,Mean age of the study population was 10.3 ± 2.3 years, with majority (44.3%) falling within 9-11 years age group,Based on ethnicity, majority of the respondents, 66 (19.6%) were Igbo by tribe while Bassa made up 8.3% of the respondents.
Mean ova intensity was 30.0 ± 17.2 SD with highest intensity being 33.9 ova/10ml and the lowest 8 ova/10ml. Highest prevalence of Schistosoma haematobium was in age group 12-14 (19.6%) so also was the mean intensity (33.9 ova/10ml urine) while prevalence was lower in age group 6-8 yrs. Overall, Light intensity was (7.4%) while heavy intensity was (2.7%). Among those infected, light intensity (73.5%) was significantly higher than heavy intensity (26.5%). There was statistical significance in the prevalence (P = 0.002) in relation to age group however, no significance in mean intensity (P > 0.05) among the age groups.
Higher prevalence of infection was seen in the public school (15.6%) compared to private schools with statistical significance (P = 0.003) but there was no statistical significance in the mean intensity between them (P > 0.05).
Figure 1: Prevalence in relation to ethnicity
Highest prevalence was observed among the Nupe respondents (19%), Gbagyi (17.6%) and Idoma (14.8%) ethnic groups while lowest prevalence was among Ebira, Egun, and Edo ethnic groups (0%). However, no statistical significance in prevalence amongst them.(P > 0.05).
Figure 2: Prevalence in relation to religion
Pupils who lived very near the river had the highest prevalence (13%) while pupils living outside Angwan-dodo had the lowest prevalence (0.0%). However, there was no statistical significance in prevalence in relation to closeness to the river. (P > 0.05).
Prevalence and intensity
In this study the overall prevalence of urinary schistosomiasis was found to be 10.1%, this prevalence rate is classified by WHO as moderately endemic (>10% <50%)11. This study has revealed that there is no much change in prevalence compared to the earliest study done in Gwagwalada 23 years ago which showed a prevalence rate of 10.3%12, however the prevalence is much lower than what was reported (31.3%) in the FCT 9 years ago by Casmir IC etal 8. Other studies reported prevalence rate of 55.0% in Guma Benue13, 30.5% in Keffi Nasarawa14. The finding is however higher than 1.5% as reported by Akpan S.S etal in Ikom Cross River15. Compared to findings in other African countries, the prevalence in this study is higher than that reported in Malawi (6.9%)16, but lower than findings in Kumba Cameroun (32.1%)17and Zimbabwe (60%)18.
The mean egg intensity in this study was found to be 30.0 ± 17.2 SD with highest intensity being 59 eggs/10ml and the lowest intensity of 8 eggs/10ml. Other studies by Atalabi et alreported mean egg intensity of 25.0 eggs/10ml urine ± 71.5 SD around Zobe dam Kastina19, 1.11eggs/10ml urine in Abeokuta Ogun by Ekpo UF20.
Among infected subjects, prevalence of light intensity of infection (73.5%) was significantly higher than heavy intensity (26.5%) and this is similar to other studies that reported a higher prevalence of light intensity (86.6%) relative to heavy intensity (13.3%) in Guma Nasarawa13, light intensity (55.3%), heavy intensity (44.7%) in Ajase-Ipo Kwara21, light intensity (94.4%), heavy intensity (5.6%) around Abua Rivers22.
Prevalence and intensity in relation to age and sex
Highest prevalence of S.haematobium was in age group 15-17 (25.0%) followed by age group 12-14 (19.6%) with statistical significance. Other studies reported highest prevalence among age group 6-12 years in Gwagwalada Abuja12, 9-12 years (19.1%) at Abua Rivers state22, 9-12years (2.6%) in Ikom Cross River15, 13-15 years (67.5%) around Zobe dam Kastina19, and 11-13 (24.8%) in Nguru Yobe23.
Highest mean intensity (33.9eggs/10ml urine), Light intensity (13.0%) and heavy intensity (6.5%) were in age group 12-14 years however, with no statistical significance in mean intensity (P > 0.05). A study done around Zobe dam Kastina reported highest mean intensity of 28.9eggs/10ml urine among children within age group 10-12years with statistical significance (P<0.05)19. Other studies reported a higher intensity among age groups 9-12years (15.6%) in Ajase-Ipo Kwara22, 11-15years (27.8%) Guma Nasarawa13 with no statistical significance (P>0.05).
Boys had a higher prevalence (15.9%) and mean intensity(30.7eggs/10ml urine) compared to girls (4.2% prevalence with mean intensity 27.1eggs/10ml urine) with statistical significance of (P=0.001) but no significance in mean intensity (P>0.05) between them. This is comparable to a similar study done around Zobe dam Kastina which reported a higher prevalence (55.8%) and intensity (28.7 eggs/10 ml of urine) among boys compared to girls (2.83 eggs/10 ml of urine).19Similarly studies done in Ajase-Ipo Kwara22, Guma Nasarawa13, and Ezza-North Ebonyi corroborated this findings.24 However, some studies reported equal to or higher prevalence among girls (59.2%) than in boys (57.1%) in Abeokuta Ogun25,girls (15.5%) and boys (15.0%) in Keffi Nasarawa14 with no statistical signifcance. Possible explanation for the higher prevalence and intensity in boys than girls could be attributed to the adventurous nature of boys.
Prevalence in relation to ethnicity
Based on ethnicity, the highest prevalence was observed among the Nupe respondents (19%), Gbagyi (17.6%) and Idoma (14.8%) ethnic groups. However, there was no statistical significance in prevalence amongst them. (P > 0.05).Though majority of the study participants were Igbo’s, (19.6%) there was zero prevalence of infection in this ethnic group. The Bassa’s are one of the predominant ethnic groups in the community made up of 8.3% of the respondents with the prevalence of urinary schistosomiasis amongst them at (10.7%).
Overall prevalence of urinary schistosomiasis was 10.1%with amean egg intensity of 30ova/10ml urine sample ± 17.2SD. Light intensity (73.5%) was significantly higher than heavy intensity (26.5%). Similar to other studies, this study identified age, sex, type of school, the highest prevalence of urinary schistosomiasis was seen among pupils in age group 15-17 (25%), boys (15.9%), children in the public school (15.6%).
Based on the findings of this study, an integrated approach to the eradication of urinary schistosomiasisis recommended to the Government, the schools and the community as follows-:
Creation of public awareness on the dangers of this disease and its mode of infection is important towards the control of schistosomiasis
Creation of barrier to prevent the children from gaining access to play in the river
Provision of sustainable chemotherapeutic intervention with Praziquantel® to reduce its prevalence below the threshold of public health significance.
The authors wish to acknowledge and appreciate the cooperation of those school children that make up the study population
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