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Table of Contents
RESEARCH ARTICLE
Year : 2021  |  Volume : 58  |  Issue : 1  |  Page : 63-69

A survey of urinary schistosomiasis among school aged children of ten communities in South-South, Nigeria


Department of Animal and Environmental Biology, Faculty of Life Sciences, University of Benin, Benin city, Edo state, Nigeria

Date of Submission09-Jan-2019
Date of Acceptance25-Oct-2019
Date of Web Publication18-Nov-2021

Correspondence Address:
Joseph E Igetei
Department of Animal and Environmental Biology, Faculty of Life Sciences, University of Benin, Benin city, Edo state
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0972-9062.313971

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  Abstract 

Background & objectives: Schistosomiasis is one of the major neglected tropical parasitic diseases caused by a group of blood-feeding worms in the genus Schistosoma. Nigeria ranks highest among all countries worldwide, however, there is a paucity of information on the prevalence of the disease in some parts of the country. Therefore, the research aims to augment available data on the prevalence of Schistosoma haematobium infection among schoolaged children in ten communities in Edo state, Nigeria.
Methods: A cross-sectional survey involving 400 school-aged children was conducted in 10 randomly selected communities in Akoko-Edo Local Government Area, Edo State of Nigeria between November 2016 and April 2017. Demographic data of subjects was collected using a structured questionnaire. Urine samples were collected and examined for haematuria and ova of Schistosoma haematobium using a commercially prepared reagent strip (Medi-Test Combi9TMR) and sedimentation technique respectively.
Results: The prevalence of urinary schistosomiasis based on microscopic examination of the urine sediment for the ova of S. haematobium was 17.3%, while haematuria was 22.0%. Mean intensity of S. haematobium oval count ranged between 2.0–4.0/10ml of urine per community. Prevalence was higher among males (24.5%) than females (10.0%)(P<0.05), which was statistically significant. Overall, age group 7–9 years showed the highest prevalence of infection. Farming showed a strong correlation as a parent occupational risk factor in predisposing children to infection as it accounts for 73.9% of all infections.
Interpretation & conclusion: Findings indicate that urinary schistosomiasis is still prevalent among school-aged children in Akoko-Edo LGA, which hinders their growth, development and cognitive abilities. Although, mass drug administration is ongoing in some of the communities, re-infection still occurs due to ignorance, occupational factors, lack of portable water and sanitary toilets.

Keywords: Schistosomiasis; Schistosom ahaematobium; school-aged children; public health; Nigeria


How to cite this article:
Boih LO, Okaka CE, Igetei JE. A survey of urinary schistosomiasis among school aged children of ten communities in South-South, Nigeria. J Vector Borne Dis 2021;58:63-9

How to cite this URL:
Boih LO, Okaka CE, Igetei JE. A survey of urinary schistosomiasis among school aged children of ten communities in South-South, Nigeria. J Vector Borne Dis [serial online] 2021 [cited 2021 Nov 27];58:63-9. Available from: https://www.jvbd.org/text.asp?2021/58/1/63/313971


  Introduction Top


Schistosomiasis is one of the most important neglected tropical parasitic diseases (NTPDs) of public health importance caused by a helminth in the genus Schistosoma. The parasitic disease has been reported in 78 countries worldwide and endemic in 52 of them[1]. More than 750 million individuals reside in regions endemic for schistosomiasis, for which over 200 million persons are infected worldwide, 91% of whom are in Africa[1].

A World Health Organization (WHO) report in 2018 indicated that in the year 2016, approximately 206.4 million schistosome-infected individuals required treatment for the disease. Although deaths worldwide due to schistosomiasis are difficult to estimate due to poor diagnosis and documentation, the same report indicated that it ranged between 24,067[2] and 200,000 annually[3].

Two of the six schistosome species infecting humans (Schistosoma haematobium and S. mansoni) have been reported as the dominant parasite species in Africa, causing urogenital and intestinal schistosomiasis respectively[1]. Urinary schistosomiasis is endemic in many sub-Saharan African countries where suitable habitats for Bulinus snail vectors, the intermediate host of S. haematobium are abundant and like other neglected diseases is endemic in poor and marginalised communities[4]. It is therefore seen as a disease of the poor who live in unhygienic conditions that favours transmission and those who have no access to proper healthcare[5],[6].

Urogenital schistosomiasis is associated with serious health problems and morbidities especially among women and children[1],[7]. The disease in pregnancy results in anaemia, placental complications culminating in low birth babies, increased risk of acquiring the Human Immunodeficiency Virus (HIV), bladder cancer, bladder and kidney fibrosis, vaginal bleedingand genital lesions[1]. Children on the other hand suffer from anaemia, malnutrition, poor growth, impaired mental and cognitive development all of which negatively impact their overall development and productivity[8].

Currently, schistosomiasis in considered to be most prevalent in Nigeria among all the nations of the world[9]. Nigeria is comprised of 36 states and 774 local government areas (LGA) with a population of about 150 million people (Nigerian Population Commission, 2006). However, up-to-date information on the prevalence of the disease in some states and communities in Nigeria is sparse, especially among children which form the most naïve and vulnerable age group and suffer the most morbidity due to the disease[10],[11]. Edostate, made up of eighteen LGAs, serves as one of the endemic states for schistosomiasis in the country, but lacks recent information on the status of the disease as only a few surveys have been reported: a prevalence of 43.3% was recorded in Enwan community[12], a prevalence of 10.7% in a community in Etsako west LGA[13], and a prevalence of 65.3%in two communities in Ovia South-West LGA[14]. Despite the existence of very favourable conditions for the transmission of urinary schistosomiasis in Akoko-Edo LGA, no comprehensive study has been conducted to determine the prevalence of the infection among the inhabitants of the region. Therefore, this study was done to determine the prevalence of urinary schistosomiasis among school-aged children in ten endemic communities of Akoko-Edo LGA of Edo State, Nigeria. Data reported herein will augment current available data, help access the effectiveness of current control programs as well as provide baseline information for implementing future control strategies.


  Material & Methods Top


Pre-survey procedures

Pre-survey visit to the villages in the study area was made, during which consultations and discussions were held with village heads, heads of health clinics and primary school teachers who assisted in mobilising the pupils for the study. Prior to commencement of the survey, the students and their parents were educated on the purpose and implication of the research which they clearly understood. Only students who gave clear consents took part in the research.

Study area and population

The study was carried out in Akoko-Edo Local Government Area (LGA), one of the eighteen LGAs of Edo State, Nigeria, between November 2016 and April 2017. Edo state has a mixed-climate ranging from tropical rainforest to savannah situated in the South-South zone of Nigeria. However, Akoko-Edo LGA lies in the northern part of the state (a transitional zone between rainforests and guinea savanna) with mean annual rainfall of 2200–2500mm as well as a mean annual and peak temperatures of 29°C and 35°C respectively. It is divided into ten districts and has an area of 1371km2 and an estimated population of 262,110 (Nigeria population Census 2006). Akoko-Edo lies geographically between latitude 7011’36”N–7029’54”N and longitude 5056’54”E–6033’30”E.

The inhabitants are predominantly farmers, traders and civil servants. The area is a typical rural settlement intersected by several fresh water habitats, some of which are man-made pools or burrow pits, dams, streams and rivers. Members of this community depend largely on the available streams, rivers, wells, burrow pits and rainwater to meet their water needs. The primary schools in the LGAs are scattered in the villages and because of the interception of streams among these villages, the school children usually recreate in these waters during and after school hours.

The primary schools enrolled for the study with the help and guidance of community heads and government health care workers and teachers were: Akuerohmoh (Ikpeshi), Unne (Sassaaro), Egbegere (Egbegere), Ojirami Dam (Ojirami), Akukun (Akukun), Enwan (Enwan), Etuno Model (Igarra), Unekhua (Uneme-Nekua), Idogu (Okpe) and Ajama (Ajama). Praziquantel was administered orally to infected students (40mg/kg body weight) encountered in the study with the help of healthcare workers.

Data and specimen collection

Data on socio-economic/demographic characteristics and risk factors was collected using interview-based questionnaire. Name, sex, age and health details of the student was collected and they were interviewed about their economic background, parent’s occupation, water facilities, local treatments, and previous history of parasitic infections. After orientation the class teachers assisted in collecting demographic data from school children using a structured questionnaire. Urine samples were collected from 400 primary school children (200 males and 200 females) between the ages of 5–16 yr old who consented; 40 students from each of the 10 communities took part in the study. The urine specimen from each study participant was collected in a pre-labelled wide mouthed plastic bottle (30 mL) between 10:00 am and 2:00 pm and each was placed in a black cellophane bag to protect from sunlight, thus preventing the ova of S. haematobium from hatching.

Determination of haematuria

Fresh urine samples collected from study population were observed macroscopically for visible haematuria, while microhaematuria was investigated using Medi-Test Combi 9R (Machery-Nagel, GmbH & Co, Germany) reagent strips as described by the manufacturer. Briefly, the strip was dipped into 5 mL urine sample placed in a clean test tube from the original urine collected in universal bottles. A positive control for microhaematuria was set by adding one drop of blood into 100 mL of sterile distilled water while the negative control was sterile deionized water.

Parasitological investigation

Urine sample and the ova of S. haematobium therein were preserved at the collection site by adding two drops (10% formalin) to 20 mL of specimen. At the laboratory, each sample was examined for parasite eggs using a method of sedimentation and centrifugation as described previously[10]. The sediment was transferred to a clean glass slide, covered with cover slip and examined under the microscope for terminal-spined eggs of S. haematobium with x10 and x40 objectives lens and samples positive for eggs were counted. The examination for parasite eggs and egg count were repeated on another portion of the sample and the mean expressed as eggs/10 mL of urine was recorded for each pupil.

Data analysis

Prior to entry, all demographic data were coded, entered and analysed using SPSS version 15.0 for Windows. Descriptive statistics were used to calculate the prevalence of urinary schistosomiasis and expressed as a percentage (100%). Pearson Chi-square test was used to test for any significance between infection in males and females among each of the age groups and overall. The mean S. haematobium ova intensity was derived by dividing the total number of parasite eggs by the total number infected children as recommended previously[10]. Differences and associations were considered significant at P <0.05.

Ethical statement

Ethical permits for conducting the research were sought and obtained from the University of Benin ethical committee via the head of the department of Animal and Environmental Biology, the head of the various communities, parents, teachers and students.


  Results Top


Overall prevalence and mean ova intensity of urinary schistosomiasis in Akoko-Edo LGA

A total of 400 school children were investigated in the study, for which 69 were infected, based on the presence of S. haematobium eggs/ova in urine, recording an overall prevalence of 17.3%, while the prevalence of haematuria was 22.0% [Table 1]. The overall prevalence from each of the 10 communities varied, except for Ojirami and Idogu, and ranged between 0.25%–4.50%. Pupils in Enwan community recorded the highest overall prevalence of 4.50%, while two communities (Ojirami and Idogu) recorded the least [Table 1]. Also, [Table 1] shows that prevalence at the community level ranged between 2.50%–45.0%, with the highest recorded in Enwan and the lowest recorded in two communities (Ojirami and Idogu). Furthermore, [Table 1] shows the mean intensity of ova counts among pupils who were positive for S. haematobium eggs which varied between 2.0–4.0 per 10 mL of urine. Pupils in Enwan community recorded the highest mean number of ova (4.0 per 10 mL of urine), while three communities; Ojirami, Etuno and Edogu recorded the least number of ova with 2.0 per 10 mL of urine [Table 1].
Table 1: Prevalence of S. haematobium infection and mean egg counts by community/school in Akoko-EdoLGA in Edo State, Nigeria

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Age and sex specific prevalence of urinary schistosomiasis among children in the study area

The ages of the study subjects ranged from 4 to 16 years, while prevalence of urinary schistosomiasis among the age groups ranged between 13.7%–23.3% [Table 2]. Pupils of age group 7–9 yr recorded the highest prevalence, while the 10–12 age group recorded the least. In relation to sex, males recorded a higher prevalence of infection (24.5%) than females (10.0%) which was significant (P<0.001) [Table 2]. Among males, the 7–9 age group recorded the highest prevalence (35.7%), while the age groups 4–6 and 13–16 both recorded the least (20.0%). In females, the 4–6 age group recorded the highest prevalence (18.8%), while 10–12 recorded the least (3.8%) [Table 2].
Table 2: Age and sex specific prevalence of S. haematobium infection amongst school-aged children at Akoko-Edo LGA, Edo State Nigeria

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Parent’s occupation as a risk factor for urinary schistosomiasis amongst children in the study area

[Table 3] shows the influence of parent’s occupations on the transmission of urogenital schistosomiasis among children in the study population. Overall, children whose parents are farmers showed the highest infection with a prevalence of 73.9%, followed by artisans and civil servants with prevalence of 18.8% and 7.3% respectively. In relation to farming, children in Enwan community recorded the highest prevalence (46.9%), while Okpe community recorded the least (3.3%). No infection was observed in children from Ojirami community [Table 3]. In relation to children whose parents are civil servants, five of the ten communities showed infection. Ikpeshi community recorded the highest prevalence (50.0%), while Ojirami community recorded the least (12.5%). No infection was observed in children from Egbigere, Igarra, Uneme-Nokhua, Okpe and Ajama communities. Also, [Table 3] shows that among children whose parents are artisans, no infection was observed in four of the ten communities surveyed; Ojirami, Igarra, Okpe and Ajama. Children in Egbigere and Enwan communities recorded highest prevalence of infection (50.0%), while those in Uneme-Nokhua recorded the least (8.0%). [Table 4] reveals the association of parent’s occupation as a risk factor to S. haematobium infection in relation to sex. Of the 69 infected school children in the study, males recorded a higher overall prevalence (71.0%) than females (29.0%). Also, it shows that males recorded a higher prevalence than females in all three occupations.
Table 3: Prevalence of urinary schistosomiasis based on parents’ occupation of the pupils of Akoko Edo LGA of Edo State

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Table 4: Sex and parent’s occupations as a risk factors to exposure to urinary schistosomiasis

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  Discussion Top


Schistosomiasis is one of the prevalent parasitic diseases in South-south Nigeria, however recent epidemiological data on the prevalence of the disease in some communities is lacking. Children were chosen as the study population owing to their naivety and poor knowledge of the disease. Findings herein indicate that urogenital schistosomiasis is still prevalent (17.3%) in Akoko-Edo LGA, despite some efforts of control which majorly focus on mass drug administration.

Our finding is similar with previous reports in young individuals from various states of Nigeria. In Adim community of Cross-river state, a prevalence of 14.5% was recorded[15]; a prevalence of 10.7% was recorded in children from Etsako West LGA of Edo state[13]; while a prevalence of 15.3% was recorded in 6–20 yr old individuals from Ebonyi state[16]. However, a significantly higher prevalence (65.3%) was reported in school children in Ovia South-West in Edo state[14], while a prevalence of 58.1% was recorded in preschool children close to Abeokuta in Ogun state[10].

The presence of blood in urine (haematuria), associated proteins (proteinuria) and S. haematobiumova are diagnostic markers for urogenital schistosomiasis[17],[18]. While proteinuria is associated with renal stress due to previous/current infection, haematuria is linked with current pathology. Hence, the similarity in prevalence of the latter with that of parasite ova in our study further reinforces this point, which has also been observed previously[19]. However, the low number of ova count reported in infected individuals indicate that anti-helminthic are administered to the children which they attested to (via personal communication), but due to continuous contacts with cercariae-infested water, the worm persists in them. Anti-helminthics are known to suppress egg laying by schistosome worms[12],[18].

Our findings show a strong correlation between farming as a significant occupational risk factor in contacting schistosomiasis as 73.9% of all infected children had parents who are farmers. This agrees with previous reports[16],[18],[19]. Farming is closely associated with water-contact activities such as irrigation, fishing and swimming as these individuals usually took time-off to cool their body and/ or bath during and/or after a day’s job[18]. These activities ensure regular contact with larvae-infested water as well as coincide with peak emergence of cercariae in water. Also, our findings indicate that farming predisposes male children to S. haematobium infection than females which could be attributed to their more involvement in water-related recreational and farming activities such as hunting, fishing and swimming. Previously, similar observations have been reported by the following authors[12],[16],[20]. Females on the other hand have a more restricted movement and are more indulged in home chores under the guidance of their mothers.

The prevalence of S. haematobium varied among communities (2.5%–45.0%), which could be attributed to their proximity to boreholes, rivers/streams which serve as sources of water supply for inhabitants. Generally, communities close to boreholes have less contact with infected rivers/streams and are less infected, while those closer to streams/rivers have frequent water contacts and are more infected. Previously, some authors have shown the correlation between frequency of stream visits and schistosome infection[15],[21],[22]. However, personal communication with some inhabitants in the study area revealed that some communities closer to boreholes are forced to rely on schistosome-infested streams/rivers as their source of clean water for domestic use as water from the boreholes are dirty/coloured and perceived as not hygienic enough for cooking or drinking, when compared to stream water which appears clearer and cleaner to the naked eye. The only alternative to the use of water from schistosome-infested streams is buying from vendors which is a huge luxury for people who can hardly afford two square meals per day. Hence, lack of portable water, poverty and ignorance remain the key factors favouring the spread of the disease in the different communities. Also, administration of praziquantel to children varied among individual communities, which depends on the availability of health professionals and drugs for children who are usually left out in control programs[23]. Thus, the high prevalence of S. haematobium infection recorded in some of the communities in this study, particular in Enwan (45.0%), is due to a combination of the factors above. Findings herein is similar to previous report from the same community where a prevalence of 43.3% was recorded in 11–30 yr old individuals[12]. This is an indication that factors that promote the spread of the disease such as absence of portable water, poor sanitary habits, poverty, ignorance, fishing and swimming persists. However, observation herein of a significantly lower prevalence in Ikpeshi (20.0%), when compared with previous report by[18], who recorded 73.1% in children from the same community, is an indication that control efforts are on-going in the community. Nonetheless, there is still more to be done to ensure continuous decline in prevalence of the disease.


  Conclusion Top


S. haematobium is still endemic among school children in most of the communities in the study area despite the administration of drugs, which is majorly due to regular and continued contacts with parasite-infested water. Also, this effort is being hindered by lack of co-operation of community leaders and/or indigenes with health personnel, poor knowledge and inadequate sanitary and water facilities. Even after drug administration where available, inhabitants are left with no other option than to still depend on water from stream/river for their domestic needs as it “appears” to be the most hygienic. Therefore, in addition to drug administration, an integrated control approach involving the provision of sanitary toilets in homes and schools, regular portable water, snail control and mass sensitization should be put in place in each of the communities. Finally, to ensure that the goal of WHO in controlling NTDs is actualized by 2020, all stakeholders including the government, community leaders, teachers, parents and children should be co-opted in control programs to maximize its effectiveness.

Conflict of Interest: None


  Acknowledgements Top


The authors appreciate the support of the head of the department of Animal and Environmental Biology and Akoko-Edo local government health authority in securing ethical permits for the conduct of the research. We appreciate the staff of the various schools, local government health personnel, parents and pupils for their support in the conduct of the research.





 
  References Top

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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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