Background

Soil transmitted helminth (STH) infections is tagged as one of the most common and neglected infections at worldwide [1]. This disease is very rampant with humans living in areas of poverty in the developing world. About one billion individuals were reported to carry helminthic worms, in which most of them are living in low socio-economic settings, in sub-Saharan Africa [2, 3]. Studies have shown that children are the most vulnerable groups affected by helminths [4,5,6]. Epidemiological surveys have demonstrated that poor sanitary conditions such as defecation and fecal contamination of water bodies are the most important factors leading to intestinal worm infestation [7] while the spread is due to personal hygiene [8]. Nigeria, is endemic for helminth infections, in which ascariasis, trichuriasis, and hookworm were incriminated as the major cause, with estimated cases of 55 million, 34 million, and 38 million, respectively [9, 10].

Both pre-school and school age children (0–15 years) are the groups at risk of getting infected [4,5,6]. The effects of helminthic infection in children are very detrimental. Furthermore, chronic infection is highly associated with malabsorption, inflammation, reduced immunity etc., leading to long-term morbidity such as growth retardation [11], impaired cognition/school performance, [12] etc. This vicious cycle is most detrimental in early childhood when the child is most dependent on nutritional resources for its physical and mental development.

Major interventions (in terms of treatment and/or preventive chemotherapy) that were put in place to curb the menace of helminth infections in Nigeria had basically catered for school aged children [13] and sometimes adults. This implies that pre-school aged (0–4 years) children were left out leaving them at the mercies of their parents who may not be able to afford proper health care for affected child especially in the rural communities.

In view of the general neglect of this age group in helminth control strategies, it is important to provide evidences to justify more integrative control approaches. However, most studies focused more on school aged children with few reports on pre-school-aged children [4, 14,15,16]. With this background, this study therefore seeks to determine the prevalence of STH among children less than 2 years in an urban and rural area of Ogun State.

Methods

Study area

This study was carried out in a purposively selected rural and urban communities “Olugbo and Obantoko, respectively” located Odeda Local Government Area of Ogun state, Nigeria. The inhabitants of the urban areas primarily depend on boreholes for water resource and dug wells as supplement, with good toilet facilities. On the other hand, the inhabitants of the rural communities primarily depend on streams for water resource, poor toilet facility. Hygiene and sanitation practices and waste disposal facilities are inappropriate in the rural area.

Study participants

Community members of the selected area were sensitized about the research through the assistance of Primary Health Care (PHC) center staffs and the Community Development Association (CDA) leaders. A total sampling of households within the community was done and consenting parents with children belonging to age category 0–2 years were recruited into the study. Parents of children who could provide adequate stool specimen at the point of visit were asked to converge at the PHC center where samples were collected and questionnaires were administered.

Questionnaire administration

Parents/caregivers whose children could provide adequate stool specimen were interviewed using a structured questionnaire at the PHC centre. Age and sex of each child, household sanitary, and personal hygiene conditions were documented using the questionnaire.

Laboratory procedure

One gram of the stool sample collected from each pre-schooler was prepared using sodium-acetate-acetic acid-formalin (SAF) ether concentration technique to increase the sensitivity of STH ova detection [17]. Samples were emulsified in 10 mL of SAF solution and transported in ice packs to the parasitology laboratory, for analysis within 2 h of collection. In the laboratory, sample bottles were vigorously agitated to efficiently suspend the stool in the solution. Stool suspension was further strained through a 13-mm sieve into a centrifuge tube, and the filtrate was centrifuged at 2000 rpm for 5 min. The resulting supernatant was discarded; then 7 mL of normal saline and 3 mL of petroleum ether were added to the sediment. The resulting mixture was shaken vigorously and centrifuged for 5 min at 2000 rpm. The first three layers of the suspension observed after centrifuging were discarded leaving the last layer of sediment. Sediment was pipette onto clean, oil-free glass slide and examined for the ova of gastrointestinal helminths under × 10 objective lens [17].

Statistical data analysis

All statistical analyses were performed using IBM SPSS 20.0 version, Armonk, NY, IBM Corp. Data obtained were first subjected to descriptive statistics including frequencies and cross-tabulations, followed by Pearson chi-square analysis to test for variables that were significantly associated with infection among the surveyed population. Probability values less than 0.05 were considered significant. Parasite species combinations and specific co-infection prevalence were illustrated using Venn diagrams.

Results

Demographic characteristics of the respondents

Only 103 children (50 urban, 53 rural) were able to provide amount of stool samples (1 g). Majority of the study participants 40 (38.8%) were within the age range of 0–6 months, which was followed by infants within the age range 19–24 months 25 (24.3%). The least proportion of the children 14 (13.6%) fell within the age range 13–18 months. Furthermore, slightly more females participated in the study compared to males (Table 1).

Table 1 Demographic characteristics of the pre-school aged children
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Prevalence of individual STHs among children aged 0–2 years from selected rural and urban communities

The overall prevalence of STH in this study was 69.9%. Three soi-transmitted helminths; Ascaris lumbricoides, Trichuris trichuria, and Hookworms were prevalent among the study population, with A. Lumbricoides recording the highest prevalence (68.0%). This was followed by hookworm (49.5%) and T. Trichuria (18.5%) (Table 2). Furthermore, these infections were significantly more prevalent in the rural community compared to the urban community (Table 2).

Table 2 Prevalence of individual STHs among children aged 0–2 years from selected rural and urban communities
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Prevalence of STHs by age and sex among children 0–2 years from selected rural and urban communities

Generally, there was a significant difference in prevalence of STH from the two communities (p < 0.05), with 79.2% and 60.0% of the children from rural and urban community being positive for at least one of the three STHs, respectively (Table 3). However, the highest prevalence was observed to occur among children that fell between 19 and 24 months in both communities, while the least prevalence was found among children within the age range 0–6 months (Table 3). Furthermore, infection with A. lumbricoides and Hookworm was significantly higher among children aged 19–24 months while the least prevalence were recorded among children aged 0–6 months (Table 4).

Table 3 Prevalence of STHs by age and sex among children aged 0–2 years from selected rural and urban communities
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Table 4 Prevalence of STHs by age and gender across different parasite types
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More males were infected from both communities; however, this does not reach a statistically significant level [p > 0.05] (Table 3). Similarly, no significant parasite specific prevalence was recorded with respect to gender in the study population (Table 4).

Helminth parasite-specific combination prevalence in the study population

Generally, A. Lumbricoides was found to be more prevalent as a single infection from both communities with the highest occurrence from the urban community (Figs. 1 and 2). Most of the T. Trichuria and hookworm infections were either in co-infections or multiple infections as revealed in the venn diagram (Figs. 1 and 2). More so, only 1 case each of T. Trichuria and hookworm occurred as a single infection and was found in the urban community.

Fig. 1
figure 1

Parasite specific combination prevalence in the urban community

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Fig. 2
figure 2

Parasite specific combination prevalence in the rural community

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We observed that co-infection of A. Lumbricoides and Hookworm were more prevalent among the children from both communities. This was followed by multiple infections of the three helminths (Figs. 1 and 2). Futhermore, no co-infection existed between [A. lumbrociodes and T. trichuria] as well as [T. trichuria and hookworm] in this study (Figs. 1 and 2).

Hygiene, attitude, and practice of pre-schoolers from selected urban and rural communities

More of the respondents (parents) from rural community (54% compared with 33.9% from urban) use open pit. This is followed by 23(46.7%) that uses open defecation. However, majority of the parents/care givers from urban (49.1%) reported that they throw their children feces into water closet after using the potty, while about 17% uses open defecation (Table 5).

Table 5 Hygiene attitudes and practices of the surveyed preschool aged children (< 2 years)
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Furthermore, majority of the parents/caregivers from both urban and rural communities claimed they do not wash their children hands after defecation. In the same vein, about 64% of the mothers from urban and rural communities respectively do not wash their hands before feeding their children (Table 5).

A high proportion (81.1%) of the children from urban community does not wear sandals while playing, while only 8% of the children from rural communities wear sandal while playing (Table 5).

Discussion

It is imperative to constantly evaluate the prevalence of intestinal helminths among children owing to the ill-effects posed by these parasites among the vulnerable groups.

This study revealed a very high infection levels already in this age group and a clear exposure time relationship with more infections in older ages. A rural-urban difference occurred in terms of prevalence, with similar prevalence by sex.

The high prevalence recorded for A. lumbricoides (69.9%) and hookworm (49.5%) is a pointer to showcase the vulnerability of the children less than 2 years to intestinal helminths, and this justifies the need to include them in deworming programs.

Just as it occurs in several studies from Nigeria [18,19,20], A. lumbricoides was found to be more prevalent, followed by Hookworm and T. trichuria, respectively. However, some studies reported higher prevalence of hookworm [15, 21]. The difference observed could be attributed to low socio-economic status especially among the rural communities. Studies have demonstrated an inverse relationship between socio-economic status and prevalence of A. lumbricoides [16]. The low socio-economic status (e.g., lack of toilet facilities and being unable to afford sandal for their children) as well as poor hygiene practices demonstrated by the rural participants from the rural community used in this study could explain why significantly high proportion of the respondents were infected with A. lumbricodes and Hookworm compared with their urban counterparts.

The fact that there was no significant difference in STH prevalence between girls and boys is likely to be related with the age group. In this age group, the children do not yet show major differences in activities they seek by own motivation and that exposes them [22]. They still largely depend on caretakers who provide them food and water and clean them. This picture changes when it comes to school-aged children, where boys mostly show higher infection levels than girls owing to more risky outdoor and hygiene behavior.

Nevertheless, a high proportion of the children between ages 19 and 24 months were positive to helminth infection compared with other age brackets. It is important to note that at that age, most children would have been walking actively, and studies have shown that children are more likely to walk barefooted [23], hereby exposing them to hook worm infections. Apart from this, studies have showed that in developing countries, young children crawl and play in areas where they may come into contact with soil that is contaminated with human and animal feces [24]. All this factors linked with the poor standard of living and a hygiene practice predisposes these young children to STHs and this poses a serious threat on their growth and development.

On the other hand the primary food and fluid for children ≤1 year is breast milk and are not able to crawl to areas where they could come in contact with parasites. This explains the low prevalence observed among the younger babies.

Poly-parasitism or multiple infections were high for “Ascaris + Hookworm” from both communities (being more prevalent in rural community) and followed by the combination of the three STHs. Common predisposing factors that could link all of them together is low standard of living and poor hygiene practices [16].

To reduce or stop the transmission of STHs, there is need to break the transmission cycle; however, this study showed that the current living standard coupled with poor hygiene practices among the study population is rather strengthening the cycle instead of breaking it.

Conclusion

STHs are prevalent among the study population, hence some considerations should be given to children under two with respect to deworming programs. This can be through production of less stronger drugs than can be administered to them during mass deworming programmes.