The average S. mansoni prevalence in the four PHS was 11.0% (95% CI: 6.4–15.5), while it was 6.6% (95% CI: 1.4–11.8%) in the two low-prevalence schools. The highest S. mansoni infection prevalence was found in Ziondrou (22.7%, 95% CI: 11.5–37.8%). The arithmetic mean egg count among S. mansoni-positive individuals was 123.8 EPG in four PHS schools and 18.7 EPG in the two low-prevalence schools. S. mansoni prevalence was significantly different between schools (χ2 = 14.3, P = 0.014). Infections with S. mansoni were mainly light (80.8%), while moderate (15.4%) and heavy (3.9%) infections were less common. The logistic regression analysis showed that the prevalence of S. mansoni was significantly lower in households with latrine (odds ratio (OR) = 0.37, 95% CI = 0.16–0.89). The two age groups did not differ significantly in the S. mansoni prevalence (χ2 = 0.100, P = 0.751).
The average S. haematobium prevalence was 3.3% (95% CI: 0.7–5.9%) in the four PHS schools and 1.1% (95% CI: -1.1-3.3%) in the two low-prevalence schools. The highest prevalence of S. haematobium was found in Zoukougbeu (8.2%, 95% CI: 0.2–16.1%). Among S. haematobium-positive children, the intensity of the infection was 16.7 eggs/10 ml of urine (95% CI: 0.3–33.0 eggs/10 ml of urine) and 37.0 eggs/10 ml of urine (95% CI: 37.0–37.0 eggs/10 ml of urine) in PHS and low-prevalence schools, respectively. PHS and low-prevalence schools differed significantly in the S. haematobium intensity of infection. All the infections with S. haematobium were of light intensity (< 50 eggs/10 ml of urine). S. haematobium prevalence differed significantly between the two age groups with children aged 11–12 years at higher odds of infection (χ2 = 11.0, P = 0.001).
Demographic Characteristics
Table 3 summarises the demographic characteristics of the study villages, including results from the questionnaire survey regarding the last round of preventive chemotherapy. Overall, 274 children had complete parasitological and questionnaire data. There were 150 (54.7%) boys. There was no significant sex difference between the two groups of schools. With regard to age, 60.6% of the children were in the younger age group (9–10 years). There was no significant difference in the age groups between the PHS and low-prevalence schools.
Table 3
Characteristics of study population in six selected schools from a large SCORE study in western Côte d’Ivoire in November 2016
| | | Overall | | Persistent hot-spot schools | | Low-prevalence schools |
Variable | | | | | Gbadrou | | Mona | | | Ziondrou | | Zoukougbeu | Tobly Bangolo | | Zê | |
| | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) |
Sex | | | | | | | | | | | | | | | | | | | | | | |
| Girl | | 124 | 45.3 | | 12 | 27.3 | | 20 | 43.5 | 23 | 52.3 | | 28 | 57.1 | | 18 | 39.1 | | 23 | 51.1 |
| Boys | | 150 | 54.7 | | 32 | 72.7 | | 26 | 56.5 | 21 | 47.7 | | 21 | 42.9 | | 28 | 60.9 | | 22 | 48.9 |
Age | | | | | | | | | | | | | | | | | | | | | | |
| Age group 1 (9–10 years) | 166 | 60.6 | | 29 | 65.9 | | 31 | 67.4 | 19 | 43.2 | | 30 | 61.2 | | 35 | 76.1 | | 22 | 48.9 |
| Age group 1 (11–12 years) | 108 | 39.4 | | 15 | 34.1 | | 15 | 32.6 | 25 | 56.8 | | 19 | 38.8 | | 11 | 23.9 | | 23 | 51.1 |
Mean number of person in houses | 8.3 | | | 8.7 | | | 7.2 | | | 8.8 | | | 8.5 | | | 7.9 | | | 8.7 | |
Present at MDA | Yes | | 267 | 97.5 | | 44 | 100.0 | | 45 | 97.8 | 44 | 100.0 | | 47 | 96.0 | | 43 | 93.5 | | 44 | 97.8 |
| No | | 6 | 2.2 | | 0 | 0.0 | | 1 | 2.2 | | 0 | 0.0 | | 1 | 2.0 | | 3 | 6.5 | | 1 | 2.2 |
| Don't remember | 1 | 0.3 | | 0 | 0.0 | | 0 | 0.0 | | 0 | 0.0 | | 1 | 2.0 | | 0 | 0.0 | | 0 | 0.0 |
Received PZQ | | | | | | | | | | | | | | | | | | | | | |
| Yes | | 261 | 95.3 | | 43 | 97.7 | | 44 | 95.6 | 44 | 100.0 | | 49 | 100.0 | | 37 | 80.4 | | 44 | 97.8 |
| No | | 13 | 4.7 | | 1 | 2.3 | | 2 | 4.4 | | 0 | 0.0 | | 0 | 0.0 | | 9 | 19.6 | | 1 | 2.2 |
Received and took all praziquantel together | | | | | | | | | | | | | | | | | | | |
| Yes | | 256 | 93.4 | | 42 | 95.5 | | 41 | 89.1 | 44 | 100.0 | | 49 | 100.0 | | 36 | 78.3 | | 44 | 97.8 |
| No or don't know | 18 | 6.6 | | 2 | 4.5 | | 5 | 10.9 | 0 | 0.0 | | 0 | 0.0 | | 10 | 21.7 | | 1 | 2.2 |
Don't know what PZQ treats | | | | | | | | | | | | | | | | | | | | |
| Yes | | 179 | 65.3 | | 34 | 77.3 | | 23 | 50.0 | 23 | 52.3 | | 38 | 77.5 | | 38 | 82.6 | | 23 | 51.1 |
| No | | 95 | 34.7 | | 10 | 22.7 | | 23 | 50.0 | 21 | 47.7 | | 11 | 22.5 | | 8 | 17.4 | | 22 | 48.9 |
Most of the children (97.5%) declared that they were present during the last treatment round and 95.3% of them had received praziquantel. We found a statistical significant difference between PHS and low-prevalence schools in praziquantel coverage, a higher coverage was reported in PHS schools (X2 = 11.8, p = 0.001). In Ziondrou and Zoukougbeu, all the surveyed children said that they received and took the drugs, while in the remaining schools some children did not take the drugs. Two-third of the children (65.3%) did not know which disease praziquantel cured.
Socio-economic Status And Wash Indicators
Figure 1 displays the characteristics of household materials in the study villages. Most of children in Zoukougbeu lived in houses with walls made of bricks, stones or cement (91.8%) and floors done with cement, tiles or linoleum (93.9%). The majority of children’s families had houses covered by metal roofs (91.8%) (Table 4). In Mona, houses were predominantly constructed with simple or natural materials for wall (52.2%) and roof (63.0%). Three-quarter of children’s families in the study villages had electricity at home. In Tobly Bangolo, only half of the participants had access to the power grid. Mobile phones were available in the households of all children surveyed in Zoukougbeu and Zê.
Table 4
Economic characteristics of households in six selected schools from a large SCORE study in western Côte d’Ivoire in November 2016
Variable | | | Overall | | Persistent hot-spot schools | | Low-prevalence schools |
| | | | | | Gbadrou | | Mona | | Ziondrou | | Zoukougbeu | | Tobly Bangolo | | Zê |
| | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) |
Wall material | Brick, stones or cement | 213 | 77.5 | | 33 | 75 | | 22 | 47.8 | | 36 | 81.8 | | 45 | 91.8 | | 36 | 78.3 | | 41 | 91.1 |
| Other | | 62 | 22.6 | | 11 | 25 | | 24 | 52.2 | | 8 | 18.2 | | 4 | 8.2 | | 10 | 21.7 | | 4 | 8.9 |
Floor material | Cement, tiles, linoleum | 227 | 82.9 | | 39 | 88.6 | | 26 | 56.5 | | 40 | 90.9 | | 46 | 93.9 | | 39 | 84.8 | | 37 | 82.2 |
| Other | | 47 | 17.2 | | 5 | 11.7 | | 20 | 43.5 | | 4 | 9.1 | | 3 | 6.1 | | 7 | 15.2 | | 8 | 17.8 |
Roof material | Metal cover | 213 | 77.7 | | 36 | 81.8 | | 17 | 37 | | 41 | 93.8 | | 45 | 91.8 | | 33 | 71.7 | | 41 | 91.1 |
| Other | | 61 | 22.3 | | 8 | 18.9 | | 29 | 63 | | 3 | 6.2 | | 4 | 8.2 | | 13 | 28.3 | | 4 | 8.9 |
Electricity | Yes | | 205 | 74.8 | | 34 | 77.3 | | 28 | 60.8 | | 37 | 84.1 | | 43 | 87.7 | | 23 | 50 | | 40 | 88.9 |
| No | | 69 | 25.2 | | 10 | 22.7 | | 18 | 39.2 | | 7 | 15.9 | | 6 | 12.3 | | 23 | 50 | | 5 | 11.1 |
Mobile phone | Yes | | 261 | 95.3 | | 42 | 95.5 | | 41 | 89.1 | | 43 | 97.7 | | 49 | 100 | | 41 | 89.1 | | 45 | 100 |
| No | | 13 | 4.7 | | 2 | 4.5 | | 5 | 10.9 | | 1 | 2.3 | | 0 | 0 | | 5 | 10.9 | | 0 | 0 |
Table 5 summarises WASH indicators in the study area. There were three types of public water sources: wells, pumps and taps. In PHS schools, between 30 and 38 children per school (65.2–86.4%) mentioned that their parents collected water from safe water sources. The proportions of children who reported that their parents obtained water from safe water sources were 86.4%, 72.7%, 65.3% and 65.2% in Gbadrou, Ziondrou, Zoukougbeu, Mona, respectively. In Ziondrou (65.9%) and Gbadrou (52.3%) safe water was predominantly collected from taps. In Zoukougbeu (30.6%) and Mona (28.3%), wells were common.
Table 5
WASH indicators in six study schools from a large SCORE study in western Côte d’Ivoire in November 2016
Variable | | | Overall | | | Persistent hot-spot schools | Low-prevalence schools |
| | | | | | Gbadrou | | | Mona | | | Ziondrou | | | Zoukougbeu | | Tobly Bangolo | | Zê | |
| | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) |
Protected well | Yes | | 67 | 24.5 | | 8 | 18.2 | | 13 | 28.3 | | 1 | 2.3 | | 15 | 30.6 | | 18 | 39.1 | | 12 | 26.7 |
| No | | 207 | 75.5 | | 36 | 81.8 | | 33 | 71.7 | | 43 | 97.7 | | 34 | 69.4 | | 28 | 60.9 | | 33 | 73.3 |
Tap water | Yes | | 93 | 33.9 | | 23 | 52.3 | | 5 | 10.9 | | 29 | 65.9 | | 13 | 26.5 | | 4 | 8.7 | | 19 | 42.2 |
| No | | 181 | 66.1 | | 21 | 47.7 | | 41 | 89.1 | | 15 | 34.1 | | 36 | 73.5 | | 42 | 91.3 | | 26 | 57.8 |
Public pumps | Yes | | 42 | 15.3 | | 7 | 15.9 | | 12 | 26.1 | | 2 | 4.5 | | 4 | 8.2 | | 11 | 23.9 | | 6 | 13.3 |
| No | | 232 | 84.7 | | 37 | 84.1 | | 34 | 73.9 | | 42 | 95.5 | | 45 | 91.8 | | 35 | 76.1 | | 39 | 86.7 |
Safe water sources | Yes | | 202 | 73.7 | | 38 | 86.4 | | 30 | 65.2 | | 32 | 72.7 | | 32 | 65.3 | | 33 | 71.7 | | 37 | 82.2 |
| No | | 72 | 26.3 | | 6 | 13.6 | | 16 | 34.8 | | 12 | 27.3 | | 17 | 34.7 | | 13 | 28.3 | | 8 | 17.8 |
Latrine at home | Yes | | 203 | 74.1 | | 27 | 61.4 | | 32 | 69.6 | | 29 | 65.9 | | 44 | 89.8 | | 35 | 76.1 | | 36 | 80.0 |
| No | | 71 | 25.9 | | 17 | 38.6 | | 14 | 30.4 | | 15 | 34.1 | | 5 | 10.2 | | 11 | 23.9 | | 9 | 20.0 |
Latrine at school | Yes | | 140 | 51.1 | | 2 | 4.5 | | 35 | 76.1 | | 36 | 81.8 | | 17 | 34.7 | | 9 | 19.6 | | 41 | 91.1 |
| No | | 134 | 48.9 | | 42 | 95.5 | | 11 | 23.9 | | 8 | 18.2 | | 32 | 65.3 | | 37 | 80.4 | | 4 | 9.0 |
Latrine | Yes | | 238 | 86.9 | | 28 | 63.6 | | 40 | 87 | | 44 | 100 | | 45 | 91.8 | | 36 | 78.3 | | 45 | 100 |
| No | | 36 | 13.1 | | 16 | 36.4 | | 6 | 13 | | 0 | 0 | | 4 | 8.2 | | 10 | 21.7 | | 0 | 0.0 |
Open defecation | Yes | | 111 | 40.5 | | 40 | 90.9 | | 9 | 19.6 | | 3 | 6.8 | | 20 | 40.8 | | 35 | 76.1 | | 4 | 8.9 |
| No | | 163 | 59.5 | | 4 | 9.9 | | 37 | 80.4 | | 41 | 93.2 | | 29 | 59.2 | | 11 | 23.9 | | 41 | 91.1 |
In low-prevalence schools, the number of children who reported that they used safe water sources was 37 (82.2%) and 33 (71.7%) in Zê and Tobly Bangolo, respectively. In Zê, water was mainly collected from taps (42.2%), while in Tobly Bangolo, wells were the predominant source (39.1%). The proportion of children who said that their parents collected water from safe sources was 72.1% in PHS schools and 76.9% in low-prevalence schools with no statistically significant difference (X2 = 0.72, p = 0.396).
Three-quarter of the children (74.1%) had latrines at home, while approximately half of the children (48.9%) had no latrine at school. In PHS, latrines were available in more than 80% of children’s houses. A high coverage of latrines at school was mainly recorded in Ziondrou (81.8%). In one of the low-prevalence schools, Zê, high coverage of latrines at home (80.0%) and school (91.1%) was reported.
Figure 2 shows latrine availability and open defecation practice, stratified by village. Open defecation was practiced in each of the six villages studied in greater depth. In general, open defecation was less practiced in villages with high number of latrines. In PHS, less than half of the children (43.2%) from Gbadrou claimed that they never used a latrine. Most of the children in Gbadrou (95.5%), and Zoukougbeu (65.3%) did not use latrines at school. Open defecation was widely practiced in Gbadrou (90.9%).
In low-prevalence schools, the number of children who had latrines (n = 36) and those practicing open defecation (n = 35) were similar in Tobly Bangolo. Most of the children (80.4%) in the later school did not use latrine at school when needed to defecate at school. Open defecation was commonly practiced in Tobly Bangolo (76.1%).
Water-related Activities
Table 6 summarises the water sources for playing, laundry, bathing and collecting water for domestic or agricultural use in the study area. Most of the children (61.7%) reported that they performed the aforementioned activities in lake, pond or stream water.
Table 6
Water-related activities in the six schools of a large SCORE study in western Côte d’Ivoire in November 2016
Variable | | | Overall | | | Persistent hot-spot schools | | | Low-prevalence schools |
| | | | | | Gbadrou | | | Mona | | | Ziondrou | | | Zoukougbeu | | Tobly Bangolo | Zê | |
| | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | p-value |
Do you ever do the following activities* in a lake, pond, or stream? | Yes | | 169 | 61.7 | | 35 | 79.6 | | 23 | 50 | | 32 | 72.7 | | 22 | 44.9 | | 21 | 45.6 | | 36 | 80 | |
| No | | 105 | 38.3 | | 9 | 20.4 | | 23 | 50 | | 12 | 27.3 | | 27 | 55.1 | | 25 | 54.4 | | 9 | 20 | 0.028 |
Have you, in the past month, done any of the following activities* in a lake, pond or stream? | Yes | | 138 | 50.4 | | 30 | 68.2 | | 17 | 36.9 | | 27 | 61.4 | | 14 | 28.6 | | 17 | 36.9 | | 33 | 73.3 | |
| No | | 136 | 49.6 | | 14 | 31.8 | | 29 | 63.1 | | 17 | 38.4 | | 35 | 71.4 | | 29 | 63.1 | | 12 | 26.7 | 0.402 |
Do you play in dam? | Yes | | 5 | 1.8 | | 0 | 0 | | 0 | 0 | | 0 | 0 | | 1 | 2 | | 4 | 8.7 | | 0 | 0 | |
| No | | 269 | 98.2 | | 44 | 100 | | 46 | 100 | | 44 | 100 | | 48 | 98 | | 42 | 91.3 | | 45 | 100 | 0.025 |
Do you play in pond? | Yes | | 7 | 2.5 | | 2 | 4.5 | | 0 | 0 | | 5 | 11.4 | | 0 | 0 | | 0 | 0 | | 0 | 0 | |
| No | | 267 | 97.5 | | 42 | 95.5 | | 46 | 100 | | 39 | 88.6 | | 49 | 100 | | 46 | 100 | | 45 | 100 | 0.059 |
Do you play in backwater? | Yes | | 21 | 7.7 | | 4 | 9.1 | | 3 | 6.5 | | 9 | 20.5 | | 1 | 2 | | 3 | 6.5 | | 1 | 97.8 | |
| No | | 253 | 92.3 | | 40 | 90.9 | | 43 | 93.5 | | 35 | 79.5 | | 48 | 98 | | 43 | 93.5 | | 44 | 2.3 | 0.152 |
Do you play in river? | Yes | | 94 | 34.3 | | 23 | 52.3 | | 10 | 21.7 | | 9 | 20.5 | | 10 | 79.6 | | 11 | 23.9 | | 31 | 68.9 | |
| No | | 180 | 65.7 | | 21 | 47.7 | | 36 | 78.3 | | 35 | 79.5 | | 39 | 20.4 | | 35 | 76.1 | | 14 | 31.1 | 0.004 |
Do you do the laundry in dam? | Yes | | 5 | 1.8 | | 0 | 0 | | 0 | 0 | | 0 | 0 | | 1 | 98 | | 4 | 8.7 | | 0 | 0 | |
| No | | 269 | 98.2 | | 44 | 100 | | 46 | 100 | | 44 | 100 | | 48 | 2 | | 42 | 91.3 | | 45 | 100 | 0.025 |
Do you do the laundry in pond? | Yes | | 7 | 2.6 | | 2 | 4.5 | | 0 | 0 | | 5 | 11.4 | | 0 | 0 | | 0 | 0 | | 0 | 0 | |
| No | | 267 | 97.4 | | 42 | 95.5 | | 46 | 100 | | 39 | 88.6 | | 49 | 100 | | 46 | 100 | | 45 | 100 | 0.059 |
*Activities: to do the laundry, play, bathe and collect water for domestic or agriculture use. |
Variable | | Overall | | Persistent hot-spot schools | | Low-prevalence schools | |
| | | | | Gbadrou | | Mona | | Ziondrou | | Zoukougbeu | | Tobly Bangolo | | Zê | p-value |
| | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | |
Laundry in backwater | Yes | 25 | 9.2 | | 5 | 11.4 | | 2 | 4.4 | | 12 | 27.3 | | 0 | 0 | | 4 | 8.7 | | 2 | 4.4 | 0.305 |
| No | 249 | 90.8 | | 39 | 88.6 | | 44 | 95.6 | | 32 | 72.7 | | 49 | 100 | | 42 | 91.3 | | 43 | 95.6 | |
Laundry in River | Yes | 97 | 35.4 | | 27 | 61.4 | | 14 | 69.6 | | 9 | 20.5 | | 11 | 22.5 | | 4 | 8.7 | | 32 | 71.1 | 0.310 |
| No | 177 | 64.6 | | 17 | 38.6 | | 32 | 30.4 | | 35 | 79.5 | | 38 | 77.5 | | 42 | 91.3 | | 13 | 28.9 | |
Bathe in lake | Yes | 3 | 1.1 | | 0 | 0 | | 0 | 0 | | 0 | 0 | | 1 | 2 | | 2 | 4.4 | | 0 | 0 | 0.216 |
| No | 271 | 98.9 | | 44 | 100 | | 46 | 100 | | 44 | 100 | | 48 | 98 | | 44 | 95.6 | | 45 | 100 | |
Bathe in pond | Yes | 6 | 2.2 | | 2 | 4.5 | | 0 | 0 | | 4 | 9.1 | | 0 | 0 | | 0 | 0 | | 0 | 0 | 0.081 |
| No | 268 | 97.8 | | 42 | 95.5 | | 46 | 100 | | 40 | 90.9 | | 49 | 100 | | 46 | 100 | | 45 | 100 | |
Bathe in backwater | Yes | 16 | 5.8 | | 2 | 4.5 | | 1 | 2.2 | | 11 | 25 | | 1 | 2 | | 1 | 2.2 | | 0 | 0 | 0.018 |
| No | 258 | 94.2 | | 42 | 95.5 | | 45 | 97.8 | | 33 | 75 | | 48 | 98 | | 45 | 97.8 | | 45 | 100 | |
Bathe in river | Yes | 69 | 25.2 | | 20 | 45.5 | | 7 | 15.2 | | 9 | 20.5 | | 8 | 16.3 | | 3 | 6.5 | | 22 | 48.9 | 0.538 |
| No | 205 | 74.8 | | 24 | 54.5 | | 39 | 84.8 | | 35 | 79.5 | | 41 | 83.7 | | 43 | 93.5 | | 23 | 51.1 | |
Collect water from lake or dam | Yes | 3 | 1.1 | | 0 | 0 | | 0 | 0 | | 0 | 0 | | 1 | 2 | | 2 | 4.4 | | 0 | 0 | 0.212 |
| No | 270 | 98.9 | | 44 | 100 | | 46 | 100 | | 44 | 100 | | 48 | 97.9 | | 44 | 95.6 | | 44 | 100 | |
Collect water from pond | Yes | 5 | 1.8 | | 3 | 6.8 | | 0 | 0 | | 2 | 4.5 | | 0 | 0 | | 0 | 0 | | 0 | 0 | 0.112 |
| No | 269 | 98.2 | | 41 | 93.2 | | 46 | 100 | | 42 | 95.5 | | 49 | 100 | | 46 | 100 | | 45 | 100 | |
Variable | | Overall | | Persistent hot-spot schools | | Low-prevalence schools | |
| | | | | Gbadrou | | Mona | | Ziondrou | | Zoukougbeu | | Tobly Bangolo | | Zê | p-value |
| | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | | n | (%) | |
Laundry in backwater | Yes | 25 | 9.2 | | 5 | 11.4 | | 2 | 4.4 | | 12 | 27.3 | | 0 | 0 | | 4 | 8.7 | | 2 | 4.4 | 0.305 |
| No | 249 | 90.8 | | 39 | 88.6 | | 44 | 95.6 | | 32 | 72.7 | | 49 | 100 | | 42 | 91.3 | | 43 | 95.6 | |
Laundry in River | Yes | 97 | 35.4 | | 27 | 61.4 | | 14 | 69.6 | | 9 | 20.5 | | 11 | 22.5 | | 4 | 8.7 | | 32 | 71.1 | 0.310 |
| No | 177 | 64.6 | | 17 | 38.6 | | 32 | 30.4 | | 35 | 79.5 | | 38 | 77.5 | | 42 | 91.3 | | 13 | 28.9 | |
Bathe in lake | Yes | 3 | 1.1 | | 0 | 0 | | 0 | 0 | | 0 | 0 | | 1 | 2 | | 2 | 4.4 | | 0 | 0 | 0.216 |
| No | 271 | 98.9 | | 44 | 100 | | 46 | 100 | | 44 | 100 | | 48 | 98 | | 44 | 95.6 | | 45 | 100 | |
Bathe in pond | Yes | 6 | 2.2 | | 2 | 4.5 | | 0 | 0 | | 4 | 9.1 | | 0 | 0 | | 0 | 0 | | 0 | 0 | 0.081 |
| No | 268 | 97.8 | | 42 | 95.5 | | 46 | 100 | | 40 | 90.9 | | 49 | 100 | | 46 | 100 | | 45 | 100 | |
Bathe in backwater | Yes | 16 | 5.8 | | 2 | 4.5 | | 1 | 2.2 | | 11 | 25 | | 1 | 2 | | 1 | 2.2 | | 0 | 0 | 0.018 |
| No | 258 | 94.2 | | 42 | 95.5 | | 45 | 97.8 | | 33 | 75 | | 48 | 98 | | 45 | 97.8 | | 45 | 100 | |
Bathe in river | Yes | 69 | 25.2 | | 20 | 45.5 | | 7 | 15.2 | | 9 | 20.5 | | 8 | 16.3 | | 3 | 6.5 | | 22 | 48.9 | 0.538 |
| No | 205 | 74.8 | | 24 | 54.5 | | 39 | 84.8 | | 35 | 79.5 | | 41 | 83.7 | | 43 | 93.5 | | 23 | 51.1 | |
Collect water from lake or dam | Yes | 3 | 1.1 | | 0 | 0 | | 0 | 0 | | 0 | 0 | | 1 | 2 | | 2 | 4.4 | | 0 | 0 | 0.212 |
| No | 270 | 98.9 | | 44 | 100 | | 46 | 100 | | 44 | 100 | | 48 | 97.9 | | 44 | 95.6 | | 44 | 100 | |
Collect water from pond | Yes | 5 | 1.8 | | 3 | 6.8 | | 0 | 0 | | 2 | 4.5 | | 0 | 0 | | 0 | 0 | | 0 | 0 | 0.112 |
| No | 269 | 98.2 | | 41 | 93.2 | | 46 | 100 | | 42 | 95.5 | | 49 | 100 | | 46 | 100 | | 45 | 100 | |
According to the questionnaire survey, only 7.7% of the responders played in backwater, while in Zê almost all children (97.8%) played in this type of water. More than 60% of the children did not play in rivers, while more than half of the children did so in Zoukougbeu (79.6%) and Gbadrou (52.3%) in the PHS and Zê (68.9%) a low-prevalence school.
Most of the children did not do laundry in lakes or small dams, with the exception of children from Zoukougbeu. Most of the responders did not do laundry in a river, while the majority of children did so in Gbadrou (61.4%), Mona (69.6%) and Zê (71.1%). Only 25.2% of the children bathed in the river, but in Zê, half of the children did so (50.0%).
Significant differences between the four PHS and two low-prevalence schools were found for doing the laundry, playing, bathing and collecting water for domestic or agriculture use, playing in small dams, playing in river, doing the laundry in small dams, bathing in backwater, collecting water from backwater, collecting stagnant water for domestic or agricultural use and using stagnant water for bathing (p < 0.05). Borderline statistical significant differences were found for playing and doing laundry in pond (p = 0.059). In contrast, there were no significant differences for the remaining variables of water-related activities between the four PHS and the two low-prevalence schools.
Children bathing in stagnant water were at higher odds of S. mansoni infection compared with children not reporting this activity (OR = 4.5, 95% CI: 1.6–12.6) (Table 7). Children from PHS schools bathed in stagnant water more frequently compared to those from low-prevalence schools (χ2 = 5.1, p = 0.024).
Table 7
Association between demographical and environmental factors and S. mansoni prevalence
Variable | Odds ratio | p-value | 95%CI |
Age group 11–12 year old | 1.5 | 0.37 | 0.63–3.48 |
Latrine at home | 0.4 | 0.03 | 0.16–0.89 |
Bathe in stagnant water | 4.5 | 0.004 | 1.63–12.55 |
Results From The Malacological Survey
Table 8 summarises the results of a cross-sectional malacological survey carried out in the study area. Overall, 76 human-water contact sites were reported in the six villages. In PHS schools, the number of human-water contact sites ranged between 10 (Mona) and 19 (Gbadrou). In the two low-prevalence schools, 14 and 9 human-water contact sites were visited in Zê and Tobly Bangolo, respectively. Rivers were the most common human-water contact sites (n = 59). Rice paddies constituted another 20 human-water contact sites. The average pH was 6.2 (range: 5.0-7.1). The average total dissolved solids was 9.5 ppm (range: 4–51 ppm) and the average conductivity was 38.9 µS (range: 9-103 µS).
Table 8
Snail species in the six schools of a large SCORE study in western Côte d’Ivoire in December 2016
Village | Persistent hot-spot schools | | Low-prevalence schools | Total |
| Gbadrou | Mona | Ziondrou | Zoukougbeu | | Tobly Bangolo | Zê | |
No of human-water contact sites | 19 | 10 | 12 | 12 | | 9 | 14 | 76 |
Snail species | | | | | | | | |
Biomphalaria pfeifferi | 0 | 77 | 12 | 0 | | 3 | 0 | 92 |
Bulinus forskalii | 2 | 6 | 3 | 6 | | 4 | 4 | 25 |
Bulinus globosus | 0 | 6 | 0 | 7 | | 3 | 0 | 16 |
Bulinus truncatus | 0 | 0 | 0 | 0 | | 1 | 0 | 1 |
Ferrissia eburnensis | 0 | 0 | 0 | 0 | | 0 | 4 | 4 |
Gyraulus costulatus | 3 | 13 | 1 | 6 | | 0 | 0 | 23 |
Lanistes ovum | 0 | 0 | 0 | 4 | | 0 | 0 | 4 |
Lymnaea natalensis | 7 | 54 | 1 | 21 | | 20 | 0 | 103 |
Melanoïdes tuberculata | 0 | 333 | 0 | 67 | | 0 | 0 | 400 |
Pila africana | 0 | 5 | 0 | 0 | | 0 | 0 | 5 |
Physa acuta | 0 | 7 | 0 | 8 | | 0 | 0 | 15 |
A total of 688 snails belonging to nine genera were found; namely, Biomphalaria, Bulinus, Ferrissia, Gyraulus, Lanistes, Lymnaea, Melanoïdes, Pila and Physa. Melanoïdes tuberculata (400 specimens) was the most abundant snail species. With regard to potential schistosomiasis intermediate host snails, there were 92, 25, 16 and one specimens of Bi. pfeifferi, Bu. forskalii, Bu. globosus and Bu. truncatus, respectively. However, none of snails were shedding schistosome cercariae, while some snails were observed shedding xiphidio-cercariae.