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Table 1 Soil-transmitted helminth prevalence (%) with 95% CI in school-age children in 2008 and in 2016 in Sierra Leone

From: Soil-transmitted helminth infection in school age children in Sierra Leone after a decade of preventive chemotherapy interventions

  Prevalence in 2008* (95% CI) Prevalence in 2016 (95% CI) Reduction compared to 2008 (%)
n Ascaris lumbricoides Trichuris trichiura Hookworm Any STH n A. lumbricoides T. trichiura Hookworm Any STH Hookworm Any STH
Overall 2777 6.6 (0–25) 1.8 (0–30.2) 38.5 (5.4–95.1) 48.3(5.4–96.3) 3632 4.4 (3.7–5.1)a 0.7 (0.5–1.1)a 14.9 (13.8–16.1) a 18.3 (17.0–19.5) a 48.3% 63.1%
By District
 Bo 163 2.0 (0–11.8) 1.11 (0–3.6) 12.9 (5.4–71.4) 18.4 (5.4–71.4) 294 0.0 (0.0–1.3) 0.3 (0.1–1.9) 8.2 (5.6–11.9) 8.2 (5.6–11.9) 59.4% 67.5%
 Bombali 215 8.6 (6.0–12.5) 0 (0–1.2) 17.9 (13.3–29.7) 25.2(18.1–40.5) 244 3.7 (2.0–6.9) 2.9 (1.4–5.8) 25.8 (20.7–31.7) 28.3 (23.0–34.2) −42.5% −4.8%
 Bonthe 196 1.0 (0–19.0) 13.7 (10.3–18.2) 56.5 (28.1–70.9) 62.7 (28.1–80.0) 251 2.8 (1.4–5.6) 1.2 (0.4–3.5) 33.1 (27.5–39.1) 34.7 (29.0–40.7) 41.0% 54.3%
 Kailahun 187 0.0 x(0.0–0.0) 0 (0–2.2) 49.8 (32.6–52.6) 49.8 (34.8–52.6) 298 3.4 (1.8–6.1) 0.7 (0.2–2.4) 9.7 (6.9–13.6) 12.4 (9.1–16.6) 79.1% 73.7%
 Kambia 223 13.6 (8.2–21.3) 0 (0–6.7) 22.5 (16.3–26.7) 35.8 24.5–48.3) 250 8.8 (5.9–13.0) 0.0 (0.0–1.5) 1.2 (0.4–3.5) 10.0 (6.9–14.3) 94.5% 73.5%
 Kenema 208 0 (0–6.1) 1.8 (0–3.3) 53.3 (41.5–66.7) 55.3 (41.5–69.7) 301 0.3 (0.1–1.9) 0.3 (0.1–1.9) 6.0 (3.8–9.3) 6.6 (4.3–10.0) 88.5% 88.1%
 Koinadugu 272 3.0 (0–8.6) 0 (0–3.0) 64.8 (53.7–95.1) 68.5(56.7–96.3) 300 7.7 (5.2–11.2) 0.0 (0.0–1.3) 14.0 (10.5–18.4) 20.0 (15.9–24.9) 80.9% 74.5%
 Kono 244 4.8 (3.2–6.9) 0 (0–1.6) 13.7 (8.1–15.5) 18.5 (11.3–20.7) 242 5.8 (3.5–9.5) 1.7 (0.6–4.2) 12.8 (9.2–17.6) 17.4 (13.1–22.6) −0.8% 3.3%
 Moyamba 217 9.8 (6.6–12.7) 15.0 (3.4–30.2) 60.7 (42.6–70.9) 72.3 (45.9–80) 252 5.2 (3.0–8.6) 0.8 (0.2–2.8) 23.8 (19.0–29.4) 27.4 (22.2–33.2) 59.0% 66.8%
 Port Loko 173 11.0 (1.7–25) 0.9 (0–3.1) 46.4 (38.5–51.7) 53.3(50–56.1) 249 8.0 (5.3–12.1) 0.0 (0.0–1.5) 4.4 (2.5–7.7) 11.2 (7.9–15.8) 90.7% 81.0%
 Pujehun 198 13.4 (5.1–21.8) 3.5 (0–5.5) 42.7 (8.5–75.9) 53.6 (15.3–75.9) 252 6.3 (3.9–10.1) 0.4 (0.1–2.2) 18.7 (14.3–23.9) 21.8 (17.2–27.3) 50.0% 60.4%
 Tonkolili 280 7.0 (6.7–14.6) 2.2 (1.3–10) 24.7 (17.1–35.4) 3.3 (30–50) 301 4.3 (2.5–7.2) 1.3 (0.5–3.4) 31.2 (26.3–36.7) 33.2 (28.1–38.7) −26.8% 9.8%
 WA-R 201 9.3 (4.5–13.2) 5.6 (3.6–8.4) 28.5 (25–44.7) 41.7 (31.8–60.5) 201 0.5 (0.1–2.8) 0.5 (0.1–2.8) 13.9 (9.8–19.4) 13.9 (9.8–19.4) 54.9% 70.0%
 WA-U 197 4.6 (2.4–8.5) 0.5 (0.1–2.8) 4.6 (2.4–8.5) 9.6 (6.3–14.6)
By Sex
 Male 1411      1844 4.1 (3.3–5.1) 1.0 (0.6–1.5) 18.8 (17.1–20.7)b 21.5 (19.7–23.4)b
 Female 1366      1788 4.6 (3.8–5.7) 0.5 (0.3–1.0) 10.9 (9.5–12.4) 14.9 (13.4–16.7)
By prevalence level
 Low 282 3.5 (1.9–6.4) 1.1 (0.4–3.1) 9.2 (6.4–13.2) 13.8 (10.3–18.3) 2092 2.0 (1.5–2.7) 0.3 (0.1–0.6)c 6.0 (5.0–7.1)d 8.3 (7.2–9.5) 34.8% 39.9%
 Moderate 1095 7.1 (5.7–8.8) 2.6 (1.9–3.8) 23.1 (20.7–25.7) 32.9 (30.2–35.7) 1241 4.7 (3.6–6.0) 1.0 (0.6–1.8)d 23.4 (21.2–25.9)d 29.2 (26.7–31.8) −1.3% 11.2%
 High 1400 8.0 (6.7–9.5) 5.4 (4.4–6.7) 56.4 (53.7–58.9) 69.8 (67.3–72.1) 299 9.0 (6.3–12.8) 2.7 (1.4–5.2)c 42.1 (36.7–47.8)c 53.8 (48.2–59.4) 25.4% 22.9%
By Sites
 Sentinel 1305 3.9 (3.0–5.1) 0.5 (0.3–1.1) 13.3 (11.6–15.3)e 16.5 (14.6–18.6)e
 Non- Sentinel 2327 4.6 (3.8–5.5) 0.9 (0.6–1.3) 15.8 (14.4–17.4) 19.3 (17.7–20.9)
  1. * Data for prevalence of STH in 2008 are available in Koroma et al. [32] in which WA-R and WA-U were grouped into Western Area
  2. a Significantly reduced prevalence between 2008 versus 2016 (P < 0.001)
  3. b Significantly higher prevalence in males versus females in 2016 (P = 0.001)
  4. c No significant difference between baseline versus impact (P > 0.05)
  5. d Significantly reduced between baseline versus impact (P < 0.05)
  6. e No significant difference between sentinel and non-sentinel sites (P > 0.05)
  7. CI: Confidence interval; STH: Soil-transmitted helminth; WA-U: Western Area Urban; WA-R: Western Area Rural