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Table 3 Results of snail survey during 2005–2015 in sentinel sites

From: Surveillance-based evidence: elimination of schistosomiasis as a public health problem in the Peoples’ Republic of China

Surveillance phase

Year

No. area surveyed

(ha)

No. area with infested snails

(ha)

No. area of new snail habitat(ha)

No. area with infected snails(ha)

No. frames

surveyed

No.

frames with snails

No. dissected living snails

No. infected snails

Percentage of frames with living snails, % (95% CI)

Infection rate, % (95% CI)

I

2005

6966

5150

13

482

335 391

56 884

256 531

663

16.96 (16.83–17.09)

0.2584 (0.2388–0.2781)

2006

7462

5014

22

625

374 149

47 808

203 828

744

12.78 (12.67–12.88)

0.3650 (0.3388–0.3912)

2007

7110

4603

1

244

356 623

41 927

152 389

297

11.76 (11.65–11.86)

0.1949 (0.1728–0.2170)

2008

7372

4633

8

176

362 537

32 455

117 615

178

8.95 (8.86–9.05)

0.1513 (0.1291–0.1736)

2009

7395

4570

0

134

360 932

31 964

121 574

214

8.86 (8.76–8.95)

0.1760 (0.1525–0.1996)

2010

7087

4294

54

173

380 727

29 666

106 107

187

7.79 (7.71–7.88)

0.1762 (0.1510–0.2015)

II

2011

7009

4037

0

98

376 348

24 309

83 775

117

6.46 (6.38–6.54)

0.1397 (0.1144–0.1649)

2012

6974

3859

0

4

398 717

20 748

73 979

7

5.20 (5.13–5.27)

0.0095 (0.0025–0.0165)

2013

7157

4093

0

1

356 279

18 033

54 091

1

5.06 (4.99–5.13)

0.0018 (0.0000–0.0055)

2014

7248

4100

0

0

423 755

18 121

66 522

0

4.28 (4.22–4.34)

0.0000

2015

7571

4147

0

0

393 597

28 797

11 617

0

7.32 (7.24–7.40)

0.0000

Total

79 351

48 500

98

1937

4 119 055

350 712

1 350 028

2408

  1. ha hectare, CI Confidence intervals