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. Author manuscript; available in PMC: 2009 Mar 1.
Published in final edited form as: Acta Trop. 2007 Dec 8;105(3):235–241. doi: 10.1016/j.actatropica.2007.12.002

Table 1.

Descriptive statistics of 147 sites where quantitative snail sampling was conducted in villages mostly rain-fed and in villages using some man-made irrigation systems, Samar Province, the Philippines 2002–2004.

Rain fed Irrigated Difference of the means (95% CI for difference)
No. of sites 91 56
No. of snails collected 7723 5080
Mean number of snails m−2 (range) 197.69 (23.29 to 619.45) 209.59 (25.62 to 654.38) −0.02 (−0.10 to 0.07)**
Proportion of young snails (range) 0.31 ( 0.00 to 0.71) 0.28 (0.00 to 0.73) 0.03 (−0.03 to 0.09)*
No. of snails infected 73 67
No. (%) of sites with infected snails 30 (33.0) 25 (44.6) 0.12 (−0.05 to 0.28)*
No. of infected snails m−2 (range) 1.87 ( 0.00 to 25.62) 2.79 ( 0.00 to 25.62) −0.06 (−0.24 to 0.11)**
Median proportion of snails infected per site (range)
     Total snails 0.00 ( 0.00 to 0.19) 0.00 ( 0.00 to 0.27) −0.01 (−0.02 to 0.00)
     Small snails 0.00 ( 0.00 to 0.05) 0.00 ( 0.00 to 0.13) −0.00 (−0.01 to 0.00)
     Large snails 0.00 ( 0.00 to 0.27) 0.02 ( 0.00 to 0.38) −0.01 (−0.02 to 0.01)
*

95% CI calculated using a binomial distribution

**

difference on a log(10)-scale