Figure 7.

Risk area of NiV in the central plain of Thailand. Risk area of NiV produced by Potential Surface Analysis (PSA) based on i) flying fox distribution map, ii) distance to flying fox colonies, iii) house density and iv) pig farm density. The risk area of NiV for humans obtained from the first 3 factors (A), from all 4 factors (B), and the risk area of NiV for pigs produced by combining factors i, ii and iv (C). The yellow circles show different risk areas between B and C. Risk was low if the summation score was less than $\overline{x}-\sigma$, moderate if the summation score was range between $\overline{x}-\sigma$ and $\overline{x}-\sigma$, and high if the summation score was more than $\overline{x}-\sigma$.