Table 3.
Clusters of indigenous and imported malaria cases in Hubei Province, 2005–2016
| Phase | Infection source | Type of cluster | No. counties | Radius (km) | Time frame | Number of cases | Expected cases | Relative risk | Log likelihood ratio | P value |
|---|---|---|---|---|---|---|---|---|---|---|
| 2005–2010 | Indigenous | A | 13 | 119.54 | 2005/4/1 to 2007/11/30 | 4273 | 532.72 | 18.58 | 6510.03 | 0.000 |
| Imported | A | 1 | 0 | 2007/9/1 to 2007/9/30 | 24 | 0.026 | 1071.73 | 141.41 | 0.000 | |
| B_1 | 1 | 0 | 2008/4/1 to 2008/4/30 | 5 | 0.022 | 233.49 | 22.21 | 0.000 | ||
| B_2 | 3 | 38.06 | 2010/6/1 to 2010/8/31 | 7 | 0.12 | 61.33 | 21.77 | 0.000 | ||
| B_3 | 1 | 0 | 2008/6/1 to 2010/11/30 | 11 | 0.63 | 18.84 | 21.52 | 0.000 | ||
| 2011–2016 | Indigenous | A | 11 | 116.4 | 2011/1/1 to 2011/9/30 | 68 | 4.95 | 54.99 | 149.05 | 0.000 |
| Imported | A | 6 | 16.43 | 2012/8/1 to 2015/7/31 | 159 | 32.66 | 5.91 | 137.17 | 0.000 | |
| B_1 | 1 | 0 | 2012/6/1 to 2015/5/31 | 40 | 3.31 | 12.71 | 63.90 | 0.000 | ||
| B_2 | 1 | 0 | 2012/3/1 to 2014/4/30 | 13 | 1.68 | 7.83 | 15.33 | 0.007 | ||
| B_3 | 1 | 0 | 2014/12/1 to 2015/1/31 | 5 | 0.12 | 43.56 | 13.97 | 0.022 |
A: Most likely cluster; B: Secondary cluster