Table 3.

Spatial cluster analysis in Shandong Province, 2005–2015

Phase	Infection source	Code	No. of counties	Proposed cluster timeframe	No. of cases	Expected cases	Population (10,000)	RR	p
Control	Indigenous	a	13	Jan. 1 of 2006 to Dec. 31 of 2007	126	18.80	2165.7	9.78	<0.001
		b	1	Jan. 1 of 2008 to Dec. 31 of 2008	5	0.20	44.9	25.90	0.013
		c	1	Jan. 1 of 2005 to Dec. 31 of 2005	6	1.10	254.3	5.51	0.698
	Imported	d	2	Jan. 1 of 2005 to Dec. 31 of 2005	15	0.62	133.0	25.17	<0.001
		e	14	Jan. 1 of 2005 to Dec. 31 of 2005	20	9.29	1994.4	2.22	0.856
		f	1	Jan. 1 of 2008 to Dec. 31 of 2009	28	7.55	809.9	3.92	<0.001
		g	4	Jan. 1 of 2007 to Dec. 31 of 2007	15	3.91	840.2	3.95	0.037
		h	5	Jan. 1 of 2008 to Dec. 31 of 2009	45	4.49	481.1	11.23	<0.001
Elimination	Indigenous	i	1	Jan. 1 of 2010 to Dec. 31 of 2011	37	0.14	120.2	801.58	<0.001
		j	1	Jan. 1 of 2010 to Dec. 31 of 2011	4	0.46	411.7	9.19	0.732
	Imported	k	17	Jan. 1 of 2013 to Dec. 31 of 2015	236	68.53	2970.6	4.54	<0.001
		l	1	Jan. 1 of 2013 to Dec. 31 of 2015	17	2.48	107.5	6.99	<0.001
		m	11	Jan. 1 of 2013 to Dec. 31 of 2015	113	33.54	1453.7	3.78	<0.001