Table 1. Detection of HFRS Clusters in Hubei Province, China.

Time-frame	Cluster	Cluster date	LLR	Observeda	Expectedb	RR	P-value
1980–1989	1	1982–1985	27145.13	33757	8150.17	6.18	<0.001
	2	1983–1985	3088.14	8840	3462.18	2.73	<0.001
	3	1981–1982	72.78	491	270.16	1.82	<0.001
1990–1999	1	1990–1994	2582.38	1637	140.55	12.63	<0.001
	2	1994–1998	1450.86	5302	2484.88	2.56	<0.001
	3	1993–1997	651.45	1696	626.06	2.87	<0.001
	4	1998–1999	331.50	327	51.39	6.46	<0.001
	5	1990–1991	172.89	367	116.21	3.20	<0.001
	6	1997	2.37	241	208.93	1.16	<0.001
2000–2009	1	2000–2003	829.66	422	23.94	19.21	<0.001
	2	2001–2005	577.73	329	23.11	15.20	<0.001
	3	2000–2002	482.54	1053	365.27	3.40	<0.001
	4	2000–2001	155.11	118	13.16	9.16	<0.001
	5	2000	0.23	72	66.42	1.09	= 1.000

LLR, Log likelihood ratio; RR, relative risk.

^aNumber of observed cases in a cluster.

^bNumber of expected cases in a cluster.