TABLE 5.

Risk indices for B. burgdorferi and the agent of HGE in the lower Hudson Valley region in 1996

County	Sitea	Risk index
		B. burgdorferi	Ehrlichia sp.	Combined
Westchester	1	0	0	0
	2	11.6	14.5	30.4
	3	8.7	3.3	13.0
	4	5.3	4.6	11.9
	5	0	1.6	1.6
	Mean	5.1 (5.18)b	4.8 (5.69)	11.4 (12.14)
Putnam	3	0.4	0.4	0.9
	4	0.8	0.8	1.6
	5	0	2.2	2.1
	6	2.5	2.2	4.7
	7	4.6	2.6	7.2
	Mean	1.7 (1.9)	1.6 (0.97)	3.3 (2.61)
Dutchess	4	0.7	1.3	2.5
	5	6.4	0	6.4
	6	2.9	2.6	5.5
	7	0.5	1.8	2.3
	8	0.5	0.8	1.3
	Mean	2.2 (2.56)	1.3 (0.98)	3.6 (2.22)
Rockland	1	2.1	0.9	3.5
	2	1.2	0.2	1.6
	3	1.1	0.2	1.4
	4	0.4	0.2	0.6
	5	1.3	1.4	2.9
	Mean	1.2 (0.61)	0.6 (0.55)	2.0 (1.18)
Orange	5	0.1	0.3	0.4
	11	0.04	0.3	0.3
	12	0.5	0.9	1.5
	13	0.2	0.4	0.6
	Mean	0.2 (0.2)	0.5 (0.29)	0.7 (0.55)
Ulster	2	0.3	0.04	0.3
	3	0.1	0.2	0.2
	Mean	0.2 (0.16)	0.1 (0.11)	0.3 (0.07)

^aThe locations of sites are shown in Fig. 1. 

^bThe values in parentheses are standard deviations.