TABLE 2.

Serum titers of IgG to E. phagocytophila in 70 calves, heifers, and cows in an area endemic for tick-borne fever from April 1996 to March 1997

Mo	No. of animals with the following titera:
	<20	20	40	80	160	320	640	1,280
April	57 (14, 16, 27)	8 (0, 4, 4)	4 (0, 1, 3)	1 (0, 1, 0)	0	0	0	0
May	59 (14, 17, 28)	9 (0, 4, 5)	2 (0, 1, 1)	0	0	0	0	0
June	40 (9, 12, 19)	3 (1, 1, 1)	9 (2, 2 [1], 5)	11 (2, 5 [1], 4 [1])	4 (0, 1, 3 [2])	3 (0, 1, 2)	0	0
July	32 (7, 9, 16)	2 (1, 0, 1)	11 (2, 5, 4)	10 (2, 4 [1], 4 [2])	9 (2, 3 [1], 4 [1])	1 (0, 0, 1)	5 (0, 1, 4 [2])	0
August	29 (6, 8, 15)	3 (0, 1, 2)	5 (2, 2, 1)	10 (1, 4 [1], 5)	11 (2, 4 [1], 5 [1])	5 (2, 1, 2 [1])	6 (1, 2, 3 [2])	1 (0, 0, 1 [1])
September	26 (5, 8, 13)	3 (1, 0,2)	5 (2, 1, 2)	12 (1, 5, 6 [1])	8 (1, 3 [1], 4 [1])	7 (2, 1, 4 [2])	8 (2, 3 [1], 3 [2])	1 (0, 1, 0)
October	27 (5, 9, 13)	5 (2, 2, 1)	11 (2, 2 [1], 7 [1])	9 (1, 4, 4)	9 (2, 2 [1], 5 [3])	7 (2, 2, 3 [1])	2 (0, 1, 1 [1])	0
November	28 (6, 9, 13)	15 (2, 8 [2], 5)	9 (1, 1, 7 [1])	8 (3, 1, 4 [3])	6 (2, 1, 3 [1])	3 (0, 2, 1 [1])	1 (0, 0, 1)	0
December	38 (8, 14, 16)	11 (1, 4, 6 [1])	10 (3, 1, 6 [1])	8 (2, 2, 4 [2])	2 (0, 0, 2 [1])	1 (0, 1, 0)	0	0
January	46 (9, 16, 21)	8 (3, 2, 3 [1])	12 (2, 2, 8 [2])	3 (0, 1, 2 [1])	1 (0, 1, 0)	0	0	0
February	51 (9, 17, 25)	14 (5, 3, 6 [1])	4 (0, 1, 3 [1])	0	1 (0, 1, 0)	0	0	0
March	54 (10, 18, 26)	12 (4, 3, 5 [2])	4 (0, 1, 3)	0	0	0	0	0

^aReciprocal of the serum dilution. Numbers of calves, heifers, and cows, in that order, are indicated in parentheses; numbers of animals pastured on the fields of endemicity for the first time are indicated in brackets.