TABLE 4.

Clinical variables (geometric mean ± SD) and antibody titer to E. equi antigen in 38 sheep infected with different variants of A. phagocytophila

A. phagocytophila variant(s)nResult (mean ± SD)
Rectal temp (°C)No. of neutrophils (109 cells/liter)aAbsolute no. of infected neutrophils (109 cells/liter)aNo. of seropositive sheepb (%)Mean antibody titer in seropositive sheep
A. phagocytophila variant 114c40.74 ± 1.0150.80 ± 0.1820.024 ± 0.004 (3.1 ± 2.91)13 (93)1:386
A. phagocytophila variant 22140.64 ± 1.0141.48 ± 0.2270.193 ± 0.006 (13.1 ± 3.07)9 (43)1:320
A. phagocytophila prototype and variant 1241.54 ± 1.0051.38 ± 1.1540.067 ± 0.013 (4.6 ± 1.53)2 (67)1:452
A. phagocytophila variant 1 and variant 5140.401.620.008 (0.5)0Negative
  • a The number of neutrophils and infected neutrophils in sheep infected with A. phagocytophila variant 1 and those infected with A. phagocytophila variant 2 were significantly different: P < 0.03 and P < 0.004, respectively. Percent values are given in parentheses.

  • b Comparison of A. phagocytophila variant 1 and A. phagocytophila variant 2: Yates corrected χ2 = 6.98 and P < 0.01.

  • c Clinical data from one of the A. phagocytophila variant 1-infected sheep were not available.