Volume 6, Number 4—August 2000
Dispatch
Ehrlichia chaffeensis Antibodies in White-Tailed Deer, Iowa, 1994 and 1996
Linda Mueller-Anneling*, Mary J. Gilchrist†, and Peter S. Thorne*
Table 2
Deer seropositivity for antibodies to Ehrlichia chaffeensis, Iowa, 1994 and 1996.
| Year | Result | North | Central | South | Statewide |
|---|---|---|---|---|---|
| 1994 | No. of samples | 444 | 617 | 714 | 1775 |
| % of population sampled | 0.59 | 0.57 | 0.51 | 0.55 | |
| No. positive | 6 | 26 | 189 | 221 | |
| % positive | 1.35 | 4.21 | 26.5 | 12.5 | |
| Est. no. of positive deer | 1,017 | 4,523 | 37,183 | 42,724 | |
| Odds ratio | 1.0 | 3.2 | 26.3a | ||
| 1996 | No. of samples | 318 | 374 | 410 | 1,102 |
| % of population sampled | 0.32 | 0.31 | 0.28 | 0.30 | |
| No. positive | 0b | 18 | 135 | 153 | |
| % positive | 0 | 4.81 | 32.9 | 13.9 | |
| Est. no. of positive deer | 0 | 5,782 | 48,919 | 54,701 | |
| Odds ratio | 1.0 | 16.1 | 156.1c |
aChi square for trend = 183, p<0.00001
bOne positive case was assumed for this cell to allow calculation of the odds ratio
cChi square for trend = 173, p<0.00001
