TABLE 1.
Microscopy results for thin blood smears as differences between samples from cows with low, intermediate, or normal PCVa
| Microscopic finding | No. of positive animals/no. of animals tested (% of positive animals)
|
Pb | ||
|---|---|---|---|---|
| Group I | Group II | Group III | ||
| Basophilic stippling in RBCs | 74/95 (78) | 24/48 (50) | 1/142 (1) | <0.0001 |
| Fine stipples | 43/95 (45) | 9/48 (19) | 0/142 (0) | <0.0001 |
| Intermediate stipples | 35/95 (37) | 13/48 (27) | 1/142 (1) | <0.0001 |
| Large stipples | 39/95 (41) | 8/48 (17) | 0/142 (0) | <0.0001 |
| Inclusions in RBCs | ||||
| A. marginale | 94c/95 (99) | 35/48 (72) | 5/142 (4) | <0.0001 |
| Large Babesia spp. | 5/95 (5) | 0/48 (0) | 3/142 (2) | NS |
| Small ovoid | 12/95 (13) | 3/48 (6) | 0/142 (0) | 0.0001 |
| Small round with tail | 31/50 (62) | 14/20 (70) | 1/17 (6) | <0.0001 |
| A. phagocytophilum inclusions in WBCs | 2/95 (2) | 0/48 (0) | 0/142 (0) | NS |
a
Blood smears for 285 cattle were tested. No blood smear was available for one cow. Abbreviations: WBC, white blood cells; NS, not significant.
b
P values were determined by chi-square analysis.
c
Animal 96 tested negative for A. marginale by microscopy, serology, and PCR.