Table 4.
Results from Dirofilaria immitis (Di) antigen (Ag) and microfilariae (MF) tests on dogs for naturally occurring heartworm infection. In each study listed, microfilariae were confirmed as Dirofilaria immitis by acid phosphatase stain or by PCR unless otherwise noted
| No. of dogs (% positive)a |
Di Ag + Di MF + (%) |
Di Ag + Di MF - (%) |
Di Ag - Di MF + (%) |
Di Ag - Di MF - (%) |
Reference |
|---|---|---|---|---|---|
| 630 (16.2)b | 42 (6.7) | 23 (3.7) | 37 (5.9)b | 555 (88.1) | [13] |
| 696 (15.1) | 49 (7.0) | 16 (2.3) | 41 (5.9) | 591 (84.9) | [14] |
| 304 (27.3) | 56 (18.4) | 22 (7.2) | 5 (1.6) | 221 (72.7) | [15] |
| 24 (62.5) | 6 (25.0) | 4 (16.7) | 5 (20.8) | 9 (37.5) | [16] |
| 404 (12.1) | 21 (5.2) | 25 (6.2) | 3 (0.7) | 355 (87.9) | [24] |
| 616 (7.6) | 24 (3.9)c | 21 (3.4) | 2 (0.3)b, c | 569 (92.4) | [31] |
| 104 (18.3) | 13 (12.5) | 5 (4.8) | 1 (1.0) | 85 (81.7) | [58] |
aPositive for Dirofilaria immitis by at least one laboratory method
bInferred from text description of reported results and prior to heat treatment of samples
cMicrofilariae identified by morphology alone