Table 1.
Results of an EEHV1 real-time qPCR assay designed to specifically detect EEHV1A and EEHV1B in various samples from elephants with NAP infection for which archived samples were available.
| Elephant (source) | EEHV strain |
SYBR green CT* |
Hydrolysis probe CT† |
Test result | No. of VGCs‡ | VGCs/mL of blood§ | Clinical result |
|---|---|---|---|---|---|---|---|
| First archive elephant (heart) |
1A | 28.26 | 36.61∥ | Positive | 18 | NA | Death |
| First archive elephant (spleen) |
1A | 24.90 | 28.94∥ | Positive | 3 × 103 | NA | Death |
| NAP#26 (heart) | 1A | 18.81 | 22.92 | Positive | 1.8 × 105 | NA | Death |
| NAP#29 (heart) | 1A | 24.31 | 31.28∥ | Positive | 654 | NA | Death |
| Second archive elephant (blood) |
1A | 30.91 | 35.40 | Positive | 41 | 1 × 104 | Clinically ill |
| NAP#31 (blood) | 1A | 21.11 | 23.72 | Positive | 1 × 105 | 2.6 × 107 | Death |
| NAP#19 (blood) | 1A/B | 23.95 | 27.92 | Positive | 1.3 × 104 | 3.4 × 106 | Death |
| NAP#33 (blood) | 1B | 23.19 | 28.72 | Positive | 8 × 103 | 2 × 106 | Clinically ill |
| NAP#34 (blood) | 1B | 27.24 | 32.45 | Positive | 647 | 1.6 × 105 | Subclinically infected |
| NAP#27 (kidney) | 3 | 33.32 | U | Negative | NA | NA | Death |
| NAP#22 (blood) | 4 | 33.28 | U | Negative | NA | NA | Death |
SYBR green reaction parameters: regression equation, y = −3.324x + 37.181; R2 = 0.999; assay efficiency, 99.9%.
Hydrolysis probe reaction parameters: regression equation, y = −3.421x + 40.911; R2 = 0.999; assay efficiency, 96.0%.
Double-stranded copies of target DNA in individual test reactions based on a qPCR assay with hydrolysis probes; equivalent to VGCs.
Viral genome copy per milliliter of blood calculated on the basis of known amount of genomic DNA yield from 200 μL of whole blood used in clinical assays.
Because of a limited sample supply, samples used in hydrolysis probe assays were diluted 1:10 in double-distilled water relative to SYBR green.
NA = Not applicable. U = Undetectable (samples did not yield a reaction that crossed the threshold signaling a productive PCR resulting in an undetermined CT; CT for nontemplate control reactions was undetermined for all hydrolysis probe assays and was ≥ 35 for SYBR green assays).