TABLE 3.
Assay | No. cases positive | Mean no. days (+ SEM) | Range (days) |
---|---|---|---|
ELISA antigen | 18 | 7.9 (0.8)a | 3–15 |
ELISA IgM | 36 | 13.1 (0.9)b | 4–31 |
ELISA IgG | 9 | 25.6 (3.0)c | 7–39 |
IFA | 34 | 13.1 (1.0)c | 4–31 |
Virus isolation | 50 | 8.0 (0.6)a | 3–22 |
P < 0.001 for comparison with ELISA IgM.
P < 0.005 for comparison with ELISA IgG.
P < 0.01 for comparison between IFA and ELISA IgG.