| Typicality: | 0.402 |
| Saliency: | 0.355 |
| for the first time in 1999 | 10 | temporal |
| few months later | 3 | temporal |
| virus → appear in → north america | 9 |
| virus → be detected in → north america | 5 |
| virus → appear in → the americas | 5 |
| virus → be detected in → the americas | 3 |
| negative | neutral | positive |
| 0.427 | 0.546 | 0.027 |
| Raw frequency | 22 |
| Normalized frequency | 0.355 |
| Modifier score | 0.500 |
| Perplexity | 125.746 |