| Age (year) | No. tested samples | No. positive samples | Prevalence (%) |
| 1 - 2 | 98 | 71 | 72.4 |
| 3 - 4 | 156 | 128 | 82.1 |
| >4 | 237 | 198 | 83.5 |
| No record | 115 | 89 | 77.4 |
| Total | 606 | 486 | 80.2 |