TABLE I. Results of 90% plaque-reduction neutralisation test (PRNT90) for alphaviruses in equids of Pantanal, Brazil.
| Unvaccinated (n = 484) | Vaccinated (n = 264) | Total (n = 748) | ||||||
|---|---|---|---|---|---|---|---|---|
| ≥ 10 (%) | 4-fold greater criterion (%) | ≥ 10 (%) | 4-fold greater criterion (%) | ≥ 10 (%) | 4-fold greater criterion (%) | |||
| EEEV | 87 (18) | 48 (9.9) | 96 (36.4) | 47 (17.8) | 183 (24.5) | 95 (12.7) | ||
| WEEV | 8 (1.7) | 4 (0.8) | 42 (15.9) | 15 (5.7) | 50 (6.7) | 19 (2.5) | ||
| VEEV | 4 (0.8) | 1 (0.2) | 1 (0.4) | 1 (0.4) | 5 (0.7) | 2 (0.3) | ||
| MAYV | 36 (7.4) | 10 (2.1) | 8 (3) | 0 (0) | 44 (5.9) | 10 (1.3) | ||
| ALPHA | - | 50 (10.3) | - | 54 (20.4) | - | 104 (13.9) | ||
| NEG | - | 371 (76.7) | - | 147 (55.7) | - | 518 (69.3) | ||
ALPHA: undetermined alphavirus; EEEV: eastern equine encephalitis virus; MAYV: Mayaro virus; NEG: PRNT90 titre < 10 to all four alphaviruses; VEEV: Venezuelan equine encephalitis virus; WEEV: western equine encephalitis virus.