Table 2.
Summary of the experimental conditions of S. suis co-infection with viral pathogens using in vivo models
| S. suis co-infection parhogen | Age of pigs at the infection Virus / Bacteria |
Route of infection Virus / Bacteria |
Virus strain and dose | S. suis strain and dose | Main observed effects of co-infection | Ref | ||
|---|---|---|---|---|---|---|---|---|
| PRRSV | 19 days | 26 days | IN | IN |
2 × 104.99 TCID50, high virulent PRRSV strain, genotype 2 2 × 104.47 TCID50, low virulent PRRSV vaccine strain RespPRRS/Repro™ |
2 × 108.3 CFU; serotype 2 (no further details on the strain) | ↑ Severity of clinical signs, mortality, and interstitial pneumonia lesions (especially those infected with the high virulent PRRSV strain) | [61] |
| 98 days of sow gestation | 5 days | IN | IN | 103.5 TCID50, PRRSV, genotype 2 | 8 × 107 CFU, serotype 2 (no further details on the strain) | ↑ Susceptibility of piglets to bacterial infection | [52] | |
| 21 days | 28 days | IN/IM | IN/IM | 2 × 104.97 TCID50 PRRSV, genotype 2 | 109 CFU; serotype 7 (no further details on the strain) | ↑ Clinical signs and mortality | [65] | |
| 49 days | 42 days* | IN | IN |
2 × 104 TCID50 Asian HP-PRRSV strains; US PRRSV strains, genotype 2 |
106 CFU; serotype 2 (no further details on the strain) |
↑ Clinical severity related to PRRSV virulence; ↓ levels of proinflammatory cytokines |
[64] | |
| 28 days | 21 days* | IN | IM |
106 TCID50 PRRSV MLV-like strain |
2 × 108 CFU; serotype 2 low virulence strain (no further details on the strain) | ↑ Clinical signs and mortality | [67] | |
| SIV | 35 days | 38 days | IN | IN | 2 × 107 egg infectious dose50/mL, H1N1 strain | 2 × 106 CFU; serotype 2; ST7 | ↑ Clinical signs, pathological changes, and cell apoptosis; ↑ gene expression for pro-inflammatory mediators | [76] |
| PCV-2 | 28 days | 33 days |
IN/IM 2 mL/3 mL |
IN/IM 2 mL/3 mL |
2 × 106.5 TCID50 | 4.5 × 109 CFU; serotype 2; ST7 | ↑ Clinical signs; ↑ gene expression for pro-inflammatory mediators; ↓ gene expression for CD4, CD8, and MHC-II | [21] |
| PRV | 63 days | 63 days | IN | IN | 5 × 103 TCID50 high or low virulent PRV strains | 109 CFU S. suis serotype 2 (no further details on the strain) | ↑ Clinical signs | [107] |
* Animals were infected first with S. suis and then infected with a virus.
IM: intramuscular injection; IN: intranasal inoculation; PRSSV: Porcine Reproductive and Respiratory Syndrome Virus; SIV: Swine Influenza Virus; PCV-2: Porcine Circovirus type 2; PRV: pseudorabies virus; TCID50: medium tissue culture infectious dose; CFU: colony-forming units; ST: sequence type.