Table 3.
Oral infection experiments. Infection, dissemination and transmission rates for mosquitoes 14 days after oral exposure to USUV
| Species/(populations) | USUV Strain used | Blood meal titer (PFU/ml) (TCID50/ml) | Infection ratea | Dissemination rateb | Transmission ratec | Reference |
|---|---|---|---|---|---|---|
| Culex neavei (Barkedji, Senegal) | SAAR 1776 | 2 × 107 | 33.3% (1/3) | 0% (0/1) | – | [86] |
| 2 × 107 | 22.2% (2/9) | 0% (0/2) | – | |||
| 2 × 107 | 0% (0/1) | – | – | |||
| 1.8 × 108 | 90.9% (40/44) | 40.0% (16/40) | 81.3% (13/16) | |||
| Culex pipiens (Brummen, The Netherlands) | USUV, Bologna '09 | 4 × 107 | 80% | Not studied | 69% | [87] |
| Culex pipiens (Mercer County, NJ, USA) | SAAR 1776 | 1 × 107.5 | 58.6% (17/29) | 92.3% (12/13) | 23.5% (4/17) | [88] |
| Culex quinquefasciatus (Vero Beach, FL, USA) | SAAR 1776 | 1 × 106.95 | 70.0% (21/30) | 35.7% (5/14) | 19.0% (4/21) | [88] |
| Aedes albopictus (Mercer County, NJ, USA) | SAAR 1776 | 1 × 105.95 | 0% (0/27) | – | – | [88] |
| Culex pipiens form pipiens (Caldbeck, UK) Culex pipiens hybrid form (Brookwood, UK) | SAAR 1776 | 1 × 106 (25°) | 5% (1/20) | 5% (1/20) | 100% (1/1) | [89] |
| SAAR 1776 | 1 × 106 (25°) | 0% (0/18) | – | – | ||
| Aedes albopictus (Emilia-Romagna, Italy) | USUV1 | 0.66×107.5 | 0% (0/20) | – | – | [78] |
| USUV2 | 0.66×107.5 | 0% (0/20) | ||||
| USUV3 | 0.66×107.9 | 0% (0/19) |
PFU, plaque-forming unit; TCID50, tissue culture infectious dose 50%.
After 14 days incubation at 27–28 °C and 80% relative humidity (except for Hernández-Triana et al., 2018 for which both UK lines of Culex pipiens were tested for their vector competence for the SAAR-1776 strain of USUV at 25 °C), fed mosquitoes were analysed for USUV infection of their bodies (infection), of their legs and wings (dissemination), and the presence of virus in the saliva (transmission).
a
No. infected mosquito bodies/no. mosquitoes tested.
b
No. mosquitoes with infected wings and legs/no. infected mosquitoes.
c
Formerly named Aedes detritus