In another case, individual screening was triggered, and NAT was done, but before the screening results were received, a granulocyte unit was released for transfusion use; testing results later showed that the WNV load was sufficient for detection by NAT of pooled and individual blood samples (16 ).
However, another more recent study found the opposite effect, with TLR3 knockout mice being more susceptible to WNV infection and having higher viral load in the brain, although IFN levels in these mice were not diminished (Daffis et al. 2008).
To have a better understanding of the frequency of CD8+ T cells specific for the six HLA-A*0201 HLA-A*0201es, WNVgenerated peptidesMHC multimers loaded weth each of the peptides described (Table 1).
Overall, our evaluation of viral loads in 11 organs of WNV-infected carcasses supports the current prioritization of brain or kidney for selective organ testing for WNV (36 – 36 ).
However, high-titered viral loads (>10 PFU/0.5 cm) were found for both WNV strains in brain, heart, spleen, kidney, lung, and skin of sparrows and grackles (Table 3).
Our results demonstrate, as predicted by the trade-off hypothesis of virulence, decreased survival of Cx. pipiens with increasing viral load of mosquito-adapted West Nile virus (WNV MP20), but not its parental strain, WNV WT, in terms of survival, as well as an equivalent cost for resisting infection with this strain.
As a whole, jackdaws were less susceptible than the carrion crows to the same selection of otherwise highly virulent WNV strains, and they had lower death rates and virus loads in blood and organs (30 ).
Relatively high viral loads in tissues of birds infected with Tabasco or Tecate WNV strains (i.e., loads greater than or equal to those of birds infected with WNV NY99) (12 ) could result in higher rates of oral transmission to predatory or carrion-eating vertebrates, even if mosquito-borne transmission is less supported in tropical than in temperate regions.
As predicted by the trade-off hypothesis of virulence, costs of infection with WNV MP20 in terms of survival were directly correlated to viral load, yet resistance to infection with this virulent strain was equally costly.
Specifically, earlier mean mortality of the MP20-infected mosquitoes equates to fewer days of WNV replication in these individuals and an understatement of differences in viral load.
