Several published reports indicate that the principal mechanism by which carrageenans block virus infectivity is by direct binding to the viral surface [35], [36], [38], [40].
29 This almost certainly underestimates the effect of the interventions, given that influenza infectivity is highest soon after infection.
The percentage of HIV infections attributable to infection with chlamydia is also higher if chlamydia infectivity is higher, because chlamydia incidence is then higher and that intensifies the interaction with HIV; however, the percentage is lower if HIV infectivity is higher, since then the dynamics of HIV transmission are quite strong and can hardly be affected by chlamydia.
Elevation of the pH at these steps renders the incoming virus infection-defective and the secreted virus infectivity is decreased by three orders of magnitude [ 49].
As expected, antibody was poorly effective against either virus infecting GAG− CHO cells (where wild-type infectivity is anyway low).
Infectivity is modeled as the area around an infected agent in which another agent is at risk of becoming infected.
Infectivity is quantified by calculating the number of infected cells using an enzyme-linked immunospot (ELISPOT) assay based on the immunodetection of PrPSc.
When the infected individual is in the acute or AIDS stages, the infectivity is increased through multiplying by δ a or δ b, respectively.
In the absence of treatment, infectivity is estimated to be 9 times higher in early HIV infection and 7 times higher in late HIV infection [ 36].
Infectivity is given by the proportion, β, of susceptible individuals who become infected by the initial case.
If hepatitis D infectivity is low, then hepatitis D superinfection will mostly occur during chronic HBV infection; that reduces HBV infectivity and hence HBV prevalence.
