Now that we have a rudimentary understanding of influenza virus replication, we can begin to consider how the virus causes disease – a field of study called viral pathogenesis. The first step in this process is virus entry into the body. The human body is covered with skin, which has a dead outer layer that …
The recent series of posts on polymerase error rates and viral evolution has elicited many excellent and thought provoking comments from readers of virology blog. Here is one that I had not thought of before, and which I’ll use on an exam in my virology course: Here’s a tough question. In the follow up blog …
Why don’t DNA based organisms discard error repair? Read More »
Our discussion of influenza virus replication has so far brought us to the stage of viral RNA synthesis. Last time we discussed the formation of viral RNAs, an event which takes place in the cell nucleus. Now we’ll consider how these RNAs participate in the assembly of new infectious viral particles, as illustrated in the …
Although the new influenza H1N1 strain has been receiving a great deal of attention, apparently last season’s H1N1 and H3N2 strains continue to circulate, at least in the United States. FluView, the weekly surveillance report from the CDC, indicates that during weeks 17 and 18, seasonal influenza A (H1), A (H3), and B viruses are …
Co-circulation of three human influenza A subtypes Read More »
We have spent over a week discussing the effects of polymerase error rates on viruses. RNA viruses have the highest error rates in nature, a property that is believed to benefit the viral population. For example, selective pressure from the immune system or antiviral drugs may lead to changes that are beneficial for the population. …
The capacity of RNA viruses to produce prodigious numbers of mutations is a powerful advantage. But remember that selection and survival must balance genetic fidelity and mutation rate. Many mutations are not compatible with viral replication. Consequently, if mutation rates are high, at some point accumulating base changes lead to lethal mutagenesis – the population …
