The results of experiments comparing the virulence in animals of the 2009 H1N1 influenza virus with seasonal strains have spawned the headline Study Suggests H1N1 Virus More Dangerous Than Suspected. In my view, the best experiment is now being done in humans: infection of millions with the pandemic virus. The results show that the virus …
Is the 2009 H1N1 influenza virus more dangerous than we think? Read More »
The plaque assay is a terrific method for determining virus titers, but it doesn’t work for all viruses. Fortunately there are several alternative methods available, including the end-point dilution assay. The end-point dilution assay was used to measure virus titer before the development of the plaque assay, and is still used for viruses that do …
Measurement of viruses by end-point dilution assay Read More »
Tamiflu (Oseltamivir) is one of the few antiviral drugs available for treatment of influenza. Use of the drug has increased substantially because of the emergence of the 2009 H1N1 pandemic strain, against which no vaccine is yet available. A recent study has shown that low levels of oseltamivir can be detected in the aquatic environment. …
The plaque assay is an essential tool for determining virus titers. The concept is simple: virus infection is restricted to neighboring cells by a semisolid overlay. By counting the number of plaques, the virus titer can be calculated in PFU per ml. A key question is: how many viruses are needed to form a single …
One of the most important procedures in virology is measuring the virus titer – the concentration of viruses in a sample. A widely used approach for determining the quantity of infectious virus is the plaque assay. This technique was first developed to calculate the titers of bacteriophage stocks. Renato Dulbecco modified this procedure in 1952 …
The immune response to viral infection comprises innate and adaptive defenses. The innate response, which we have discussed previously, functions continuously in a normal host without exposure to any virus. Most viral infections are controlled by the innate immune system. However, if viral replication outpaces innate defenses, the adaptive response must be mobilized. The adaptive …
