New England Journal of Medicine Summary/Opinion

Epidemiology is the study of the outbreaks of disease and viruses in populations. By determining how viruses spread scientists who study these outbreaks can get a clearer picture on how to prevent them in the first place. A virus can spread quickly through a household due to the close parameters of the people who live there. To gather more data on the 2009 H1N1 pandemic, 348 index patients were recruited to be tested to verify that they had acute respiratory illness. Index patients are just the first patients who have been medically identified to have a given illness. Nasal and throat swabs were taken from all the people who lived in the same homes as the ones originally tested. Swabs were taken again at three and six days after the initial visit.

Reverse-transcriptase-polymerase-chain-reaction, the most sensitive means detecting mRNA to look for any existing signs if viral infection. Hemagglutination-inhibition and viral neutralization measures of the ability of soluble antigen to inhibit the agglutination of antigen-coated red blood cells by antibodies. In this test, a fixed amount of antibodies to the antigen in question is mixed with a fixed amount of red blood cells coated with the antigen. Different amounts of the sample to be analyzed for the presence of the antigen are included in the substance. If the sample contains the antigen, the soluble antigen will compete with the antigen coated on the red blood cells for binding to the antibodies, thereby inhibiting the agglutination of the red blood cells. 

Agglutination is simply the clumping of bacteria, red blood cells, or other cells, due to the introduction of an antibody. These tests yielded results that exposed the fact that seasonal influenza spreads at a similar rate and shares other traits with the H1N1 virus based on the viruses ability to spread successfully from person to person (transmittable and viral shedding) and the amount of people it can infect (clinical illness). In another test viral culture was examined to determine its infectious viral load. This tissue-culture infectious dose or TCID measures the quantity of virus that it takes to invoke a cytopathic effect of 50% in inoculated cultures.

A cytopathic change occurs in a cell when pathological culture, such as a virus, is able to alter or change the cell in some way. An inoculated culture is a sample of cells that has been exposed to a weak pathogen so that they can generate an immunity to the virus. In a similar experiment 374 patients with the seasonal influenza virus were given either oseltamivir, an antiviral agent or a placebo, a fake vaccine that doesn't do anything. The placebo is to eliminate the factor of people thinking they feel because they are getting treatment. The results showed that it is possible that a reduced amount of viral antigen can stimulate a enhanced response from antibodies after a similar virus has been introduced into the body.

In the future, viral epidemiology will be able to reveal much more and will be able to help prevent extreme pandemics potentially worse than the one in 2009 of H1N1. By following patterns such as how pandemic influenza is more likely to transmit among children, the correct measures can be taken early on to provide inoculation and proper sanitation. In conclusion; by tracking viral outbreaks it may be possible to contain and prevent mass-pandemics of diseases.

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