Student guest post: Chirp, Chirp, Sneeze!

Student guest post by Julia Wiederholt

I don’t think there is a single person that can claim to have never had the joyous experience (sarcasm intended) of suffering from the influenza.  We all recognize the common symptoms that accompany this infectious little virus taking up residence in our bodies: the chills accompanying a fever, the total body ache, the nausea, and overall feeling of malaise.  Typically this virus comes and goes within a week without serious side effects.  When novel strains of the influenza pop up however, there can be more serious complications as your body lacks a sufficient immune recognition of the virus.  An example of a new strain of influenza that presents a great risk for the human population is the H7N9 influenza, also known as Avian Influenza A.

H7N9 was first recognized earlier this year in China and thankfully has yet to be reported in the US. The majority of the people infected have had direct contact with poultry or an environment that has contained infected poultry.  Some of the people diagnosed however, report having had no direct contact with poultry opening up the possibility of human to human transfer of the disease.  The infected poultry have shown no obvious symptoms of being infected, but when humans become infected it can cause severe respiratory problems and fever.  As of May this year, LiveScience reported that there have been a total of 131 reported human cases of H7N9 with 32 reported deaths.

While all of that may not sound too impressive, here’s what makes H7N9 such a concern as an emerging infectious disease.  The first major concern regarding this specific influenza is the fact that it is the first time the H7N9 virus has been reported in humans.  The H in the name H7N9 stands for hemaglutinin, which is the attachment protein found on influenza viruses.  This protein not only enables the virus to attach to the cells it is trying to infect, it also is provides the host’s immune system a way of recognizing the virus as a foreign threat.  The fact that this is the first time this specific virus has been found to infect humans means that we lack any prior immunity to it and are therefore, more susceptible.

Another factor that raises the alarm for this influenza is the fact that the infected poultry that have been found so far have shown no outward signs of being sick.  This is a huge concern because it makes controlling the spread of the disease much more difficult.  When poultry and livestock exhibit obvious signs of being infected, it allows the infected to be separated out from the healthy and either isolated or culled to prevent further spread of the disease.  In some cases, the disease may have already spread amongst all of the animals in the vicinity requiring the entire herd or flock to be culled.  When it is difficult to distinguish between healthy and infected animals however, any evidence that the disease has been found within the animals will more than likely lead to the entire herd or flock being culled.  This not only results in greater economic losses for the poultry farmers but also a higher number of people being exposed to infected animals before realizing the danger that is present.

Possibly the greatest concern with H7N9 is the fact that it could be jumping from person to person.  The original thought was that the only way it had been spreading was from direct contact with sick poultry, which would limit the at risk human population to people coming into contact with the infected birds.  Some of the people who have been diagnosed with H7N9 however, are claiming to have had no contact with poultry suggesting that the disease may be capable of human to human transmission.  This would greatly increase the reproductive rate of the disease because people would no longer need to come into contact with poultry to be exposed to it.  The reproductive rate, commonly referred to in scientific communities as the Ro, is a way of measuring the predicted number of new infections that one infectious case is likely to create.  Another factor that suggests the possibility of human to human transfer is the fact that there have been three reported family clusters of H7N9.  While this does not necessarily mean that the virus is capable of sustained human to human transfer, it is highly suggestive that human to human transmission has occurred in these particular instances and that with the right (or depending on how you look at it, wrong) mutation, it could transfer between humans with ease.

While all of these things explain why H7N9 is being watched so closely and why it is important to have a healthy respect for just how dangerous it could be, there’s no reason for people to start panicking quite yet.  As mentioned earlier, this strain of influenza has only been reported in people that either live in or have recently traveled to China.  Unless you are planning to travel out of the country in the near future, there is no reason to become overly concerned about H7N9 at the moment.  Also, the majority of the cases have either had direct contact with infected poultry or close contact with someone who has had contact with poultry.  This means that unless the virus becomes proficient at human to human transmission, the majority of the population is at a low risk.

For the germaphobes out there that are still freaking out over the possibility of catching H7N9, there are several ways to reduce the risk of catching it, or any other influenza for that matter.  Good hygiene practices such as frequently washing your hands and avoiding touching your face will help minimize the risk of introducing the influenza virus into your body.  Eating a well-balanced diet and getting plenty of rest will help keep your immune system in tip top shape in the event of a virus managing to get past your innate defense mechanisms.  In regards to reducing the risk of catching a zoonotic strain of influenza, practices such as thoroughly washing your hands after handling any animals and avoiding contact with sick poultry or livestock will reduce the risk of transmission.  So rest at ease, the world isn’t coming to an end due to H7N9…at least not yet.

Sources

Cong Dai, Min Jiang, “Understanding H7N9 Avian Flu,” BMJ, Available online 3 May 2013.  <http://www.bmj.com.proxy.lib.uiowa.edu/content/346/bmj.f2755?view=long&…;.

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Guang-Wu Chen, Michael M.C. Lai, Suh-Chin Wu, Shih-Cheng Chang, Li-Min Huang, Shin-Ru Shih, “Is avian influenza A (H7N9) virus staggering its way to humans?”, Journal of the Formosan Medical Association, Available online 3 June 2013, ISSN 0929-6646, 10.1016/j.jfma.2013.04.015. <http://www.sciencedirect.com/science/article/pii/S0929664613001654&gt;.

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Kannan Tharakaraman, Akila Jayaraman, Rahul Raman, Karthik Viswanathan, Nathan W. Stebbins, David Johnson, Zachary Shriver, V. Sasisekharan, Ram Sasisekharan, “Glycan Receptor Binding of the Influenza A Virus H7N9 Hemagglutinin,” Cell, Available online 6 June 2013, ISSN 0092-8674, 10.1016/j.cell.2013.05.034. <http://www.sciencedirect.com/science/article/pii/S0092867413006405&gt;.

Rettner, Rachael. "H7N9 Bird Flu Cases Declining, Health Officials Say." LiveScience. N.p., 10 May

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