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What You Need To Know About Avian Influenza H7N9

02/01/2015 10:35 EST | Updated 04/03/2015 05:59 EDT
Trevor Williams via Getty Images

It happened again.

Last week, Canadian public health officials announced the arrival of yet another potentially deadly virus on our soil. This time, the culprit was a form of influenza -- avian influenza to be exact -- known as H7N9. This marked the second time in a year a deadly influenza virus had traveled from the Far East to Canada. Last year, the potentially deadly H5N1 influenza came to Alberta and sadly took a life.

The H7N9 virus is a relatively new strain of the well-known influenzas. It first appeared in China back in the early part of 2013 and caused an outbreak affecting 132 people and more importantly, taking 44 of those lives. The virus immediately became a concern due to its high mortality rate. Since then, the overall number of people infected is over 450 and at least 175 have died.

A closer inspection of the virus revealed its mode of infection was a hybrid of regular and highly pathogenic strains. Acquiring the infection was similar to H5N1: it's not easy. From an analysis of the cases since 2013, many occurred due to close contact with live birds. Though this is not a regular practice in Canada, in China, it is seen as a part of life. As for human to human transmission, no indication of sustained spread was found. Though people could get it from each other, a combination of close contact and sharing of fluids -- for example, kissing -- would be required.

After H7N9 enters the body, the infection progresses much like a bad seasonal flu similar to the H1N1 pandemic. The virus infects the respiratory tract and initiates the usual infection. In response, the body's immune system acts with a combination of inflammation mechanisms including fever and the production of a number of antibodies to combat the invasion.

As with the regular flu, the worst symptoms occur in the very young, the elderly and those who have weakened immune systems. With proper medical attention including the use of antivirals, the infection can be stopped and an individual can recover. Yet in the case of H7N9, the mortality rate was much higher although few reasons were known.

The answer came last year with an analysis of people who suffered greatly from the infection. The virus, much like H1N1, caused significant inflammation in the lungs. This not only allowed secondary bacterial infections to occur but also led to two very life-threatening conditions.

The first is complete respiratory distress in which the body simply no longer can breathe. The second is a condition known as systemic inflammatory response syndrome (SIRS) in which the immune system begins to shut down both itself and the body. This was seen during the 2009 pandemic particularly in those with pre-existing conditions. Thankfully, due to the experience of H1N1, Canada now has a system in place to deal with both consequences in order to keep people safe in the direst of times.

While H7N9 was being analyzed, public health officials were happy the virus had only been encountered in the Eastern provinces of China. Yet knowing the potential of many traveling diseases, such as SARS, the Middle East Respiratory Syndrome coronavirus, the aforementioned H5N1, and as demonstrated last year, Ebola, the Canadian government was not going to ignore the situation. They had been monitoring the situation for quite some time and were ready when the inevitable occurred. Perhaps for this reason, the arrival of the virus was met not with panic, but resilience.

Though health officials appear to be ready, the arrival of this virus may once again give some Canadians ill-ease. But there appears to be no reason for worry. All indications suggest the Canadian case was imported from China and has not been established here. Also, due to the very low potential for spread, anyone infected with the virus would most likely not pose a threat to the general public. As for anyone who might have the rare circumstance of having the illness, the medical system is prepared to treat.

The only real concern lies with those who will be travelling to the Eastern regions of China during the fall and winter months. From the data collected over the last two years, the virus is seasonal and outbreaks occur around this time. Based on recommendations from the World Health Organization, the only activities to be second-guessed involve close contact with live poultry. If hygiene practices have not been implemented, one might wish to eschew the area if only as a precaution.

The overall effect of H7N9 in Canada at this stage minimal yet does reveal the global nature of infectious disease. Microbes do not respect human borders and enjoy travel as much as their hosts. Although in the few cases where a foreign virus has come to Canada the consequences have been negligible, we do have to remember to stay diligent in monitoring and surveillance efforts. Though another SARS has not come, we do not want to be left unprepared in the event it happens.

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