Mechanism of H7N9

We will be touching on the mechanism of H7N9 for this post. In an article posted on Journal of Virology, [A(H7N9) virus results in early induction of proinflammatory cytokine responses in both human lung epithelial and endothelial cells and shows increased human adaption compared with avian H5N1 virus.]. This article shows the comparison of the mechanism of H7N9 and H5N1 through a series of tests. This is so the pathogenic mechanism of H7N9 is not fully known yet.

This article states that in epithelial cells, it replicates efficiently while in pulmonary endothelial cells it efficiently initiated infection. The H7N9 virus is able to bud off from both kind of cells( ciliated and mucin-secretory cells).The fact that it is able to load itself on lung cells and “induction of host responses in endothelial cells”  these factors might be the reason for causing severe pulmonary disease. With the possibility of H7N9 accessing and damaging the lungs endothelial cells, this might be the cause of pneuomia once being infected.

In another article published in PLOS|ONE, titled  “Novel Avian Influenza A (H7N9) Virus Induces Impaired Interferon Responses in Human Dendritic Cells” has shown that since H7N9 was not able to efficiently induce antiviral Interferon, this results in the lack response that the body will have in the presence of the virus. The lack of regulation of interferon responses might also have been caused by  NS1. NS1 protein can block IRF3 and this affects the expression of again antiviral Interferon. These factors  lead to the virus being able to spread around the body easily and thus explaining the high level of virus present in the airway tissue. This being said, the low levels of interferon being demonstrated can also induce antiviral state in the human cells and H7N9 is also very sensitive to the low levels of IFN and thus sometimes IFN can be used as a kind of treatment.

In conclusion, with the ability to attach to both kinds of cells and the ability of blocking the production of IFN due to different kind of factors, these pathogenic factors are what make H7N9 a possible pandemic disease especially so with the easy spreading of the virus within the host body.


  1. Zeng.H, Belser.J (2015). A(H7N9) virus results in early induction of proinflammatory cytokine responses in both human lung epithelial and endothelial cells and shows increased human adaption compared with avian H5N1 virus. Journal of Virology11th February, retrieved 4th February from <
  2. Arilahti. V, Mäkelä. Sanna.M, Tynell.J, Julkunen. I,   Österlund.P          (2014). Novel Avian Influenza A (H7N9) Virus Induces Impaired Interferon Responses in Human Dendritic Cells. PLOS, 7th May, retrieved 4th February from <;

Evolution of H7N9

In the past few articles, we have been seeing summaries of articles that states the increase in the number of cases of H7N9 flu virus at different areas, however, we have never really discuss about the start of H7N9 flu virus. Here, we will have an overview of evolution of H7N9 virus.

Report has shown that the H7N9 virus have actually been evolved from four other kind of flu viruses which ranges from wild birds to domestic chickens. This kind of re assortments have also been known to be common among the spread and the evolution of influenza viruses as stated in another article “The Scientist, an article titled “Evolution of H7N9, September 20, 2013.” “. In the same article, is also states that after going through the complete sequencing of H7N9 and H9N2, it acts a marker that the H7N9 virus has actually been a mixture of other kind of virus strains. Will this be a pandemic strain in future, this is a question that has not answer yet.

The random re assortment that H7N9 has undergone shows that it has gotten its hemagglutinin gene has been from domestic ducks, neuramidase gene has been from wild birds and the rest of the gene has been from domestic poultry.

In conclusion,  with all these random assortment in place, with the multiple H arm and the N arm that are present as well as with the different genes that are present in the virus itself,  this  can cause the rise in many different kind of influenza viruses.


  1. Weeks.E(2013). Evolution of H7N9, The Scientist, 20th September, retrieved 29th January from <;
  2. Gray.R(2013). Doctors warned to look out for new H7N9 bird flu virus, The Telegraph, 1st May, retrieved 29th January from <;
  3. Genetic Evolution of H7N9 Virus in China, 2013, CDC,(n.d) retrieved on 29th January from <;

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3rd and 4th imported case in Hong Kong

On 5th January 2017, the 3rd case of imported human H7N9 avian flu was reported  in Hong Kong. This case involves a 62 year old man being infected after being said to have visited Zengcheng, Guangzhou. He have discharged himself from the hospital even though it was against the advice from the doctors. After travelling back to Hong Kong on 3rd Jan, he was hospitalised on the same day and on 5th Jan, his condition worsened and has been transferred to the  intensive care unit. This is the 3rd case being reported in Hong Kong throughout this season.

Earlier this morning (11th Jan 2017), a 10 year old boy has been reported to have contracted  H7N9. According to the article, it shows that  the boy and his family have been travelling to Foshan, Guangdong province to visit on of their family members there who have kept a few live chickens. They denied any kind of contact with the chickens even when they visited a market as they did not visit the poultry section in the market.  He has been known for good health conditions and have developed conditions like fever, cough and have vomited after returning from the trip. When he was admitted in the hospital, his condition stablised but after he was discharged, on the same day, he was reported to have been isolated and re admitted into the hospital. This marks the 4th imported human case in Hong Kong in this season.

For the past few blog post, we have seen the updates on this virus in different areas around the world, in the next blog post, we will look into the evolution of H7N9 virus.


  1. News Desk(2017), Hong Kong reports 3rd imported human H7N9 avian flu case
    ,Outbreak News Today, 5 January,  retrieved on 11th January 2017 from < >
  2.  Mok.D(2017), Hong Kong boy, 10, tests positive for H7 avian flu virus after visit to mainland China, South China Morning Post, 11th January, retrieved on 11th January 2017 from < >

On 30th December…

On 30th December 2016, it is been reported that in Shanghai and Hong Kong, there is a case of H7N9 each.  This is the second case that happened in Hong Kong, the first resulting in the death of an elderly man. The patient in Shanghai is being treated in the hospital.

Through the article, it is known that a 70 year old man had been tested positive for the H7N9 strain of the virus and prior to that, “the man had come across mobile stalls selling live poultry in Zhongshan“, however, is this the source of infection? The authorities are still investigating on this issue. This patient is then being hospitalised and anyone that has been in close contact with this patient is being placed under medical surveillance.

The H7N9 virus has caused the death of an elderly man who had bought a chicken in Guangdong province. He died less than a week after being tested positive for the virus.

Hong Kong is particularly alert to the spread of this virus as it brought back the history of bird flu being reported in humans in Hong Kong first where it caused the death of 6 people and subsequently  hundreds more subcummed to the bird flu worldwide.


  1. Our Foreign Staff(2016), Shanghai and Hong Kong confirm new human cases of H7N9 bird flu, The Telegraph, 30 December,  retrieved on 8th January 2017 from < >

As stated in an Article on 22 December

As stated in an article on 22 December, it states that avian influenza have been detected in poultry in parts of Europe, Asia and North America. 6 cases of avian flu has been reported in Macau and mainland China.

The article has listed a few cases that has been happening around in China, Jiangsu province, Fujian, Guangdong and Macau. Most of the cases were men and that their symptoms have only developed from 6-20 November. Even though avian influenza virus is most commonly spread from poultry to human, out of those being infected, one did not have any contact to any kind of live poultry. There is an increase in the control and surveillance efforts in the affected regions and patients have been provided with enhanced medical care.There is also an increase in the survillence in poultry markets and infection education have been made.

These cases brought the total number of cases to a total of 807 worldwide since early 2013. Even though sustained human transmission is unlikely with the H7N9 virus, officials expect to see additional human cases.


  1. KEET.E(2016), China Reports Six Human Cases of H7N9 Avian Influenza, ContagionLive , 22 December, retrieved on 29th December 2016 from <;

H7N9 case on 19th December

In a recent article on 19th December on Outbreak News Today, it shows that there is a “first imported human case of H7N9 in Hong Kong this winter”. The patient did not confirm that he came into contact with poultry or wet market at first. However  in the subsequent test especially when testing on the nasopharyngeal sample, it tested positive for the H7N9 virus even though at first, it showed negative. This is the very first case of H7N9 in Hong Kong during this winter season.

Also in Guangdong, it has also reported the first human case of H7N9 case this year winter. Other than H7N9, H5N6 cases were being reported as well which could be found in the feces of birds. Research has also shown that especially during winter, there would be an increase of avian influenza viruses.

The article concludes by informing the reader on the precaution that they should take for example, avoiding any kind of contact with poultry and also a reminder that if the personnel is sick after coming into contact with poultry, they should seek the doctor’s consultation as soon as possible.


  1. News Desk (2016). Hong Kong: Imported human case of H7N9 avian influenza reported ,Outbreak News Today, 19th December, retrieved on 25th December 2016 from <;

Outbreak of H7N9 (13th Dec)

In a news article in Outbreak News Today, it states that there is an increase in the number of H7N9 avian flu in mainland China. The cases being reported shows that out of the 5 patients, 4 patients had contact with poultry markets and all 5 of them are in serious conditions.

In the article, it restated that the main form of transmission is through chickens and ducks or in general, poultry. Clinical symptoms also include conjunctivitis, flu-like symptoms or chest irritation. In serious conditions, it may cause failure to the respiratory system, organs and the worst case resulting in death.

It also states that the easiest way of transmission is when in contact with infected poultry and that human to human transmission is still rare. However, elderly, young  children and people with chronic illness may develop complications that may add on to contracting avian flu.


  1. H7N9 avian influenza: More cases reported on mainland China(2016), Outbreak News Today (13th December), retrieved 22th December from <;

What can childhood infection protect us against?

A recent article titled: “Childhood infections provide lifelong protection against flu viruses that come from animals” was published on the 10th of November 2016 on UCLA classroom < >. Here is the summary of what the article have to say about the relation between birth year and the virus.

The article focused more on H5N1 and H7N9 viruses where each have affected more than 1400 people in total. It has been shown that it was because of the influenza that might be present during or around the timing that we were born that gives us the build up of immunity to the kind of virus that might be around when we were born. If this happens when we are a child, this can be called ” childhood imprinting”. This imprinting will be able to allow the person to not get affected or they will have a reduced risk of severe disease, reduced chance of getting sick and also reduced chance of contracting H7N5 or H5N1 viruses.

The relationship between the birth year and the kind of immunity that the body will produce has lead the researchers to may be able to predict the kind of virus strains and the age as well as the potential of  virus from a group of people that might spread to the community.


  1. Wolpert.S(2016) Childhood infections provide lifelong protection against flu viruses that come from animals,  UCLA newsroom 10th November, retrieved on 14th November from   < >

New lab test found!

This will be a summary of a News article that has been published pertaining a discovery of a  new lab test to detect avian flu virus.

Research has shown that there is a new way to detect bird flu virus!

Some strains of the avian bird flu disease are deadly to humans for example the H7N9 strain! The study conducted in India has shown that the virus can be detected from samples in the wild and also from water bodies. (this gives us more information on where the strain might have come from and which form of origin it came from.)

The experiments were being used to test the concentration of the virus from the various water bodies ranging from fresh water specimens to salt sea water. Even though this method has not been fully known to the public yet, this new method of testing is known to be “novel, sensitive, user-friendly and cost-effective method” as compared to the past method of testing of water bodies which might be infected with the avian flu virus. As stated in the first post, this strain of avian flu can be transmitted from poultry to human, in this study especially, it was tested that water is one of the main way of transmission and that is one of the method that the strain will be able to be retained and kept alive for a long time. Thus with the use of this new method, avian flu found in water bodies can be detected much easily and this will contain the spread of the disease.


  1. Saxena. A(2016) New Lab Test to detect bird flu virus on anvil, Daily News and Analysis, 25th October, retrieved on 28th October from <;

Introduction to H7N9

To most of us,  the term “Avian Flu”/”Bird Flu” might not be unfamiliar, however, how many of us DO know about H7N9?Throughout this entire time span of blogging, we will be tracking the Human infection with avian influenza(H7N9)virus.

Now, a brief introduction to the avian influenza ,H7N9 virus.

The first case of H7N9 virus being reported happened in China 2013, and from then on, there were 132 cases being reported alone in Spring, specifically in March/April. Despite the number of cases, it is still rare for the transmission to be from human to human!. (Avian Influenza A (H7N9) Virus(2014).CDC Centers for Disease control and Prevention, 12th February, retrieved 23rd October from <  >)

What IS avian influenza H7N9? (Avian influenza A(H7N9) virus(n.d)World Health Organisation, retrieved 23rd October from < >)

  1.  it is a sub type of influenza that has been detected in birds/poultry.
  2.  this disease causes much attention as it causes the affected humans to be severely ill!
  3. The mode of transmission is  usually through the bird-human interaction as the cases being reported has been seen as the human has been exposed to infection in the environment or coming into contact with infected poultry.

What are the sign and symptoms you may ask?

It ranges from common cough and cold signs like fever, cough, sore throat to pneumonia. Given a more serious case of this influenza, it may cause conjunctivitis and even sever respiratory illness.(Avian Influenza A Virus Infections in Humans(2016)CDC Centers for Disease control and Prevention,25th May, retrieved 23rd October from < >)

As the starting symptoms are very similar to common cough and cold, many people tend to overlook these symptoms !Therefore, if you suspect you have avian flu, h7n9 or have been feeling sick after visiting places with Avian Flu outbreak, do visit the doctor.


  1. Avian Influenza A (H7N9) Virus(2014).CDC Centers for Disease control and Prevention, 12th February, retrieved 23rd October from <  >
  2. What IS avian influenza H7N9? (Avian influenza A(H7N9) virus(n.d)World Health Organisation, retrieved 23rd October from <;
  3. Avian Influenza A Virus Infections in Humans(2016)CDC Centers for Disease control and Prevention,25th May, retrieved 23rd October from < >