Hong Kong influenza|Forgotten pandemic Flu|Moa pandemic Flu

Hong Kong influenza|Forgotten pandemic Flu|Moa pandemic Flu

The Hong Kong influenza was a pandemic that affected the world from 13 July 1968 in British Hong Kong, killing about 3million people around the world.

Causes of Hong Kong influenza

              It's a pandemic (disease spreads rapidly across a country or the world), it is an infectious disease and seasonal flu mainly affects the respiratory system.

              Caused by novel influenza A subtypes viruses which belong to the RNA, orthomyxoviridia family.

              Hong Kong influenza was highly contiguous as it spread fast, starting from Southeast Asia to the world including Australia, Africa, Europe, and South America.

              It was caused by an H3N2 strain of the influenza virus.

              It was the first known outbreak of the H3N2 strain.

              But in the late 19th century there was evidence of H3N1 infections serologically.

              H3N2 was descended from the strain H2N2 which affected the world 1957 - 1958 and caused Asian flu, sharing it in internal genes and neuraminidase, and becoming established as predominant circulating influenza A-Type.

              1918(Spanish influenza caused by H1N1AND and transmitted from birds to humans ) then occurred mutation to virus and in 1957(Asian influenza caused by H2N2 viruses which formed from reassortment between H2N2 avian virus and H2N2 human virus) after this in 1968 occurred Hong Kong influenza which caused by H3N2 virus which formed due to reassortment of H3 avian virus and H2N2 human virus).

              Occurred antigens shift and genetic process as genes of different subtypes were reassorted and formed the new one.

              Queen Mary hospitAl isolated the virus.

              The strain H2N2 and H3N2 contain genes from avian influenza viruses.

              It reached us through troops then in October 1968 returning to California from Vietnam.

Virus formation

              The H3N2 subtype has two types of proteins on its surface.

              Proteins called hemagglutinin and neuraminidase were formed because of an antigenic shift or gene reassortment of different strains.

              Viruses had genes from birds, human and pig influenza Astral.

Outbreaks and origin

              The first appearance of Hong Kong influenza was recorded on 13 July 1968 in British Hong kong.

              There was unconfirmed information that told us the actual outbreak started in mainland China before spreading to Hong Kong.

              The population density in Hong Kong was more than 6000 people /km; this helped in the spreading of the virus,  and the outbreak lasted about six weeks.

              The affected population was about 500.000 people (about 15%).

              According to other types of flu it is considered to be mild as Spanish influenza killed about 50 million around the world.

              Clinical signs were mild.

              The death rate was low, was below.5  making it a category 2 disease in the pandemic severity index as the people had some immunity against the N2 flu virus due to exposure to Asian flu strains in 1957.

              In China, there were two waves of influenza mainly in mainland China, One of them was between July to September in 1968, The other one was between June and December in 1970.

              Affected many areas of China.

              It killed about 30.000 deaths in the UK half of them under 65 years old.

              In other areas as Vietnam and Singapore, the Hong Kong influenza was reported.

              It killed about one to four million around the world, as reported by the World Health Organization and Encyclopaedia Britannica.

              It was reported as corners were stored in Berlin underground tunnels and bin men were recruited to bury bodies due to undertaker shortages across West Germany.

Transmission of Hong Kong influenza

              The virus spread from human to human in the population.

              It is transmitted through the air by coughs or sneezes in mammals and creates aerosols containing viruses.

              Healthy people can be affected by direct methods from aerosols or indirectly by touching eyes, nose, or mouth. 

              The influenza virus possesses a viral surface protein which is called hemagglutinin HA which affects people who suffer from a lack of immunity.

              Also said Hong Kong influenza can be transmitted by gastrointestinal, blood route and sexual as a person may be affected by contaminated food, transfusion of affected blood, or sexual contact with the affected person.

               it was a fetal when it affected pregnant women.

              The main intermediate hosts were swine and other species of birds.

Symptoms of Hong Kong influenza :

              Like other types of influenza it lasted for four or six days but in some cases may be more than two weeks.

              The first peak was in winter during the school holidays.

              Signs were common as cold so people disregarded it until it became worse.

              Signs started with a runny nose, congestion of the upper respiratory system.

              Headache in front of the head and eyes caused discomfort in the eye.

              On the second day, there was a fever.

              After that virus invaded the bloodstream it affected the respiratory system. Invasion of the virus to muscle, causing an inability to move muscles.

              Severe muscle pain is caused due to the Affected upper tract of the lung and causes a non-productive, dry cough with white sputum and a sore throat.

              May cause diarrhea, vomiting, and nausea, loss of appetite, and feel weak.

              In general, there was fatigue and Weakness.

              It caused severe complications as

1- Renal failure.

2- Increase liver enzymes.

3- Pneumonia.

4- gastrointestinal manifestations.

5- asthma.

6- chronic obstructive pulmonary disease( COPD ).

7- fetal developmental problems during pregnancy.

The immune system against Influenza virus :

              First, body temperature increases trying to kill the virus.

              Due to increased temperature episodes of shaking chills appear.

              Relief doesn't come quickly and symptoms remain for 72 hours

              You need about 3:5 days to feel well.

Treatment :

              Rest in bed to relieve symptoms.

              Aspirin and paracetamol may relieve them.

              Sufficient amounts of warm fluids are good.

              Some doctors give antiviral drugs as oseltamivir or zanamivir.

Vaccination :

              The vaccine was developed rapidly due to its peak in school holidays. 

              The vaccine wasn't widely available.

              Flu vaccines are based on predicting which mutants of H1N1, H3N2, H1N1AND influenza B proliferate every season.

              Past vaccines of influenza didn't contain H3N2 strain so the vaccination with last year's seasonal vaccine wouldn't be expected to protect H3N2 Perth-like strain.