Swine flu – the facts

by Domenica Goduto and Kirstyn Smith

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photo courtesy of typepad

What is swine flu?Swine flu is a respiratory disease which infects pigs, a new strain of the H1N1 influenza virus which is also derived in part by the human influenza virus Type A.  Most outbreaks occur in late autumn and winter on farms, killing between 1% and 4% of animals it infects.  The virus is a mixture of pig, human and avian flus.  The WHO has confirmed that the cases examined are a never-before-seen version of the virus.

Can humans catch it?

While swine flu is not usually found in humans,  the disease can be contracted in two ways.  The virus can be contracted after being in contact with infected pigs, or being in areas in which infected pigs have been kept.  It can also be spread person-to-person in the same way as seasonal flu – through coughing and sneezing.  The infection cannot be caught by eating pork or pork products.

What are the symptoms?

Swine flu has symptoms similar to those of the more common human seasonal form, including respiratory problems, fatigue, fever and lack of appetite.  In some cases, diarrhoea and vomiting have also been reported.  Seasonal flu is caused by viruses that are adapted to spread in humans, who have some natural immunity to common strains and can boost it by immunisation with a vaccine.

Why is swine flu spreading so quickly?

The World Health Organisation is trying to determine this by collecting data on the current outbreak – as yet

Passengers in Mexico wear face masks
Passengers in Mexico wear face masks

not enough is known about the virus determine why it is so highly transmissible. Epidemiologists need more information in order to assess the risk of a global pandemic, and whether the deaths in Mexico were the result of the same virus which is causing milder symptoms in other countries. Mexico is a popular holiday destination, particularly for North Americans, so it is not surprising that a large number of cases have emerged in the wake of the busy spring break period in March and April as school groups and other travellers return from their holidays.

Can the virus be contained?

The fact that cases of swine flu have already been reported as far away as New Zealand means that it is already too late to completely confine the virus at its point of origin. However, governments around the world are taking measures to slow the spread of the illness. In Mexico, officials have banned such traditional forms of greeting as the handshake or the kiss on the cheek, and many locals have taken to wearing protective masks in public. Church services, football matches, and other large-scale public gatherings have been cancelled or restricted, and museums have been closed. Other countries are screening travellers returning from abroad and isolating those who show signs of sickness. Britain’s chief medical officer, Liam Donaldson, has instructed hospitals to be on the look-out for the virus, with special instructions issued concerning possible symptoms and the tests to be performed. It is expected that the government’s £500 million pound stockpile of the tamiflu vaccine will be sufficient to treat any confirmed cases and prevent the illness from spreading among hospital staff and the public.

What treatments are available?

The US authorities have confirmed two drugs which are believed to be most effective in preventing initial symptoms from getting worse: a pill called Tamiflu and an inhaler called Relenza.  However, they also maintain that it is unclear how effective currently available flu vaccines would be at offering protection against the new strain, as it is genetically distinct from other strains.  Scientists in America are developing a bespoke new vaccine designed to combat the new strain of swine flu.  It is feared that it may take some some to perfect and that suppliers may not be able to deal with the huge demand that will be generated.

Nevertheless,  health secretary Alan Johnson says the Britain has £500 million of flu drugs ready, adding:  “Once we know what the strain is we will look to find a vaccine to prevent it and we have a pre-agreement for these vaccines to be produced as soon as we decide.”   

Past cases

In 1976 200 people were left seriously ill and one person was killed by an outbreak of swine flu in New Jersey.  The virus circulated for about a month and then disappered.  In 1988 in Wisconsin, a pregnant lady contracted the disease while in hospital and died soon afterwards.  Between 2005 and 2009, there were 12 human cases of swine flu in American, none of which were fatal. 

Other global pandemics

In 1918, the Spanish flu pandemic infected up to 40% of the world’s population.  More than 50 million people died, mainly young adults.  The H1N1 strain of flu was responsible and this remains the most devastating outbreak of modern times.

In 1957, Asian flu, a human form of the H2N2 virus combined with a mutating strain found in wild ducks, killed 2 million people, with the elderly being the most vulnerable.  However, due to fast action by health authorities, who regonised the strain and rapidly made vaccines available, the impact of the pandemic was minimised.

In 1968, a strain of H3N2, first detected ni Hong Kong, killed up to 1 milion people world wide.