Information about non-seasonal Influenza-A H1N1 2009 in New Zealand - Swine flu facts

Don't Panic..stress weakens your immunity to the flu...

What is the 'Flu? Symptoms of Swine Flu; similarity to 1918 H1N1 Spanish Flu How is Swine Flu spread? Why face masks may NOT be that helpful Treatment for Swine Flu and updates on Tamiflu resistance What is being done to control the spread of Swine Flu? School pandemic plans - school compliance with regard to NAG5 and Health and Safety Act 1992 Latest global Swine Flu stories from NZ and world-wide

by Medical Microbiologist / Teacher Michael Fenton

(Microsoft Innovative Teacher, Ministry of Education eLearning Fellow)

What is the 'Flu? The illness commonly referred to as the 'flu is more properly called influenza. Influenza is a viral infection of the lungs characterised by fever, cough, and severe muscle aches. In the elderly and infirm, it is a major cause of disability and death (often as a result of secondary infection of the lungs by bacteria). Influenza is not a case of low fever and sniffles that keeps you home in bed for a day , or a gastrointestinal upset ("stomach flu")

True influenza is an acute infectious disease caused by a member of the orthomyxovirus family. This electron micrograph (courtesy of Dr. K. G. Murti) shows several influenza virus particles at a magnification of about 284,000 times. In general, to give an idea of scale, the host cell that will be the target of the virus is about 500 times bigger than the virus itself...

Some strains of influenza A seen in the past:

1918	H1N1	Spanish flu
1957	H2N2	Asian flu
1968	H3N2	Hong Kong flu
1976	H1N1	Swine flu

Non-seasonal Influenza A (H1N1) 2009, aka Mexican Swine Flu;

According the Centre for Disease Control (CDC) Swine Influenza (swine flu) is a respiratory disease of pigs caused by type A influenza that regularly cause outbreaks of influenza among pigs.

Swine flu viruses do not normally infect humans, however, human infections with swine flu do occur, and cases of human-to-human spread of swine flu viruses has been documented.

An influenza pandemic occurs when a new strain of influenza virus emerges, spreading around the world and infecting many people at once.

The World Health Organisation (WHO) has declared that a pandemic situation exists and individual countries must take responsiblity for managing outbreaks of non-seasonal influenza (H1N1 swine flu).

NEW DEVELOPMENTS:The severity of illness and spread of the virus is difficult to predict. As of July 4th 2009, new research and data indicate some early assumptions that this virus will cause only a mild flu may have been a little optimistic.

 

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What are the symptoms of Swine Flu in Humans? fever cough sore throat muscle aches  eye infections pneumonia Spread The virus is spread person to person via small particle aerosols (less than 10μm) which can get into respiratory tract. It can also survive for a short time on surfaces and can be spread by this route if the virus is introduced into the nasal mucosa before it loses infectivity. The incubation period is short, about 18 to 72 hours. Site of infection Influenza virus infects the epithelial cells of the respiratory tract. The cells die, in part due to the direct effects of the virus on the cell, and also possibly due to the effects of interferon. There is reduced clearance of infectious agents from the respiratory tract. Gaps in the protective epithelium provide other pathogens with access to other cells (secondary infection results). NEW DEVELOPMENTS: In a study led by Yoshihiro Kawaoka of the University of Wisconsin, the novel H1N1 (swine) influenza shows some resemblance to the virus strain that caused the 1918 flu pandemic, with a greater ability to infect the lungs than common seasonal flu viruses. The information supplied to the public often claims that Swine Flu results in moderate illness but Kawaoka said that does not mean it is like seasonal flu. While media reports often compare the new virus to seasonal flu, this H1N1 strain is more accurately described as a 'distant cousin' to seasonal flu. "There is a misunderstanding about this virus," he said in a statement. "There is clear evidence the virus is different than seasonal influenza." The new Swine Flu strain can spread beyond the upper respiratory tract to go deep into the lungs -- making it more likely to cause pneumonia, the international team said. Other studies in recent weeks support these findings

 

Do face masks filter out swine flu viruses?

Normal face masks are NO GOOD at preventing Swine Flu viruses from passing through.

In the local paper (Taranaki Daily News) was a report that a pharmacy was running out of face masks, such was the demand by the public.

The bad news is that the pore size (size of the 'holes' in the material used to make the masks) is very large compared to the Swine Flu virion.

So what kind of masks SHOULD you be using? The CDC suggests that masks rated N95 or higher be used. The '95' rating means that the mask will stop 95% of particles that are 0.3 micrometers or larger in size. In comparison, large aerosol droplets in the air containing flu virus are about 0.5 micrometers in size, too big to pass through the N95 mask but way too small to be blocked by the masks sold in hardware stores or pharmacies. N95 masks are also form fitting to the face for a snug, tight fit. They are also expensive and in limited supply.

What cheap face masks ARE good for is to prevent spit and sneezes from spraying surfaces or people nearby. Wearing a paper or cloth mask may also make the person feel better psychologically. These masks should be disposed of after a single use followed by thorough hand washing (see the advice below from Dr Peters).

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Treatments for Swine Flu

Viruses are not living therefore they cannot be killed. For this reason anitbiotics cannot be used* to kill influenza viruses. If viruses are not alive, how does one virus in your body become millions? Your own cells, once infected by a virus, are 'tricked' into producing more virus particles.

* [I said that antibiotics are of absolutely no value against the flu virus. However, they are often given to patients to combat the secondary bacterial infections that occur and that are usually the main cause of serious illness and death. ]

If you can not kill the virus, the two main strategies used include:

Immunisation

Drugs

Reye's syndrome is rare, but approximately 40% of cases are fatal. The effects on the liver and brain are particularly serious. The origin of Reye's syndrome is unclear but seems to follow certain viral infections such as influenza or chicken pox (varicella zoster/herpes zoster), especially if they are in the young and especially if they have been treated with aspirin. Aspirin is contraindicated for childhood or adolescent fevers because it is a risk factor in the development Reye's syndrome. Acetaminophen and Ibuprofen are apparently not associated with Reye's syndrome. Recent media reports in New Zealand about using Bonjela reflected findings that salicylate salts are not recommended for children under 16.

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Controlling the spread of Swine Flu

The World Health Organization (WHO) maintains constant surveillance of influenza outbreaks world wide and has a series of 'sentinel' labs to look at what is happening in the circulating virus population.

The New Zealand Ministry of Health (MoH) is in contact with the Centre for Disease Control (CDC) and the World Health Organisation (WHO). Dr Julia Peters Clinical Director of ARPHS suggests stay at home and away from others if you are sick cover your coughs and sneezes with a tissue put used tissues into a rubbish bin avoid touching your eyes, nose or mouth – germs spread that way be careful to wash hands often with soap and dry them thoroughly – hand hygiene is critical: even when you start to feel better there is still a risk of infecting others, so keep to the 20/20 rule – 20 seconds washing and 20 seconds drying keep surfaces clean at home, school and work. A couple of extra suggestions: Eat healthily - good nutrition is essential to maintaining your immune system. Relax and do not worry too much - stress is not good for the immune system either!