All about Swine Flu (H1N1)

H1N1 flu, also called swine flu, is a respiratory disease of pigs that has now spread to humans. “Swine” refers to animals such as pigs, hogs, and boars. “Flu” is an abbreviation of influenza. “H1N1” is the name of the virus that has spread to humans.


The Origin

People do not normally get swine flu viruses, but human infections can and do happen. The Swine Flu outbreak is attributed to manure lagoons of La Gloria of Mexico. 
The facility, Granjas Carroll de Mexico, is partly owned by Smithfield Foods, a Virginia-based US company and the world’s largest producer and processor of pork products. Residents of La Gloria have long complained about the clouds of flies that are drawn the so-called “manure lagoons” created by such mega-farms, known in the agriculture business as Confined Animal Feeding Operations (CAFOs). Then the disease was spread to Mexico City then to the world. 

The disease progressed to a national emergency in Mexico and the whole country was shut down for five days in May 2009. The Mexican move was widely praised by the international community to control the disease in the country. However modern living of humans facilitated the spread of virus through out the world by July 2009. 

How virus jumped from Swine to Humans?

The virus currently infecting humans is a form of a swine flu virus and not the actual one.
It has jumped from pigs to humans and contains genes from pig, bird and human flu viruses.
A more appropriate name would be swine-origin flu and not swine flu.
The Lethal Leap 
Every virus has 8 genes 

Strains of flu viruses jump from one species to another without the 8 genes changing (no genetic change) or with a reassortment of the 8 genes (antigenic shift).
An example of reassortment is 

a) a duck passes a bird flu virus to a pig 
b) a person passes a human flu virus to the same pig 
c) if the viruses infect the same cell in the pig, the genes from the bird strain can mix with the genes from the human strain to form a new virus in the pig. This can also occur in a human or chicken infected with different strains.

The Viruses 

Click on the picture to enlarge it.

Viruses are very small living particles. This section reviews information about viruses that will help you understand the H1N1 flu virus.

Viruses are made of an outer shell that protects genetic material packaged inside. In order for a virus to reproduce, it needs to enter a living cell by attaching itself to the living cell’s surface. Viruses tend to infect only specific cells in a specific species. For example, certain viruses may only attack human cells while others can attack only bird cells.  Once inside the cell, the genetic material of the virus blends with the genetic material of the infected cell and copies itself hundreds, if not thousands of times.

The hundreds of copied viruses then kill the cell, burst out of it, and infect many new cells. The cycle repeats itself and can make a person very sick unless the person’s immune system destroys the virus. The immune system is responsible for defending the body against viruses.

When a virus is copying itself, the genetic material of the virus can go through changes known as ‘mutations’. The virus can also exchange genetic material with the infected cell which can modify the surface of the virus. This may make it possible for the virus to attack the living cells of different species such as pigs and humans. A virus modified by mutation is known as a different strain. Type A Type B & C
There are three types of influenza viruses, A, B and C. Types B and C are usually only found in humans. Type A can be found in both humans and animals such as birds, pigs, horses, whales, and seals.

There are three main types of influenza virus: type A, type B and type C. Type A can be found in both humans and animals such as birds, pigs, horses, whales, and seals.  It is responsible for regular outbreaks of disease in humans. This virus also infects pigs, horses and other animals and its natural host is the wild bird. In fact, only type A can infect birds. Type B viruses also cause human infection, but mutate slowly and are less common. Influenza type C causes only mild respiratory symptoms and has not been linked to serious human epidemics.

Influenza A is further classified by the nature of some of the proteins that are embedded in its outer layer. Haemagglutinin (H) and neuraminidase (N) are two proteins with important roles in how effectively the virus can invade a host. Influenza A can have a number of different types of haemagglutinin but for human infections, H1, H2 and H3 are important. There are also a number of different neuraminidases, of which N1 or N2 are usually found in combination with one of the above H molecules.

Viruses are named after which complement of H and N are in their outer layer. For example, swine flu is a new H1N1 virus and therefore carries the proteins haemagglutinin 1 and neuraminidase 1. Although other H1N1 viruses have circulated before, this new strain differs substantially from previous strains.

Swine flu is a new H1N1 virus. This means that before this year’s outbreak, this exact type of virus has never before circulated in humans. This is of concern at it means that the general population is not immune to the virus, and so it has the potential for a greater impact than ordinary seasonal influenza.

H1N1 viruses are fairly uncommon and every year H1N1 adds to the burden of disease associated with seasonal influenza. However, viruses change regularly, creating new strains. Even small differences in viral structure can affect the way a host responds to an infection. This is why flu vaccines need to be updated every year to keep up with these changes. Viruses change by mutating in several different ways. Sometimes spontaneous mutations can happen in the genes of a virus. Alternatively, a process called reassortment can occur, when different strains of flu virus share genes with each other in the same host to make a new strain.

What will the impact of swine flu be?

It is difficult to predict the impact of swine flu. So far, most infected people recover after a period of illness that is similar to seasonal flu. However, in people with comorbidities (e.g. lung disease, heart disease, kidney disease and diabetes) or the elderly and very young, the infection can be more severe.

To ensure that services can cope with future demand, scientists work hard to predict how the virus may spread and how it will affect people. 

What are the symptoms of Swine Flu (H1N1)

The most common symptoms of H1N1 influenza in humans are similar to typical human flu and include:
• Fever
• Cough
• Sore throat
• Body aches
• Chills
• Fatigue

Some people have reported diarrhea and vomiting associated with H1N1 flu. People who have chronic conditions such as asthma, diabetes, congestive heart failure, etc. may notice a worsening of their medical conditions.

There are antiviral medicines you can take to prevent or treat swine flu. There is no vaccine available right now to protect against swine flu. You can help prevent the spread of germs that cause respiratory illnesses like influenza by Covering your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.

Washing your hands often with soap and water, especially after you cough or sneeze.
 You can also use alcohol-based hand cleaners.
Avoiding touching your eyes, nose or mouth. Germs spread this way. 
Trying to avoid close contact with sick people.
Staying home from work or school if you are sick.
When you have to go out into the Swine Flu infected area, do not forget to use mask. When you are back home, properly dispose off the mask and wash your hands properly.  Preferably, you can take a hot water bath. You should also gargle your throat so that it should be kept clean. Otherwise any normal throat infection also causes mental worry. 

Emergency Signs

If you have severe symptoms, your doctor can test if your flu symptoms are caused by H1N1 flu. 

You should watch for flu-like signs. These signs are fever, body aches, runny nose, sore throat, nausea, vomiting, and diarrhea.
Signs of the flu are often mild and do not require medical evaluation in the clinic. When the symptoms are mild, it is important to keep yourself hydrated, get plenty of rest, and practice good hand hygiene.

You should seek medical care if you or child develop any of the “emergency warning signs”. Some of the “emergency warning signs” that require urgent medical attention are listed next.

In children, some emergency warning signs include:
• Fast breathing or trouble breathing
• Bluish skin color
• Not drinking enough fluids
• High or prolonged fever

You should also seek immediate medical attention if you notice changes in your child’s mental status, such as:
• Not waking up
• Not interacting
• Extreme irritability and not wanting to be held

In adults, some emergency warning signs that need urgent medical attention include:
• Difficulty breathing or shortness of breath
• Pain or pressure in the chest or abdomen
• Sudden dizziness
• Near-fainting or fainting
• Confusion
• Severe or persistent vomiting
• High or prolonged fever

If you or your child have flu-like symptoms that get better but then come back with a fever and a worse cough, seek medical attention as soon as possible. 

How long can influenza virus remain viable on objects (such as books and doorknobs)? 

Studies have shown that influenza virus can survive on environmental surfaces and can infect a person for up to 2-8 hours after being deposited on the surface. 

Germs can be spread when a person touches something that is contaminated with germs and then touches his or her eyes, nose, or mouth. Droplets from a cough or sneeze of an infected person move through the air. Germs can be spread when a person touches respiratory droplets from another person on a surface like a desk, for example, and then touches his own eyes, mouth or nose before washing hands. 


Antiviral drugs approved for human influenza viruses should work in treating H1N1 influenza infection in humans. However, there are no known medications that treat H1N1 influenza infection specifically.

Antiviral drugs are prescription medications that can help the flu by keeping flu viruses from reproducing in your body. These include pills, liquids, or inhalers.

Antiviral medications are currently recommended only for those patients with moderate or severe illness from H1N1 flu. Most people get better without antiviral medicines.

Antiviral medications must be taken within 48 hours after symptoms appear. They may diminish your symptoms, but they may not make your symptoms go away entirely.

If supplies of antiviral medications are limited, it is necessary to save them for people who may develop the most severe symptoms. Other flu treatments that should work for H1N1 flu include rest, medications to bring down a high fever, and drinking plenty of water.
If complications happen and you become very sick, hospitalization may be needed. Hospitalized patients may be given oxygen or use a respirator.

Children or teenagers with the flu should get plenty of rest and drink lots of liquids. The medicines that they take to relieve their symptoms should NOT contain aspirin. Never give aspirin to children or teenagers who have flu-like symptoms, especially a fever, without first speaking to your healthcare provider. Giving aspirin to children and teenagers who have influenza can cause a rare but serious illness called Reye syndrome. Reye syndrome involves brain damage and liver damage. Its causes are unknown but it is associated with the use of aspirin in children to treat influenza and chickenpox.

Why we need to take plenty of water?  This will give an opportunity to excrete the viruses in urine. 


TAMIFLU (oseltamivir phosphate) is a drug so far most effective for H1N1 infections. The drug is available as capsules containing 30 mg, 45 mg, or 75 mg oseltamivir for oral use,  in the form of oseltamivir phosphate, and as a powder for 10 oral suspension, which when constituted with water as directed contains 12 mg/mL 11 oseltamivir base.

The starting material of the Tamiflu production process, shikimic acid, is extracted from the star anise seeds. Anise is grown in four mountain provinces in the south west of China (Guanxi, Sichuan, Yunnan und Guizhou).  Since the production of this plant material is limited, so the production of Tamiflu drug. That is why the drug is in short supply and only governments procure and stockfile it. 

Tamiflu blocks the action of the N protein of the H1N1 virus so that virus can't spread. It does not prevent infection, but limits its impact. It must be taken quickly as the virus reproduces most rapidly between 24 and 72 hours after illness begins.  Patients should be instructed to begin treatment with TAMIFLU as soon as possible from the first appearance of flu symptoms. Similarly, prevention should begin as soon as possible after exposure, at the recommendation of a physician. Patients should be instructed to take any missed doses as soon as they remember, except if it is near the next scheduled dose (within 2 hours), and then continue to take Tamiflu at the usual times.

The detailed information on Tamiflu please download the attachment  at the bottom of this page. 

Prevention Tips

Only Vaccine can be foolproof preventive  measure.  But there currently is no vaccine to protect humans against the H1N1 flu virus. The following tips will help you prevent flu infections such as the common flu and the H1N1 flu.

Wash your hands often with soap and water, especially before eating and after sneezing or coughing.

You can also use an alcohol gel product available over the counter, which is also effective in protecting against flu.

When you cough or sneeze, cover your mouth and nose with your elbow or sleeve. Or use a tissue and be sure to throw away the tissue after use. Wash your hands after you sneeze or cough.

Try to avoid close contact with sick people. Avoid touching your eyes, nose, or mouth. Germs spread this way. Try to stay in good general health. Get plenty of sleep, be physically active, manage your stress, drink plenty of fluids, and eat nutritious food.

If you get sick with the flu, here are some tips to avoid spreading the disease to others:

• Stay at home and avoid contact with other people.
• Cover your nose and mouth with a tissue when you cough or sneeze. Put used tissues in a waste basket. If you don’t have a tissue, cough or sneeze into your upper sleeve.
• Wash your hands every time you cough or sneeze. Alcohol-based hand cleaners are also effective.

Do face masks help prevent swine flu infection?

Don't count on those disposable masks to completely protect you against the swine flu percolating around the globe.

Many people in Mexico City, as well as travelers to and from Los Angeles, have been seen wearing mouth and nose protection of one type or another in recent days. 

Most were wearing face masks, which are loose-fitting and designed largely to help stop droplets from spreading from the person wearing the mask. They also protect the wearer's mouth and nose from splashes. They are not created to protect the wearer from breathing in very small particles.

Respirators, on the other hand, are made for just that. They are similar in appearance to the relatively inexpensive face masks but are designed specifically to protect the wearer from breathing in such particles. These masks, known as N95 (filter at least 95% of all particulates that are 3 microns or larger) for its filtering ability, fit more snugly on the face than face masks so that most air is breathed through the filter material. They work best if they are fitted specifically to the person wearing the mask.

A respirator that fits snugly on the face can filter out small particles that can be inhaled around the edges of a face mask. But it's easier to breathe through a face mask than a respirator over a long period of time.  Many people expressed their difficulty to breath through masks and respirators and they say that with masks they would become sick for lack of proper level of Oxygen and also for inhaling the same bad air which was exhaled.

N-95 Mask

The N95 mask was also recommended by the Centre for Disease Control & Prevention (CDC) and World Health Organisation (WHO) as the minimum respiratory protection required for the bird flu virus back in 2003. 

There are two grades of N95 masks, one for industrial use and the other fluid resistant mask for use in hospitals and clinical settings. Both the surgical mask and the N95 respirator offer a physical barrier to contact with contaminated hands and ballistic trajectory particles, such as particles expelled by a sneeze or a cough. 

The N95 mask blocks 95% of particles more than 0.3 microns in size from entering the respiratory system. The problem is, the H1N1 virus is smaller, probably around 0.12 microns in size. Most influenza viruses are of that size, including the recent H5N1 bird flu
virus. This doesn’t mean that masks are of entirely no help, but preventive measures like washing hands regularly may be more important as the virus can be found on hard surfaces. Also, refrain from touching your face, especially mouth and nose, with your hands. Masks should be especially worn by patients, as it helps stop the flu from spreading. Saliva or mucous droplets containing the virus can fly when someone sneezes or coughs.   A wearer would be protected from particles more than 0.3 microns, like saliva and mucous droplets, hydrocarbon or smoke. More importantly, droplets carrying the virus can settle on hard surfaces, on which the virus can survive for 8 hours. So, once again, wash hands and disinfect surfaces.

Who should wear masks

• H1N1 patients

• People with flu-like symptoms

• People going to crowded places, movie halls, hospitals and so on

• People travelling in air-conditioned trains etc

• Doctors, nurses, medical and paramedical staff Mask dos and don’ts 
• Don’t reuse mask; dispose it properly
• Wash your h
ands well with soap or an alcohol-based hand scrub after touching a used mask

• Do not hang it around your neck
• Avoid carrying it in pockets and bags.
N-95 is not the only kind of mask available. If going for some other kind check for: A proper filter; masks with bacterial filtration efficiency (BFE) of 95% are the best (Pic shows Possible entry of virus by wearing the mask loosely-->)

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Domain Admin,
Aug 12, 2009, 4:34 AM