flu & avian flu
FLU
Influenza or "flu" is an infection of the respiratory tract that can affect millions of people every year. It is highly contagious and occurs mainly in the late fall, winter, or early spring. Influenza is spread from person-to-person through mists or sprays of infectious respiratory secretions caused by coughing and sneezing. Influenza affects all age groups and causes moderate to severe illness, loss of school and work, and complications such as pneumonia, hospitalization, and death
Specific about The Virus Influenza
Influenza is caused by a virus called the influenza virus. Viruses are the smallest form of life and, unlike bacteria, can only reproduce in the living cells which they infect. There are three types of influenza viruses, influenza A, B and C. Influenza A can infect humans and other animals while influenza B and C infect humans. Influenza C virus causes a very mild illness and does not cause epidemics.
When viewed through special microscopes called electron microscopes, influenza viruses are shaped like spheres or filaments.
Type A is the most common and usually causes the most serious epidemics
Type B outbreaks also can cause epidemics, but the disease it produces generally is milder than that caused by type A
Type C viruses, on the other hand, never have been connected with a large epidemic
Diagnosis
Usually your physician will make the diagnosis of influenza based on your symptoms and physical examination findings. During epidemics of influenza, this presumptive diagnosis will be very accurate. However, if there is concern about the diagnosis, your physician may wish to perform other tests, for example, a blood count or a chest x-ray
The best way to protect yourself from influenza is to receive an annual influenza immunization. The influenza vaccine is an inactivated (killed) viral vaccine.
To manufacture the vaccine, influenza viruses are grown in chicken eggs, harvested, and then killed through chemical means. The vaccine is then purified and tested for purity, safety, and its ability to stimulate protective antibody in humans.
No vaccine is 100% protective and influenza vaccine is no exception. To a certain extent, the effectiveness of the vaccine in a particular year depends on how well the strains used to make the vaccine "match" the strains that are causing illness. When the match is a good one, the effectiveness can be expected to be higher. Influenza vaccine can prevent symptoms of influenza in 70% to 90% of healthy young adults. However, the vaccine’s effectiveness in preventing influenza may be as low as 30% to 40% in very frail elderly persons. This is because elderly persons have less ability to make protective antibodies. However, even in these elderly and frail people, influenza vaccine has been shown to significantly protect against the severe complications of influenza: hospitalizations and death. So even if the vaccine cannot protect these persons from influenza illness, it may protect them from severe illness and death.
Resting in bed
Drinking plenty of fluids
Taking over-the-counter medicine such as aspirin or acetaminophen (Tylenol, for example)
Do not give aspirin to children and adolescents who have the flu.
Do not take antibiotics to treat the flu because they do not work on viruses. Antibiotics only work against some infections caused by bacteria.
Although the flu vaccine is the best way to prevent getting the flu, three antiviral medicines also are available by prescription that will help prevent flu infection.
. Tamiflu (oseltamivir)
. Flumadine (rimantadine)
. Symmetrel (amantadine)
Tamiflu is for use in adults and teenagers 13 years and older. Rimantadine and amantadine may be used by adults and children who are 1 year of age and older.
These medicines help prevent the flu if you take them for at least 2 weeks during the outbreak of flu in your community
You may use these medicines if you are in close contact with family members or others who have the flu
You may use them if you are in close contact with people who have been vaccinated but whom you want to give added protection from getting the flu
You may use either medicine immediately following flu vaccination during a flu epidemic to protect you during the 2- to 4-week period before antibodies (proteins from your immune system that protect you from the flu virus) develop or when a flu epidemic is caused by virus strains other than those covered by the vaccine
Flumadine and Symmetrel have unpleasant side effects. Your health care provider can help you decide which medicine is best for you. You should discuss the flu vaccine and medicines with your health care provider before the flu season begins.
1. Avoid taking babies or young children into large crowds when the flu is in your area.
2. Avoid close contact, such as kissing and holding, between infants and anyone who has a cold or the flu.
3. Avoid close contact with people who are sick.
4. Wash your hands or use alcohol-based hand sanitizers after being in public or around anyone with a cold or
5. Cover your mouth and nose with a tissue when you cough or sneeze; use a tissue only once and then throw
6. Avoid touching your eyes, nose and mouth.
7. Do not share things that go into the mouth, such as drinking cups, straws, spoons, etc.
8. Clean common surfaces, such as doorknobs, refrigerator handles and phones, frequently if someone in
9. Keep your child home or stay home yourself if you have the flu (fever, muscle aches, cough).
10. Don't smoke around children, and avoid secondhand smoke.
Warning SignsIf your child experiences any of these symptoms, take the child to your pediatrician or to the emergency department right away.
The flu virus adapts quickly to vaccines
By BBC News Online's Ivan Noble
German scientists have discovered a way of targeting the flu virus, which kills thousands of people every year.
A chemical that blocks the way the virus spreads in the body could lead to new ways of treating the illness.
It's very difficult to target influenza because it changes so quickly
Dr Stephan LudwigWürzburg University
Existing anti-flu treatments become ineffective as time goes by because the flu virus is able to mutate rapidly into new strains.
The substance, known as U0126, acts against the influenza A virus, which is responsible for around 65% of flu cases worldwide.
Scientists believe the key to the chemical's effectiveness is the way it deals with flu after the virus has invaded the body's cells.
Dr Stephan Ludwig of the MSZ institute at Würzburg University told BBC News Online: "It's very difficult to target influenza with anti-viral agents or vaccines because it changes so quickly.
"We decided to look at the processes going on within the cell."
Bird flu is an infection caused by avian (bird) influenza (flu) viruses. These flu viruses occur naturally among birds. Wild birds worldwide carry the viruses in their intestines, but usually do not get sick from them. However, bird flu is very contagious among birds and can make some domesticated birds, including chickens, ducks, and turkeys, very sick and kill them.
Bird flu viruses do not usually infect humans, but several cases of human infection with bird flu viruses have occurred since 1997.
How are bird flu viruses different from human flu viruses?
There are many different subtypes of type A flu viruses. These subtypes differ because of certain proteins on the surface of the flu A virus (hemagglutinin [HA] and neuraminidase [NA] proteins). There are 16 different HA subtypes and 9 different NA subtypes of flu A viruses. Many different combinations of HA and NA proteins are possible. Each combination is a different subtype. All subtypes of flu A viruses can be found in birds. However, when we talk about “bird flu” viruses, we are referring to those flu A subtypes that continue to occur mainly in birds. They do not usually infect humans, even though we know they can do so. When we talk about “human flu viruses” we are referring to those subtypes that occur widely in humans. There are only three known subtypes of human flu viruses (H1N1, H1N2, and H3N2); it is likely that some genetic parts of current human flu A viruses came from birds originally. Flu A viruses are constantly changing, and they might adapt over time to infect and spread among humans.
What are the symptoms of bird flu in humans?
Symptoms of bird flu in humans have ranged from typical flu-like symptoms (fever, cough, sore throat and muscle aches) to eye infections, pneumonia, severe respiratory diseases (such as acute respiratory distress), and other severe and life-threatening complications. The symptoms of bird flu may depend on which virus caused the infection.
How does bird flu spread?
Infected birds shed flu virus in their saliva, nasal secretions, and feces. Susceptible birds become infected when they have contact with contaminated excretions or surfaces that are contaminated with excretions. It is believed that most cases of bird flu infection in humans have resulted from contact with infected poultry or contaminated surfaces.
How is bird flu in humans treated?
Studies suggest that the prescription medicines approved for human flu viruses would work in preventing bird flu infection in humans. However, flu viruses can become resistant to these drugs, so these medications may not always work.
What is the risk to humans from bird flu?
The risk from bird flu is generally low to most people because the viruses occur mainly among birds and do not usually infect humans. However, during an outbreak of bird flu among poultry (domesticated chicken, ducks, turkeys), there is a possible risk to people who have contact with infected birds or surfaces that have been contaminated with excretions from infected birds. The current outbreak of avian influenza A (H5N1) among poultry in Asia (see below) is an example of a bird flu outbreak that has caused human infections and deaths. In such situations, people should avoid contact with infected birds or contaminated surfaces, and should be careful when handling and cooking poultry. For more information about avian influenza and food safety issues, visit the World Health Organization website.
Influenza A (H5N1) virus – also called “H5N1 virus” – is an influenza A virus subtype that occurs mainly in birds. It was first isolated from birds (terns) in South Africa in 1961. Like all bird flu viruses, H5N1 virus circulates among birds worldwide, is very contagious among birds, and can be deadly.
The H5N1 virus does not usually infect humans. In 1997, however, the first case of spread from a bird to a human was seen during an outbreak of bird flu in poultry in Hong Kong. The virus caused severe respiratory illness in 18 people, 6 of whom died. Since that time, there have been other cases of H5N1 infection among humans. Most recently, human cases of H5N1 infection have occurred in Thailand, Vietnam and Cambodia during large H5N1 outbreaks in poultry. The death rate for these reported cases has been about 50 percent. Most of these cases occurred from contact with infected poultry or contaminated surfaces; however, it is thought that a few cases of human-to-human spread of H5N1 have occurred.
So far, spread of H5N1 virus from person to person has been rare and spread has not continued beyond one person. However, because all influenza viruses have the ability to change, scientists are concerned that the H5N1 virus could one day be able to infect humans and spread easily from one person to another. Because these viruses do not commonly infect humans, there is little or no immune protection against them in the human population. If the H5N1 virus were able to infect people and spread easily from person to person, an “influenza pandemic” (worldwide outbreak of disease) could begin. No one can predict when a pandemic might occur. However, experts from around the world are watching the H5N1 situation in Asia very closely and are preparing for the possibility that the virus may begin to spread more easily and widely from person to person.
The H5N1 virus currently infecting birds in Asia that has caused human illness and death is resistant to amantadine and rimantadine, two antiviral medications commonly used for influenza. Two other antiviral medications, oseltamavir and zanamavir, would probably work to treat flu caused by the H5N1 virus, though studies still need to be done to prove that they work.
There currently is no vaccine to protect humans against the H5N1 virus that is being seen in Asia. However, vaccine development efforts are under way. Research studies to test a vaccine to protect humans against H5N1 virus began in April 2005. (Researchers are also working on a vaccine against H9N2, another bird flu virus subtype.) For more information about the H5N1 vaccine development process, visit the National Institutes of Health website.
posted by baby and kids at 12:04 PM
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