“H1N1 appears to be more contagious than seasonal influenza. The secondary attack rate of seasonal influenza ranges from 5% to 15%. Current estimates of the secondary attack rate of H1N1 range from 22% to 33%. With the exception of the outbreak in Mexico, which is still not fully understood, the H1N1 virus tends to cause very mild illness in otherwise healthy people. Outside Mexico, nearly all cases of illness, and all deaths, have been detected in people with underlying chronic conditions.”
“In the two largest and best documented outbreaks to date, in Mexico and the United States, a younger age group has been affected than seen during seasonal epidemics of influenza. Though cases have been confirmed in all age groups, from infants to the elderly, the youth of patients with severe or lethal infections is a striking feature of these early outbreaks. In terms of population vulnerability, the tendency of the H1N1 virus to cause more severe and lethal infections in people with underlying conditions is of particular concern.”
Influenza, also known as the flu, is a respiratory infection that is caused by the influenza virus and infects the nose, throat, and lungs. Influenza is contagious and is more common during winter. Young children, the elderly, and people with chronic diseases are more likely to have severe complications from getting the flu. Influenza can cause hospitalization or death in serious cases.
Since the common influenza viruses change every season, so do the vaccines. Each flu season is different depending on what viruses are spreading quickly, how many people get the vaccine, and if the vaccine is correctly matched to the influenza virus that are causing the most illness. Getting a flu vaccine is a way to protect against getting infected with influenza.
The three types of influenza are types A, B, and C. Types A and B are the viruses that are typically responsible for seasonal influenza epidemics. Type C influenza viruses can cause a mild respiratory infection, but this virus generally does not cause flu epidemics. There are also subtypes of type A influenza viruses, which are based on 2 proteins found on the virus (abbreviated H and N). A common example is H1N1. The most common influenza virus in the 2012-2013 flu season was H3N2.
WHAT ARE THE SYMPTOMS OF INFLUENZA
Someone who is infected with the influenza virus may experience some or all of these symptoms:
Fever or chills
Cough
Sore throat
Muscle, body, and head aches
Fatigue
Vomiting and diarrhea, which is more common in children with influenza.
Most of the time, a healthy person will recover from influenza in a few days or up to 2 weeks. Sometimes, people can develop serious complications from influenza, like pneumonia, bronchitis, or sinus and ear infections. Influenza can also make a chronic condition worse, like asthma. When influenza is fatal, oftentimes it is due to a bacterial infection, like pneumonia, that is secondary to the influenza.
WHAT ARE THE RISK FACTORS FOR INFLUENZA
For the 2012-2013 flu season, more than half of hospitalizations related to influenza were in adults over age 65.
People who are at higher risk for developing influenza include:
People over age 65
Children, especially those under age 2
People with chronic disease, like asthma, diabetes, lung or heart disease
People with weakened immune systems, like from cancer or HIV/AIDS
People who are morbidly obese
Pregnant women
HOW DOES INFLUENZA SPREAD ?
Influenza is contagious. Someone who is infected with the virus can be contagious 1 day before influenza symptoms develop, and up to 7 days after they are sick. Young children or people with weak immune systems are able to infect others for a longer period of time.
The influenza virus can spread when someone who is infected coughs, sneezes, or even talks. Droplets containing the influenza virus travel through the air and can be directly inhaled by another person through the mouth or nose. The droplets may also land on a surface and you could pick them up and then become infected after touching your eyes, nose, or mouth.
If you have had influenza before, your body has made antibodies to help protect you against that specific virus in the future. However, because the influenza viruses are changing every year, you won’t have antibodies against the newer virus. Vaccines attempt to have your body make antibodies against the most current influenza virus.
HOW IS FLU DIAGNOSED?
Swine flu is presumptively diagnosed clinically by the patient's history of association with people known to have the disease and their symptoms listed above. Usually, a quick test (for example, nasopharyngeal swab sample) is done to see if the patient is infected with influenza A or B virus. Most of the tests can distinguish between A and B types. The test can be negative (no flu infection) or positive for type A and B. If the test is positive for type B, the flu is not likely to be swine flu. If it is positive for type A, the person could have a conventional flu strain or swine flu. However, the accuracy of these tests has been challenged, and the U.S. Centers for Disease Control and Prevention (CDC) has not completed their comparative studies of these tests. However, a new test developed by the CDC and a commercial company reportedly can detect H1N1 reliably in about one hour; the test was formerly only available to the military. In 2010, the FDA approved a commercially available test that could detect H1N1 within four hours. Most of these rapid tests are based on PCRtechnology.
Swine flu is definitively diagnosed by identifying the particular antigens (surface proteins) associated with the virus type. In general, this test is done in a specialized laboratory and is not done by many doctors' offices or hospital laboratories. However, doctors' offices are able to send specimens to specialized laboratories if necessary. Because of the large number of novel H1N1 swine flu cases that occurred in the 2009-2010 flu season (the vast majority of flu cases [about 95%-99%] were due to novel H1N1 flu viruses), the CDC recommended only hospitalized patients' virus strains be sent to reference labs to be identified. H3N2v flu strains and other flu virus strains are diagnosed by similar methods.
HOW TO PREVENT FLU AND SWINE FLU?
1. Avoid crowded places- virus spreads through cough, sneeze.
2. Wash hands more frequently- to wash away virus if it comes in contact with hand.
3. Hands off the face technique-virus enters the body through nose, mouth and eyes, avoid unnecessarily touching the face.
4. Gargle with warm saline(salt) water twice daily- once the virus enters the body it takes 2-3 days to cause the disease, during which it multiplies in the airway cells, infecting one cell after another, by gargling we are flushing out the viruses which are released in the airways, thereby preventing them infecting other cells
5. Consume more hot beverages. It flushes the virus into the stomach where it will be killed by the acid.
6. Take more of citrus fruits, rich in vitamin C like oranges, amla, lemon
7. Consume more fluids.
8. If you have high fever for more than 2 days, visit your doctor for evaluation, it could be swine flu.
8. Use a hand kerchief while coughing and sneezing...
WHAT IS THE TREATMENT FOR SWINE FLU?
The best treatment for influenza infections in humans is prevention by vaccination. Work by several laboratories has produced vaccines. The first H1N1 vaccine released in early October 2009 was a nasal spray vaccine that was approved for use in healthy individuals ages 2-49. The injectable vaccine, made from killed H1N1, became available in the second week of Oct. 2009. This vaccine was approved for use in ages 6 months to the elderly, including pregnant females. Both of these vaccines were approved by the CDC only after they had conducted clinical trials to prove that the vaccines were safe and effective. A new influenza vaccine preparation is the intradermal (trivalent) vaccine is available; it works like the shot except the administration is less painful. It is approved for ages 18-64 years.
Almost all vaccines have some side effects. Common side effects of H1N1 vaccines (alone or in combination with other flu viral strains) are typical of flu vaccines used over many years and are as follows:
· Flu shot: Soreness, redness, minor swelling at the shot site, muscle aches, low-grade fever, and nausea do not usually last more than about 24 hours.
· Nasal spray: runny nose, low-grade fever, vomiting, headache, wheezing, cough, and sore throat
· Intradermal shot: redness, swelling, pain, headache, muscle aches, fatigue
The flu shot (vaccine) is made from killed virus particles so a person cannot get the flu from a flu shot. However, the nasal spray vaccine contains live virus that have been altered to hinder its ability to replicate in human tissue. People with a suppressed immune system should not get vaccinated with the nasal spray. Also, most vaccines that contain flu viral particles are cultivated in eggs, so individuals with an allergy to eggs should not get the vaccine unless tested and advised by their doctor that they are cleared to obtain it. Like all vaccines, rare events may occur in some rare cases (for example, swelling, weakness, or shortness of breath). If any symptoms like these develop, the person should see a physician immediately.
Two antiviral agents have been reported to help prevent or reduce the effects of swine flu. They are zanamivir (Relenza) and oseltamivir (Tamiflu), both of which are also used to prevent or reduce influenza A and B symptoms. These drugs should not be used indiscriminately, because viral resistance to them can and has occurred. Also, they are not recommended if the flu symptoms already have been present for 48 hours or more, although hospitalized patients may still be treated past the 48-hour guideline. Severe infections in some patients may require additional supportive measures such as ventilation support and treatment of other infections like pneumonia that can occur in patients with a severe flu infection. The CDC has suggested in their guidelines that pregnant females can be treated with the two antiviral agents.
Diarrhea, skin infections, hallucinations, and/or altered behavior may occur as side effects of this drug.
On Dec. 22, 2014, the FDA approved the first new anti-influenza drug (for H1N1 and other influenza virus types) in 15 years, peramivir injection (Rapivab). It is approved for use in the following settings:
· Adult patients for whom therapy with an intravenous (IV) medication is clinically appropriate, based upon one or more of the following reasons:
1.The patient is not responding to either oral or inhaled antiviral therapy, or
2.drug delivery by a route other than IV is not expected to be dependable or is not feasible, or
3. the physician decides that IV therapy is appropriate due to other circumstances.
· Pediatric patients for whom an intravenous medication clinically appropriate because:
4.The patient is not responding to either oral or inhaled antiviral therapy, or
5.drug delivery by a route other than IV is not expected to be dependable or is not feasible.
also read my blog on precautions against H1N1...my next blog is on vitamin D to prevent H1N1.. it is an interesting scientific article. please subscribe for updates.
References .
1. Centers for Disease Control and Prevention. Seasonal Influenza: Flu Basics. 2013. Web. <http://www.cdc.gov/flu/about/disease/index.htm>
2. Grant WB & Giovannucci E. The possible roles of solar ultraviolet-B radiation and vitamin D in reducing case-fatality rates from the 1918 – 1919 influenza pandemic in the United States. Dermato-Endocrinology 2009;1:215-219.
3. Rees, J. Vitamin D3 supplementation and respiratory tract infections in a randomized controlled trial. Clinical Infectious Diseases 2013;57(10):1384-1392.
4. Mayo Clinic. Influenza (Flu). 2014. Web. < http://www.mayoclinic.org/diseases-conditions/flu/basics/causes/con-20035101>
High grade fever > 38*c
