Swine Flu Cases Appear To Have Peaked

The Los Angeles Times:"The current wave of pandemic H1N1 appears to have peaked, with four weeks of declines in several key indicators, the Centers for Disease Control and Prevention said Monday. Despite the decrease, the outbreak is continuing to take a heavy toll of hospitalizations and deaths, especially among children. Widespread activity of H1N1, also called swine flu, was reported in 32 states ... in the week ending Nov. 21, down from 43 states the week before and 48 a month ago. Influenza-like illnesses accounted for 4.3% of all visits to doctors' offices during the week, down from nearly double that proportion in October. That is still well above the normal level, 2.3%, for this time of year, however" (Maugh, 12/1).

The Washington Post: "While officials warned that the number of people getting infected with the H1N1 virus remains high, and cases could surge again, the extended period of falling activity suggests that the intensity of the outbreak has reached a high. ... 'We're far from being out of the woods,' [Thomas Skinner, spokesman for the Centers for Disease Control and Prevention in Atlanta] said. 'There's still a lot of flu out there. And we wouldn't be surprised to see another uptick in activity as we approach the end of December and beginning of January, when kids come back from Christmas break.' But other experts said they thought the wave had peaked" (Stein, 12/1).

USA Today reports: "The steady decline in the USA and elsewhere prompted the World Health Organization to propose Friday that swine flu may have peaked in North America, the Caribbean and parts of Europe, though the 'winter influenza season continues to be intense.' U.S. officials challenged WHO's hopeful assessment, saying it is too soon to declare that swine flu is tapering off. ... As of Monday, 66 million doses of swine flu vaccine were available for states to order, and more were on the way, the CDC's Thomas Skinner says" (Sternberg, 11/30).

Meanwhile, The San Bernardino (Calif.) Sun reports that fewer blacks are receiving the vaccine: "San Bernardino County public health officials this week plan to make a special pitch to get more blacks to roll up their sleeves for the H1N1 vaccine. ... Alonzo Louis Plough, director of emergency preparedness and response at the Los Angeles County Department of Public Health, said last week that his agency had already made attempts at special outreach and participation in the H1N1 campaign, and participation is still lagging. ... Dr. Eric Frykman, health officer for Riverside County, said that he has asked clinic managers to informally start tracking participation by ethnic group" (Steinberg, 11/29).

This information was reprinted from kaiserhealthnews.org with kind permission from the Henry J. Kaiser Family Foundation. You can view the entire Kaiser Daily Health Policy Report, search the archives and sign up for email delivery at

Swine flu deaths mount to six India

The number of people to die of swine flu in India has risen to six with the death of a number of patients over the weekend, health officials say.

Six patients are reported to be in a serious condition in the western city of Pune, which has recorded more cases than anywhere else in India.

A number of schools in the country have been shut temporarily over fears of children contracting the disease.

Officials say there are more than 800 cases of the H1N1 flu strain in India.

The virus is thought to have killed almost 800 people around the world.

A 53-year-old doctor of indigenous medicine and a four-year-old boy died in hospitals in western Pune and southern Chennai cities early on Monday, taking the number of deaths caused by swine flu to six.

Over the weekend, three people died of the flu in western India - a 43-year-old businessman who was visiting Ahmedabad city in Gujarat state; a 42-year-old teacher in Pune city; and a 53-year-old woman in Mumbai city.

Last Monday, a 14-year-old girl became the first person in the country to die of swine flu.

Rising concerns

Health officials say that the country had enough stocks of the anti-flu drug Tamiflu.

However, panic is growing among the people with swine flu deaths making it to the front pages of newspapers and main TV news.

Several schools in western Indian and the capital, Delhi, have closed temporarily as fears grow about children contracting the flu.

In Delhi, where some 228 cases have been confirmed, health officials say that the people are panicking "because the symptoms of swine flu and common influenza are similar".

As the number of flu deaths rise in the country, health officials have asked people not to panic.

Indian PM Manmohan Singh has asked the health ministry to step up preparedness against the disease and coordinate with state governments to spread the disease.

"All state governments have been asked to set up their own swine flu helplines, create more quarantine wards not only in their hospitals but also in the big private hospitals," federal Health Minister Ghulam Nabi Azad said.

The BBC's Soutik Biswas in Delhi says though the number of swine flu deaths in India was still low, there are concerns over the ability of the badly-run and under equipped government hospitals to handle the rising tide of patients.

Also, the 12 swine flu testing centres in India will not be sufficient if the number of cases rise sharply, our correspondent says.

"We need to work out a public-private partnership between the hospitals to tackle the flu. We need to take the people, doctors and media into confidence so panic does not spread," federal Junior Health Minister Dinesh Trivedi told the BBC.

Last week, the World Health Organization announced that the first swine flu vaccines are likely to be licensed for use in the general population in September.

The swine flu (H1N1) virus first emerged in Mexico in April and has since spread to 74 countries.

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Pune/Chennai, Aug 10 (PTI) A 35-year-old ayurvedic doctor and a four-year-old boy died of swine flu in Pune and Chennai today, taking the toll due to the dreaded viral infection in the country to six. The medic, Babasahib Mane, died in the Sassoon Hospital in Pune this morning, becoming the third person in the worst-hit Maharashtra city to succumb to swine flu, a senior health official said.

Mane was ailing for sometime and blood had been found in his sputum in the last couple of days, he said. In Chennai, a four-year-old boy, who was admitted to a private hospital with kidney and liver-related complications and had tested positive for swine flu, died this morning, health officials said.

The boy had also been suffering from asthma. This is the first case of flu death in the city.

"The boy was in a very critical condition. He had been suffering from asthma and he had been taken from one hospital to another for various complications.

Ultimately he landed up in this hospital for a kidney-related problem.

and they found the boy testing positive (for swine flu)," Tamil Nadu Health Secretary V K Subburaj said.

The boy, who was on a ventilator, died following "multi- organ failure," S Ilango, Director of Public Health, said. With the two deaths today, the swine flu toll in the country has climbed to six.

Important information about swine flu

Swine flu is the common name that has been given to a new strain of influenza. It is called swine flu because it is thought to have originated in pigs, but this is not known for certain.

The most common symptoms are fever, sore throat, diarrhoea, headache, feeling generally unwell and a dry cough – in other words, symptoms very similar to seasonal influenza. Most people recover within a week, even without special treatment.

Pandemic
The virus was first identified in Mexico in April and has since become a pandemic, which means it has spread around the globe. It has spread quickly because it is a new type of influenza virus that few, if any, people have full resistance to.

Flu pandemics are a natural event that occur from time to time. Last century, there were flu pandemics in 1918, 1957 and 1968, when millions of people died across the world.

So far the new virus is known to have infected 77,000 people in over 100 countries around the world. However, this figure is almost certainly a large underestimate because it reflects only those cases which have been confirmed by laboratory tests.

In the majority of cases the virus has proved relatively mild. However, more than 300 people have died globally and its 'risk profile' is still not fully understood. For this reason, and because all viruses can mutate to become more potent, scientists are advising caution.

The situation in the UK
There have been nearly 10,000 cases confirmed in the UK since the outbreak started here on 27 April. Of these, over 100 have involved hospitalisation, and 15 people have died.

The UK formally moved from a 'containment' to a 'treatment' phase for swine flu on 2 July. This meant that intensive efforts to contain swine flu, via automatic school closures, for example, ended in order to free up capacity to treat the increasing numbers of people who are contracting swine flu daily.

As in other countries, the majority of cases reported so far in the UK have been mild. Only a small number have led to serious illness, and these have frequently been where patients have had underlying health problems.

There has been an argument put forward that government should restrict antivirals to those groups who are most at risk of developing serious complications from swine flu. In other words, if people are otherwise healthy, then the NHS should let the virus run its course, treating it with paracetamol and bed rest as you would normal flu.

However, the government's Scientific Advisory Group on Emergencies (SAGE) believes that there is still some doubt about the risk profile of the virus. For instance, there are reports of some cases in Argentina where young, healthy adults have apparently become extremely ill from swine flu.

While there is still this doubt, the government has decided to continue offering the antiviral medicines Tamiflu or Relenza to everyone with swine flu at their doctor’s discretion.

High-risk groups
Some people are more at risk of serious illness if they catch swine flu, and will need to start taking antivirals as soon as they are confirmed with the illness. On occasion, doctors may advise some high-risk patients to take antivirals before they have symptoms if someone close to them has swine flu.

The risk profile of the virus is still being studied but it is already known that the following people are particularly vulnerable:

people with:
- chronic lung disease,
- chronic heart disease,
- chronic kidney disease,
- chronic liver disease,
- chronic neurological disease,
- immunosuppression (whether caused
by disease or treatment), and
- diabetes mellitus,
patients who have had drug treatment for asthma in the past three years,
pregnant women,
people aged 65 years and older, and
children under five years old.
Swine flu vaccine
A vaccine to protect against swine flu is being developed but it is not available yet.

The first batches of vaccine are expected to arrive in late August, and 30 million double doses – enough for half the population – are expected to be available by the end of the year.

The government has ordered enough vaccine for the whole population and, when it becomes available, will focus on those at the greatest risk first.

Catch it, bin it, kill it
Although the UK has moved to a treatment phase for swine flu, it is important that people continue to do everything they can to stop the virus from spreading.

The key is to practise good respiratory and hand hygiene. In other words, remember to Catch it, Bin It, Kill It. Catch your sneeze in a tissue, place it quickly in a bin and wash your hands and surfaces regularly to kill the virus.

Home Remedies to Avoid Swine Flu

Always cover your mouth and nose when coughing or sneezing; ideally use something disposable like a tissue. Avoid touching your face, nose or mouth too frequently with your hands since swine flu appears to be transmitted through respiratory droplets in the same fashion as the common cold.

Wash your hands frequently with soap and water since swine flu like other viruses can be contracted by touching objects contaminated by the virus. It's unsure how long the swine flu virus can survive on surrounding surfaces.

Though alcohol based hand sanitizers don't routinely kill viruses they probably do offer some limited protection in preventing swine flu infections.

If swine flu infections have been medically confirmed in your area consider avoiding large public gatherings. Individuals can be contagious with the swine flu virus for several day before demonstrating any signs or symptoms of infection. Be particularly careful about indoor gatherings where air circulates poorly.

If you're really paranoid and don't mind looking odd then consider wearing a respiratory mask.. This barrier method does offer some basic protection against infection though not all masks are created equally. Higher quality masks capable of filtering out some respiratory infections are more expensive.

If you start feeling ill with cold or flu-like symptoms do not go to work. Stay home and begin the usual home remedies for colds and flu. Contact your health care provider, local health department or hospital emergency room if your symptoms worsen or fail to improve for information about where to go to be screened for possible swine flu infection.



What is Swine Flu? its signs and symptoms
In this video, Dr. Joe Bresee with the CDC Influenza Division describes swine flu - its signs and symptoms, how it's transmitted, medicines to treat it, steps people can take to protect themselves from it, and what people should do if they become ill.

What is H1N1 (swine flu)?
H1N1 (referred to as “swine flu” early on) is a new influenza virus causing illness in people. This new virus was first detected in people in the United States in April 2009. Other countries, including Mexico and Canada, have reported people sick with this new virus. This virus is spreading from person-to-person, probably in much the same way that regular seasonal influenza viruses spread.

To be more specific, Swine flu is a respiratory disease, caused by influenza type A which infects pigs. There are of many types, and the infection are constantly changing. Until now it had not normally infected humans, but the latest form clearly does, and is spread from person to person - probably through coughing and sneezing.

The World Health Organization has confirmed that at least some of the human cases are a never-before- seen version of the H1N1 strain of influenza type A. H1N1 is the same strain which causes seasonal outbreaks of flu in humans on a regular basis. But this latest version of H1N1 is different: it contains genetic material that is typically found in strains of the virus that affect humans, birds and swine.

Flu viruses have the ability to swap genetic components with each other, and it seems likely that the new version of H1N1 resulted from a mixing of different versions of the virus, which may usually affect different species, in the same animal host.

Pigs provide an excellent 'melting pot' for these viruses to mix and match with each other.

Symptoms of swine flu in humans appear to be similar to those produced by standard, seasonal flu. These include fever, cough, sore throat, body aches, chills and fatigue. Most cases so far reported around the world appear to be mild, but in Mexico lives have been lost.

Why is this new H1N1 virus sometimes called “swine flu”?
This virus was originally referred to as “swine flu” because laboratory testing showed that many of the genes in this new virus were very similar to influenza viruses that normally occur in pigs in North America. But further study has shown that this new virus is very different from what normally circulates in North American pigs. It has two genes from flu viruses that normally circulate in pigs in Europe and Asia and avian genes and human genes. Scientists call this a “quadruple reassortant” virus.

Novel H1N1 Flu in Humans

Are there human infections with this H1N1 virus in the U.S.?
Yes. Cases of human infection with this H1N1 influenza virus were first confirmed in the U.S. in Southern California and near Guadalupe County, Texas. The outbreak intensified rapidly from that time and more and more states have been reporting cases of illness from this virus.

Is this new H1N1 virus contagious?
CDC has determined that this new H1N1 virus is contagious and is spreading from human to human. However, at this time, it is not known how easily the virus spreads between people.

What are the signs and symptoms of this virus in people?
The symptoms of this new H1N1 flu virus in people are similar to the symptoms of seasonal flu and include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills and fatigue. A significant number of people who have been infected with this virus also have reported diarrhea and vomiting. Also, like seasonal flu, severe illnesses and death has occurred as a result of illness associated with this virus.

How severe is illness associated with this new H1N1 virus?
It’s not known at this time how severe this virus will be in the general population. CDC is studying the medical histories of people who have been infected with this virus to determine whether some people may be at greater risk from infection, serious illness or hospitalization from the virus. In seasonal flu, there are certain people that are at higher risk of serious flu-related complications. This includes people 65 years and older, children younger than five years old, pregnant women, and people of any age with chronic medical conditions. It’s unknown at this time whether certain groups of people are at greater risk of serious flu-related complications from infection with this new virus. CDC also is conducting laboratory studies to see if certain people might have natural immunity to this virus, depending on their age.

How does this new H1N1 virus spread?
Spread of this H1N1 virus is thought to be happening in the same way that seasonal flu spreads. Flu viruses are spread mainly from person to person through coughing or sneezing by people with influenza. Sometimes people may become infected by touching something with flu viruses on it and then touching their mouth or nose.

How long can an infected person spread this virus to others?
At the current time, CDC believes that this virus has the same properties in terms of spread as seasonal flu viruses. With seasonal flu, studies have shown that people may be contagious from one day before they develop symptoms to up to 7 days after they get sick. Children, especially younger children, might potentially be contagious for longer periods. CDC is studying the virus and its capabilities to try to learn more and will provide more information as it becomes available.
Exposures Not Thought to Spread New H1N1 Flu

Can I get infected with this new H1N1 virus from eating or preparing pork?
No. H1N1 viruses are not spread by food. You cannot get this new HIN1 virus from eating pork or pork products. Eating properly handled and cooked pork products is safe.

Is there a risk from drinking water?
Tap water that has been treated by conventional disinfection processes does not likely pose a risk for transmission of influenza viruses. Current drinking water treatment regulations provide a high degree of protection from viruses. No research has been completed on the susceptibility of the novel H1N1 flu virus to conventional drinking water treatment processes. However, recent studies have demonstrated that free chlorine levels typically used in drinking water treatment are adequate to inactivate highly pathogenic H5N1 avian influenza. It is likely that other influenza viruses such as novel H1N1 would also be similarly inactivated by chlorination. To date, there have been no documented human cases of influenza caused by exposure to influenza-contaminated drinking water.

Can the new H1N1 flu virus be spread through water in swimming pools, spas, water parks, interactive fountains, and other treated recreational water venues?
Influenza viruses infect the human upper respiratory tract. There has never been a documented case of influenza virus infection associated with water exposure. Recreational water that has been treated at CDC recommended disinfectant levels does not likely pose a risk for transmission of influenza viruses. No research has been completed on the susceptibility of the H1N1 influenza virus to chlorine and other disinfectants used in swimming pools, spas, water parks, interactive fountains, and other treated recreational venues. However, recent studies have demonstrated that free chlorine levels recommended by CDC (1–3 parts per million [ppm or mg/L] for pools and 2–5 ppm for spas) are adequate to disinfect avian influenza A (H5N1) virus. It is likely that other influenza viruses such as novel H1N1 virus would also be similarly disinfected by chlorine.

Can H1N1 influenza virus be spread at recreational water venues outside of the water?
Yes, recreational water venues are no different than any other group setting. The spread of this novel H1N1 flu is thought to be happening in the same way that seasonal flu spreads. Flu viruses are spread mainly from person to person through coughing or sneezing of people with influenza. Sometimes people may become infected by touching something with flu viruses on it and then touching their mouth or nose.

Prevention & Treatment

What can I do to protect myself from getting sick?
There is no vaccine available right now to protect against this new H1N1 virus. There are everyday actions that can help prevent the spread of germs that cause respiratory illnesses like influenza.

Take these everyday steps to protect your health:

* Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
* Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hand cleaners are also effective.

* Avoid touching your eyes, nose or mouth. Germs spread this way.
* Try to avoid close contact with sick people.
* Stay home if you are sick for 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer. This is to keep from infecting others and spreading the virus further.

Other important actions that you can take are:

* Follow public health advice regarding school closures, avoiding crowds and other social distancing measures.
* Be prepared in case you get sick and need to stay home for a week or so; a supply of over-the-counter medicines, alcohol-based hand rubs, tissues and other related items might could be useful and help avoid the need to make trips out in public while you are sick and contagious.

What is the best way to keep from spreading the virus through coughing or sneezing?
If you are sick, limit your contact with other people as much as possible. If you are sick, stay home for 7 days after your symptoms begin or until you have been symptom-free for 24 hours, whichever is longer. Cover your mouth and nose with a tissue when coughing or sneezing. Put your used tissue in the waste basket. Then, clean your hands, and do so every time you cough or sneeze.

What is the best technique for washing my hands to avoid getting the flu?
Washing your hands often will help protect you from germs. Wash with soap and water or clean with alcohol-based hand cleaner. CDC recommends that when you wash your hands -- with soap and warm water -- that you wash for 15 to 20 seconds. When soap and water are not available, alcohol-based disposable hand wipes or gel sanitizers may be used. You can find them in most supermarkets and drugstores. If using gel, rub your hands until the gel is dry. The gel doesn't need water to work; the alcohol in it kills the germs on your hands.

What should I do if I get sick?
If you live in areas where people have been identified with new H1N1 flu and become ill with influenza-like symptoms, including fever, body aches, runny or stuffy nose, sore throat, nausea, or vomiting or diarrhea, you should stay home and avoid contact with other people, except to seek medical care.

If you have severe illness or you are at high risk for flu complications, contact your health care provider or seek medical care. Your health care provider will determine whether flu testing or treatment is needed

If you become ill and experience any of the following warning signs, seek emergency medical care.

In children, emergency warning signs that need urgent medical attention include:

* Fast breathing or trouble breathing
* Bluish or gray skin color
* Not drinking enough fluids
* Severe or persistent vomiting
* Not waking up or not interacting
* Being so irritable that the child does not want to be held
* Flu-like symptoms improve but then return with fever and worse cough

In adults, 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
* Confusion
* Severe or persistent vomiting
* Flu-like symptoms improve but then return with fever and worse cough

Are there medicines to treat infection with this new virus?
Yes. CDC recommends the use of oseltamivir or zanamivir for the treatment and/or prevention of infection with the new H1N1 flu virus. Antiviral drugs are prescription medicines (pills, liquid or an inhaler) that fight against the flu by keeping flu viruses from reproducing in your body. If you get sick, antiviral drugs can make your illness milder and make you feel better faster. They may also prevent serious flu complications. During the current outbreak, the priority use for influenza antiviral drugs during is to treat severe influenza illness.

The US authorities say that two drugs commonly used to treat flu, Tamiflu and Relenza, seem to be effective at treating cases that have occurred there so far. However, the drugs must be administered at an early stage to be effective. Use of these drugs may also make it less likely that infected people will pass the virus on to others


What is CDC’s recommendation regarding "swine flu parties"?
"Swine flu parties" are gatherings during which people have close contact with a person who has novel H1N1 flu in order to become infected with the virus. The intent of these parties is to become infected with what for many people has been a mild disease, in the hope of having natural immunity to the novel H1N1 flu virus that might circulate later and cause more severe disease.

CDC does not recommend "swine flu parties" as a way to protect against novel H1N1 flu in the future. While the disease seen in the current novel H1N1 flu outbreak has been mild for many people, it has been severe and even fatal for others. There is no way to predict with certainty what the outcome will be for an individual or, equally important, for others to whom the intentionally infected person may spread the virus.

CDC recommends that people with novel H1N1 flu avoid contact with others as much as possible. They should stay home from work or school for 7 days after the onset of illness or until at least 24 hours after symptoms have resolved, whichever is longer.

Contamination & Cleaning

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.

What kills influenza virus?
Influenza virus is destroyed by heat (167-212°F [75-100°C]). In addition, several chemical germicides, including chlorine, hydrogen peroxide, detergents (soap), iodophors (iodine-based antiseptics), and alcohols are effective against human influenza viruses if used in proper concentration for a sufficient length of time. For example, wipes or gels with alcohol in them can be used to clean hands. The gels should be rubbed into hands until they are dry.

What surfaces are most likely to be sources of contamination?
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 their own eyes, mouth or nose before washing their hands.

How should waste disposal be handled to prevent the spread of influenza virus?
To prevent the spread of influenza virus, it is recommended that tissues and other disposable items used by an infected person be thrown in the trash. Additionally, persons should wash their hands with soap and water after touching used tissues and similar waste.

What household cleaning should be done to prevent the spread of influenza virus?
To prevent the spread of influenza virus it is important to keep surfaces (especially bedside tables, surfaces in the bathroom, kitchen counters and toys for children) clean by wiping them down with a household disinfectant according to directions on the product label.

How should linens, eating utensils and dishes of persons infected with influenza virus be handled?
Linens, eating utensils, and dishes belonging to those who are sick do not need to be cleaned separately, but importantly these items should not be shared without washing thoroughly first.
Linens (such as bed sheets and towels) should be washed by using household laundry soap and tumbled dry on a hot setting. Individuals should avoid “hugging” laundry prior to washing it to prevent contaminating themselves. Individuals should wash their hands with soap and water or alcohol-based hand rub immediately after handling dirty laundry.

Eating utensils should be washed either in a dishwasher or by hand with water and soap.

The first case has already been reported from India from neighboring state of Andhra Pradesh.

What about bird flu?
The strain of bird flu which has caused scores of human deaths in South East Asia in recent years is a different strain to that responsible for the current outbreak of swine flu.

The latest form of swine flu is a new type of the H1N1 strain, while bird, or avian flu, is H5N1.

Experts fear H5N1 hold the potential to trigger a pandemic because of its ability to mutate rapidly.

However, up until now it has remained very much a disease of birds.

Those humans who have been infected have, without exception, worked closely with birds, and cases of human-to-human transmission are extremely rare - there is no suggestion that H5N1 has gained the ability to pass easily from person to person.

Signs and symptoms

According to the Centers for Disease Control and Prevention (CDC), in humans the symptoms of swine flu are similar to those of influenza and of influenza-like illness in general. Symptoms include fever, cough, sore throat, body aches, headache, chills and fatigue. The 2009 outbreak has shown an increased percentage of patients reporting diarrhea and vomiting.
Because these symptoms are not specific to swine flu, a differential diagnosis of probable swine flu requires not only symptoms but also a high likelihood of swine flu due to the person's recent history. For example, during the 2009 swine flu outbreak in the United States, CDC advised physicians to "consider swine influenza infection in the differential diagnosis of patients with acute febrile respiratory illness who have either been in contact with persons with confirmed swine flu, or who were in one of the five U.S. states that have reported swine flu cases or in Mexico during the 7 days preceding their illness onset." A diagnosis of confirmed swine flu requires laboratory testing of a respiratory sample (a simple nose and throat swab).

Classification

SIV strains isolated to date have been classified either as Influenzavirus C or one of the various subtypes of the genus Influenzavirus A.
Influenza A
Swine influenza is known to be caused by influenza A subtypes H1N1, H1N2, H3N1,H3N2,and H2N3.
In swine, three influenza A virus subtypes (H1N1, H3N2, and H1N2) are circulating throughout the world. In the United States, the H1N1 subtype was exclusively prevalent among swine populations before 1998; however, since late August 1998, H3N2 subtypes have been isolated from pigs. As of 2004, H3N2 virus isolates in US swine and turkey stocks were triple reassortants, containing genes from human (HA, NA, and PB1), swine (NS, NP, and M), and avian (PB2 and PA) lineages.

Interaction with H5N1

Avian influenza virus H3N2 is endemic in pigs in China and has been detected in pigs in Vietnam, increasing fears of the emergence of new variant strains. Health experts[who?] say pigs can carry human influenza viruses, which can combine (i.e. exchange homologous genome sub-units by genetic reassortment) with H5N1, passing genes and mutating into a form which can pass easily among humans. H3N2 evolved from H2N2 by antigenic shift. In August 2004, researchers in China found H5N1 in pigs.
Nature magazine reported that Chairul Nidom, a virologist at Airlangga University's tropical disease center in Surabaya, East Java, conducted a survey of swine infections with H5N1 in 2005. He tested the blood of 10 apparently healthy pigs housed near poultry farms in West Java where avian flu had broken out. Five of the pig samples contained the H5N1 virus. The Indonesian government has since found similar results in the same region. Additional tests of 150 pigs outside the area were negative.

Classification

SIV strains isolated to date have been classified either as Influenzavirus C or one of the various subtypes of the genus Influenzavirus A.
Influenza A
Swine influenza is known to be caused by influenza A subtypes H1N1,[10] H1N2,[10] H3N1,[11] H3N2,[10] and H2N3.[12]
In swine, three influenza A virus subtypes (H1N1, H3N2, and H1N2) are circulating throughout the world. In the United States, the H1N1 subtype was exclusively prevalent among swine populations before 1998; however, since late August 1998, H3N2 subtypes have been isolated from pigs. As of 2004, H3N2 virus isolates in US swine and turkey stocks were triple reassortants, containing genes from human (HA, NA, and PB1), swine (NS, NP, and M), and avian (PB2 and PA) lineages.

Interaction with H5N1

Avian influenza virus H3N2 is endemic in pigs in China and has been detected in pigs in Vietnam, increasing fears of the emergence of new variant strains. Health experts[who?] say pigs can carry human influenza viruses, which can combine (i.e. exchange homologous genome sub-units by genetic reassortment) with H5N1, passing genes and mutating into a form which can pass easily among humans. H3N2 evolved from H2N2 by antigenic shift. In August 2004, researchers in China found H5N1 in pigs.
Nature magazine reported that Chairul Nidom, a virologist at Airlangga University's tropical disease center in Surabaya, East Java, conducted a survey of swine infections with H5N1 in 2005. He tested the blood of 10 apparently healthy pigs housed near poultry farms in West Java where avian flu had broken out. Five of the pig samples contained the H5N1 virus. The Indonesian government has since found similar results in the same region. Additional tests of 150 pigs outside the area were negative.