Re Serch swin flu

موضوع: Re Serch swin flu الأربعاء 10 مارس 2010, 6:17 pm

Re Serch swin flu

The 2009 flu pandemic is a global outbreak of a new strain of influenza A virus subtype H1N1, termed Pandemic H1N1/09 virus by the World Health Organization (WHO), that was first identified in April 2009. The disease has also been termed novel influenza A (H1N1) and 2009 H1N1 flu by the U.S. Centers for Disease Control and Prevention (CDC), and colloquially called swine flu.

The outbreak was first observed in Mexico, with evidence that there had been an ongoing epidemic for months before it was officially recognized as such. The Mexican government soon closed most of Mexico City's public and private offices and facilities to contain the spread of the virus. As the virus quickly spread globally, clinics were overwhelmed by testing and treating patients, and the WHO and the CDC eventually stopped counting all cases and focused instead on tracking major outbreaks. On June 11, 2009, the WHO declared the outbreak to be a pandemic.

Only mild symptoms are experienced by the overwhelming majority of victims, but there are exceptions. Some persons are in higher risk groups, such as those with asthma, diabetes, obesity, heart disease, children with neurodevelopmental conditions, or persons who are pregnant or have a weakened immune system. There are small subsets of patients, even among young persons previously healthy, who rapidly develop severe pneumonia, typically 3 to 5 days after initial onset of symptoms. Deterioration can be very rapid, with many patients progressing to respiratory failure within 24 hours, requiring intensive care and ventilation support.

Like other influenza viruses, swine flu is typically contracted by inhaling air that has been contaminated by an infected person coughing or sneezing, or by touching one's nose or mouth with hands that have previously touched contaminated surfaces and have not been disinfected. Symptoms, which last up to a week, are similar to those of seasonal flu, and can include fever, sneezing, sore throat, cough, headache, and muscle or joint pains. To avoid spreading the infection, the CDC recommended that those with symptoms stay home from school, work, and crowded settings; wearing facial masks was not recommended except in health care settings.

# Initial outbreaks :

While it is not known precisely where or when the virus originated, analyses in scientific journals have suggested that the H1N1 strain responsible for the current outbreak first evolved in September 2008 and circulated amongst humans for several months before being formally recognized and identified as a novel strain of influenza.

Mexico :

The virus was first reported in two US children in March 2009, but health officials have reported that it apparently infected people as early as January 2009 in Mexico. The outbreak was first detected in Mexico City on March 18, 2009; immediately after the outbreak was officially announced, Mexico requested material support from the US, and within days of the outbreak Mexico City was "effectively shut down". Some countries canceled flights to Mexico while others halted trade. Calls to close the border to contain the spread were rejected. Mexico already had hundreds of cases before the outbreak was officially recognized, and was therefore in the midst of a "silent epidemic". As a result, Mexico was reporting only the most serious cases, possibly leading to a skewed initial estimate of the case fatality rate."

United States :

The new strain was first identified by the CDC in two children, neither of whom had been in contact with pigs. The first case, from San Diego County, California, was confirmed from clinical specimens (nasopharyngeal swab) examined by the CDC on April 14, 2009. A second case, from nearby Imperial County, California, was confirmed on April 17. The patient in the first confirmed case had flu symptoms including fever and cough on clinical exam on March 30, and the second on March 28.

The first confirmed swine flu death occurred at Texas Children's Hospital in Houston, Texas.

# Nomenclature :

The initial outbreak was called the "H1N1 influenza". The CDC began also referring to it as "Novel Influenza A (H1N1)". In the Netherlands, it was originally called "Pig Flu", but is now called "New Influenza A (H1N1)" by the national health institute, although the media and general population use the name "Mexican Flu". South Korea and Israel briefly considered calling it the "Mexican virus". Later, the South Korean press used "SI", short for "swine influenza". Taiwan suggested the names "H1N1 flu" or "new flu", which most local media adopted. The World Organization for Animal Health proposed the name "North American influenza". The European Commission adopted the term "novel flu virus".

# Symptoms :

The symptoms of swine flu are similar to other influenzas, and may include a fever, coughing (typically a "dry cough"), headaches, muscle or joint pain, sore throat, chills, fatigue, and runny nose. Diarrhea, vomiting, and neurological problems were also reported in some cases. People at higher risk of serious complications include people age 65 and older, children younger than 5 years old, children with neurodevelopmental conditions, pregnant women (especially during the third trimester), and people of any age with underlying medical conditions, such as asthma, diabetes, obesity, heart disease, or a weakened immune system (e.g., taking immunosuppressive medications or infected with HIV). Most hospitalizations in the US were people with such underlying conditions, according to the CDC.

In adults :

In adults, shortness of breath, pain in the chest or abdomen, sudden dizziness, or confusion may require emergency care. In both children and adults, persistent vomiting or the return of flu-like symptoms that include a fever and cough may require medical attention. And if it follows the same pattern as in children, a relapse with high fever may in fact be pneumonia.

In children :

As with the seasonal flu, certain symptoms may require emergency medical attention. In children, signs of respiratory distress include blue lips and skin, dehydration, rapid breathing, excessive sleeping, seizures, and significant irritability including a lack of desire to be held. Although "too early" to tell for certain, Dr. Frieden has noted that so far the swine flu "seems to be taking a heavier toll among chronically ill children than the seasonal flu usually does." Of the children who have died so far, nearly two-thirds had pre-existing nervous system disorders, such as cerebral palsy, muscular dystrophy, or developmental delays. "Children with nerve and muscle problems may be at especially high risk for complications," the CDC report stated. In children without chronic health problems, it is a warning sign if they seem to recover from the flu but then relapse with a high fever.

Researchers in Australia and New Zealand have reaffirmed that infants under the age of 1 year have the highest risk of developing severe illness from swine flu.

# Vaccination and prevention :

The pandemic is expected to peak by mid-winter in the Northern hemisphere. The CDC recommended that initial vaccine doses should go to priority groups such as pregnant women, people who live with or care for babies under six months old, children six months to four years old and health-care workers.

Health officials worldwide were also concerned because the virus was new and could easily mutate and become more virulent, even though most flu symptoms were mild and lasted only a few days without treatment. Officials also urged communities, businesses and individuals to make contingency plans for possible school closures, multiple employee absences for illness, surges of patients in hospitals and other effects of potentially widespread outbreaks.

Travel precautions :

The WHO stated that containment was not a feasible option and that countries should focus on mitigating the effect of the virus. It did not recommend closing borders or restricting travel. On April 26, 2009, the Chinese government announced that visitors returning from flu-affected areas who experienced flu-like symptoms within two weeks would be quarantined. On May 2, 2009, China suspended flights from Tijuana to Shanghai.

US airlines had made no major changes as of the beginning of June 2009, but continued standing practices that included looking for passengers with symptoms of flu, measles, or other infections, and relying on in-flight air filters to ensure that aircraft were sanitized. Masks were not generally provided by airlines and the CDC did not recommend that airline crews wear them. Some non-US airlines, mostly Asian ones, including Singapore Airlines, China Eastern Airlines, China Southern Airlines, Cathay Pacific, and Mexicana Airlines, took measures such as stepping up cabin cleaning, installing state-of-the-art air filters, and allowing in-flight staff to wear face masks.

Schools :

The swine flu outbreak has led to numerous precautionary school closures in several countries. Rather than closing schools, the CDC recommended in August that students and school workers with flu symptoms should stay home for either seven days total, or until 24 hours after symptoms subside—whichever is longer. The CDC also recommended that colleges should consider suspending fall 2009 classes if the virus begins to cause severe illness in a significantly larger share of students than last spring. They have additionally urged schools to suspend any rules, including penalizing late papers or missed classes, or requiring a doctor's note, to enforce "self-isolation" and prevent students from venturing out while ill; schools were advised to set aside a room for people developing flu-like symptoms while they wait to go home and that surgical masks be used for ill students or staff and those caring for them.

US government officials are especially concerned about schools because the swine flu virus appears to disproportionately affect young and school-age people, between ages 6 months to 24 years of age, making them one of the top priority groups when it comes to the new vaccine. They state that the most important actions are to encourage and facilitate good hand washing and covering coughs and sneezes, flu vaccinations for people at risk; and to separate sick people from healthy people as soon as possible.

Workplace :

The CDC estimates that as much as 40% of the workforce, in a worst-case scenario, might be unable to work at the peak of the pandemic due to the need for many healthy adults to stay home and care for an ill family member, and advising that individuals should have steps in place should a workplace close down or a situation arise that requires working from home. The CDC further advises that persons in the workplace should stay home sick for seven days after getting the flu, or 24 hours after symptoms end, whichever is longer.

Facial masks :

The CDC does not recommend use of face masks or respirators in non-health care settings, such as schools, workplaces, or public places, with a few exceptions: people who are ill with the virus should consider wearing one when around other people, and people who are at risk for severe illness while caring for someone with the flu. There is general uncertainty among health professionals about the value of wearing either facial masks or more expensive respirators to prevent infection.

Despite the lack of evidence of effectiveness, the use of such masks is common in Asia.

Quarantines :

Countries have begun quarantining or have threatened to quarantine foreign visitors suspected of having or being in contact with others who may have been infected. In May, the Chinese government confined 21 US students and three teachers to their hotel rooms. As a result, the US State Department issued a travel alert about China's anti-flu measures and was warning travelers about traveling to China if ill. In Hong Kong, an entire hotel was quarantined with 240 guests; Australia ordered a cruise ship with 2,000 passengers to stay at sea because of a swine flu threat. Egyptian Muslims who went on the annual pilgrimage to Mecca risked being quarantined upon their return. Russia and Taiwan said they would quarantine visitors with fevers who come from areas where the flu is present. Japan quarantined 47 airline passengers in a hotel for a week in mid-May, then in mid-June India suggested pre-screening "outbound" passengers from countries thought to have a high rate of infection.