Swine flu facts: the virus, symptoms and treatment – 2009 outbreak in humans
What is swine influenza (swine flu)?
Swine influenza (swine flu) is a respiratory disease of pigs caused by type A influenza. Swine flu viruses do not normally infect humans, however, human infections with swine flu do occur, and cases of human-to-human spread of a swine flu virus have been recently confirmed.
· What is the current situation?
Human cases of a new form of influenza virus were identified in the United States, Mexico and Canada in April 2009. The influenza is a swine influenza A virus. The World Health Organization has declared the swine influenza situation to be a public health emergency of international concern.
No cases of swine influenza have been confirmed in Pakistan / India as of 28 April 2009.
The pandemic alert level has been raised by the World Health Organization.
This event is of concern because:
Swine influenza is derived from an animal influenza virus, which means that humans will likely have little or no immunity
There has been rapid spread to multiple communities overseas
Swine influenza is affecting unusual age groups (healthy, young adults)
The Swine Influenza A virus is thought to be sensitive to the new antiviral drugs oseltamivir (Tamiflu) and zanamivir (Relenza), but resistant to both amantadine and rimantadine.
· What are the symptoms?
The symptoms of swine influenza are similar to normal influenza (fever, cough, tiredness, muscle aches, sore throat, chills, shortness of breath, runny nose, headache). Some cases of swine influenza have also complained of vomiting and diarrhoea. In some cases, swine influenza can result in a severe pneumonia. Symptoms of influenza generally appear between two to four days after exposure.
· Who is at risk?
Currently, travellers exposed to cases of swine influenza overseas are at risk of becoming infected with the new swine influenza virus.
· How is it prevented?
As the new swine influenza strain has only been identified recently, a human vaccine for swine influenza is not yet available. Existing vaccines for normal human influenza will probably not provide protection against swine influenza. Scientists worldwide are working to develop a suitable human vaccine against swine influenza A (H1N1), however a vaccine is not expected to become available in the near future.
Until a vaccine becomes available, the best method of prevention will be to ensure that everyone washes their hands regularly and thoroughly, steps away from others when they cough or sneeze, coughs or sneezes into tissues and stays away from people who are sick.
· What should I do if I develop symptoms?
People who develop influenza-like symptoms should stay at home until they are completely better. People who have recently returned from affected areas and who develop influenza-like symptoms or breathing difficulties should contact their local public health unit, general practitioner or emergency department.
Swine influenza virus infection can be diagnosed using swabs from the nose and throat. Testing is done at a specialized laboratory.
· How is it treated?
If you become unwell and suspect that you may have swine influenza, you should contact your local public health unit or general practitioner, or go to your nearest hospital emergency department for assessment and treatment. Specific anti-influenza drugs are likely to be effective against swine influenza.
· What is the public health response?
There have been no confirmed cases of swine influenza in Australia as of 27 April 2009. There is enhanced surveillance for people infected with swine influenza, especially in people who have returned from affected areas within the last 7 days.
Should suspected human cases occur in NSW, the local public health unit will work with the patient, the treating doctors, and the laboratory to confirm the diagnosis. Suspected cases will be asked to isolate themselves from others to prevent further infection.
The situation is changing rapidly. For updated information on affected areas, see the Pakistani / Indian Government travel advice websites. Always wash your hands thoroughly after coming into contact with sick people, after coughing, sneezing or going to the toilet, or before eating.
How swine flu spreads in humans
Here are some facts from the U.S. Centers for Disease Control and Prevention about how swine flu spreads in humans:
* Swine flu viruses typically cause illness in pigs, not humans. Most cases occur when people come into contact with infected pigs or contaminated objects moving between people and pigs.
* Pigs can catch human and avian or bird flu. When flu viruses from different species infect pigs, they can mix inside the pig and new, mixed viruses can emerge.
* Pigs can pass mutated viruses back to humans, and these can be passed from human to human. Transmission among humans is thought to occur in the same way as with seasonal flu — by touching something contaminated with flu viruses and then touching one’s mouth or nose, and through coughing or sneezing. One of the most effective prevention measures is regular hand washing.
* Symptoms of swine flu in people are similar to those of seasonal influenza — sudden fever, coughing, muscle aches and extreme fatigue. This new strain also appears to cause more diarrhea and vomiting than normal flu.
* Vaccines are available to be given to pigs to prevent swine influenza. There is no vaccine to protect humans from swine flu, although the CDC is formulating one. The seasonal influenza vaccine may help to provide partial protection against swine H3N2, but not against swine H1N1 viruses like the one circulating now.
* People cannot catch swine flu from eating pork or pork products. Cooking pork to an internal temperature of 160 degrees Fahrenheit (71 degrees Celsius) kills the swine flu virus along with other bacteria and viruses.
Flu spreads silently, causes vague symptoms
A new strain of influenza has killed 103 people in Mexico and spread across North America and possibly as far afield as Spain and New Zealand. No one is certain about how virulent the virus is — meaning how severe the symptoms are — or what its patterns of transmission are.
Here are some facts about influenza in general, its symptoms and how it is transmitted.
* “Influenza” refers to a family of viruses that include influenza A, influenza B and influenza C.
* Symptoms include sudden onset of fever, muscle aches, headaches, cough and sometimes diarrhea and vomiting. Flu feels far more severe than a cold.
* People can pass flu along before they feel ill and after they feel better. Flu viruses can be found not only in nasal secretions but in fecal matter.
* The “incubation period” for flu — the time it takes from infection before symptoms develop — is usually about 24 to 48 hours, although it is not clear what the case is for this new H1N1 swine flu virus.
* The virus can be transmitted on particles of saliva and mucus when people cough and sneeze close to one another. Experts generally agree that three feet (1 meter) is the distance these particles can travel between people.
* Flu viruses can also live for days or even weeks on dry surfaces. More and more evidence shows that people very frequently infect themselves by touching a contaminated surface, such as a computer keyboard, and then touching the nose, eyes or mouth.
* Flu viruses evolve, or mutate, constantly. New strains emerge regularly, which is why the annual flu vaccine must be reformulated every year.
* Flu viruses are believed all to originate in animals. Little changes or mutations in the DNA can allow them to more easily infect people. Some cause more serious symptoms than others.
* Flu viruses are frequently deadly. The World Health Organization estimates that flu kills 250,000 to 500,000 people in a normal year, more during pandemics, which last occurred in 1968, 1957 and 1918.
* Flu can kill directly by causing pneumonia, and it can also make people more vulnerable to bacterial infections that also kill.
Some facts about pandemic flu from the WHO
The U.N. World Health Organization has said it is closely monitoring an outbreak of a new deadly strain of swine flu in Mexico and the United States.
The human-to-human spread of the virus has raised fears of a flu pandemic. The WHO has said it needs more information before it changes its pandemic alert level, currently at three on a scale of one to six.
Here are some facts about pandemic influenza from the WHO’s website http:/www.who.int/csr/disease/influenza/pandemic10things/en/
* Flu pandemics are caused by new flu viruses that adapt into strains that become contagious between humans.
* Flu pandemics occurred three times in the past century: the Hong Kong flu in 1968, the Asian flu in 1957 and the Spanish flu of 1918.
* Experts agree that another pandemic could come at any time and could involve any one of a number of new strains of flu. Most eyes have been on the H5N1 strain of avian flu that first infected people in Hong Kong in 1997. Since 2003 it has infected 421 people in 15 countries and killed 257 of them.
* To be declared a pandemic strain, a virus must be new to humans, cause serious illness, be easily transmitted from one person to another, and sustain that transmission efficiently.
* All countries will be affected once a fully contagious pandemic virus emerges. Previous pandemics circled the globe in six to nine months, even before international air travel was common. Today, a virus could reach all continents in weeks.
* Widespread illness will occur. Most people will have no immunity to the pandemic virus. A substantial percentage of the world’s population will need medical care, but few countries have enough staff, facilities, equipment and hospital beds.
* Supplies of vaccines and antiviral drugs will be inadequate. Many developing countries will have no access to vaccines.
* Many people will die. Based on the 1957 pandemic, the WHO conservatively estimates 2 million to 7.4 million people may die during the next outbreak, but says all estimates are speculative, and will depend on how many people become infected and the virulence of the virus, among other factors.
* Economic and social disruption will be great. High rates of worker absenteeism will impair services like power, transportation and communications.
* Every country must be prepared. The WHO has issued a series of recommended responses to the pandemic threat.
* The WHO will alert the world when the pandemic threat increases, working closely with governments and public health organizations on surveillance. WHO experts say it is too soon now to declare another pandemic.
Making a flu vaccine can take months
The U.N. World Health Organization and U.S. Centers for Disease Control and Prevention have been collecting samples of the new H1N1 swine flu virus to make a new vaccine in case it is needed.
Following are some facts about influenza vaccines.
* The WHO and CDC prepare samples of virus to give to industrial makers.
* These samples must be grown in specially produced chicken eggs. The virus is then purified and made into vaccines, a process that takes months.
* At least 20 companies make flu vaccines including Sanofi Pasteur, Australia’s CSL Ltd, GlaxoSmithKline Plc, Novartis AG, Baxter and nasal spray maker MedImmune, acquired by AstraZeneca Plc.
* Experts agree the current process for making vaccines is clumsy and outdated, but new and more efficient technologies are still a few years away.
* WHO and CDC experts are trying to decide if a new vaccine for the H1N1 swine flu strain is needed, or perhaps if a fourth element could be added to the seasonal flu vaccine mix for next September.
* The health agencies also had been considering adding some vaccines against H5N1 avian influenza, which occasionally infects people and is also considered a major pandemic threat.
* Tests show the H1N1 component of the current seasonal flu vaccine does not protect against the new strain.
* Consulting firm Oliver Wyman found that drug companies would need four years to meet global demand for vaccines if a pandemic broke out today, but new technology could significantly boost production by 2014.
* Currently, drug makers could make up to 2.5 billion doses of pandemic vaccines in one year, meaning it would take four years to meet global demand, Oliver Wyman found. In a best-case scenario, they could make 7.7 billion doses in 1.5 years.
* Compounds called adjuvants can be used to boost a vaccine’s effectiveness, so it could be diluted and used in more people.
* Current global demand for seasonal influenza vaccine is about 500 million doses a year.
* The CDC recommends that 261 million Americans — 85 percent of the population — should be vaccinated against flu. A RAND Corp. study in December showed that only about a third of those who should have did get the vaccine.
WHO warns swine flu threatening to become pandemic
Global health authorities warned Wednesday that swine flu was threatening to bloom into a pandemic, and the virus spread farther in Europe even as the outbreak appeared to stabilize at its epicenter. A toddler who succumbed in Texas became the first death outside Mexico. New cases and deaths finally seemed to be leveling off in Mexico, where 160 people have been killed, after an aggressive public health campaign.
But the World Health Organization said the global threat is nevertheless serious enough to ramp up efforts to produce a vaccine against the virus.
“It really is all of humanity that is under threat during a pandemic,” WHO Director General Margaret Chan said in Geneva. “We do not have all the answers right now, but we will get them.”
It was the first time the WHO had declared a Phase 5 outbreak, the second-highest on its threat scale, indicating a pandemic could be imminent.
The first U.S. death from the outbreak was a Mexico City toddler who traveled to Texas with family and died Monday night at a Houston hospital. U.S. Health and Human Services Secretary Kathleen Sebelius predicted the child would not be the last U.S. death from swine flu.
The virus, a mix of pig, bird and human genes to which people have limited natural immunity, had spread to at least nine countries. In the United States, nearly 100 have been sickened in 11 states.
Eight states closed schools Wednesday, affecting 53,000 students in Texas alone, and President Barack Obama said wider school closings might be necessary to keep crowds from spreading the flu. Mexico has already closed schools nationwide until at least May 6.
“Every American should know that the federal government is prepared to do whatever is necessary to control the impact of this virus,” Obama said, highlighting his request for $1.5 billion in emergency funding for vaccines.
Just north of the Mexican border, 39 Marines were being confined to their California base after one contracted what may be swine flu. Senators questioned Homeland Security Secretary Janet Napolitano about her decision not to close the border, action she said “has not been merited by the facts.”
Ecuador joined Cuba and Argentina in banning travel either to or from Mexico, and other nations considered similar bans. In France, President Nicolas Sarkozy met with cabinet ministers to discuss swine flu, and the health minister said France would ask the European Union to suspend flights to Mexico.
The U.S., the European Union and other countries have discouraged nonessential travel to Mexico. Some countries have urged their citizens to avoid the United States and Canada as well. Health officials said such bans would do little to stop the virus.
Germany and Austria became the latest countries to report swine flu infections Wednesday, with cases already confirmed in Canada, Britain, Israel, New Zealand and Spain.
In addition to the 160 deaths, the virus is believed to have sickened 2,498 people across Mexico. But only 1,311 suspected swine flu patients remained hospitalized, and a closer look at daily admissions and deaths at Mexico’s public hospitals suggests the outbreak may have peaked during three grim days last week when thousands of people complained of flu symptoms.
Scientists believe that somewhere in the world, months or even a year ago, a pig virus jumped to a human and mutated, and has been spreading between humans ever since. Unlike with bird flu, doctors have no evidence suggesting a direct pig-to-human infection from this strain, which is why they haven’t recommended killing pigs.
Medical detectives have not zeroed in on where the outbreak began. One of the seven deaths in Mexico directly attributed to swine flu was that of a Bangladeshi immigrant, said Mexico’s chief epidemiologist, who suggested that someone could have brought the virus from Pakistan or Bangladesh.
Miguel Angel Lezana, the epidemiologist, said the unnamed Bangladeshi had lived in Mexico for six months and was recently visited by a brother who arrived from Bangladesh or Pakistan and was reportedly ill. The brother has left Mexico and his whereabouts are unknown, Lezana said.
By March 9, the first symptoms were showing up in the Mexican state of Veracruz, where pig farming is a key industry in mountain hamlets and where small clinics provide the only health care.
The earliest confirmed case was there: a 5-year-old boy who was one of hundreds of people in the town of La Gloria whose flu symptoms left them struggling to breathe.
Days later, a door-to-door tax inspector was hospitalized with acute respiratory problems in the neighboring state of Oaxaca, infecting 16 hospital workers before she became Mexico’s first confirmed death.
Neighbors of the inspector, Maria Adela Gutierrez, said Wednesday that she fell ill after pairing up with a temporary worker from Veracruz who seemed to have a very bad cold. Other people from La Gloria kept going to jobs in Mexico City despite their illnesses, and could have infected people in the capital.
The deaths were already leveling off by the time Mexico announced the epidemic April 23. At hospitals Wednesday, lines of anxious citizens seeking care for flu symptoms dwindled markedly.
The Mexicanhealth secretary, Jose Angel Cordova, said getting proper treatment within 48 hours of falling ill “is fundamental for getting the best results” and said the country’s supply of medicine was sufficient.
Cordova has suggested the virus can be beaten if caught quickly and treated properly. But it was neither caught quickly nor treated properly in the early days in Mexico, which lacked the capacity to identify the virus, and whose health care system has become the target of widespread anger and distrust.
In case after case, patients have complained of being misdiagnosed, turned away by doctors and denied access to drugs. Monica Gonzalez said her husband, Alejandro, already had a bad cough when he returned to Mexico City from Veracruz two weeks ago and soon developed a fever and swollen tonsils.
As the 32-year-old truck driver’s symptoms worsened, she took him to a series of doctors and finally a large hospital. By then, he had a temperature of 102 and could barely stand.
“They sent him away because they said it was just tonsillitis,” she said. “That hospital is garbage.”
That was April 22, a day before Mexico’s health secretary announced the swine flu outbreak. But the medical community was already aware of a disturbing trend in respiratory infections, and Veracruz had been identified as a place of concern.
Gonzalez finally took her husband to Mexico City’s main respiratory hospital, “dying in the taxi.” Doctors diagnosed pneumonia, but it may have been too late: He has suffered a collapsed lung and is unconscious. Doctors doubt he will survive.
Swine flu has symptoms nearly identical to regular flu — fever, cough and sore throat — and spreads like regular flu, through tiny particles in the air, when people cough or sneeze. People with flu symptoms are advised to stay at home, wash their hands and cover their sneezes.
While epidemiologists stress it is humans, not pigs, who are spreading the disease, sales have plunged for pork producers around the world. Egypt began slaughtering its roughly 300,000 pigs on Wednesday, even though no cases have been reported there. WHO says eating pork is safe, but Mexicans have even cut back on their beloved greasy pork tacos.
Pork producers are trying to get people to stop calling the disease swine flu, and Obama notably referred to it Wednesday only by its scientific name, H1N1. U.N. animal health expert Juan Lubroth noted some scientists say “Mexican flu” would be more accurate, a suggestion already inflaming passions in Mexico.
Authorities have sought to keep the crisis in context. In the U.S. alone, health officials say about 36,000 people die every year from flu-related causes.
Mexico’s government said it remains too early to ease restrictions that have shut down public life in the overcrowded capital and much of the country. Pyramids, museums and restaurants were closed to keep crowds from spreading contagion.
“None of these measures are popular. We’re not looking for that — we’re looking for effectiveness,” Mexico City Mayor Marcelo Ebrard said. “The most important thing to protect is human life.”
Associated Press writers Olga Rodriguez in Oaxaca, Mexico, E. Eduardo Castillo in Mexico City, Lauran Neergaard and Tom Raum in Washington, Juan A. Lozano in Houston, Mike Stobbe in Atlanta, Patrick McGroarty in Berlin and Maamoun Youssef in Cairo contributed to this report.