We are reeling under a surfeit of breaking news and scientific expert opinions about the swine flu pandemic. However, we need to remain focused and evaluate the statistics. The World Health Organization (WHO) says that there are approximately 1.2 million cases worldwide and around 1,000 deaths. In India, the fatalities are still in the double digits.
In contrast, tuberculosis (TB) causes 4,00,000 deaths in India annually. In fact, it is the leading cause of death in the economically productive 15 to 45 age group. However, TB can be easily diagnosed and cured with proper medication.
Around 450 out of 1,00,000 healthy young women die during childbirth. This is in contrast to China where the figure has fallen to 50. The WHO report states that the problem is magnified because the poor get inadequate care, while the rich demand and pay for caesarians and other non essential interventions.
Nineteen-year-old Saina Nehwal made headlines when she developed chicken pox a couple of weeks before the August 10 world badminton finals. She is part of the 95 per cent of the world population that develops chicken pox at some time in the course of their lives. It is an extremely contagious infection which is not taken seriously, as it usually results in innocuous disease. It can, however, turn dangerous and cause complications like brain fever, blindness, pneumonia and sterility in 10 per cent of those affected. If it occurs in childhood, it usually passes off with about a month’s absence from school. But if it occurs at a crucial stage in life like during your college finals or a public exam, it can cause much misery. The fact is such harassment is totally avoidable. The disease is preventable with a single dose of Varicella vaccine, which has to be administered after the age of one.
Pneumococcal disease causes pneumonia, brain fever, ear infection, sinusitis and bronchitis. The infection is common and results in 1.6 million deaths every year. Of this, one million are children. The death toll can be eliminated with timely immunisation in childhood. Infective jaundice because of hepatitis A and B can also be prevented with immunisation. Hepatitis A is considered harmless and exposure inevitable in India. Although the number of fatalities is negligible, it causes morbidity, with a feeling of “weakness”, lack of energy and ill health that persists for months. Hepatitis B is more dangerous. It can result in liver damage, chronic disease, cancer and even death. Again, both infections are preventable with immunisation.
Rubella or German measles is another disease that is preventable through vaccination. If acquired during pregnancy, the affliction can result in a stillbirth or a mentally retarded child with multiple defects requiring a lifetime of care. There are more vaccine preventable diseases such as measles, brain fever (caused by H. Influenzae or the meningococcal bacteria), typhoid, rotor virus diarrhoea, polio and even cervical cancer (caused by the Human Papillovirus infection).
Why then are we so focused on the swine flu epidemic? Flu has been around for centuries. Confirmed pandemics have been occurring with devastating regularity after 1918. The viruses responsible have a reservoir in birds and animals from where they mutate and transmigrate into humans. Since pigs share many genes with humans, the transition is this particular pandemic is very efficient. The rapid spread of the virus is helped by the lack of sunshine during the monsoon and in winter. It cannot survive long when exposed to our tropical sun, so in India the pandemic may be time bound.
It is difficult to differentiate the symptoms of regular flu from that of swine flu. Both start with fever, body ache, headache, sore throat, nasal stuffiness and cough. There may be diarrhoea or vomiting. The symptoms are more severe with swine flu. Most healthy people recover spontaneously from either. Those at risk are children under five, old people above 65, pregnant women and those with underlying medical conditions such as cancer, diabetes or heart disease.
Vaccines are available, but they have to be “upgraded” and “restructured” each time there is a new epidemic, as the genetic nature of the virus changes. The WHO anticipates that a vaccine to protect us against this pandemic will be available by October or November. But will there be enough vaccine to cover the entire world (or even Indian) population at risk?
The diagnosis is confirmed by tests done on nasal and throat swabs or nasal aspirates. Blood tests can be done but they take five days and involve taking two different samples. Treatment too is available in government hospitals. The drug Tamiflu (oseltamivir) is administered once diagnosis is confirmed.
The likelihood of infection is reduced by:
• Washing hands with soap several times a day, especially after handling money
• Cleaning surfaces like doorknobs with disinfectant
A new research has revealed the origins of swine flu after scientists discovered that the transmission of the H1N1influenza A virus to humans occurred several months before recognition of the existing outbreak.
In the new research, an international team, led by Oxford University, used evolutionary analysis to estimate the timescale of the origins as well as the early development
of the swine flu pandemic.
According to the scientists, the virus was actually derived from several viruses circulating in swine, and that the initial transmission to humans occurred several months before recognition of the outbreak.
Lead scientist Dr Oliver Pybus said, “Using computational methods, developed over the last ten years at Oxford, we were able to reconstruct the origins and timescale of this new pandemic.”
“Our results show this strain has been circulating among pigs, possibly among multiple continents, for many years prior to its transmission to humans.”
The research highlights the need for systematic surveillance of influenza in swine, and provides evidence that new genetic elements in swine can result in the emergence of viruses with pandemic potential in humans.
The scientists concluded that “despite widespread influenza surveillance in humans, the lack of systematic swine surveillance allowed for undetected persistence and evolution of this potentially pandemic strain for many years.”
The team included scientists from Oxford University, the University of Edinburgh, the University of Hong Kong and the University of Arizona. Their findings are published in the latest edition of the ‘Nature’ journal.
Governments in North America ignored warnings that a swine flu strain was circulating in pig farms.
Canadian paediatrician Joan Robinson’s long-planned holiday to Mexico wouldn’t have been jeopardised and the world may not have been teetering on the brink of a pandemic had authorities acted on her words of caution.
Robinson’s late-June vacation destination is at the centre of a potentially pandemic flu outbreak, which has now spread to 14 other countries in five continents, apart from reportedly killing 160 people since mid-April. Her government, like many others, has issued a travel advisory to avoid non-essential travel to Mexico for a while.
Ironically, Robinson, professor of paediatric infectious diseases at the University of Alberta, Canada, had warned as early as February 2008 that a swine flu strain capable of human-to-human transmission is circulating in North America, particularly in some Canadian pig farms.
No one knows whether it is the same flu strain that’s wreaking havoc now as flu viruses mutate notoriously fast. But had the authorities listened to her, the world wouldn’t have been caught by surprise.
Robinson got a whiff of the trouble brewing when a seven-month-old baby living on a community pig farm was diagnosed with a mild swine flu attack in 2006. Subsequently, her team screened 90 people, who lived on the farm, to find 54 of them positive to the strain. Her paper, in early 2008, called for monitoring pig farm workers in Canada and other countries as part of their national influenza pandemic preparedness plans.
“Countries did not take up any surveillance of swine workers, probably because the number of human swine flu symptomatic cases until 2009 was so small that experts did not think this was an important part of pandemic planning,” she told KnowHow. Early recognition of swine strains becoming virulent is key to infection control as well as vaccine development, she said.
Robinson wasn’t alone in waving the red flag. Gregory Gray, director of the Center for Emerging Infectious Diseases at the University of Iowa College of Public Health, reported in 2006 that some pig farmers and meat processing workers they studied had elevated levels of antibodies against swine flu in their blood — an indicator that they were exposed to the flu virus. More importantly, a team of researchers from St. Jude Children’s Research Hospital in Memphis picked up signals as early as 1998 that flu viruses in pigs were swapping their genetic material, triggering the possibility of newer — maybe more lethal — strains being in circulation.
Thanks to the H5N1avian flu outbreaks reported in different parts of the world since 2003, including India, the world is better prepared to deal with the emerging crisis. In less than a week of the outbreak being confirmed, the World Health Organization warned that a pandemic is imminent. “It is because of the concerns with the H5N1 virus that we have been able to pick up this outbreak relatively early, and we are much better prepared because of that,” said Michael Osterholm, who heads the Center for Infectious Disease Research and Policy at the University of Minnesota.
International public health experts have enough reasons to be alarmed.
For one, the influenza virus is very unpredictable. A flu strain may be harmless, but a slight change in its genetic composition can turn it into an extremely virulent variety. “The flu virus constantly surprises us,” said Nancy Cox who heads the flu division at the Center for Disease Control and Prevention (CDC) at Atlanta. The source of this surprise — not really a pleasant one though — is the ability flu viruses have to swap their genetic material when two or more of them co-habit. “Analysis of the early isolates suggests that the genetic make up of this new virus is a mixture of the avian, swine and human viral genomes. It is too early to tell how this virus evolved,” said Ram Sasisekharan, professor of biological engineering at Massachusetts Institute of Technology, US.
Then, the fact that the virus originated from pigs was the biggest worry for public health authorities. Pigs have been the ideal mixing vessel for flu viruses afflicting different species: humans, birds and pigs. While it is very rare for other species to accommodate more than one flu strain at any point in time, pigs do that happily, that too without being sick.
Further, the 1918 Spanish flu which killed anything between 50 million and 100 million across the globe too was of swine origin. The similarities, however, seem to end there. Though they are both H1N1 viruses, the novel swine flu does not appear to share any of the genetic markers of the virulence that 1918 pandemic flu virus possessed, according to a CDC statement.
But, there is one thing that makes virologists happy. Genetic analysis of the strains isolated from affected countries — Mexico, the US, New Zealand, Canada, the Netherlands and Germany — indicates that the strain has so far stayed steady, and hasn’t mutated. All genes of these strains have 99 per cent to 100 per cent similarity. This makes producing a vaccine easier, said Cox.
If that is true, the scientists may have to find why the same strain is behaving differently in two different populations. While the number of deaths in Mexico is frightening, there hasn’t been any serious case outside Mexico. While 159 people reportedly died in Mexico (but of these only sixteen are laboratory-confirmed swine flu deaths), there was only one death outside: in the US.
What, however, is puzzling is that the 159 deaths have come from some 2,500 cases reported in Mexico, pointing to a very high fatality rate (the ratio between number of cases and deaths). The Mexican government has stopped reporting suspected cases and deaths since April 30, 2009.
Some of the questions scientists already asking are: Is this because a huge number of Mexicans have been infected? Is that because many of the deaths in Mexico are due to other causes, since only a minority of the people who died were actually tested for swine flu? Is that because Hispanic people have a different response to this virus than white people do? Is that because Mexicans were more likely to be infected by a household member and most others were infected by more casual contact, and so got a smaller dose of the virus? How capable is this virus of efficiently spreading from person to person multiple times?
“Until we have answers to some of these questions, we do not know if the current outbreak will be over shortly (the 1976 US swine flu outbreak lasted 21 days) or will ultimately prove to be a pandemic,” said Robinson.
According to Wendy Barclay, a flu virologist at the Imperial College in London, the outbreak in Mexico may not have such a high case fatality rate. “We don’t know how many people may have been infected but didn’t get very ill,” he says. Every normal pandemic has a case fatality rate of 1 to 2 per cent. “This is the type of figure that governments should have planned for in any pandemic,” Barclay told KnowHow. “But anything beyond 5 per cent could be really bad.” Sources: The Telegraph (Kolkata, India)
Swine flu is common in swine and rare in humans. People who work with swine, especially people with intense exposures, are at risk of catching swine influenza if the swine carry a strain able to infect humans. However, these strains rarely are able to pass from human to human. Rarely, SIV mutates into a form able to pass easily from human to human. The strain responsible for the 2009 swine flu outbreak is believed to have undergone such a mutation. This virus is named swine flu because one of its surface proteins is similar to viruses that usually infects pigs, but this strain is spreading in people and it is unknown if it infects pigs.
It is an infection caused by any one of several types of swine influenza viruses. Swine influenza virus (SIV) or swine-origin influenza virus (S-OIV) is any strain of the influenza family of viruses that is endemic in pigs.As of 2009, the known SIV strains include influenza C and the subtypes of influenza A known as H1N1, H1N2, H2N1, H3N1, H3N2, and H2N3.
In humans, the symptoms of swine flu are similar to those of influenza and of influenza-like illness in general, namely chills, fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort. The strain responsible for the 2009 swine flu outbreak in most cases causes only mild symptoms and the infected person makes a full recovery without requiring medical attention and without the use of antiviral medicines.
Of the three genera of human flu, two are endemic also in swine: Influenzavirus A (common) and Influenzavirus C (rare). Influenzavirus B has not been reported in swine. Within Influenzavirus A and Influenzavirus C, the strains endemic to swine and humans are largely distinct.
The swine flu is likely a descendant of the infamous “Spanish flu” that caused a devastating pandemic in humans in 1918–1919. In less than a year, that pandemic killed more an estimated 50 million people worldwide. Descendants of this virus have persisted in pigs; they probably circulated in humans until the appearance of the Asian flu in 1957, and reemerged in 1977. Direct transmission from pigs to humans is rare, with 12 cases in the U.S. since 2005.
The flu virus is perhaps the trickiest known to medical science; it constantly changes form to elude the protective antibodies that the body has developed in response to previous exposures to influenza or to influenza vaccines. Every two or three years the virus undergoes minor changes. Then, at intervals of roughly a decade, after the bulk of the world’s population has developed some level of resistance to these minor changes, it undergoes a major shift that enables it to tear off on yet another pandemic sweep around the world, infecting hundreds of millions of people who suddenly find their antibody defenses outflanked. Even during the Spanish flu pandemic, the initial wave of the disease was relatively mild and the second wave was highly lethal.In 1957, an Asian flu pandemic infected some 45 million Americans and killed 70,000. Eleven years later, lasting from 1968 to
1969, the Hong Kong flu pandemic afflicted 50 million Americans and caused 33,000 deaths, costing approximately $3.9 billion.
In 1976, about 500 soldiers became infected with swine flu over a period of a few weeks. However, by the end of the month investigators found that the virus had “mysteriously disappeared” and there were no more signs of swine flu anywhere on the post. There were isolated cases around the U.S. but those cases were supposedly to individuals who caught the virus from pigs.
Medical researchers worldwide, recognizing that the swine flu virus might again mutate into something as deadly as the Spanish flu, were carefully watching the latest 2009 outbreak of swine flu and making contingency plans for a possible global pandemic.
Swine influenza virus is common throughout pig populations worldwide. Transmission of the virus from pigs to humans is not common and does not always lead to human flu, often resulting only in the production of antibodies in the blood. If transmission does cause human flu, it is called zoonotic swine flu. People with regular exposure to pigs are at increased risk of swine flu infection.
Around the mid-20th century, identification of influenza subtypes became possible, allowing accurate diagnosis of transmission to humans. Since then, only 50 such transmissions have been confirmed. These strains of swine flu rarely pass from human to human. Symptoms of zoonotic swine flu in humans are similar to those of influenza and of influenza-like illness in general, namely chills, fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort.
In August 2010, the World Health Organization declared the swine flu pandemic officially over.
Cases of swine flu have been reported in India, with over 31,156 positive test cases and 1,841 deaths till March 2015.
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)……click & see
Influenza viruses bind through hemagglutinin onto sialic acid sugars on the surfaces of epithelial cells; typically in the nose, throat and lungs of mammals and intestines of birds (Stage 1 in infection figure).
Swine flu in humans:
People who work with poultry and swine, especially people with intense exposures, are at increased risk of zoonotic infection with influenza virus endemic in these animals, and constitute a population of human hosts in which zoonosis and reassortment can co-occur. Transmission of influenza from swine to humans who work with swine was documented in a small surveillance study performed in 2004 at the University of Iowa. This study among others forms the basis of a recommendation that people whose jobs involve handling poultry and swine be the focus of increased public health surveillance. The 2009 swine flu outbreak is an apparent reassortment of several strains of influenza A virus subtype H1N1, including a strain endemic in humans and two strains endemic in pigs, as well as an avian influenza.
The CDC reports that the symptoms and transmission of the swine flu from human to human is much like that of seasonal flu. Common symptoms include fever, lethargy, lack of appetite and coughing, while runny nose, sore throat, nausea, vomiting and diarrhea have also been reported. It is believed to be spread between humans through coughing or sneezing of infected people and touching something with the virus on it and then touching their own nose or mouth. Swine flu cannot be spread by pork products, since the virus is not transmitted through food. The swine flu in humans is most contagious during the first five days of the illness although some people, most commonly children, can remain contagious for up to ten days. Diagnosis can be made by sending a specimen, collected during the first five days, to the CDC for analysis.
The swine flu is susceptible to four drugs licensed in the United States, amantadine, rimantadine, oseltamivir and zanamivir; however, for the 2009 outbreak it is recommended it be treated under medical advice only with oseltamivir and zanamivir to avoid drug resistance. The vaccine for the human seasonal H1N1 flu does not protect against the swine H1N1 flu, as they are antigenically very different.
The cause of the 2009 swine flu was an influenza A virus type designated as H1N1. In 2011, a new swine flu virus was detected. The new strain was named influenza A (H3N2)v. Only a few people (mainly children) were first infected, but officials from the U.S. Centers for Disease Control and Prevention (CDC) reported increased numbers of people infected in the 2012-2013 flu season. Currently, there are not large numbers of people infected with H3N2v. Unfortunately, another virus termed H3N2 (note no “v” in its name) has been detected and caused flu, but this strain is different from H3N2v. In general, all of the influenza A viruses have a structure similar to the H1N1 virus; each type has a somewhat different H and/or N structure.
Complications Of Swine Flu And Higher Risk Individuals:-
Those at higher risk include those with the following:
*Age of 65 years or older
*Chronic health problems (such as asthma, diabetes, heart disease)
Complications (for all patients but especially for those at higher risk) can include:
1. A respiratory sample collected within the first five days of illness will be collected.
2. The sample is sent to the CDC for laboratory analysis and confirmation.
At this time the CDC is recommending the use of oseltamivir (Tamiflu) or zanamivir (Relenza) for treatment and/or prevention of Swine flu.
Why is swine flu now infecting humans?
Many researchers now consider that two main series of events can lead to swine flu (and also avian or bird flu) becoming a major cause for influenza illness in humans.
First, the influenza viruses (types A, B, C) are enveloped RNA viruses with a segmented genome; this means the viral RNA genetic code is not a single strand of RNA but exists as eight different RNA segments in the influenza viruses. A human (or bird) influenza virus can infect a pig respiratory cell at the same time as a swine influenza virus; some of the replicating RNA strands from the human virus can get mistakenly enclosed inside the enveloped swine influenza virus. For example, one cell could contain eight swine flu and eight human flu RNA segments. The total number of RNA types in one cell would be 16; four swine and four human flu RNA segments could be incorporated into one particle, making a viable eight RNA-segmented flu virus from the 16 available segment types. Various combinations of RNA segments can result in a new subtype of virus (this process is known as antigenic shift) that may have the ability to preferentially infect humans but still show characteristics unique to the swine influenza virus . It is even possible to include RNA strands from birds, swine, and human influenza viruses into one virus if a single cell becomes infected with all three types of influenza (for example, two bird flu, three swine flu, and three human flu RNA segments to produce a viable eight-segment new type of flu viral genome). Formation of a new viral type is considered to be antigenic shift; small changes within an individual RNA segment in flu viruses are termed antigenic drift and result in minor changes in the virus. However, these small genetic changes can accumulate over time to produce enough minor changes that cumulatively alter the virus’ makeup over time (usually years).
Second, pigs can play a unique role as an intermediary host to new flu types because pig respiratory cells can be infected directly with bird, human, and other mammalian flu viruses. Consequently, pig respiratory cells are able to be infected with many types of flu and can function as a “mixing pot” for flu RNA segments . Bird flu viruses, which usually infect the gastrointestinal cells of many bird species, are shed in bird feces. Pigs can pick these viruses up from the environment, and this seems to be the major way that bird flu virus RNA segments enter the mammalian flu virus population.
Present vaccination strategies for SIV control and prevention in swine farms, typically include the use of one of several bivalent SIV vaccines commercially available in the United States. Of the 97 recent H3N2 isolates examined, only 41 isolates had strong serologic cross-reactions with antiserum to three commercial SIV vaccines. Since the protective ability of influenza vaccines depends primarily on the closeness of the match between the vaccine virus and the epidemic virus, the presence of nonreactive H3N2 SIV variants suggests that current commercial vaccines might not effectively protect pigs from infection with a majority of H3N2 viruses.
In response to requests from the U.S. Centers for Disease Control and Prevention, on April 27, 2009 the FDA issued Emergency Use Authorizations to make available diagnostic and therapeutic tools to identify and respond to the swine influenza virus under certain circumstances. The agency issued these EUAs for the use of certain Relenza and Tamiflu antiviral drugs, and for the rRT-PCR Swine Flu Panel diagnostic test.
The CDC recommends the use of Tamiflu (oseltamivir) or Relenza (zanamivir) for the treatment and/or prevention of infection with swine influenza viruses, however, the majority of people infected with the virus make a full recovery without requiring medical attention or antiviral drugs The virus isolates that have been tested from the US and Mexico are however resistant to amantadine and rimantadine. If a person gets sick, antiviral drugs can make the illness milder and make the patient feel better faster. They may also prevent serious flu complications. For treatment, antiviral drugs work best if started soon after getting sick (within 2 days of symptoms).
Some countries have issued orders to stockpile antivirals . These typically have an expiry date of five years after manufacturing.
To maintain a secure household during a pandemic flu, the Water Quality & Health Council recommends keeping as supplies food and bottled water, portable power sources and chlorine bleach as an emergency water purifier and surface sanitizer.
click & see Prevention of swine influenza has three components:-(1) prevention in swine, (2) prevention of transmission to humans, and (3) prevention of its spread among humans.
(1)Prevention in swine
Swine influenza has become a greater problem in recent decades as the evolution of the virus has resulted in inconsistent responses to traditional vaccines. Standard commercial swine flu vaccines are effective in controlling the infection when the virus strains match enough to have significant cross-protection, and custom (autogenous) vaccines made from the specific viruses isolated are created and used in the more difficult cases.
(2) Prevention of transmission to humans
There are antiviral medicines you can take to prevent or treat swine flu. There is no vaccine available right now to protect against swine flu. You can help prevent the spread of germs that cause respiratory illnesses like influenza by
*Covering your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it.
*Washing your hands often with soap and water, especially after you cough or sneeze. You can also use alcohol-based hand cleaners.
*Avoiding touching your eyes, nose or mouth. Germs spread this way.
*Trying to avoid close contact with sick people.
*Staying home from work or school if you are sick.
(3) Prevention of spread in humans
Recommendations to prevent spread of the virus among humans include using standard infection control against influenza. This includes frequent washing of hands with soap and water or with alcohol-based hand sanitizers, especially after being out in public. Vaccines against the H1N1 strain in the 2009 human outbreak are being developed and could be ready as early as June 2009.
Experts agree that hand-washing can help prevent viral infections, a surprisingly effective way to prevent all sorts of diseases, including ordinary influenza and the new swine flu virus. Influenza can spread in coughs or sneezes, but an increasing body of evidence shows little particles of virus can linger on tabletops, telephones and other surfaces and be transferred via the fingers to the mouth, nose or eyes. Alcohol-based gel or foam hand sanitizers work well to destroy viruses and bacteria. Anyone with flu-like symptoms such as a sudden fever, cough or muscle aches should stay away from work or public transportation and should see a doctor to be tested.
Social distancing is another tactic. It means staying away from other people who might be infected and can include avoiding large gatherings, spreading out a little at work, or perhaps staying home and lying low if an infection is spreading in a community.
Disclaimer: This information is not meant to be a substitute for professional medical advise or help. It is always best to consult with a Physician about serious health concerns. This information is in no way intended to diagnose or prescribe remedies.This is purely for educational purpose.
Scientists in Hong Kong and the United States have identified a synthetic compound which appears to be able to stop the replication of influenza viruses, including the H5N1 bird flu virus. …
The search for such new “inhibitors” has grown more urgent in recent years as drugs, like oseltamivir, have become largely ineffective against certain flu strains, like the H1N1 seasonal flu virus. Experts now question how well the drug would stand up against H5N1, should it unleash a pandemic.
Researchers in Hong Kong and the US found 20 compounds catalogued with the US National Cancer Institute that could potentially restrict the proliferation of the H5N1