Study: Swine Flu Resembles 1918 Virus
Monday, July 13, 2009
WASHINGTON — The new H1N1 influenza virus bears a disturbing resemblance to the virus strain that caused the 1918 flu pandemic, with a greater ability to infect the lungs than common seasonal flu viruses, researchers reported on Monday.
Tests in several 
animals
confirmed other studies that have shown the new swine flu strain can spread beyond the upper respiratory
tract to go deep into the lungs —
making it more likely to cause pneumonia, the international team said.
In addition, they found that people who survived the 1918 pandemic seem to have extra immune protection against the virus, again confirming the work of other researchers.
"When we conducted the experiments in ferrets and monkeys, the seasonal virus did not replicate in the lungs," said Yoshihiro Kawaoka of the University of Wisconsin, who led the study.
The H1N1 virus replicates significantly better in the lungs."
The new swine flu virus has caused the first pandemic of the 21st century, infecting more than a million people, according to estimates, and killing at least 500. The World Health Organization says it is causing mostly moderate disease but Kawaoka said that does not mean it is like seasonal flu.
"There is a misunderstanding about this virus," he said in a statement. "There is clear evidence the virus is different than seasonal influenza."
Writing in the journal Nature, Kawaoka and colleagues noted that the ability to infect the lungs is a characteristic of other pandemic viruses, especially the 1918 virus, which is estimated to have killed between 40 million and 100 million people.
Old Protection
They tested the virus in blood samples taken from nursing home residents and workers in 1999 in California, Wisconsin, the Netherlands and Japan.
People born before 1920 had a strong antibody response to the new H1N1 virus, meaning their body "remembered" it from infection early in life. This finding supports a study published in Nature in August that also found people who survived the 1918 pandemic still had immune protection against that virus.
Flu viruses change constantly, which is why people can be re-infected and why the vaccine must be changed regularly. Current seasonal strains of H1N1 are distant cousins of both the 1918 pandemic strain and the new H1N1 strain.
"Our findings are a reminder that swine-origin influenza viruses have not yet garnered a place in history, but may still do so, as the pandemic caused by these viruses has the potential to produce a significant impact on human health and the global economy," the researchers wrote.
Other tests showed the virus could be controlled by the antiviral drugs Relenza, made by GlaxoSmithKline, and Tamiflu, made by Roche AG, the researchers said.
The World Health Organization said on Monday that vaccine makers should start making immunizations against H1N1 and that healthcare workers should be first in line to get them.
Companies working on an H1N1 vaccine include Sanofi-Aventis, Novartis AG, Baxter International Inc, GlaxoSmithKline, Solvay and nasal spray maker MedImmune, now part of AstraZeneca.
H1N1 INFLUENZA VIRUS RESEMBLES VIRUS STRAIN CAUSING 1918 FLU PANDEMIC
IMR JADI MAKMAL RUJUKAN SELESEMA KHINZIR DI MALAYSIA
IMR telah bersiap sedia untuk menerima spesimen kes selesema babi, sebagai makmal rujukan dan ini juga merupakan salah satu daripada langkah pencegahan dan kawalan. Langkah-langkah lain seperti di bawah. Untuk jenis ujian DIAGNOSTIK SILA lihat di bawah.
CIRI-CIRI selesema khinzir
Hidung berair atau tersumbat
Sakit tekak
batuk dan demam
sakit-sakit tubuh badan
Sakit kepala
Seram sejuk atau mengigil apabila terkena air, kelesuan, cirit atau muntah
IMR Makmal Rujukan Selesema Babi
Mesyuarat Jawatankuasa Teknikal Influenza Pandemik melibatkan pelbagai agensi kerajaan yang bermesyuarat semalam telah mengiktiraf Institut Penyelidikan Perubatan (IMR) sebagai makmal rujukan bagi selesema babi.
"Langkah mengenal pasti IMR, yang bersiap sedia menerima spesimen kes selesema babi, sebagai makmal rujukan merupakan satu daripada langkah pencegahan dan kawalan yang dilakukan kerajaan," kata Ketua Pengarah Kesihatan Tan Sri Dr Mohd Ismail Merican (foto) dalam kenyataan Khamis.
Pandemik yang menular di sembilan negara termasuk United Kingdom, Amerika Syarikat dan Kanada, telah ditingkatkan dari Fasa 4 ke Fasa 5 oleh Pertubuhan Kesihatan Sedunia (WHO) semalam.
"Pengisytiharan Fasa 5 adalah isyarat jelas bahawa virus yang mengancam nyawa ini berkemungkinan besar menyebabkan pandemik pada bila-bila masa sahaja dan masa yang masih ada untuk melengkapkan persediaan daripada segi organisasi, komunikasi dan perlaksanaan pelan tindakan pengurangan risiko adalah sangat singkat," katanya.
Beliau berkata Bahagian Kawalan Penyakit Kementerian Kesihatan dan Jabatan Kesihatan Negeri telah mengaktifkan Bilik Gerakan untuk memantau situasi wabak dengan WHO bagi memastikan tindakan proaktif diambil untuk melindungi penduduk Malaysia.
Antara langkah lain yang akan dilakukan ialah meningkatkan tahap waspada semua jabatan kesihatan kerajaan dan swasta; pemberian vaksin influenza bermusim kepada anggota bertugas di barisan hadapan;
Yang turut ditingkatkan tahap kewaspadaan dan persediaan ialah 28 hospital yang dikenal pasti untuk menerima kes selesema babi, memastikan proses penghantaran vaksin di sembilan pusat simpanan stok antiviral di seluruh negara berjalan lancar;
Saringan kesihatan di semua pintu masuk antarabangsa; kerjasama Kementerian Penerangan, Komunikasi dan Kebudayaan dan Kementerian Kesihatan; dan peningkatan pemantauan Jabatan Perkhidmatan Haiwan di ladang ternakan babi termasuk menyuntik vaksin.
Setakat ini tiada kes selesema babi dilaporkan di negara ini.
Seorang pesakit yang disyaki menghidap jangkitan itu telah diperiksa oleh IMR semalam dan laporan kesihatan menunjukkannya negatif daripada wabak itu, kata Dr Mohd Ismail.
BERNAMA
------------------------------------------------------------------------------------
What Is the Clinical Presentation of Swine Flu?
Persons infected with swine flu may appear similar to those with seasonal influenza, presenting with symptoms of acute respiratory illness. Symptoms include at least 2 of the following:
Rhinorrhea or nasal congestion;
Sore throat;
Cough; and
Fever.
In addition, persons with swine flu may have other typical symptoms of influenza, including body aches, headache, chills, fatigue, and possibly diarrhea and vomiting.
Who Is Most at Risk for Swine Flu?
The CDC recommends that clinicians particularly consider the possibility of swine influenza A (H1N1) virus infection in patients with fevers and respiratory symptoms who:
Live in areas in the United States with confirmed human cases of swine influenza A (H1N1) virus infection. (To find the most up-to-date information on areas with confirmed swine influenza cases, go to http://www.cdc.gov/swineflu/index.htm)
Traveled recently to Mexico or were in contact with persons who had febrile respiratory illness and were in areas of the United States with confirmed swine influenza cases or Mexico in the 7 days preceding illness onset.
In addition, a person with an acute respiratory illness who has a recent history of contact with an animal with confirmed swine influenza should also be suspected (http://www.cdc.gov/swineflu/recommendations.htm). What Is the Range of Illness Severity Seen With Swine Flu?
Many cases of swine flu may be mild or even asymptomatic. In the past, cases were identified by chance as part of regular seasonal influenza surveillance. Most of the recent cases seen in the United States thus far have been mild as well. However, in Mexico, many patients' illnesses have been much more severe, have presented in young adults, and have included pneumonia, respiratory failure, and acute respiratory distress syndrome. Illness-related fatalities have been recorded in Mexico. At this time, it is not clear why such differences in illness severity have been seen. Early in epidemics it is difficult to gauge severity because the overall denominator of people infected is unknown.
How Should Swine Flu Be Diagnosed?
Preferred specimens. If swine flu is suspected, clinicians should obtain a respiratory specimen for analysis. In an ideal situation, the best method is via nasal pharyngeal aspirate or nasal wash aspirate into viral culture media; however, some experts are recommending the use of Dacron nasal swabs to decrease aerosolization of the virus. If these specimens cannot be collected, a combined nasal swab with an oropharyngeal swab is also acceptable and will be feasible in most settings. (Ideally, swab specimens should be collected using swabs with a synthetic tip and an aluminum or plastic shaft. Swabs with cotton tips and wooden shafts are not recommended. Specimens collected with swabs made of calcium alginate are not acceptable.)
The specimen should be placed in a 4°C refrigerator (not a freezer) or immediately placed on ice or cold packs for transport to the laboratory. Once collected, make contact with the state or local health department to facilitate transport and timely diagnosis at a state public health laboratory.
Recommended tests. The CDC currently recommends "real-time RT-PCR for influenza A, B, H1, H3 conducted at a State Health Department Laboratory. Currently, swine influenza A (H1N1) virus will test positive for influenza A and negative for H1 and H3 by real-time RT-PCR. If reactivity of real-time RT-PCR for influenza A is strong (e.g., Ct ≤ 30) it is more suggestive of a novel influenza A virus." Confirmation as swine influenza A (H1N1) virus is now performed at the CDC but may be available in state public health laboratories soon.
Rapid influenza testing. Rapid testing for swine flu likely is similar to that for seasonal flu, meaning that sensitivities range between 50% and 70% of cases (no better than using fever and cough as a marker in a patient during influenza season), depending on the manufacturer. Therefore, negative rapid tests should not indicate a lack of influenza. (For general guidance on rapid influenza testing, see http://www.cdc.gov/flu/professionals/diagnosis/rapidlab.htm)
Rapid tests can distinguish between influenza A and B viruses. A patient with a positive rapid test for influenza A may meet criteria for a probable case of swine flu, but again, a negative rapid test could be a false negative and should not be assumed a final diagnostic test for swine influenza infection.
Other tests.
Immunofluorescence (DFA or IFA) tests can distinguish between influenza A and B viruses. A patient who is positive for influenza A by immunofluorescence may meet criteria for a probable case of swine influenza. However, a negative immunofluorescence could be a false negative and should not be assumed a final diagnostic test for swine influenza infection.
Isolation of swine influenza A (H1N1) virus by viral culture is also diagnostic of infection but may not yield timely results for clinical management. A negative viral culture does not exclude infection with swine influenza A (H1N1) virus.
To stay up-to-date on the latest recommendations for testing, check regularly at: http://www.cdc.gov/swineflu/specimencollection.htm
SWINE FLU H1N1 VS AVIAN FLU H5N1(sars)
Infection control experts are scrambling to respond to outbreaks of swine flu in Mexico and the US, and suspected cases elsewhere.
What is swine flu?
Swine flu is a respiratory disease which infects pigs.
Caused by influenza type A, there are regular outbreaks among herds of pigs, where the disease causes high levels of illness but is rarely fatal.
It tends to spread in autumn and winter but can circulate all year round.
There are many different types of swine flu and like human flu, the infection is constantly changing.
Can humans catch swine flu?
Swine flu does not normally infect humans, although sporadic cases do occur - usually in people who have had close contact with pigs.
There have also been rare documented cases of humans passing the infection to other humans.
Human-to-human transmission of swine flu is thought to spread in the same way as seasonal flu - through coughing and sneezing.
In the latest outbreak it is clear that the disease is being passed from person to person.
Symptom of swine flu in humans appear to be similar to those produced by standard, seasonal flu.
Is this a new type of swine flu?
The World Health Organization has confirmed that at least some of the 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.
Is it safe to eat pig meat?
Yes. There is no evidence that swine flu can be transmitted through eating meat from infected animals.
However, it is essential to cook meat properly. A temperature of 70C (158F) would be sure to kill the virus.
How worried should people be?
When any new strain of flu emerges that acquires the ability to pass from person to person, it is monitored very closely in case it has the potential to spark a pandemic.
FLU PANDEMICS
1918: The Spanish flu pandemic remains the most devastating outbreak of modern times. Caused by a form of the H1N1 strain of flu, it is estimated that up to 40% of the world's population were infected, and more than 50 million people died, with young adults particularly badly affected
1957: Asian flu killed two million people. Caused by a human form of the virus, H2N2, combining with a mutated strain found in wild ducks. The impact of the pandemic was minimised by rapid action by health authorities, who identified the virus, and made vaccine available speedily. The elderly were particularly vulnerable
1968: An outbreak first detected in Hong Kong, and caused by a strain known as H3N2, killed up to one million people globally, with those over 65 most likely to die
The World Health Organization has warned that taken together the Mexican and US cases could potentially trigger a global pandemic, and stress that the situation is serious.
However, it is stressed that it is still too early to accurately assess the situation fully.
Currently, they say the world is closer to a flu pandemic than at any point since 1968 - rating the threat at three on a six-point scale.
Nobody knows the full potential impact of the pandemic, but experts have warned that it could cost millions of lives worldwide. The Spanish flu pandemic, which began in 1918, and was also caused by an H1N1 strain, killed millions of people.
The fact that all the cases in the US have so far produced mild symptoms is encouraging. It suggests that the severity of the Mexican outbreak may be due to an unusual geographically-specific factor - possibly a second unrelated virus circulating in the community - which would be unlikely to come into play in the rest of the world.
However, the fact that many of the victims are young does point to something unusual. Normal, seasonal flu tends to affect the elderly disproportionately.
What about treatments and vaccines?
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.
It is unclear how effective currently available flu vaccines would be at offering protection against the new strain, as it is genetically distinct from other flu strains.
US scientists are already developing a bespoke new vaccine, but it may take some time to perfect it, and manufacture enough supplies to meet what could be huge demand.
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.
UK monitoring swine flu outbreak
Dr John Watson, Health Protection Agency: 'The UK must be prepared'
Health officials in the UK say they are monitoring closely a deadly outbreak of swine flu in Mexico, amid fears of a potential pandemic.
The Health Protection Agency (HPA) said it was working with the government to assess any threat posed to the public.
It described the outbreak as "unusual" and warranting "further investigation and vigilance" by other countries.
Northwick Park Hospital said a BA worker who arrived from Mexico City and fell ill does not have swine flu.
At least 81 people in Mexico are now thought to have died after contracting a new strain of flu being linked to an outbreak of swine flu in the US.
There have been no confirmed cases so far in Europe.
1. Is this a flu pandemic?
The influenza virus is constantly mutating. That's why we can't get full immunity to the flu, the way we can to diseases like chicken pox, because there are multiple strains of the flu virus and they change from year to year. However, even though the virus makes us sick, our immune systems can usually muster enough of a response so that the flu is rarely fatal for healthy people.
But every once in awhile, the virus shifts its genetic structure so much that our immune systems offer no protection whatsoever. (This usually happens when a flu virus found in animals — like the avian flu still circulating in Asia — swaps genes with other viruses in a process called reassortment, and jumps to human beings.) A flu pandemic occurs when a new flu virus emerges for which humans have little or no immunity and then spreads easily from person to person around the world. In the 20th century we had two mild flu pandemics, in 1968 and 1957, and the severe "Spanish flu" pandemic of 1918, which killed an estimated 40 to 50 million people worldwide.
The WHO has the responsibility of declaring when a new flu pandemic is underway, and to simplify the process, the U.N. body has established six pandemic phases. Thanks to H5N1 avian flu, which has killed 257 people since 2003 but doesn't spread very well from one human to another, we're currently at phase 3. If the WHO upgraded that status to phase 4, which is marked by a new virus that begins to pass easily enough from person to person that we can detect community-sized outbreaks, such a move would effectively mean that we've got a pandemic on our hands.
The H1N1 swine flu virus has already been identified as a new virus, with genes from human and avian flus as well as the swine variety. And since it is apparently causing large-scale outbreaks in Mexico, along with separate confirmed cases in the U.S. and Canada and suspected cases in other countries, it would seem that we've already met the criteria for phase 4. But though an emergency committee met on April 25 to evaluate the situation, the WHO hasn't made the pandemic declaration yet. Keiji Fukuda, the WHO's interim assistant director-general for health, security and environment, said on Sunday that its experts "would like a little bit more information and a little bit more time to consider this." The committee is set to meet again by April 28 at the latest.
As health officials have repeatedly emphasized, with good reason, the swine flu situation is evolving rapidly, and more lab tests are needed to ascertain exactly what is going on in Mexico and elsewhere. "We want to make sure we're on solid ground," said Fukuda, a highly respected former CDC official and flu expert.
Swine Flu: 5 Things You Need to Know About the Outbreak {HERE }
The Truth About SARS
