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2009 swine flu pandemic

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Cases of this strain of swine flu by country or state.
Country or State Confirmed laboratory cases Other possible cases* Deaths from confirmed cases Deaths from possible cases*
Mexico 18[1] 1000+[2] 0 68[3]
California 7[4] 0 0 0
Texas 2[4] 1 0 0
Kansas 2[4] 0 0 0
New York 0 200[5] 0 0
United Kingdom 0 1[6] 0 0
Total 29 1200+ 0 68
(*) Not all cases are known for sure to have been caused by swine flu.

The outbreak of a new strain of Swine Influenza A (H1N1), in late March 2009 infected many people in Mexico City, other regions of Mexico, and parts of the United States, causing severe illness and death in Mexico. By April, the World Health Organization (WHO) and the U.S. Centers for Disease Control (CDC) [7] have both expressed serious concerns that the novel strain, which apparently transmits from human to human and which to date has had a relatively high mortality rate in the possible and confirmed Mexican cases, has the potential to become a flu pandemic.

Outbreak

Train commuters in Mexico City wearing surgical masks in an attempt to protect themselves from the swine flu. Masks cannot filter viruses, but they can protect from aerosols and fingers that carry viruses.

In March and April 2009, over 1000 cases of unusually virulent flu in humans were detected in Mexico and the southwestern United States, causing more than 60 deaths, mostly in Mexico City and central Mexico.[2] Some of these have been confirmed by the World Health Organization to be a never-before-seen strain of H1N1.[8][1] The story of the outbreak was broadcast live first in Mexico on April 23, 2009. A new swine flu strain has been confirmed in 16 of the deaths and at least 100 others are being tested as of April 24, 2009.[9] The Mexican fatalities are mainly young adults, a hallmark of pandemic flu.[10]

Mexican Health Minister José Ángel Córdoba on April 24, said "We’re dealing with a new flu virus that constitutes a respiratory epidemic that so far is controllable."[2]

United States

The first two cases detected in the US were two children living in San Diego County and Imperial County, who became ill on March 28 and 30.[11] A CDC alert concerning these two isolated cases was reported in the media on April 21.[12] As of April 24 eight human cases were known, including six in Southern California and two in Cibolo, Texas (both at Byron P. Steele II High School).[13] All eight patients have recovered.[14] A third possible case in a child who attends the same high school as the 2 other cases in Texas has been identified and the school is closed temporarily;[15] the boy and his family have since been quarantined. The acting director of the US Centers for Disease Control (CDC) said that preliminary tests on seven out of fourteen samples from patients in Mexico had matched the virus found in the US, which experts say is a new strain of swine flu.[9] None of the US patients had any contact with pigs, leading CDC officials to believe that human-to-human transmission has been occurring.[13]

On April 24, New York City health department dispatched a team of investigators to the private St. Francis Preparatory School in Queens after 150 students complained of symptoms consistent with the disease.[16] Several of the students had recently traveled to Mexico City.[17] According to some sources, Manuel Camacho Solís, former mayor of Mexico City and former foreign secretary, may have been infected by the virus.[18]

It was reported on April 25 that two new cases of swine flu had been confirmed in Dickinson County, Kansas; one patient had recently traveled to and from Mexico by plane, and the other was his wife.[19] Eight of the New York school cases were said to be "probable" swine flu by New York City Health Commissioner Dr. Thomas Frieden. [20]

Genetics and effects

Anne Schuchat, director of CDC's National Center for Immunization and Respiratory Diseases, said that the American cases were found to be made up of genetic elements from four different flu viruses—North American swine influenza, North American avian influenza, human influenza A virus subtype H1N1, and swine influenza virus typically found in Asia and Europe, "an unusually mongrelised mix of genetic sequences."[21] For two cases a complete genome sequence had been obtained. This complete genome is presently being worked with by U.S. scientists to prepare it for transition to become a vaccine. She said that the virus was resistant to amantadine and rimantadine, but susceptible to oseltamivir (Tamiflu) and zanamivir (Relenza).[22][23][24][25] Preliminary genetic characterization found that the hemagglutinin (HA) gene was similar to that of swine flu viruses present in U.S. pigs since 1999, but the neuraminidase (NA) and matrix protein (M) genes resembled versions present in European swine flu isolates. Viruses with this genetic makeup had not previously been found to be circulating in humans or pigs, but there is no formal national surveillance system to determine what viruses are circulating in pigs in the U.S.[26] The seasonal influenza strain H1N1 vaccine is thought to be unlikely to provide protection.[27]

In an interview on April 24, acting CDC director Dr. Richard Bessar said that it was still not understood why the American cases were primarily mild disease while the Mexican cases had led to multiple deaths. Differences in the viruses or co-infection were being considered. Only fourteen samples from Mexico had been tested by the CDC, with seven found to match the American strain, and the CDC was still in discussions with Mexico about plans to send an American investigative team. He said that the virus had likely passed through several cycles of infection with no known linkages between patients in Texas and California, and that containment of the virus is "not very likely".[28][29]

Pandemic concern

The U.S. Centers for Disease Control and the World Health Organization are concerned that this outbreak may become a pandemic, because:[30]

  • The virus is a new strain of influenza, from which human populations have not been vaccinated or naturally immunized.[31]
  • The virus has produced severe disease in Mexico, and some deaths. Furthermore, the illness has primarily struck young, healthy adults, much like the deadly Spanish Flu of 1918, unlike most influenza strains which produce the worst symptoms in young children, elderly adults, and others with weaker immune systems.[32][1]
  • The virus appears to infect by human-to-human transmission, and has spread to multiple regions within Mexico and multiple areas in the United States. Investigations of infected patients indicate no direct contact with swine, such as at a farm or agricultural fair.[1] In contrast, for example, disease transmission in the last severe human outbreak of influenza, the bird flu that peaked in 2006, was determined to be entirely or almost entirely from direct contact between humans and birds.[33]

Response

Canada

Dr. Michael Gardam, director of infectious disease prevention and control at Ontario's public health agency, said in an interview with the Canadian Broadcasting Corporation that an outbreak of swine flu in Ontario, Canada's most populous province, would not be as serious as the 2003 SARS epidemic.[34] In preparing for and dealing with influenza pandemic, the Public Health Agency of Canada follows the WHO's categories, but has expanded them somewhat.[35]

Denmark

Kåre Mølbak, department manager at Statens Serum Institut under the Danish Ministry of Health and Prevention, said the agency monitors developments in Mexico and are already able to identify the virus if any Danes should have been unfortunate enough to have become infected on a trip to Mexico. Hospitals have also been notified and instructed in what signs to look for.[36]

Ireland

Head of Health Protection with the HSE Dr Kevin Kelleher said: “The ECDC and the World Health Organisation has confirmed that no cases of this illness have occurred in Europe, but that we should continue to closely follow the emerging situation.”[37]

Mexico

Mexican soldiers distributing protective masks to citizens.

On April 24, 2009, schools (from pre-school to university level) as well as libraries, museums, concerts, and any public gathering place, were shut down by the government in Mexico City and the neighbouring State of Mexico to prevent the disease from spreading further. Marcelo Ebrard, Mexico City's mayor, has also asked all night-life operators to shut down their places for ten days to prevent further infections.[38] José Ángel Córdoba, federal Secretary of Health, said on April 24 that schools will probably be suspended for at least the following week, and that it will take around ten days to see the evolution of the virus' behavior, and to consider other measures after such.[39] On April 25, President Felipe Calderón declared an emergency which granted him the power to suspend public events and order quarantines.[40]

Peru

In response to the outbreak, Alex Kouri, governor of Peru, announced that the Callao Regional Government took precautionary steps to prevent entry of the virus by declaring a state of maximum air and sea alert.[41]

United Kingdom

The Health Protection Agency said on 4/24/09: "No cases of swine flu have been identified in the UK or anywhere in Europe. The reported events in the US and Mexico are unusual and warrant further investigation and vigilance on the part of other countries. More investigation and testing is needed to determine the severity of the disease and the ease with which it can spread."[42] On 4/25/09, a British Airways steward returning from Mexico fell ill in-flight with flu-like symptoms, and was quarantined upon landing, at Heathrow Airport.[43]

United Nations

The United Nations agency saw no need at this point to issue travel advisories warning travellers not to go to parts of Mexico or the United States. The spokesperson said that the situation might change "depending on what the situation in the field is".[44] WHO Director-General Margaret Chan also said that it was too premature to issue such recommendations without better analysis and understanding of the situation at this stage.[45]

United States

An official for the White House said, "The White House is taking the situation seriously and monitoring for any new developments. The president has been fully briefed." [46] Gov. Arnold Schwarzenegger and the state of California activated the Joint Emergency Operations Center of the Department of Public Health, and are coordinating with the California Emergency Management Agency, the CDC, and the Mexican government. They have additionally stepped up other preparations to lessen the flu's threat.[47]

World Health Organization

The World Health Organization (WHO) said in a statement "Because there are human cases associated with an animal influenza virus, and because of the geographical spread of multiple community outbreaks, plus the somewhat unusual age groups affected, these events are of high concern" and "WHO acknowledges the United States and Mexico for their proactive reporting and their collaboration with WHO and will continue to work with Member States to further characterize the outbreak".[1]

The WHO will convene a meeting of its Emergency Committee on international health regulations for emergency discussions. WHO Director-General Margaret Chan said that the emergency committee could make recommendations including whether to change the pandemic alert level or not.[44][48] The WHO stated that the viruses obtained from the human cases with swine influenza in the United States were sensitive to oseltamivir (Tamiflu)[49] and zanamivir (Relenza) but resistant to amantadine and remantadine. [50]

See also

References

  1. ^ a b c d e "Influenza-Like Illness in the United States and Mexico". World Health Organization. 2009-04-24. Retrieved 2009-04-25.
  2. ^ a b c Lacey, Marc (April 24, 2009). "Fighting Deadly Flu, Mexico Shuts Schools". The New York Times. {{cite news}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  3. ^ Reuters. Fatal new flu strain threatens Mexico, U.S. (April 25, 2009).
  4. ^ a b c Dobnik, Verena (2009-04-25). "2 swine flus in Kan., US total 11; 8 likely in NY". Associated Press. Retrieved 2009-04-25.
  5. ^ "Up to 200 possibly infected with swine flu at Queens high school". Thaindian News. 2009-04-26. Retrieved 2009-04-25.
  6. ^ "Cabin crew member in hospital after flight from swine flu-struck Mexico". The Guardian . 2009-04-25. Retrieved 2009-04-25.
  7. ^ "CDC Press Briefing Transcripts April 24, 2009". Cdc.gov. 2009-01-23. Retrieved 2009-04-25.
  8. ^ "Q&A: Swine flu". BBC News.
  9. ^ a b Experts probe deadly Mexico flu Published 24 April 2009
  10. ^ "Deadly new flu virus in US and Mexico may go pandemic", New Scientist, April 24, 2009
  11. ^ David Brown (April 22, 2009). "New Strain of Swine Flu Investigated: Two Children in San Diego Area Had No Contact with Pigs". Washington Post. Retrieved April 24, 2009.
  12. ^ Mike Stobbe (April 21, 2009). "Officials alert doctors after 2 California children infected with unusual swine flu". Associated Press. Retrieved April 24, 2009.
  13. ^ a b Stein, Rob (April 24, 2009). "In California and Texas, 5 New Swine Flu Cases". Washington Post. {{cite news}}: Cite has empty unknown parameter: |coauthors= (help)
  14. ^ "Experts probe deadly Mexico flu". BBC. 2009-04-24. Retrieved 2009-04-25.
  15. ^ Texas Department of State Health Services (2009-04-25). "School to Close, Other Flu Precautions Recommended" (PDF). Schertz-Cibolo-Universal City Independent School District. Retrieved 2009-04-25.
  16. ^ "150 kids sick at St. Francis Preparatory School in Queens". Nydailynews.com. Retrieved 2009-04-25.. Note: The Daily News article is misleading about the infections at other schools. See this April 17 WCBS-TV article, which reports the illness at one of the schools was norovirus, not influenza, and this April 21 Newsday article, which reports the illness at the other school was identified as a common form, not a new form, of influenza.
  17. ^ http://www.nytimes.com/2009/04/25/nyregion/25sick.html?ref=americas
  18. ^ "Camacho Solís fue víctima de la influenza". El Sol de Córdoba. 2009-04-25.
  19. ^ "Two swine flu cases confirmed in Dickinson County". The Wichita Eagle. 2009-04-25. Retrieved 2009-04-25. {{cite web}}: Italic or bold markup not allowed in: |publisher= (help)
  20. ^ [1]
  21. ^ http://www.newscientist.com/article/dn17025-deadly-new-flu-virus-in-us-and-mexico-may-go-pandemic.html
  22. ^ Steven Reinberg (2009-04-24). "Swine Flu Cases Now Total 7: CDC". ABC News.
  23. ^ Rob Stein (2009-04-23). "In California and Texas, 5 New Swine Flu Cases". Washington Post.
  24. ^ "CDC Briefing on Public Health Investigation of Human Cases of Swine Influenza". CDC online newsroom. 2009-04-23.
  25. ^ "Influenza-like illness in the United States and Mexico". WHO. 2009-04-24.
  26. ^ "Swine Influenza A (H1N1) Infection in Two Children --- Southern California, March--April 2009". CDC MMWR. 2009-04-22.
  27. ^ "Update: Swine Influenza A (H1N1) Infections --- California and Texas, April 2009". CDC MMWR. 2009-04-24.
  28. ^ "CDC Briefing on Public Health Investigation Reuters of Human Cases of Swine Influenza (transcript)". CDC. 2009-04-24.
  29. ^ "CDC says too late to contain U.S. flu outbreak". Reuters. 2009-04-24.
  30. ^ Besser, Richard, Acting Director CDC. CDC Press Transcript April 24, 2009 (unedited): "there are really three things we want to look for when we’re thinking about whether a virus is causing a new pandemic...".
  31. ^ U.S. Centers for Disease Control. Morbidity and Mortality Weekly Report Dispatch, April 21, 2009.
  32. ^ Stein, Rob and Brown, David. Washington Post (April 25, 2009). Swine Flu Found in Mexican Outbreak
  33. ^ Global spread of H5N1
  34. ^ "Swine flu not as serious as SARS: Canada's Ontario".
  35. ^ Public Health Agency of Canada: The Canadian Pandemic Influenza Plan for the Health Sector
  36. ^ http://www.dr.dk/Nyheder/Udland/2009/04/25/161845.htm
  37. ^ Irish Times: Irish authorities issue swine flu warning
  38. ^ [Pide Ebrard parar 10 días vida nocturna "Estima SSA 10 dias de alerta por influenza"]. Reforma. 2009-04-25. {{cite web}}: Check |url= value (help)
  39. ^ "Estima SSA 10 dias de alerta por influenza". El Universal. 2009-04-25.
  40. ^ "Mexico's Calderon Declares Emergency Amid Swine Flu Outbreak". Bloomberg. 2009-04-25.
  41. ^ "Peru: Callao on maximum alert over swine flu". Living In Peru. 2009-04-25. Retrieved 2009-04-25. {{cite web}}: |first= missing |last= (help)
  42. ^ http://www.google.com/hostednews/ukpress/article/ALeqM5ivLHkdy6zHsVDh107eDG-v8mu6Gg The Press Association: UK authorities monitor deadly flu]
  43. ^ "Cabin crew member in hospital after flight from swine flu-struck Mexico". The Guardian . 2009-04-25. Retrieved 2009-04-25.
  44. ^ a b "WHO ready with antivirals to combat swine flu". Reuters. 2009-04-24.
  45. ^ "Virtual press briefing - swine influenza (25 April 2009)". WHO.
  46. ^ "White House closely following U.S. swine flu outbreak".
  47. ^ "Gov. Schwarzenegger Directs State Swine Flu Response". 2009-04-24. Retrieved 2009-04-25.
  48. ^ "WHO calls emergency meeting on swine flu".
  49. ^ "WHO Says Initial Findings Show Swine Flu Responds To Tamiflu". Nasdaq.com. Retrieved 2009-04-25.
  50. ^ "Swine influenza questions and answers" (PDF). WHO.