2009 Nu Flu
On 05 May 2009 HHS Secretary Kathleen Sebelius and Acting CDC Director Dr. Richard Besser stated that "We have learned that in many communities, the virus is widely circulating. When influenza becomes common in a community, it is unlikely that actions such as closing schools or daycare facilities are effective when it comes to slowing or stopping the spread of influenza viruses. Instead, such measures bring significant cost-such as interrupting student learning-without a significant public health benefit. In addition, we have learned that the disease currently being caused by this novel flu virus appears to be similar with that typically caused by seasonal influenza. Although many people may get sick, the available data do not indicate we are facing an unusually severe influenza virus.... CDC no longer recommends that communities with a laboratory-confirmed case of influenza A H1N1 consider adopting school dismissal or childcare closure measures..."
Although the influenza (flu) season is just ending in the northern hemisphere, it is now beginning in the southern hemisphere. South America has confirmed its first case of the virus in Columbia. In the northern hemisphere, flu season runs from October to March, while in the southern hemisphere, the season covers the remaining months, April to September. The number of confirmed swine flu cases in the United States climbed Monday 04 May 2009 to 286 in 36 states. But the revised numbers indicate catching up on a backlog of lab tests, and not a sudden rise in new infections. The US Education Department has said that more than 430 schools had closed, affecting about 245,000 children. "We are seeing encouraging signs that the virus so far is not looking more severe than a strain we would see during seasonal flu," concluded Center for Disease Control (CDC) Acting Director Dr. Richard Besser. Mexico declared the epidemic to be waning. They scaled back their flu alert, saying they would allow cafes, museums and libraries to reopen this week after a five-day shutdown of nonessential businesses. Inspections of schools must be finished before students can return to class.
In influenza outbreak of April 2009 has several official names (A/H1N1 influenza like human illness, Novel H1N1 Flu (Formerly Swine Flu), swine-origin influenza A H1N1), with an acronym (S-OIV), several nicknames (swine flu) and an apparent birthplace (Mexico). Some suggest this flu should be named "Mexican" influenza in deference to Muslim and Jewish sensitivities over pork.
The "case-fatality rate", the fraction of infected people who die, was 2 to 2.5 percent for the United States as a whole in the 1918 Spanish Flu, while the Asian influenza of 1957-58 had a fatality rate of 0.2-0.5, and the Hong Kong flu of 1968-69 was 0.1 percent, about that of seasonal flu. As of 0600 GMT, 3 May 2009, 17 countries have officially reported 787 cases of influenza A(H1N1) infection. Mexico had reported 506 confirmed human cases of infection, including 19 deaths, a case-fatality rate of 3.7%.
The "case reproduction number" or "basic reproductive number" [RO] - how many people are infected by each new case - determines the potential for the spread of a disease. The case reproductive number for measles, which is highly contagious, is above 15; smallpox is over 5. With seasonal influenza, the reproductive number ranges from 1.5 to 3.0. On 02 May 2009 The Washington Post reported that Miguel Ángel Lezana, the director of Mexico's National Center for Epidemiology and Disease Control, said that "According to the preliminary models, the reproductive number that we have in the Mexico City metropolitan area is 1.5." With a novel flu virus the R0 will typically start out low, probably a little above 1.0, and then with each generation of transmission it will increase as the virus adapts to the human population. One study estimated that the reproduction number of the 1918 Spanish Flu was initially about 1.5, and then about 3.5 in the second wave.
The U.S. health authorities reported Sunday 03 May 2009 "encouraging signs" in the swine flu epidemic, believing that this virus is no more dangerous than seasonal flu. "We see encouraging signs," said the director of the Centers federal control and disease prevention (CDC), Richard Besser, interviewed on Fox TV. "We must put things in perspective. Seasonal flu strikes us that each year kills 36,000 people in the United States, he said. In the case of swine influenza A/H1N1, "it is encouraging that this virus does not seem far more severe than seasonal flu strain." Days after Mexico suspended public activities to reduce the spread of swine flu, the country is reporting a leveling off in the rate of new infections. In the United States, the number of confirmed influenza cases continues to rise, but most flu sufferers report relatively mild symptoms, and only one death has been recorded.
As of 0600 GMT, 3 May 2009, 17 countries have officially reported 787 cases of influenza A(H1N1) infection. Mexico had reported 506 confirmed human cases of infection, including 19 deaths. The higher number of cases from Mexico in the past 48 hours reflected ongoing testing of previously collected specimens. Mexican authorities have scaled back their estimate of how many people could have died from the flu strain to over 100, down from 176. The United States Government reported 160 laboratory confirmed human cases, including one death. The US Centers for Disease Control and Prevention said the new flu had spread to 30 US states and infected 226 people. The following countries reported laboratory confirmed cases with no deaths - Austria (1), Canada (70), China, Hong Kong Special Administrative Region (1), Costa Rica (1), Denmark (1), France (2), Germany (6), Ireland (1), Israel (3), Netherlands (1), New Zealand (4), Republic of Korea (1), Spain (13), Switzerland (1) and the United Kingdom (15).
US President Barack Obama says his administration has taken aggressive action to confront the outbreak of the H1N1 swine flu virus and prepare for the possibility that it could get worse. In a weekly address Saturday, Mr. Obama said he has asked Congress for $1.5 billion to develop a vaccine and buy treatments that are already available and effective against the current strain.
The situation continues to evolve. As of 06:00 GMT, 2 May 2009, 15 countries had officially reported 615 cases of influenza A(H1N1) infection. Mexico reported 397 confirmed human cases of infection, including 16 deaths. The 241 rise in cases from Mexico compared to 23:30GMT of 1 May reflect ongoing testing of previously collected specimens. Initially, Mexico had reported as many as 2,500 suspected cases. The mysteriously high mortality in Mexico had been thought to possibly be a result of Mexico having hundreds of thousands, and possibly millions, of cases, with all but the most serious hidden in background of illness in a crowded population.
The United States Government reported 141 laboratory confirmed human cases, including one death. Mexican health officials say fewer than half of the suspected cases there turned out to test positive for swine flu. U.S. health officials says tests indicate the virus is not as strong as the 1918 strain, which killed tens of millions of people worldwide.
As of 06:00 GMT, 1 May 2009, 11 countries had officially reported 331 cases of influenza A(H1N1) infection. The United States Government reported 109 laboratory confirmed human cases, including one death. Mexico reported 156 confirmed human cases of infection, including nine deaths. The following countries reported laboratory confirmed cases with no deaths - Austria (1), Canada (34), Germany (3), Israel (2), Netherlands (1), New Zealand (3), Spain (13), Switzerland (1) and the United Kingdom (8).
The World Health Organization states that "There is also no risk of infection from this virus from consumption of well-cooked pork and pork products." In Egypt, the government began slaughtering the country's 350,000 to 400,000 pigs, despite objections from global health experts who said that the slaughter was unnecessary. "The crisis today is in transmission from human to human. It has nothing to do with pigs," said Joseph Domenech, UN Food and Agriculture Organization chief veterinary officer. One Islamic militant Web site stated that the swine flu was "God's revenge against the infidels."
Mexican President Felipe Calderon urged people to stay at home while the federal government suspends non-essential activities in an effort to combat the spread of swine flu. Other countries with confirmed cases are Austria, Britain, Canada, Costa Rica, Germany, Israel, Spain, New Zealand and Switzerland. Australia, Colombia, France, Denmark and South Korea are among nations investigating suspected cases. By 30 April 2009 the number of swine flu cases in New York City had grown to hundreds of confirmed or suspected cases, mostly among students. The U.S. Centers for Disease Control and Prevention said at least 91 people in 10 U.S. states had been infected. Some schools were closed in the United States. The city of Fort Worth, Texas says all 144 of its schools will be closed indefinitely beginning Thursday, after a case of swine flu was confirmed at one school.
On 29 April 2009 the World Health Organization decided to raise the current level of influenza pandemic alert from phase 4 to phase 5, based on assessment of all available information, and following several expert consultations. WHO Director-General, Dr Margaret Chan, said "Influenza pandemics must be taken seriously precisely because of their capacity to spread rapidly to every country in the world. ... New diseases are, by definition, poorly understood. Influenza viruses are notorious for their rapid mutation and unpredictable behaviour. ... All countries should immediately activate their pandemic preparedness plans. Countries should remain on high alert for unusual outbreaks of influenza-like illness and severe pneumonia. ... From past experience, we ... know that influenza may cause mild disease in affluent countries, but more severe disease, with higher mortality, in developing countries."
Phase 5 is characterized by human-to-human spread of the virus into at least two countries in one WHO region. While most countries will not be affected at this stage, the declaration of Phase 5 is a strong signal that a pandemic is imminent and that the time to finalize the organization, communication, and implementation of the planned mitigation measures is short. Phase 6, the pandemic phase, is characterized by community level outbreaks in at least one other country in a different WHO region in addition to the criteria defined in Phase 5. Designation of this phase will indicate that a global pandemic is under way.
By 29 April 2009 the situation continued to evolve rapidly. As of 18:00 GMT, 29 April 2009, nine countries had officially reported 148 cases of swine influenza A/H1N1 infection. The United States Government had reported 91 laboratory confirmed human cases, with one death.Mexico remains the epicenter of the swine flu outbreak, with more than 150 deaths blamed on the virus. Mexico has reported 26 confirmed human cases of infection including seven deaths. The following countries have reported laboratory confirmed cases with no deaths - Austria (1), Canada (13), Germany (3), Israel (2), New Zealand (3), Spain (4) and the United Kingdom (5).
By 28 April 2009 as many as 152 people had died in Mexico with suspected swine flu, and the number of worldwide cases confirmed by laboratory tests reached 79. The number of confirmed cases of swine flu in the US reached 64, with most in New York City. Five states had outbreaks, including New York with 45, California with 10, Texas 6, Kansas 2, and Ohio 1. The U.K., Israel, Canada, New Zealand and Spain have also confirmed outbreaks.
The World Health Organization Director-General raised the level of influenza pandemic alert on 27 April 2007 from the current phase 3 to phase 4. The change to a higher phase of pandemic alert indicates that the likelihood of a pandemic has increased, but not that a pandemic is inevitable. Given the widespread presence of the virus, the Director-General considered that containment of the outbreak is not feasible. The current focus should be on mitigation measures. The Director-General recommended not to close borders and not to restrict international travel.
Phase 4 is characterized by verified human-to-human transmission of an animal or human-animal influenza reassortant virus able to cause "community-level outbreaks." The ability to cause sustained disease outbreaks in a community marks a significant upwards shift in the risk for a pandemic. Any country that suspects or has verified such an event should urgently consult with WHO so that the situation can be jointly assessed and a decision made by the affected country if implementation of a rapid pandemic containment operation is warranted. Phase 4 indicates a significant increase in risk of a pandemic but does not necessarily mean that a pandemic is a forgone conclusion. The current pandemic phases were first introduced in 2005 and WHO had never been at any phase higher than Phase 3 under the current system of pandemic phases.
The Obama administration declared a "public health emergency" on 26 April 1009, which Homeland Security Secretary Janet Napolitano called a "standard operating procedure". Obama administration officials hosted an on-camera briefing this afternoon in the White House Press Briefing Room to provide an update on swine influenza in the United States and the government response by Secretary Janet Napolitano, Department of Homeland Security; Dr. Richard Besser, Acting Director, Centers for Disease Control and Prevention; John Brennan, Assistant to the President for Homeland Security; and White House Press Secretary Robert Gibbs. The government said it will release 25 percent of its stockpiles of the flu-fighting drugs Tamiflu and Relenza.
The virus that has caused these infections is viruses are actually very interesting. They contain genetic segments from four different virus sources. Some gene segments are North American swine influenza viruses. Some gene segments North American avian influenza viruses. One gene segment from a human influenza virus and two gene segments that are normally found from swine influenza viruses in Asia and in Europe.
Mexican and US officials are taking emergency steps to contain the possible outbreak of a new multi-strain H1N1 swine flu that has killed at least 20 people and may be responsible for scores of other deaths, with over 1,000 more hospitalized. This seems to have gone on in Mexico at least a month before the US knew about it. Mexican health officials confirmed at least 20 deaths and possibly more than 80 associated with the new flu strain and ordered the most sweeping shutdown of public gathering places in decades. Mexico's health minister, Jose Angel Cordoba, says the new influenza mutated from pigs to humans and is now considered a "respiratory outbreak." This is why the Health Ministry in Mexico City recommended that people avoid crowded places.
Symptoms resemble the regular human seasonal influenza and include fever, lethargy, lack of appetite and coughing, though some people with swine flu experience a runny nose, sore throat, nausea, vomiting and diarrhea. The presenting symptoms may look just exactly like regular flu. There may be a little bit more diarrhea or vomiting then in regular flu. The syndrome in Mexico is nonspecific or general, severe pneumonia. There is a lot of severe pneumonia that happens all the time, separate from the new influenza. The World Health Organization [WHO] reported hundreds of cases of flu-like symptoms in Mexico in recent weeks, most of them among healthy young adults, with 57 deaths in Mexico City. Most patients were previously healthy young adults between the ages of 25 and 44. Symptoms included fever, headache, ocular pain, shortness of breath, and fatigue that rapidly progressed to severe respiratory distress in about 5 days.
On April 17, 2009, CDC and the California Department of Public Health determined that two cases of febrile respiratory illness occurring in children who reside in adjacent counties in southern California were caused by infection with a swine influenza A (H1N1) virus. On April 22, CDC confirmed an additional three cases of swine influenza among residents of the two counties, two adults and one adolescent.
The Government of Mexico reported three separate events. In the Federal District of Mexico, surveillance began picking up cases of Influenza-Like Illness (ILI) starting 18 March 2009. The number of cases rose steadily through April and as of 23 April there were more than 854 cases of pneumonia from the capital. Of those, 59 had died. In San Luis Potosi, in central Mexico, 24 cases of ILI, with three deaths, had been reported. And from Mexicali, near the border with the United States, four cases of ILI, with no deaths, have been reported. The majority of these cases have occurred in otherwise healthy young adults. Influenza normally affects the very young and the very old, but these age groups had not been heavily affected in Mexico.
During the 1918-1919 pandemic, overall mortality and case-fatality rates were higher for young adults. Research had suggested that the immune system's overreaction to certain flu strains may be the key to their lethal effects. The virus was so lethal because the immune system overreacted to the virus, causing a complex "cytokine storm" in the body. Cytokines are immune molecules that help coordinate immune cells to fight off infection. In small doses they are protective, but at larger doses, they can be very destructive, creating uncontrolled inflammation leading to severe lung damage. A severe "cytokine storm" can flood and clog the lung's alveoli with infection-fighting cells, making it so oxygen can no longer be properly absorbed.
The Swine Influenza A/H1N1 viruses characterized in this outbreak had not been previously detected in pigs or humans. The viruses so far characterized had been sensitive to oseltamivir, but resistant to both amantadine and rimantadine.During week 15 (April 12-18, 2009), seasonal influenza activity continued to decrease in the United States. Nine states reported regional activity; 17 states reported local influenza activity; the District of Columbia and 22 states reported sporadic influenza activity; and two states reported no influenza activity. Seven human infections with swine influenza A (H1N1) virus had been confirmed. On April 17, 2009, CDC and the California Department of Public Health determined that two cases of febrile respiratory illness occurring in children who reside in adjacent counties in southern California were caused by infection with a swine influenza A (H1N1) virus. On April 22, CDC confirmed an additional three cases of swine influenza among residents of the two counties, two adults and one adolescent.
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