AUSTRALIA is facing its worst influenza season in years, as specialists warn that even young, fit adults could be affected.
This year, 3084 cases of influenza have been reported to health authorities -- compared with 1213 cases for the entire 2006. Queensland has been hardest hit, with 1414 cases this year, compared with 518 in NSW, 498 in Western Australia and 220 in Victoria.
Ian Barr, deputy director of the World Health Organisation Collaborating Centre for Reference and Research on Influenza in Melbourne, said this year's flu season was the most serious since 2003 and 1997.
Six people -- five children and a 37-year-old man -- have died of influenza this year. A report in The Daily Telegraph today reveals that influenza played a role in the death of 30-year-old heart transplant recipient Joseph David, from Sydney.
"It's certainly bigger this year than it has been in the last couple of years," Dr Barr said. "The last serious flu season was in 2003. We had very mild seasons in 2004, 2005 and 2006."
Experts are at a loss to explain why the outbreak is spreading so rapidly. "We've definitely seen a higher rate of cases in Sydney, Canberra, Brisbane and Perth than in the past few years," said Canberra Hospital director of infectious diseases and microbiology Peter Collignon. "But it's not clear why. It's puzzling because there hasn't been a great change in the virus."
Dr Barr said people's immunity might have fallen in recent years. "We often see a serious season following after a few mild seasons in a row," he said. "That may be due to a lack of circulation of strains, and a lack of exposure to people with influenza for a few years. Their immunity wanes and then they come down with it. People think it only affects the young, sick and elderly, but ... everyone is susceptible."
Three children in Western Australia, one in Queensland and one in Victoria have died from influenza in the past five weeks.
On Thursday, Queenslander Glen Kindness -- a healthy 37-year-old -- died after developing flu-like symptoms.
"About 20 per cent of the population gets vaccinated," Dr Barr said. "I think we'd all like to see that rate higher."
Experts have long warned there is no way to vaccinate people against a new strain of influenza until that strain evolves. However, yesterday, researchers revealed they might have come up with a way to vaccinate people before an influenza pandemic.
The World Health Organisation has confirmed that 319 people have contracted H5N1 avian flu virus from contact with infected chickens, ducks and other fowl, and 192 of them have died. Researchers at the National Institute of Allergy and Infectious Diseases in Maryland claim they have discovered a way to anticipate how H5N1 may jump to humans and ways to respond to it.
They found a mutation that causes one strain of the H1N1 virus to infect birds, while another strain prefers humans. The team made the same alteration in an H5N1 virus, and vaccinated mice with this genetically engineered H5N1 DNA. They found an antibody that could neutralise both types of H5N1.
"It delivers a powerful blow against this virus and really hits it where it lives," said institute director and lead author Gary Nabel. If a vaccine could be developed to protect people against viruses with this mutation, it could be used before a pandemic even started, Dr Nabel said.
Showing posts with label Influenza. Show all posts
Showing posts with label Influenza. Show all posts
Tuesday, November 6, 2007
Flu Season - Influenza
Influenza-like illness (ILI) is defined as a temperature of > 100.0?F (> 37.8?C) and either cough or sore throat in the absence of a known cause. Levels of influenza activity are 1) no activity, 2) sporadic-small numbers of laboratory-confirmed influenza cases or a single influenza outbreak reported but no increase in cases of ILI, 3) local-outbreaks of influenza or increases in ILI cases and recent laboratory-confirmed influenza in a single region of a state, 4) regional-outbreaks of influenza or increases in ILI cases and recent laboratory-confirmed influenza in at least two but less than half the regions of a state, and 5) widespread-outbreaks of influenza or increases in ILI cases and recent laboratory-confirmed influenza in at least half the regions of a state.
Influenza incidence exhibits strong seasonal fluctuations in temperate regions throughout the world, concentrating the mortality and morbidity burden of the disease into a few months each year. Influenza is more likely to spread in the winter than the summer. This may be caused by an increased infectiousness of the disease, an increased susceptibility of people, or an increased number contacts with others that might result in transmitting the infection during the winter. For example, people may spend more time indoors.
The reason that more people catch the flu in the winter appears to be that small seasonal changes in flu transmission at the individual level are greatly amplified as the disease spreads through communities. The underlying cause of seasonal fluctuations in transmission may be too small to measure. Large fluctuations in the number of flu cases between winter and other seasons may be caused by very small changes in the number of people infected by a single infectious person. These small changes in transmission rate are amplified by interactions between the evolving virus and the changing level of immunity that people have to specific strains.
The cause of influenza's seasonality has remained elusive. Studies have failed to establish whether these transmission changes are due to direct effects of temperature and humidity on transmission, to changes in mixing patterns [e.g., school terms or simply more time spent indoors], or to other factors, such as increased viral production under winter conditions. In fact, it may be impossible to establish the underlying cause of seasonality in influenza epidemics, since the large observed oscillations in incidence can be generated by seasonal changes in the transmission rate that are too small to measure. The large oscillations in incidence may be caused by undetectably small seasonal changes in the influenza transmission rate that are amplified by dynamical resonance.
Data can be evaluated quantitatively, and graphic representation of this information, known as epidemic curves (epi-curves), may prove especially useful in this endeavor. These visual representations depict case frequency over time, and are initially used to obtain tentative answers to questions concerning origin, propagation, incidence, prevalence, and likely modes of transmission. The nature of the epidemic curve varies with the pathogen. The frequency curve for most infectious diseases resembles a logarithmic normal curve. Epidemics such as infuenza have distinctive patterns of initiation and spread.
Influenza incidence exhibits strong seasonal fluctuations in temperate regions throughout the world, concentrating the mortality and morbidity burden of the disease into a few months each year. Influenza is more likely to spread in the winter than the summer. This may be caused by an increased infectiousness of the disease, an increased susceptibility of people, or an increased number contacts with others that might result in transmitting the infection during the winter. For example, people may spend more time indoors.
The reason that more people catch the flu in the winter appears to be that small seasonal changes in flu transmission at the individual level are greatly amplified as the disease spreads through communities. The underlying cause of seasonal fluctuations in transmission may be too small to measure. Large fluctuations in the number of flu cases between winter and other seasons may be caused by very small changes in the number of people infected by a single infectious person. These small changes in transmission rate are amplified by interactions between the evolving virus and the changing level of immunity that people have to specific strains.
The cause of influenza's seasonality has remained elusive. Studies have failed to establish whether these transmission changes are due to direct effects of temperature and humidity on transmission, to changes in mixing patterns [e.g., school terms or simply more time spent indoors], or to other factors, such as increased viral production under winter conditions. In fact, it may be impossible to establish the underlying cause of seasonality in influenza epidemics, since the large observed oscillations in incidence can be generated by seasonal changes in the transmission rate that are too small to measure. The large oscillations in incidence may be caused by undetectably small seasonal changes in the influenza transmission rate that are amplified by dynamical resonance.
Data can be evaluated quantitatively, and graphic representation of this information, known as epidemic curves (epi-curves), may prove especially useful in this endeavor. These visual representations depict case frequency over time, and are initially used to obtain tentative answers to questions concerning origin, propagation, incidence, prevalence, and likely modes of transmission. The nature of the epidemic curve varies with the pathogen. The frequency curve for most infectious diseases resembles a logarithmic normal curve. Epidemics such as infuenza have distinctive patterns of initiation and spread.
Influenza Vaccination Season Begins
The Michigan Department of Community Health (MDCH) is gearing up for the 2007-2008 influenza season by making special efforts to reach out to high-risk patients as well as children in need of a second dose of influenza vaccine. Vaccine manufacturers expect shipments to be made on-time this year and MDCH is urging providers, local health departments, and community vaccinators to begin vaccinating patients.
"As the 2007-2008 flu season approaches, we encourage all of Michigan's residents to be vaccinated against the flu," said Janet Olszewski, MDCH Director. "Ask your doctor if you are at high-risk for influenza-related complications and be sure to get vaccinated. If you are a new parent, a health care professional, and/or have contact with people age 65 and older, protect those high-risk individuals by getting vaccinated."
According to the U.S. Centers for Disease Control and Prevention (CDC), every year in the United States, an average of 5 percent to 20 percent of the population gets the flu, more than 200,000 people are hospitalized from flu complications, and about 36,000 people die from flu. More than 90 percent of those deaths are among persons age 65 or older. Even though last year's flu season was mild, 68 deaths among children were reported to CDC.
"The single best way to prevent the flu is to get vaccinated each year," said Dr. Greg Holzman, State Chief Medical Executive. "Contrary to popular myth, the flu vaccine cannot give you the flu. There are two types of flu vaccinations available: the "flu shot" and the nasal-spray flu vaccine; both are effective in preventing the flu."
Studies show people with flu can infect others up to 1 day before they start having symptoms and, once sick, they can infect others for up to 5 days. About half of all people with influenza infections do not have any symptoms; these people can infect others without knowing they are sick.
Influenza activity most often occurs in January or later, therefore it is important to know that if you do not get vaccinated in October or November, you can still get get vaccinated in December or later. Though it varies, flu season can last until May. For information on receiving the flu vaccine, please contact your doctor's office or your local health department.
"As the 2007-2008 flu season approaches, we encourage all of Michigan's residents to be vaccinated against the flu," said Janet Olszewski, MDCH Director. "Ask your doctor if you are at high-risk for influenza-related complications and be sure to get vaccinated. If you are a new parent, a health care professional, and/or have contact with people age 65 and older, protect those high-risk individuals by getting vaccinated."
According to the U.S. Centers for Disease Control and Prevention (CDC), every year in the United States, an average of 5 percent to 20 percent of the population gets the flu, more than 200,000 people are hospitalized from flu complications, and about 36,000 people die from flu. More than 90 percent of those deaths are among persons age 65 or older. Even though last year's flu season was mild, 68 deaths among children were reported to CDC.
"The single best way to prevent the flu is to get vaccinated each year," said Dr. Greg Holzman, State Chief Medical Executive. "Contrary to popular myth, the flu vaccine cannot give you the flu. There are two types of flu vaccinations available: the "flu shot" and the nasal-spray flu vaccine; both are effective in preventing the flu."
Studies show people with flu can infect others up to 1 day before they start having symptoms and, once sick, they can infect others for up to 5 days. About half of all people with influenza infections do not have any symptoms; these people can infect others without knowing they are sick.
Influenza activity most often occurs in January or later, therefore it is important to know that if you do not get vaccinated in October or November, you can still get get vaccinated in December or later. Though it varies, flu season can last until May. For information on receiving the flu vaccine, please contact your doctor's office or your local health department.
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