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Updated 22 minutes ago
When health officials develop a vaccine every influenza season (from October to May in the US), they choose virus strains to include, based on versions recently distributed around the world.
US Centers for Disease Control and Prevention and organizations such as this one can rely on a global influenza surveillance system involving more than 100 Member States – a tool that has not been available. not available in 1918, when an influenza pandemic made sick more than a third of the world's population. and killed at least 50 million people, or even 100 million.
About 5,000 people were reported dead in Pittsburgh, and another 2,000 in Westmoreland County.
The past century has brought increased knowledge of the influenza virus – isolated for the first time in the 1930s – as well as vaccines to provide immunity against many known strains. Progress has also been made in the preparation and response to influenza infections, including the development of antiviral drugs to treat the disease.
Modern researchers are still exploring other approaches to provide better protection against influenza strains.
"We have better hospitals that can care for people with the flu," said Dr. David Wyszomierski, a physician at Excela Latrobe Pediatrics, who attended a lecture series at Westmoreland County Community College last year. on influenza concerns. "We have faster diagnostic tools that allow us to know which strains are circulating. The CDC keeps track of what's going around. "
But predictions of seasonal influenza varieties are flawed because strains continue to evolve and sometimes exceed the species barrier between animals and humans.
Similarly, warns the CDC, it is impossible to predict when the next pandemic will occur.
Wyszomierski said health officials were monitoring what so-called bird flu viruses in recent years, which were passed from wild birds to domestic birds, and then to the birds. man, mainly in Asia. Migratory birds harbor and naturally spread various influenza viruses.
"They have infected only a few human beings and are not transmissible from person to person," Wyszomierski said. "If such a virus manages to be transmissible between humans, it could cause a global epidemic."
Although rare and infrequent, influenza epidemics are becoming pandemics that are spreading around the world, infecting and killing on a large scale. Researchers believe that influenza outbreaks date back to the Middle Ages, if not earlier.
In addition to the most deadly epidemic of 1918, other known influenza pandemics of all time hit in 1889, 1957, 1968, and 1977 – the last would have been caused by an untold influenza strain since the years 1950, escaped from a Chinese laboratory that was probably working on a vaccine. .
The most recent flu pandemic in the United States is a new H1N1 virus, which was detected in California in April 2009, a month after its first appearance in Mexico. The letters refer to the types of virus proteins that play a key role in creating effective vaccines.
The H1N1 strain hit the world in 1918 and spawned viral offspring in the decades that followed. The 2009 virus was "another genetic product in the family tree of this remarkable, still-growing 1918 virus," noted researchers in an article published by the New England Journal of Medicine.
The 2009 virus did not have as much impact as the 1918 virus, which claimed the lives of nearly 700,000 people in the United States. According to the CDC, the 2009 global outbreak caused 2,125 confirmed deaths in the United States, including 344 children.
Health officials quickly discovered antiviral drugs – which did not exist a century ago, when scientists were unaware of viruses or how to treat them – that could be used to treat the disease from 2009 until a vaccine is ready for distribution in October.
The researchers determined that the 2009 virus contained genetic material derived from human, avian and porcine viruses from various continents. This virus has now become one of the usual seasonal varieties to which a vaccine can be administered.
The 1918 flu may have mitigated the shock of the 2009 pandemic, according to Seema Lakdawala, an assistant professor of microbiology and molecular genetics, who heads a research laboratory on influenza at the University of Pittsburgh.
"The 2009 H1 protein is very similar to the 1918 H1," Lakdawala said. "People born before 1957, who had seen the same H1 virus, were protected from the 2009 pandemic," thus gaining immunity against the similar viral component.
Find answers
The extreme virulence of the 1918 flu has long confused officials, but researchers have found clues.
In 2005, Terrence Tumpey, a CDC microbiologist, was the first researcher to reconstruct and study the 1918 influenza virus, applying reverse genetics to lung tissue preserved from the victims of the pandemic.
His work revealed that two types of 1918 virus genes were "essential for maximum replication and virulence," Tumpey said in an interview published on the CDC website. "With this data in hand, some scientists have estimated that these virus genes could be a potential target for a new generation of anti-influenza A drugs."
Of the four basic types of influenza viruses, type A is most commonly associated with an inter-species infection and a pandemic.
Lakdawala has also been working on methods to prevent the spread of the influenza virus in humans.
"We are focusing on seasonal human viruses," she said. "We moult it and try to lose its ability to transmit in the air."
Formerly associated with the National Institutes of Health, Lakdawala operated his Pittsburgh laboratory for three years. But she has been studying the transmission of the flu since 2009.
"We have learned so much in the last 10 years," she said. "Previously, the CDC had only one laboratory that examined the transmission of the flu by air. Now, several laboratories around the world are studying it. "
Lakdawala emphasized the importance of ventilation to exchange air inside a building and to help disperse airborne flu viruses expelled by a person infected with the disease. It is equally important to wipe the affected surfaces such as doorknobs and elevator buttons, where viruses may be present, she said.
Research has revealed that influenza viruses can remain stable in the air for at least an hour and up to 16 hours when they are present in mucus on certain surfaces, according to a published article. by Lakdawala and his colleague Linsey Marr, a Virginia Tech professor.
According to Wyszomierski, medical centers in the United States and Britain are working to develop a more sustainable universal vaccine against seasonal influenza strains that can be effective for five years or more between doses.
Until this breakthrough occurs, he said, "It's always best to follow the CDC's instructions and be vaccinated against the flu every year."
Jeff Himler is an editor of Tribune-Review. You can contact Jeff at 724-836-6622, [email protected] or via Twitter @jhimler_news.
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