When was influenza virus discovered

Similar to the experiments involving mice, the virus quickly multiplied and spread within the human lung cells. So much so, that the virus produced as much as 50 times the amount of virus in human lung cells as one of the comparison viruses. Another set of experiments was conducted to better understand the possible avian origins of the virus. The earlier sequencing efforts led by Dr. Researchers were interested to know whether the virus would be lethal to fertilized chicken eggs, i.

To find an answer, day old fertilized chicken eggs were inoculated with the virus. The virus proved lethal for the chicken egg embryos, similar to the effects caused by contemporary H1N1 bird flu viruses. Furthermore, the recombinant flu viruses that Dr. Tumpey created containing two, five or seven genes of the virus also did not hurt chicken embryos.

The work conducted by Dr. Tumpey and his CDC colleagues provided new information about the properties that contributed to the virulence of the virus. Tumpey determined that the HA and PB1 virus genes of the virus played particularly important roles in its infectiousness and severity.

In that way, the virus was special — a uniquely deadly product of nature, evolution and the intermingling of people and animals.

Crowded conditions and the movement of troops during World War I likely contributed to the spread of the virus around the world. Photo credit: www. Since , the world has experienced three additional pandemics, in , , and most recently in These subsequent pandemics were less severe and caused considerably lower mortality rates than the pandemic. Many experts think so. One virus in particular has garnered international attention and concern: the avian influenza A H7N9 virus from China.

However, it has not gained the capability to spread quickly and efficiently between people. If it did, experts believe it could result in a pandemic with severity comparable to the pandemic. So far, it has shown only limited ability to spread between people.

Most human infections with this virus have result from exposure to birds. When considering the potential for a modern era high severity pandemic, it is important; however, to reflect on the considerable medical, scientific and societal advancements that have occurred since , while recognizing that there are a number of ways that global preparations for the next pandemic still warrant improvement.

Besides the properties of the virus itself, many additional factors contributed to the virulence of the pandemic. In , the world was still engaged in World War I.

Movement and mobilization of troops placed large numbers of people in close contact and living spaces were overcrowded. In addition, medical technology and countermeasures at the time were limited or non-existent. No diagnostic tests existed at the time that could test for influenza infection. Influenza vaccines did not exist at the time, and even antibiotics had not been developed yet. For example, penicillin was not discovered until Likewise, no flu antiviral drugs were available.

Critical care measures, such as intensive care support and mechanical ventilation also were not available in In terms of national, state and local pandemic planning, no coordinated pandemic plans existed in Some cities managed to implement community mitigation measures, such as closing schools, banning public gatherings, and issuing isolation or quarantine orders, but the federal government had no centralized role in helping to plan or initiate these interventions during the pandemic.

Today, considerable advancements have been made in the areas of health technology, disease surveillance, medical care, medicines and drugs, vaccines and pandemic planning. Flu vaccines are now produced and updated yearly, and yearly vaccination is recommended for everyone 6 months of age and older. Antiviral drugs now exist that treat flu illness, and in the event of virus exposure, can be used for prophylaxis prevention , as well.

Importantly, many different antibiotics are now available that can be used to treat secondary bacterial infections. Diagnostic tests for identifying influenza are now available and they are improving over time. Just as important as these advancements in diagnostic tests are the improvements that have been made in laboratory testing capacity both within the United States and globally.

Through animal and human interactions and environmental exposures, these viruses can cause human infections. The WHO collaborating centers collect influenza viruses obtained from respiratory specimens from patients around the world, and they are supported by National Influenza Centers in WHO member countries.

Expanding laboratory testing and flu surveillance capacity around the world has been an important focus of pandemic preparedness efforts. In , CDC began an international surveillance capacity building initiative that entailed a 5-year period of financial support to improve laboratory diagnostic tests and surveillance of influenza like illness ILI and severe acute respiratory infection SARI in 39 partner countries.

This considerably enhanced the ability of the global flu surveillance community to track spread of the virus. This requirement is designed to help quickly identify emerging viruses with pandemic potential. The score provided by the IRAT answers two questions: 1 What is the risk that a virus that is novel in humans could result in sustained human to human transmission? Results from the IRAT have helped public health experts target pandemic preparedness resources against the greatest disease threats and to prioritize the selection of candidate vaccine viruses and the development of pre-pandemic vaccines against emergent viruses with the greatest potential to cause a severe pandemic.

When pre-pandemic vaccines are made, they are stored in the Strategic National Stockpile, along with facemasks, antiviral drugs and other materials that can be used in case of a pandemic. All of these resources, tools, technologies, programs and activities are excellent tools for pandemic planning, and pandemic planning itself has improved significantly since The World Health Organization WHO has published instructions for countries to use in developing their own national pandemic plans, as well as a checklist for pandemic influenza risk and impact management.

Planners have access to other materials as well. For example, in , CDC published a pandemic framework with six intervals that fall within a pandemic curve. Each interval helps with prioritizing data collection, government resources and interventions, and other important activities during the pandemic.

In addition, CDC experts have devised a Pandemic Severity Assessment Framework that uses data to assign severity and transmissibility scores to pandemics. The tool is useful for planning purposes and for determining appropriate mitigations based on the severity of a pandemic. In addition, guidelines for non-pharmaceutical interventions , such as closing schools and large social gatherings, have been established and revised, for use during a pandemic.

While all of these plans, resources, products and improvements show that significant progress has been made since , gaps remain, and a severe pandemic could still be devastating to populations globally. In , the world population was 1.

One hundred years later, the world population has grown to 7. This expanded number of hosts provides increased opportunities for novel influenza viruses from birds and pigs to spread, evolve and infect people. Global movement of people and goods also has increased, allowing the latest disease threat to be an international plane flight away. Due to the mobility and expansion of human populations, even once exotic pathogens, like Ebola, which previously affected only people living in remote villages of the African jungle, now have managed to find their way into urban areas, causing large outbreaks.

If a severe pandemic, such as occurred in happened today, it would still likely overwhelm health care infrastructure, both in the United States and across the world. Such an event would require significant increases in the manufacture, distribution and supply of medications, products and life-saving medical equipment, such as mechanical ventilators. Businesses and schools would struggle to function, and even basic services like trash pickup and waste removal could be impacted.

The best defense against the flu continues to be a flu vaccine, but even today, flu vaccines face a number of challenges. One challenge is that flu vaccines are often moderately effective, even when well matched to circulating viruses.

But perhaps the biggest challenge is the time required to manufacture a new vaccine against an emerging pandemic threat. Generally, it has taken about 20 weeks to select and manufacture a new vaccine. During the H1N1 pandemic, the first doses of pandemic vaccine did not become available until 26 weeks after the decision to manufacture a monovalent vaccine.

The HHS Pandemic Influenza Plan has a goal of reducing the timeframe to make a pandemic flu vaccine from 20 weeks to 12 weeks, but accomplishing this is challenging. One possible solution is to create more broadly protective and longer lasting vaccines. In the meantime, health officials seek to get the most out of new and existing flu vaccine technologies, such as cell based and recombinant vaccines, which are not reliant on a supply of chicken eggs, like traditional vaccines, and have the potential to be produced faster.

One other vaccine issue is the inadequate global capacity for mass producing flu vaccines. Global pandemic flu vaccine capacity was estimated to be 6. Other challenges at a global level include surveillance capacity, infrastructure and pandemic planning.

The majority of counties that report to the WHO still do not have a national pandemic plan, and critical and clinical care capacity, especially in low income countries, continues to be inadequate to the demands of a severe pandemic.

All of these issues show that more work needs to be done, both here in the United States and internationally, to prepare for the next pandemic. Centers for Disease Control and Prevention, hosted a one-day symposium on the year anniversary of the influenza pandemic. The event involved experts from government and academia discussing current pandemic threats and the future of pandemic preparedness, influenza prevention and control.

For more information about influenza pandemics, see Pandemic Influenza. Though rare, completely new versions of the virus may infect people and spread quickly, resulting in pandemics an infection that spreads throughout the world with death tolls in the millions.

Symptoms of the flu include sudden onset fever, coughing, sneezing, a runny nose, and severe malaise, though it can also include vomiting, diarrhea and nausea. Influenza has plagued humankind for centuries and, given its highly variable nature, may continue to do so for centuries to come. Influenza is a viral respiratory infection that causes symptoms similar to, but more severe than, the common cold. Flu symptoms can include sudden onset fever, cough, runny or stuffy nose and severe malaise feeling unwell.

The flu can also sometimes cause vomiting, diarrhea and nausea, particularly in young children , but the flu is primarily a respiratory disease and not a stomach or intestinal disease.

Symptoms develop 1 to 4 days after contracting the virus. Most people recover within 2 weeks without medical treatment, but the flu can cause serious complications, including pneumonia, bronchitis and sinus and ear infections.

Each year, flu epidemics cause 3 to 5 million cases of severe illness and about , to , deaths around the globe, according to the World Health Organization WHO. During recent years in the United States, between 12, and 56, people have died annually from the flu, according to the Centers for Disease Control and Prevention CDC.

Influenza has likely been around for millennia, though its cause was only identified relatively recently. One of the earliest reports of an influenza-like illness comes from Hippocrates , who described a highly contagious disease from northern Greece ca. In , French chroniclers used similar terms to describe an epidemic that affected up to , people in Paris.

The term influenza became commonplace to describe the disease, at least in Britain, in the mids. At the time, it was thought that the influence of the cold influenza di freddo , along with astrological influences or the conjunction of stars and planets influenza di stelle , caused the disease.

In , Dr. Richard Pfeiffer isolated an unknown bacterium from the sputum of his sickest flu patients, and he concluded that the bacteria caused influenza. Scientists later discovered that H. Researchers finally isolated the virus that causes flu from pigs in , and from humans in The specific virus is recognized by these antigens. For example, H1N1 refers to influenza A virus with hemagglutinin subtype 1 and neuraminidase subtype 1, and H3N2 refers to influenza A virus with hemagglutinin subtype 3 and neuraminidase subtype 2.

Influenza B, on the other hand, is recognized by lineages and strains. Influenza is a constantly evolving virus. It quickly goes through mutations that slightly alter the properties of its H and N antigens.

Due to these changes, acquiring immunity either by getting sick or vaccinated with a flu shot to an influenza subtype such as H1N1 one year will not necessarily mean a person is immune to a slightly different virus circulating in subsequent years. It can also occur if an intermediate host such as a pig—which is susceptible to avian, human, and swine influenza—becomes simultaneously infected by influenza viruses from two different species and the viruses exchange genetic information to acquire completely new antigens, a process called genetic reassortment.

The flu spreads several ways: through airborne coughs or sneezes, through touching contaminated surfaces like doorknobs or keyboards, through contact like handshakes or hugs and from saliva shared through drinks or kissing.

If you become sick, consider working or studying from home while recovering, as going to work or school can spread the disease to others. The elderly, young children, pregnant women, people with chronic disease and those with compromised immune systems are more likely to get the flu. The CDC says the flu vaccine is the most effective way to prevent the flu, though it is not foolproof.

Avoiding close contact with sick individuals, covering coughs and sneezes, and washing your hands often can help prevent the flu. Once someone has contracted the flu, doctors can prescribe antiviral medication to shorten the illness and decrease symptoms.

Pinpointing pandemics from historical reports is challenging given the lack of accurate and consistent records, but epidemiologists generally agree that the influenza outbreak is the earliest known pandemic. When the bacterium was injected into other pigs, though, it did not generate disease. Forced to rethink, Shope referred back to some earlier research by Rockefeller Institute scientists Peter Olitsky and Frederick Gates and used their technique to finally isolate a virus that when injected into healthy hogs caused influenza.

The bacterium which coincided with the flu in so many cases turned out to be an opportunistic follower-on which attacked subjects with a secondary infection after the virus had already weakened their defenses.

Shortly after Shope published his swine results, other scientists using his technique isolated the human flu virus. The path was opened to lifesaving flu vaccinations.