Tamiflu is one of the few available treatments for those who come down with the flu. But the virus quickly develops resistance; multiplying at a rate of several generations a day, these tiny pathogens rapidly accumulate genetic mutations. Because of this, they have a good chance of developing counterattacks to the antiviral. How can these infinitesimal variations be identified within the immensity of the virus’ genetic code? EPFL researchers have created a computer tool that can shed light on the flu virus’ formidable adaptability. They were able to find mutations that conferred resistance that had up to this point not yet been identified. Their software has been made freely available to researchers everywhere, and is the subject of an article published in the journal PLOS Genetics.
Widespread use of Tamiflu leads to resistance
In theory, Tamiflu should only be used by patients in fragile health. But during the 2008-2009 flu season, the drug was used for the first time on a very wide scale. Resistant strains of the virus appeared within just a few weeks. Fortunately, even though the mutation induced a resistance to Tamiflu, it also caused a reduction in the replication rate of the virus. Once the use of the antiviral was dialed back to a more reasonable level, the resistant strains lost their competitive advantage, and they disappeared, submerged by competitors that were sensitive to the drug but had a higher rate of replication.
Resistance always results from random mutations, says Jeffrey Jensen, co-author of the EPFL study. But when a mutation leads to a competitive advantage, for example the ability to resist against a source of aggression, it tends to be passed on to its descendants. “A priori, nothing distinguishes one mutation from another; they’re all the result of chance. Our goal is precisely to be able to tell the difference between mutations that make the virus resistant to Tamiflu, thus leading to a selection phenomenon, and other mutations.”
Reducing glucose metabolism dials down influenza viral infection in laboratory cell cultures, providing an entirely new approach for combating seasonal flu, according to research that will be presented on Sunday, Dec. 15, at the American Society for Cell Biology (ASCB) annual meeting in New Orleans.
While annual flu shots are based on the U.S. Centers for Disease Control (CDC)‘s predictions of the viruses that will be in widest circulation each flu season, the new approach targets one metabolic requirement of all influenza viruses: glucose.
Reducing viruses’ glucose supply weakens the microbes’ ability to infect host cells, said Amy Adamson, Ph.D., and Hinissan Pascaline Kohio of the University of North Carolina, Greensboro.
Fever, ache, and the other miseries of influenza viral infection afflict 5 to 20 percent of the U.S. population each year. While the flue is usually not life-threatening to the majority of its victims, the Spanish flu pandemic of 1918 demonstrated that flu viruses can evolve into lethal agents that spread worldwide. Because flu viruses change continually through mutation and genetic swaps, the CDC reformulates the flu vaccine each year.
Mice given a drug commonly used in patients to fight systemic fungal infections more often succumb to what would otherwise be a mild case of the flu. The evidence reported in the Cell Press journal Cell Reports on November 21st shows that the drug called Amphotericin B, which has an estimated $330 million in sales around the world each year, can render a protein important for antiviral defense ineffective in both cells and mice.
The findings suggest that patients receiving the antifungal therapy may be functionally immunocompromised and more vulnerable to influenza and other viral infections, the researchers said.
“Many critically ill cancer and bone marrow transplant patients are treated with Amphotericin B-based therapies each year,” said Abraham Brass of the University of Massachusetts Medical School (UMMS). “Given these results in cells and mice, it may be worthwhile to consider that patients receiving, or who may receive, Amphotericin B-based therapies be appropriately vaccinated against influenza virus. Also, clinical consideration may be given to close monitoring of patients receiving Amphotericin B-based therapies for any symptoms suggestive of flu so that they might be considered for the early administration of an antiflu therapy.”
The researchers showed that Amphotericin-B prevents the antiviral protein in cells known as IFITM3 from fending off influenza A virus.
Scientists in the Dutch city of Rotterdam know precisely what it takes for a bird flu to mutate into a potential human pandemic strain - because they’ve created just such mutant viruses in the laboratory.
So as they watch with some trepidation the emergence in China of a strain of bird flu previously unknown in humans, they also argue it vindicates their controversial decision to conduct these risky experiments despite fierce opposition.
Above all else, what the world needs to know about this new strain of H7N9 bird flu is how likely it is to be able to spread efficiently among human populations.
Bird flu may be far less lethal to people than the World Health Organization’s assessment of a death rate topping 50 percent, scientists said on Thursday in a finding that adds fuel to the heated controversy over publication of bird flu research.
Scientists led by virologist Peter Palese of Mount Sinai School of Medicine in New York argue in an analysis published in the online edition of the journal Science that the WHO, a U.N. agency, is calculating the death rate using an estimate of human bird flu cases that is simply too low.
Palese and his colleagues did not offer a specific death rate for people infected by bird flu. But based on figures cited in their analysis, the rate appears to be under 1 percent.
A man in southwest China died of bird flu on Sunday after three days of intensive care treatment in hospital, the official Xinhua news agency quoted the Ministry of Health as saying.
The 39-year old—who died in hospital in Guiyan, capital of Guizhou province—began suffering from fever on January 6.
Xinhua said China’s centers for disease control and prevention at provincial and national levels confirmed the man had died after being infected with the H5N1 bird flu strain.
The second wave of the pandemic (H1N1) was substantially greater than the first with 4.8 times more hospital admissions, 4.6 times more deaths and 4 times more ICU cases, according to a study published in CMAJ (Canadian Medical Association Journal) (pre-embargo link only) http://www.cmaj.ca/embargo/cmaj100746.pdf. However, because of the larger number of people hospitalized during the second wave compared to the first, the percentage of people with severe outcomes was smaller.
The researchers compared demographic and clinical characteristics as well as outcomes of patients with (H1N1) influenza admitted to hospital during the first wave with those admitted during the second wave and post-peak period of the pandemic.
In the first wave, Nunavut, Manitoba and Quebec had the highest rates for hospital admissions. In the second wave, all provinces and territories were affected with the Maritimes provinces, Alberta, British Columbia, the Yukon Territory and the Northwest Territories experiencing much higher rates of hospital admission than in the first one. Quebec and Ontario were impacted in both waves, with Quebec reporting the highest number of hospitalizations and Ontario reported the most deaths overall.
Now that the H1N1 influenza pandemic is officially over, what will happen to the virus? In a perspective article published today in the online open-access journal mBio®, scientists from the National Institutes of Health delve into history and explore the fates of other pandemic influenza viruses in order to speculate on the future of the most recent pandemic virus.
“While human influenza viruses have often surprised us, available evidence leads to the hope that the current pandemic virus will continue to cause low or moderate mortality rates if it does not become extinct,” write Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases (NIAID) and his NIAID coauthors, Jeffery Taubenberger and David Morens.
The impact of the virus in the upcoming influenza season will depend directly on the degree of existing immunity in the population, provided the virus does not undergo any changes. The authors currently estimate that approximately 59% of the United States population has some level of immunity due to either exposure to the pandemic H1N1 (pH1N1) virus, vaccination or exposure to a closely related influenza virus. That number will continue to increase through immunization with the 2010-2011 seasonal influenza vaccines, which will contain the pH1N1 strain.
The human body makes rare antibodies effective against all flu viruses and these might be boosted to design a better universal flu treatment, researchers reported on Monday.
Tests on mice suggest these immune system proteins could help most people survive a normally lethal dose of flu virus, the team at the University of Wisconsin and Seattle-based Theraclone Sciences said.
“The ability of these antibodies to protect mice from highly lethal strains of influenza is encouraging,” said Yoshihiro Kawaoka, a flu expert at the University of Wisconsin-Madison and University of Tokyo who worked on the study, said in a statement.
An experimental drug being developed to fight influenza may fight a common but little-known virus called parainfluenza virus, researchers and the company said on Friday.
Tests in rats showed Fludase, made by privately held NexBio, could stop parainfluenza viruses from replicating, the researchers reported in the Journal of Infectious Diseases.
Dr. Anne Moscona of Weill Cornell Medical Center in New York and colleagues tested varying doses of the drug, also known as DAS181, in lab dishes and on cotton rats, a species accepted by scientists for testing parainfluenza.
A group of independent experts will review how the H1N1 pandemic has been handled to ensure that the next global health emergency is dealt with better, a top World Health Organisation official said on Monday.
The H1N1 influenza outbreak, which began in April last year, was marked by controversies over whether the WHO and public health authorities had exaggerated the risks of H1N1 and created unnecessary alarm by declaring it a ‘pandemic’.
The WHO has also been criticised for its pandemic alert system that focuses on geographical spread of the outbreak rather than its severity, and on alleged conflicts of interests between health officials and experts and vaccine makers.
Washing out your nose with a spray or spout of salt water is safe and might even get you back to work sooner after a cold or acute sinus infection. However, there is not enough evidence to show that it can reduce your symptoms significantly, according to a new research review.
The three studies in the review included small numbers of patients and varied widely in their details, “which means small beneficial effects may be missed,” said lead author David King, M.D., of the University of Queensland, in Australia.
One study found that people were more likely to return to work sooner after using the nose washes, and there was some intriguing evidence that nasal washes might reduce antibiotic prescriptions among those who seek the saltwater treatment.
Romania has identified an outbreak of bird flu at a poultry farm close to Ukraine and enforced a 20 kilometre-wide surveillance zone around it, the European Union’s executive said on Tuesday.
The outbreak of the H5N1 virus in the commune of Letea near the Ukrainian border is the first detected in Europe since it was found in a wild duck in Germany a year ago.
“Romania’s national laboratory confirmed yesterday that the outbreak concerns the highly pathogenic H5N1 strain of avian influenza,” the European Commission said in a statement.
The coming year’s seasonal flu vaccine in the northern hemisphere should include protection against three strains of flu, including the pandemic H1N1 virus, the World Health Organization recommended on Thursday.
The composition of the vaccine, announced at the end of a closed-door four-day meeting of influenza experts that is closely followed by the world’s vaccine makers, means governments that have stockpiled doses of H1N1 swine flu vaccine may now use them for part of the seasonal flu vaccine mix.
Some countries, including Germany, France and the United States, cut back their orders of the H1N1 swine flu jab after people were slow to take them up. The fact that people needed only one dose, and not two as originally thought, also contributed to oversupply.
South Africa faces a possible health crisis if a swine flu outbreak strikes during the soccer World Cup this year, Health Minister Aaron Motsoaledi told parliament on Monday.
“One of our biggest nightmares is the fact that 2010 is going to be held in June when there is a possibility of another bout of H1N1,” Motsoaledi said.
The month-long tournament, hosted in Africa for the first time, is expected to attract 450,000 tourists during the South African winter.