Archive for the ‘Biological Threats and Virus Risks to General Public’ Category

Fungal Meningitis: Know the Subtle Symptoms

October 17, 2012

ap Meningitis outbreak nt 121005 wblog Fungal Meningitis: Know the Subtle Symptoms

Health officials are urging thousands of back pain patients to be on the lookout for symptoms of fungal meningitis amid an outbreak that has killed at least five people and sickened 42 across seven states.

The outbreak has been linked to spinal steroid injections, a common treatment for back pain. The steroid, called methylprednisolone acetate, was made by the New England Compounding Center, a specialty pharmacy in Framingham, Mass. that has recalled three lots — 17,676 vials — of the drug and shut down operations.

Roughly 75 clinics in 23 states that received the recalled vials have been instructed to notify all affected patients.

See a list of affected clinics

“If patients are concerned, they should contact their physician to find out if they received a medicine from one of these lots,” said Dr. Benjamin Park of the U.S. Centers for Disease Control and Prevention, adding that most of the cases occurred in older adults who were healthy aside from back pain.

Meningitis affects the membranous lining of the brain and spinal cord. Early symptoms of fungal meningitis, such as headache, fever, dizziness, nausea and slurred speech, are subtler than those of bacterial meningitis and can take nearly a month to appear. Left untreated, the inflammatory disease can cause permanent neurological damage and death.

“Fungal meningitis in general is rare. But aspergillus meningitis — the kind we’re talking about here — is super rare and very serious,” said Dr. William Schaffner, president of the National Foundation for Infectious Diseases and chairman of preventive medicine at Vanderbilt University Medical Center in Nashville, Tenn. “There’s no such thing as mild aspergillus meningitis.”

The disease is diagnosed with a lumbar puncture, which draws cerebrospinal fluid from the spine that can be inspected for signs of the disease. Once detected, it can be treated with high doses of intravenous antifungal medications, possibly for months.

Twenty-nine of the meningitis cases — three of them lethal — have been in Tennessee, where more than 900 residents received the drug since July. Cases have also been reported in Virginia, Michigan, Indiana, Maryland, Florida and North Carolina.

Robert Barry, 71, received an injection from one of the recalled vials about six weeks ago.

“They told me that if I begin to develop headache, nausea or trouble walking — if I believe that Obama won the debate — I should go to the emergency room,” said Barry, who lives in Berlin, Md.

Unlike bacterial meningitis, fungal meningitis is not transmitted from person to person. Only people who received the steroid injections are thought to be at risk, but only one in 100 of them have developed signs of the disease.

“At the moment the attack rate appears to be 1 percent or less, but of course more cases are sure to develop,” said Schaffner, adding that the level of contamination may have varied from vial to vial. “Some patients also received more than one dose, which would increase their risk.”

Why Swine Flu Virus Develops Drug Resistance

June 4, 2012

Computer chips of a type more commonly found in games consoles have been used by scientists at the University of Bristol to reveal how the flu virus resists anti-flu drugs such as Relenza and Tamiflu.

Professor Adrian Mulholland and Dr Christopher Woods from Bristol’s School of Chemistry, together with colleagues in Thailand, used graphics processing units (GPUs) to simulate the molecular processes that take place when these drugs are used to treat the H1N1-2009 strain of influenza – commonly known as ‘swine flu’.

Their results, published in Biochemistry, provide new insight that could lead to the development of the next generation of antiviral treatments for flu.

H1N1-2009 is a new, highly adaptive virus derived from different gene segments of swine, avian, and human influenza. Within a few months of its appearance in early 2009, the H1N1-2009 strain caused the first flu pandemic of the 21st-century.

The antiviral drugs Relenza and Tamiflu, which target the neuraminidase (NA) enzyme, successfully treated the infection but widespread use of these drugs has led to a series of mutations in NA that reduce the drugs’ effectiveness.

Clinical studies indicate that the double mutant of swine flu NA known as IRHY2 reduced the effectiveness of Relenza by 21 times and Tamiflu by 12,374 times – that is, to the point where it has become an ineffective treatment.

To understand why the effectiveness of Relenza and Tamiflu is so seriously reduced by the occurrence of this mutation, the researchers performed long-timescale molecular dynamics (MD) simulations using GPUs.

Professor Mulholland said: “Our simulations showed that IRHY became resistant to Tamiflu due to the loss of key hydrogen bonds between the drug and residues in a part of the NA’s structure known as the ‘150-loop’.

“This allowed NA to change from a closed to an open conformation. Tamiflu binds weakly with the open conformation due to poor electrostatic interactions between the drug and the active site, thus rendering the drug ineffective.”

These findings suggest that drug resistance could be overcome by increasing hydrogen bond interactions between NA inhibitors and residues in the 150-loop, with the aim of maintaining the closed conformation.


References:

The research was supported by the Engineering and Physical Sciences Research Council (EPSRC) through a Leadership Fellowship grant to Professor Mulholland and a software development grant to Professor Mulholland and Dr Woods.

Paper:

‘Long Time Scale GPU Dynamics Reveal the Mechanism of Drug Resistance of the Dual Mutant I223R/H275Y Neuraminidase from H1N1-2009 Influenza Virus’ by Christopher J. Woods, Maturos Malaisree, Naruwan Pattarapongdilok,Pornthep Sompornpisut, Supot Hannongbua and Adrian J. Mulholland in Biochemistry Graphics Processing Units (GPUs)

GPUs are providing scientists with remarkable biological insights. They allow new, much longer timescales to be accessed, transforming what is possible in a simulation.

The University of Bristol is part of a new e-Infrastructure South Consortium Centre for Innovation which will shortly open the largest GPU cluster in the UK (and the second largest in Europe), funded by the Engineering and Physical Sciences Research Council (EPSRC).
The other partners in the Centre are University College London, the University of Southampton, the University of Oxford, and the STFC: Rutherford Appleton Laboratory (RAL).


Citations:

Please use one of the following formats to cite this article in your essay, paper or report:

MLA

University of Bristol. “Why Swine Flu Virus Develops Drug Resistance.” Medical News Today. MediLexicon, Intl., 31 May. 2012. Web.
3 Jun. 2012. <http://www.medicalnewstoday.com/releases/245980.php&gt;

APA

University of Bristol. (2012, May 31). “Why Swine Flu Virus Develops Drug Resistance.” Medical News Today. Retrieved from
http://www.medicalnewstoday.com/releases/245980.php.

Please note: If no author information is provided, the source is cited instead.