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Showing posts with label Virus. Show all posts
Showing posts with label Virus. Show all posts

Wednesday, August 14, 2013

Rabies Virus Hid in Organ Donor, Surfaced in Recipient

A Maryland man who died from rabies after receiving a kidney from an infected donor is the eighth known victim of rabies-tainted solid-organ transplants, according to a new report.

The man, whose name and age have not been released, developed brain inflammation known as encephalitis in February, 17 months after the transplant, according to the report published today in the Journal of the American Medical Association. He died 26 days later.

At the time of the transplant, the organ donor was brain dead from what doctors thought was ciguatera, a form of food poisoning caused by contaminated fish. That he had recently been bitten by two raccoons, the most frequently reported rabid animal in the United States, went unreported until after the transplant, according to the report.

"This transmission event provides an opportunity for enhancing rabies awareness and recognition and highlights the need for a modified approach to organ donor screening and recipient monitoring for infectious encephalitis," the authors wrote.

Read about how CDC scientists traced the kidney recipient's death to the tainted transplant.

The donor fell ill after a fishing trip, developing nausea and tingling in his arms, signs of both rabies and ciguatera. But brain scans taken before his death failed to find signs of encephalitis, the hallmark of rabies, leading doctors to determine there was "no increased risk for infectious disease transmission," according to the report.

His heart, liver and kidneys were transplanted into four people.

An autopsy independent of the organ procurement soon determined ciguatera to be "extremely unlikely" in the donor's death, which was ultimately blamed on "complications of severe gastroenteritis," according to the report.

A year and a half later, after the death of the kidney recipient, post-mortem testing of the kidney and brain tissue from the donor revealed the same strain of raccoon rabies. It's unclear whether the hospital or anyone involved in the transplant was reprimanded. The names have not been released.

Disease transmission from transplanted organs is rare, according to Dr. Michael Green, chairman of the Organ Procurement and Transplantation Network and United Network for Organ Sharing's Ad Hoc Disease Transmission Committee.

"That said, for any individual potential organ donor and potential organ recipient, the risk of a potential disease transmission must be weighed against the potential adverse outcomes associated with not getting a transplant," said Green, who is also a professor of surgery at the University of Pittsburgh School of Medicine.

"The organ procurement organizations have careful screening procedures, and the transplant community works together to constantly enhance patient safety," Green added. "The lessons we learn from this experience help to improve policies and enhance the transplant community's understanding with a goal of decreasing the risk to transplant recipients as much as possible."

Read about a teen who died from rabies after being bitten by a vampire bat.

Human rabies is rare in the United States, killing roughly two Americans per year. While thousands might be exposed to the virus through contact with raccoons, dogs or bats, drugs designed to prevent the deadly infection are nearly 100 percent successful, according to the U.S. Centers for Disease Control and Prevention.

The three people who received the donor's heart, liver and other kidney were given treatment and remain symptom-free, according to the report.

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Thursday, June 27, 2013

Virus Combination Effective Against Deadly Brain Tumor, Moffitt Cancer Center Study Shows

Main Category: Cancer / Oncology
Also Included In: Neurology / Neuroscience
Article Date: 24 Jun 2013 - 1:00 PDT Current ratings for:
Virus Combination Effective Against Deadly Brain Tumor, Moffitt Cancer Center Study Shows
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A combination of the myxoma virus and the immune suppressant rapamycin can kill glioblastoma multiforme, the most common and deadliest malignant brain tumor, according to Moffitt Cancer Center research. Peter A. Forsyth, M.D., of Moffitt's Neuro-Oncology Program, says the combination has been shown to infect and kill both brain cancer stem cells and differentiated compartments of glioblastoma multiforme.

The finding means that barriers to treating the disease, such as resistance to the drug temozolomide, may be overcome. The study, by Forsyth and colleagues in Canada, Texas and Florida, appeared in a recent issue of Neuro-Oncology.

"Although temozolomide improves survival for patients with glioblastoma multiforme, drug resistance is a significant obstacle," said Forsyth, the study lead author. "Oncolytic viruses that infect and break down cancer cells offer promising possibilities for overcoming resistance to targeted therapies."

The authors note that oncolytic viruses have the potential to provoke a multipronged attack on a tumor, with the potential to kill cancer cells directly through viral infection and possibly through inducing the immune system to attack the tumor. The multipronged approach might get around some of the classical resistance mechanisms that have plagued both targeted therapies and conventional chemotherapies.

Several oncolytic viruses, both alone or in combination with small molecule inhibitors, have been tested and show promise for malignant gliomas. However, most have not been effective in killing cancer cells. Two likely obstacles may be the patient's own anti-viral immune response and limited virus distribution.

"Based on our previous work with myxoma virus, we considered it to be an excellent oncolytic virus candidate against brain cancer stem cells," explained Forsyth.

The researchers found that brain cancer stem cells were susceptible to myxoma virus in the laboratory cultures (in vitro) and in animal models (in vivo), including in temozolomide-resistant cell lines.

"We also found that myxoma virus with rapamycin is a potentially useful combination. The idea that cancer cells can be killed by a harmless virus is an exciting prospect for therapy," Forsyth said.

The precise mechanism rapamycin uses to enhance infection in brain cancer stem cells is unknown, and the combination therapy does not result in cures. However, researchers are investigating other drugs that may improve the effectiveness of myxoma virus when used in combination, and they are evaluating the use of other strains of myxoma virus that might be more effective.

"Although our study adds myxoma virus to the list of oncolytic viruses capable of infecting and killing these cells, which strengthens its candidacy for clinical application, our model will need clinical application to determine its safety for patients," concluded the authors. "We expect that intracranial injections of myxoma virus will be safe based on our extensive preclinical work and the demonstrated safety of other oncolytic viruses in clinical trials."

Article adapted by Medical News Today from original press release. Click 'references' tab above for source.
Visit our cancer / oncology section for the latest news on this subject. This study was supported by grants from the National Institutes of Health (R01 AI080607, R21 CA149869, and R01 CA138541).

Researchers from the University of Florida, University of Calgary, University of Texas and Ottawa Regional Cancer Centre Research Laboratories contributed to this work and publication.

H. Lee Moffitt Cancer Center & Research Institute

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