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Several vials that were labelled "smallpox" and accidentally found at a laboratory in the US state of Pennsylvania raised the alarm for threats of a virus leak to public health, local media has reported. A laboratory worker found 15 vials while cleaning out a freezer in a facility that conducts vaccine research outside Philadelphia, with five labelled "smallpox" and 10 as "vaccinia", Xinhua news agency reported.
Smallpox is a highly infectious disease caused by the variola virus, which claimed the lives of 300 million people in the 20th century, according to the World Health Organization (WHO). A possible leak put the Centers for Disease Control and Prevention (CDC) and the Department of Homeland Security on high alert. Under the WHO agreement, there are only two authorised repositories of live smallpox stocks, the CDC headquarters in Atlanta and a research center in Russia.
The CDC said Thursday that it found no evidence the vials contained the variola virus, and there was no indication that lab workers or the public had been exposed to the contents, without explanations of how the vials ended up in the freezer or if the agency investigated a virus leak. Robert Glatter, an emergency physician at Lenox Hill Hospital in New York, was quoted by The New York Times as saying that smallpox can be lethal "even after it is freeze-dried." (IANS/ MBI)
Keywords: Smallpox, vials, US, lab, virus leak, risks
HIV patients lose immunity to smallpox even though they were vaccinated against the disease as children and have had much of their immune system restored with anti-retroviral therapy, says a new study.
Antiretroviral therapy (ART) is the use of HIV medicines to treat HIV infection. It helps people with HIV live longer, healthier lives and reduces the risk of HIV transmission.
The study, published in the Journal of Infectious Diseases on HIV-associated immune amnesia could explain why people living with HIV still tend to have shorter lives on average than their HIV-negative counterparts despite being on antiretroviral therapy.
The study follows other research recently published in the journals Science and Science Immunology that found the immune systems of children who contracted measles similarly ‘forgot’ their immunity against other illnesses such as influenza.
For the study, lead researcher Mark K. Slifka from Oregon Health and Science University in US, and his colleagues compared the T-cell and antibody responses of a total of 100 HIV-positive and HIV-negative women who were vaccinated against smallpox in their youth.
The research team chose smallpox because its last known US case was in 1949, meaning study participants haven’t recently been exposed to its virus, which would have triggered new T-cell and antibody responses.
They found the immune systems of HIV-positive women who were on antiretroviral therapy had a limited response when their blood was exposed to the vaccina virus, which is used in the smallpox vaccine.
Normally, those vaccinated against smallpox have CD4 T cells that remember the virus and respond in large numbers when they’re exposed again.
Previous research has shown smallpox virus-specific CD4 T cells are maintained for up to 75 years after vaccination.
This finding happened despite the fact that antiretroviral therapy works by boosting CD4 T cell counts in HIV-positive patients.
This indicates that while antiretroviral therapy may boost total T cell counts overall, it can’t recover virus-specific T cells generated from prior childhood vaccinations.
The research team plans to evaluate whether the same phenomenon occurs in HIV-infected men, and if people living with HIV also lose immune memory to other diseases.
Researchers from SUNY Downstate, Georgetown University, Cornell University, University of Southern California and John Hopkins University, also contributed to this study. (IANS)
Scientists discover Genetic Evidence of Smallpox from remains of 17th-century Mummy found in Crypt beneath a Lithuanian Church
Dec 9, 2016: Scientists have discovered genetic evidence of smallpox from the remains of a 17th-century mummy found in a crypt beneath a Lithuanian church. The early DNA provides a timeline of the highly infectious disease that was finally eradicated in the 20th century.
The mummy is of the lower half of a child. Samples of the mummy’s skin were taken by Canadian and Australian researchers, who were then able to reconstruct the decomposing genome of the virus.
The mummified child, one of several bodies found in the 400-year-old crypt, provides the first conclusive evidence of smallpox in humans.
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Before the discovery, it was thought that the ancient Egyptian pharaoh, Ramses V, was the earliest example of smallpox because of what scientists assumed were pox marks found on the remains. But it is so far been impossible to get DNA from a 3,000- to 4,000-year-old mummy.
The child’s body had no such scarring, so the discovery surprised Hendrik Poinar, Director of the Ancient DNA Center at McMaster University in Ontario.
“We were using these mummies as a good test to looking back in time for the potential sort of deep time travel with viruses,” he said. “And so we tried to pull out all the viruses and we looked at the reads that we found and, lo and behold, there was variola – some reads of variola – and we thought, ‘Oh, that can’t be.’”
Two strains of smallpox
Widespread vaccination eliminated smallpox or variola virus as a human scourge in 1977.
By reconstructing the 17th century DNA and comparing it to genomes dating to the mid-1900s and genetic material before variola’s eradication in the 1970s, the scientists concluded the samples shared a common viral ancestor that originated between 1588 and 1645.
In addition to providing a timeline of smallpox, scientists believe they have pinpointed its evolution. They think two strains branched off from a common ancestor around the time that a variola vaccine was created in the 1800s by Edward Jenner. They suggest the vaccine caused pressure on the smallpox virus, leading to mutations that separated it into two strains, variola major and variola minor. One caused more severe disease than the other.
The time period when the strains branched apart, according to Poinar, coincides in history with human exploration, migration and colonization, activities that would have caused smallpox to spread around the world.
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Even though smallpox has been eradicated and is no longer a health threat, Poinar thinks it’s important to have a timeline for diseases to see how they evolve and progress, something that could be important for treatment and eradication.
“I don’t think these sorts of studies are navel gazing exercises,” said Poinar. “I think they can shed important light on the evolutionary tempo and mode of these infectious agents, and I think that’s important to understand.”
The findings reveal that the smallpox virus is most closely related to variola virus in camels and gerbils, although researchers don’t know specifically what animal the human version came from.
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Poinar and colleagues had to obtain permission to conduct their work from the World Health Organization because of concerns that the research could reawaken the virus, something Poinar said degraded DNA from a mummified child could not do.
The discovery was published in the Cell press journal Current Biology. (VOA)