Friday February 28, 2020

Experimental Vaccine for Swine Fever Virus Shows Promise

When they deleted this gene, ASFV-G was completely attenuated

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Pigs, Swine Fever, Asia
Almost 5 million pigs in Asia have now died or been culled because of the spread of African swine fever over the past year, the United Nations Food and Agriculture Organisation said on Friday, warning Asian nations to keep strict control measures in place. Pixabay

Researchers have developed a vaccine against African swine fever that appears to be far more effective than previously developed vaccines.

Currently, there is no commercially available vaccine against African swine fever, which has been devastating the swine industry in Eastern Europe and Southeast Asia.

African swine fever virus (ASFV) is highly contagious and often lethal to domestic and wild pigs, according to the the study, published in the Journal of Virology.

“This new experimental ASFV vaccine shows promise, and offers complete protection against the current strain currently producing outbreaks throughout Eastern Europe and Asia,” said study researcher Douglas P Gladue from Plum Island Animal Disease Center, Agricultural Research Service, US Department of Agriculture.

The research was motivated by the 2007 outbreak of African swine fever in the Republic of Georgia.

“This was the first outbreak in recent history outside of Africa and Sardinia–where swine fever is endemic–and this particular strain has been highly lethal and highly contagious, spreading quickly to neighboring countries,” Gladue said.

“This is also a new strain of the virus, now known as ASFV-G (the G stands for Georgia),” Gladue added.

chinese pork, african swine fever
Pigs stand in a barn at a pig farm in Jiangjiaqiao village in northern China’s Hebei province on May 8, 2019. Pork lovers worldwide are wincing at prices that have jumped by up to 40 percent as China’s struggle to stamp out African swine fever in its vast pig herds sends shockwaves through global meat markets. RFA

For the findings, researchers set out to develop a vaccine. Part of the process of developing whole virus vaccines involves deleting virulence genes from the virus.

But when the researchers deleted genes similar to those that had been deleted in older ASFV strains to attenuate them, “it became clear that ASFV-G was much more virulent” than the other, historical isolates, because it retained a higher level of virulence, said Gladue.

The researchers then realised they needed a different genetic target in order to attenuate ASFV-G.

They used a predictive methodology called a computational pipeline to predict the roles of proteins on the virus. The computational pipeline predicted that a protein called I177l could interfere with the immune system of the pig.

Also Read: Indoor Dust Bacteria Have Transferrable Antibiotic Resistance Genes, Says Study

When they deleted this gene, ASFV-G was completely attenuated.

In the study, both low and high doses of the vaccine were 100 per cent effective against the virus when the pigs were challenged 28 days post-inoculation, the researchers said. (IANS)

Next Story

WHO Committee Warns About Ebola Outbreak in Congo

Ebola in Eastern DRC Remains Global Health Threat

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Medical workers lead a young girl with suspected Ebola into the unconfirmed Ebola patients ward run by The Alliance for International Medical Action (ALIMA). VOA

A World Health Organization Emergency Committee warns the Ebola outbreak in eastern Democratic Republic of Congo remains a global health threat despite significant progress in containing the spread of this deadly virus.   WHO reports a total of 3,431 cases of Ebola, including 2,253 deaths in North Kivu and Ituri provinces.

The Emergency Committee declared the outbreak in DRC a Public Health Emergency of International Concern, or PHEIC, last July.  In reviewing the current situation, members of the Committee decided it was premature to declare the global threat over.

WHO Director-General, Tedros Adhanom Ghebreyesus, says he accepts the Committee’s advice.

“As long as there is a single case of Ebola in an area as insecure and unstable as eastern DRC, the potential remains for a much larger epidemic,” he said.

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Director-General of the World Health Organization (WHO) Tedros Adhanom Ghebreyesus speaks during a news conference after a meeting of the Emergency Committee on the novel coronavirus (2019-nCoV) in Geneva, Switzerland. VOA

WHO has revised its risk assessment from very high to high at national and regional levels, and low at the global level.  Last week, it reports only three new cases of the disease in North Kivu’s Beni Health Zone.  Tedros calls these signs extremely positive.

“But even as we near the end of this outbreak, we must act now to prevent the next one…Only half of health facilities have access to water.  Strengthening a health system may not be as sexy as responding to an outbreak, but it is equally important,” he said.

Tedros is traveling to DRC’s capital Kinshasa on Thursday.  The WHO chief says he will meet President Felix Tshisekedi and other senior ministers to explore ways to strengthen DRC’s health system.

Chair of the Emergency Committee, Robert Steffen explains why the group decided to maintain the PHEIC despite cautious optimism that the Ebola epidemic was winding down.

Also Read- US Health Officials Prepare to Battle Flu Season as Coronavirus Fear Rises

“We do see a risk of some resurgence and also a risk of complacency if we would now suddenly abandon this PHEIC despite of the fact that we still occasionally still see new cases,” he said.

Another problem, Steffen says, is lack of money.  He says WHO needs $83 million to carry out its Ebola operation until June.  So far, less than half of the required amount has been received. (VOA)