The U.S. Department of Agriculture’s Agricultural Research Service (ARS) announced on Oct. 6, that an African Swine Fever Virus vaccine candidate has been adapted to grow in a continuous cell line, rather than having to rely on live pigs and their fresh cells.
“This [scientific breakthrough] opens the door for large-scale vaccine production, [not previously possible] which is a valuable tool for the possible eradication of the virus,” said senior ARS scientist Dr. Manuel Borca.
African swine fever (ASF) is a devastating haemorrhagic fever of pigs that causes up to 100% mortality. Fortunately, African Swine Fever is not a threat to humans and cannot be transmitted from pigs to humans. However, it can devastate meat supply. Two years ago, half of China’s swineherd was wiped out by ASF, and the measures needed to combat it. At present it has jumped to the Americas, and is in Haiti and the Dominican Republic.
ASF is caused by a unique DNA virus that is maintained in an ancient cycle between warthogs and argasid ticks, making it the only known DNA arbovirus. Warthogs and tampan ticks transmit ASF to domesticated pigs. A devastating constraint for pig production in Africa, ASF has a high potential for transboundary spread, and has shown up episodically around the world. U.S. authorities are defending against it now, but it could arrive at any time.
The new discovery, highlighted in the Journal of Virology, overcomes one of the major challenges for manufacturing of an African Swine Fever Virus vaccine. The newly developed vaccine, grown in a continuous cell line—in which immortalized cells divide continuously or otherwise indefinitely—has the same characteristics as the original vaccine produced with fresh swine cells.
“Traditionally we used freshly isolated swine cells to produce vaccine candidates and this constitutes a significant limitation for large-scale production” said senior ARS scientist Dr. Douglas Gladue. The vaccine has been tested in commercial pigs in Vietnam, and many other locations, proving efficacy and safety.
