Friday, 28 December 2012

Wuhan researchers develop oral vaccine for rabies

Affordable vaccine may help prevent rabies deaths in China
by Michael Woodhead
Researchers from Wuhan have helped develop a new vaccine for rabies that is based on the virus that causes kennel cough.
Publishing their research in the Journal of Virology, scientists from the State-key Laboratory of Agricultural Microbiology at the College of Veterinary Medicine, Huazhong Agricultural University, Wuhan say that untreated rabies virus infection is fatal and the disease causes 55,000 deaths a year. They note that vaccine and post-exposure treatment are effective in preventing rabies, but rabies vaccination and treatment have not been widely used in developing countries due to the high cost.
To try develop an effective and cost effective rabies vaccine they tried a new approach by using Parainfluenza virus 5 as a vaccine vector.  They note that Parainfluenza virus 5 is thought to contribute to kennel cough and kennel cough vaccines containing live PIV5 have been used in dogs for many years.
Therefore they tested a PIV5-vectored rabies vaccine in mice. A recombinaint PIV5 encoding RABV glycoprotein (G) (rPIV5-RV-G) was administrated to mice via intranasal (IN), intramuscular (IM) and oral inoculation. They found that  a single dose of the new vaccine was sufficient for 100% protection when administrated intranasally. The intramuscular route also provided very robust protection (90%-100%) against rabies. And intriguingly, the mice vaccinated orally with a single dose of vaccine showed a  50% survival rate, which is comparable to the 60% survival rate sen with the attenuated rabies vaccine.
"This is first report of an orally effective rabies vaccine candidate in animals based on PIV5 as a vector. These results indicate the rPIV5-RV-G is an excellent candidate for a new generation of recombinant rabies vaccine for humans and animals and PIV5 is a potential vector for oral vaccines," they conclude.
Source: Journal of Virology

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