Soon, vaccines for 2 bird flu strains

A new study has detailed vaccine development for two new strains of avian influenza that can be transmitted from poultry to humans.

The Kansas State University's vaccine development method is expected to help researchers make vaccines for emerging strains of avian influenza more quickly, which could reduce the number and intensity of large-scale outbreaks at poultry farms as well as curb human transmission.

It also may lead to new influenza vaccines for pigs, and novel vaccines for sheep and other livestock, said researcher Jurgen Richt.

Richt and his colleagues focused on the avian influenza virus subtype H5N1, a new strain most active in Indonesia, Egypt and other Southeast Asian and North African countries. H5N1 also has been documented in wild birds in the U.S., though in fewer numbers.

H5N1 is a zoonotic pathogen, which means that it is transmitted from chickens to humans, Richt noted, adding that so far it has infected more than 700 people worldwide and has killed about 60 percent of them. Unfortunately, it has a pretty high mortality rate.

Researchers developed a vaccine for H5N1 by combining two viruses. A vaccine strain of the Newcastle disease virus, a virus that naturally affects poultry, was cloned and a small section of the H5N1 virus was transplanted into the Newcastle disease virus vaccine, creating a recombinant virus.

Researchers also looked at the avian flu subtype H7N9, an emerging zoonotic strain that has been circulating in China since 2013. China has reported about 650 cases in humans and Canada has reported two cases in people returning from China. About 230 people have died from H7N9.

The study is published in Journal of Virology.