Decimating the international pig industry, ASF has been reported in more than 55 countries, with China particularly affected. Although it doesn’t impact humans, it is highly contagious and can be spread via contaminated feed and pork products, as well as shoes, clothes, vehicles, knives, equipment, the movement of infected livestock and across wild boar populations.
First reported in Frontiers in Veterinary Science, the potential vaccine looks to tackle the latter form of exposure although further studies are needed.
“African Swine Fever is of enormous concern to the pig industry,” said Dr Jose Angel Barasona, a researcher at the VISAVET Health Surveillance Centre in Madrid and co-author of the study. “Our study demonstrates the effectiveness of the first oral vaccine against this disease on Eurasian wild boar. Overall, we demonstrate that oral immunisation of wild boar conferred 92% protection against a highly pathogenic strain of African Swine Fever, which is currently circulating in Asia and Europe.
“Wild boar is the most severely affected by this virus in Europe and, to date, none of the control measures have been effective,” he said. “The importance of vaccinating wild boar was demonstrated during the 2000s when Classical Swine Fever affected different European countries, and an oral vaccine was used to reduce the incidence of infection in the wild populations in Germany.”
In the research, detailed in full here, it was revealed that a pig in Latvia proved to be key to developing the vaccine.
“Serum from a wild boar hunted in Rietumpieriga, Latvia, was confirmed as African Swine Fever Virus positive at the EU reference laboratory in Madrid, Spain,” said Barasona. “This was a weakly virulent strain of the disease, which enabled us to produce a live vaccine. When we inoculated wild boar in our laboratories with this live strain, they showed no symptoms of this disease, but produced antibodies against the virus, ultimately giving them protection against the more dangerous form.”
Barasona added that the vaccine’s effects could also be passed on via contact. “The ‘shedding’ of this vaccine might help amplify vaccination coverage, reducing the need for expensive production and large-scale administration of vaccine in the field,” he said.
“If the safety of the vaccine can be established, then it may help mitigate the uncontrolled spread of African Swine Fever across Europe and Asia, like the success so far in halting the spread of Classical Swine Fever. Future studies should examine the vaccine’s safety following repeated administration, the process of ‘shedding’, and its genetic stability during passage from one animal to another.”