NEWS ▶▶▶ Nipah vaccines show promising results

Two newly developed potential vaccines against Nipah virus generate a strong immune response in pigs, which is promising news for protection against the virus. That was the mes- sage of newly published research in the peer-reviewed title Vaccines, authored by re- searchers from the United Kingdom, Italy, France and Australia. They trialled vaccines de- veloped by the University of Parma, Italy. In the UK, the Pirbright Institute participated in the research. On its website, the institute ex- plained: “The promising results suggest the vaccines could protect pigs against Nipah virus infection, which can cause respiratory prob- lems and fatal encephalitis in pigs and hu- mans. By preventing spread of the virus through pig populations, the novel vaccines would also lower the chances of humans con- tracting the disease.” The two vaccine candidates generated strong antibody and cellular immune responses in pigs. Since it is thought that both types of im- mune response are important for protection against Nipah virus, these results are said to provide a solid basis for their further

US study to focus on pig enrichment

investigation in vaccine development for use in pigs and potentially other species. To create the vaccines, the scientists genetical- ly engineered bovine herpes viruses (BoHV-4) to deliver Nipah virus proteins to pigs. The team selected the G and F proteins that Nipah virus is known to use to enter cells and facili- tate cell-to-cell spread. When presented to the immune system, these proteins trigger a re- sponse that prepares the host to fight the in- fection. Spread of the virus from pigs to hu- mans caused a human Nipah outbreak in Malaysia in the 1990s.

China: New ASF vaccine is effective

China’s Harbin Veterinary Research Institute stated it has developed a vaccine to African Swine Fever (ASF) which according to lab test- ing is safe and effective. Researchers achieved this by deleting seven gene segments from the virus. The discovery was shared in an article in Science China Life Sciences. The Harbin Institute said deleting a series of genes from the virus created a live vaccine with reduced virulence. It did not mention when a commercial vaccine might be available. The researchers used China’s first ASF virus iso- late, called HLJ/18, as the backbone and con- structed a series of recombinant viruses with different gene deletions using homologous re- combination technology. Six recombinant vi- ruses were made and tested. Through system- atic pathogenicity, immunogenicity and immunoprotective tests in pigs, a virus with seven gene deletions (HLJ/-18-7GD) was se- lected because it met the safety standards for live attenuated vaccines, which can be used in

pigs. Trials included various rounds with specif- ic-pathogen-free pigs as well as sows. Similar research was performed by the US Ag- ricultural Research Service (ARS) in 2015. At that stage, six of seven genes were deleted. Dr Douglas Gladue of the ARS said to Pig Progress: “The Harbin study utilised our ASFv-G-∆MGF deletion and added an additional deletion of the gene CD2.” The US research at the time also noted that “a proportion of these animals har- boured the challenge virus”, which means that a longer-term recombination could be possi- ble. As a result, the team chose not to include CD2 as an additional deletion in their vaccine platform. He said, “The multigene family genes comprise many genes on either end of the ASFv genome, and this area of the genome is well known to have a high degree of recombi- nation. Consequently, it wasn’t our top choice to pursue it as a vaccine candidate, as there are some potential safety concerns due to the pos- sibility of recombination in this area.”

How can environmental enrichment tech- niques improve pig welfare, health and pro- ductivity? That question is key in a study by researchers at the US Department of Agricul- ture’s Agricultural Research Service (ARS). The study is one of the first of its kind in the US, according to the Foundation for Food and Ag- riculture Research, which awarded a $ 75,000 grant for this research to the ARS. Commercial parties such as Nestlé and Tyson Foods have provided matching funding for a total $ 150,000 investment. Food producer Nestlé was a driving force be- hind the research, as the company is a major producer of frozen pizzas, with Tyson supply- ing toppings such as ham, sausage and pep- peroni. As part of the Global Coalition for Ani- mal Welfare, Nestlé is concerned with product sourcing and social responsibility. Also in- volved in the research is Dr Keelin O’Dri- scoll of the Irish agricultural research authority Teagasc. Dr Jeremy Marchant-Forde, USDA ARS animal scientist, explained to Pig Progress that the tri- als are being done in two stages, the first of which has already been carried out at Purdue University swine unit, USA. In that set, the en- richment situations were compared to one without enrichment, with trials having been held during lactation, nursery and grow-finish phases. The study looked at Easyfix floor and hanging objects, Ikadan bite-rite and Porciplay/Por- cichew objects. The second part will take some of these enrichments out onto Tyson farms. The current coronavirus outbreaks are likely delaying those trials.


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▶PIG PROGRESS | Volume 36, No. 3, 2020 25


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