 African swine fever is a very serious infectious disease that affects domestic pigs and wild pigs. So it was first found in East Africa. It's present in a wildlife reservoir of warthogs and soft ticks that live in warthog burrows. But in the early 1900s it spread to domestic pigs that came in contact with the wildlife. And in the domestic pigs it causes an acute hemorrhagic fever with very high death rates. So since that time the disease spread through sub-Saharan Africa and to Europe twice, 1957-1960. It was eventually eradicated from Europe in the mid-1990s except for Sardinia. But since 2007 disease was introduced into Georgia in the Caucasus region. And from there it spread through the Russian Federation and into Eastern Europe. Most isolates of the virus cause acute hemorrhagic fever. So the clinical signs are at first quite nonspecific. So there's a high fever, loss of appetite, lethargy. At later stages some signs of hemorrhage might be observed. For example around the tips of the ears or on the stomach. And you might observe diarrhea including some bloody diarrhea. And eventually death occurs within sort of 10 to 15 days usually. The disease spreads mainly by direct contact between infected animals and also by contact with infectious materials. So infected pigs have very high levels of virus in blood and in secretions including urine, feces and oral nasal secretions. So pigs in direct contact become infected quite readily. The virus is very stable in the environment and in infected meat. So in direct contact with either ingestion of pork or by movement of infected vehicles or other materials can also be a route for infecting pigs. So measures for control rely on rapid diagnosis and then the implementation of quarantine and movement restrictions. So there's no vaccine. So there's not the possibility of using vaccination to control disease spread. The pigs that we use mostly come from a high animal health status farm. Most of the experiments we carry out are vaccination experiments where we want to compare different types of vaccines. Generally our experiments would each have 18 pigs in three groups for example and we introduce a control group of nonimmune pigs before challenge with the virulent virus. So we probably have around 21 pigs per experiment and we may do four or five experiments per year. So we're using between 80 and 100 pigs per year. So as much as possible we use preliminary tests in cell culture. For example one approach we use to develop vaccines is to delete genes from the virus genome to try and produce a virus that's attenuated. That is it doesn't cause disease but can induce an effective immune response that protects pigs against challenge. But currently there's not really any effective method to test a vaccine in vitro so we have to use animals to test safety and efficacy of vaccines. So the classic approaches that we're used to produce vaccines that have been effective against other viruses haven't worked for African swine fever. So we currently have two approaches to produce vaccines. One is to try and improve the safety of live attenuated vaccines by manipulating the genome in different ways and trying to understand more about the immune response and what leads to protection and what leads to chronic disease for example. And then another approach is to try and identify which of the many proteins that are coded for by African swine fever virus can induce protection. We first have to identify which of the 165 proteins might induce protection and to do this we've used immune cells from protected pigs and screened those against a library of short peptide sequences containing sequences from the virus to identify which are recognised by the immune lymphocytes. And then we've taken the genes for those proteins and cloned them into safe virus vectors that don't replicate in the pig. So these are vectors that are widely used for vaccine production and are known to have a safe profile. And we're currently carrying out experiments where we immunise pigs with pools of these virus vectors each expressing different African swine fever virus proteins and then measure the immune responses and try and determine which might induce a protection against challenge. Ultimately we have to test vaccines in animals because there's no really effective correlation between what happens in vitro and what you observe in animals.