Researchers from CReSA have demonstrated that protecting pigs against African Swine Fever is not science fiction.

These are the conclusions of a study recently published in the journal PLoS One. African Swine Fever Virus (ASFV) is in continuous expansion since its last entrance in Europe through Georgia in 2007.

African Swine Fever (ASF) is a disease of domestic pigs caused by African Swine Fever Virus (ASFV). The fact that the disease is endemic in Sardinia and overall, in many Sub-Saharan African countries, where it causes important losses, provoked the reentering of the virus in Europe trough Republic of Georgia in 2007. Since then, the virus has continued its expansion through adjacent countries, including Russia, where the situation remains uncontrolled nowadays.

The lack of available vaccines against ASFV complicates the control of the disease even more. Therefore, developing an efficient and safe vaccine against ASF is a must.

The last results obtained by the research group from CReSA clearly demonstrate the possibility of protecting pigs against a lethal ASFV challenge by using DNA vaccines encoding 3 of the viral antigens (ASFV encodes more than 150 different proteins). Moreover, the relevance of the CD8+ T-cells (a lymphocyte subset capable of recognising infected cells and specifically destroy them) in protection, has been definitively confirmed.

Dr. Fernando Rodríguez, principal investigator of this research line explains the results obtained: “Our initial work was based on preliminary studies performed in the mid nineties demonstrating the immunogenic properties of three ASFV proteins: p54, p30 and hemagglutinin (HA). In our study, we have been able to demonstrate that DNA vaccines (in the form of innocuous DNA plasmid molecules) encoding these three viral antigens, are capable of provoking a significant delay of the death of the animals after ASFV lethal challenge and more importantly, that 33% of the immunised pigs survive and totally recovered from the infection. To achieve this protection, optimising the presentation of the vaccine encoded antigens to the specific CD8+ T-cells by ubiquitination (a label that marks proteins for intracellular degradation), was mandatory. In fact, the protection conferred totally correlated with the presence of large number of specific CD8+ T-cells in the blood of surviving pigs with no need of antibodies-help.

This research group is currently in the process of characterising new viral antigens (within the rest of the ASFV 150 proteins) with potential to provoke protective CD8+ T-cell responses. “The final objective of our work is finding an optimal vaccine formulation capable to protect the haplotype-diversity found in our conventional pig farms. It will not be an easy task but certainly we believe that it could be feasible,” Dr. Rodriguez says.

The results of this study have been recently published in: Argilaguet JM, Pérez-Martín E, Nofrarías M, Gallardo C, Accensi F, Lacasta A, Mora M, Ballester M, Galindo-Cardiel I, López-Soria S, Escribano JM, Reche PA, Rodríguez F. DNA Vaccination Partially Protects against African Swine Fever Virus Lethal Challenge in the Absence of Antibodies. PLoS One. 2012;7(9):e40942. doi: 10.1371/journal.pone.0040942.

Dr. Fernando Rodríguez González: Researcher of the CReSA. Principal investigator of the research line “Pathogenesis and profilaxis of Asfavirus infections" - Email: fernando.rodriguez@cresa.uab.cat

UK research project to control poultry red mite

LAYERSHEALTH1010
Infestation of hen houses with the poultry red mite is a major health concern of the European poultry industry with significant economical losses. The mites live, off-host, in inaccessible areas of the cages during daylight and emerge during darkness to feed on the hens, biting through the skin to feed on blood. Infestation with these mites has important animal welfare implications including anaemia, feather-pecking and an increased incidence of cannibalism, thus having a significant impact on productivity.

The BBSRC has recently awarded a £0.55M research grant to Moredun scientists in collaboration with Pfizer Animal Health to develop a vaccine to help protect hens against these blood sucking mites.

Dr Alasdair Nisbet who is heading the project at Moredun commented, "Controlling mite populations is now a major problem, with most pesticides affording only limited or short-lived reduction in the population of mites. There is also the issue of development of drug resistance and environmental contamination which means there is an urgent need to develop alternative control strategies".

The team's approach is to determine whether it might be possible to vaccinate laying hens using specific extracts of the mites thus inducing an immune response in the hens that will attack and kill the mites when they take a blood meal from an immunised hen.

"Our goal is to identify the bits of the mite that will induce the best immune responses in the hens and produce large quantities of these using recombinant technologies to enable large scale vaccination trials to take place. Preliminary work at Moredun has shown that a vaccination approach is a feasible option to control red poultry mite and we are really excited about progressing this work," Nisbet concluded.

Professor Douglas Kell, BBSRC Chief Executive, said "Diseases in farmed animas are a serious animal welfare and food security issue. This new project looking at red mites in poultry highlight the vital role of bioscience research in ensuring farmed animals have the best possible welfare standards, as well as reducing the significant economic losses caused by reduced productivity."