In short
African swine fever is an important viral disease in domestic pigs and wild boars with up to 100% mortality. No vaccines are available so far to contain the disease.
The macrophages constitute the first line of defence of the immune system. Face to the ASF virus, they become ineffective and allow the virus to replicate and invade the host organism.
Project description
Due to its relevance for animal health and the pig industry, African swine fever (ASF) is one of the most important viral diseases in domestic pigs. The causative agent, African Swine Fever Virus (ASFV), induces usually asymptomatic diseases in the African wild Suidae (warthog, bush pigs, …). In contrast, infection of domestic pigs and European wild boars results in a wide range of clinical pictures, varying from subclinical disease to severe haemorrhagic disease with up to 100% mortality depending on the virulence of the isolate.
The current epidemic occurring since September 2018 in wildlife in Belgium is caused by a highly virulent ASFV strain of genotype II closely related to the Georgian strain isolated in 2007. Several
genotypes exist but the most studied ones are the genotypes I and II. The genotype I has been introduced in Europe in the 60ies and eradicated in the next decades, except in Sardinia.
The occurrence of ASF in wild boars in Europe is of particular concern because there is no vaccine available and containment and eradication measures are hardly applicable to wild boar populations, constituting a continuous threat to the domestic pig production. Subunit and inactivated vaccines are not effective. Attenuated vaccines are more promising but there is still safety and efficacy problems and production constraints.
In this project, we study the tropism of ASFV for subpopulations of macrophages present in different tissues in order to determine the impact on the horizontal and vertical transmission and virulence/pathogenicity. Next, the receptors involved in the ASFV entry in macrophages will be determined. We use those findings to produce and titrate wild type virus and to attenuate wild type strains by repeated passages on non-porcine cell lines expressing the receptors as a proof-of-concept vaccine development. In an animal experiment, the cytokine expression and the activation of immune cells will be compared between strains of different virulence in order to obtain a better understanding of the in vivo viral evasion mechanism from the innate immune response.
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