Key result
African swine fever variant IV infection links to lower viral loads but more chronic lesions.
Why the study?
Data on pathology from field infections of African swine fever were scarce in domestic pigs and unavailable in wild boar, despite emerging German virus variants.
Observational
Yes
Natural infection with ASF variant IV in wild boars may lead to a more protracted, less acute course of the disease, highlighting the need to monitor virulence differences among variants.
May indicate variant-specific ASF chronicity in wild boar; leaves open implications for surveillance and control strategies.
In 2020, African swine fever (ASF) was first identified in German wild boar, reaching a case number of about 4400 to date. Upon experimental infection, pathology is well documented; however, data on field infections are scarce in domestic pigs and not available from wild boar, respectively. Although the ASF viral genome is considered exceptionally stable, a total of five lineages with 10 distinct virus variants of genotype II have emerged in Eastern Germany. To investigate the pathology in naturally infected wild boar and to evaluate virus variants II, III and IV for their virulence, wild boar carcasses were obtained from three different outbreak areas. The carcasses underwent virological and pathomorphological investigation. The animals revealed characteristic ASF lesions of the highest severity accompanied by bacterial infections in several cases. In particular, wild boar infected with variant IV from Spree-Neiße (SN) district showed lower viral genome loads and total viral antigen scores, but simultaneously tended to reveal more chronic lesions. Our findings indicate a protracted course of the disease at least after infection with variant IV, but need confirmation under standardized experimental conditions. There is a strong need to monitor differences in the virulence among variants to identify potential attenuation that might complicate diagnosis. In addition, veterinarians, hunters and farmers need to be made aware of less acute courses of ASF to consider this as an important differential to chronic classical swine fever.
No takes yet. Share an insight, caveat, or question.
Sehl‐Ewert et al. (2022) conducted an observational in African swine fever. African swine fever virus variants II, III, and IV was evaluated on Virological and pathomorphological characteristics. Natural infection with African swine fever variant IV in wild boar resulted in lower viral genome loads and antigen scores but more chronic lesions, indicating a protracted disease course.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: