Advanced Strategies for Developing Vaccines and Diagnostic Tools for African Swine Fever

Abstract

African swine fever (ASF) is one of the most lethal infectious diseases affecting domestic pigs and wild boars of all ages. Over a span of 100 years, ASF has continued to spread over continents and adversely affects the global pig industry. To date, no vaccine or treatment has been approved. The complex genome structure and diverse variants facilitate the immune evasion of the ASF virus (ASFV). Recently, advanced technologies have been used to design various potential vaccine candidates and effective diagnostic tools. This review updates vaccine platforms that are currently being used worldwide, with a focus on genetically modified live attenuated vaccines, including an understanding of their potential efficacy and limitations of safety and stability. Furthermore, advanced ASFV detection technologies are presented that discuss and incorporate the challenges that remain to be addressed for conventional detection methods. We also highlight a nano-bio-based system that enhances sensitivity and specificity. A combination of prophylactic vaccines and point-of-care diagnostics can help effectively control the spread of ASFV.

Pathogenicity and virulence of African swine fever virus

“…The hemadsorption [ 269 ] test has been a basic ASFV diagnostic technique for many decades [ 270 , 271 ]. It is considered a definitive diagnostic test for ASFV detection, but it requires specialized laboratories, primary cell preparation, and takes more than a week to obtain the results, which are normally used in reference laboratories [ 272 ]. Moreover, some ASFV isolates are non-hemadsorbing due to deletion of the EP402R gene, which encodes for the CD2v protein responsible for hemadsorption [ 161 ].…”

“…For these reasons, molecular tests for the detection of ASFV nucleic acid, with high sensitivity and specificity, are the most employed worldwide and are recommended by the WOAH [ 273–275 ]. Generally, these molecular methods target a highly conserved region of the ASFV genome that encodes for the capsid protein p72 ( B646L gene ) [ 272 ]. Real-time PCR is widely considered the gold standard for the detection of ASFV nucleic acid in diagnostic samples, but isothermal amplification techniques have gained popularity owing to the swift method and the lack of thermal amplification [ 276 , 277 ].…”

“…New isothermal amplification methods including loop-mediated (LAMP), rolling circle (RCA), and recombinase polymerase (RPA) have been recently described and used for ASFV detection [ 278–282 ]. CRISPR-associated proteins, engineered via gene-editing techniques are promising next-generation tools for the diagnosis of infectious diseases, including ASF [ 161 , 272 , 283 ].…”

African Swine Fever Virus I267L Is a Hemorrhage-Related Gene Based on Transcriptome Analysis

“…Though it is mild in wild boars in this area, domestic pigs [ 3 ] and wild boars in other areas can have symptoms of a high fever and acute hemorrhages; they die in several days, with a mortality rate of up to 100% [ 4 , 5 ]. Up to now, no commercial vaccine has been approved, except in Vietnam [ 6 ].…”