The Role of Antibody Detection in African Swine Fever Surveillance and Disease Monitoring

African swine fever (ASF) surveillance relies on timely and accurate diagnosis to detect infection, monitor disease spread, and support effective control measures. While molecular assays remain the primary approach for detecting the virus during active infection, antibody detection provides valuable complementary information that can strengthen surveillance programmes. This becomes particularly important in situations where assessing previous exposure or identifying infected animals using pathogen detection alone may be challenging. 

For practicing veterinarians involved in herd health monitoring, outbreak investigations, and surveillance programmes, understanding when antibody detection can add diagnostic value is essential for making informed testing decisions. 

Why Antibody Detection Matters 

Following ASFV infection, pigs develop antibodies against several structural and non-structural viral proteins, including p72, p54, p30, pK205R, and pB602L. As these antibodies appear at different stages of infection, antibody detection provides additional insight into the animal's infection status and complements direct virus detection¹. 

Antibody detection becomes increasingly relevant with the emergence of attenuated ASFV strains. Because these strains may exhibit intermittent viremia, relying solely on pathogen detection could reduce the likelihood of identifying infected animals. Combining antibody detection with pathogen detection can therefore strengthen surveillance and improve the overall assessment of herd infection status². 

ELISA: The Foundation of ASF Antibody Detection 

Enzyme-linked immunosorbent assay (ELISA) remains the most widely used laboratory method for detecting ASFV antibodies. Different ELISA formats have been developed to improve diagnostic performance for specific surveillance objectives. 

Common ELISA formats include: 

• Indirect ELISA: Developed using recombinant proteins such as CD2v, p30, pB602L, pp62, pK205R, I329L, p11.5, and p22, enabling antibody detection across different stages of infection. Some assays also support differentiation of wild-type viruses from CD2v gene-deleted strains^1,3,4,5,6.

• Blocking (Competitive) ELISA: Provides high sensitivity for detecting antibodies in complex antigen mixtures and has been developed using proteins including p72, p54, p30, and pK205R¹.

• Double-Antigen Sandwich ELISA: Uses p30 and p72 proteins to support laboratory-based antibody detection and surveillance^7,8.

These ELISA platforms continue to play an important role in surveillance programmes because they can process large numbers of samples while providing reliable antibody detection. 

Expanding Options for Field Surveillance 

Advances in diagnostic technology have broadened the options available beyond conventional ELISA. 

Rapid immunochromatographic assays enable visual antibody detection within a short time and are well suited for field applications where immediate screening is beneficial. Other emerging platforms, including chemiluminescent immunoassays (CLIA), fluorescent microsphere assays, quantum dot-based assays, luciferase immunoprecipitation systems, recombinant protein-coated microbeads, and nanoplasmonic biosensors—continue to enhance antibody detection capabilities while expanding laboratory and point-of-care testing options¹. 

Sample selection is another important consideration during surveillance. Although serum remains the conventional sample for antibody testing, oral fluid has demonstrated comparable performance using recombinant p30 protein. This provides veterinarians with a less invasive sampling option that may simplify herd-level surveillance while reducing animal handling¹. 

Antibody Detection Methods at a Glance¹ 

Key Takeaway 

Antibody detection is an important component of African swine fever surveillance because it complements pathogen detection and provides additional information on herd infection status. ELISA remains the cornerstone of laboratory antibody testing, while rapid immunochromatographic assays and newer biosensor-based platforms continue to expand surveillance options. Selecting the appropriate antibody detection method and sample type according to the surveillance objective can help veterinarians strengthen disease monitoring and support more informed herd health decisions. 

References

1. Hu Z, Tian X, Lai R, Wang X, Li X. Current detection methods of African swine fever virus. Frontiers in Veterinary Science. 2023 Dec 8;10:1289676. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2023.1289676/full 

2. Kosowska A, Cadenas-Fernández E, Barroso S, Sánchez-Vizcaíno JM, Barasona JA. Distinct African swine fever virus shedding in wild boar infected with virulent and attenuated isolates. Vaccines. 2020 Dec 16;8(4):767. https://www.mdpi.com/2076-393X/8/4/767 

3. Lv C, Zhao Y, Jiang L, Zhao L, Wu C, Hui X, Hu X, Shao Z, Xia X, Sun X, Zhang Q. Development of a dual ELISA for the detection of CD2v-unexpressed lower-virulence mutational ASFV. Life. 2021 Nov 10;11(11):1214. https://www.mdpi.com/2075-1729/11/11/1214 

4. Yang Y, Xia Q, Sun Q, Zhang Y, Li Y, Ma X, Guan Z, Zhang J, Li Z, Liu K, Li B. Detection of African swine fever virus antibodies in serum using a pB602L protein-based indirect ELISA. Frontiers in Veterinary Science. 2022 Sep 23;9:971841. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.971841/pdf 

5. Zhong K, Zhu M, Yuan Q, Deng Z, Feng S, Liu D, Yuan X. Development of an indirect ELISA to detect African swine fever virus pp62 protein-specific antibodies. Frontiers in Veterinary Science. 2022 Jan 13;8:798559. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2021.798559/full 

6. Li L, Qiao S, Liu J, Zhou Y, Tong W, Dong S, Liu C, Jiang Y, Guo Z, Zheng H, Zhao R. A highly efficient indirect ELISA and monoclonal antibody established against African swine fever virus pK205R. Frontiers in Immunology. 2023 Jan 9;13:1103166. https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.1103166/pdf 

7. Wang M, Song J, Sun J, Du Y, Qin X, Xia L, Wu Y, Zhang G. Development of an effective double antigen sandwich ELISA based on p30 protein to detect antibodies against African swine fever virus. Viruses. 2022 Sep 30;14(10):2170. https://www.mdpi.com/1999-4915/14/10/2170 

8. Wang L, Li D, Liu Y, Zhang L, Peng G, Xu Z, Jia H, Song C. Development of an effective one-step double-antigen sandwich ELISA based on p72 to detect antibodies against African swine fever virus. Frontiers in Veterinary Science. 2023 Jun 9;10:1160583. https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2023.1160583/pdf