Sel’skokhozyaistvennaya Biologiya [Agricultural Biology], 2016, V. 51, № 4, pp. 459-466.

doi: 10.15389/agrobiology.2016.4.459eng

UDC 636.4:578:612.017.1:577.083

 

LABORATORY DIAGNOSTICS OF CHRONIC AND ASYMPTOMATIC
FORMS OF AFRICAN SWINE FEVER

A.D. Sereda, O.A. Dubrovskaya, A.R. Imatdinov, O.M. Strizhakova,
A.P. Vasil’ev, I.P. Sindryakova, A.V. Lunitsin

All-Russian Institute of Veterinary Virology and Microbiology, Federal Agency of Scientific Organizations, 1, ul. Akademika Bakuleva, pos. Vol’ginskii, Petushinskii Region, Vladimir Province, 601120 Russia, e-mail sereda-56@mail.ru

Received May 17, 2016

 

African swine fever (ASF) caused by African swine fever virus (ASFV) of Asfivirus genus, Asfarviridae family, can occur in peracute, acute, subacute, chronic or asymptomatic form. At early stages of epizootics, the infection usually occurs in its acute form eventually becoming chronic and/or asymptomatic. Seven to ten days post infection the survived pigs develop virus-specific antibodies which persist for a long time. An assumption is reasonable that in the near future, due to repeated passaging ASFV in wild boar populations in European countries, the ASFV isolates may appear which will cause chronic or asymptomatic rather than the acute forms of the disease. In our study we compared different tests to find those the most effective to reveal latent carriers when no apparent symptoms of the disease observed. Thus, our research was aimed at investigation of some special aspects of the laboratory diagnostics of chronic and asymptomatic forms of ASF. The chronic form of the disease was observed in a pig experimentally inoculated with an attenuated ASF virus Stavropol 01/08 A4S2/9k (at passage 33) at a dose of 16.0 HAU50. On day 5 to 7 post inoculation the signs typical of chronic forms of the infection were registered including depression and fever up to 40.5 °С. The antiviral antibody was detected in the swine blood serum from day 7. After the animal was killed on day 21, a haemadsorption assay revealed ASF virus present at low titers in spleen and mandibular lymph node samples while in liver and lung samples it was not found. Based on the results of polymerase chain reaction (PCR), the viral DNA was determined in the mandibular lymph node sample only. Furthermore, immunoblotting assay identified ASF antibody titers of 1:20 to 1:160 in all the organs examined. The asymptomatic forms of ASF were observed in a wild boar yearling which has been intramuscularly inoculated with an attenuated ASF virus strain MK-200 at a dose of 106.0 HAU50. The antiviral antibody was observed in the wild boar serum from day 8. After the animal was killed on day 25, no pathological signs typical of ASF were found, nor was ASF virus found in the organ samples examined using haemadsorption assay or its DNA was detected in PCR. In immunoblotting assay, virus-specific antibodies were identified in liver, spleen, lung and mandibular lymph node samples at dilutions of 1:40 to 1:320. The opportunity of detecting antibodies in spleen, lung and/or liver samples facilitates the monitoring for ASF to be carried out under the infection control campaigns, especially with respect to wild boars shot in game husbandries. Animals sequentially infected with an ASFV low-virulent isolate and a virulent one can survive, in which case it is quite possible to diagnose the disease using both PCR and serological methods. For making laboratory diagnosis of ASF chronic and/or asymptomatic forms, as well as carrying out monitoring studies, serological methods are recommended.

Keywords: African swine fever, chronic and asymptomatic forms of infection, laboratory diagnostics, immunoblotting.

 

Full article (Rus)

Full text (Eng)

 

REFERENCES

  1. Dixon L.K., Costa J.V., Escribano J.M., Rock D.L., Vinuela E., Wilkinson P.J. Family Asfarviridae. M.H.V.V. Regenmortel (ed.). London Academic Press, San Diego, CA, 2000: 159-165.
  2. Sereda A.D., Balyshev V.M. Voprosy virusologii, 2011, 4: 38-42 (in Russ.).  
  3. Makarov V.V., Sukharev O.I., TSvetnova I.V. Veterinarnaya praktika, 2013, 1(60): 6-16 (in Russ.).
  4. Khomenko S., Beltrán-Alcrudo D., Rozstalnyy A., Gogin A., Kolbasov D., Pinto J., Lubroth J., Martin V. African swine fever in the Russian Federation: risk factors for Europe and beyond. EMPRES watch, 2013, 28: 1-14. Available http://www.fao.org/docrep/018/aq240e/aq240e.pdf. No date.
  5. Manual of diagnostic tests and vaccines for terrestrial animals. Chapter 2.8.1. African swine fever. Office International des Epizooties, Paris, France, 2012. 7th ed. Available http://www.oie.int/fileadmin/Home/fr/Health_standards/tahm/2.08.01_ASF.pdf.  No date.
  6. Sanchez-Vizcaino J.M. African swine fever diagnosis. In: African swine fever. Y. Becker (ed.). Martinus Nijhoff, Boston, USA, 1987: 63-71.
  7. Vishnyakov I.F., Mitin N.I., Karpov G.M., Kurinnov V.V., Yashin A.T. Veterinariya, 1991, 4: 28-31 (in Russ.). 
  8. Perez-Filgueira D.M., Gonzalez-Camacho F., Gallardo C., Resino-Talavan P., Blanco E., Gomez-Casado E., Alonso C., Escribano J.M. Optimization and validation of recombinant serological tests for African swine fever diagnosis based on detection of the p30 protein produced in Trichoplusia ni larvae. J. Slin. Microbiol., 2006, 44(9): 114-3121 CrossRef
  9. Reis A.L., Parkhouse R.M.E., Penedos A.R., Martins C., Leitão A. Systematic analysis of longitudinal serological responses of pigs infected experimentally with African swine fever virus. J. Gen. Virol., 2007, 88: 2426-2434 CrossRef
  10. Sereda A.D., Kazakova A.S., Imatdinov A.R., Kolbasov D.V. Humoral and cell immune mechanisms under African swine fever (review). Agricultural Biology, 2015, 50(6): 709-718 (in Engl., in Russ.) CrossRef, CrossRef
  11. Cubillos C., Gumez-Sebastian S., Moreno N., Nunez M.C., Mulumba-Mfumu L.K., Quembode C.J., Heath L., Etter E.M.C., Jori F., Escribano J.M., Blanco E. African swine fever virus serodiagnosis: A general review with a focus on the analyses of African serum samples. Virus Res., 2013, 173: 159-167 CrossRef
  12. Steiger Y., Ackermann M., Mettraux C., Kihm D.U. Rapid and biologically safe diagnosis of African swine fever virus infection by using polymerase chain reaction. J. Clin. Microbiol., 1992, 30(1): 1-8.
  13. Malogolovkin A., Burmakina G., Titov I., Sereda A., Gogin A., Baryshnikova E., Kolbasov D. Comparative analysis of African swine fever virus genotypes and serogroups.  Emerging Infectious Diseases, 2015, 21(2): 312-315 CrossRef
  14. Balyshev V.M., Kalantaenko Yu.F., Bolgova M.V., Prudnikova E.Yu. Doklady Rossiiskoi akademii sel'skokhozyaistvennykh nauk, 2011, 5: 52-53 (in Russ.). 
  15. Kazakova A.S., Sereda A.D., Strizhakova O.M., Zhivoderov S.P., Lyska V.M., Balyshev V.M., Morgunov Yu.P., Shubina N.G., Khukhorova I.Yu., Kolbasov D.V., Gusev A.A. Veterinariya, 2014, 9: 52-56 (in Russ.).   
  16. Afonso C.L., Alcaraz C., Brun A., Sussman M.D., Onisk D.V.,  Escribano J.M.,  Rock D.L. Characterization of p30, a highly antigenic membrane and secreted protein of African swine fever virus. Virology, 1992, 189(1): 368-373 CrossRef
  17. Kolbasov D.V., Balyshev V.M., Sereda A.D. Veterinariya, 2014, 8: 3-8 (in Russ.).     
  18. Balysheva V.I., Prudnikova E.Yu., Gal'nbek T.V., Balyshev V.M. Doklady Rossiiskoi akademii sel'skokhozyaistvennykh nauk, 2015, 1-2: 65-69 (in Russ.).
  19. Ruiz-Gonzalvo F., Carnero M.E., Bruyel V. Immunological responses of pigs to partially attenuated African swine fever virus and their resistance to virulent homologous and heterologous viruses. Proc. CEC/FAO Research Seminar «African Swine Fever», Sardinia, Italy. P.J. Wilkinson (ed.). EUR 8466 EN. Luxemburg, Belgium, Commission of the European Communities, 1981: 206-216.
  20. Vigario I.D., Terrinha A.M., Nunes J.F.M. Antigenic relationships among strains of African swine fever virus. Archiv für die gesamte Virusforschung, 1974, 45(3): 272-277 CrossRef
  21. King K., Chapman D., Argilaguet J.M., Fishbourne E., Hutet E., Cariolet R., Hutchings G., Oura C.A., Netherton C.L., Moffat K., Taylor G.,  Le Potier M.F., Dixon L.K., Takamatsu H.H. Protection of European domestic pigs from virulent African isolates of African swine fever virus by experimental immunization. Vaccine, 2011, 29: 4593-4600 CrossRef
  22. Nepoklonov E.A., Zelentsov V.A., Reutova E.G., Kurinov V.V. Materialy nauchno-teoreticheskoi konferentsii VNIIVViM [Proc. Sci. Conf. Vet. Virology and Microbiology]. Pokrov, 1981: 242-244 (in Russ.).    
  23. Koromyslov E.V. Tezisy nauchnoi konferentsii VNIIVViM [Proc. Sci. Conf. Vet. Virology and Microbiology, Pokrov]. Pokrov, 1984: 244-246 (in Russ.).    
  24. Kotel'nikov A.P., Petrov Yu.I., Zelentsov V.A., Reutova E.G. Materialy nauchno-teoreticheskoi konferentsii VNIIVViM [Proc. Sci. Conf. Vet. Virology and Microbiology]. Pokrov, 1981: 151-152 (in Russ.).     
  25. Petrov Yu.I., Kotel'nikov A.P., Mitin N.I., CHeryatnikov L.L., Tatarintseva N.T. Tezisy nauchnoi konferentsii VNIIVViM [Proc. Sci. Conf. Vet. Virology and Microbiology]. Pokrov, 1985: 24-27 (in Russ.).
  26. Mur L., Gallardo C., Soler A., Zimmermman J., Pelayo V., Nieto R., Sánchez-Vizcaíno J.M., Arias M. Potential use of oral fluid samples for serological diagnosis of African swine fever. Vet. Microbiol., 2013, 165(1-2): 135-139 CrossRef

back