Clinical signs of caprine arthritis-encephalitis and disease-related pathomorphological changes

Over the past ten years, the small ruminant population in the Russian Federation grew sharply, especially goat population in backyards and on small-scale farms. Alongside with the population growth, clinical signs of some sporadic diseases or diseases that had not been previously registered were detected in animals. Caprine arthritis-encephalitis (CAE) is one of such diseases. It is a chronic infectious disease caused by a small ruminant lentivirus (SRLV) of the Retroviridae family, which includes four genotypes, of which genotypes A (maedi-visna – MVV virus) and B (caprine arthritis-encephalitis virus – CAEV) are of epizootic significance. The disease is characterized by long asymptomatic viral transmission and is associated with progressive lesions in the respiratory organs, joints and udder. The disease also affects nervous system in kid goats aged between 2 and 3 months. Clinical signs of caprine arthritis-encephalitis are not pathognomonic; therefore, it is often misdiagnosed, thus, resulting in a barrier to effective treatment. Given the fact, the issue of antemortem and postmortem diagnosis of caprine arthritis-encephalitis is still urgent, because most veterinary specialists have never encountered this disease and the data available in the literature often do not fully cover all clinical details and pathomorphological features. Therefore, the purpose of the work is to study CAE clinical signs and pathomorphological changes. The article describes in detail clinical manifestation of this disease, postmortem lesions in organs and tissues of the sick animals. The results obtained suggest that the destructive changes in the exposed organs are irreversible and, consequently, there is no effective treatment.

1. Ramírez H., Reina R., Amorena B., de Andrés D., Martínez H. A. Small ruminant lentiviruses: genetic variability, tropism and diagnosis. Viruses. 2013; 5 (4): 1175–1207. DOI: 10.3390/v5041175.

2. Moroz A., Czopowicz M., Sobczak-Filipiak M., Dolka I., Rzewuska M., Kizerwetter-Świda M., et al. The prevalence of histopathological features of pneumonia in goats with symptomatic caprine arthritis-encephalitis. Pathogens. 2022; 11 (6):629. DOI: 10.3390/pathogens11060629.

3. Banks  K.  L., Adams  D.  S., McGuire T.  C., Carlson  J. Experimental infection of sheep by caprine arthritis-encephalitis virus and goats by progressive pneumonia virus. Am. J. Vet. Res. 1983; 44 (12): 2307–2311. PMID: 6318613.

4. Pasick J. Maedi-visna virus and caprine arthritis-encephalitis virus: distinct species or quasispecies and its implications for laboratory diagnosis. Can. J. Vet. Res. 1998; 62 (4): 241–244. PMID: 9798087.

5. Shah C., Böni J., Huder J. B., Vogt H. R., Mühlherr J., Zanoni R., et al. Phylogenetic analysis and reclassification of caprine and ovine lentiviruses based on 104 new isolates: evidence for regular sheep-to-goat transmission and worldwide propagation through livestock trade. Virology. 2004; 319 (1): 12–26. DOI: 10.1016/j.virol.2003.09.047.

6. Pisoni G., Quasso A., Moroni P. Phylogenetic analysis of small-ruminant lentivirus subtype B1 in mixed flocks: evidence for natural transmission from goats to sheep. Virology. 2005; 339 (2): 147–152. DOI: 10.1016/j.virol.2005.06.013.

7. Pisoni G., Bertoni G., Puricelli M., Maccalli M., Moroni P. Demonstration of coinfection with and recombination by caprine arthritis-encephalitis virus and maedi-visna virus in naturally infected goats. J. Virol. 2007; 81 (10): 4948–4955. DOI: 10.1128/JVI.00126-07.

8. Leroux C., Cruz J. C., Mornex J. F. SRLVs: a genetic continuum of lentiviral species in sheep and goats with cumulative evidence of cross species transmission. Curr. HIV Res. 2010; 8 (1): 94–100. DOI: 10.2174/157016210790416415.

9. Preziuso S., Taccini E., Rossi G., Renzoni G., Braca G. Experimental maedi visna virus infection in sheep: a morphological, immunohistochemical and PCR study after three years of infection. Eur. J. Histochem. 2003; 47 (4): 373–378. PMID: 14706934.

10. Smith M. C., Sherman D. M. Goat Medicine. 2nd ed. Hoboken: Wiley-Blackwell; 2009; 348–359.

11. Kaba J., Czopowicz M., Ganter M., Nowicki M., Witkowski L., Nowicka D., Szaluś-Jordanow O. Risk factors associated with seropositivity to small ruminant lentiviruses in goat herds. Res. Vet. Sci. 2013; 94 (2): 225–227. DOI: 10.1016/j.rvsc.2012.09.018.

12. Penkova I. N., Balybina N. Yu., Koptev V. Yu. Detection of animals seropositive for arthritis-encephalitis in goats in the Siberian and Ural Federal districts. Veterinariya. 2022; (3): 34–38. DOI:  10.30896/0042-4846.2022.25.3.34-37. (in Russ.)

13. Kojouri G. A., Emami M., Momtaz H. The first molecular detection of caprine arthritis encephalitis virus (CAEV) in Iran. J. Veterinar. Sci. Technol. 2014; 5 (3): 1000184. DOI: 10.4172/2157-7579.1000184.

14. Jarczak J., Kaba  J., Bagnicka  E. The validation of housekeeping genes as a reference in quantitative real time PCR analysis: application in the milk somatic cells and frozen whole blood of goats infected with caprine arthritis encephalitis virus. Gene. 2014; 549 (2): 280–285. DOI: 10.1016/j.gene.2014.07.063.

15. De Andrés D., Klein D., Watt N. J., Berriatua E., Torsteinsdottir S., Blacklaws B. A., Harkiss G. D. Diagnostic tests for small ruminant lentiviruses. Vet. Microbiol. 2005; 107 (1–2): 49–62. DOI: 10.1016/j.vetmic.2005.01.012.

16. Rowe J. D., East N. E. Risk factors for transmission and methods for control of caprine arthritis-encephalitis virus infection. Vet. Clin. North. Am. Food Anim. Pract. 1997; 13 (1): 35–53. DOI: 10.1016/s0749-0720(15)30363-7.

17. Kudryashov A. A., Balabanova V. I., Babina S. Yu. Pathomorphological findings in lungs and brain at caprine arthritis-encephalitis. Actual Questions of Veterinary Biology. 2014; (3): 54–58. EDN: SPCQYJ. (in Russ.)

18. Kaba  J., Bagnicka  E., Czopowicz  M., Nowicki  M., Witkowski  L., Szalus-Jordanow O. Long-term study on the spread of caprine arthritis-encephalitis in a goat herd. Cent. Eur. J. Immunol. 2011; 36 (3): 170–173.

19. Kaba  J., Czopowicz  M., Nowicki  M., Nowicka  D., Witkowski  L., Szaluś-Jordanow  O. Role caprine arthritis encephalitis virus (CAEV) infection in the occurrence of particular clinical symptoms in adult goats. Bulletin USAMV. Serie Veterinary Medicine. 2012; 69 (1–2). DOI: 10.15835/buasvmcn-vm:69:1-2:8849.

20. Caprine arthritis-encephalitis. In: Slow infections of animals. N. I. Arhipov, I. A. Bakulov, L. I. Sokovyh. Moscow: Agropromizdat; 1987; 79–82. (in Russ.)

21. Jones T. C., Hunt R. D., King N. W. Veterinary pathology. 6th ed. Baltimore, Md.: Williams & Wilkins; 1997. 1392 p

22. Jubb K., Kennedy P., Palmer N. Pathology of domestic animals. Ed. by M. Maxie. Vol. 1–3. 5th ed. Edinburgh; New York: Elsevier Saunders; 2007. 932 р.

23. Koudryashov A. A. Pathoanatomical opening of corpses of animals. Part 1. Conditions of opening; the order of opening of corpses of different animals. Veterinarnaya praktika. 2004; (4): 27–31. EDN: YZUOJO. (in Russ.)