J Vet Sci.  2024 Jul;25(4):e45. 10.4142/jvs.23261.

Brain invasion of bovine coronavirus: Virology molecular analysis of bovine coronavirus infection in calves with severe pneumonia and neurological signs

• Yilmaz SG
• Aydin O
• Tali HE
• Karadag G
• Sonmez K
• Bayraktar E
• Yilmaz A
• Turan N
• Mutlu Z
• Iqbal M
• Richt JA
• Yilmaz H

• KMID: 2558449
• DOI: http://doi.org/10.4142/jvs.23261

Abstract

Importance
Although the role of bovine coronavirus (BCoV) in calf diarrhea and respiratory disorders is well documented, its contribution to neurological diseases is unclear.
Objective
This study conducted virological investigations of calves showing diarrhea and respiratory and neurological signs.
Methods
An outbreak of diarrhea, respiratory, and neurological disorders occurred among the 12 calves in July 2022 in Istanbul, Türkiye. Two of these calves exhibited neurological signs and died a few days after the appearance of symptoms. One of these calves was necropsied and analyzed using molecular and histopathological tests.
Results
BCoV RNA was detected in the brain, lung, spleen, liver, and intestine of the calf that had neurological signs by real-time reverse transcription polymerase chain reaction. Immunostaining was also observed in the intestine and brain. A 622 bp S1 gene product was noted on gel electrophoresis only in the brain. Phylogenetic analysis indicated that the BCoV detected in this study had a high proximity to the BCoV strain GIb with 99.19% nucleotide sequence homology to the strains detected in Poland, Israel, Türkiye, and France. No distinct genetic lineages were observed when the brain isolate was compared with the respiratory and enteric strains reported to GenBank. In addition, the highest identity (98,72%) was obtained with the HECV 4408 and L07748 strains of human coronaviruses.
Conclusions and Relevance
The strain detected in a calf brain belongs to the GIb-European lineage and shares high sequence homology with BCoV strains detected in Europe and Israel. In addition, the similarity between the human coronaviruses (4408 and L07748) raises questions about the zoonotic potential of the strains detected in this study.

Keyword

Turkey; coronavirus; bovine coronavirus; brain; PCR; phylogeny