Isolation and Phylogenetic Analysis of Feline Calicivirus in Siberia

Abstract

The results of the study of the distribution of calicivirus infection in a population of domestic cats of different breeds, contained individually or the group method, the virus isolation in the cell culture and a comparative phylogenetic analysis of their nucleotide sequences with published sequences of reference field and vaccine strains of Feline calicivirus (FCV) from other countries: USA, Germany, Japan, China and Korea are presented. Clinical signs of infection were found in 14.3% of the animals examined. After several passages in the primary kidney cells of the kitten embryo, seven cytopathogenic isolates FCV were isolated: 1 - from a cat with an acute infection, 5 - subclinical infection, 1 - systemic infection. They were adapted to continuous FK-81 cells in which they reached a maximum infectious activity of 10.0 ± 1.15 lg TCD 50 / cm3. Based on the sequence analysis of the open reading frame 2 region of the viral genome Eshli strain showed a close relationship with strain KM016908 from China with the identity of the nucleotide sequences between them of 81.0%. The results of the investigations showed that FCV isolates obtained from animals on the territory of Siberia are genetically different from strains included to imported vaccines used to prevent disease in Russian Federation and also among themselves. This causes a decrease in the effectiveness of preventive measures. In nurseries that do not have contacts and connections between themselves but located in the same geographic region FCV populations may have some genetic differences. A close relationship of some field isolates with strains from other countries geographically located so far from the Siberian region has been revealed. Studies on the molecular epizootology of caliciviruses are important in the development of test systems and the monitoring of the spread of strains in Russia.

Distribution and genetic diversity of Feline calicivirus in Moscow metropolitan area

“…According to the data, the FCV epizootic situation in the Moscow metropolitan area remains stably tense because the infection has been detected in 25% of animals annually. Glotova et al [ 22 ] reported a similar situation in Siberia in 2018. This can be associated with the application of vaccines, developed on a strain basis isolated in the 1960s, and poor awareness of pet owners about this infection.…”

“…The genetic variability of FCV leads to the “obsolescence” of vaccines based on the F9 and F255 strains [ 21 22 23 ]. Seal reported a connection between the phylogenetic relationships and serum neutralization by analyzing 32 nucleotide sequences of the ORF2 region (regions B, C, D, E, and F) of FCV isolates.…”

“…Outbreaks of this disease were recorded in Siberia. A study of 1,125 samples from cats in the Tomsk, Omsk, and Novosibirsk regions detected the FCV genome by polymerase chain reaction in 161 animals (14.3%) [ 22 ]. The FCV belongs to the family Caliciviridae, genus Vesivirus [ 1 ].…”