Genetic clustering of recent classical swine fever virus isolates from Karnataka, India revealed the emergence of subtype 2.2 replacing subtype 1.1

Abstract

The phylogenetic analysis of 11 CSFV isolates from Karnataka, India obtained during the year 2012-13 was undertaken to obtain the most reliable genetic typing of the CSFV isolates based on E2, NS5B and 5 0 UTR genomic regions. The study indicated that all the 11 CSFV isolates belonged to subgroup 2.2. The most reliable classification was obtained with sequence data from the NS5B region which separated all the isolates based on the history of outbreak and geographic origin. Analysis of full length E2 amino acid sequences revealed different genetic makeup of Indian 2.2 isolates compared to 2.2 isolates from different countries. The group 2.2 viruses are gradually spreading as confirmed by frequent detection/ isolation of group 2.2 viruses in the recent years and replacing the subgroup 1.1 viruses, which were hitherto predominantly involved in CSF outbreaks in India.Keywords Classical swine fever virus Á Phylogenetic analysis Á E2 Á NS5B and 5 0 UTR

In Vivo Demonstration of the Superior Replication and Infectivity of Genotype 2.1 with Respect to Genotype 3.4 of Classical Swine Fever Virus by Dual Infections

“…The shift in CSFV populations in the field, from genotypes 1 and 3 to genotype 2, was observed worldwide [8][9][10][11][12]. However, the mechanisms responsible for the shift remain unclear.…”

“…Genotype 3 contains most of the strains with restricted distribution [3,[5][6][7]. In recent years, there has been a shift in CSFV genotypes in the field, from genotypes 1 and 3 to genotype 2, which was observed in Europe and Asia [8][9][10][11]. The mechanisms for this shift remain unclear.…”

Meta-analysis of classical swine fever prevalence in pigs in India: A 5-year study

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A Critical Review about Different Vaccines against Classical Swine Fever Virus and Their Repercussions in Endemic Regions

“…Despite the control program, a high prevalence of CSF has been reported in most of the states of the country [ 214 ] with the circulation of several subgenotypes including 1.1, 2.1, and 2.2 across the country. Similar to other CSF-endemic regions discussed in this current work, India is experiencing a switch from the previous dominant subgenotype 1.1 to more recent genotypes such as 2.1 and 2.2 [ 215 , 216 , 217 ]. However, a recent study defined as new subgenotype 2.4 to CSFV strains that circulated in India during 2012–2013 previously located in genotype 2.1 [ 177 ], but so far, the subgenotype 2.2 has been determined as the current dominant [ 217 ].…”