Abstract
BackgroundThe carrier status of foot-and-mouth disease virus (FMDV) is complicated, and the role of carrier animals in virus transmission is controversial. To investigate the carrier status of FMDV in animals that live in high altitude, Bos grunniens yaks were infected experimentally with FMDV O/Akesu/58.ResultsAll of the yaks showed clinical signs of foot-and-mouth disease (FMD). Total antibody levels against FMDV measured by liquid-phase blocking enzyme-linked immunosorbent assay (LPB-ELISA) and antibody levels against nonstructural proteins (NSP) showed dynamic changes. Three of the five yaks were indentified as carrier animals by RT-PCR method, and the OP fluids from carrier yaks can cause cytopathic effect (CPE) on BHK-21 cells. At last, five persistent infection strains were isolated. Nucleotide mutations of VP1 gene were analyzed.ConclusionsAfter infected with FMDV, all of the yaks showed typical clinical signs. Yaks can keep carrier status for at least 8 months. Total antibody levels against FMDV measured by LPB-ELISA and antibody levels against NSP were at high level for carrier yaks. Sequence alignment of the five isolated strains showed obvious gene and protein mutations.
Highlights
The carrier status of foot-and-mouth disease virus (FMDV) is complicated, and the role of carrier animals in virus transmission is controversial
As is the lack of error correction mechanism during RNA replication, FMDV has a very high mutation rate ranging from 10-3 to 10-5 per nucleotide site per genome replication, which results in the presence of seven serotypes, multiple subtypes, and variants [5,6]
Yaks came to recovery period
Summary
The carrier status of foot-and-mouth disease virus (FMDV) is complicated, and the role of carrier animals in virus transmission is controversial. Foot-and-mouth disease virus (FMDV), the first demonstrated filterable agent causing animal disease, is belong to the Aphtovirus genus of the Picornaviridae family, and contains a single-stranded positive-sense RNA genome of about 8500 nucleotides [4]. The friendly environment was shown as: small one day temperature difference, high oxygen concentration, and proper atmospheric pressure. Phenotype was influenced by gene and environment, so animals in high altitude regions showed different abilities to oxygen concentration and temperature change. Other abilities showed different, such as the immune response [22,23] This may result in different evolution pressure on pathogens invading animals
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