title: Foot-and-mouth disease virus carrier status in Bos grunniens yaks.
abstract: BACKGROUND
  The 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.
  
  
  RESULTS
  All 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.
  
  
  CONCLUSIONS
  After 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.
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology, National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China. changhuiyun@126.com
authors.forename: Huiyun
authors.initials: H
authors.lastname: Chang
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Ma
authors.forename: Tong
authors.initials: T
authors.lastname: Lin
authors.forename: Guozheng
authors.initials: G
authors.lastname: Cong
authors.forename: Junzheng
authors.initials: J
authors.lastname: Du
authors.forename: Jinling
authors.initials: J
authors.lastname: Ma
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology; D002353:Carrier State / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology / Q000821:virology*; D005536:Foot-and-Mouth Disease / Q000276:immunology / Q000821:virology*; D029544:Foot-and-Mouth Disease Virus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D000914:Antibodies, Viral