RESUMO
Classical swine fever virus (CSFV) is an ancient pathogen that continues to pose a threat to animal agriculture worldwide. The virus belongs to the genus Pestivirus and the family Flaviviridae. It causes a multisystemic disease that affects only pigs and is responsible for significant economic losses. CSFV infection is probably a multistep process that involves the proteins in the virus envelope and more than one receptor in the membrane of permissive cells. To date, the cellular receptors essential for CSFV entry and their detailed functions during this process remains unknown. All the viral envelope proteins Erns, E1 and E2 are involved in the entry process to some extent and the experimental approaches conducted until now have helped to unveil their contributions. This review aims to provide an overview of current knowledge on cellular molecules described to be involved in CSFV entry, including complement regulatory protein 46 (CD46), heparan sulphate (HS), Laminin receptor, Integrin ß3, Annexin II, MERKT and ADAM17. This knowledge would not only help to understand the molecular mechanisms involved in pestivirus infection, but also provide a rational basis for the development of nonvaccinal alternatives for CSFV control.
Assuntos
Vírus da Febre Suína Clássica , Peste Suína Clássica , Doenças dos Suínos , Animais , Suínos , Vírus da Febre Suína Clássica/fisiologia , Linhagem Celular , Proteínas do Envelope Viral , Receptores de Superfície Celular/metabolismoRESUMO
Nucleotide and codon usage are typically examined to investigate viral evolution. In this study, we analyzed the genetic information of 46 strains of classical swine fever virus (CSFV) RNA, nucleotide usage in the internal ribosome entry site (IRES), the nucleotide context surrounding the initiation codon, and synonymous codon usage in the translation initiation region. Phylogenetic analysis of the IRES element indicated that the genetic diversity of this element is generally similar to the phylogenetic clusters of CSFV genotypes. Nucleotides surrounding the initiation codon of CSFV RNA were generally more stable (ACAUGGCACAUGGAGUUG) compared to the internal AUG in the CSFV coding sequence. The second codon position after the initiation codon was generally selected to be GAG, which has lower tRNA abundance in pigs than its synonymous member (GAA). Regarding the synonymous codon usage bias in the CSFV translation initiation region, some codons showing low tRNA abundance in pigs are more frequently located in the translation initiation region than in the open reading frame of CSFV. Although CSFV, similarly to other RNA viruses, has a high mutation rate in nature, the regulatory features of nucleotide and synonymous codon usage of the IRES element, the nucleotide context surrounding the initiation codon and the translation initiation region in CSFV RNA have been 'branded' in the system of translation initiation to accommodate gene expression mediated by the cap-independent translation mechanism.
Assuntos
Vírus da Febre Suína Clássica/classificação , Vírus da Febre Suína Clássica/genética , RNA Viral/genética , Sequências Reguladoras de Ácido Ribonucleico , Animais , Vírus da Febre Suína Clássica/fisiologia , Códon de Iniciação , Evolução Molecular , Variação Genética , Filogenia , Biossíntese de Proteínas , RNA de Transferência/genética , Análise de Sequência de RNARESUMO
Experiments were done to determine if transporting live screwworms Cochliomyia hominivorax Coquerel (Diptera: Calliphoridae) for developing new strains from countries where foot-and-mouth disease and classical swine fever are endemic, to the mass rearing facilities in Mexico and Panama, may introduce these exotic diseases into these countries. Are screwworms capable of harboring and spreading foot-and-mouth disease virus (FMDV) and classical swine fever virus (CSFV) when they are grown in virus-inoculated larval rearing medium? In one experiment, screwworm larvae were reared in a FMDV-inoculated artificial medium containing either 0.1 % formaldehyde or antibiotics as an antimicrobial agent. In another experiment, larvae were similarly reared in a CSFV-inoculated artificial medium containing 0.1% formaldehyde. In each experiment, samples of larvae and the rearing media were collected daily until pupation occurred. The presence of FMDV was assayed by observing cytopathic effects on cell cultures and a conventional reverse transcription-polymerase chain reaction (RT-PCR); CSFV was assayed using an avidin-biotin complex assay and a conventional RT-PCR. For media containing antibiotics, FMDV was detected in a larval sample collected on day 1 and in media samples on days 1, 2 and 3. No FMDV was detected from larval and media samples collected on all other days. For media containing formaldehyde, FMDV and CSFV were not detectable in larval or media samples collected on all sampling days. These results indicate that FMDV and CSFV cannot survive in rearing medium containing formaldehyde as an antimicrobial agent. Therefore, insects collected in endemic regions and reared using formaldehyde-containing medium for at least one generation at the collection site should be free of FMDV and CSFV and can be transported safely to a strain development/mass rearing facility.
Assuntos
Vírus da Febre Suína Clássica/fisiologia , Dípteros/crescimento & desenvolvimento , Dípteros/virologia , Vírus da Febre Aftosa/fisiologia , Animais , Meios de Cultura , Larva/virologia , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Prostaglandins (Pgs) have been shown to inhibit the replication of several DNA and RNA viruses. Here we report the effect of prostaglandin (PgA1) on the multiplication of a positive strand RNA virus, Classical Swine Fever Virus (CSFV) in PK15 cells. PgA1 was found to inhibit the multiplication of CSFV. At a concentration of 5 micrograms/ml, which was nontoxic to the cells, PgA1 inhibitis virus production in 99%. In PgA1 treated cells the size and number of characteristic Classical Swine Fever focus decreased in amount.