The persistence of foot-and-mouth disease virus on wool

SUMMARY Five Suffolk sheep, held in a high-security isolation room, were exposed for 2 hours to the aerosol of 3 mature pigs that had been infected with foot-and-mouth disease virus (FMDV), strain O₁-BFS. The fleeces of 3 of the sheep were contaminated with FMDV at 2 days post exposure (dpe), while at 5 dpe the fleeces of all 5 sheep were more extensively, and more heavily, contaminated. The persistence of FMDV on contaminated wool was examined in vitro using multiple 0.5 g samples of Merino wool that were each contaminated with one of 3 strains of FMDV in tissue-culture medium: O₁-BFS, O-Morocco (O-MOR 9/91) or an Asia 1 strain (TAI 1/90). Wool samples were held at either 4°C, 18°C or 37°C, and decay curves were established for each virus at each temperature. These curves predicted that O₁-BFS, O-MOR 9/91 and TAI 1/90 would fall below detect-able levels at 72, 70 and 48 days post contamination (pc), respectively, for wool stored at 4°C; at 11, 12 and 12 days pc, respectively, for wool stored at 18°C; and at 57, 68 and 33 hours pc, respectively, for wool stored at 37°C. For wool contaminated with O₁-BFS-infected sheep faeces, urine or blood, or with O₁-BFS-infected cattle saliva, decay curves predicted virus to persist for 5 to 11 days pc at 18°C. We demonstrated that the simulated scouring of FMDV-contaminated wool at 60° to 70°C would usually reduce virus to below detectable levels. The detergent component of the scouring process had little, if any, antiviral activity, and scouring at 20°C or 50°C had limited impact on FMDV titres . We recommend that either (1) simple storage of FMDV-contaminated wool for 4 weeks at temperatures of 18°C or higher, or (2) scouring of contaminated wool at 60° to 70°C would be sufficient to remove the threat of FMDV-contaminated wool being infectious to other animals .     

Outbreak investigations and genetic characterization of foot-and-mouth disease virus in Ethiopia in 2008/2009

The study was conducted in three regional states of Ethiopia: Amhara, Oromia, and Addis Ababa from August 2008 to April 2009 with the objectives of identifying the genetic diversity of serotypes and topotypes in Ethiopia, and determining the attack rate and associations of potential risk factors with foot-and-mouth disease (FMD) seropositivity. A total of 496 cattle were clinically and serologically examined for presence of specific lesions and nonstructural protein for FMD, respectively. Of which, 140 (28.2%) manifested clinical signs and lesions suggestive of FMD, and 219 (44.2%) were seropositive. From a total of 7,781 animals observed and recorded on a designed format in six districts, 1,409 (19.6%) were infected, and 15 (0.12%) died during outbreaks of FMD. Epidemiological investigations revealed that the morbidity rate of the disease was 21.1% in Akaki-kality sub-city, but the mortality rate was <2% in all districts. Furthermore, the mortality and case fatality rates were relatively higher, 1.6% and 8.9% in calves than the other age groups, respectively. From a total of 33 bovine epithelial tissue-cultured samples, 19 (57.6%) showed CPE for FMD virus, in which 16 samples had serotype O and EA-3 topotype, while three samples had found serotype A, Africa topotype, and G-VII strain. Various strains of FMD viruses were isolated in Ethiopia in this study, and therefore, further detailed studies on the evaluation of available vaccines and the development of a vaccine which contains cocktails of antigens of FMD virus strains in the country should be encouraged.     

反向遗传学技术可快捷改善口蹄疫疫苗株的酸稳定性

口蹄疫(FMD)是由口蹄疫病毒(FMDV)引起猪、牛、羊等多种偶蹄动物感染的一种急性、热性、高度接触性传染病,被OIE列为必报疫病之首,我国将其规定为一类动物传染病。目前,疫苗接种与扑杀结合的综合措施是防治和根除FMD的最经济有效的技术手段。FMDV病毒没有囊膜包裹,对物理化学物质的刺激非常敏感。     

口蹄疫病毒感染机理的研究进展

介绍了口蹄疫病毒感染过程中的吸附、穿透和脱壳步骤。综述了病毒mRNA的翻译机理以及病毒转录和基因复制的机理。简要描述了病毒粒子的成熟过程，包括病毒RNA正链的装配以及VP0裂解成VP4和VP2的过程。     

口蹄疫病毒致病机理研究进展

利用经典的生物化学和物理分析手段来研究感染口蹄疫病毒(FMDV)的细胞能揭示FMDV各个蛋白的结构和功能,而通过对FMDV遗传差异的研究可知病毒蛋白的正确结构在病毒的复制和致病中起着重要作用。近年,利用基因工程的方法研究人员可直接验证FMDVRNA结构、编码区和多聚蛋白在FMDV复制和致病的相关推测。     

Microarray-based detection and typing of foot-and-mouth disease virus

Foot-and-mouth disease virus (FMDV) is the most economically important veterinary pathogen because of its highly infectious nature and the devastating effects the virus has on the livestock industry. Rapid diagnostic methods are needed for detection and typing of FMDV serotypes and differentiation from other viruses causing vesicular diseases. We developed a microarray-based test that uses a FMD DNA chip containing 155 oligonucleotide probes, 35-45 base pair (bp) long, virus-common and serotype-specific, designed from the VP3-VP1-2A region of the genome. A set of two forward primers and one reverse primer were also designed to allow amplification of approximately 1100 bp of target sequences from this region. The amplified target was labelled with Alexa-Fluor 546 dye and applied to the FMD DNA chip. A total of 23 different FMDV strains representing all seven serotypes were detected and typed by the FMD DNA chip. Microarray technology offers a unique capability to identify multiple pathogens in a single chip.