两株高致病性猪繁殖与呼吸综合征病毒与猪霍乱沙门氏菌的分离及人工共感染猪的致病性试验

Isolation of two highly pathogenic PRRSV coinfected with Salmonella cholersuis and experimental reproduction of the disease in pigs

为研究猪繁殖与呼吸综合征病毒(PRRSV)与细菌混合感染的情况,本研究采用RT-PCR方法对不同猪场采集的样品进行PRRSV检测,并进一步对PRRSV阳性样品进行细菌培养分离,经BIOLOG细菌鉴定仪鉴定,分离培养的细菌为猪霍乱沙门氏菌(S.cholersuis)。利用分离获得的2株PRRSV和一株S.cholersuis进行动物回归试验,结果表明所有人工感染猪在感染后的第5 d出现病毒血症;2份PRRSV分离株单独人工感染的发病率均为100%,死亡率分别为55.6%和100%;PRRSV与S.cholersuis共感染的动物死亡率均为100%。与单独的PRRSV感染组相比,PRRSV与S.cholersuis共感染后实验动物的发病和死亡时间大大缩短,进一步表明其混合感染具有协同致病性,导致发病率和死亡率的上升。

To investigate the mixed infection of porcine reproductive and respiratory syndrome virus （PRRSV） and bacteria, samples collected from different swine farms were detected by RT-PCR and then further to isolate bacteria from PRRSV positive samples. The resulte showed that a Salmonella cholersuis was isolated and identifiecd through BIOLOG bacteria idetification device. Reproduction of the disease showed that all pigs developed viremia at 5 days post artificial infection of either PRRSV isolates, resulting in a morbidity of 100% and the mortality of 55.6% and 100%, respectively. However, the mortality of the pigs was 100% when coinfected by either PRRSV isolates with the S.cholersuis. Furthermore, the clinical signs and death of pigs coinfected with both PRRSV and S.cholersuis were significant early compared with PRRSV infection, which indicated that mixed infection had synergistic effect of pathogenicity, resulting in the higher morbidity and mortality rates.