中美科学家颠覆狂犬病传播理念

    犬能传播狂犬病是普通大众都了解的一个常识，对民众而言，只要是有狂犬病的犬无论其有无发病，都被认为可以传播狂犬病。因此，只要被犬咬，受伤者都会处于惊慌状态，一些专家也告知，尽早注射狂犬病疫苗，甚至有些谨慎的民众就算没咬破皮都会去注射疫苗。

 

    近期，中国CDC联合贵州省CDC、美国CDC、美国佐治亚大学等机构对狂犬病的传播进行研究，得出最新结论颠覆了人们对狂犬病的常规认识。他们的研究否定了健康犬传播狂犬病之说。最新的成果公布在《Vector-Borne and Zoonotic Diseases》上。

 

领衔此项研究的张永振研究员介绍，该研究的现场选在狂犬病高发的贵州省安龙县。该县2004年狂犬病发病率曾高达10/10万以上，疫点周围犬群中狂犬病毒流行率较高。2005年，研究人员在安龙县的狂犬病疫点周围采集从未接受兽用狂犬病疫苗免疫的153只犬的唾液，用酶联免疫吸附试验(ELISA)试剂盒检测，对其中的15只可疑犬隔离观察6个月。观察期间每10天采集可疑犬的唾液。研究者发现，这些犬在6个月的观察期中没有出现狂犬病临床症状。实验室内采用免疫组化及逆转录聚合酶链反应(RT-PCR)方法检测其唾液、脑组织，以及其他器官组织，也没有发现狂犬病毒抗原或病毒RNA，仅有2只犬的血液抗狂犬病毒中和抗体阳性。该结果表明，健康犬不传播狂犬病毒。

 

  2004年世界卫生组织发布的狂犬病专家咨询会技术报告称：“伤人的犬或猫在暴露发生后至少10天保持健康，可以终止人暴露后的预防处理措施。”国外有研究也表明，犬在出现狂犬病临床症状前3天的唾液中可以检测到狂犬病毒；75%的犬患狂犬病后仅存活4天，所有的狂犬病犬在出现临床症状的10天内死亡。

 

原文检索：Investigation of the Role of Healthy Dogs as Potential Carriers of Rabies Virus

【Abstract】

 To investigate whether healthy animals are potential carriers of rabies virus in China, 153 domestic dogs were collected from a rabies enzootic area, Anlong county in Guizhou Province, and monitored for 6 months. Initially, findings of rabies virus antigen in the saliva of 15 dogs by an enzyme-linked immunosorbent assay (ELISA) test suggested they might be carriers. These 15 dogs were kept under observation for 6 months. None of the dogs showed any clinical signs of rabies during the observation period. Moreover, using the ELISA test alone, detection of rabies virus antigen in saliva of some animals was not consistent during the observation period. However, none of the saliva samples collected either at the time of acquisition or during the observation period was found to be positive for rabies virus RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). Furthermore, neither viral antigen nor viral RNA was detected in the brain samples collected at the time of euthanasia. These results do not provide support for the contention that healthy dogs act as carriers in rabies. Caution is urged when preliminary and nondefinitive tests, such as ELISA, are used to infer clinical status related to rabies.