由于“健康犬能携带并传播狂犬病毒”的认识普遍存在，不少被犬所伤者长期处在极度恐惧中。中国疾病预防控制中心(CDC)传染病预防控制所与美国CDC、贵州省CDC、美国佐治亚大学等单位联合研究得出的结论，否定了“健康犬能传播狂犬病毒”之说。该研究报告近日发表在《传病媒介与动物传染病》（Vector-Borne and Zoonotic Diseases）杂志上。

    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。

    张永振告诉记者，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。

    张永振说，过去10年我国有研究者在外观健康犬的脑组织中检测或分离到狂犬病毒，这些犬可能处在感染后的潜伏期。因此，在被犬类动物所伤后需要及时到犬伤门诊进行暴露后的正确预防处理。但人若暴露10天后，攻击犬仍健康无异常现象，则可以相信人感染狂犬病毒的几率几乎为零。

原始出处：

Vector-Borne and Zoonotic Diseases，8(3): 313-320，Yong-Zhen Zhang，Charles E. Rupprecht

Investigation of the Role of Healthy Dogs as Potential Carriers of Rabies Virus

Yong-Zhen Zhang, Zhen F. Fu, Ding-Ming Wang, Jing-Zhu Zhou, Zhao-Xiao Wang, Tai-Fu Lv, Cheng-Long Xiong, Yang Zou, Wen-Rong Yao, Ming-Hui Li, Guan-Mu Dong, Ge-Lin Xu, Michael Niezgoda, Ivan V. Kuzmin, Charles E. Rupprecht

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.