野生鸟类传染性疾病研究进展

由于具有独特的飞行能力和极强的地理扩散能力,鸟类活动为某些传染性疾病的快速传播和扩散带来了潜在风险.自20世纪以来,以禽霍乱、禽波特淋菌病、西尼罗河热、禽流感等为代表的鸟类疾病频繁暴发,导致为数众多的野生鸟类、家禽甚至人类死亡,给社会造成巨大的经济损失.因此,有关鸟类传染性疾病的研究已引起了国内外学者的广泛关注.从鸟类传染性疾病的生态学特征、疾病对鸟类与人类社会的影响、鸟类对疾病的传播、鸟类疾病的监测、预警和防控等方面对野生鸟类的传染性疾病研究进展进行了综述.不同疾病导致的鸟类死亡量、易感物种数量、暴发频率和地理扩散等特征差异显著.20世纪以来,疾病已成为全球生物多样性的七大威胁因子之一.疾病可能造成鸟类大量死亡,从而对鸟类种群,特别是濒危鸟类种群造成严重影响.其中,人畜共患病还会导致家禽家畜甚至人类的死亡,从而对社会产生严重的影响.野生鸟类作为多种疾病传播的媒介,其移动和迁徙可能会导致疾病的传播与扩散.开展全面的监测活动和建立疾病预警体系,对于疾病的防控具有重要意义.

Review of research progress of infectious diseases in wild birds

Due to their flight ability and strong geographic dispersal, birds play important roles in the transmission and dissemination of infectous diseases. Since last century, a variety of infectious diseases such as avian cholera, avian tuberculosis, West Nile fever, avian influenza, and so on, have emerged and reemerged, and consequently have resulted in the death of numerous wild birds and poultry and as well as humans, and caused huge economic loss and serious social impact that have raised considerable concern. In this paper, the ecological character of infectious diseases and their impact on wild birds and humans, transmission of bird diseases, surveillance, early warning, prevention, and control of bird diseases, status and prospect of wildlife diseases surveillance, and prevention and control in China are reviewed. Bird diseases can be caused by an array of bacteria, viruses, fungi, parasites, and other pathogens. Different diseases are highly variable in the magnitude of losses, species affected, frequency of recurrence, and geographic spread following initial events. Diseases have been one of the seven biggest threats to global biodiversity since last century. They are causative of physical and physiological dysfunction as well as problems in breeding, behavior, and other aspects that influence the health of birds and reduce their survival ability. Diseases could cause mass death of individuals, resulting in serious impact on bird populations, especially those of endangered species. Some diseases may also impact on habitat selection and geographic distribution of birds. Moreover, birds are also involved in the dissemination of zoonoses that could infect livestock and humans, and affected birds may even be employed in biowarfare and bioterrorism deliberately. Because wild birds act as vectors for various diseases, their movement plays important roles in transmission of diseases. For example, wild birds are the natural vectors for low pathogenic avian influenza. Through direct contact or shedding dropping into soil, water, food, or other taints affected birds could transmit the virus to other birds and poultry periodically, and result in quick geographic dispersal of avian influenza. Birds can also make migrations carrying a variety of pathogens; bird migrations are closely related with outbreaks of many infectious diseases. Therefore the establishment of full-scale surveillance and early warning systems are of great importance for prevention and control of bird diseases. Passive surveillance is aimed at investigation of morbidity and mortality events and monitoring of sentinel species; active surveillance is aimed at early detection of diseases through sampling and testing of animal and environment. Based on these surveillance data, the OIE standard for risk assessment is a widely used method for risk analysis of animal diseases. The State Forestry Administration of China has established an epidemic diseases surveillance network since 2004; 717 cases of animal diseases involving 36,538 individuals have been detected as of 2008, including the HPAI outbreak of wild birds at Qinghai Lake in 2005. However, we advocate establishment of more surveillance stations in Qinghai-Tibet area, development of related regulations and rules, enhancement of scientific support to the surveillance activities, and improvement of the capacities of local surveillance stations.