今天是联合国第七个“世界野生动植物日”，今年全球的主题是“维护地球所有生命”。 2013年12月20日，联合国大会第68届会议宣布每年的3月3日为“世界野生动植物日”，以呼吁人们提升保护野生动植物及其多样性的意识。 Illustration for the 2020 World Wildlife Day campaign under the theme "Sustaining all life on Earth." Credit: World Wildlife Day/Patrick George. 在新冠肺炎疫情暴发、社会对滥食野生动物反映强烈的当下，野生动物保护的问题尤其引人注目。 当今人类新发传染病或流行病70%都与野生动物有关。人类不断食用野味、侵占野生动物的栖息地，野生动物携带的病毒传播给人类的几率越来越大。 今天，我们就来说说流行病与野生动物的“渊源”。 ↓↓↓ 新冠肺炎 （COVID-19）2月29日发布的《中国-世界卫生组织新型冠状病毒肺炎（COVID-19）联合考察报告》指出，新冠病毒是一种动物源性病毒，在武汉发现的早期病例被认为是通过动物传染到人的途径感染。蝙蝠似乎是该病毒的宿主，但中间宿主尚未查明。此前有研究认为，穿山甲为新型冠状病毒的潜在中间宿主。 Facts on COVID-19. /CGTN Graphic by Liu Shaozhen 中东呼吸综合征 （MERS） 此次新冠病毒将冠状病毒再次推向了风口浪尖。曾经致命的SARS病毒和MERS病毒都属于冠状病毒家族，其中MERS病毒的致死率最高，达到34.3%。2012年以来，MERS疫情已经蔓延到27个国家，其中近80%的病例在沙特阿拉伯。中东、非洲和南亚部分地区的单峰驼很快成为MERS病毒的疑似宿主，因为研究人员在骆驼血清中发现了MERS抗体，表明骆驼曾接触过这种病毒。 Two dromedary camels. /VCG2013年11月，一位拥有9头单峰骆驼的43岁男子感染了MERS病毒。在他出现症状之前，他的4头骆驼已经病了。后来，在他和骆驼身上检测到的MERS病毒基因特征相同，这进一步证明单峰驼是该病毒的潜在宿主。此外，2015年在卡塔尔进行的一项研究表明，羊驼也是该病毒的一个潜在宿主。确切的传播途径尚不清楚，蝙蝠是MERS病毒的可能源头。Facts on MERS. /CGTN Graphic by Liu Shaozhen The dromedary camels in the Middle East, Africa and parts of South Asia soon became the main suspected reservoir of MERS-CoV as antibodies to MERS-CoV were detected in camel sera, indicating camels have been previously exposed to the virus.In November 2013, a 43-year-old man who owned nine dromedary camels was infected with MERS-CoV. Before he showed symptoms, four of his camels were sick. Later, MERS-CoV viruses detected in him and the dromedary camel were found to be genetically identical, which further supports that dromedary camels are a potential host of the virus. 尼帕 （Nipah virus disease）Two piglets on grassland. /VCG 说到猪和流行病，也许你会想到尼帕病毒。1998年，在马来西亚一个名为Kampung Sungai Nipah的村庄，一家养猪场里的猪和养猪户出现发烧或抽搐的症状，随后确认是尼帕病毒所致。人类发病因素最早是接触病猪，后来传播方式转变为人传人和饮用被果蝠污染的椰枣汁。研究人员认为，猪只是尼帕病毒的中间宿主，果蝠是原生宿主。他们推测，果蝠吃过的水果落入养猪场，猪吃了这些水果后也感染了病毒。养猪场建在果蝠栖息地附近是疫情暴发的主要原因。猪被运往其他地区导致疫情进一步蔓延。Facts on Nipah virus disease. /CGTN Graphic by Liu Shaozhen Scientists speculated that fruits contaminated by bats might drop into pig farms and pigs were infected after eating the fruit. The location of pigsties in the vicinity of fruit bats' habitats is a major cause of the outbreak. The transport of pigs to more areas led to the further spread of the disease.The Nipah virus can remain stable in the date palm sap for over seven days at 22 degrees Celsius. People mostly got infected from drinking the fresh date palm sap or through contact with sick persons. In outbreaks in Bangladesh and India, human-to-human transmission was often reported, which was different from the outbreaks in Malaysia and Singapore where humans were infected through contact with sick pigs. 埃博拉 （Ebola virus disease）Bonobo mature male and juvenile male in Democratic Republic of the Congo. /VCG 埃博拉病毒得名于1976年在埃博拉河附近一个村庄暴发的疫情。人类一旦感染埃博拉病毒，严重时可致体内外出血。接触这些患者的呕吐物、血液或其他体液会使更多人感染。科学家推测，人类感染埃博拉病毒最初是通过直接接触被感染动物（比如大猩猩或黑猩猩）的血液或体液。但猩猩不太可能是埃博拉病毒的天然宿主，研究人员认为，天然宿主可能是果蝠。 Facts on Ebola virus disease. /CGTN Graphic by Liu ShaozhenScientists speculated that the Ebola virus was initially spread to humans through direct contact with the blood or body fluids of infected animals, such as gorillas and chimpanzees.Once people are infected, they normally have a fever, muscle pain and headache in the beginning. As their conditions deteriorate, they would vomit and have diarrhea. Worst of all, they would bleed internally and externally. The touch of these patients' vomis, blood or other body fluids would get more people infected. That's how the Ebola virus spread in humans. 亨德拉 （Hendra virus disease）A horse with its mouth wide open. /VCG 亨德拉病毒感染是造成受感染的马和人严重患病的一种罕见的人畜共患疾病。狐属狐蝠科的果蝠是这一病毒的天然宿主。1994年，澳大利亚布里斯班郊区亨德拉镇的21匹赛马出现了类似流感的呼吸道疾病症状，14匹赛马和1人死亡。蝙蝠将病毒传给马的途径仍然未知，科学家推测赛马可能接触了狐蝠的唾液、尿液或被狐蝠污染的食物而感染。根据悉尼大学2017年的一项研究，亨德拉病毒感染的风险与人类入侵狐蝠栖息地有关。Facts on Ebola virus disease. /CGTN Graphic by Liu ShaozhenIn 1994, 21 stabled racehorses in Hendra, a suburb in Brisbane, Australia, had flu-like symptoms similar to respiratory diseases. Soon, 14 of them died and a new virus named Hendra was isolated from the horse's lung tissue. Two people who had closely taken care of these ill horses, a horse trainer and a groom, were infected. One died with severe pneumonia and the other survived an influenza-like illness.Although the mechanism of bat-to-horse transmission is still a mystery, scientists speculated that horses might be infected from eating food contaminated by urine, saliva or other things from the flying foxes. According to a study made by researchers from the University of Sydney in 2017, the risk of Hendra infection was correlated with human intrusion into habitats of flying foxes. 马尔堡 （Marburg virus disease）Vervet monkeys (Cercopithecus aethiops) are also known as African green monkeys. /VCG 马尔堡病毒又称绿猴病病毒，源自非洲乌干达一带。1967年，西德马尔堡等地几所医学实验室的工作人员中同时暴发了一种严重出血热，他们多是因为接触实验室内染有马尔堡病的非洲绿猴而致病。近年来，马尔堡病毒较大的两次流行发生在刚果民主共和国（ 1998 年至 2000 年），以及安哥拉（2005年），死亡率超过80%。虽然科学家认为是非洲绿猴将这种病毒传播给人类，但它并不是自然宿主，因为猴子一旦感染便很快死亡。自然宿主可与病毒共存，埃及果蝠就是其中之一，但其是否为马尔堡病毒的唯一天然宿主仍然未知。 Facts on Marburg virus disease. /CGTN Graphic by Liu ShaozhenAlthough African green monkeys are considered to bring the virus to humans during the first outbreak, they are not natural hosts of the Marburg virus because they also die quickly once infected. To be the natural hosts, they have to live safely with the virus. Egyptian fruit bats are the ones.In 2007, 40 years after the first outbreak, the common Egyptian fruit bat was detected to be infected, and the Marburg virus was isolated from healthy infected bats caught in Uganda in the same year. Mines or caves inhabited by these fruit bats are the Marburg virus reservoir. However, it remains unknown whether the Egyptian fruit bat is the exclusive natural host for the Marburg virus.