Many diseases that are commonly known to be transmitted among people, such as measles and (formerly) smallpox, evolved from microbes living in wildlife. Pandemics of Animal Origin: A Growing Threatįor millennia, humans have been stricken, sometimes seriously so, by pathogens originating in animals. But new strategies for dealing with these threats offer the possibility that such diseases need not be a threat and a scourge, and that humans once again can learn to live in balance with the natural ecology that supports us. Despite the extensive public health response to these emerging infectious diseases, the focus has been on reactive rather than preventive efforts. The emergence of such “zoonoses,” responsible for a growing number of disease outbreaks that have sickened or killed millions, is facilitated by the human disruption of natural ecological conditions, which has allowed for increased human-animal contact. 3Įbola and Marburg viruses are just two examples of an emerging but largely overlooked trend: the spread of infectious disease from animals to humans. While the source of this particular outbreak was not known, past human cases of Marburg originated from contact with certain species of cave-dwelling bats that serve as the natural carriers of the virus. The infected patient experienced symptoms including fever, abdominal pain, vomiting, and diarrhea and ultimately died a few weeks into the illness, caused by the Marburg virus. 2Īround the same time that the Ebola outbreak was spreading through West Africa, a human case of a different disease, caused by another pathogen in the same family of viruses, emerged in Uganda. Studies suggest that Ebola is causing severe declines in great ape populations-particularly critically endangered wild lowland gorillas-making it as much a threat to biodiversity as it is to human health. Researchers have detected Ebola infection and mortality in wild chimpanzees, gorillas, and duiker antelopes, and evidence from human outbreaks suggests that these species have served as brief hosts for potential human infection when hunted or handled. Certain bat species are the suspected natural source for the virus and are thought to harbor it without signs of disease.
Prior Ebola outbreaks in humans, as well as a concurrent outbreak in the Democratic Republic of the Congo beginning in August 2014, have been linked to the hunting or handling of wild animals, with subsequent transmission among humans. 1ĭespite global attention and response, 12 months into the outbreak the initial source of human infection still had not been identified. Air travel helped the disease leap from West Africa to other continents, including North America and Europe. Within a year’s time, the outbreak, which was not officially noticed by health authorities until March 2014, had led to approximately 18,000 known human cases and 6,300 deaths, posing an unprecedented challenge to global public health. December 2013, an outbreak of the deadly Ebola virus began in a small village in southern Guinea, the first outbreak of the Zaire Ebola strain in West Africa.
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