A study outlined in the “Proceeding of the Royal Society: Biology” has shed new light on the factors that go into an outbreak in Ebola. While scientists have long suggested that bats are the most likely carriers of Ebola and have surmised how Ebola outbreaks can start, this paper offers one of the most comprehensive efforts yet to detail the initial spread of the disease.
Unsurprisingly, bats aren’t the only party to blame and human-caused events are at least partially to blame. Deforestation, hunting, and the continued spread of human development are also factors in causing Ebola outbreaks.
Bats Are Great Hosts For Ebola
Bats have long been suspected as the primary carrier of the Ebola virus. Bats, and other animals that play host to diseases, are called reservoir animals. They act as the staging ground for certain diseases, allowing them to multiply in low levels and when the opportunity arises, to hop over into human hosts where they can wreak havoc.
Often, viruses that are deadly to humans reside in other animals were they carry out their own peaceful existence. Ebola is not believe to harm bats under normal circumstances, but once the virus infects a human it spreads through human cells so quickly that the body is overwhelmed.
The reason as to why bats are such great hosts is still up for debate, but the study found that bats carry genes that allow them to be disproportionately good at detecting and repairing damaged DNA. It has been suggested that this allows them to repair the damage caused by viruses, which often target DNA specifically, much more quickly than other animals.
Bats are also known to be almost tumor free. Tumors generally grow due to damaged DNA, but bats appear to be able to repair said DNA before the tumor grows out of control. So what does all of this mean? It’s possible that deadly bats are able to handle powerful diseases, such as Ebola, and to keep them in check.
Once the Ebola hops into a different species, however, such as humans, the immune system of the new host animal is quickly overwhelmed.
Human Activity Exposes Us To Bat-Borne Diseases
While bats may indeed be the carriers of deadly diseases, they certainly aren’t seeking us out, attempting to spread the disease. Bats generally avoid people, and are active mostly at night. Some bats, such as the so-called “vampire bats” do occasionally feed on humans, but in general bats stay away from human settlements.
With the continued spread of humans into forested areas, and the destruction of natural habitats, bats are increasingly coming into contact with people. In some regions of Africa and other parts of the world, bats are also hunted for their meat, increasing the risk of bat-borne diseases crossing over and infecting humans.
Add in the increased ability of people to travel, and the risk of diseases spreading has increased greatly. It’s believe that a small boy in Guniea named Emile Ouamouno was the patient zero for Ebola. While scientists are not yet sure how he contracted the disease, Emile lived in a remote rain forest village and is believed to have come into contact with a bat. Emile and most of his family succumbed to the disease.
In the not so distant past, Ebola would have likely burned through the village, killed most of the people, and died out. The disease would simply be too deadly to spread too far. Now, with advanced means of travel and a long incubation period, the disease can literally hop continents.
Ebola quickly spread through Western Africa along trade and travel routes. Sick patients have also boarded planes and ended up in Europe and the United States, though so far only a few cases have been reported outside of Africa. From start to finish, however, ebola has been added by human activity.