6 Things You Might Not Know About Ebola
There's been a new outbreak of Ebola in the Democratic Republic of the Congo. Eleven people have been sickened by the disease, and one has died. Here are some things you might not have known about Ebola.
1. THERE'S MORE THAN ONE KIND OF EBOLAVIRUS.
Five species of Ebolavirus have been identified, each named after the place they sprung up: Ebola (formerly Zaire), Bundibugyo, Sudan, Taï Forest, and Reston. All but one—Reston—arose in Africa. The Reston subtype is named after a town in Virginia where an outbreak occurred in 1989, followed by incidents in Texas and Pennsylvania; all three were tied to infected monkeys exported by a single facility in the Philippines. All Ebolavirus species affect people and nonhuman primates—monkeys, gorillas, and chimpanzees—but Reston doesn't cause detectable disease in humans.
2. EBOLA HIJACKS THE IMMUNE SYSTEM.
Researchers are finding out just how clever Ebola is. One key to its lethal success is the stealth way it shuts down immune system defenses, the same way an air force will disable air defenses before sending in the bombers. Ebola obstructs parts of an immune system that are activated by molecules called interferons. These interferons have a vital role in fighting Ebola, usually with scorched-earth tactics such as apoptosis, or cell self-destruction. A 2014 study found that Ebola disables signals the cells use to defend against its attack using a protein called VP24, which binds to a specific protein that takes signaling molecules in and out a cell's nucleus. Blocked from communication, the cell can't call for help or get the order to self-destruct. The virus then hijacks the cell, uses it to make more viruses, and spreads them to more cells. It also produces ebolavirus glycoprotein, which binds to cells inside blood vessels, increasing their permeability and leading to leakage. This contributes to the catastrophic bleeding characteristic of late-stage Ebola infection.
3. BATS ARE THOUGHT TO BE THE KEY HOSTS OF EBOLA.
Scientists believe that Ebola's natural host species, or "reservoir hosts," are bats. Infected bats can pass the virus to other mammals, including rats, primates, and us. No one is sure how people first became exposed to Ebola, but the best guess is that monkeys were the conduit. Local hunters in Africa likely became infected while butchering the animals. Anyone who became sick likely infected their family and, if hospitalized in an unsanitary facility, other patients. When the illness spreads from person to person, it does so through direct contact with the bodily fluids of someone who is sick with or has died from Ebola.
4. MEDICAL DETECTIVE WORK IS THE ONLY WAY TO STOP AN EBOLA OUTBREAK.
It takes the investigative skill of a homicide detective to stop an outbreak. Professionals call it contact tracing. Here's how it works: Ebola victim A is isolated and interviewed. Anyone who had close contact with A is put into quarantine for 21 days. If they exhibit no symptoms, they're free to go when the three weeks are up. If they come down with Ebola, they become victim B, and another contact trace begins. If the investigators miss anyone, the outbreak will continue.
5. HAVING MALARIA AND EBOLA AT THE SAME TIME MAY HELP PEOPLE SURVIVE.
Researchers analyzing the the 2014 outbreak of Ebola in West Africa made a surprising finding: patients who had an active malaria parasite infection were actually more likely to survive the Ebola virus, and by a significant degree. While just over half (52 percent) of Ebola patients not infected with malaria survived, those co-infected with malaria had a survival rate of 72 to 83 percent, depending on their ages and the amount of Ebola virus in their blood. The researchers aren't yet sure why, but the prevailing theory is that malaria somehow modifies the immune response to Ebola by toning down a phenomenon called the "cytokine storm"—the body's own response to an Ebola infection, which inadvertently kills the host while attempting to eliminate the pathogen. If malaria can dampen this response, infected patients may have a better chance of surviving.
6. IF YOU'RE A SCIENTIST, YOU CAN ORDER EBOLA ONLINE.
We do not yet have a vaccine or antiviral drug to treat Ebola, but many scientists are working to find one. One source is the National Institute of Allergy and Infectious Diseases (NIAID)'s BEI Resources, which gives research facilities access to microbiological materials called reagents that can help them develop diagnostics and vaccines for emerging diseases, including Ebola. Scientists must be registered with BEI to request materials. Reagents are not active viruses, so they can't spread; on the biosafety level, or BSL, scale—which ranks the severity of infectious disease and sets required safety protocols for working with them in a lab—the Ebola-related reagents are considered BLS 1—the lowest risk. (Live Ebola virus is BLS 4—the highest.) Ordering is limited to one Ebola-related reagent at a time, and can be ordered only twice per year.