Which Contagious Diseases Are The Deadliest?
No one knows what the death toll in the Ebola epidemic will be. As of Tuesday, nearly 2,500 people have died and nearly 5,000 have caught the virus, the World Health Organization says.
So how does this epidemic compare with the toll taken by other contagious diseases?
Comparing fatality rates could help put the current Ebola outbreak in perspective. Trouble is, getting an accurate value for many diseases can be hard, especially in places where the health care infrastructure is weak.
Take the situation in West Africa right now. “We can only count those who come to the doctor, not those who stayed home and got well, or those who stayed home and died,” says Carol Sulis, an epidemiologist at Boston University School of Medicine and the Boston Medical Center.
Another issue is that “deadliest” can mean two things. It can refer to the fatality rate — the number of deaths per number of cases — or it can mean the number of deaths in total caused by a disease.
What’s more, diseases can take a different toll in different parts of the world. In low- and middle-income countries, only limited medical care may be available, if that. This will raise the fatality rate for many infectious diseases, such as tuberculosis, malaria and infectious diarrhea.
"Similar to Ebola, people’s chances of survival increase for most of these [contagious] diseases, some dramatically, if people receive medical treatment," says epidemiologist Derek Cummings, at the Johns Hopkins Bloomberg School of Public Health.
Even if lists have their limitations, they can shed light. We spoke to Cummings and Sulis and consulted data from the World Health Organization and the U.S. Centers for Disease Control and Prevention to come up with two lists: the deadliest contagious diseases by death toll and by death rate if untreated.
See the lists here.
Photo: Do you know what the deadliest disease is? Hint: It’s not Ebola (viral particles seen here in a digitally colorized microscopic image, at top right, along with similar depictions of other contagious diseases) NPR Composite/CDC