How does one decide on whether a disease is truly deadly, or even the deadliest of all diseases? Is it by sheer numbers killed? Or by the odds of being infected? How about the likelihood of survival? Why not all three?

Here are ten deadly diseases you definitely don't want to get.

10: Dengue Fever

Kills: 25,000 Per Year

Dengue Fever is a mosquito-carried tropical disease with no vaccine or treatment, and kills about 25,000 people a year. . It is also one of the fastest growing diseases in the world with the number of recorded outbreaks jumping from 9 to 100 in the last 40 years. Despite this disease having an estimated 2.5 billion people at risk, Dengue is usually not fatal.

9: Leishmaniasis

Kills: 20,000-30,000 Per Year

Like Dengue, Leishmaniasis has no vaccine or cure and is a growing threat with 1.3 million new cases each year. Currently it kills between 20,000 to 30,000 people per year. Unlike Dengue, Leishmaniasis is slightly more widespread as it prospers in conditions usually found among the poorest in the world with most hotspots in Africa, India and Brazil, although it is growing in the Mediterranean areas.

8: African Sleeping Disease

Kills: 300,000 Per Year

African Sleeping Disease  jumps ahead of the diseases behind it due to sheer numbers killed, with around 300,000 people dying  a year. Spread by the Tsetse fly, this disease is fairly rare, as long as you do not live in one of the 36 sub-Saharan countries it exists in. Even then, 80 percent of all new cases come from one country: Democratic Republic of the Congo.

7: Cholera

Kills: 100,000 Per Year

Cholera is a diarrhoeal disease which can kill with amazing rapidity (sometimes within hours). Although it kills far fewer than African Sleeping Disease (about 100,000 a year), Cholera is less discriminant in where it can hit. Spread by tainted water or food, it presents about three to five million cases each year.

6: Malaria

Kills: 650,000-1.2 Million Per Year

Malaria marks a major jump in this list as far as deaths go. Numbers are arguable with some claiming around 650,000 deaths, while a new study shows that this number is closer to 1.2 million.  Malaria is transmitted by mosquitoes and is both treatable and preventable; due to this, the majority of deaths occur in Africa where treatment is either unavailable or unaffordable.

5: Pneumonia

Kills: 1.1 Million Children Per Year

Pneumonia has the undesirable moniker of being the number one killer of children below the age of five (around one million a year).Pneumonia inflames the lungs and is spread by a multitude of viruses. Further, pneumonia can be contracted nearly anywhere; luckily it is treatable and curable, which means that the majority of deaths occur outside of the developed world.

4: Lung Cancer

Kills: 1.6 Million Per Year

The biggest killer cancer of them all, lung cancer accounts for 1.6 million deaths annually. With a low survival rate,  the best thing one could do would be to avoid tobacco smoke at all costs (both first and second-hand smoke) as a study from the United Kingdom pinned 86 percent of all cases on this factor.

3: Tuberculosis

Kills: 1.3 Million Per Year

According to the World health Organization, about one third of people (about 2 billion) currently have Tuberculosis. Of this number, about 1.3 million die annually. TB is an airborne disease meaning that even being near a person infected could result in your own infection. Although it is curable, it requires an expensive six month regimen not feasible in many parts of the world.

2: AIDS

Kills: 1.6 Million Per Year

HIV/AIDS kills 1.6 million people each year and infects 2.3 million new people each year. A total of about 35 million people are currently infected with the disease. Spread by bodily fluids, AIDS has no cure and has killed nearly 36 million people across the globe since it was first documented in 1981.

1: Ischemic Heart Disease

Kills: 7.4 Million Per Year

The number one spot had to go to the by and far largest killer on this list, with roughly 7.4 million people killed in 2012. Caused by high blood pressure, smoking, and obesity, among other factors, Ischemic Heart Disease results in the cutting off of blood to the heart, often resulting in heart attacks. It is the number one killer in western countries and remains a scourge all over the world.