Case fatality

# Case fatality

Discussion

Encyclopedia
In epidemiology
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...

, case fatality (CF) or fatality rate, is the ratio
Ratio
In mathematics, a ratio is a relationship between two numbers of the same kind , usually expressed as "a to b" or a:b, sometimes expressed arithmetically as a dimensionless quotient of the two which explicitly indicates how many times the first number contains the second In mathematics, a ratio is...

of death
Death
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....

s within a designated population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...

of people with a particular condition, over a certain period of time. An example of a fatality rate would be 9 deaths per 10,000 people at risk per year. This means that within a given year, out of 10,000 people formally diagnosed with a disease, 9 died.

The rate for the Spanish flu was >2.5%, about 0.1% for the Asian and Hong Kong flus, and <0.1% for other influenza pandemics.

Zaïre Ebola Virus is among the deadliest viruses with a case fatality rate of roughly 90%.
Rabies
Rabies
Rabies is a viral disease that causes acute encephalitis in warm-blooded animals. It is zoonotic , most commonly by a bite from an infected animal. For a human, rabies is almost invariably fatal if post-exposure prophylaxis is not administered prior to the onset of severe symptoms...

, if contracted by an unvaccinated individual who does not seek prophylactic treatment, is also an extremely deadly virus, with a case fatality rate approaching 100%.