The deadliest disease to ever exist is tuberculosis, which have claimed at least an estimated 1 billion lives over the last 2 centuries.
Malaria, smallpox and the bubonic plague are also some of the deadliest diseases to ever exist.
And in modern times, ischemic heart disease is also the leading non communicable cause of death in the world.
Tuberculosis is caused by mycobacterium tuberculosis, which is an airborne disease remains the world's top infectious killer today, and causes over 1.5 million deaths per year.
Tuberculosis has also killed more people than all the natural disasters and the wars combined.
Malaria, which is also another deadliest disease to ever exist, is transmitted by mosquitoes and is an ancient disease that is estimated to have killed roughly half of all humans who have ever existed.
Rabies and Naegleria fowleri (Primary Amebic meningoencephalitis) are also some of the deadliest diseases and conditions to exist.
The rare disease that has no cure is Hutchinson-Gilford Progeria Syndrome (Progeria), which occurs is a genetic condition that causes premature, rapid aging that begins in early childhood.
People with Hutchinson-Gilford Progeria Syndrome (Progeria), experience hair loss, aged looking skin, joint abnormalities, and severe cardiovascular issues.
Hutchinson-Gilford Progeria Syndrome (Progeria), is managed through use of daily medication like lonafarnib, which can slow the progression of Hutchinson-Gilford Progeria Syndrome (Progeria) and extend lifespans.
Hutchinson-Gilford Progeria Syndrome (Progeria) occurs in 1 in 4 million people.
Other rare diseases that have no cure are Fibrodysplasia Ossificans Progressiva (FOP / "Stoneman Syndrome"), which is a severe genetic disorder in which the body's connective tissues like muscles, tendons and ligaments gradually turn into bone over time, also known as ossification.
This then forms rigid bridges across joints that severely restrict your movement.
Treatments for Fibrodysplasia Ossificans Progressiva (FOP / "Stoneman Syndrome") are strictly focused on preventing trauma to avoid any flareups and managing any chronic pain.
Fibrodysplasia Ossificans Progressiva (FOP / "Stoneman Syndrome") occurs in 1 in 2 million people.
ALS also known as Amyotrophic Lateral Sclerosis is also a rare disease that has no cure and affects around 5,000 Americans a year.
ALS or Amyotrophic Lateral Sclerosis is a progressive and fatal neuromuscular disease that attacks the nerve cells in your brain and your spinal cord and leads to muscle weakness, loss of voluntary control and eventually respiratory failure.
Various medications and therapies are available to help slow the physical decline and maximize comfort in people with ALS, but there's no cure.
Duchenne Muscular Dystrophy or DMD is also another rare disease that affects in 1 3,600 people born and is a severe type of muscular dystrophy, which mainly affects boys and causes rapid, progressive muscle degeneration as a result of lack of the protein called dystrophin, which often leads to the loss of ability to walk by your early teens.
Duchenne Muscular Dystrophy is often managed through use of steroids, physical therapy and cardiac medications to manage the symptoms and support daily function.
And finally, another rare disease and condition is water allergy also known as Aquagenic Urticaria, which is extremely rare and only around 100 cases are reported globally.
Water allergy is a very uncommon condition, in which a person develops painful, itchy hives and welts almost immediately upon exposure to water, which means that even sweating, snow or tears can cause the allergic reactions to water.
The symptoms of water allergies are often managed with phototherapy, antihistamines and a strict avoidance of water contact.
The rarest disease on earth is Field's Disease, which is a neuromuscular disorder that causes muscle degeneration and severely weakens the body.
Field's disease is also officially documented as the world's rarest disease, with only 2 known cases of Field's disease ever recorded which was in twin sisters in the UK.
Another rarest disease and condition on Earth is Ribose-5-Phosphate Isomerase (RPI) Deficiency.
Ribose-5-Phosphate Isomerase (RPI) Deficiency is the rarest disease, and only a single confirmed case of Ribose-5-Phosphate Isomerase (RPI) Deficiency has been diagnosed worldwide since it was first discovered as far back as 1984.
The condition Ribose-5-Phosphate Isomerase (RPI) Deficiency is a genetic metabolic disorder that damages the white matter in your brain, which leads to seizures, psychomotor delays and muscle stiffness.
Only 1 confirmed patient in recorded history was diagnosed with Ribose-5-Phosphate Isomerase (RPI) Deficiency in 1984.
Although there could've been a few more people who have had it although it has not been confirmed.
Other rarest human conditions in the world are fields disease, fibrodysplasia ossificans progressive "Stoneman Syndrome" and NGLY1 deficiency.
Only 2 known cases of field's disease in a set of twin sisters in the UK have been confirmed worldwide.
Field's disease is a mysterious, neuromuscular condition, which causes the progressive degeneration of muscle tissue, which leaves people affected completely reliant on wheelchairs and medical support.
Fibrodysplasia Ossificans Progressiva (FOP / "Stoneman Syndrome") occurs in around 1 in 2 million people, with around 800 confirmed cases globally.
Fibrodysplasia Ossificans Progressiva (FOP / "Stoneman Syndrome") is an ultra rare genetic disorder that causes your body to repair damaged muscles, ligaments and tendons by turning them into bone.
And over time, these extra bones, lock the joints into place and severely limit your movement.
NGLY1 Deficiency affects less than 100 people worldwide.
NGLY1 Deficiency is a profound deficiency of the N-glycanase 1 enzyme.
People with NGLY1 Deficiency are unable to produce tears and have difficulty in moving certain muscles and experience severe global developmental delays.