20 Most Dreaded Diseases in the World

6 minute read

By John Hardy

According to The World Health Organization, there are officially more than 12,420 different, documented diseases in the world. You can learn more about each and every one of them by searching online.

Despite all those dreaded diseases, there’s good news. Life expectancy rates have been on the rise for decades. That said, diseases are still out there. Here are 20 of the most dreaded diseases in the world today.


Cancer is the undisputedly the most dreaded disease in America. Although stats show that cancer is actually the No. 2 leading cause of death behind heart disease, it’s still the most dreaded disease. This is likely due to cancer directly or indirectly touching so many lives, constant publicity and news reports, and because of how quickly cancer can strike and the suffering it can cause.

While research and treatments have brought encouraging advancements for the treatment and survival rates of some cancers (like breast and skin cancer), treatment for many cancer types can involve painful surgeries, radiation and chemotherapy that can lead to unpleasant side effects. Some common cancers, like lung and pancreatic cancer, have low five-year survival rates.

Dementia and Alzheimer’s

Dementia is a dreaded disease, but often misunderstood. It is NOT one single disease, but a general term to describe impaired memory, communication and thinking. Dementia risks increases with age but it is NOT a normal part of aging.

Alzheimer’s disease is probably the most commonly known, and most dreaded form of dementia. Recent censuses estimate 5 million Americans aged 65 years or older are living with Alzheimer’s, and that Alzheimer’s accounts for 60-80 percent of all cases of dementia.

It’s dreaded because it’s one of the most misunderstood and relatively untreatable forms of dementia. Plus, it taps into the common fear of unable to care for oneself, burdening others and losing memory about life and family.

Coronary Heart Disease

The numbers confirm that coronary artery disease is the deadliest disease in the world.  It happens when the blood vessels that supply blood to the heart become narrowed.

The risk factors are high blood pressure, high cholesterol, being overweight, smoking, other lifestyle factors and family history. According to the Centers for Disease Control and Prevention (CDC), over 600,000 Americans die of heart disease every year.


Stroke is when an artery in the brain is blocked or leaks. Oxygen deprived brain cells die within minutes. Each year, more than 6.7 million deaths from stroke happen around the world. Risk factors include diet, exercise, smoking, alcohol, family history, ethnicity, age, high blood pressure, high cholesterol, and diabetes.


Diabetes is a group of diseases that affect insulin production. Type 1 and Type 2 diabetes are common. With Type 1, the pancreas is unable to produce insulin. The cause is not known.

With Type 2, the pancreas doesn’t produce enough insulin or can’t use it efficiently. It’s caused by various factors, including poor diet, lack of exercise, and being overweight.


Chronic Obstructive Pulmonary Disease (COPD) is a lung disease that makes it hard to breathe. It causes about 3 million deaths each year.

About 64 million people around the world live with COPD. The main causes are tobacco use and second-hand smoke exposure. It affects men and women but, sadly, there is no cure.

Respiratory Cancers

Bronchitis, Emphysema and Lung Cancer are all respiratory cancers. The main causes are smoking, second-hand smoke, and environmental toxins. These diseases can severely reduce the quality of life of those who suffer from them.

Parkinson’s Disease

Parkinson’s Disease is a dreaded, long term disease and affects the central nervous system. Early on, the symptoms include shaking, rigidity, slowness of movement and difficulty walking.

Depression, anxiety, thinking, sleep and behavioral problems can also happen. The cause of Parkinson’s is not known, but genetic and environmental factors are connected. There is no known cure for Parkinson’s disease—yet!

Neurological Disorders

Neurological disorders result from damage to the brain, the spinal column and the nerves. A dreaded disease, mostly because the poor quality of life and loss of independence that can occur either quickly or progressively over a long period of time.


ALS/Lou Gehrig’s Disease (amyotrophic lateral sclerosis) involves the death of neurons that control voluntary muscles. ALS is characterized by stiff muscles, muscle twitching, and gradually worsening weakness due to muscles decreasing in size. It is a dreaded disease because it results in difficulty speaking, swallowing, and eventually breathing.

Multiple Sclerosis

Multiple Sclerosis (MS) is a dreaded disease of the central nervous system, marked by weakness, numbness, a loss of muscle coordination and problems with vision, speech, and bladder control.

Most people experience their first symptoms of MS between the ages of 20 and 40. Most MS patients experience blurred or double vision, red-green color distortion and blindness in one eye, muscle weakness in extremities and difficulty with balance.

Zika Virus

Zika Virus is spread mostly by the bite of an infected mosquito. They are aggressive daytime biters and also bite at night. The most common symptoms are fever, rash, joint pain and red eyes.

Zika can be passed from a pregnant woman to her fetus and infection during pregnancy can cause certain birth defects. So far, there is no vaccine or medicine for treating or preventing Zika.

Kidney Disease

The two kidneys clean the blood and maintain its balance of salt and minerals, and help control blood pressure. When the kidneys are damaged, waste products and fluid can build up in the body, causing swollen ankles, vomiting, weakness, poor sleep, and shortness of breath. If not treated, diseased kidneys may eventually stop working completely. It is often caused by long-term diabetes and high blood pressure.


HIV is a virus that attacks the immune system and can cause AIDS (acquired immunodeficiency syndrome), a dreaded, chronic, life-threatening condition. According to the Foundation for AIDS Research (amfAR), since the start of the pandemic, almost 40 million people have died due to HIV/AIDS.

There is no known cure, although treatments exist and slow the virus’ progression. It is transmitted through direct contact with infected blood, semen, vaginal fluid, pre-seminal fluid and breast milk.

Hepatitis C

Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver. During the initial infection, people often have mild or no symptoms and occasionally a fever, dark urine, abdominal pain, and yellow tinged skin.

It is spread primarily by blood-to-blood contact associated with intravenous drug use, poorly sterilized medical equipment, needle stick injuries in healthcare, and transfusions. There is no vaccine against hepatitis C.


Tuberculosis (TB) is a lung condition caused by bacteria that is often successfully treated. The majority of TB-related deaths happen in poorer countries. It is one of the top causes of death for people who have HIV.

Pre-Term Birth Complications

According to the World Health Organization, as many as 1.1 million deaths were due to prematurity and complications due to low birth weight. Lack of skilled medical care makes this a huge problem in developing countries. Many newborn deaths could be avoided with good prenatal and postnatal care.


Although North America usually hears about this deadly virus in the news from Central Africa, just the mention of the word makes it a dreaded disease. Ebola hemorrhagic fever can be fatal with symptoms ranging from fever, vomiting, diarrhea, generalized pain or malaise, to sometimes even internal and external bleeding.

The Flu

Influenza, also known as the flu, refers to the infectious disease that affects birds and mammals and is caused by influenza viruses. In the case of humans, symptoms are fever, sore throat, muscle pains, severe headache, coughing, weakness and general discomfort. In severe cases, influenza can lead to pneumonia, often with fatal consequences, particularly among young children and the elderly. It’s easy to mistake influenza for the common cold, though influenza is a much more severe disease caused by a different type of virus, and causes 36,000 deaths a year.

Diarrheal Diseases

Health professionals refer to diarrhea that lasts for more than a few days as a diarrheal disease when the body loses too much water and salt. Death due to dehydration is possible with serious diarrheal disease.

Diarrheal disease is usually caused by an intestinal infection transmitted through viruses, bacteria, or even parasites. Infection is often spread through contaminated water or food and happens mostly in developing countries with poor sanitary conditions.

John Hardy