Diseases are as old as humanity itself. They affect various organs and parts of the human body and are accompanied by various signs, symptoms, and consequences. Inasmuch as the sum total of all diseases known to man is innumerable, some have stood out as particularly deadly.
In the following entry, the top four world’s deadliest diseases of all times in terms of incidence, fatalities, and spatial distribution.
Primarily caused by the Variola major or Variola minor virus, this disease first broke out in 1880. It was declared eradicated by the World Health Organization in 1977 by which time it had killed an estimated 500 million people world over. Some of its most common signs and symptoms were: high fever, chills, headache, severe back pains, abdominal pain, and vomiting.
This is a contagious respiratory illness that is caused by the influenza virus and is spread by coughing, sneezing, kissing, or direct contacts with infected objects. Its most notable signs and symptoms are: fever, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, and general body fatigue. Its global incidence rate as per WHO estimates currently stands at between 20%-30% in children and 5%-10% in adults and accounts for around 250,000 to 500,000 deaths per annum.
The Black Plague
It was a pandemic (a disease that spreads out over a large geographical area) that broke out in 1347 and lasted through to 1351 principally in Western Europe. It was caused by Yersinia pestis bacterium and spread by rats and other rodents that were infested by fleas. In its heyday, it killed a whopping one-third of the European population (around 75 million people). Persons who suffered from it exhibited the following signs and symptoms: painful and enlarged lymph nodes, abdominal pain, chills, fever, general body weakness, headache, and shock.
First reported in 1981, this global pandemic currently infects 75 million people worldwide and has been responsible for 36 million deaths to date. Persons who have the HIV/AIDS experience a breakdown of their immune system; suffer from rapid weight loss; recurring fever; profuse night sweats; extreme and unexplained fatigue; prolonged swelling of the lymph glands in the groin, armpits or neck; chronic diarrhea; sores of the mouth, genitals or anus; pneumonia; blotches on or under the skin or inside the mouth, eyelids or nose; neurologic disorders and depression.
This is an infectious and generally fatal disease that is caused by a filovirus (Ebola virus) and spread primarily through contact with infected bodily fluids. It is very severe and leads to death of up to 90% of its sufferers. The victims do exhibit the following signs and symptoms: nausea and vomiting, bloody diarrhea, red eyes, raised rash, chest pains, cough, stomach pains, severe weight loss, and serious bleeding.