The 20th century was an amazing time of discovery and medical advancements, from learning about how infectious diseases work to uncovering ways people can combat them. For a general readership, the following microorganisms were some of the most alarming emerging infectious diseases of the last century.
Human Immunodeficiency Virus (HIV)
HIV, the causative agent for Acquired Immune Deficiency Syndrome (AIDS) was believed to have evolved from a primate form and incidentally infected humans via contaminated bush meat. It was unique to researchers because it was the first known virus to directly attack the immune system, and its discovery in the 1980’s caused mass hysteria among health care workers.
Just as smallpox was eradicated, monkeypox slipped into its place. Monkeypox has not yet shown widespread death, but it does have that potential with the same symptoms as smallpox. Although it is mostly observed in Africa, the import of animals has allowed this virus to travel worldwide.
Hemorrhagic fevers develop from two notable viruses discovered in the mid-20th century. Occasional outbreaks of Ebola or Marburg viral infections still make the news, with their devastating outcomes and widespread dissemination. These viruses cause catastrophic organ shutdown leading to a high rate of death in infected individuals.
Most people have head of bovine spongiform encephalopathy (BSE), also called mad cow disease, but a general readership may not realize this is a type of prion disease. Prions are like tiny pieces of microorganisms that can infect the brain and nervous system of all living things, often leading to dementia. The scariest part is that prions are difficult to detect and destroy because they are not technically alive.
Hantavirus Pulmonary Syndrome
The hantavirus popped up in North America during the middle of the last century. Doctors were initially confounded when patients showed up with acute pulmonary distress symptoms. Unfortunately, there is no good treatment or cure for this virus and the immune system tends to go overboard by flooding the lungs with fluid.
Honorable mentions for terrifying diseases discovered in the last century are Avian flu, West Nile Virus, Nipah Virus and Severe Acute Respiratory Syndrome (SARS). Although the last one was only discovered this century, it provides a great example of how humanity continues to be challenged by emerging infectious diseases. Antibiotics and vaccines forever changed the evolutionary timeline of the human race, but new diseases crop up and surprise us.