10 Diseases That Used to Be Death Sentences

You probably know the basics of human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS). Back in the disease's terrifying heyday of the 1980s and early '90s, even experts knew precious little about how to treat HIV, which is usually transmitted through unprotected anal or vaginal sex or by sharing drug needles [source: CDC]. Common symptoms include rashes, fever, enlarged lymph nodes and a sore throat. Over time, if untreated, a body with HIV loses the ability to fight off infections, which leads to AIDS [source: CDC]. Contracting HIV used to be a death sentence, but not anymore, thanks to the introduction of antiretroviral drugs in the mid-1990s.

"In the early days, people diagnosed with HIV had a life expectancy of about eight years," says John Brooks, M.D., medical officer in the Division of HIV/AIDS Prevention of the Centers for Disease Control and Prevention (CDC). "Today, a person who is promptly diagnosed with HIV and appropriately treated can look forward to a close-to-normal life span." Modern antiretroviral therapy can be administered in as little as one pill per day, eliminating symptoms, but stopping short at actually curing the disease, of course [source: WebMD].

In 2010, AIDS was the seventh leading cause of death among the 25-44 age bracket in the U.S., having peaked at No. 1 in both 1994 and 1995 [source: The Henry J. Kaiser Family Foundation]. Yet, the epidemic is far from over, with about 34 million people in 2014 infected around the globe, often unaware they even have HIV or AIDS [source: amfAR].

Ever seen a period movie where the heroine coughs droplets of blood into a hanky? You've witnessed a re-enactment of the disease that was a leading cause of death in the U.S. and Europe in the late 1800s and early 1900s [source: NIH]. Back in 1892, tuberculosis (TB) was responsible for one out of seven deaths in the U.S. [source: Haynes].

Also known as consumption, TB spreads when a person infected with Mycobacterium tuberculosis coughs, sneezes or otherwise transmits droplets through the air to someone else [source: CDC]. Roughly a third of the global population is infected with latent TB, which yields no symptoms and is not contagious in that stage, but probably will be in time [source: WHO]. Once it evolves into TB disease, the bacteria usually wages war on the lungs; hence the notoriously bloody cough, as well as chills, night sweats and fever.

Antibiotics and upgraded living conditions have significantly contributed to the decline of TB in modernized countries. Unfortunately, it continues to plague developing countries, with roughly 95 percent of TB diagnoses and deaths situated squarely in their borders. However, treatment and containment efforts are making a dent; the worldwide death rate from TB dropped 45 percent between 1990 and 2012. Nevertheless, multi-drug resistant TB is at very high levels [source: WHO].

If you're ever bitten by a dog, bat, raccoon or other angry animal, you should hustle to a hospital with haste. Even if the animal is more bad-tempered than rabid, this disease isn't something you want to take a chance on. Once symptoms appear, rabies is transformed into a painful illness that fatally attacks the central nervous system, causing confusion and delirium and eventually death [source: CDC].

However, rabies is very treatable as long as it's caught before symptoms emerge [source: Humane Society]. Most people know when they've been bitten by an animal, making the risk easy enough to assess, and post-exposure treatments and vaccines are available to stop symptoms before they start [source: CDC]. Awareness and treatment are credited with keeping the U.S. death toll at two or three people per year, down from 100 in the early 1900s [source: CDC].

Also known as the Black Death, the bubonic plague seems too terrifying to be true, but the sad fact is that it killed more than 75 million people in 1300s. The horrific spread began in Asia and worked its way into Europe, where about one-third of the continent's population was infected, suffering through myriad symptoms like apple-sized swellings that oozed blood and pus, aches, pains, vomiting, fever and chills, before dying. Although the initial phase wound down around the 1350s, the disease has continued to periodically pop up around the world [source: History].

We now know that bubonic plague is spread by infected fleas and rats, and is best kept under control with public health and improved sanitation efforts [source: History]. That doesn't mean it's history. More than 10,000 people contracted the disease in the Congo between 2000 and 2009. Even in the U.S., 56 people caught the plague during that same period (seven died)[sources: Huffington Post and Bloomberg]. Antibiotic treatment can now quickly cure this once definite death sentence, but it must be done fast. If the bacteria reach the lungs, it becomes pneumonic plague, which can rapidly turn fatal [source: WHO].

One of the oldest diseases in the world (Ramesses V of Egypt, who died in 1157 B.C.E. apparently had it), smallpox killed 300 million people worldwide in the 20th century [source: Flight]. The condition got its name to distinguish it the "great pox" (aka as syphilis). This contagious disease is spread by face-to-face contact with an infected person. Symptoms include fever, headache and severe back pain followed by telltale red pustules all over the body, which leave pitted scars [source: WHO].

Smallpox was also the first disease for which a vaccination became available. Britain's Dr. Edward Jenner had heard that milkmaids who had contracted the mild disease of cowpox never developed smallpox. In 1796, he tested the theory by injecting a boy with some pus from a cowpox pustule and saw that it gave him immunity to smallpox [source: Flight]. The breakthrough was enormous and paved the way for the science of vaccination. In 1959, the World Health Organization decided to eradicate the disease from the planet by isolating smallpox patients and vaccinating everyone in an area where smallpox was detected. In 1980, the organization declared victory; smallpox was no more [source: WHO].

Think of syphilis as the granddaddy of sexually transmitted diseases (STDs). One of the oldest on the books, it's suspected to have affected many over the centuries, including England's King Henry VIII and composer Franz Schubert [source: History]. Syphilis is highly contagious because symptoms are often confused with other problems, if they're apparent at all. Sores can be easily mistaken for mundane annoyances like ingrown hairs, for example, or they hide in the anus or other crevices. If left untreated, syphilis can progress through the uncomfortable first and second stages into the third stage, which is characterized by dementia, heart disease, organ failure and other serious, life-threatening issues [source: Brown University]. No wonder it was referred to in centuries past as the "great pox" or just "the pox."

This disease used to be very widespread. In the early 1900s, it was estimated that 10 to 15 percent of the U.S. population had syphilis [source: Jabbour]. After the introduction of penicillin in the 1940s, the death rate tumbled. Incidence of primary and secondary syphilis in the U.S. in 2013 was down to around 5.3 cases per 100,000 people (but double the all-time low rate reported in 2000 of 2.1) [source: CDC]. Prevention and early treatment of this disease is urged to prevent resurgence and other long-term health complications.

Every year, influenza (or "the flu") does its best to confound vaccine-producing scientists. Sometimes vaccines work pretty well, and other years they miss the mark a bit. This is because flu viruses constantly change, leaving vaccine makers to take an educated guess at creating a treatment that will effectively combat that year's most common strains [source: FLU.gov].

Most of the time, seasonal flu causes significant illness and discomfort in the form of fever, chills and body ache, but this highly contagious illness usually isn't life-threatening. Certain groups are at higher risk, like people over age 65, young children, people with compromised immune systems and pregnant women [source: WHO].

Flu outbreaks have occurred that devastated populations, however. The worst on record was probably the 1918 outbreak that killed approximately 40 million people worldwide [source: National Institute of Allergy and Infectious Diseases]. Science today appears to be on our side, thankfully. In 2014, there were 250,000 to 500,000 deaths from influenza worldwide [source: WHO].

As recently as the 1940s, the leading cause of death among women in the U.S. was cervical cancer. But the advent of the Papanicolaou(Pap) test contributed to a 60 percent decline in cervical cancer death rates and incidence in the United States between 1955 and 1992 [source: NIH]. The test, which is typically administered during annual gynecological visits, can identify precancerous cells before they have a chance to get out of control.

Pap tests check for the presence of human papillomavirus, some versions of which are transmitted sexually, and can cause cell changes that result in cervical cancer [source: Haynes]. In recent years, experts have begun encouraging adolescent girls to receive the HPV vaccine, which can altogether prevent certain types of the virus [source: National Cancer Institute]. Nearly 4,000 women died in 2010 of cervical cancer, although the rate is dropping by the year [source: CDC].

"Within our lifetimes, we may see a country free of women dying from cervical cancer if screening and vaccination is done in an appropriate and timely way," explains David Espey, M.D., acting director in the Division of Cancer Prevention and Control at CDC.

Mosquitos pack the potential for more than just annoying, itchy red bumps. In fact, they transmit the Plasmodium parasite that causes malaria, which is characterized by chills, sweating and fever, among other symptoms [source: National Institute of Allergy and Infectious Diseases]. Although it has been largely eradicated in North America, the Caribbean and much of Europe, malaria is still a serious concern in tropical and subtropical countries, particularly in Africa and Asia.

Public health initiatives have rendered malaria both preventable and treatable, as long as it's done correctly and quickly. Rapid diagnostic tests, followed by tailored antimalarial treatments have saved at least 3 million lives since 2000. Between 2000 and 2013, global deaths from malaria have fallen 42 percent [source: WHO]. As with most of these diseases, prevention with such new technologies as insecticide-treated bed nets is encouraged by infectious disease experts [source: Haynes].

Pneumonia is sneaky, to say the least. It often strikes in the midst of another illness, like bronchitis or the flu. But it's a lot less of a death sentence than it used to be. In 1900, it was the No. 1 cause of death in the U.S. In 2006, pneumonia was the eighth most common cause of death, along with influenza [sources: American Lung Association and CDC].

Caused by fungi, bacteria, viruses or other small germs, pneumonia occurs when said germs reach and infect one or both lungs [source: American Lung Association]. Although it is typically treatable, pneumonia is sometimes difficult to get under control, and can cause difficulty breathing, lung abscess and other complications. Bacteria can also invade the bloodstream, potentially causing organ failure [source: Mayo Clinic]. Experts typically advise high-risk groups, particularly people over age 65, to be vaccinated to prevent getting sick or experiencing complications [source: CDC].