Top 10 Deadly Bacterial Infections Uniquely Targeting Humans

Prior to the discovery of antibiotics, severe bacterial infections were one of the major causes of human deaths throughout the developed world. We all have probably used antibiotics at some point in our lives to treat an infection.

Before the discovery of penicillin by Alexander Fleming, people died from otherwise small scrapes and cuts through complications of infection. In the modern antibiotic era, being sick is now seen as an inconvenience. Really, who wants to be ill longer than necessary?

But bacteria do more than cost us sick days. They can still kill us despite the discovery of these modern drugs. Bacteria are smart and are figuring out ways to resist antibiotics. There are many infections that currently cannot be treated with any antibiotic, killing tens of thousands of people each year in the United States alone.

Even knowing that unpleasant fact, some bacteria go overboard, not content to give us a flu-like illness. These are the artists of death. So read on . . . because that dirty door handle in the public restroom will never seem the same again.

10 E. coli Hemorrhagic Colitis

E. coli are bacteria that can really make for a crappy day. These bugs usually live in the intestinal tract, minding their own business. They are excreted in fecal matter. One exceedingly bad breed of E. coli makes a chemical called “Shiga toxin.” This is not a character that anyone wants hanging around in his guts.

A human might pick up these bacteria by consuming poorly treated food or water contaminated by excrement. In countries that lack proper water sanitation facilities, this is definitely a problem.

Once in the body, Shiga toxin–producing E. coli get to work causing a lovely disease known as hemorrhagic colitis. Essentially, this means the bacteria will cause such bad, bloody diarrhea that the victim, if untreated, can poop himself to death through severe dehydration, kidney damage, and blood loss.

Treatment includes rehydration with oral and intravenous fluids until the body rids itself of the bacteria.[1]

9 Scarlet Fever

A common killer in the 18th and 19th centuries, scarlet fever still makes its rounds today. It terrorized centuries of humans and was known to kill entire groups of children in families. Many well-known individuals throughout history lost loved ones to this disease, including Charles Darwin, who lost at least one child to scarlet fever.

This disease is caused by a group of bacteria known as group A beta-hemolytic streptococci. Scarlet fever often begins with a sore throat and a fever, commonly known as strep throat. As it progresses, it causes a red, bumpy rash that spreads in a head-to-toe manner, causing the victim to have a red, or scarlet, appearance. In addition, it causes a red, bumpy, strawberry-appearing tongue.[2]

Scarlet fever can cause throat abscesses, heart problems, and kidney problems, leading to death. It is easily treated today with antibiotics but still causes death and long-term injury to victims who do not receive adequate and early treatment.

8 Tuberculosis

If there was one disease that evoked fear in our ancestors at the turn of the 19th century, it was pulmonary tuberculosis, the most common form of the disease. However, it is an ancient sickness, with Egyptian mummies having been found with tuberculosis lesions on their skeletons. This disease has killed quite a few famous people, including Franz Kafka and Henry David Thoreau.

The microorganism Mycobacterium tuberculosis is the cause of all forms of tuberculosis. The most common form, pulmonary tuberculosis, involves a bacterial infection of the lungs. Untreated, the bacteria become walled off in the lungs and can remain dormant for years.

Active infections may lead to a wide variety of pulmonary symptoms, including a bloody cough, weight loss, and trouble breathing. The most severe infections allow the bacteria to spread to other body parts, including the kidneys and skeletal system.[3]

Acutely and chronically ill individuals lost large amounts of body weight fighting this infection, leading to a frail and wasted appearance. As a result, tuberculosis was also known as “consumption” and “the white death.” Treatment includes anywhere from six months to years of antibiotics.

7 Tetanus

Also known as “lockjaw” or “the grinning death,” tetanus is a dramatic illness to behold. It was a noted complication of infected wounds in the Napoleonic Wars. Spread via dirt or contaminated soil, tetanus is caused by the bacterium Clostridium tetani.

This bacterium earns its specialization in death and destruction via its neurotoxin called tetanus toxin. This toxin binds irreversibly at the junction between nerve cells and muscles, which results in the characteristic and dramatic muscle spasms of the disease.

Individuals affected with tetanus undergo severe whole body muscle spasms strong enough to cause locking of the jaw, grinding of teeth, an involuntary smile, and involuntary muscle spasms strong enough to break bones, including the spine. Death can result from paralysis of the respiratory muscles, making breathing impossible, or secondary infections.[4]

Without proper medical care, tetanus is a deadly disease. Treatment includes medications such as skeletal muscle relaxers, antibiotics, antitoxins, immune globulins, and supportive care to survive this deadly infection. A tetanus infection is considered a medical emergency.

6 Meningococcal Meningitis

A nervous system infection is never fun. In meningococcal meningitis, the lining of the brain or spinal cord becomes infected with a bacterium known as Neisseria meningitidis. It still occurs today throughout the world but is most common in sub-Saharan Africa.[5]

Meningococcal meningitis commonly presents as a nervous system infection or as a blood infection. In the former case, the person may have fevers, headaches, neck stiffness, visual changes, and vomiting. In the case of blood infection, the person may develop a purple rash and bleeding into the skin and organs. This infection is deadly, but vaccines have made this disease much less of a threat than it once was.

5 Anthrax

It may surprise many readers to know that anthrax is not just the name of a heavy metal band but also a disease and potential weapon of bioterrorism. Anthrax (caused by the bacterium Bacillus anthracis) is not content to be limited to one body system. Instead, it can be found in three main infectious forms: inhalational, cutaneous (infecting the skin), and gastrointestinal.

Anthrax is considered to be a potential biological weapon because its spores can be transmitted through the air and inhalational anthrax is deadly. It was used in 2001 to contaminate US mail envelopes.

In the cutaneous form of anthrax, an ulcerating lesion develops. As long as it is contained and treated without spreading, this is a milder form of the disease.

The inhalational form, however, is a bigger problem. Once inhaled, anthrax first causes flu-like symptoms. Later, the victim begins to feel chest pain and shortness of breath. Within days, almost all patients who progress with this form of the disease die of blood infections. If caught early enough, the disease can be treated with antibiotics.[6]

The gastrointestinal form of anthrax is not pleasant, either. It is obtained from eating undercooked meats. In this type of anthrax, ulcers can form anywhere in the infected portion of the gastrointestinal tract—from the mouth to the anus—which can lead to serious bleeding.

Anthrax can also infect the brain and spinal cord. Due to its many potentially deadly forms, anthrax has set a high bar of expectations for any band bearing its name.

4 Leptospirosis

Unlike other diseases, leptospirosis can be unassuming in terms of its symptoms. Coiled and spiral types of bacteria called Leptospira cause leptospirosis. It is rare in the United States and can be spread from animals to humans, often through animal urine.[7]

The symptoms of leptospirosis are vague. An infected person can have no symptoms at all. In other cases, symptoms include yellowing of the skin and kidney failure, leading to death. The latter form of the disease is more severe, and the syndrome of this infection was described as Weil’s disease.

3 Syphilis

Sexually transmitted infections are becoming more common in the United States. Whether dating apps or changing culture is to blame, there’s no doubt that we all need to be careful in our sexual encounters.

As a sexually transmitted disease, syphilis (aka the “great imitator” for its wide variety of presentations) has a long history of shame. Countries often blamed each other for the disease, attributing it to the “other” population. Outbreaks in wartime decades were common across populations. Famous figures were not spared, and it is suspected that Vincent van Gogh and Beethoven may have contracted this sickness.

Syphilis is caused by the bacterium Treponema pallidum and occurs in three stages, known as primary, secondary, and tertiary. In the primary phase, an ulcerating lesion (chancre) appears, usually on the genitals. The lesion may resolve or may never be noticed.[8]

As the disease progresses, the patient will develop flu-like symptoms and enter into the secondary stage. A widespread rash may appear, along with hair loss, headaches, and liver inflammation. The disease may lie dormant for up to 30 years, in which the late or tertiary phase will develop.

In this final phase, the patient may develop disfiguring lesions, heart problems, a central nervous system infection, and even insanity in a condition known as “general paresis of the insane.”

2 Toxic Megacolon Associated With Clostridium difficile Colitis

Diarrhea is not just an embarrassing reason to miss work. While most of us have probably had a passing case of diarrhea from a number of causes, it’s safe to say that many people have not had the sort of intestinal infection that causes a condition known as toxic megacolon.

In this condition, the intestines become infected and swollen and the patient becomes very ill. In the most serious cases, the intestines can become so swollen that they burst, requiring emergency surgery. Although many different bacteria can cause toxic megacolon, Clostridium difficile is a deadly cause of toxic megacolon.

Infection with Clostridium difficile occurs when the deadly bacteria overwhelm the normal bacteria in the gut of a person. If left untreated, it can cause serious intestinal inflammation and swelling. Severe cases of toxic megacolon, even without perforation, have been known to result in almost total intestinal resection to save the life of the patient.[9]

1 Necrotizing Fasciitis

Also known as “flesh-eating bacteria,” necrotizing fasciitis is nothing to laugh about. Although the bacteria do not actually eat the flesh, they do infect the tissue and underlying structures which leads to tissue death and sloughing. Many different types of bacteria can cause necrotizing fasciitis.[10]

It was first described during the US Civil War in a rapidly progressive series of cases in which individuals had necrotizing fasciitis of the genital region. A multidisciplinary team, including a surgeon to cut away the infected tissue, is almost always necessary, and amputations may occur.

I am a healthcare provider and an entrepreneur. In my free time, I like to exercise and enjoy the outdoors.


Written by Ryan Rauch

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