27,016. That’s the population density (inhabitants per square mile) of New York City, per the latest census figures. San Francisco: 18,679. Chicago: 11,868. For contrast, less-urban American locales—like Duluth, Minnesota, or Portsmouth, New Hampshire—have population densities of just over 1,000. In other words, city denizens truly are living on top of each other—and, in every instance, it’s a veritable, festering petri dish.
From tuberculosis germs to flesh-eating bacteria to pathogens of the plague (yes, that plague), the urban environs of America are rife with terrifying diseases. Don’t believe us? Scroll on, and see for yourself. We’ve rounded up all the scariest diseases plaguing American cities. So ready the Purell—or, better yet: catch a train straight to the countryside.
First identified in the United States in 1962, Enterovirus D68—or EV-D68—is a member of the enterovirus family, which also houses poliovirus. People who become infected with this virus experience symptoms similar to the common cold, like a runny nose and a fever, but can also suffer from more serious complications like difficulty breathing.
Though few cases of this virus are typically seen by the Centers for Disease Control and Prevention (CDC), 2014 saw a climbing number of instances, with 1,153 people in places like New York and Los Angeles having confirmed respiratory illnesses as a result of EV-D68. This infection is most commonly spread in the summer and fall, so make sure to always be thoroughly washing your hands.
Thanks to modern medicine, rubeola—more commonly known as “the measles”—has all but disappeared in the United States. But recently the country has seen as many as 205 cases per year, as according to the CDC, unvaccinated people who travel internationally continue to bring the disease back home and cause outbreaks. (In 2013, Brooklyn suffered an outbreak of the disease that infected 58 people, all thanks to one traveler.) The infection is most commonly seen in children—unfortunately, they are also the most likely to die from it.
Clostridium difficile, or C. difficile for short, is a bacterium that affects the colon and causes inflammation, or colitis. People with a C. difficile infection experience painful symptoms like watery diarrhea, loss of appetite, and abdominal pain—and many end up in the hospital due to dehydration.
Disturbingly enough, you’re most likely to become infected with C. difficile while taking antibiotics, as this is when the number of infection-fighting agents in your body are lowest. When you’re taking medications, be sure to avoid coming into contact with surfaces potentially contaminated with feces (like a subway pole or a public restroom sink).
The bacteria that cause necrotizing fasciitis enter the body through wounds like minor cuts and abrasions. Once inside the body, these bacteria infiltrate the superficial fascia just below the skin, causing symptoms like severe pain and redness. The infection advances rapidly, so within three or four days, people with it will see blisters and tissue death where there once was little more than a harmless bug bite.
Because this disease progresses so quickly and is often not caught in time to be treated, it often leads to the loss of limbs, and can even be fatal. In fact, from 2003 to 2013, 9,871 people died as a result of necrotizing fasciitis in the United States alone. Several types of bacteria can cause necrotizing fasciitis—and since public transportation is teeming with them, it’s important to watch out for open wounds when traveling through the city.
Legionnaires’ disease is caused by the bacterium Legionella pneumophila, which lives in water systems like air conditioners and grocery store mist sprayers. Similar to other types of pneumonia, this disease manifests in symptoms like coughing, shortness of breath, fever, and muscle aches—but while the death rate for all types of pneumonia is 5 percent, that number is at 10 percent for this specific lung infection. What’s more, this disease has been spotted in recent years everywhere from the Bronx to Southern California, making it one of the scariest city diseases to watch out for.
Of all the diseases caused by a single infectious agent, tuberculosis (TB) is the second largest killer on a global scale, accounting for 1.8 million deaths in 2015. And in 2016, cities all across the country saw cases well above the national average, with San Francisco in particular reporting 11.5 TB cases per 100,000 people.
Hand, Foot, and Mouth Disease
If the name of this disease looks familiar, it’s probably because doctors have been seeing so many cases of it recently. And though the disease normally affects young children, even adults (like New York Mets pitcher Noah Syndergaard) can contract it, so both you and your children should be on the lookout. Symptoms include a sore throat and a characteristic blistery rash on the fingers, the inside of the cheeks, and the soles of the feet (ergo, hand, foot, and mouth).
Though, disgustingly enough, you can get them from the subway, staph infections are relatively harmless if caught early. However, if they’re left to their own devices, such infections can enter into the bloodstream and cause septicemia, or blood poisoning, which is a far more serious problem. When staph bacteria enters the blood, it affects major organs like the brain, heart, and lungs—and nearly 17 percent of people who develop septicemia die as a result of it.
Though a vaccine for mumps has been around since 1967, outbreaks of the disease have already been reported in 47 of the 50 states in 2018, with 1,665 cases reported to the CDC. The virus that causes this disease is easily spread via coughing or even talking, which makes people in close proximity to one another (roommates, transit commuters) especially susceptible. The most well-known symptom of mumps is a swollen jaw, but other warning signs include a fever, muscle aches, and swollen salivary glands. Usually mumps do not cause serious complications, but they have been known to result in everything from meningitis to hearing loss.
Chagas disease is a parasitic disease spread by the triatomine bug, more commonly known as the kissing bug. Though the disease was originally thought to only exist in Mexico, Central America, and South America, several cases have been reported in the United States in recent years, especially in Texas and the South. The migration of this disease to America is especially unfortunate, seeing as it causes nearly 12,000 deaths per year in Latin America via heart complications.
When researchers from the University of Maryland tested the feces of 416 New York City mice, they found strains of Salmonella bacteria, which, if they get into a food supply, can cause salmonella poisoning. Though salmonella poisoning is usually beatable without treatment, the not-so-pleasant symptoms include diarrhea, fever, abdominal cramps, and in severe cases dehydration.
Dengue Hemorrhagic Fever
In 2017, the CDC estimated that the chances of finding Ae. aegypti mosquitos were especially high in warm cities like Miami, Phoenix, and Los Angeles. The problem? These mosquitos carry the dengue virus, which can develop into dengue hemorrhagic fever and cause low blood platelet levels—and circulatory system failure.
Hansen’s disease, formerly known as leprosy, saw more than 200,000 new cases worldwide in 2016, with about 250 of those occurring in America. And while many cases seen in the states are the result of traveling, one study published in JAMA Dermatology found that there have been three different incidences of Hansen’s disease in New York City in which the patients never left the country. Though the disease is curable, it leaves its victims with long-term issues like paralysis and blindness.
Similar to dengue, chikungunya is a prominently Southern city disease spread through the saliva of mosquitos. Within days of being bitten, people infected with the chikungunya virus will experience a fever, headaches, muscle pain, and joint swelling. For most people, chikungunya is not life-threatening or even too serious, but young children, older adults, and people with certain medical conditions are hit much harder when they get infected.
Short for methicillin-resistant Staphylococcus aureus, MRSA is a type of antibiotic-resistant staph infection that especially plagues people in populated areas. Typically, the infection begins as an aching red bump that looks like a spider bite and, if left untreated, the bacteria will make their way inside the body, causing bone, joint, and bloodstream infections that can be fatal.
Toxic Shock Syndrome
Toxic shock syndrome is another fatal condition you can get from staph bacteria. Though it’s regularly associated with tampon use (most commonly from leaving it in too long or using a super absorbent brand), the complication can occur in people of all ages and genders, so long as they have a skin wound through which bacteria can enter. Signs of toxic shock syndrome include vomiting, confusion, a sunburn-like rash, and muscle aches—and if you’re experiencing any of these symptoms and also have an infected wound, then it’s important to call your doctor immediately.
HIV, or human immunodeficiency virus, destroys the white blood cells inside your body that fight off infections, making the body a breeding ground for disease. And according to the CDC, the majority of HIV diagnoses in the United States are found in urban areas, making this disease a threat to city slickers. If left untreated, a person with an HIV infection might also develop AIDS, or acquired immunodeficiency syndrome, which leaves the body especially vulnerable to what are known as opportunistic infections.
Let’s start with good news: According to the CDC, only about seven human plague cases are reported each year in the United States. The bad news? If you happen to be one of the seven people infected with the plague bacteria, you might experience limb loss or respiratory failure. The bacteria that causes this disease is spread via the fleas of rodents, so living in the city puts you especially at risk.
Hantavirus Pulmonary Syndrome (HPS)
Rodents are to thank for yet another deadly disease plaguing the United States. Found in people infected with hantavirus, this respiratory disease causes coughing and shortness of breath, with one survivor of the often-fatal illness describing the feeling of the disease to be like a “tight band around my chest and a pillow over my face.”
As if commuting wasn’t bad enough already, one study from Columbia’s Center for Infection and Immunity found that the rats running around all five boroughs of New York City were carrying strains of the bacteria E. coli. If and when these pathogens find their way into the citizens of the city, they result in everything from painful diarrhea to life-threatening complications.