These Diseases Spread by Insects Are Getting Worse in the United States

Insects are not only a nuisance, they can also be deadly. Certain insects contribute to vector-borne diseases, meaning bacteria and viruses that are transmitted through carriers like mosquitoes, ticks, and fleas. Since 2004, the number of vector-borne diseases has been exploding. This creates a serious health threat for every American.

Here is everything you need to know about the 15 most common vector-borne diseases and what you can do to protect yourself.

1. West Nile virus

Mosquito sucking human blood

Mosquito | frank600/Getty Images

  • Transmitted by: Mosquitos
  • Symptoms: Symptoms range from extremely mild to nearly fatal. One in five will develop a fever and other mild symptoms, but one in 150 will develop serious, sometimes fatal, illness.

There have been over 65,000 cases of West Nile virus reported to the CDC between 1999 and 2016. In that same time period, over 2,000 people have died.

Next: This well-known virus can make your babies heads smaller.

2. Zika Virus

Pregnant belly with big mosquito

Mosquitos and pregnancy don’t mesh. | abadonian/Getty Images

  • Transmitted by: Mosquitos and pregnancy
  • Symptoms: Fever, joint pain, headache, muscle pain, conjunctivitis, or rash.

Zika virus is particularly malicious because the symptoms are so mild, they often go unchecked. If a woman is infected with the virus, she can transmit the infection to her child. Most likely, the child will have certain birth defects like microcephaly and other severe fetal brain defects. So far, over 60,000 people have been infected including over 7,000 pregnant women.

Next: Up to 30,000 people a year get this illness.

3. Lyme disease

Female Deer Tick removed from an accidental host.

Tick | JasonOndreicka/Getty Images

  • Transmitted by: Black Legged Ticks
  • Symptoms:  Fever, headache, fatigue, and a characteristic skin rash called erythema migranes

Lyme disease is way more prevalent than you would believe. Anywhere from 15,000 to 30,000 cases are reported each year. Luckily this disease can be treated with a couple weeks of antibiotics.

Next: If you thought this pandemic from the Middle Ages was over, think again.

4. Plague


Flea | 3drenderings/Getty Images

  • Transmitted by: Rodent fleas
  • Symptoms: Symptoms vary depending on the form of plague but can include fever, chills, extreme weakness, abdominal pain, shock, and possibly bleeding into the skin and other organs.

Plague comes in many different forms and yes, this is the same plague that scorched Europe in the Middle Ages. Plague still infects people in the U.S. and has the potential to kill them. The bacteria act extremely fast, so if you ever develop any of these symptoms head immediately to the hospital.

Next: Here’s one you may have never heard of before, and we hope you never get it.

5. Tularemia

Encephalitis Virus

Tick | nechaev-kon/Getty Images

  • Transmitted by: Tick and deer fly bites, skin contact, contaminated water, and inhalation.
  • Symptoms: Signs and symptoms of Tularemia vary depending on how you were infected. All forms result in a high fever, but can also include blisters, ulcers,  or swollen lymph glands.

Tularemia infects humans and animals. Rodents, mostly hares and rabbits, are the most susceptible to the bacteria. When a population is infected, it can move through very fast through the affected area. It has been known to kill large swaths of animals.

Thousands of cases in humans have been reported. Even though the blisters and ulcers can appear on your skin, the actual infection is hard to diagnose. When identified, a few weeks of antibiotics usually takes care of it.

Next: This one virus has an entire branch of a CDC department dedicated to it.

6. Dengue virus

Mosquito sucking

Mosquito | fotomarekka/Getty Images

  • Transmitted by: Mosquitos
  • Symptoms: Symptoms of Dengue can be severe and include headaches, bleeding, rash, bloody vomit, and black stools.

The Dengue virus is so prevalent in the world that the CDC has an entire branch dedicated to it. As many as 400 million people are infected annually. There isn’t a vaccine for this drug yet. Early detection is the most reliable way to avoid dying from the infection.

Next: If you don’t treat this infection right away, you could lose a leg or worse.

7. Rocky Mountain spotted fever

sick man blowing his nose in bed

This fever will leave you feeling horrible.  |

  • Transmitted by: Ticks
  • Symptoms: Fever, headache, nausea, vomiting, and rash.

The name sounds a little whimsical but RMSF is a fairly vicious bacterial infection. The number of cases has grown by almost 1,000% since 2000. If the infection is allowed to go for too long, areas affected could be amputated, or you could suffer hearing loss or paralysis.

Next: The fever is so strong it can alter your mental state.

8. Typhus fevers

girl getting lice treatment

Lice is a pain to get rid of. |

  • Transmitted by: Fleas, lice, and chiggers
  • Symptoms: Common symptoms include fever, headaches, and sometimes rash, altered mental status, ranging from confusion to coma or delirium.

Typhus presents itself in three different ways, but all of them result in horrible illness. Epidemics of Typhus have killed millions in our history. Like most bacterial infections, early detection and treatment with antibiotics will help people recover quicker.

Next: This sounds like an excuse you would give your boss for not coming into work.

9. Bourbon virus

Beetle on leaves

Other insects can carry this virus. | Yuri Kadobnov/AFP/Getty Images

  • Transmitted by: Tick or other insect bites
  • Symptoms: fever, tiredness, rash, headache, other body aches, nausea, and vomiting

This is one of the newest vector-borne illnesses discovered by the CDC. In fact, this virus is so new that doctors are only just discovering symptoms associated with the virus. There are no known treatments or vaccines for this virus yet, so the only thing you can do is get to the hospital to at least treat some of the symptoms.

Next: This next virus is named for the very area that it affects. 

10. Heartland virus

Side view of sick woman having coffee

This virus will leave you feeling horrible. |

  • Transmitted by: Ticks
  • Symptoms: Fever, headaches, fatigue, muscle aches, and diarrhea

This is another disease that was only recently discovered. Symptoms are hard to pin down because they have only been able to identify the virus a short while ago. Reports of the disease are primarily in the Mid-West and Southern states.

Next: If left untreated, your brain could swell and you could die.

11. Saint Louis encephalitis virus

Aedes aegypti Mosquito

Mosquito | frank600/Getty images

  • Transmitted by: Mosquitos
  • Symptoms:  fever, headache, nausea, vomiting, and tiredness

Often times with an SLEV infection, swelling of the brain can occur. That can lead to brain damage or death. This commonly occurs in older people who have been infected with the disease.

Next: This sickness just won’t quit after you catch it.

12. Tick-Borne Relapsing Fever

Sick woman cough in ved under blanket

Fevers are never fun | samotrebizan/iStock/Getty Images

  • Transmitted by: Ticks
  • Symptoms: fever, headache, muscle and joint aches, and nausea

Just imagine getting sick and then feeling better only to get sick again. TBRF infects people all over the western United States and is “typically linked to sleeping in rustic, rodent-infested cabins in mountainous areas,” according to the CDC.

Next: Seizures, coma, paralysis can happen from this serogroup.

13. California serogroup viruses

A seizure and disorientation are common. |  Netflix

  • Transmitted by: Mosquitos
  • Symptoms: Asymptomatic or mild fever to encephalitis or mengioencephelitis

California serogroup viruses are a catch-all for three different viruses spread by mosquitos: California encephalitis, La Crosse encephalitis, and Jamestown Canyon. The viruses spread easily and are often undiagnosed. Most people don’t know they have it. If left untreated, you could become confused and disoriented or suffer seizures, coma, and paralysis.

Next: Here’s one you probably have never heard of, but it has spread across the Americas in just a few years.

14. Chikungunya Virus

Aedes aegypti mosquitoes

Mosquitos | Christophe Simon/AFP/Getty Images

  • Transmitted by: Mosquitos
  • Symptoms: Fever, joint pain, headache, muscle pain, joint swelling, or rash.

Chikungunya virus is indigenous to Africa, Asia, Europe, and the Indian and Pacific Oceans. In 2013, however, it was discovered in the Americas for the first time by way of the Carribean. Since then it has covered both South and North America.

There is no cure or vaccine for the virus.

Next: This is the rarest of these emerging viruses, but it is still something to worry about.

15. Powassan virus

Adult Female, Adult Male Nymph, & Larva Ticks

Ticks | Getty Images

  • Transmitted by: Ticks
  • Symptoms: Fever, headache, vomiting, weakness, confusion, loss of coordination, speech difficulties, and seizures

Powassan virus is very dangerous. Approximately half of the people who survive Powassan “have permanent neurological symptoms, such as recurrent headaches, muscle wasting, and memory problems,” according to the CDC. 10% of the reported cases are fatal.

Next: Here’s the only way to protect yourself from these horrible diseases.

Prevention is the only defense

Anti mosquito spray

Prevention is key. | macrovector/Getty Images

The CDC has a comprehensive list of all that is being done to prevent the spread of these pathogens. We created a very basic list of things to do below:

  • Use Mosquito repellent
  • Wear long sleeves and pants
  • Keep screens on windows when they’re open
  • And use bed nets when possible

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