
Mosquito-borne diseases cause around 1 million deaths each year, making this tiny insect the most dangerous animal in the world. Here are the who (you actually), what, when, where, why, and how of this ranking.
What Makes Mosquitoes so Dangerous?
Their bites may irk you, but, if the biter carries a virus or parasite, its mosquito-borne disease can cause 1 million deaths worldwide each year. This makes mosquitoes the most dangerous animal in the world.
As just one example, the World Health Organization (WHO) estimates almost half of the Earth’s population was at risk for malaria in 2021, and it was responsible for 619,000 fatalities. Mosquito bites caused around 247 million cases worldwide that same year. And now, according to news reports, malaria has been found locally in the U.S.
Why Are Mosquitoes the Most Dangerous Animal in the World?

Photo Credit: nopparit / Canva Pro / License
Mosquitoes are at the top of the list of most deadly animals because they carry a number of diseases that can kill humans and animals. Per the Centers for Disease Control and Prevention (CDC), mosquitoes carry the following viruses and parasites that can cause fatalities:
Viruses
- Cache Valley
- Chikungunya
- Dengue fever
- Eastern equine encephalitis
- Jamestown Canyon
- Japanese encephalitis
- La Crosse encephalitis
- Rift Valley fever
- Ross River virus disease
- St. Louis encephalitis
- West Nile
- Yellow fever
- Zika virus
Parasites
- Dirofilariasis (dog heartworm)
- Lymphatic filariasis
- Malaria
Your Pets
Mosquitoes also bite your pets and cause serious conditions, too. In cats, they can cause heartworms and allergic reactions. They can also cause heartworms, West Nile virus, and encephalitis in dogs.
What Are Mosquitoes?

Mosquitoes are a type of fly and belong to the order Diptera. More than 3,700 species of mosquitoes exist worldwide, and over 200 species live in the U.S. However, only 12 or so cause disease when they bite humans. Anopheles, Culex, and Aedes mosquitoes are usually responsible for human bites in the U.S.
Mosquitoes hatch from eggs that often form rafts and then go through a larval stage and a pupal stage before becoming full-grown insects. The female mosquito needs blood to produce eggs. So she searches for the blood she needs. And you and your family – even your pets – are at risk for her bites.
How Do Mosquitoes Bite?

When a mosquito bites, its proboscis pierces your skin. Through this appendage, the deadly creature sucks between 0.001 and 0.01 mL of blood. That doesn’t sound like much, but as it feeds, it injects saliva into your skin. This generally results in a bump and itching. Bites can result in disease if the mosquito’s saliva contains a virus or parasite.
When Do Mosquitoes Bite?

A mosquito can be active at any time of year, depending on the climate. In the U.S., they become active in the spring when temps are consistently above 50 degrees and stop biting in fall when temperatures fall below 50 degrees. These insects are most active in warm, humid areas around 80 degrees. During the winter, some females hibernate.
During the day, they become most active during the early morning and early evening hours (dawn and dusk), though some species (like Aedes aegypti) are daytime biters.
Where Can Mosquitoes Be Found?

Adult mosquitoes can be found everywhere. They’re either flying about, looking for a meal, or they’re resting somewhere hidden. They like to rest near your home in wooded areas, where ponds, trees, and tall grasses can be found. They also like to settle near bushes, gutters, birdbaths, and air conditioners. Any standing water will do too.
They can also be inside your home. There, they like to rest in flowerpots, under furniture and sinks, and in basements and showers.
FAQ
Ever wonder how these little biters find their next meal? Let us count the ways:
• CO2: Mammals – that’s humans, dogs, and cats – exhale CO2, which lures mosquitoes from up to 115 feet away, according to the American Mosquito Control Association. Once these little bugs home in on a source, they zigzag around until they can definitively locate it.
• Body odor: Think of the smells (e.g., sweat, lactic acid) your body produces naturally. These smells help mosquitoes find you after they lock on to your CO2.
• Temperature: Studies show that the average human body temperature (98.6 degrees F) attracts mosquitoes.
• Places near their favorite spots: If you hang out near standing water or shady areas (e.g., bushes, tall grasses), you might be placing yourself within mosquito population areas.
• Movement: Exercise (or movement) may help mosquitoes find you. It makes you stand out visually, and your body releases more CO2 as you move.
• Blood type: People with blood type O attract more mosquitoes than those with other blood types.
• Your beverage and your clothing: Drinking a beer and any other alcoholic beverages can attract mosquitoes, as can wearing perfume. And wearing short-sleeved or sleeveless shirts and shorts provides more skin where mosquitoes can land and then bite.
Here’s how to prevent mosquito bites and keep your yard safe:
Pour out standing water in all containers such as wheelbarrows, watering cans, bird baths, and old tires. Drill holes in containers so water drains. Or turn them upside down, cover them, or throw them out.
Use insect repellent, especially one registered as safe and effective by the Environmental Protection Agency (EPA), with at least one of the following active ingredients:
• DEET, popular in the best conventional mosquito repellents
• Picaridin
• IR3535
• Oil of lemon eucalyptus, popular in the best natural mosquito repellents
• Para-menthane-diol (PMD)
• 2-Undecanone
Cover up by wearing long-sleeved shirts and long pants and apply permethrin to them (but never to your skin).
Button up your house by using air conditioning or window and door screens. Or sleep under a mosquito net.
Use essential oils made from plants that repel mosquitoes, such as basil, citronella, peppermint, and sage.
Prevent them from becoming adult mosquitoes by treating standing water with larvicides.
Pro Tip: Don’t forget Fido! Check out our list of the best dog mosquito repellents to keep Fido bite-free.
As far as anyone knows, mosquitoes have never transmitted HIV by biting a human because HIV doesn’t replicate in mosquitoes. They actually digest HIV instead of passing it on.
They cannot transmit it via blood on their proboscises either. It is estimated that, to transfer the virus from someone with to someone without HIV, a mosquito would have to bite someone with HIV approximately 10 million times before biting the person without HIV.
Some of the other animals that made the list of the world’s deadliest animals include the following. These can be found in Africa (especially sub-Saharan Africa), rainforests, northern Australia, South America, India, the Indo-Pacific, Colombia, and even the U.S.
• Hippos
• Saltwater crocodiles and freshwater Nile crocodiles
• Alligators
• Assassin bugs
• Tsetse fly
• Box jellyfish
• Freshwater snails
• Scorpions
• Ascaris roundworms
• Cape buffalo
• Great white sharks
• Poison dart frog
• Venomous snakes, including from the snake bites of the saw-scaled viper and the Inland Taipan
• Pufferfish
• Tapeworms
Mammals on the list include the African elephant and canines (yes, dogs). Humans often show up on the list as well.
Call the Pros
Preventing mosquitoes, the most dangerous animal in the world, from biting you and your family can be tricky. Why not put your safety in the hands of the professionals? Pest Gnome connects you to the best pest control experts near you.
Main Image Credit: Piman Khrutmuang’s Images / Canva Pro / License