Know Your Risk: Important Vector-borne Diseases in the Northeastern United States

- Vector-borne disease cases can be found throughout the United States and are caused by mosquito, tick and flea associated pathogens.

Cases of vector-borne diseases are increasing at a concerning rate.

The CDC has reported that there have been a tripling of vector-borne disease cases in the United States between 2004 and 2018.

There are numerous vector-borne diseases in the United States, but the most common are West Nile encephalitis, eastern equine encephalitis, and Lyme disease.

Knowing more about these diseases and how they circulate, will help you understand your risk and protect yourself from these pathogens.

West Nile Virus is a zoonotic pathogen that can make its way to humans and animals through a mosquito bite.

Let's look at that cycle in more detail.

West Nile virus is naturally maintained in populations of songbirds and transmitted from bird to bird by certain species of mosquitoes.

If a mosquito that bit an infected bird then bites a human, that West Nile virus pathogen may infect that person causing West Nile encephalitis.

Another vector-borne disease is eastern equine encephalitis.

Like West Nile virus, this is caused by a virus that is naturally found in songbird populations.

Eastern Equine Encephalitis virus is transmitted from bird to bird by a mosquito species that prefers to bite birds.

However, sometimes another mosquito species that is less picky or a generalist, may feed on an infected bird.

This mosquito may then feed on a human and infect that person and cause illness.

This mosquito species is called a bridge vector, because it moves the pathogen from birds to humans, like a bridge connecting them.

There are many tick-borne or tick transmitted vector-borne diseases.

The most common in the United States is Lyme disease.

The pathogen that causes Lyme disease, a bacterium called borrelia burgdorferi, is maintained in wild animal populations, primarily white-footed mice and chipmunks, although it can be found in other animals like birds.

The vector of this pathogen is the blacklegged tick, also known as the deer tick.

Now, this tick-borne disease has a more complicated cycle than the mosquito-borne diseases.

Ticks have three life stages where they feed on animals, larva, nymph, and adult.

Although a tick does not hatch from the egg infected, the immature tick life stages can feed on animals that may be infected with the Lyme disease pathogen.

Each time they feed, they have an opportunity to become infected with the pathogen, if that host was infected.

That means that there are several life stages of ticks, both nymphs and adults, that can infect people, dogs or horses with the Lyme disease pathogen.

There are many other mosquito and tick-borne pathogens, and there are even more being discovered.

Taking this time to learn more about which vector-borne disease you are at risk from, can help you be prepared to reduce that risk.