Ticks were once most active between March and October, but due to a consistent increase in warm weather spurred by climate change, varying tick species are now active year round in Connecticut. 

The state is home to around 15 species of ticks, and five of them impose significant public health risks as they can transmit several pathogens, like bacteria or viruses, that cause diseases, according to Dr. Goudarz Molaei, a research scientist at the Connecticut Agricultural Experiment Station, who began studying ticks in 2015.

Black-legged “deer” ticks and American dog ticks are the most common species in the state, but there has been a recent prevalence of the invasive lone star tick, Gulf Coast ticks and longhorned ticks. 

Here’s what to know about the critters and how to stay safe.

What tick-trasmitted pathogens are common? 

Lyme disease, spread by deer ticks, is most common in the Northeast. Other transmittable illnesses spread by deer tick bites include babesiosis, a disease in which parasites infect red blood cells, and anaplasmosis, which is linked to a bacteria and has symptoms as varied as high fevers and headaches on one end of the spectrum and respiratory and organ failure on the other. Another transmittable illness, Rocky Mountain spotted fever, which is a bacterial infection, can be spread by dog ticks. 

According to a Stamford Health article, the number of lone star ticks collected in the state jumped to 2,570 in 2025 from 72 the previous year. 

They are responsible for transmitting pathogens that cause ehrlichiosis, which induces high fever, severe headaches and chills, and alpha-gal syndrome, which induces a red meat and mammal-product allergy and is spread by lone star ticks through their saliva. Allergy symptoms can begin within three to six hours of consuming the product.

“Connecticut is probably the most northern state with an established population of lone star ticks,” Molaei said. “We suspect that other tick species are also involved [in the spread of alpha-gal.]” 

The number of longhorned ticks, which can also transmit pathogens for ehrlichiosis, are on the rise too. This species of tick is parthenogenetic, or capable of reproducing without relying on males. 

In 2021, researchers found established populations of this species in Bridgeport and Stratford. Since then, it has spread across Fairfield, New Haven and New London counties. 

How does a tick pick up transmittable diseases? 

Within a two to three year cycle, ticks lay eggs, which develop into larvae before becoming nymphs and then full-grown adult ticks.

They become infected with diseased agents based on the animals they feed on. However, its ability to transmit a pathogen depends on what type of tick it is. 

Deer ticks, for example, have to feed on various hosts to develop into the next stage of their life cycle. 

They’re usually born pathogen-free, but various feedings throughout their life cycle means it’s another opportunity to pick up a pathogen. 

“If they [larvae] bite rodents, pick up the disease agent, digest the blood, they would then develop into nymphs,” Molaei said. “If the blood that they have taken from rodents is infected, they are able to pass it onto nymphs.” 

According to Molaei, most adult deer ticks are probably infected. 

“If you go out and collect ticks, chances are, 50% of them could be infected,” he said. 

How can I stay safe? 

According to Molaei, prevention is key to steering clear of tick-transmitted pathogens. 

Ticks are surveyed in the state through both active surveillance, where researchers go outdoors and collect ticks from 40 sites on a daily basis, and passive surveillance, when the public submits ticks to their local health department or ACES for testing.

Researchers used to believe that ticks only frequented spaces with tall grass, but now they’re also found by beaches and sparsely vegetated areas. Molaei recommends wearing light colored clothing, tucking pants into socks, spraying clothing with chemicals like permethrin and conducting tick checks after outdoor excursions. 

“People have to be aware of their surroundings pretty much everywhere,” Molaei said. “Tick checks are not only important for humans but also important for their pet animals.”