Why Tick-Borne Diseases Are a Public Health Focus in Delaware

Delaware may be small, but its tick problem is not.

A 2025 article in the Journal of Medical Entomology makes that clear. The study, titled “Ticks of Delaware revisited: an updated checklist of hard ticks and first records of soft ticks in the First State,” reviewed scientific literature, museum collections, archived tick specimens, and Delaware’s ongoing tick surveillance program, which began in 2019. The researchers reported 15 established hard tick species in Delaware, along with additional hard tick and soft tick species that are not yet confirmed as established.

That matters because tick-borne diseases are not just a seasonal nuisance. In Delaware, they are a real public health concern.

According to the study, Delaware carries an “outsize share” of the national tick-associated disease burden. The article notes that Delaware ranks among the top 10 states for incidence rates of Lyme disease, ehrlichiosis, and spotted fever rickettsioses, and is also considered a high-incidence state for alpha-gal syndrome.

For residents, visitors, pet owners, hunters, hikers, gardeners, and families spending time outdoors, this is the takeaway: ticks in Delaware deserve serious attention.

Delaware’s Tick Problem Has Changed Over Time

More than 75 years ago, Delaware’s first tick checklist considered the American dog tick the only significant tick threat to humans in the state. That is no longer the case.

The updated research says that the blacklegged tick and lone star tick have now surpassed the American dog tick in medical importance. The blacklegged tick, also known as the deer tick, can transmit the agents that cause Lyme disease, babesiosis, anaplasmosis, and other illnesses. The lone star tick is linked to ehrlichiosis, tularemia, and alpha-gal syndrome.

This shift is important. It means Delaware’s tick risk is not limited to one species or one disease.

The Tick Species Delaware Residents Should Know

The article highlights several ticks with public health or veterinary importance in Delaware.

Lone Star Tick

The lone star tick is described as the most commonly encountered tick species in Delaware. It is abundant statewide, with higher densities in Kent and Sussex Counties than in New Castle County. The study also notes that lone star tick larvae peak between July and August, nymphs between May and July, and adults between April and June.

This species is considered aggressive, and all active life stages can bite humans. It is medically significant because it can carry agents associated with ehrlichiosis and tularemia, and it is strongly associated with alpha-gal syndrome, also known as mammalian meat allergy.

Blacklegged Tick / Deer Tick

The blacklegged tick is established statewide in all three Delaware counties. The article describes it as arguably the most medically important tick species in the United States because it can transmit at least seven pathogens that cause disease in humans. These include the agents of Lyme disease, anaplasmosis, babesiosis, Powassan virus disease, ehrlichiosis, and tick-borne relapsing fever.

For Delaware, this is one of the most important ticks to understand because it connects directly to several diseases that affect people in the Mid-Atlantic region.

American Dog Tick

The American dog tick remains important. The article identifies it as one of the principal ticks of public health importance in the United States because it can vector agents associated with Rocky Mountain spotted fever, tularemia, Q fever, and anaplasmosis.

Even though other ticks have grown in medical importance, this species is still part of the larger tick-borne disease picture in Delaware.

Gulf Coast Tick

The Gulf Coast tick is another species to watch. The article says it became established in Kent County by 2013 and in all three Delaware counties by 2019, with the highest numbers collected in Sussex County. It is a vector of Rickettsia parkeri, the agent of Tidewater spotted fever, and the first record of a Gulf Coast tick infected with Rickettsia parkeri in Delaware came from a specimen collected at Bombay Hook National Wildlife Refuge in 2012.

Asian Longhorned Tick

The Asian longhorned tick was first detected in the United States in 2017 and first detected in Delaware in 2019. The article states that it is now established statewide. While its public health impact in North America has been limited so far, the study identifies it as a species of veterinary concern because it can transmit Theileria orientalis, a parasite that causes theileriosis in cattle.

Why This Is a Public Health Issue

Tick-borne diseases are a public health focus in Delaware because the state has several medically important tick species, documented disease burden, and conditions that allow people and ticks to overlap.

The study’s authors specifically say their objective was to update the list of Delaware tick species and assess their risk to public health. They also note that understanding which tick species occur in an area, when people are most likely to encounter them, and which hosts they feed on is an important step in evaluating risks to humans, livestock, companion animals, and wildlife.

That is the heart of the issue. Public health is not only about treating illness after it happens. It is also about knowing where risks exist, which species are spreading, and how residents can reduce exposure before a bite occurs.

Tick Awareness Is Still Too Low

One of the most important points in the article is that tick literacy and public concern for tick-associated diseases remain low in Delaware.

That is a problem because prevention depends on awareness.

People need to know that ticks can be found in wooded, brushy, grassy, and even residential areas. They need to know that different tick species can carry or cause different health issues. They also need to understand that checking for ticks after outdoor activity is not just a good habit. In Delaware, it is a practical health step.

The Bottom Line

Delaware’s tick issue is bigger than many people realize.

The state has 15 established hard tick species, several medically important ticks, and a documented burden of tick-associated diseases that places it among the higher-risk states for several conditions. The blacklegged tick, lone star tick, American dog tick, Gulf Coast tick, and Asian longhorned tick all play a role in why tick surveillance and public education matter.

The main message is simple: tick-borne diseases are a public health focus in Delaware because the risk is real, local, and ongoing.

For residents and visitors, the best response is not panic. It is prevention, awareness, and quick action after possible exposure.

Check yourself. Check your pets. Know the common ticks. Watch for symptoms. And take Delaware’s tick season seriously.

Source: https://academic.oup.com/jme/article/62/4/851/8108234