The prevalence of ticks in Missouri makes understanding their seasonal activity a public health concern for anyone spending time outdoors. These small arachnids are capable of transmitting various disease-causing pathogens to humans and pets. Because the risk of exposure is widespread across the state, knowing when ticks are most active is the first step toward effective prevention. This article focuses on the activity periods, identification, and disease risks associated with ticks in Missouri.
The Seasonal Cycle of Ticks in Missouri
The concept of a “tick season” in Missouri spans from early spring to late fall, but activity is not strictly confined to these months. Ticks can become active any time the ground temperature rises above freezing, meaning warm winter days can still pose a risk. The main window of activity typically begins in March and can extend into November, with peak activity occurring during the warmer, more humid months.
Peak activity varies depending on the species and its life stage, creating overlapping periods of risk throughout the year. The Lone Star Tick is most numerous from April through July, while the American Dog Tick is highly active from mid-April through early September. The Blacklegged Tick is more common in spring and fall, though adults may be searching for a host any time winter temperatures are above 32°F. Most tick-borne disease cases are reported during May, June, and July, which coincides with peak outdoor activity.
Identifying Common Ticks in Missouri
Missouri is home to three common hard ticks that are responsible for the majority of human bites and disease transmission.
Lone Star Tick
The adult female Lone Star Tick is easily identified by a distinct, silvery-white or iridescent spot on her back, giving the species its name. Males do not have the single spot but may have mottled white markings around the edge of their body. This tick is found statewide, often in woodlands, brushy areas, and grassy fields where it seeks a host.
American Dog Tick
The American Dog Tick, sometimes called the wood tick, is larger than other common species. Adults are recognizable by the ornate brown body with grayish-white or silvery markings on their back. These ticks are common across the state, particularly in grassy habitats along trails and in open fields.
Blacklegged Tick
The Blacklegged Tick, also known as the Deer Tick, is noticeably smaller, often described as being the size of a sesame seed. This species has a reddish-orange body and black scutum (shield), with legs and an upper body that appear black.
Major Tick-Borne Diseases in Missouri
Ticks in Missouri transmit several diseases, with Rocky Mountain Spotted Fever (RMSF) being the most frequently reported illness in the state. RMSF is prevalent in Missouri and is transmitted by both the American Dog Tick and the Lone Star Tick. Early symptoms include a sudden high fever, severe headache, and muscle aches, with a rash often developing a few days later.
Ehrlichiosis is another common illness in Missouri, with the Lone Star Tick serving as the primary vector. This disease presents with non-specific, flu-like symptoms such as fever, chills, fatigue, and headache. Both RMSF and Ehrlichiosis can become severe without prompt antibiotic treatment. A bite from the Lone Star Tick is also associated with Alpha-gal syndrome, a condition that causes a severe allergic reaction to consuming red meat.
Immediate Steps for Tick Prevention and Removal
Protecting yourself begins with prevention measures before and after outdoor activity. Wearing light-colored clothing makes it easier to spot ticks, and treating clothing and gear with a product containing permethrin offers added protection. On exposed skin, use an EPA-approved repellent that contains DEET or picaridin. After returning inside, showering soon after can help dislodge unattached ticks, and a thorough body check should be performed, paying close attention to areas like the scalp, armpits, and groin.
If a tick is found attached to the skin, removing it correctly minimizes the risk of disease transmission. Use fine-tipped tweezers to grasp the tick as close to the skin’s surface as possible, ideally near the head or mouthparts. Pull the tick upward with a steady, even pressure without twisting or jerking, which could cause the mouthparts to break off. Once removed, the bite area and your hands should be thoroughly cleaned with soap and water or rubbing alcohol.