Many people think about ticks only when trying to avoid them or after they've been bitten. However, learning more about ticks is essential for preventing tick-borne illnesses, especially if you're frequently in areas where ticks are common.
By understanding tick behavior, you can reduce your risk of contracting diseases they may carry. For example, ticks feed on hosts to grow and progress through different life stages. Some ticks, like black-legged deer that spread Lyme disease, choose different hosts at each stage, while others may use the same host throughout their lives.
This article details the tick life cycle, how they contract diseases, when they can spread them, and how these factors change with the seasons.
The Life Cycle Of Tick
The tick life cycle has four stages:
Eggs
Ticks have a lifespan of two to three years, during which they pass through four stages: egg, larva, nymph, and adult. The life cycle begins with the egg.
Female ticks typically lay thousands of eggs in the spring, often in warm, soft areas like leaf litter. Unlike some parasites, ticks do not lay their eggs directly on a host.
Most ticks pick up diseases by feeding on an infected host. However, in the case of Tick-Borne Relapsing Fever (TBRF), an adult tick can transmit the bacteria to its eggs. This means some ticks are born with TBRF and can spread it to humans from birth.
Larva
After about two weeks to two months, tick eggs hatch into six-legged larvae, typically in the summer.
In the larval stage, ticks usually feed on smaller animals like white-footed mice, raccoons, and squirrels, a process known as a blood meal. If a larval tick feeds on a white-footed mouse, a reservoir host for Lyme disease, it can pick up the bacteria Borrelia burgdorferi. Once infected, the tick can spread Lyme disease throughout its life. The same applies to other diseases ticks may acquire as larvae. Because ticks can spread diseases to various hosts, they are often referred to as "nature's contaminated needle."
After their first blood meal, tick larvae drop to the ground and begin molting into the next life stage.
Nymph
Ticks usually enter the nymph stage between fall and spring, becoming most active when the temperature is above 37°F. Nymphs have eight legs, and their behavior varies based on the weather. In warmer temperatures, they actively search for new hosts, while in colder conditions, they tend to stay in sheltered areas such as under snow or leaf litter. Though less common, ticks can still feed and spread disease during colder months.
There are differences between the life cycles of hard and soft ticks. Soft ticks go through more developmental stages, with two to five nymphal stages.
During the nymph stage, ticks can transmit Lyme disease and other infections. They may also become infected with bacteria for the first time or acquire a second bacterial infection. Nymphs typically feed for four to five days before transitioning to the next life stage.
Adult
Ticks usually become adults in the fall and seek out their third and final host. If they don't find a host before winter, they go dormant until warmer weather returns, usually around February or March, depending on the region.
While some species, like the brown dog tick, feed on the same host throughout life, others prefer different hosts. For example, black-legged (deer) ticks might feed on birds, reptiles, and amphibians as nymphs and switch to larger mammals, including humans, as adults.
A tick's life typically ends if it cannot find a new host. Before dying, a tick will mate, with females laying thousands of eggs before dying and males dying shortly after mating.
Protecting Yourself From Tick-Borne Diseases
Understanding the life cycles of various tick species can help you assess the risk of contracting a tick-borne illness if bitten. Cover your arms and legs when in tick-prone areas to prevent bites, and use insect repellent with DEET or lemon-eucalyptus oil. It's also essential to check your pets, especially dogs, for ticks after outdoor activities like hiking or playing outside.
If a tick bites you or someone you know, consider getting thorough testing from a trusted lab, such as IGeneX. Save the tick and send it for testing to improve the accuracy of the results.
