Ticks are small, parasitic arthropods that feed on the blood of mammals, birds, and reptiles. They are vectors of disease, causing a variety of illnesses in humans and animals. Ticks are found in all parts of the world except Antarctica. There are over 850 species of ticks; the three most common types in the United States are the deer tick (Ixodes scapularis), dog tick (Dermacentor variabilis), and lone star tick (Amblyomma americanum).
Ticks go through four stages in their life cycle: egg, larva, nymph, and adult. The eggs hatch into six-legged larvae which must then find a host to feed on before they can molt into eight-legged nymphs. Nymphs and adults both require a blood meal before they can mate and lay eggs. Females lay anywhere from 2,000 to 18,000 eggs at a time; depending on the species, it can take anywhere from two weeks to two years for them to hatch.
While feeding, ticks insert their mouthparts into the skin of their host and release saliva that contains anticoagulants and other substances that prevent tissue damage and keep the host’s blood flowing. This process can take several days; during this time, ticks can swell to many times their original size as they gorge themselves on blood. If left unchecked, ticks can cause anemia or even death in extreme cases. In addition to being a nuisance, ticks can transmit diseases like Lyme disease, Rocky Mountain spotted fever, babesiosis, tularemia , ehrlichiosis , anaplasmosis , encephalitis , Colorado tick fever , Powassan virus infection , African swine fever , Crimean–Congo hemorrhagic fever , Kyasanur Forest disease virus infection among others via their bites . Lyme disease is caused by bacteria belonging to the genus Borrelia ; it is the most common vector-borne illness in North America . Symptoms include fever , headache , fatigue , muscle pains , joint pain s rashes . If left untreated Lyme disease can lead to serious complications affecting various organs including the heart and nervous system . Lyme disease is diagnosed based on symptoms clinical history exposure risk factors laboratory test results . Treatment typically involves antibiotic therapy . Prevention measures include prompt removal of attached ticks using tweezers avoiding wooded areas where deer mice live using repellents containing DEET wearing long pants tucked into socks when hiking spraying clothes with permethrin .
Tick bites usually occur unnoticed because most people do not feel pain when bitten however redness inflammation swelling sometimes develops around site within 24–48 hours after attachment occurs if person has allergic reaction local reactions may last several days longer general feeling ill may also develop these more systemic reactions rare but could indicate beginning onset of Lyme disease or another disorder transmitted by tick should be evaluated promptly by healthcare provider particularly if accompanied by high fever chills muscle aches shortness breath nausea vomiting rash weakness paralysis