Ixodid ticks are blood-sucking parasites that can transmit the causative agents of tick-borne encephalitis and borreliosis (Lyme disease). Understanding their sizes, coloration, and developmental stages is often necessary at the moment when the tick has already been removed from the skin.
What are ixodid ticks
Ixodid ticks (Ixodidae) are a family in the order Ixodida: over 650 species in approximately 15 genera. They are not insects — adult specimens have eight legs, are related to spiders, and feed on the blood of humans and warm-blooded animals. They are found worldwide, even in the Arctic and Antarctic. They live in forests, tall grass, leaf litter, and shrubs, sometimes in urban parks. They do not jump or fly: they cling to whoever passes by.
What species of ticks exist
The family includes the genera Amblyomma, Dermacentor, Haemaphysalis, Hyalomma, Rhipicephalus, and Ixodes. Most bites in Russia are associated with two species of the genus Ixodes — the castor bean tick (Ixodes ricinus) and the taiga tick (Ixodes persulcatus); together with certain Dermacentor species, they transmit tick-borne encephalitis and borreliosis. Allergy to mammalian meat was first described in 2007; cases have been registered in 17 countries, and among the confirmed culprits are Ixodes ricinus and Amblyomma americanum.
What an ixodid tick looks like: size and color
An unfed female is 3–4 mm long, a male up to 2.5 mm. An engorged female grows to 10 mm, and its color changes to light gray. Coloration varies among species: from light to reddish-brown and dark brown; some specimens are so small that they are hard to notice. The dorsal shield covers the entire body in the male and about one third in the female.
Tick larva and nymph: developmental stages
The female lays up to 17 thousand eggs in the soil, and only a few survive to the adult stage. The larva feeds once, usually on small mammals — rodents, insectivores, mustelids. An engorged larva falls to the ground and turns into a nymph; after feeding and molting, the nymph becomes an adult. Adult females feed once, mainly on cattle. How often infection is transmitted specifically by larvae is not specified in the available materials; the general rule is that not every tick is infected, and the pathogen is transmitted once the tick has begun to suck blood.
The tick's hypostome and how a tick attaches
The tick attaches to the skin and feeds on blood for several days, then drops off. The bite is not always painful, so it is often found by chance. The hypostome (mouthparts) is embedded in the skin, and if removal is unsuccessful, part of the mouthparts may remain in it. The earlier the tick is removed, before it becomes engorged with blood, the lower the risk of infection.
Why ticks are dangerous and when to see a doctor
The consequences depend on whether the tick was infected. The following are transmitted by a bite:
- Lyme disease (borreliosis);
- allergy to red meat (alpha-gal);
- babesiosis;
- ehrlichiosis;
- Rocky Mountain spotted fever.
An early sign of Lyme disease is a round or oval redness around the bite: it appears up to 3 months after the bite, more often after 1–4 weeks, lasts several weeks, and is usually not hot and does not itch. On white skin it is pink, red, or purple; on brown and black skin it is harder to see — it may resemble a bruise. After days or weeks, high fever, chills, headache, muscle and joint pain, and fatigue are possible; later — joint pain and swelling, and problems with the nerves, heart, and memory. The diagnosis is made based on symptoms and information about the bite; two types of blood tests are not always accurate in the early stages, so if symptoms persist after a negative result, the test is repeated. See a doctor if within the last 3 months there was a bite or a stay in an area with infected ticks and flu-like symptoms or a round or oval redness have appeared.
A tick bite by itself is not a reason to call an ambulance; 103/112 — if signs of stroke or heart attack appear or there is a threat to life.
This material is for reference: it helps identify a tick but does not replace a doctor's consultation.
Sources
Update history
Reader reviews
No reviews yet — tell us whether this article was helpful.
Leave a review
This content is for reference and does not replace a doctor's consultation. Medical disclaimer