All about ticks

Ticks are spider-like parasitic bugs that belong to the spider family. They are arachnids and not insects. There are many different species of ticks and many carry bacteria, viruses and other pathogens. Ticks live of the blood of vertebrate animals and sometimes humans. Because ticks can transmit various diseases they are therefore also called vectors. In addition to mosquitoes, ticks are the main distributors of pathogens.

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Life stages

Ticks generally have three life stages: larvae, nymphs and adults. During each stage, the tick must take a blood meal after which they enter a dormant period and enter the next stage.

Larva stage
When the tick creeps from the egg it is called a larva. At the larval stage, the tick has 6 legs instead of 8. The larvae crawl, after having come out of the egg, on grass or a plant. When a host comes by they cling to it and find a place on that host to suck blood. After the blood meal they drop off. Larvae are not infected with Lyme Borrelia. Unlike the Borrelia that causes Lyme disease, larvae can be infected with Borrelia Miyamotoi, a Relapsing Fever Borrelia, which can be transferred from adult ticks to the larvae.              

Nymph stage
After the blood meal, the larva enters the second stage and become a nymph tick. It re-searches for a host, which repeats the process. The nymph creeps on grass or a plant and waits until a host walks along to cling to it. Most infections with Lyme disease are caused by the bite of a nymph during spring or summer. If the larva has fed on an infected host, the nymph is infected and can transmit the disease during a blood meal in subsequent stages.

Adult stage
After the blood meal at the nymph stage, the tick reaches maturity. Males do not feed at this stage and are actively seeking female ticks for reproduction. The female produces thousands of eggs after her blood meal before she dies. Out of these eggs come from larvae, which repeats the cycle. 

Lifecycle

The lifecycle of a tick takes about 2 years. In spring, adult females lay eggs. The larvae feed on birds, mice and other small rodents during spring and summer.

In the fall they reach the nymph stage. During the fall and winter the nymphs become inactive. During the spring these nymphs become active again, and now feed more often on larger animals such as dogs, deer and people during spring and summer.

During autumn they enter the adult stage and the females will look for a blood meal to lay eggs in the spring.

Ticks and pathogens

Ticks have a mouth piece that can penetrate the skin of their host. In the saliva of the tick are different substances that inhibit the immune system, suppress pain and prevent blood from clotting. As a result, the bite is painless and no inflammatory reaction occurs.

Attachment

The feeding takes about 72 to 96 hours to complete. During the feeding continuous saliva must be injected to keep the blood flowing. On the one hand the tick sucks blood and on the other hand the tick also injects saliva. Ticks are so dangerous, compared to mosquitoes for example, because they are attached much longer. In addition, the bite is completely painless and ticks are tiny and easily overlooked.

Transmission

The tick empties its salivary glands and this is how bacteria and other pathogens are transmitted. The Borrelia bacteria generally require time to be transmitted. They need to travel from the mid-gut of the tick to the salivary glands. The risk of infection with Lyme disease during the first 24 hours is generally considered low according to the CDC.

Some doctors and patient organizations feel that this gives a false sense of security. In some research studies nymph ticks transmit the disease within the first 24 hours. Not all patients recall a tick bite or rash.

For co-infections it is not known how much time is needed for transmission. There are studies that suggest that some infections can be transmitted in the first minutes of attachment.

Remove a tick

It is important to remove a tick as quickly as possible to minimize the risk of infection. You can remove a tick with fine tweezers. It is important to not put lubricants on the attached tick such as oil or alcohol. Alcohol or oil can irritate the tick and this can cause the tick to empty its stomach contents. This increases the risk of infection considerably.

– Remove the tick with good technique (without smudging the tick)
– Throw the tick into the toilet
– Disinfect the wound after the tick has been removed with an alcohol solution
– Wash your hands with an antibacterial soap

After removing the tick keep an eye on the bite. If a red rash develops or you get flu-like within 3 months after the tick bite consult a doctor.

 

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