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  • Devon James

How Ticks Transmit Diseases

Updated: Apr 8

Ticks can carry and transmit up to 18 different pathogens. Knowledge is power and understanding how ticks transmit these diseases and what to look out for is paramount.

Once its mouth piece is inserted, the tick alternates between injecting saliva and ingesting blood.

Ticks have been around much longer than the human race. In fact, the oldest preserved tick was discovered encased in amber, attached to a prehistoric bird feather. It dates to nearly 90 million years old (from the Cretaceous Period).

The ticks found in North America can carry and potentially transmit as many as 18 different pathogens.


How Transmission Works

After the tick has climbed aboard an unsuspecting host, they crawl around until they find a suitable feeding spot. They then cut through the skin with two sharp pincer-like structures of the mouthpiece, and insert a barbed, tube-like appendage, through which they consume blood. In a brilliant evolutionary twist, tick saliva contains a substance that acts like cement, bonding the tick to its’ host, giving it the best chance possible to succeed in its feeding mission. The saliva of some ticks also contains an anesthetic property, making the bite painless, adding further to their imperceptibility.


Once its mouth piece is inserted, the tick alternates between injecting saliva and ingesting blood. When the first of your blood enters the tick’s gut, it signals the bacteria to begin reproducing, and eventually to travel up into the tick’s salivary glands. Once the bacteria are there, they can enter your body via the tick’s saliva.

In order for an infection to take hold, a sufficient number of bacteria have to enter the host’s body. If only a few bacteria make it in, then the human or animal immune system may be able to fight them off and prevent an infection. Hence, it is very important to do tick checks and remove them as soon as possible.

Most people are infected through the bites of immature ticks called nymphs. Because they are so tiny, (less than 2 mm) they are difficult to see and easily missed when doing tick checks.

Adult ticks can also transmit Lyme disease bacteria. They are much larger and are more likely to be discovered and removed.


The good news is that soft ticks have less contact with humans as they tend to live in rodent burrows. If a human does get bitten it is usually associated with sleeping in rustic cabins in mountainous areas where there is an infestation of rodents.

Transmission Times

Transmission time between ticks and their victim varies depending on the type of pathogen the tick is carrying.


Lyme Disease

Lyme disease is caused by bacteria called Borrelia Burgdorferi, which is spread through the bite of blacklegged ticks, and anecdotally said to be transmitted by the wood tick.

Lyme disease is very tricky to diagnose because its symptoms mimic so many other types of illnesses and diseases. And on top of that, many people don’t even know they have been bitten and won’t exhibit any signs of infection until months or even years later.


The spirochete Borrelia burgdorferi is a tick-borne bacterial parasite.

A recent study has shown that Borrelia burgdorferi spreads throughout the body by crawling along the inside wall of blood vessels.

-Biomechanics of Borrelia burgdorferi Vascular Interactions


Symptoms

If you are bitten and are lucky enough to start to exhibit signs right away, here are some of the signs to recognize:

Stage 1: Early localized Lyme disease (1 to 4 weeks)

Early localized Lyme disease develops days to weeks after you become infected. You may have:

  • An expanding, circular red rash (erythema migrans) aka bullseye rash.

  • Flu-like symptoms, with or without the rash. The symptoms include:

  • Lack of energy.

  • Headache and stiff neck.

  • Fever and chills.

  • Muscle and joint pain.

  • Swollen lymph nodes.

In some cases of Lyme disease, the person doesn't notice any symptoms during this stage.

The typical Bullseye Rash only appears in






Stage 2: Early disseminated infection (1 to 4 months)

If Lyme disease isn't found and treated while early symptoms are present, or if you don't have early symptoms that trigger the need for treatment, the infection may affect the skin, joints, nervous system, and heart within weeks to months after the initial infection.

Symptoms may include:

  • An expanding, circular rash at the site of the bite. More rashes may appear on other parts of your body as the infection spreads.

  • Pain, weakness, or numbness in the arms or legs.

  • Not being able to use the muscles of the face (bell's palsy).

  • Headaches or fainting that continues to happen.

  • Poor memory and reduced ability to concentrate.

  • Conjunctivitis (pink eye) or sometimes damage to deep tissue in the eyes.

  • Brief episodes of pain, redness, and swelling in one or more large joints—most often the knee. Joint problems are common.

  • Occasional rapid heartbeats (palpitations) or, in rare cases, serious heart problems.

Late persistent Lyme disease

If Lyme disease isn't promptly or effectively treated, damage to the joints, nerves, and brain may develop months or years after you become infected. It is the last and often the most serious stage of the disease.

Symptoms at this stage may include:

  • Arthritis that most often affects the knee. A small number of people eventually get chronic Lyme arthritis, which causes recurring episodes of swelling, redness, and fluid buildup in one or more joints that last up to 6 months at a time.

  • Numbness and tingling in the hands, feet, or back.

  • Feeling very tired.

  • Not being able to control the muscles of the face.

  • Problems with memory, mood, or sleep, and sometimes problems speaking.

  • Heart problems, which are rare but can occur months to even years after you are bitten by an infected tick. The most serious heart problems—such as inflammation of the structures surrounding the heart (pericarditis)—usually resolve without any lifelong damage. Unfortunately, heart problems can be the first sign of Lyme disease in a small number of people who didn't have early symptoms.

Stage 2 and stage 3 symptoms may be the first signs of Lyme disease in people who didn't have a rash or other symptoms of early infection. - My Health Alberta Network


Transmission

Transmission time has been a much debated topic amongst the general population who are concerned about or have contracted lyme or other tick related diseases in the past. According to the CDC, ticks need to be attached for 36 to 48 hours before they can transmit the Lyme Pathogen (Borellia Burgdorferi).


A study conducted and published in the journal of Ticks and Tickborne Diseases by Lars Eisen confirmed that it most likely takes more than 24 hours and closer to 48 hours for the tick to successfully transmit the Lyme Pathogen to a human.

Borrelia Burgdorferi


Currently there is no Lyme Vaccine on the market, however, a biotech company called Valneva is working on one in partnership with Pfizer.

If that puts your mind at ease, don’t let your guard down. There are many other vector borne diseases that ticks carry that can be transmitted in a much shorter period of time.


Powassan Virus

The Powassan virus is a flavivirus (a virus rather than a bacterium) and is related to the West Nile virus that is spread by mosquitoes. The Powassan virus is named for the small town of Powassan near North Bay Ontario where it was identified in 1958 in a young boy who eventually died from it. It is very rare as only 150 cases have been reported globally with 21 cases in Canada. However, cases have increased in recent years. - “Lyme Disease in Canada” Brian Owens.

Powassan virus particles.

Transmission

This virus is transmitted by the blacklegged tick, the squirrel tick and the groundhog tick. The potentially deadly Powassan virus can be transmitted from a tick to a person in as little as 15 minutes.


Symptoms

According to the CDC, “many people infected with Powassan virus do not have symptoms. For those who have them, initial symptoms can include:

  • Fever

  • Headache

  • Vomiting

  • Weakness

Powassan virus can cause severe disease, including infections of the brain (encephalitis) or the membranes that surround the brain and spinal cord (meningitis). Symptoms of severe disease can include:

  • Confusion

  • Loss of coordination

  • Difficulty speaking

  • Seizures

10% of the encephalitis cases are fatal, and half of the survivors have permanent neurological damage.*

This virus is currently found in Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia and PEI.


Rocky Mountain Spotted Fever

Another tick borne disease that is quick to transmit is Rocky Mountain Spotted Fever (RMSF).

RMSF is considered the most serious tick-borne illness as it can be rapidly fatal if not treated within the first 5 days of symptoms.

Signs and Symptoms

Early (1–4 Days)

  • High fever

  • Severe headache

  • Malaise

  • Myalgia

  • Edema around eyes and on the back of hands

  • Gastrointestinal symptoms (nausea, vomiting, anorexia)

Late (5 Days and Beyond)

  • Altered mental status, coma, cerebral edema

  • Respiratory compromise (pulmonary edema, ARDS)

  • Necrosis, requiring amputation

  • Multiorgan system damage (CNS, renal failure)

Transmission

Estimates vary about how long it takes for a tick to transmit this disease, but the CDC advises that it could be transmitted in as little as 2 hours. RMSF can be transmitted by the Rocky Mountain Wood Tick and the Brown Dog Tick.


Tick-Borne Relapsing Fever

Another disease that can be quickly transmitted by ticks is called Tick-Borne Relapsing Fever, which is caused by another type of Borrelia bacteria, distantly related to the Borrelia that cause Lyme.

Transmission

Tick-borne relapsing fever is transmitted by soft (shelled) ticks. These soft shelled ticks only feed for a few minutes, usually less than half an hour, according to the CDC and can transmit the relapsing fever bacteria in this time. The infection normally shows up as repeated episodes of fever, along with headache, muscle and joint aches, and nausea.

Although they can bite people, it is rare as Soft ticks are generally found in animal burrows, dens, caves or broken-down dwellings such as huts, cabins or sheds.


Takeaways:

  • Always do your tick checks not just when you get home but if you are taking a break from a hike, do a quick tick check.

  • Remove the tick as soon as possible in order to decrease the likelihood of infection.

  • Ticks can transmit diseases anywhere from a few minutes to 36 hours. It’s important to be diligent and always have the right tools on your person if headed into tick territory.

  • Remove the tick properly to reduce the chance of infection (find the proper technique here)

It cannot be stressed enough - prevention is the key to avoiding tick bites and their associated diseases. When venturing into the great outdoors (or your own backyard or favourite park) always use an effective, reliable tick repellent, bring a tick remover with you, and always remember to do your tick checks.

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