What are the other Names for this Condition? (Also known as/Synonyms)

• Human Tick Paralysis

What is Tick Paralysis? (Definition/Background Information)

• Tick Paralysis is a medical condition in which the functions of the muscles are affected due to exposure to a neurotoxin, produced by a tick (in the tick’s salivary glands)
• The tick gets attached to the human skin, and the toxin makes its way into the human blood stream through the tick bite and causes the characteristic signs and symptoms
• Ticks that commonly cause the condition are the Rocky Mountain wood tick, the American dog tick, and the Australian paralysis tick, which are generally endemic to certain regions in America, Canada, and Australia
• Tick Paralysis is an acute, ascending, flaccid motor paralysis, meaning that the paralysis starts from the lower body and moves upwards
• The diagnosis of the condition requires a thorough physical exam. Finding the attached tick on the skin is very helpful in arriving at a definitive diagnosis
• The only and key treatment measure is the removal of the tick from the body, with consequent full recovery. If the tick is not located and removed, then Tick Paralysis can be potentially fatal, due to respiratory paralysis

Who gets Tick Paralysis? (Age and Sex Distribution)

• Any individual can be affected by Tick Paralysis, but children under the age of 10, seem to be the most affected population
• There is no gender, racial, or ethnic predilection; however, a higher number of incidences are reported in girls and women due to their longer hair, which conceal the ticks better 
• Tick Paralysis is common throughout the world. Research shows that there may be nearly 60 species of ticks that can cause paralysis in humans. However, it is treated as an endemic disease in certain regions of Australia, North Western USA, and South Western Canada

What are the Risk Factors for Tick Paralysis? (Predisposing Factors)

Following are the risk factors associated with Tick Paralysis:

• Living in tick-infested areas
• Camping trips, outdoor treks to places where the paralytic ticks are found in abundance (particularly in the endemic regions)
• Many farm animals (goats, sheep, and cows) and some pets (dogs, and rarely cats) harbor these ticks, which can easily be transmitted to humans via a direct contact
• Seasonal influence: The risk of Tick Paralysis increases in spring and early summer, when the female ticks move out of hibernation and start looking for hosts

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Tick Paralysis? (Etiology)

Human Tick Paralysis is caused by the exposure to a neurotoxin, which is produced in the salivary glands of certain ticks.

• Tick Paralysis is caused by over 60 species of ticks found all over the world. However, the 3 main ticks associated with the condition are:
  • Rocky mountain wood tick or Dermacentor andersoni
  • American dog tick or Dermacentor variabilis
  • Australian paralysis tick or Ixodes holocyclus  
• The condition occurs when the egg-laden female tick produces a neurotoxin in its salivary gland and passes it on to its host, while feeding on human blood. The tick stays continuously attached to the body part (such as the scalp) and a large quantity of the toxin is produced during the fifth and seventh day of its attachment
• Many farm animals, such as cattle and other animals that graze, and pets, such as dogs, are host to the ticks. Any contact with the tick-infected animal can result in tick bites
• Tick Paralysis is not caused by a pathogenic microorganism. It is the only disease under the category of “tick-borne diseases”, as classified by infectious diseases experts, which is not caused by an infectious agent

What are the Signs and Symptoms of Tick Paralysis?

The symptoms and signs of Tick Paralysis start appearing within 2-7 days after exposure to the tick bite. These include:

• Ataxia (unsteady gait), which is followed by weakness in the lower legs, paralysis of the legs, which then moves upwards to the body (ascending paralysis); to the arms, trunk and head
• Changes in voice due to laryngeal paresis
• Changes in the rhythm, rate, and effort of breathing
• Gagging, grunting, coughing, and vomiting
• Minor sensory symptoms may be present, tendon reflexes are either hypoactive or absent
• Pupillary dilation
• Ophthalmoplegia: Double vision or blurring of vision due to weakness of eye muscles
• Flu-like symptoms such as muscle aches and tiredness

How is Tick Paralysis Diagnosed?

The diagnosis of Tick Paralysis may include:

• Complete evaluation of medical and recent travel history (outdoor visits or activities)
• Finding the embedded tick on the skin on a thorough physical exam
• Usually the tick is found on the scalp and hence, the hair and scalp must be carefully and thoroughly examined
• No other diagnostic test is required to confirm the diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Tick Paralysis?

Tick Paralysis when left untreated can lead to the following complications:

• Respiratory failure
• Convulsions and seizures

Death can result on account of the complications, if diagnosis and supportive treatment is delayed.

How is Tick Paralysis Treated?

• Removing the tick from the skin is the only required treatment for Tick Paralysis; this improves the symptoms almost immediately
• Supportive treatment may be provided for any associated signs and symptoms
• If a respiratory difficulty is observed, then respiratory support using ventilators may be beneficial

How can Tick Paralysis be Prevented?

Preventive measures to be adopted for Tick Paralysis may include:

• Use of insect repellents in and around the house will help keep away the ticks
• Wearing protective clothing while moving outdoors, in areas where you can be exposed to ticks
• Careful and thorough examination of the skin once you get back from the outdoors; remove the tick if it is found
• Avoiding exposure to areas with overgrown bushes and trees
• Wearing light-colored clothes will help to see the ticks, if they get attached to the clothes
• Wearing long pants and toe-covering shoes will protect the skin from tick bites
• Tick repellents containing DEET may be applied on the clothes or skin
• Applying permethrin on the clothes is a very effective way of preventing the tick bites

What is the Prognosis of Tick Paralysis? (Outcomes/Resolutions)

• The prognosis of Tick Paralysis is excellent, once the tick is found and removed
• If the tick is not removed, then the condition may be potentially fatal

Additional and Relevant Useful Information for Tick Paralysis:

• The Ixodes holocyclus is the most dangerous tick to cause Tick Paralysis. It is found in the eastern coast of Australia. The tick attacks other animals (livestock, dogs, and cats) too, besides humans
• In USA, mostly dogs suffer from paralysis as a result of tick bites, primarily from the American dog tick and the Rocky Mountain wood tick
• Tick Paralysis in north America usually occurs from April to June, when the adult Dermacentor tick comes out of hibernation, in search of hosts
• Researchers have been making continuous efforts to identify the exact structure of the neurotoxin released by the salivary glands of the ticks; but, it still remains elusive