Summary about Disease
Wood tick paralysis is a rare, acute, ascending flaccid paralysis caused by a neurotoxin present in the saliva of certain species of female ticks, most commonly the Rocky Mountain wood tick ( Dermacentor andersoni ) and the American dog tick ( *Dermacentor variabilis* ). The paralysis resolves rapidly after the tick is removed.
Symptoms
The hallmark symptom is ascending flaccid paralysis, meaning weakness starts in the legs and gradually progresses upwards towards the trunk, arms, and potentially affecting respiratory muscles. Other symptoms may include:
Fatigue
Numbness
Difficulty walking or speaking
Muscle weakness
Loss of coordination
In severe cases, respiratory failure
Causes
The cause is a neurotoxin secreted in the saliva of female ticks, particularly Dermacentor andersoni and *Dermacentor variabilis*, during feeding. The toxin interferes with nerve transmission, specifically blocking the release of acetylcholine at the neuromuscular junction, leading to paralysis.
Medicine Used
There is no specific medicine to treat wood tick paralysis. The primary treatment is prompt removal of the tick. Recovery typically follows within hours to days after tick removal. Supportive care, such as respiratory support (e.g., mechanical ventilation), may be needed in severe cases until the toxin is cleared.
Is Communicable
No, wood tick paralysis is not communicable. It is not contagious and cannot be spread from person to person. It is caused solely by the tick bite and the neurotoxin it injects.
Precautions
Prevention focuses on avoiding tick bites:
Wear protective clothing (long sleeves, long pants tucked into socks or boots) when in tick-infested areas.
Use insect repellents containing DEET on skin and clothing.
Perform thorough tick checks on yourself, children, and pets after spending time outdoors.
Remove ticks promptly and carefully using fine-tipped tweezers, grasping the tick as close to the skin as possible and pulling straight out with steady pressure.
Shower soon after being outdoors to find and remove ticks easier
How long does an outbreak last?
Wood tick paralysis is not considered an "outbreak" in the traditional sense of a communicable disease. Cases occur sporadically when individuals are bitten by toxin-producing ticks. The duration of paralysis lasts until the tick is removed and the neurotoxin is cleared from the body. This can be anywhere from hours to a few days.
How is it diagnosed?
Diagnosis is primarily clinical, based on the characteristic ascending paralysis and a history of potential tick exposure. A thorough physical exam is performed to search for the tick. Other tests may be performed to rule out other causes of paralysis, but they are generally normal in wood tick paralysis. The key is the rapid improvement after tick removal.
Timeline of Symptoms
The timeline can vary:
Tick Attachment: The tick needs to be attached for several days (typically 4-7 days) to secrete enough toxin to cause paralysis.
Initial Symptoms: Early symptoms may include fatigue, numbness, or slight unsteadiness.
Progressive Paralysis: Weakness begins in the legs and ascends over hours to days.
Respiratory Involvement (Severe Cases): Respiratory distress can develop rapidly in severe cases.
Recovery: Following tick removal, improvement usually begins within hours, with full recovery within days.
Important Considerations
Wood tick paralysis can be life-threatening if it affects respiratory muscles, requiring immediate medical attention.
Infants and young children are particularly vulnerable due to their smaller size and potential difficulty in communicating symptoms.
Misdiagnosis is possible, so it is crucial to consider tick paralysis in any patient with ascending paralysis, especially in areas where ticks are prevalent.
Prevention is key.
Even if a tick is removed, seek medical attention if symptoms of paralysis develop.