Tick Paralysis

What is Tick Paralysis?

Tick paralysis is a potentially fatal disease of the nervous system that is caused by the Ixodes holocyclus tick, commonly referred to as a "paralysis tick". The saliva of paralysis ticks contains a toxin that is injected into the blood of the animal that the tick is feeding on. The toxin interferes with normal function of the nervous system, resulting in muscle weakness and paralysis. Not all animals are affected to the same degree, but commonly just one adult tick can cause severe disease in a dog or cat that can be fatal if not treated promptly and effectively.

What are the risks?

Paralysis ticks are found along the eastern coast of Australia, and in areas with thick bushland. Ticks can be a problem year-round in the north, but generally there is a seasonal distribution of disease in more southern areas, with the period of greatest risk from spring to early autumn.

What are the clinical signs?

Signs generally take 4-9 days to develop after the attachment of a tick, and are initially gradual in onset, but once evident can progress rapidly. Signs to look out for include:

• Weakness or unsteadiness, progressing to paralysis - often first noticed in the hindlimbs
• Regurgitation
• Difficulty breathing or noises during respiration
• A change in the voice/bark

Inability to find a tick on the animal does not rule out tick paralysis. As mentioned, just one tick is enough to cause disease, and it may be only a few mm diameter, so can easily be missed. Additionally, disease can occur even after detachment of the causative tick or ticks.

What should I do?

If a tick is found on your pet, but your pet remains bright and well, just remove the tick and observe your animal closely for signs of illness. If your pet is exhibiting signs suspicious of tick paralysis, with or without detection of a tick, the animal should be taken to your vet. Signs frequently worsen even after removal of a paralysis tick, so early, aggressive therapy is important for a successful outcome.

How is it treated?

On diagnosis or suspicion of tick paralysis, your vet will administer tick antiserum to your pet to neutralize the toxin in its circulation and help prevent worsening of signs. A thorough tick search will be performed to try to detect and remove and more ticks. Immature ticks may be too small to detect on initial exam, so checks will be performed regularly during its stay in hospital.

If signs are mild, your animal may just need to be kept in a calm, cool environment and observed for progression of the disease. If signs are more severe, your animal will need to be placed under intensive care. This may involve the use of pharmacological agents, intravenous fluids and artificial ventilation to support the cardiovascular and respiratory systems to keep it alive.

The length of time that your pet will need to be kept in hospital will depend on the severity and progression of clinical signs, and the speed of recovery.

How can Tick Paralysis be prevented?

There are a few key steps in reducing your pet's risk of developing tick paralysis:

• Avoid high-risk geographical areas during the tick season
• Perform daily tick searches - use your fingertips to thoroughly and systematically feel all over your animal (particularly around the head, ears and in skin folds) for small bumps or craters
• It may also be of benefit to clip longhaired cats and dogs in spring to make tick detection easier
• Remove any ticks you find - try not to squeeze the tick, use a fingernail, tweezers or special tick removal hook
• Use tick prevention products - including baths, spays and collars, particularly during the risk periods.
• Speak to your vet about what products are best for your pet

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