Tick bite paralysis is more common than you think. Majority of its cases have been seen in Australia and United States; sporadic cases have also occurred in Europe, Africa and South America.
So what exactly is tick bite paralysis?
Tick paralysis can be defined as an acute, ascending motor paralysis which can often end being fatal for the victim (both humans and animals), especially if the tick is not located and removed immediately. Generally, the tick may be attached to the victim’s head or neck, though tick paralysis could occur from bites on any part of the body including the groin, chest, back, limbs etc. The causative agent of such paralysis is the toxin (neurotoxin called Holocyclotoxin) in the tick’s saliva. It is believed that the intensity of the paralysis is often due to the proximity of the tick to the victim’s important organs like the brain. The toxin damages or destroys the cells of the central nervous system.
Clinical features of tick bite paralysis are:
- Restlessness in the bitten human/animal.
- Weakness in lower limbs which starts spreading. The victim might fall down and/or show in-coordination.
- Cranial nerve weakness.
- In children, apart from restlessness and irritability, there may be vomiting, anorexia, malaise. The symptoms can often turn fatal.
- In dogs, paralysis ticks may be present around the anus under the tail, in the ears, or in between the toes. Dog owners, who find even a single paralysis tick on their pet, should search further to ensure no other ticks are present.
- Dogs typically exhibit signs like wobbliness in hind limbs, excess salivation, general lethargy and weakness, changes in bark, vomiting, loss of appetite etc. If these signs are present, immediate veterinary assistance must be sought.
- Ticks often fall off before being found, but they might leave behind a red, raised bump or bite mark on their victim.
- Unlike snake or spider bites; tick bite paralysis symptoms do not occur immediately; rather they take 4-5 hours or even a couple of days to show up, after the bite has occurred.
In mild cases, the symptoms usually disappear after the tick has been located and removed completely.
Species of ticks causing tick paralysis
In Australia, the species causing tick bite paralysis is the grass or seed tick (Australian tick called Ixodes holocyclus) which is generally found in humid conditions in forests or at the edge of rainforests etc. This tick usually feeds on birds, mammals and occasionally humans.
Before getting a blood meal, the tick is barely visible and measures only up to 0.5 mm in length. As it feeds, it engorges and grows in size. Typically, a tick might feed for 4-6 days after finding a suitable host. Do note that the Ixodes holocyclus can survive for nearly 70 days without a blood meal. Once the female tick attaches to the host, it only injects its toxin in its victim after the 3rd day of attachment. The male Ixodes holocyclus does not feed immediately on its host; rather it searches their body for a female tick for mating.
Appearance of paralysis causing ticks:
- Typically, the middle 2 legs are lighter in color than the other pairs
- The legs are bunched up in the upper part of the body near the head region
- Australian paralysis ticks have long snouts in the mouth area.
What to do if you find paralysis tick on your pet or person
- Never pull off the tick with bare hands; use tick grabbing devices, forceps or tweezers. If contact with skin occurs, wash immediately with antibacterial solution.
- Remove the tick completely to ensure that it does not leave its mouthparts in the skin
- There are many myths surrounding the removal of ticks including the use of matches, kerosene etc. These are ineffective and also dangerous.
- Once removed, place the tick in spirit or alcohol to kill it. Alternatively, dispose the tick off by flushing it down the drain. You might also keep it for having it identified by an expert.
Sometimes, residual effects of the tick bite paralysis may be seen after 3-4 days of tick removal. So, do keep an eye out on the bitten individual/animal. Watch out for signs of fever, muscle weakness, etc and seek immediate medical attention if these signs are noted.
Treatment for tick bite induced paralysis
The treatment varies from person to person based on the severity of symptoms. In case of dogs, the vet might stabilize the animal and would typically prescribe antiserum, sedation, supportive fluids or oxygen. Hospitalization for couple of days may be required.
In humans, younger children are more susceptible to tick bite paralysis as it may be days before they alert the presence of ticks on them. People living in tick prone areas must inspect their children from time to time taking care to check areas hidden under the hair. Immediate medical help must be sought if aforementioned signs of tick bite paralysis are present.