New Zealand is home to ticks, arachnids related to spiders. While often associated with livestock, ticks can also attach to humans. Understanding the types of ticks present and how to manage encounters is important for anyone in New Zealand.
Identifying New Zealand’s Ticks
The most common tick encountered in New Zealand is the New Zealand cattle tick (Haemaphysalis longicornis). This introduced species is widespread, particularly across the North Island and parts of the South Island, thriving in moist, warm-temperate environments. Unfed adult Haemaphysalis longicornis ticks are typically around 3mm long and reddish-brown, swelling to about 9mm and turning blue-black after feeding.
New Zealand also has several native tick species, but these generally infest specific hosts like birds or tuatara and do not bite humans. While the Australian paralysis tick (Ixodes holocyclus) is frequently intercepted at the New Zealand border, it is not established in the country. Ticks commonly inhabit areas with long grass, dense shrubs, and leaf litter, and are most active during warmer months, though they can be found year-round.
Health Implications of Tick Bites
While many tick-borne diseases, such as Lyme disease, are not endemic in New Zealand, tick bites can still pose health concerns. The most common reaction is localized irritation, including redness, itching, and swelling at the bite site. More severe allergic reactions are possible, ranging from significant swelling to, rarely, anaphylaxis, especially if the tick is disturbed during removal.
A less common health implication is mammalian meat allergy, also known as alpha-gal syndrome. This allergy can develop after a tick bite, where the tick transfers a sugar molecule called alpha-gal from a previous mammal host. Subsequent consumption of red meat (beef, pork, or lamb) can trigger a delayed allergic reaction, usually occurring three to eight hours later. Symptoms may include hives, swelling, abdominal upset, and rarely, life-threatening anaphylaxis.
Preventing Tick Encounters
Proactive steps can reduce tick bites. When outdoors, especially in areas with long grass, dense vegetation, or bush, wear long-sleeved shirts and long trousers. Tucking trousers into socks or boots creates a barrier against ticks. Applying insect repellents with DEET or picaridin to exposed skin deters ticks.
After outdoor activities, thoroughly check yourself, children, and pets for ticks. Ticks often attach in areas like the navel, groin, scalp, behind the ears, and armpits on humans. For pets, common attachment sites include under collars, inside ears, and between toes. Keeping grass and vegetation trimmed around your home can help reduce tick populations.
Responding to a Tick Bite
If a tick is attached to the skin, prompt and careful removal is important. Use fine-tipped tweezers or a specialized tick removal tool to grasp the tick close to the skin’s surface. Pull steadily upwards with even pressure, avoiding twisting or squeezing the tick’s body; this can cause it to inject more saliva or break off its mouthparts. Do not use heat, petroleum jelly, or other substances to make the tick detach.
After removing the tick, clean the bite area with soap and water or an antiseptic. Monitor the bite site for signs of infection, such as increased redness, swelling, pain, or oozing. Seek medical attention if you cannot remove the entire tick, if a rash or flu-like symptoms develop, or if you experience signs of an allergic reaction, particularly difficulty breathing or widespread hives.