Tick Off
BY JENNIFER DAVIES
There are very few things as revolting as finding a big fat tick on your pet. They are, at best, annoying and repulsive and, at worst, can transmit serious diseases. Although they occur all year around, summer in sunny South Africa is prime time for these eight-legged pests that drink blood. Fortunately, there is much we can do to protect ourselves and stay safe while still enjoying the great outdoors.
Know Your Enemy Ticks are arachnids (the same family as spiders), which live on the blood of mammals, birds, amphibians and reptiles. There are around 900 types of tick on earth, most of which pose no threat to us. You’ll find them in low-growing bush - and scrubland, tall grass, ferns, fallen leaves, shady woodlands, and meadows – pretty much anywhere in SA. They require humidity in order to metamorphose from egg to larva and to stay hydrated, so warm, moist climates are ideal – summer rainfall areas are their favourites as well as springtime after winter rainfall. They’re a pretty diverse group, ranging in size from 3mm to 6mm in length, although nymphs (the stage between larva and adult) can be so small that they’re near impossible to see (‘pepper ticks’). They can have hard or
soft bodies, be plain or patterned, and vary in colour from yellow, grey, and beige, to brown and black; they tend to look blue-grey-green when full of blood. Ticks have a complex life cycle involving several hosts and habitats, which takes place over a few months. As a result, it is impossible to control them in the environment, and their exposure to multiple hosts and potential pathogens means that they could be carrying any number of diseases. The most commonly problematic ticks in SA are the kennel or brown tick (Rhipicephalus sanguineus), which can transmit the parasite Babesia spp. and the bacteria Ehrlichia spp., the yellow dog tick (Haemaphysalis elliptica), which can transmit babesia, and the bont tick (Amblyomma hebraeum), which can transmit Rickettsia africae (African tick bite fever) bacteria to humans.
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Tick-bite timeline To understand why ticks can make us sick, we need to know how they feed:
1. The tick cuts a hole in the host’s
skin with its mouth parts. Most of the time, the host does not notice this bite.
2. A hard, barbed structure near its mouth, called a hypostome, is inserted into the host.
3. It injects its saliva which contains an anaesthetic so that the host won’t realise it’s there, and an anticoagulant to keep the blood flowing. Some ticks also secrete a cement-like substance to help them stay attached. If the tick is carrying a transmissible pathogen, it too can be injected along with the saliva. Transmission is usually not instantaneous – it takes anything
JANUARY 2022 | PETPRINTS
