Here are key takeaways from the season premiere of Kentucky Health, which examines arthropod-borne diseases. The guest is Subba Reddy Palli, PhD., Kentucky’s state entomologist and chair of the Department of Entomology at the University of Kentucky Martin-Gatton College of Agriculture, Food, and Environment.
1) Research shows a drop in the number of arthropod species around the world.
Palli says several studies indicate a decrease in both the “number and abundance” of arthropod species in recent years. The phylum arthropoda includes classes of invertebrate animals such as insects (including bees and flies), arachnids (spiders), chilopods (centipedes), and many others.
Human activity is contributing to the change, Palli explains. This can occur through ongoing climate change caused by burning fossil fuels, or through habitat manipulation that transforms formerly wooded areas into residential neighborhoods, business parks, or farms. Pesticide use is another cause, he adds.
“With climate change, as temperatures change, the physiology, development, behavior, and life history of insects change,” Palli says. “The insects that can adapt to these changing conditions do better. The ones that are not able to cope with these conditions do not do so well, and even disappear.”
2) Ticks present the gravest threat as disease vectors in the U.S.
Palli says mosquitos have traditionally been considered more harmful to humans due to the history of mosquito-borne diseases such as malaria, West Nile virus, and yellow fever. But the danger caused by mosquitos is largely confined to southern states, he explains, while ticks are present in most of the U.S.
Diseases transmitted by ticks include Rocky Mountain spotted fever, ehrlichiosis fever, and a red meat allergy known as alpha-gal syndrome. These are transmitted by the Lone Star tick, which is common in Kentucky. The deer tick, which is more common in the eastern states, can transmit Lyme disease, a chronic bacterial illness.
Much like mosquitos, ticks can infect humans when they attach to the skin and take a blood meal for nourishment. But unlike their airborne relatives, ticks can latch onto a human host for a much longer period of time.
“Ticks have to be on you for hours, if not days, before they take a full blood meal and transmit these pathogens,” he says. “So one good grace with ticks is you have some time.”
Palli recommends people check their body thoroughly for ticks as soon as they return from any sort of outdoor activity that lasts longer than a few minutes, especially if it takes place in wooded areas with piles of leaves, such as a hike. Ticks should be extracted from the skin slowly and carefully with tweezers, grabbing it by the head in order to remove its mouth.
“When you find a tick on you, don’t get freaked out,” Palli says. “The chances of it injecting a pathogen into you is not that high.” If bitten, he recommends getting a dose of antibiotics as soon as possible to combat any bacterial or viral diseases the tick may have transmitted.
3) A warming planet could increase threats of insect-borne diseases.
Palli says most research indicates that higher global temperatures will lead to a reduction in arthropod species. But he adds that a hotter climate can also cause an increase in disease-vector insects such as mosquitos.
“At the same time we are losing biodiversity of insects, there is also an increase in some insects – especially in temperate areas – that are disease vectors,” he explains.
Researchers are devising ways to manage the populations of these insects, Palli says, but learning and practicing personal habits to reduce exposure is still the best way to prevent diseases.
“You can use repellents, products that contain DEET (an active chemical ingredient), cover yourself, and walk on paved trails – and when you come back, remove any ticks and check yourself carefully,” Palli advises.
Related material: Insects: Most Are Good, but Watch the Bad