It’s tick season again, North America. As the weather warms and people get out, the chances of an encounter with one of these blood-sucking arthropods increase. In fact, tick problems today appear to be worse than they were 50 or 60 years ago, experts told Live Science.
It pays to be careful; ticks cause at least 50,000 cases of illness in the US each year, and those are just the illnesses that are diagnosed and reported to the Centers for Disease Control and Prevention (CDC).
In fact, the actual rates of tick-borne disease occurrence are likely to be much, much higher. For example, an estimate of 2021 suggests that 476,000 Americans receive treatment for Lyme disease alone each year. (This may overestimate the true number of Lyme infections, according to the CDC, because people are sometimes treated for Lyme as a precaution after being bitten by a tick.)
Although there is no single national surveillance system that detects all cases of tick-borne disease, the risk clearly varies from state to state. In the northeast, where deer ticks (Ixodes scapularis) thrive, Lyme is a concern. In the southeast, where the dog makes ticks (variable skincare) tend to reside, spotted fevers dominate, including the somewhat misleadingly named Rocky Mountain spotted fever.
Tick Encounters on the Rise
Ticks are effective transmitters of disease because they can feed on multiple animal hosts and because they remain attached to their hosts for several days, giving them enough time for pathogens to spread, said Jerome Goddard, extension professor of medical entomology at the Mississippi State University.
Growing deer populations are one of the main reasons tick encounters are on the rise, Goddard told LiveScience. Ticks find food by ambushing passing animals, she said, and if the ticks don’t find a host, they die. When there are more deer, more ticks survive, which means that deer and tick populations are closely linked. The development of rural areas, bringing people into closer contact with ticks, also plays a role, According to the Centers for Disease Control and Prevention. Finally, climate change it can alter the ranges of ticks and tick pathogens in ways that are not yet fully understood, which may also increase the likelihood that people will interact with ticks.
According to the CDC Tick Bite Data Tracker, May and June are the peak months for tick bites that send people to the emergency room. During these months, the Northeast sees the most tick-related emergency room visits per 100,000 people, followed by the Midwest and then the Southeast.
Lyme disease, which is caused by the bacteria Borrelia burgdorferi and transmitted by deer ticks, most commonly affects people in the Northeast and Midwest, as does anaplasmosis, another bacterial disease transmitted by deer ticks. People in the Mid-Atlantic and Southeast are at increased risk for spotted fevers, including Rocky Mountain spotted fever, which is caused by the bacteria Rickettsia rickettsia.
Ehrlichiosis, a bacterial infection transmitted by both deer ticks and the lone star tick (Amblyomma americanum), is most commonly reported in the mid-Atlantic, the south, and in Arkansas, Missouri, Oklahoma, and Kansas.
Typically, these tick-borne bacterial infections present with symptoms such as fever, headache, rash, and chills. All are treatable with antibiotics when caught early, but missed infections can be fatal. Infections can also cause long-term problems. For example, a subset of people who get ehrlichiosis later develop an allergy to red meat, Live Science previously reported.
These bacterial diseases have long been a consequence of tick bites. More recently, however, doctors and scientists have identified a number of viral diseases that ticks also transmit. These include the Heartland and Bourbon viruses, which have been reported primarily in the South and Midwest. These viruses can cause fever, fatigue, headache, diarrhea, joint pain, and sometimes low platelet and white blood cell counts. There are no treatments for these viruses. Most people recover, but some patients have died. More serious is the Powassan virus, spread most often by ticks in the Northeast and Great Lakes regions, which is capable of infecting the brain and the membranes around the spinal cord.
Fight against tick-borne diseases
With tick-borne diseases a growing problem, researchers are looking for ways to fight back. At SUNY Upstate Medical University in Syracuse, New York, microbiologist and immunologist Saravanan Thangamani and his team are working to develop vaccines for emerging tick-borne viruses, especially Powassan virus. These viruses are transmitted immediately when a tick bites, Thangamani told Live Science, so vaccines are needed that prevent the viruses from replicating in the human body and spreading beyond the skin.
Bacterial diseases are another story. In most cases, it takes 24 to 36 hours for the bacteria that cause these illnesses to spread after the initial bite. Instead of trying to develop vaccines for each individual disease, Thangamani and other scientists are looking for vaccines that target ticks.
An effective tick vaccine would work by targeting a cocktail of proteins found in tick saliva. Ticks inject a dynamic mix of these proteins during feeding days to anesthetize the skin and evade host attack. immune system. Animal trials led by researchers at Yale University have shown that a the tick vaccine can interfere with tick feeding and cause them to leave their host quickly, Live Science previously reported.
“I feel like in the next three to five years we should have some good candidates” for vaccines, Thangamani said.
Meanwhile, the best defense is a good offense. To avoid tick bites in the first place, dress appropriately when in tick-heavy areas, Goddard advised. Tucking pants into rubber boots, or at least socks, can keep ticks at bay.
“If you’re wearing boots, leather boots, ankle-high boots and pant legs flapping in the breeze, that’s a pant-leg interstate,” Goddard said.
Treating your clothing with a spray containing the insecticide permethrin will kill ticks on contact. (Insect repellents containing DEET also help, Goddard said, but not as effectively.) Lastly, checking his body for ticks after outdoor activities is key, Goddard said. If you find an attached tick, immediately remove it with tweezers by grasping it close to the skin and pulling upwards.
Mark tick bites on a calendar so that if you get sick in the next few weeks, you can tell your doctor that you were bitten and the date of the bite, Goddard said. There are some paid services that will test ticks for disease, as well as a limited number of state health departments and research organizations that will do the same for free. One of those organizations, NYticks.org, is in charge of Thangamani’s lab. The researchers have analyzed nearly 20,000 ticks, mostly from New York state, and have a real-time data dashboard for the state that shows which pathogens are present in which counties.
“The real-time presentation of data is what’s unique and very, very powerful,” Thangamani said.
Originally published on Live Science