Ticks are widespread throughout the U.S., and while bites can be harmless they also hold the potential to transmit serious diseases. Lyme disease — which is caused by Borrelia burgdorferi bacteria spread through the bite of blacklegged ticks (also known as deer ticks) and western blacklegged ticks — is thought to affect more than 300,000 Americans annually.1 As you can view for yourself in the video above, ticks are stealthy creatures that have developed an elaborate system to feed off human blood.
Whereas other bloodsuckers like mosquitoes bite, suck quickly and leave, ticks’ goal is to stay embedded in your skin for days, and as such they have specially developed mouths just for this purpose. In addition to the needle-like hypostome, which is covered in backward-facing hooks, there are two rod-like chelicerae, which help to drive the hypostome into your skin.2 You can’t feel it when a tick bites you, nor when they feed.
Their salvia contains anesthetics for this purpose, along with anticoagulants and immune suppressors that facilitate the ticks’ feeding while also allowing the transmission of diseases like Lyme.
“On a human host, their saliva numbs the skin so you don’t feel the bite, and an anticoagulant keeps the blood flowing. The tick saliva also combines with a protein from B. burgdorferi to suppress human immune systems, so our bodies don’t muster antibodies to kill the bug,” the Adirondack Daily Enterprise reported.3
“Reading about the elaborate and effective ways these tiny creatures defeat our body’s defenses can make you rethink the conception that humans occupy the top spot on an evolutionary ladder. They have been around far longer than we have, and from all indications, they will persist when we have faded away.”4
How Do Ticks Spread Disease?
In order to transition to each of its life stages (egg, larva, nymph and adult), ticks must find a blood meal to survive. Ticks can live up to three years during this process, although many die prior to this when they are unable to find a host to feed on. Ticks will lie in wait on a leaf or piece of grass, waiting to detect a potential host via breath and body odors or sensing heat, moisture, vibrations and even shadows.
If you happen to venture too close to a tick’s hideout, it will climb on board and begin the process of attaching, which can take anywhere from minutes to two hours.
As a tick sucks blood over the process of several days, it ingests any pathogens found in the host animal. In the case of Lyme disease bacteria, white-footed mice infect 75 to 95 percent of larval ticks that feed on them.5 Such pathogens within the tick may then be transmitted to the host via saliva released during the feeding process.6
There are more than two dozen tick-borne diseases in the U.S. that can be transmitted to humans, including Colorado tick fever, rocky mountain spotted fever, Powassan disease and increasingly prevalent Lyme disease.
In most cases, tick bites cause no symptoms, but it’s possible to experience pain, a rash or burning. If you develop a red spot or rash near the site of a tick bite, it’s a possible sign of tick-borne disease and should be evaluated by your doctor. A characteristic “bull’s-eye” rash is often associated with Lyme disease, but this rash occurs only in about half of those infected, so absence of such a rash does not exclude the possibility of a tick bite.
Lyme Disease Is on the Rise
While only deer ticks are known to transmit Lyme disease, cases have now occurred in half of the counties in the 48 continental U.S. states.7 Lyme disease is the most commonly reported vectorborne illness in the U.S., according to the U.S. Centers for Disease Control and Prevention (CDC), with 95 percent of confirmed cases in 2015 coming from the following 14 states:8
According to the International Lyme and Associated Diseases Society (ILADS), since U.S. surveillance began in 1982, the number of annual Lyme cases reported has increased nearly 25-fold.9 The disease is also spreading geographically. The longer a tick is attached, the higher the chances of transmission of an infectious agent. In most cases, Lyme disease is transmitted by young nymphs, rather than adult ticks, simply because the nymphs are smaller and therefore less likely to be discovered and removed.
According to the CDC, the tick must typically be attached for 36 to 48 hours or more before the Lyme disease bacterium can be transmitted,10 but ILADS notes that it’s possible to get Lyme disease even if the tick has been attached for less than 24 hours.11
Many patients with Lyme disease do not ever recall being bitten by a tick and, according to Dr. Dietrich Klinghardt — one the leading authorities on Lyme disease — the bacteria that cause the disease can also be spread by other biting or blood-sucking insects, including mosquitoes, spiders, fleas and mites.