Though ticks hold the potential to spread a range of harmful diseases to the human population, tick saliva could hold the key to treating several life-threatening ailments. Scientific research at the beginning of the 21st century is beginning to present clues that a certain protein in the spit of ticks, called rEV576, might reduce the progress of a severe degenerative disease called myasthenia gravis. Other studies have found anti-cancerous qualities in the protein of a South American tick's saliva and maybe even a potential vaccine for the lyme disease that ticks are known to pass to humans or other animals.
A 2009 article in the Annals of Neurology journal details a study by researchers at Saint Louis University that showed tick saliva to be a so-called complement inhibitor. These substances are known to improve response in the body's neuromuscular nerve receptors, which are impeded in patients with myasthenia gravis — a disorder that causes muscular weakness, poor eyesight and labored breathing. Scientists hope to develop a drug, called EN101antisense, that works to reverse the effects of this disorder, which affects about 500 out of every 1,000,000 people.
The tick saliva from a certain South American species, Amblyomma cajennense, also has been proven to leave vital tissue alone while killing cancerous cells. According to a 2009 study by researchers at Brazil's Instituto Butantan, a protein isolated from the saliva, known as Factor X active, was responsible for completely eradicating tumors in lab rats within 42 days. As with the myasthenia gravis research, however, it could take years more to develop a medication suitable for human trials.
Ticks are not known to be progenitors of good human health. In addition to lyme disease from deer ticks, many other diseases have been known to be spread by tick saliva, including Rocky Mountain spotted fever, tularemia, ehrlichiosis, babesiosis and a form of encephalitis. More than just humans are susceptible, as bovine babeiosis, or Texas fever, can nearly eradicate a herd in weeks.
Though many diseases spread through tick saliva take only about an hour to be transmitted through a bite, others like lyme disease take as long as a full day to pass from the insect to the new host. This factor gives some scientists hope that they can isolate the approximate 400 proteins in tick saliva and find a way to create a vaccine to keep people from contracting lyme disease in the first place. Research into this facet of immunology began in 1994.