Fifty years ago, ticks were merely a nuisance. People discussed the best way to remove them. Something has changed. Today, ticks transmit several diseases, among them Lyme disease named for Old Lyme, Connecticut, where the disease was identified in 1975. The tick population is increasing and spreading to new locations. Lyme disease is caused by a bacterium that survives in warm blooded animals including birds, mice, deer, dogs, cats, and people. Ticks are the vector; they transmit Lyme and other diseases from one host to another.
The reason that tick populations are spreading is unknown, but one possibility is that human development of the land has disrupted animal predator/prey relationships where the predator species is greatly diminished and the population of the prey species increases. If ticks have easy access to the abundant prey animals, then the tick population can increase. Another possibility is changing weather patterns. Ticks can survive cold weather, but they prefer a warm and humid environment. We seem to be getting longer summer seasons and more rain in some places.
Treatment for diseases caused by ticks has some complications. The most effective treatment for bacterial disease transmitted by a tick is immediate treatment, usually an antibiotic. However, not every tick carries disease. Tests to determine whether Lyme disease is present are not very effective until the disease is in a somewhat advanced stage. Ticks can carry and transmit more than one disease or more than one variation of a bacterial disease. One test doesn’t identify all of them. Ticks also transmit Rocky Mountain Spotted Fever which requires its own diagnostic procedures. A different type of tick can transmit a viral disease requiring yet another treatment regimen.
The U.S. Centers for Disease Control has identified 16 diseases that are transmitted by ticks. Some of those diseases have serious consequences if not promptly diagnosed and treated
Avoiding tick encounters is the best solution. If you are outside working or playing where you may come into contact with grass or bushes, a repellant is recommended. But not just any repellant. From a biologist’s perspective, ticks are not insects; they are arachnids. The U.S. Centers for Disease Control recommends using a repellant that contains permethrin. The U.S. Environmental Protection Agency lists several repellant products. The repellant should be applied to shoes and outer clothing — not to skin.
A May 1, 2018, Centers for Disease Control press release reported that, between 2004 and 2016, the number of diseases transmitted by ticks, fleas, and mosquitos tripled. Mosquitos can transmit 17 diseases. Ticks, fleas, and mosquitos are in the environment all around us. We and our pet animals are easily exposed to these disease vectors. Because of the advancing distribution of the vectors and the diseases they transmit, caution is advisable.
Those summer picnics will be a lot more fun without the uninvited guests.