Your Weekly Checkup: Diseases from Ticks, Mosquitoes, and Fleas Are on the Rise

“Your Weekly Checkup” is our online column by Dr. Douglas Zipes, an internationally acclaimed cardiologist, professor, author, inventor, and authority on pacing and electrophysiology. Dr. Zipes is also a contributor to The Saturday Evening Post print magazine. Subscribe to receive thoughtful articles, new fiction, health and wellness advice, and gems from our archive. 

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The Centers for Disease Control and Prevention issued a new report stating that illnesses caused by the bite of an infected mosquito, tick or flea (vector-borne diseases) have more than tripled in the United States from 2004 to 2016. Warmer weather has permitted widespread proliferation of ticks, which transmit Lyme disease, Rocky Mountain spotted fever, and tularemia; and mosquitoes, which transmit West Nile virus, Zika, dengue, and chikungunya. Warmer temperatures also tend to make mosquitoes get infected faster and become more infectious, so when they bite, they deposit a larger viral load, increasing the chances of infection. An increase in the deer population infected with deer ticks has helped skyrocket the incidence of Lyme disease, while decreases in predators, such as foxes that keep the rodent population under control, also play a role. More people moving into wooded areas increases human exposure to the vectors.

These diseases have wide geographical distribution and can be difficult to control. Overseas commercial and vacation travel facilitate rapid transmission. Of the diseases found in the U.S., only yellow fever has a vaccine to prevent infection.

Tick-borne diseases make up more than 75 percent of U.S. infection reports (mostly Lyme disease) and tend to concentrate in the eastern parts of the U.S. and along the Pacific Coast. Mosquito-borne illnesses like dengue fever, chikungunya and Zika are found in Puerto Rico, the Caribbean Islands, and some parts of the United States. West Nile virus is widespread across the continental U. S., where it is the major mosquito-borne disease. Plague, the most common flea-borne disease, is found mostly in rural southwestern U.S., and there are less than 17 cases a year.

The new report identified 16 different vector-borne diseases, including Lyme disease, anaplasmosis/ehrlichiosis, spotted fever rickettsiosis, babesiosis, tularemia, Powassan virus, dengue viruses, Zika virus, West Nile virus, malaria, chikungunya virus, California serogroup viruses, St. Louis encephalitis virus, Eastern equine encephalitis virus, yellow fever virus, and plague. New pathogens have been found, such as the tick-borne Heartland and Bourbon viruses from the Midwest.

What Can You Do to Prevent Infection?

When outside

Around your house

If you find a tick

These transmitted diseases are much more than warm weather nuisances. Some of them can kill or produce severe, long lasting illness. Rocky Mountain spotted fever isn’t limited to the Rocky Mountains, and Lyme disease can be a chameleon lingering painfully for months. Forewarned is forearmed.