The warmer weather of spring and summer means the start of tick and mosquito season and the diseases they transmit, including Lyme disease, Rocky Mountain spotted fever, West Nile and Zika.
A new report from the Centers for Disease Control and Prevention has found that illnesses from mosquito, tick and flea bites more than tripled in the United States from 2004 to 2016.
The report, released Tuesday, shows that the number of reported cases of these diseases jumped from 27,388 in 2004 to more than 96,000 in 2016. The data include illnesses reported in the U.S. states and territories. During that period, a total of more than 640,000 cases of these diseases were reported to the CDC.
Officials say the actual number of people who have become sick is much higher, in part because many infections are not reported or recognized. Some patients may experience mild symptoms and not seek medical attention, and not all diseases were reported for the full 13-year analysis period or from all states and territories. The data “substantially underestimate disease occurrence,” the report said.
For example, recent data from clinical and laboratory diagnoses estimate that Lyme disease infects about 300,000 Americans every year, which is eight to 10 times more than the number reported in the CDC analysis. In 2016, the number of Lyme diseases reported for the United States was 36,429.
As a group, these diseases in the U.S. are notable for their wide geographical distribution and resistance to control. Only one of the diseases, yellow fever, has a vaccine approved by the Food and Drug Administration.
The responsibility for detecting and responding to diseases spread by vectors such as mosquitoes and ticks is almost all funded locally and operated by local and state health departments. But their resources have been greatly reduced over the years.
The increase in disease cases caused by the bite of an infected mosquito, tick or flea in the United States is most likely the result of many factors. Mosquitoes and ticks and the germs they spread are increasing in number and moving into new areas. As a result, more people are at risk for infection. Overseas travel and commerce are also increasingly common, and someone infected with a mosquito-borne disease like Zika in one country can unknowingly transport it home.
