The number of people being infected by diseases from mosquitoes, ticks and fleas has tripled in the United States from 2004 to 2016, according to a new report by the Center for Disease Control. There were more than 640,000 cases of these diseases reported during the 13 years analyzed.
In addition to increases in number of infections, there were also nine new germs spread by mosquitoes and ticks that were discovered.
The report listed increased world travel among one of the major factors in the increase in disease. Infected travelers have the potential to introduce and spread germs from country to country.
While travel has aided the spread of these illnesses, the main explanation for the increase is changes in climate that lead to more mosquitoes, and eventually more cases of these diseases, according to the CDC.
Higher temperatures and longer warm seasons increase risk for these illnesses in a variety of ways. First, mosquitoes develop faster in warmer weather.
Milder winters and earlier springs result in longer mosquito seasons, larger mosquito populations and a longer time for people to be at risk.
In the U.S., it is very likely that climate change has contributed to the northern expansion of ticks that carry Lyme disease and has also led to a longer season of risk to acquire a tick-borne infection, according to Ben Beard, the deputy director of the CDC's Division of Vector-Borne Diseases.
Since 2003, the U.S. has seen a warming trend during the summer season, according to AccuWeather Senior Meteorologist and Lead Long-Range Meteorologist Paul Pastelok. Throughout the country, there has been an increase in temperature over the last 15 years.
In addition to temperature, one major factor for the number of mosquitoes is how wet an area is. Mosquitoes use water to breed, so an area with increased rainfall in the spring and early summer will typically see more mosquitoes throughout the summer.
The 2018 summer forecast predicts areas that will be hot and wet, and therefore can deliver a good idea of which areas of the country will see an increase in ticks and mosquitoes.
"The Tennessee Valley is one area that's been hit with a lot of rainfall [during previous] springs and early summers," Pastelok said. "And this year, it's no different."
Rainfall departures are doubled in the Tennessee Valley for the spring so far, according to Pastelok.
AccuWeather's 2018 summer forecast for precipitation departures from normal.
According to the report, the U.S. is not prepared to face this public health threat. Health departments have seen an increased demand in aid for the diseases, especially during the Zika virus epidemic in 2015 and 2016.
"Recent outbreaks of Zika, chikungunya, and West Nile virus and the steady increase of Lyme disease cases highlight the need for states to have comprehensive vector prevention and control programs," Lyle Petersen, the director of the CDC's Division of Vector-Borne Diseases, said.