May 1 (UPI) -- The number of Americans who got sick from infected mosquito, tick or flea bites tripled over 13 years, mainly from outbreaks of Zika and other diseases, the Centers for Disease Control and Prevention reported Tuesday.
From 2004-16, more than 640,000 cases of illnesses from bites by the insects were reported by the CDC in the newest edition of its Vital Signs update, including 96,075 in 2016. In 2004, there were 27,388 cases.
CDC scientists analyzed data for 16 vector-borne diseases reported to the National Notifiable Diseases Surveillance System.
In 2016, the most common tickborne diseases, accounting for 60 percent of all cases involving bites, were Lyme disease and ehrlichiosis/anaplasmosis. The most common mosquito-borne viruses were West Nile, dengue and Zika. Plague was the most common disease resulting from the bite of an infected flea, although the infections were rare.
"The data show that we're seeing a steady increase and spread of tickborne diseases, and an accelerating trend of mosquito-borne diseases introduced from other parts of the world," Dr. Lyle Petersen, director of the Division of Vector-Borne Diseases in the CDC's National Center for Emerging and Zoonotic Infectious Diseases, said in press release.
The CDC said the numbers have risen at least partially because more mosquito-borne diseases have been introduced from other parts of the world, with a rise in Americans' overseas travel and commerce as at least one cause.
In addition, nine new germs spread by mosquitoes and ticks were discovered or introduced in the Untied States.
Outbreaks of mosquito-borne illnesses increase during the warmer summer temperatures, the CDC said.
"Our nation's first lines of defense are state and local health departments and vector control organizations, and we must continue to enhance our investment in their ability to fight against these diseases," Dr. Robert R. Redfield, the CDC director, said.
The CDC said about 80 percent of vector-control organizations across the United States "lack critical prevention and control capacities" in one or more of five core competencies, such as testing for pesticide resistance.
Broken down by state, California had the most mosquito cases with 9,254 followed by New York with 7,167 and Texas with 6,648. Puerto Rico, as a territory, had 80,534 reports. The fewest cases were Alaska with 87.
For ticks, Pennsylvania led with 73,610, followed by New York with 69,313, New Jersey with 51,578, Massachusetts with 50,234 and Connecticut with 36,727. The lowest was Hawaii with none.
The CDC advises people to protect themselves by using insect repellent, wearing long-sleeves shirts and long pants, and controlling ticks and fleas on pets.