With summer around the corner, Centers for Disease Control and Prevention experts are warning --- beware the bugs!
A new report from the agency reveals that diseases transmitted through the bites of blood-feeding ticks, mosquitoes, and fleas are a "growing public health problem" in the United States.
Reported cases of what are called vector-borne diseases have more than tripled nationwide, growing from 27,388 cases reported in 2004 to a whopping 96,075 cases reported in 2016, according to the new Vital Signs report published by the CDC on Tuesday.
Vector-borne diseases are illnesses that are transmitted by vectors, or blood-feeding ticks and insects capable of transmitting pathogens -- bacteria, viruses, or parasites -- from one host to another. Pathogens, transmitted through a vector's bite, cause illness. These include Lyme disease, West Nile virus and Zika virus, to name a few.
"It's very important that the public is very aware that these are more than summertime nuisances -- you can get very severe diseases from ticks and mosquitoes," said Dr. Lyle Petersen, an author of the report and director of the CDC's Division of Vector-Borne Diseases, who actually had West Nile virus himself from a mosquito bite in 2003.
"I was sick at home in bed for more than a week with severe headaches and fever and skin rash and just feeling horrible," he said about his illness. "Then after that, it took me about three months to get back to normal. It was definitely something that ruined my summer."
Vector-borne diseases account for more than 17% of all infectious diseases, causing more than 700,000 deaths annually across the globe, according to the World Health Organization.
The new report, based on data from the National Notifiable Disease Surveillance System each year between 2004 and 2016, identified 16 different diseases: 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.
In all, 642,602 cases of vector-borne diseases were reported during that time period, the researchers found.
Tick-borne illnesses, which accounted for more than 75% of all vector-borne disease reports, grew from 22,527 cases in 2004 to 48,610 cases reported in 2016, the researchers found.
Lyme disease accounted for 82% of the cumulative reported tick-borne diseases, according to the data.
The report identified a steady rise and spread of tick-borne diseases, whereas the occurrence of mosquito-borne diseases was dispersed and more punctuated by epidemics.
The number of mosquito-borne diseases rose from 4,858 in 2004 to 47,461 in 2016, the researchers found. A big jump in those cases occurred in 2016, when 41,680 Zika virus cases were reported.
West Nile virus was the most commonly transmitted mosquito-borne disease in the continental US, with its most notable epidemic occurring in 2012, especially in Texas.
Though rare, plague was the most common flea-borne disease included in the data. Endemic plague, transmitted mostly in the rural southwestern US, did not exceed 17 cases in a year.
The report noted that, since 2004, there have been nine vector-borne pathogens newly identified as concerns among humans in the US: the tick-borne viruses Heartland and Bourbon; Lyme disease-causing Borrelia miyamotoi and Borrelia mayonii bacteria; two new tick-borne spotted fever species, Rickettsia parkeri and Rickettsia 364D; a newly recognized tick-borne Ehrlichia species; and the mosquito-borne viruses chikungunya and Zika.
"Zika, West Nile, Lyme, and chikungunya -- a growing list of diseases caused by the bite of an infected mosquito, tick, or flea -- have confronted the US in recent years, making a lot of people sick. And we don't know what will threaten Americans next," CDC Director Dr. Robert Redfield said in a statement.