The number of Americans who have fallen ill to diseases spread by ticks, mosquitos, and fleas tripled from 2004 to 2016, according to the Centers for Disease Control and Prevention (CDC), highlighting the need for vigilance when it comes to protection.
Pediatricians can help by assessing bug repellent use in children, and keeping up on disease surveillance, the agency says.
The prevalence of diseases spread by ticks alone has doubled, the CDC notes, but it is mosquito-borne diseases that most often result in epidemics. Chikungunya and Zika viruses are 2 of the mosquito-borne diseases for which outbreaks were recently reported as occurring for the first time in the United States.
Christina Nelson, MD, MPH, a practicing physician and medical officer with the CDC’s Division of Vector-borne Diseases, says the threat of mosquito and tick-borne diseases is growing and pediatricians play a major role in keeping their patients safe.
“From 2004 to 2013, 9 new pathogens—7 tick-borne and 2 mosquito-borne—have been discovered to infect people or introduced into the United States,” she says. “Cases of vector-borne diseases are underrecognized and underreported in the United States.”
Nelson says she hopes this guidance from the CDC will help clinicians address this threat and educate patients about prevention and control. Clinicians should be watching and testing for mosquito- and tick-borne diseases in patients with compatible signs and symptoms, and be aware of any recent travel or history of tick bites.
Signs and symptoms
Diagnosing and treating these diseases can be difficult because their presentation may at first seem generic. “Many tick-borne diseases can have similar signs and symptoms,” Nelson says.
According to Nelson, the most common symptoms of tick-related illnesses are:
• Fever/chills: With all tick-borne diseases, patients can experience fever at varying degrees and time of onset.
• Aches and pains: Tick-borne disease symptoms include headache, fatigue, and muscle aches. With Lyme disease one may also experience joint pain. The severity and time of onset of these symptoms can depend on the disease.
In Lyme disease, the rash may appear within 3 to 30 days, typically before the onset of fever. The Lyme disease rash is the first sign of infection and is usually a circular lesion called erythema migrans (EM). This rash occurs in approximately 70% to 80% of infected persons and begins at the site of a tick bite. It may be warm, but is not usually very painful or itchy. Some patients develop additional EM lesions in other areas of the body several days later.
The STARI rash is nearly identical to that of Lyme disease, with a red, expanding "bull’s-eye" lesion that develops around the site of a Lone Star tick bite. Unlike Lyme disease, STARI has not been linked to any arthritic or neurologic symptoms.
The rash seen with RMSF varies greatly from person to person in appearance, location, and time of onset. About 10% of people with RMSF never develop a rash. Most often, the rash begins 2 to 5 days after the onset of fever as small, flat, pink, nonitchy macules on the wrists, forearms, and ankles and spreads to the trunk. It sometimes involves the palms and soles. The red to purple, spotted petechial rash of RMSF is usually not seen until the sixth day or later after onset of symptoms and occurs in 35% to 60% of patients with the infection.
In about 30% of patients—and up to 60% of children—ehrlichiosis can cause a rash. The appearance of the rash ranges from macular to maculopapular to petechial, and may appear after the onset of fever.
Nelson says that while most bacterial tick-borne diseases are treatable with antibiotics, they can sometimes be difficult to diagnose. Early recognition and treatment of the infection decreases the risk of serious complications, she adds.
Nelson adds that ticks are most active from April through September, but can be active any time the ground temperature is above 50°F.