How you can combat tick- and mosquito-borne disease

Christina Nelson, MD, MPH

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.

• Rash: Lyme disease, southern tick-associated rash illness (STARI), Rocky Mountain spotted fever (RMSF), and ehrlichiosis result in distinctive rashes.

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.

Prevention

Nelson shares the following tips to pass on to patients and families about tick prevention.

• Wear repellents registered by the US Environmental Protection Agency (EPA). Parents should apply repellent to children, avoiding the hands, eyes, and mouth. People who spend a lot of time outdoors should consider treating clothing and gear with products containing 0.5% permethrin.

• Emphasize the importance of tick checks. People should check themselves and their children for ticks after spending time outdoors. Places that ticks frequently hide are in the ears, on the back of the neck, hairline, and in the groin area.

• In conjunction with the tick check, it’s helpful to remove clothing where ticks might be hiding, and take a shower to wash off any unseen ticks. Research has shown that showering within 2 hours of coming indoors can protect against Lyme disease.

• Finally, tell patients who spend time in tick habitats or find an attached tick to watch for fever and rash, and to see their physician if they have any symptoms or concerns.

Monitoring and disease control

Increasing disease and prevalence is exacerbated by the fact that our global society makes it easier than ever to spread, according to the CDC. Infected travelers and worldwide commerce bring vectors from other parts of the world to the United States, says the agency.

Some of the top mosquito-borne diseases include: California serogroup viruses, Chikungunya virus, Dengue viruses, Eastern equine encephalitis virus, malariaPlasmodium, Saint Louis encephalitis virus, West Nile virus, yellow fever virus, and Zika virus. Tick-borne diseases include anaplasmosis/ehrlichiosis, babesiosis, Lyme disease, Powassan virus, spotted fever group rickettsioses, and tularemia.

“Recent outbreaks of Zika, chikungunya, and West Nile viruses and the steady increase in Lyme disease cases point to the need for state and local agencies to have comprehensive vector-borne disease prevention and control programs,” the CDC says. “The United States needs better tools and more staff with greater expertise at local and state levels to reduce the growing threat of these diseases.”

Vectors are more prevalent in some areas of the country, with the top 20% of mosquito-borne diseases found in Arizona, California, Colorado, Florida, Illinois, Maryland, New Jersey, New York, and Texas. The top 20% of tick-borne disease cases are found in Connecticut, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Virginia, and Wisconsin.

Local and state health departments, as well as local vector control organizations, aren’t prepared to handle the increased burden, says the CDC, with 80% of vector control organizations needing improvement in 1 or more of 5 competencies, such as testing for pesticide resistance. Other core competencies include local mosquito and tick monitoring; using data to drive local decisions about vector control; having an action plan to control vectors at every life stage; and using a variety of methods for vector control.

The federal government is working to increase funding for vector surveillance programs; is convening a Tick-Borne Disease Working Group to improve coordination of tick-borne disease efforts; and has created 5 regional centers to address emerging diseases from mosquitoes and ticks. It’s also important that state and local agencies build and sustain public health programs to test and track vectors, and educate the public about prevention and control methods, says the CDC.