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c o n s u m e r h e a lt h Taking the Bite Out of Insect- and Tickborne Diseases transmit are often specific to the disease; not all mosquitoes can transmit West Nile virus, and different mosquitoes transmit chikungunya virus. “Further,” he adds, “persons living in these areas may have more outdoor exposure to these bugs, and their dwellings may not be adequately sealed to prevent the mosquitoes’ entry. Once there is a large population of persons or animal hosts infected with agents (like dengue or West Nile virus), these illnesses can proliferate through these transmitting vector insects.” But could that be changing? The increasing temperatures and weather changes, which includes a rise in precipitation, could allow for a shift or an expansion of disease-carrying insects’ territory, says the Centers for Disease Control and Prevention. More research is needed to better predict if this will happen. Other factors attributed to the rise of transmitted vector-borne diseases include: ■M igratory birds that carry disease ■A n increase in the population of whitetailed deer, which carry disease transmitted by ticks ■H ome construction in formerly unin- How to avoid being bitten The best way to stop the spread of vector-borne infections is to prevent insect and tick bites in the first place. Follow these tips to avoid being exposed: ■ Remove outside sources of standing water that provide a breeding ground for mos- quitoes, such as birdbaths, planters and pet bowls. ■K eep window and door screens in good condition. ■K eep your yard free from piles of leaves, and mow the lawn often. ■A void wooded, brushy or grassy areas that may be tick-infested. ■D uring outdoor activities near where ticks and mosquitoes may live, wear light-colored clothing so you can easily see and remove ticks and insects. Wear long sleeves and long pants, tucking pant legs into your socks or shoes to cover skin. A hat helps, too. ■U se an insect repellent on your skin or clothing. Repellents recommended for their effectiveness include those containing DEET, picaridin, IR3535, permethrin and oil of lemon eucalyptus. Avoid clip-on and wristband devices since they may not be as effective as spray-on or rub-on DEET products. Use high-concentration DEET products with care because some may cause neurological problems. ■ Check your clothing and skin for ticks when you return indoors. Check pets, too. 4 June 2015 habited wilderness areas where more ticks and insects can be found ■ I nfected individuals who travel between regions ■A growing number of individuals with compromised immune systems, which makes them more susceptible to vectorborne infection Who’s most at risk? While reports of vector-borne infections being transmitted in the United States may garner media attention, such diseases aren’t always easily transmittable. Lyme disease spread by ticks, for example, has a low transmission risk overall—including in regions where Lyme is common. “Individuals at greatest risk of developing symptoms and infection-related complications include those who are 65 and older or have a weakened immune system,” Dr. Davis says. “Persons with chronic health conditions such as heart and kidney diseases or on immunosuppressant medications may experience more severe manifestations of disease.” You’re also more likely to become infected if you travel to regions where the diseases are more common. Below is a rundown of vector-borne diseases that may pose a risk—albeit usually slight—to residents of North America and Puerto Rico. ■ Mosquitoes West Nile virus usually pro- duces mild or no symptoms in healthy individuals. One in five people have flulike symptoms and skin rash. Sometimes fatigue and weakness can last for weeks or months. West Nile virus is usually treated with overthe-counter pain relievers, but patients with severe cases may be hospitalized to receive intravenous f luids and pain medication. In fewer than 1 percent of cases, patients develop encephalitis or meningitis. THINKSTOCK Not long ago, being bitten by a mosquito didn’t mean much more than having to deal with an itchy, swollen area of your skin. These days, if you take certain news reports to heart, a mosquito bite can leave you with an infection you may never have heard of until recently. Despite the alarmist nature of the news, your risk of contracting a vector-borne illness—infection spread by a bite from a tick, a mosquito or another insect—is quite low. But there is some truth behind the news. Worldwide, more than 1 billion people are infected, and more than 1 million die of diseases such as malaria and dengue fever, transmitted by mosquitoes, according to the World Health Organization. “Many insect-transmitted diseases like dengue are most common in tropical and subtropical countries that have lowerquality housing and inadequate diseaseprevention methods and healthcare,” says Steven G. Davis, M.D., FACP, an infectious disease consultant at Baylor Medical Center at Irving in Texas. “The environment in these areas has been most suitable for the proliferation of particular insect vectors. These insects that THINKSTOCK healthafter50 ® Chikungunya made the news last July when two Florida residents were locally infected by the virus, which is common in parts of Africa and Asia and has recently spread rapidly throughout the Caribbean. Most infections of Americans are travel related. Symptoms can include a fever, headache, rash, muscle pain and debilitating joint pain. They usually improve within a week except for joint pain, which may linger for months. Anti-inf lammatories can relieve symptoms. Unlike most mosquitoes, one of the species that transmits the chikungunya virus—called the Asian tiger mosquito—is active during the daytime. Dengue fever has been reported over the last 16 years in states such as Texas, Hawaii and Florida. It produces high fever; severe headache; severe eye pain; joint, muscle and bone pain; rash; and mild bleeding. It’s usually treated with acetaminophen, rest and fluids. Worsening symptoms that include vomiting, abdominal pain and breathing problems can cause circulatory system failure, shock and death if they’re not treated. Encephalitis—inf lammation of the brain—can cause flulike symptoms and lead to seizures, coma and death if not treated. Antivirals, anticonvulsants and corticosteroids are used to treat the virus, prevent seizures and reduce brain swelling. ■ Ticks Lyme disease is perhaps the best-known tickborne disease. A bull’s-eye rash is a telltale sign of infection, although it doesn’t appear in every infected patient. Other symptoms include fever, headache and fatigue. If the infection isn’t treated, it can spread to the joints. “Untreated Lyme disease can also affect the heart and nervous system, although it’s rarely ever fatal,” Dr. Davis says. If caught early, Lyme disease is highly treatable. Antibiotics are all that’s usually needed to make a full recovery. Rocky Mountain spotted fever produces a spotted rash, as the name implies, but this typically doesn’t show up until the sixth day or later following the onset of symptoms, and up to 15 percent of patients never develop a rash. Other symptoms include fever, nausea, vomiting, severe headache, muscle pain and lack of appetite. “People exposed to ticks in an endemic area require prompt administration of an antibiotic like doxycycline to prevent some tickborneassociated illnesses like Rocky Mountain spotted fever to progress to a life-threatening form of the disease,” Dr. Davis says. Colorado tick fever is so named because up to 15 percent of campers in Colorado have been exposed to the virus. The virus is found less often in other states. It’s characterized by a fever that comes and goes, rash, sensitivity to light and flulike symptoms. Self-treatment with a pain reliever is usually all that’s needed. The illness typically goes away on its own unless complications develop. Southern tick-associated rash illness, or STARI, transmitted by the lone star tick, is sometimes mistaken for Lyme disease since they both leave a red bull’s-eye mark. As with most other tick-transmitted diseases, f lulike symptoms are common. Doctors may treat the illness with antibiotics because of its resemblance to Lyme disease, although it’s not known whether antibiotics have any effect on STARI. STARI symptoms tend to be less severe than Lyme’s, and patients recover faster than those with Lyme disease. Babesiosis is transmitted by deer ticks. Most cases occur in the Northeast and upper Midwest. Healthy people who contract babesiosis have either no or flulike symptoms. Prescription drugs are available to treat the disease; most people with no symptoms don’t need treatment. Ehrlichiosis and anaplasmosis are emerging infectious diseases in the United States and other countries, says the National Institute of Allergy and Infectious Diseases, with 1,761 cases reported in 2010. Symptoms, if any, may resemble those of the flu and are treated with antibiotics. If severe symptoms aren’t treated, both diseases can be life threatening. Powassan encephalitis can cause symp- toms such as headache, fever, confusion, partial paralysis and coma. No specific treatment exists, but patients can benefit from intravenous fluids, respiratory support and drugs to reduce brain swelling. Tularemia appears in various ways, depending on how bacteria enter the body. Fever may be accompanied by skin ulcers, lymph-gland swelling, eye irritation or inflammation, sore throat, mouth ulcers, tonsillitis and, in rare cases, cough, chest pain and difficulty breathing. Antibiotics can treat tularemia. ■ Triatomine (kissing) bugs Chagas disease causes more disability and death in the Western hemisphere than any other parasitic disease. Chagas disease that’s transmitted by insect is confined to mostly rural areas in Mexico, Central America and South America. In this country, blood-sucking triatomine bugs—also called kissing bugs or cone-nose bugs—are found mostly in the south, but infections are rare. Early symptoms, if any, are similar to those of the flu and may include swelling around the bite or the eye area. Symptoms can last a few weeks or months, after which the disease goes into remission permanently or reappears years or decades later. At that time, 30 percent of infected individuals may develop serious or life-threatening heart or gastric complications. Drugs and other treatments are used to kill parasites in the blood and manage symptoms. Don’t forget Fido Humans aren’t the only ones who can suffer adverse health consequences related to insect bites. A mosquito bite can infect your dog with the larvae of the roundworm, triggering the life-threatening disease heartworm. The disease can lead to damage to major organs, including the heart and lungs. Symptoms of heartworm include fatigue, weight loss, persistent cough and, as the disease progresses, a swollen belly. Drugs are available to prevent or control the disease. June 2015 5