Ah, those summer days. Long, lazy days of picnics, barbeques in the backyard, walks in the woods, swimming at the beach, and sunshine until 9:00 p.m. No school. No problems. No worries.
No worries? Wait! What about those mosquitoes? Those flies buzzing around your food? The ants crawling in a long line across the kitchen counter or the picnic table? And then there are the ticks. Well, they were all always there—the mosquitoes, flies, fleas, and ticks—all the insects of summer. But in recent years, insects have become more of a worry, a danger, than just an annoyance.
The number of people who have contracted diseases from mosquitoes, ticks, or fleas has more than tripled since 2004, the year the US Center for Disease Control and Prevention (CDC) started collecting more detail on insect-borne illnesses. The CDC collects data on at least 16 known diseases transmitted by insects. In a report issued on May 1, 2018, the CDC noted that at least nine new insect-borne diseases have been discovered or introduced onto the continental US in the past 15 years—many of them life-threatening.
Ticks are among the worst offenders; they can carry Lyme disease plus four or five other illnesses including one that makes its victims deathly allergic to meat. Eating a hamburger can cause severe indigestion, anaphylactic shock, or even death to those afflicted.
The Zika virus carried by mosquitoes arrived in Puerto Rico, Florida, and Texas in 2016. From there it began to spread across the country. Zika can cause horrific birth defects in babies including microcephaly (a tiny head) and various neurological problems. West Nile virus, which affects birds and horses as well as people, has become one of the most common mosquito-borne diseases in the United States. Chikungunya, a particularly nasty but usually not fatal flu-like illness, is also now occasionally found in the United States, though most cases occur among travelers to tropical areas such as the Caribbean. And Dengue fever, formerly confined to tropical areas such as Southeast Asia, has been detected in Florida and Texas as well as Hawaii.
What is the cause of this sharp rise in insect-borne illness? Warmer weather, longer seasons, and the ease of travel—both international and within the US—are the main culprits according to Lyle Petersen, the CDC director of vector-borne diseases. Warmer temperatures allow the insects to breed more, raising the population of insects in any given area. The earlier springs and later falls we’ve been having mean people are exposed for longer times.
Many insects have extended their geographic range, notably moving northward as the summers in northern states become warmer and longer. Animals carry the insects into new territories as do people and vehicles. Lyme disease used to be limited to the East Coast, now it is common in Midwestern states such as Michigan. The Eastern Shore of Maryland is one of the hotspots for Lyme and its co-factors.
International travel by both planes and ships brings in new insects and the insects carry their own cargo of viruses, spirochetes, and bacteria. Deliveries of fruits and vegetables from other states and other countries—so good for our health—can also deliver insects—not so good for our health.
Prevention and early diagnosis and treatment are key for all the insect-borne diseases. When outdoors, it’s recommended that you wear long sleeves, tuck shirts in, and pull socks over pants legs. White socks make it easier to see any insects. Check for ticks. Check yourself, your kids and your pets. A shower within two hours of any outdoor activity in areas likely to have ticks has been shown to reduce the risk. If a tick is found firmly attached and visibly swollen, it has probably been there over 24 hours. In those cases, research has shown that a preventative 3- to 4-day round of antibiotics significantly reduces the chances of infection.
Using insecticides such as Deet is also known to be helpful. Clothing treated with the chemical permethrin works well at repelling insects but be aware that while humans and dogs can generally tolerate this highly effective insecticide, cats are very sensitive to even small amounts of the chemical. Cats have died within hours of touching or licking clothing or surfaces treated with permethrin.
The increasing insect-threat is beginning to be taken seriously in many localities, though it is not clear yet what are the best policies and practices to reduce the problem or to treat affected individuals. At this point, people need to be aware and take precautions.
Sources for more information:
"Disease Cases from Infected Mosquitoes, Ticks, and Fleas Have Tripled in 13 Years"
"Insect-Borne Diseases Have Tripled. Here's Why."
"Illnesses from Mosquito, Tick, and Flea Bites Increasing in the US"
International Cat Care Organization
Title image: Pond at Pickering Creek Audubon Center, Talbot Co. Photo: Jan Plotczyk