Summer isn’t over yet — and neither is mosquito season, which means you still have a very real chance of catching West Nile virus. In fact, every year, cases of this virus typically peak in late August to early September, according to the Centers for Disease Control and Prevention (CDC). And the rise in cases has already started — in recent weeks, cases have been reported in 24 states, according to the CDC’s tracking website.
“Early data on weather patterns (and surveillance data suggest we may see the highest infection numbers [of West Nile virus] since the early 2000s,” says Dr. Jagdish Khubchandani, a professor of public health at New Mexico State University.
West Nile virus is most commonly spread to people through bites from an infected mosquito. And while Cleveland Clinic reports that most people who get infected don’t develop any symptoms, some do experience a mild, flu-like illness, while a smaller percentage can develop severe illness that requires hospitalization. With no vaccine or specific treatment available, prevention is key.
Below, we break down what you need to know about West Nile virus — including the symptoms to watch for and the best products on the market to protect yourself and your family from mosquito bites this season.
Related
Want more from NBC Selected? Sign up for our newsletter, The Selection, and shop smarter.
What is West Nile virus and how do you get it?
West Nile virus is most commonly spread to people through the bite of an infected mosquito. Research from the American Society of Microbiology states that mosquitoes pick up the virus after feeding on infected birds, then pass it along to people (and other animals) through subsequent bites. Each year, about 2,000 people in the U.S. are diagnosed with West Nile virus, though this is likely an undercount, since most people who get infected never develop symptoms or attribute mild ones to something else, according to the CDC. Mosquito season generally runs from June through October, with West Nile cases typically peaking in late August to early September.
While a mosquito bite is by far the most common way people get infected, it’s not the only one: In rare cases, West Nile virus can also spread through blood transfusions and organ transplants or from a mother to a baby during pregnancy, delivery or breastfeeding, according to Cleveland Clinic.
What are the symptoms of West Nile virus?
Most people who get infected with West Nile virus don’t develop any symptoms at all. But the CDC reports that about 20 percent of people will experience a fever along with other flu-like symptoms, sometimes referred to as West Nile fever. Symptoms typically show up two to six days after a bite, though it can take as long as 14 days before someone begins to feel ill. In rare cases — in less than 1 percent, to be exact — the virus can affect the brain or spinal cord, leading to more serious complications like encephalitis or meningitis.
The Mayo Clinic reports that the most common symptoms of West Nile virus include:
- Fever
- Headache
- Muscle aches
- Nausea and vomiting
- Diarrhea
- Rash, usually concentrated around the chest and back
- Swollen lymph nodes
- Sore throat
- Pain behind the eyes
Why does West Nile virus peak in August?
The timing comes down to biology. According to research published in the Journal of Medical Entomology, warm summer temperatures speed up mosquito larvae development, which drives mosquito populations up through the early and midsummer months. At the same time birds are laying and hatching lots of eggs and nestlings and fledglings create prime ways for mosquitoes to pick up the virus, according to Johns Hopkins Bloomberg School of Public Health.
By the time case counts rise in July and peak in August, with a plateau into September, mosquito populations are at their most active and infectious — before the cooler weather in October causes both mosquito activity and case numbers to drop off. In other words, late summer is the window when infected mosquitoes, warm weather and human outdoor activity all overlap, making it the riskiest stretch of the year for exposure.
The best products for reducing the risk of West Nile virus
The best defense against West Nile is simply avoiding mosquito bites in the first place. That means taking preventive measures to avoid getting bitten. “First, remember the peak activity times of mosquitoes — early morning and early evenings — and try to avoid going out at these times,” says professor Khubchandani. “Second, use quality insect repellants, especially during these times.” Khubchandani also suggests staying vigilant about your outdoor spaces — if you see a lot of mosquitoes around you, look to address the issue with products like mosquito dunks (more on those below).
Below, I’ve rounded up a few mosquito repellent products — including repellents and other items that will help you manage mosquitoes in your space — that experts have previously recommended to NBC Selected as good ways to ward off mosquitoes.
Experts previously recommended these mosquito dunks as an effective way to prevent mosquitoes from taking over your home. Mosquito dunks are small round rings that you put in water — think ponds, bird baths and any other body of standing water. They work by releasing natural bacteria into the water. When mosquito larvae hatch, they eat the floating bacteria and the toxins kill them within 48 hours, according to the brand. Also helpful to know: These dunks aren’t toxic to other animals and they last for 30 days.
This device essentially builds an invisible barrier around a small area to keep mosquitoes away. It’s rechargeable and disperses a repellent that works within a 20-foot radius, according to the brand. The device comes with a USB-C charging cable and several repellent cartridges, each providing up to 12 hours of protection. My 1-year-old son reacts terribly to mosquito bites — I’m talking huge welts that blister and swell — so we have one of these on our front porch and another on the back porch and they keep our home free from the biting pests.
Gootop’s Outdoor Bug Zapper can be hung from a patio awning or set on a table, ledge, or other flat surface. It works by emitting a blue light that draws in flying insects, then zaps them once they get close, helping clear the area of flies, mosquitoes, gnats, wasps and more. According to the brand, a single unit can cover up to half an acre. Cleanup is simple, too: Dead bugs collect in a removable tray at the base, which can be wiped out with the included brush. The zapper has racked up nearly 20,000 five-star ratings, with reviewers praising how easy it is to hang and how effectively it clears insects from their space.
This unscented body repellent spray is designed to guard against ticks and mosquitoes using a 30 percent concentration of DEET, which experts have previously told us is the most effective ingredient in bug sprays for repelling mosquitoes. The formula is water-based rather than alcohol-based, which helps more of the product stay on the skin instead of evaporating during application, according to the brand. Its spray nozzle also releases a continuous mist, making it easy to cover exposed areas, including harder-to-reach spots like your back.
This repellent is formulated with 20 percent picaridin, a popular alternative to DEET that offers comparable effectiveness while typically feeling less greasy on skin and being gentler on fabrics. According to the company, this formula provides up to 12 hours of protection against mosquitoes and ticks, and eight hours against flies, gnats and chiggers. This is my go-to for my daughter, who goes to summer camp in the forest. I spray her down every morning and she’s never come home with a mosquito bite or tick.
Related
Frequently asked questions
The vast majority of people infected with West Nile virus — roughly 80 percent, according to the CDC — never develop any symptoms at all. About one in five experience a mild, flu-like illness, while fewer than 1 percent go on to develop a serious infection affecting the brain or nervous system.
If symptoms do develop, they typically emerge two to 14 days after a bite from an infected mosquito, starting with sudden fever, headache, body aches and pronounced fatigue, according to the CDC.
If you develop symptoms like fever, headache or body aches after spending time outdoors, it’s worth checking in with a healthcare provider, especially if you know you’ve been bitten by mosquitoes recently. There’s no specific treatment for West Nile virus disease, so for mild illness, doctors typically recommend the same at-home care you’d use for a cold or flu — rest, fluids and pain medications to relieve symptoms, according to the CDC.
If you experience warning signs of more serious illness — think high fever, neck stiffness, muscle weakness, confusion or tremors — don’t wait it out at home. Head to the emergency room right away, since these can be signs that the virus has affected your brain or spinal cord and may require hospitalization, advises the CDC.
Meet our public health expert
At NBC Selected, we work with experts with specialized knowledge and authority based on relevant training or experience. We also ensure all expert advice and recommendations are made independently and without undisclosed financial conflicts of interest.
- Dr. Jagdish Khubchandani is a professor of public health at New Mexico State University.
Why trust NBC Selected?
I am a commerce editor at NBC Selected and a journalist who regularly covers wellness, beauty, and lifestyle. I have written about relieving shoulder pain and whether or not makeup wipes are bad for you. For this story, I gathered information from NBC News and the CDC, and spoke with a public health expert about West Nile virus.
Catch up on NBC Selected’s in-depth coverage of tech and tools, wellness and more, and follow us on Facebook, Instagram, Twitter and TikTok to stay up to date.
