4 infectious diseases to watch out for this summer

By Alistair Gardiner
Published June 28, 2021

Key Takeaways

After a rough year of social isolation and pandemic anxiety, we all deserve a little time outdoors this summer. But before you head out for a BBQ or a swim at the lake, take heed of some common non-COVID-19 infections and diseases that can put a serious damper on summer fun.

From foodborne illnesses to those transmitted through insect bites, here are four infectious diseases you should bear in mind as you venture out this summer. 

Giardia and norovirus 

For some, the summer means plenty of trips to pools, water parks, and natural swimming areas. Unfortunately, public swimming pools are one of the primary breeding grounds for infections such as giardia that boast some very unpleasant symptoms, according to the Mayo Clinic.

The crew of NBC’s television series Ultimate Slip N’ Slide learned this the hard way, when 40 of them caught giardia at a water park. Media reports of the incident, which led to a temporary production shut down, described the “awful explosive diarrhea” experienced by dozens of crew members. 

Giardia infection (also known as giardiasis) is an intestinal infection caused by a microscopic parasite, which is typically found in backcountry streams and lakes, swimming pools, whirlpool spas, and wells. Infections usually last 2-6 weeks but can cause long-term intestinal issues. 

Symptoms of the infection, which typically appear 1 to 3 weeks after exposure, include watery diarrhea, stomach cramps and bloating, gas, nausea, weight loss, and fatigue. If you have these symptoms for longer than a week, it’s time to consider you might have giardia.

There is no drug or vaccine to prevent giardia, and while there are some medications to treat the infection, not everyone responds to them, so the best plan is to prevent catching it in the first place. Infections most commonly occur by swallowing contaminated water, eating infected food, or through person-to-person contact (people who change diapers, care workers who handle feces, or people who engage in anal sex are the most at risk). Mayo Clinic experts suggest washing hands, drinking bottled water, and trying to keep your mouth closed in swimming in pools, rivers, or lakes, to protect against giardia.

Another nasty bug that can ruin summer fun is the norovirus, which can be transmitted by consuming contaminated food or water, having contact with an infected person, or touching contaminated surfaces.

According to the CDC, norovirus causes inflammation of the stomach and intestines and can lead to symptoms similar to giardia, including vomiting and diarrhea. Proper hand hygiene is your best defense. And we all ought to be experts in that by now, given that we’ve all had a lot of practice with washing and sanitizing our hands over the past year and a half.

Food poisoning 

Barbecues are a staple of summer but bear in mind that without proper precautions, food poisoning may lurk in your favorite foods.

According to UrgentMED, summer cookouts are a prime spot to find the latest strains of bacteria like E.coli, salmonella, and campylobacter, all of which cause food poisoning. Typical symptoms include stomach cramps, vomiting, nausea, and diarrhea. While most food poisoning isn’t deadly, infection with E. coli can be—around 5%-10% of people infected develop life-threatening complications within 3-4 days of showing symptoms, according to UrgentMED.

Food poisoning is more common in the summer months because heat allows bacteria to flourish on any food, dish, or drink that’s not covered and kept cool, so be sure to keep your food refrigerated and stored away until you’re cooking it. Washing everything thoroughly—including surfaces, utensils, and produce—is important in helping prevent food poisoning. Experts do not recommend washing raw chicken, however—the water splashed onto the sink and counters can spread germs, increasing the risk of becoming infected with salmonella or another foodborne germ.

Beyond that, you should also keep a meat thermometer handy, so you can cross-check the temperature of any meat cooked on a BBQ with a meat temperature chart prior to consumption. For example, poultry should be cooked to an internal temperature of 165 degrees in order to kill any germs, and any fresh pork needs to reach a temperature of 145 degrees. 

Lyme disease

Lyme disease, which is about to hit its peak season, is America’s most common vector-borne disease, according to the CDC. It’s transmitted to people through the bite of infected black-legged ticks and can result in fever, headache, fatigue, and a skin rash. If left untreated, symptoms can occur days and even months after the bite, and include facial paralysis, painful and swollen joints, heart palpitations, episodes of dizziness, and inflammation of the brain and spinal cord, among others.

While most cases of Lyme disease can be treated with a few weeks of antibiotics, it’s best to avoid infection in the first place. The CDC suggests that you research whether there are ticks present in any areas before you head out hiking or camping. You can also use insect repellents on skin or clothes before heading out into the wilderness. If you want to be really careful, you can avoid wooded and brushy areas with high grass and leaf litter, and stick to the center of trails and paths.

When you return home, always check your skin, clothes, and pets for ticks. You should pay particular attention to under the arms, the back of the knees, inside the navel, and around the ears. If you find a tick, the CDC has instructions on the safest and most effective way to remove them here.

Roughly 30,000 cases of Lyme disease are reported to the CDC by state health departments annually, but the agency estimates that roughly 476,000 people may get Lyme disease each year in the United States.

Click here to read about other tick-borne illnesses at MDLinx.


Another virus that thrives in the summer is the coxsackievirus, a form of enterovirus that can cause hand, foot, and mouth disease (HFMD), along with diseases of the muscles, lungs, and heart.

HFMD most commonly occurs in children but can affect adults as well. The virus spreads from contact with people or surfaces contaminated by infected feces—usually in the summer and fall. HFMD can cause mild flu-like symptoms, including fever, malaise, sore throat, rashes, and red blisters on the hands and feet, or painful ulcers in the mouth and throat. The symptoms tend to resolve without treatment in about 10 days.

But HFMD, and other forms of coxsackievirus, can lead to serious conditions including viral meningitis, encephalitis, or even myocarditis. Pay heed to persistent diarrhea, fever, or vomiting, or if a person begins exhibiting symptoms such as convulsions, difficulty breathing, or pain in one or both testicles.

The best protection is frequent hand-washing, and avoiding contact with individuals with HFMD, along with their stool, saliva, or blister fluid. 

Enjoy the summer, but stay safe

So, don’t shut yourself in this summer; go enjoy some outdoor time and soak up some sun (responsibly, of course). Just remember to wash your hands and keep an eye out for ticks.

Of note, infections are not the only health hazards associated with this season. Read These dangerous conditions are caused by summer heat at MDLinx.

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