Common Summertime Infectious Diseases

June 17, 2022

This article was medically reviewed by Dr. Richard Krieger.

With the weather warmer and people gathering outdoors, summertime lends itself to sun, fun, and togetherness. The downside is that warmer conditions can contribute to the spread of common summertime infectious diseases.

Common Summertime Infectious Diseases

Because popular activities like hiking, camping, gardening, and picnicking can open the door to certain infections, it’s important for everyone to be aware of common infectious diseases to watch out for this summer. Although colds and flu are common, other infectious diseases are more prevalent during these months. In this blog, ID Care’s Dr. Richard Krieger discusses the viral and bacterial illnesses he sees most frequently in the summer months, including:

He encourages people to learn who is likely to contract these illnesses; how to avoid getting them through tick or mosquito bites, foodborne bacteria, or contact with respiratory or digestive secretions; and how the diseases should be diagnosed and treated. That way, people will know what to do if symptoms arise.

These diseases cause a range of different symptoms, including flu-like discomforts, digestive issues, rashes, and, rarely, neurological problems. Infectious disease specialists like those at ID Care diagnose and treat some of these illnesses with antibiotics, while others resolve themselves with supportive therapy such as rest and over-the-counter remedies. But an infectious disease doctor should be consulted if anyone suspects they may have been infected to ensure the best chances of recovery.

Summertime Infectious Diseases: Recognizing the Dangers

A key to understanding common summertime infectious diseases is knowing where they come from.

Ticks feed on blood, and if they have picked up ehrlichiosis, anaplasmosis, or Lyme disease — often by biting an infected animal — they can transmit these bacterial infections to humans. When a tick bites a human, its saliva enters the host’s body through the skin, and that can transmit the infection, particularly if the tick remains attached for more than 24 hours. Alternatively, mosquitoes can transmit West Nile virus with a single, quick bite if they have previously contracted the disease from an infected bird.

Ticks are found in wooded or grassy areas, particularly where brush is tall. “In regions of the U.S. that have freezing winters — such as New Jersey, where ID Care doctors practice — ticks and mosquitoes are much more active during the warmer months, which is why people are more likely to get insect-borne (also called vector-borne) diseases in the summer,” Dr. Krieger said.

Mosquitoes live in growing or cut vegetation, hollow logs, or under tarps and lay their eggs in standing water. Because they favor humid, hot weather, they are primarily active in the summertime in most American regions.

Food poisoning arises when people eat foods in which bacteria have grown due to improper cooking or refrigeration. This tends to happen more frequently in outdoor settings that lack kitchen appliances — for instance, at a picnic or on the hiking trail. People may get sick from the bacteria itself, as with salmonella, or from a toxin made by the bacteria, which is how botulism develops.

Warm-weather activities and conditions may also contribute to enterovirus infections, but it’s still a mystery why the incidence of this large and very common family of viruses — spread through respiratory droplets or digestive secretions — surges in summer months. “The trend with a variety of enteroviruses in the summer is similar to what we’re used to with the flu, which is more frequent in the winter,” Dr. Krieger said.

Top 3 Tips for Preventing Infectious Diseases This Summer

Short of avoiding all outdoor activities, it’s impossible to completely prevent exposure to summer’s top infectious diseases. But there are preventive measures that can help:

  • Avoid getting mosquito and tick bites. In addition to applying insect repellent, you can lower your risk of bites by wearing long pants and long sleeves outdoors. To avoid mosquito bites, avoid time outdoors at night. To avoid tick bites, tuck the bottom of your pants into your shoes or socks while outside and inspect your body after you’ve returned home.

    “Ticks are small, and their bites are painless, so it’s easy to overlook them,” Dr. Krieger said. “It’s a good idea to have someone help you check for ticks. You can’t see the top of your head, but ticks often attach there.”

  • Ensure proper refrigeration and cooking. “If you’re at a picnic or campsite, don’t eat anything that has been sitting out awhile or has been in the refrigerator too long before the outing,” Dr. Krieger said. “Reheating foods to a high enough temperature can help, as most bacteria are killed by heat; however, some toxins are not.”
  • Practice good hygiene. “At ID Care, we recommend that our patients follow the hygiene rules their mothers taught them: Stay away from people who seem to be sick with any illness and wash your hands well and often,” Dr. Krieger said. “This can help prevent not only enteroviruses but food poisoning. In addition, we’ve learned some things from the COVID-19 pandemic — wherever people are gathered, distancing and wearing a mask can help prevent the transmission of viruses.”

Common Summer Infections Have Distinct Symptoms

It’s important that everyone be familiar with the symptoms associated with summer infections because this sheds light on when to seek medical treatment.

Common summertime infections to watch out for include several with symptoms that are similar, as well as others with signs that are more distinct:

  • Ehrlichiosis/anaplasmosis, enterovirus, and West Nile virus share flu-like symptoms such as head and muscle aches, chills, and fever — typically mild in otherwise healthy people. Other mild symptoms of ehrlichiosis/anaplasmosis can include a rash, and enterovirus can generate a variety of rashes or blisters. While death is rare, elderly people with immune problems face a higher risk of severe disease that can cause longer-lasting neurologic symptoms: fevers, pneumonia, seizures, or coma.

    Severe symptoms of enterovirus can include pleurodynia, a non-damaging chest pain that is also called the “devil’s grip,” as well as heart inflammation, meningitis, or encephalitis. “This disease is especially dangerous late in pregnancy,” Dr. Krieger said, “because a woman who has it when she gives birth can pass it on to her baby, making the newborn very sick.”

    In people with severe West Nile virus, symptoms may last a long time after recovery and can include fatigue, memory problems, weakness, headaches, balance problems, and pneumonia. “With West Nile virus, the occasional rash is a good thing,” Dr. Krieger noted, “because it tends to signal that the patient will not experience severe neurological symptoms.”

  • Food poisoning is dreaded by many because it causes digestive disturbances: nausea, vomiting, and diarrhea, sometimes with fever and potentially followed by dehydration. Neurologic symptoms and death are possible, but rare.
  • Lyme disease symptoms appear in three stages. The first often includes a rash that begins at the site of a tick bite and expands to resemble a red, bull’s-eye ring or a growing blotch, sometimes accompanied by flu-like symptoms.

    Untreated Lyme disease is not fatal but can be debilitating, with stage two potentially bringing longer-term symptoms including forgetfulness, concentration problems, dizziness, limb weakness, heart rhythm disturbances, and arthritis.

    “Many patients worry about a third stage, chronic Lyme disease (CLD), but the jury is out on whether it exists,” Dr. Krieger said. “Chronic fatigue has been documented, but it’s not clear how frequent it is or whether it stems from Lyme disease or something else, such as depression or a nutritional deficiency.”

Understanding Common Summer Infections: From Diagnosis to Treatment

When considering common infectious diseases to watch out for this summer, important topics include the diagnostic process — which can hinge, in part, on how a disease is transmitted and the region in which it usually strikes — as well as treatment strategies.

Ehrlichiosis and Anaplasmosis: What Makes Them Tick

Previously considered one disease, doctors now know that ehrlichiosis and anaplasmosis are different infections with similar characteristics. Both are:

  • Caused by bacteria that enter a person’s cells and cause damage.
  • Spread by ticks, the same variety that carry Lyme disease, known as Ixodes scapularis, or deer, ticks.
  • Geography dependent, with the disease most prevalent where these ticks inhabit, including the northeast, southeast, and south-central parts of the U.S.
  • Easily diagnosable, with a blood test being the method of choice.
  • Treatable with oral antibiotics such as doxycycline.

Enterovirus: It’s All in the Family

Enteroviruses, the most common group of summer infections, are part of a large family of illnesses including poliovirus, coxsackievirus, and echovirus. Anybody can get an enterovirus if exposed to someone who has one. Also, people who had one virus in the family should know that they can easily contract another one.

Specific enteroviruses may be difficult to diagnose and have no treatments other than supportive therapies but are self-limited like a cold and will eventually go away.

Caring for People Who Have Food Poisoning

Food poisoning is often diagnosed retroactively, based on a patient’s accounting of symptoms. In toxin-based cases, treatment is unnecessary, as symptoms exhaust themselves in a matter of hours. However, those with foodborne bacterial infections that have entered the bowel will be very ill and may need antibiotics. People with food poisoning also may need treatment with fluids to address dehydration.

Why Lyme Disease is Difficult to Detect

Lyme disease is caused by infection with the bacteria Borrelia burgdorferi, part of the same family of infections as syphilis. This disease is tricky in that it mimics many other illnesses and must be properly diagnosed to be effectively treated.

A positive blood screen can be confirmed with a western blot test, but positive results only prove that a patient has had Lyme disease at some point over the years.

“Most people who think they have Lyme disease don’t,” Dr. Krieger said. “A positive test is helpful if a patient recalls recently having the tell-tale rash or spending time in a tick-infested environment. Combined with other symptoms, that could suggest that treatment is needed. But blood tests are most helpful if they are negative because they rule out the disease.”

Antibiotics are very effective when prescribed appropriately. Unfortunately, some doctors often prescribe them unnecessarily when they see a positive blood test and wrongly assume a patient has an active infection. Unnecessary treatment with antibiotics may cause some unwanted side effects.

West Nile Virus: A Recent Problem

“Until a few years ago, West Nile virus did not exist in the Western Hemisphere. It was present only in the Eastern Hemisphere: the Middle East, Asia, and Africa,” Dr. Krieger said. “With international travel now more frequent, the world has become much smaller, and the disease has made its way to this side of the Atlantic.”

Although it is diagnosable with a blood test, there is no antiviral treatment for West Nile virus, which is treated supportively.

How Does ID Care Help People with Summer Infections?

Seeking care from an infectious disease specialist like those at ID Care is key for people experiencing symptoms that might be linked with one of summer’s common infectious diseases.

That’s because ID Care doctors are experts at identifying hard-to-diagnose infections and properly treating them so that they don’t progress, even when the conditions are difficult to distinguish from each other due to similar symptoms. Also key is that these specialists are qualified to make informed decisions about whether treatment is really needed, thus avoiding the prescription of antibiotics for patients who don’t need them and could be harmed by their long-term use.

“We often see patients whose diagnoses would have been missed if they had not come to ID Care,” Dr. Krieger said. “Our team of more than 50 doctors is available to provide that expertise 24/7.”

In addition to caring for people in their 10 offices, ID Care doctors work with hospitals across New Jersey to treat patients who have more severe symptoms of summer’s common infectious diseases. Beyond these summer illnesses, doctors within ID Care are experts at preventing, diagnosing, and treating all kinds of infectious diseases, including those contracted during international travel and those that can benefit from treatment with outpatient infusion therapy. To schedule an appointment with an ID Care infectious disease doctor today, call 908-281-0610 or visit

Anaplasmosis, Ehrlichiosis, Foodborne Illnesses, Infectious Disease Blog, Lyme Disease, Richard, Krieger, Tick-Borne Diseases, West Niles Virus