The earth is getting warmer, on average—and that is leading to more cases of certain infectious diseases.
Here, three experts explain what you need to know now about three dangerous diseases on the rise…
Valley Fever: Growing Danger in the DUST
More than half of people who live in or travel to the dry areas of the country—parts of Arizona, California, Nevada, New Mexico, Texas and Utah—run the risk of being infected with Coccidioides, a fungus that lives in the soil.
Coccidioidomycosis, also known as valley fever, causes no symptoms in 60% of people who get it—the immune system eliminates the infection, and no harm is done. But 35% will develop pneumonia, and 5% will become extremely ill when the fungus travels to the brain, bones or other parts of the body. The disease kills more than 150 people a year.
You literally can catch valley fever from the wind. Summer winds that create dust storms scoop up fungal spores from the soil and shoot them downwind. A rainy winter promotes fungal growth and can increase infections the following summer and fall. The number of infections decreases during the wet seasons, then spikes upward in the hot months. You cannot catch the disease from someone who is sick with it.
Between 1998 and 2011, the total number of reported infections increased tenfold. Though valley fever is common in parts of California and the Southwest, infections in the last dozen years have been reported to the CDC from 28 states and the District of Columbia.
See a doctor if you have flulike symptoms—such as fever, a cough, chest pain, headache and fatigue—that don’t start to improve in about a week. Some patients will have painful red bumps on their chest, arms, back or lower legs. Symptoms usually start about one to three weeks after you have been exposed to the fungus.
Tell your doctor about recent travels. Even in areas where valley fever is common, only about 25% of patients get an accurate diagnosis, partly because the infection has symptoms common to other illnesses. The misdiagnosis rate is higher in areas where doctors don’t think to test for it.
Antifungal medications, such as fluconazole (Diflucan), will control the infection. You might need to take medications for about six months. More serious infections may require amphotericin B, an intravenous antifungal medication.
Ticks on the Move
People who live in the northeastern states are accustomed to checking their skin (and their pets) for ticks. It’s a routine that’s going to become more common in other states. The blacklegged tick that transmits Lyme disease is taking advantage of warmer temperatures. It has been reported in many parts of the US and is moving into areas where it wasn’t seen before, including the colder parts of Maine, Vermont and even Canada.
Other ticks are thriving, too. The American dog tick, for example, which transmits Rocky Mountain spotted fever, is found in every state. The Lone Star tick, found in the eastern and southeastern states, carries ehrlichiosis and tularemia.
The extreme weather that has been linked to climate change is a boon for ticks. The long summer droughts that are natural to some areas served to reduce tick populations. In recent years, some of the same areas have had shorter dry seasons or heavier-than-expected rains, which may have caused an uptick in ticks.
In some parts of the country, tick season appears to be starting earlier and ending later. It’s not merely that summers are getting warmer. Winters, on average, are less cold than they used to be. Warmer winters are known to allow tick populations to expand northward and to higher elevations.
Check for ticks. Check yourself, your children and your pets after spending time outdoors. To reduce risk on hikes, stay on trails. If you plan to leave the path, wear light-colored clothing to make ticks easier to spot. Wear long sleeves, and tuck long pants into your socks.
Also, use insect repellent containing DEET on exposed skin.
Know the symptoms. Tick-related illnesses often are accompanied by flulike symptoms such as fever, fatigue, and aches and pains. Lyme and other tick diseases also can cause distinctive rashes. See your doctor if you develop any of these symptoms, particularly if you develop flulike symptoms when it’s not flu season.
Most victims of tick-borne illnesses can be cured with antibiotics, particularly when the infection is detected and treated early.
Rare But Deadly Amoeba
This single-cell organism Naegleria fowleri is found in freshwater lakes, rivers, streams and hot springs. It is not found in the ocean or other bodies of saltwater. It rarely causes infection—but when it does, the infection is deadly.
This amoeba thrives in warm, untreated water and can survive in temperatures up to 115°F. It has been identified most often in southern states in the US.
But in 2010, a young girl was infected while swimming in a lake near her home in Minnesota-an area that’s typically too cold for the amoeba to survive. Cases also have been reported in Indiana and Kansas. Scientists aren’t sure if the warming of the planet has extended the amoeba’s range, but it is one possibility.
The infection is rare. Only 31 cases were reported in the US between 2003 and 2012.
What happens: The amoeba enters the body through the nose, usually when people are swimming or diving in contaminated water. It then travels to the brain, where it literally consumes brain tissue.
Symptoms start one to seven days after exposure. The disease progresses rapidly, and there are no effective treatments. The fatality rate is more than 99%.
The organism can cause infection only when it enters the nasal cavities. There is no risk from drinking a glass of water or from typical showering.
When swimming in warm freshwater lakes, rivers, ponds or streams, wear nose plugs or keep your head above water. Hold your nose shut, or use nose plugs when jumping or diving into the water.
If you use a Neti pot or a bulb syringe to flush congestion from your nose, always use boiled, properly filtered or sterilized water. Officials recently found Naegleria in a municipal water system in Louisiana, where it caused two deaths—in both cases, the patients had performed nasal flushing.