Warming Climate Could Shift Where Diseases Spread

Scientists are warning that climate change may help some infectious diseases move into new places and become harder to treat, according to reporting by Live Science. Infectious diseases are illnesses caused by germs, such as bacteria or viruses. The report connects warmer weather, drier soil, ticks, mosquitoes, and medicines used when people get sick. For someone in middle school, this is not only a health story. It is also a science story about ecosystems, which are communities of living and nonliving things, evolution, and cause and effect.

One part starts in a lab at Caltech, a science university in California. Researcher Xiaoyu Shan studied soil microbes, which are tiny living things in dirt. Some dishes of soil were muddy, and others were very dry. In the dry soil, the microbes were evolving, or changing over generations, to become more antibiotic resistant. Antibiotics are medicines that kill bacteria, and resistant bacteria can survive medicines that used to work.

The study, published in March, showed that drought conditions could help antibiotic-resistant bacteria become more common. A drought is a long time with too little water. Live Science notes that most antibiotic resistance is still driven by humans’ misuse of antibiotics. Misuse means using medicine in the wrong way. But the Caltech work raises another concern. Climate change could act as a selective pressure, which means a condition in the environment helps certain living things survive and reproduce more than others.

That matters because antibiotic-resistant bacteria are sometimes called superbugs, meaning germs that are hard to kill with normal medicine. If more of these bacteria are selected for in some places, doctors may have fewer easy options when people get infections. Live Science also points out that climate change does not affect health in only one way. It can stress supply chains, the systems that move goods from makers to users, and nutrition, which means getting the food and nutrients people need.

Another part of the story is about ticks and mosquitoes. These animals can spread vector-borne illnesses, which are diseases carried from one living thing to another by a vector, such as a tick or mosquito. In the United States, warmer temperatures can let some insects and arthropods survive longer each year and farther north. Arthropods are animals with jointed legs and hard outer bodies, including ticks and insects. The Centers for Disease Control and Prevention, the U.S. public health agency called the CDC, reported in April that emergency department visits for tick bites were the highest for that month since 2017.

Live Science gives several examples of diseases or health problems that may shift as these animals spread. Lyme disease is carried by black-legged ticks. West Nile virus is spread by mosquitoes. Alpha-gal syndrome is not an infection, but it is passed by the Lone Star tick and can cause an allergy to red meat that does not go away. Positive tests for antibodies to alpha-gal increased by 100 times between 2013 and 2024. Antibodies are proteins the body makes when it reacts to something it sees as a threat.

There is still uncertainty. Scientists do not know exactly how much tick-borne illness will change as the planet warms. The answer depends on many factors, including how often people spend time outdoors and what they do to avoid tick bites. Some illnesses may also be underreported, meaning not every case is counted. That uncertainty is important. It does not mean the risk is fake. It means scientists are still working out how big the risk is, where it will be greatest, and how communities should prepare.