Global Warming’s Impact on Your Health

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FLU SYMPTOMS—fatigue, cough, aches and fever—these days create fears of the circulating coronavirus, particularly among travelers to China and northern Italy.  But for travelers and those living in the West—or Mexico or South America—an increasingly likely diagnosis is Valley Fever, caused by a fungus carried by desert dust.

In fact, climate change may wreak its worst havoc on human health by way of airborne organisms, which are increasing with hotter, drier lands and warmer waters.

In drier regions of the country, Valley Fever has been on “a steady climb” over the past two decades—mostly in western states, including New Mexico, Texas and Nevada, with the highest numbers in Arizona and California, according to pulmonologist Michael Peterson at UCSF Fresno.

“It’s hard to be a doctor in Fresno and not have to deal with Valley Fever,” Peterson said.  According to some predictions, “a warming climate will allow Valley Fever to expand throughout much of the western United States” by 2100. Even now, many people diagnosed with pneumonia in those regions may have Valley Fever, meaning many thousands more cases than official totals—15,611 in 2018, with more than half in California.

Besides flu-like symptoms, Valley Fever can cause a rash of painful red bumps on the lower legs, chest and back. The disease can resolve without treatment or can progress to a chronic form of pneumonia, most often in people with weakened immune systems.

The most serious outcome, disseminated coccidioidomycosis, causes nodules, ulcers and skin lesions throughout the body that are sometimes mistaken for cancer; painful joints; and meningitis, infecting membranes of the nervous system, including the brain.

Those most prone to develop serious infection are people of African-American and Filipino heritage, with African-Americans 10 times more likely and Filipinos 175 times compared to Caucasians—making susceptibility most likely genetic for these groups.  Other populations at risk include those over 60 or with weakened immune systems, for example, living with HIV-AIDS.

“We actually know much less about fungal pathogens than we do about other types of microbial pathogens,” explains UCSF microbiologist Anita Sil. Coccidioides immitis is a class of soil fungi that can shape-shift inside the host, in one phase growing larger than the immune cells that would normally destroy harmful microbes. “These fungi…become attuned to manipulating the human immune response and are really very good at surviving long-term in the human body,” according to Sil.

Another airborne threat, smoke from worsening wildfires contains gases as well as particles from burning trees that can impair lung function and worsen chronic lung and heart disease. Despite advice to residents to stay indoors and use indoor air filters and, when outdoors, to wear medical-grade masks, health risks from smoke are difficult to avoid—even for those living many miles from the fires.

The EPA’s “good air quality” upper limit for microscopic particulate pollution, called PM 2.5, is 12 micrograms per cubic meter.  Particulate pollution after the Camp Fire in California last year rose to the “very unhealthy” level of 200—and levels in Bethesda, Maryland, on its worst day of 2019, rose to 38.

For those living or vacationing near oceans and lakes, red tides and blue-green algae blooms linked to global warming send toxins into the air that risk damaging the lungs, liver and nervous system. While Florida has had the worst outbreaks in recent years, blue-green algae has appeared in the Chesapeake Bay, New England and elsewhere.

Following last year’s several months-long spike in blue-green algae levels in Florida, scientists detected cyanobacteria toxins (associated with liver cancer and neurogenerative diseases like Parkinson’s) more than a mile inland, according to marine biologist Mike Parsons at Florida Gulf Coast University, interviewed for the video series “Protect Your Water.”

“Makes you wonder if other waterborne pathogens can aerosolize, like PFAS, glyphosate, atrazine,” says one of the video producers. “We know enteric bacteria does—you can smell it.”

PFAS, fluorinated chemicals used in consumer products including fire-retardants and nonstick pans, may cause prenatal health issues, high cholesterol and immune system dysfunction.  These chemicals have shown up in the drinking water of dozens of U.S. cities and are widespread in rainwater.

Glyphosate, the primary ingredient in the weed killer Roundup and linked to hormone disruption, has made its way into the majority of U.S. rivers and streams and appears in about 70% of rainfall samples. Atrazine is the more toxic herbicide ingredient that glyphosate was designed to replace.

Another airborne threat, microplastics—from tires, textiles and personal care products—have dispersed in oceans and snow from the Arctic to the Alps and can cause lesions in the respiratory system especially harmful to those with existing lung problems.

Efforts to reverse global warming with the hope of reducing air- and water-borne health risks often looks like one step forward followed by a giant step back.  But spreading awareness about risky microorganisms, chemicals and microplastics can help with diagnosing specific health issues—and may boost motivation among individuals to play their part in combating climate change.

Mary Carpenter

Every Tuesday, well-being editor Mary Carpenter delivers health news you can use