Here’s how West Nile is spread — and what symptoms to look for after a mosquito bite
I attended the American Meteorological Society Broadcast Meteorology Conference in San Diego in June, during which I found one of the speakers particularly thought provoking.
Dr. Bruce Bekkar is a former obstetrician/gynecologist who delivered thousands of babies over his many decades of service.
He’s also a longtime Delmar surfer who’s seen firsthand profound changes along the Southern California coastline due to sea-level rise and its effects on the beaches and towering sandstone cliffs above them. But a few years ago, he came to realize that the most significant impact of global warming was to our health.
“The current human cost of climate change in America is not limited to the death tolls of headline-grabbing superstorms, floods and heatwaves,” he wrote. “Although extreme weather events are increasing, evidence now clearly connects our global warming to additional, more prevalent dangers including warmer average temperatures, worsening air pollution, new infectious agents, and acute and chronic stress.”
According to the National Weather Service, heat is responsible for more fatalities than all other severe weather events combined. Not surprisingly, the state of Arizona has the highest number of heat-related deaths in the United States.
“Every year during summer, Arizona tilts upward on its axis and pours down into San Diego. If you don’t believe me, just drive down any street in San Diego and you’ll be more likely to see more Arizona license plates than California,” he said.
Extreme heat days are expected to increase five- to tenfold in the next 40 years. But it’s not just the heat waves that are causing problems, but also warmer ambient temperatures that are problematic.
“Hospitalizations due to cardiac problems increase about 5 percent and respiratory conditions rise 6 percent for every day that is 10 degrees warmer than typical in Southern California,” he told us. “For example, a day with 80 degrees temperatures versus 70 degrees.”
Not only are hotter daytime temperatures challenging, but the warmer overnight conditions aren’t allowing people to cool off, adding significantly to their stress.
However, it just not the heat, but also the humidity. The human body cools off by sweating, and sweating doesn’t work very well when it’s muggy. The warmer the air, the more water vapor it can hold; consequently, relative humidity levels are expected to increase in the future.
Dr. Bekkar told us when he attended medical school back in the 1980s, he only spent two hours over four years on tropical infectious diseases because they were told they would never see them unless they moved to the lower latitudes toward the Earth’s equator.
Since the time he attended medical school, tropical infectious diseases have spread northward.
Today, many of these tropical diseases are now occurring in the United States. For example, the first case of West Nile virus in the country happened in the Midwest back in 1999 and has since spread west, north and eastward to most of America with the first occurrence in California in 2002.
Another tropical disease that seems to be propagating northward is Dengue fever. This illness is spread by the bite of a mosquito and was only found in the tropics. Unfortunately, it’s now been spotted in Florida and Texas.
Not only are diseases spreading in the atmosphere but also the ocean. A warmer ocean is producing a higher occurrence of red tides. The group of phytoplankton that produces red tides and even flashes of electric-blue bioluminescence when agitated are called dinoflagellates, which prefer warmer waters.
Red tides can create toxins. These red tides have nothing to do with the gravitational forces of the sun or moon but can turn vast expanses of the near-shore ocean environment to brick red or brown in color.
Mussels, clams, scallops and oysters are bivalve mollusks that filter vast amounts of water for their food through their gills. This allows their tissues to accumulate toxins from red tides that can cause diarrhetic shellfish poisoning. According to the Woods Hole Oceanographic Institution website, diarrhetic shellfish poisoning produces gastrointestinal symptoms, usually beginning within 30 minutes to a few hours after consumption of toxic shellfish. Although not fatal, the illness is characterized by incapacitating diarrhea, nausea, vomiting and abdominal pain.
Worse is domoic acid from diatoms, another type of phytoplankton/algae/red tide that can accumulate not only in bivalves but also in Dungeness and rock crabs and bait fish, such as anchovies and sardines. If you consume enough of this neurotoxin, you can develop amnesic shellfish poisoning. This toxin kills neurons in your brain responsible for short-term memory. If you live along the coast, you may have seen seabirds or marine mammals, such as sea lions that feed on these baitfish, suffering from domoic poisoning.
So why is Dr. Bekkar speaking about climate change? Even though it will get worse before it gets better, by reducing the amount of fossil fuels we burn, for example in automobiles, we will see a rapid increase in air quality that will improve everyone’s health. He’s passionate about leaving the earth in the same condition when he grew up for the future of the thousands of children he helped delivered.
I will be giving a presentation about climate change, and what it means for our local weather at ECOSLO’s Green Drinks event on from 5:30 to 7 p.m. Tuesday at 7 Sisters Brewing Co., 181 Tank Farm Road in San Luis Obispo. All are welcome, including families.