botulism Archives

October 11, 2024

Nearly 100,000 birds dead in botulism outbreak linked to climate change, water diversions

By Douglas Main

An ongoing outbreak of botulism, a bacterial illness that causes muscle paralysis, has killed more than 94,000 birds at Tule Lake National Wildlife Refuge in Northern California, the worst such outbreak at the lake ever recorded, according to federal scientists.

Affected birds often cannot control their muscles and often suffocate in the water, said biologist and ornithologist Teresa Wicks, with Bird Alliance of Oregon, who works in the area. “It’s a very traumatic thing to see,” Wicks said.

Though local in scale, the outbreak and catastrophic die-off are tied to global problems including declining wetlands, increasing demand for limited water resources, hydrological diversions, and a warming climate.

These kinds of outbreaks can happen around the world and the phenomenon seems to be on the rise, according to Andrew Farnsworth, a scientist at the Cornell Lab of Ornithology who studies bird migration.

“Given warming temperatures, droughts, then intense periods of rain followed by drying… the hallmarks of climate change are all over this,” Farnsworth said.

The pestilence is caused by a toxin produced by a specific type of bacteria (Clostridium botulinum) that thrives in the area’s warm, stagnant, low water levels. Botulism can also affect people, though no human cases have been reported in this instance. Other outbreaks have been reported around the world, but generally cause far fewer deaths. A botulism outbreak in 2020 caused by similar conditions killed an estimated 60,000 birds at Tule Lake.

The Klamath Basin, of which the refuge is a part, has been disrupted by man-made dams and irrigation canals for over a century. The developments and diversions eliminated more than 90% of the area’s wetlands.

Tule Lake is an ancient water body, whose levels swelled and ebbed, but always remained, for hundreds of thousands of years. Historically, the lake and nearby wetlands would fill with water during the winter rains. Now, the water supply comes almost entirely from irrigation canals.

September 13, 2024

New study finds potentially harmful pathogens traveling high in the atmosphere

By Douglas Main

A wide variety of fungi and bacteria, including E. coli and other potential human pathogens, have been found high in the atmosphere where they can travel for hundreds to thousands of miles before falling back to Earth, according to new research.

Air samples collected from between roughly a half mile and two miles in altitude (1 kilometer to 3 kilometers) near Tokyo, Japan, carried bacterial species known to be capable of causing health problems such as food poisoning and skin infections, researchers said.

The study, published this week in Proceedings of the National Academy of Sciences, reported that while most of the microbes detected were likely dead, testing confirmed more than ten species of microbes collected from high in the sky were alive. Those were particularly hardy strains, including several found to be antibiotic resistant. One of these, a type of ubiquitous bacteria not known to normally infect humans, was resistant to five different antibiotic drugs.

The discovery represents a “paradigm shift,” said Xavier Rodó, the study’s lead author and head of the health and climate program at the Barcelona Institute for Global Health. “From the public health standpoint it opens the door to really viewing the air and the atmosphere as an environment we need to pay attention to.”

The scientists used atmospheric measurements and computer models in concluding that most of the material found over Tokyo was coming from an agricultural region in northeast China, where row crops and livestock are raised. The study authors hypothesized that some of the bacteria, including the antibiotic-resistant ones, derived from sewage used to fertilize the land, and from the soil itself.

Widespread use of antibiotics with industrialized livestock production could plausibly introduce antibiotic resistance bacteria into the atmosphere as bits of soil and manure can be aerosolized and blow away on the wind, said David Smith, a NASA microbiologist who wasn’t involved in the study.

Besides microbes, the researchers also found significant quantities of many elements normally found in soil, such as sulfur and sodium, as well as aluminum, potassium, iron, and calcium.

They also detected zinc sulfate nanoparticles, which they hypothesized are coming from fertilizer use, as well as trace quantities of zirconium and hafnium, metals mined in China but not in Japan.