18
The Kilkenny Observer Friday 5 May 2023
kilkennyobserver.ie
News Science & Wellbeing La Niña is an oceanic phenomenon that results in below-average sea-surface temperatures in the central and eastern tropical Pacific Ocean, and lower average temperatures worldwide. La Niña has dominated Earth’s weather for the past three years. But now forecasters are predicting that, sometime between this summer and the end of the year, La Niña’s opposite extreme, El Niño, will take over. That seismic shift could have major implications for human health, and specifically the spread of disease. El Niño will increase temperatures and make precipitation more volatile, which in turn could fuel the spread of pathogencarrying mosquitoes, bacteria, and toxic algae. It’s a preview of the ways climate change will influence the spread of infectious diseases. “The bottom line here is that there are a range of different health effects that might occur in the setting of an El Niño,” Neil Vora, a physician with the environmental nonprofit Conservation International, told Grist.org, a non-profit, independent media outlet dedicated to stories about climate change. “That means we have to monitor the situation closely and prepare ourselves.” As with La Niña, the effects of an El Niño extend far beyond a patch of aboveaverage warmth in the Pacific. Parched regions of the world — like Chile, Peru, Mexico and the American Southwest — are often bombarded with rain and snow. Some other parts of the world, including the Northeastern U.S., the Amazon and Southeast Asia’s tropical regions, on the other hand, don’t see much rain at all in an El Niño year. The planet could temporarily become 1.5 degrees Celsius (2.7 degrees Fahrenheit) warmer, on average, than in preindustrial times — a threshold scientists have long warned
The link between poor sleep and worsening disease is one that researchers into Alzheimer’s disease are exploring in depth, with a new study finding that using sleeping pills to get some shut-eye could reduce the build-up of toxic clumps of proteins in fluid that washes the brain clean every night. Researchers from Washington University in St. Louis found people who took suvorexant, a common treatment for insomnia, for two nights at a sleep clinic experienced a slight drop in two proteins, amyloid-beta and tau, that pile up in Alzheimer’s disease. Though only short and involving a small group of healthy adults, the study is an interesting demonstration of the link between sleep and the molecular markers of Alzheimer’s disease. Sleep disturbances can be an early warning sign of Alzheimer’s disease that
As the planet shifts into an El Niño year, Barker said the areas to keep a close eye on are ones where moderate or heavy rains are followed by dry, warm months. If the past is any indication, countries like India and Pakistan are especially at risk. So is California. After years of drought, recent storms in the Golden State have generated a lot of flooding and cooler-than- normal conditions. If that leads into a hotter-thannormal summer, “that may set things up for bad conditions for West Nile virus,” Barker said of the mosquito-borne illness that is becoming more prevalent in the U.S. El Niño is projected to bring
unusual warmth to the Pacific Northwest and the northern Great Plains. Kristie L. Ebi, a professor of global health at the University of Washington, said warmth is often the determining factor in how far north vectors of disease move. “We know that mosquitoes don’t control their internal temperature,” she said. “When it’s hotter they’re going to see opportunities to move into new ranges. If the El Niño lasts long enough they get established and find habitat, then you can see an expansion in geographic range.” A study on the link between infectious disease in the U.S. and El Niño, published in 2016, found a link between tickborne illnesses such as rickettsiosis — an infection that can damage the brain, lungs and skin — and El Niño in the western US. Vibrio cholerae, the waterborne bacteria that causes cholera, is another area of concern, experts told Grist — both in areas that see more rain during El Niño and those that see less rain. Flooding aids the spread of the cholera bacteria from open sewers and other waste containers — still prevalent in many underdeveloped parts of the world — into drinking water systems. Drought also leads to an uptick in cholera cases in poor countries, because restricted access to fresh water forces people to use less water for personal hygiene practices like handwashing and turn to unsafe sources of drinking water. “Cholera can be a devastating infectious disease that causes a very severe diarrhoea that can dehydrate people so badly that they die,” Vora said. “In the setting of an El Niño extreme weather event, there might be impacts on sewage systems or on access to clean water, and that can lead to the spread of water-borne diseases such as cholera.”
zheimer’s to interpret it as a reason to start taking suvorexant every night,” says neurologist Brendan Lucey, of Washington University’s Sleep Medicine Centre, who led the research. The study spanned just two nights and involved 38 middle-aged participants who showed no signs of cognitive impairment and had no sleep issues. Using sleeping pills for prolonged periods is not an ideal solution for those short on sleep either, as it’s quite easy to become dependent on them. Sleeping pills may also lull people into shallower bouts of sleep rather than deep sleep phases. This could be problematic as earlier research from Lucey and colleagues found a link between less good quality, slow-wave sleep and elevated levels of tau tangles and amyloid-beta protein. In their latest study, Lucey and colleagues wanted to see if improving sleep with
the aid of sleeping pills could lower levels of tau and amyloid-beta in the cerebrospinal fluid that bathes the brain and spinal cord. Past research shows that even just one night of disrupted sleep can send amyloid-beta levels rising. A group of volunteers aged 45 to 65 years old received one of two doses of suvorexant or a placebo pill, an hour after researchers tapped their cerebrospinal fluid to collect a small sample. The researchers continued to collect samples every two hours for 36 hours while the participants slept and during the next day and night, to measure how protein levels changed. There were no differences in sleep between the groups, and yet amyloidbeta concentrations were reduced by between 10 and 20 percent with a dose of suvorexant usually prescribed for insomnia, compared to a placebo.
Shift in weather pattern concern for human health marks the difference between a tolerable environment and one that causes intense human suffering. These patterns are a boon for certain vector-borne illnesses — defined as infections transmitted by an organism (usually an arthropod, a category that includes insects and arachnids). Regions of the world that will experience longer wet seasons because of El Niño, many of which are in the tropics, may see an increase in mosquito-borne illnesses, according to Victoria Keener, a senior research fellow at the East-West Centre in Honolulu, Hawaii, and a coauthor of the upcoming Fifth National Climate Assessment.
“El Niño will mean a longer breeding season for a lot of vectors and increased malaria potential in a lot of the world,” she said. A 2003 study on the intersection of El Niño and infectious disease showed spikes in malaria along the coasts of Venezuela and Brazil during and after El Niño years. The study looked at more than a dozen cycles between El Niño, La Niña, and the cycle’s “neutral” phase, which taken together are known as the El Niño-Southern Oscillation, or ENSO. The researchers, who analysed data dating back to 1899, also found an increase in malaria during or post-El Niño in Colombia, India, Paki-
stan and Peru. Cases of dengue, another mosquito-borne illness, increased in 10 Pacific islands. The manner in which El Niño impacts mosquitos and the diseases they carry is varied and often difficult to accurately calculate, said Christopher Barker, an associate professor in the Department of Pathology, Microbiology and Immunology of the University of California Davis School of Veterinary Medicine. Mosquitos breed in warm, wet conditions. But too much water in the form of flooding rains can wash away mosquito larvae and ultimately contribute to a decrease in mosquito populations.
Sleep tablets may ward off Alzheimer’s precedes other symptoms, such as memory loss and cognitive decline. And by the time the first symptoms develop, levels of abnormal amyloid-beta are almost peaking, forming clumps
called plaques that clog up brain cells. Researchers think promoting sleep could be one avenue to stave off Alzheimer’s disease, by allowing the sleeping brain to flush itself
of leftover proteins and the day’s other waste products. While sleeping pills may help in that regard, “it would be premature for people who are worried about developing Al-
