Wildfires ignite infection risks, by weakening the body’s immune defences and spreading bugs in smoke

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Over the past several days, the world has watched on in shock as wildfires have devastated large parts of Los Angeles.

Beyond the obvious destruction – to landscapes, homes, businesses and more – fires at this scale have far-reaching effects on communities. A number of these concern human health.

We know fire can harm directly, causing injuries and death. Tragically, the death toll in LA is now at least 24.

But wildfires, or bushfires, can also have indirect consequences for human health. In particular, they can promote the incidence and spread of a range of infections.

Effects on the immune system

Most people appreciate that fires can cause burns and smoke inhalation, both of which can be life-threatening in their own right.

What’s perhaps less well known is that both burns and smoke inhalation can cause acute and chronic changes in the immune system. This can leave those affected vulnerable to infections at the time of the injury, and for years to come.

Burns induce profound changes in the immune system. Some parts go into overdrive, becoming too reactive and leading to hyper-inflammation. In the immediate aftermath of serious burns, this can contribute to sepsis and organ failure.

Other parts of the immune system appear to be suppressed. Our ability to recognise and fight off bugs can be compromised after sustaining burns. Research shows people who have experienced serious burns have an increased risk of influenza, pneumonia and other types of respiratory infections for at least the first five years after injury compared to people who haven’t experienced burns.

Wildfire smoke is a complex mixture containing particulate matter, volatile organic compounds, ozone, toxic gases, and microbes. When people inhale smoke during wildfires, each of these elements can play a role in increasing inflammation in the airways, which can lead to increased susceptibility to respiratory infections and asthma.

Research published after Australia’s Black Summer of 2019–20 found a higher risk of COVID infections in areas of New South Wales where bushfires had occurred weeks earlier.

We need more research to understand the magnitude of these increased risks, how long they persist after exposure, and the mechanisms. But these effects are thought to be due to sustained changes to the immune response.

Microbes travel in smoky air

Another opportunity for infection arises from the fire-induced movement of microbes from niches they usually occupy in soils and plants in natural areas, into densely populated urban areas.

Recent evidence from forest fires in Utah shows microbes, such as bacteria and fungal spores, can be transported in smoke. These microbes are associated with particles from the source, such as burned vegetation and soil.

There are thousands of different species of microbes in smoke, many of which are not common in background, non-smoky air.

Only a small number of studies on this have been published so far, but researchers have shown the majority of microbes in smoke are still alive and remain alive in smoke long enough to colonise the places where they eventually land.

How far specific microbes can be transported remains an open question, but fungi associated with smoke particles have been detected hundreds of miles downwind from wildfires, even weeks after the fire.

So does this cause human infections?

A subset of these airborne microbes are known to cause infections in humans.

Scientists are probing records of human fungal infections in relation to wildfire smoke exposure. In particular, they’re looking at soil-borne infectious agents such as the fungi Coccidioides immitis and Coccidioides posadasii which thrive in dry soils that can be picked up in dust and smoke plumes.

These fungi cause valley fever, a lung infection with symptoms that can resemble the flu, across arid western parts of the United States.

A study of wildland firefighters in California showed high rates of valley fever infections, which spurred occupational health warnings including recommended use of respirators when in endemic regions.

A California-based study of the wider population showed a 20% increase in hospital admissions for valley fever following any amount of exposure to wildfire smoke.

However, another found only limited evidence of excess cases after smoke exposure in wildfire-adjacent populations in California’s San Joaquin Valley.

These contrasting results show more research is needed to evaluate the infectious potential of wildfire smoke from this and other fungal and bacterial causes.

Staying safe

Much remains to be learned about the links between wildfires and infections, and the multiple pathways by which wildfires can increase the risk of certain infections.

There’s also a risk people gathering together after a disaster like this, such as in potentially overcrowded shelters, can increase the transmission of infections. We’ve seen this happen after previous natural disasters.

Despite the gaps in our knowledge, public health responses to wildfires should encompass infection prevention (such as through the provision of effective masks) and surveillance to enable early detection and effective management of any outbreaks.

Christine Carson, Senior Research Fellow, School of Medicine, The University of Western Australia and Leda Kobziar, Professor of Wildland Fire Science, University of Idaho

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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  • 10 Simple Japanese Habits For Healthier & Longer Life

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    You don’t have to be Japanese or live in Okinawa to enjoy the benefits of healthy longevity. A lot of it comes down to simple habits:

    Easy to implement

    We’ll not keep the 10 habits a mystery; they are:

    1. Start the day with hot water: drinking hot water in the morning helps with hydration, warming the body, and aiding digestion.
    2. Enjoy a hearty breakfast: Japanese breakfasts are traditionally filling, nutritious, and help promote energy and longevity. Typical components include rice, miso soup, fish, and pickles.
    3. Take balanced meals: Japanese education emphasizes nutrition from a young age, promoting balanced meals with proteins, fiber, and vitamins & minerals.
    4. Enjoy fermented foods: fermented foods, such as nattō and soy-based condiments, support digestion, heart health, and the immune system.
    5. Drink green tea and matcha: both are rich in health benefits; preparing matcha mindfully adds a peaceful ritual to daily life too.
    6. Keep the “80% full” rule: “hara hachi bu” encourages eating until 80% full, which can improve longevity and, of course, prevent overeating.
    7. Use multiple small dishes: small servings and a variety of dishes help prevent overeating and ensure a diverse intake of nutrients.
    8. Gratitude before and after meals: saying “itadakimasu” and “gochisousama” promotes mindful eating, and afterwards, good digestion. Speaking Japanese is of course not the key factor here, but rather, do give yourself a moment of reflection before and after meals.
    9. Use vinegar in cooking: vinegar, often used in sushi rice and sauces like ponzu, adds flavor and offers health benefits, mostly pertaining to blood sugar balance.
    10. Eat slowly: Eating at a slower pace will improve digestion, and can enhance satiety and prevent accidentally overeating.

    For more on all of these, enjoy:

    Click Here If The Embedded Video Doesn’t Load Automatically!

    Want to learn more?

    You might also like to read:

    How To Get More Out Of What’s On Your Plate

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  • Fiber Fueled – by Dr. Will Bulsiewicz

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    We generally know that for gut health we should eat fiber, but what of the balances of different sorts of fiber?

    That’s one of the main things that make this book stand out—fostering diversity in our microbiome by fostering diversity in our diet. Specifically, diversity of fiber-containing foods.

    The book is part “science made easy for the lay reader”, and part recipe book. The recipes come with shopping lists and a meal planner, though we would recommend to use those as a guide rather than to try to adhere perfectly to them.

    In particular, this reviewer would encourage much more generous use of healthful seasonings… and less reliance on there being leftovers several days later (tasty food gets gone quickly in this house!)

    As for the science, the feel of this is more like reading a science-based observational documentary with explanations, than of reading a science textbook. Studies are mentioned in passing, but not dissected in any detail, and the focus is more on getting the key learnings across.

    Bottom line: if you’d like to boost not just the amount, but also the diversity, of fiber in your diet, and reap the gut-health rewards, this book is a great guide for that!

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  • The BAT-pause!

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    When Cold Weather & The Menopause Battle It Out

    You may know that (moderate, safe) exposure to the cold allows our body to convert our white and yellow fat into the much healthier brown fat—also called brown adipose tissue, or “BAT” to its friends.

    If you didn’t already know that, then well, neither did scientists until about 15 years ago:

    The Changed Metabolic World with Human Brown Adipose Tissue: Therapeutic Visions

    You can read more about it here:

    Cool Temperature Alters Human Fat and Metabolism

    This is important, especially because the white fat that gets converted is the kind that makes up most visceral fat—the kind most associated with all-cause mortality:

    Visceral Belly Fat & How To Lose It ← this is not the same as your subcutaneous fat, the kind that sits directly under your skin and keeps you warm; this is the fat that goes between your organs and of which we should only have a small amount!

    The BAT-pause

    It’s been known (since before the above discovery) that BAT production slows considerably as we get older. Not too shocking—after all, many metabolic functions slow as we get older, so why should fat regulation be any different?

    But! Rodent studies found that this was tied less to age, but to ovarian function: rats who underwent ovariectomies suffered reduced BAT production, regardless of their age.

    Naturally, it’s been difficult to recreate such studies in humans, because it’s difficult to find a large sample of young adults willing to have their ovaries whipped out (or even suppressed chemically) to see how badly their metabolism suffers as a result.

    Nor can an observational study (for example, of people who incidentally have ovaries removed due to ovarian cancer) usefully be undertaken, because then the cancer itself and any additional cancer treatments would be confounding factors.

    Perimenopausal study to the rescue!

    A recent (published last month, at time of writing!) study looked at women around the age of menopause, but specifically in cohorts before and after, measuring BAT metabolism.

    By dividing the participants into groups based on age and menopausal status, and dividing the post-menopausal group into “takes HRT” and “no HRT” groups, and dividing the pre-menopausal group into “normal ovarian function” and “ovarian production of estrogen suppressed to mimic slightly early menopause” groups (there’s a drug for that), and then having groups exposed to warm and cold temperatures, and measuring BAT metabolism in all cases, they were able to find…

    It is about estrogen, not age!

    You can read more about the study here:

    “Good” fat metabolism changes tied to estrogen loss, not necessarily to aging, shows study

    …and the study itself, here:

    Brown adipose tissue metabolism in women is dependent on ovarian status

    What does this mean for men?

    This means nothing directly for (cis) men, sorry.

    But to satisfy your likely curiosity: yes, testosterone does at least moderately suppress BAT metabolism—based on rodent studies, anyway, because again it’s difficult to find enough human volunteers willing to have their testicles removed for science (without there being other confounding variables in play, anyway):

    Testosterone reduces metabolic brown fat activity in male mice

    So, that’s bad per se, but there isn’t much to be done about it, since the rest of your (addressing our male readers here) metabolism runs on testosterone, as do many of your bodily functions, and you would suffer many unwanted effects without it.

    However, as men do typically have notably less body fat in general than women (this is regulated by hormones), the effects of changes in BAT metabolism are rather less pronounced in men (per testosterone level changes) than in women (per estrogen level changes), because there’s less overall fat to convert.

    In summary…

    While menopausal HRT is not necessarily a silver bullet to all metabolic problems, its BAT-maintaining ability is certainly one more thing in its favor.

    See also:

    Dr. Jen Gunter | What You Should Have Been Told About The Menopause Beforehand

    Take care!

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    It’s Q&A Day at 10almonds!

    Have a question or a request? You can always hit “reply” to any of our emails, or use the feedback widget at the bottom!

    In cases where we’ve already covered something, we might link to what we wrote before, but will always be happy to revisit any of our topics again in the future too—there’s always more to say!

    As ever: if the question/request can be answered briefly, we’ll do it here in our Q&A Thursday edition. If not, we’ll make a main feature of it shortly afterwards!

    So, no question/request too big or small

    ❝I would like to see some articles on osteoporosis❞

    You might enjoy this mythbusting main feature we did a few weeks ago!

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  • Without Medicare Part B’s Shield, Patient’s Family Owes $81,000 for a Single Air-Ambulance Flight

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    Without Medicare Part B’s Shield, Patient’s Family Owes $81,000 for a Single Air-Ambulance Flight

    Debra Prichard was a retired factory worker who was careful with her money, including what she spent on medical care, said her daughter, Alicia Wieberg. “She was the kind of person who didn’t go to the doctor for anything.”

    That ended last year, when the rural Tennessee resident suffered a devastating stroke and several aneurysms. She twice was rushed from her local hospital to Vanderbilt University Medical Center in Nashville, 79 miles away, where she was treated by brain specialists. She died Oct. 31 at age 70.

    One of Prichard’s trips to the Nashville hospital was via helicopter ambulance. Wieberg said she had heard such flights could be pricey, but she didn’t realize how extraordinary the charge would be — or how her mother’s skimping on Medicare coverage could leave the family on the hook.

    Then the bill came.

    The Patient: Debra Prichard, who had Medicare Part A insurance before she died.

    Medical Service: An air-ambulance flight to Vanderbilt University Medical Center.

    Service Provider: Med-Trans Corp., a medical transportation service that is part of Global Medical Response, an industry giant backed by private equity investors. The larger company operates in all 50 states and says it has a total of 498 helicopters and airplanes.

    Total Bill: $81,739.40, none of which was covered by insurance.

    What Gives: Sky-high bills from air-ambulance providers have sparked complaints and federal action in recent years.

    For patients with private insurance coverage, the No Surprises Act, which went into effect in 2022, bars air-ambulance companies from billing people more than they would pay if the service were considered “in-network” with their health insurers. For patients with public coverage, such as Medicare or Medicaid, the government sets payment rates at much lower levels than the companies charge.

    But Prichard had opted out of the portion of Medicare that covers ambulance services.

    That meant when the bill arrived less than two weeks after her death, her estate was expected to pay the full air-ambulance fee of nearly $82,000. The main assets are 12 acres of land and her home in Decherd, Tennessee, where she lived for 48 years and raised two children. The bill for a single helicopter ride could eat up roughly a third of the estate’s value, said Wieberg, who is executor.

    The family’s predicament stems from the complicated nature of Medicare coverage.

    Prichard was enrolled only in Medicare Part A, which is free to most Americans 65 or older. That section of the federal insurance program covers inpatient care, and it paid most of her hospital bills, her daughter said.

    But Prichard declined other Medicare coverage, including Part B, which handles such things as doctor visits, outpatient treatment, and ambulance rides. Her daughter suspects she skipped that coverage to avoid the premiums most recipients pay, which currently are about $175 a month.

    Loren Adler, a health economist for the Brookings Institution who studies ambulance bills, estimated the maximum charge that Medicare would have allowed for Prichard’s flight would have been less than $10,000 if she’d signed up for Part B. The patient’s share of that would have been less than $2,000. Her estate might have owed nothing if she’d also purchased supplemental “Medigap” coverage, as many Medicare members do to cover things like coinsurance, he said.

    Nicole Michel, a spokesperson for Global Medical Response, the ambulance provider, agreed with Adler’s estimate that Medicare would have limited the charge for the flight to less than $10,000. But she said the federal program’s payment rates don’t cover the cost of providing air-ambulance services.

    “Our patient advocacy team is actively engaged with Ms. Wieberg’s attorney to determine if there was any other applicable medical coverage on the date of service that we could bill to,” Michel wrote in an email to KFF Health News. “If not, we are fully committed to working with Ms. Wieberg, as we do with all our patients, to find an equitable solution.”

    The Resolution: In mid-February, Wieberg said the company had not offered to reduce the bill.

    Wieberg said she and the attorney handling her mother’s estate both contacted the company, seeking a reduction in the bill. She said she also contacted Medicare officials, filled out a form on the No Surprises Act website, and filed a complaint with Tennessee regulators who oversee ambulance services. She said she was notified Feb. 12 that the company filed a legal claim against the estate for the entire amount.

    Wieberg said other health care providers, including ground ambulance services and the Vanderbilt hospital, wound up waiving several thousand dollars in unpaid fees for services they provided to Prichard that are normally covered by Medicare Part B.

    But as it stands, Prichard’s estate owes about $81,740 to the air-ambulance company.

    More from Bill of the Month

    The Takeaway: People who are eligible for Medicare are encouraged to sign up for Part B, unless they have private health insurance through an employer or spouse.

    “If someone with Medicare finds that they are having difficulty paying the Medicare Part B premiums, there are resources available to help compare Medicare coverage choices and learn about options to help pay for Medicare costs,” Meena Seshamani, director of the federal Center for Medicare, said in an email to KFF Health News.

    She noted that every state offers free counseling to help people navigate Medicare.

    In Tennessee, that counseling is offered by the State Health Insurance Assistance Program. Its director, Lori Galbreath, told KFF Health News she wishes more seniors would discuss their health coverage options with trained counselors like hers.

    “Every Medicare recipient’s experience is different,” she said. “We can look at their different situations and give them an unbiased view of what their next best steps could be.”

    Counselors advise that many people with modest incomes enroll in a Medicare Savings Program, which can cover their Part B premiums. In 2023, Tennessee residents could qualify for such assistance if they made less than $1,660 monthly as a single person or $2,239 as a married couple. Many people also could obtain help with other out-of-pocket expenses, such as copays for medical services.

    Wieberg, who lives in Missouri, has been preparing the family home for sale.

    She said the struggle over her mother’s air-ambulance bill makes her wonder why Medicare is split into pieces, with free coverage for inpatient care under Part A, but premiums for coverage of other crucial services under Part B.

    “Anybody past the age of 70 is likely going to need both,” she said. “And so why make it a decision of what you can afford or not afford, or what you think you’re going to use or not use?”

    Bill of the Month is a crowdsourced investigation by KFF Health News and NPR that dissects and explains medical bills. Do you have an interesting medical bill you want to share with us? Tell us about it!

    KFF Health News is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF—an independent source of health policy research, polling, and journalism. Learn more about KFF.

    Subscribe to KFF Health News’ free Morning Briefing.

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  • The Circadian Rhythm: Far More Than Most People Know

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    The Circadian Rhythm: Far More Than Most People Know

    This is Dr. Satchidananda (Satchin) Panda, the scientist behind the discovery of the blue-light sensing cell type in the retina, and the many things it affects. But, he’s discovered more…

    First, what you probably know (with a little more science)

    Dr. Panda discovered that melanopsin, a photopigment, is “the primary candidate for photoreceptor-mediated entrainment”.

    To put that in lay terms, it’s the brain’s go-to for knowing approximately what time of day or night it is, according to how much light there is (or isn’t), and how long it has (or hasn’t) been there.

    But… the brain’s “go-to” isn’t the only method. By creating mice without melanopsin, he was able to find that they still keep a circadian rhythm, even in complete darkness:

    Melanopsin (Opn4) Requirement for Normal Light-Induced Circadian Phase Shifting

    In other words, it was a helpful, but not completely necessary, means of keeping a circadian rhythm.

    So… What else is going on?

    Dr. Panda and his team did a lot of science that is well beyond the scope of this main feature, but to give you an idea:

    • With jargon: it explored the mechanisms and transcription translation negative feedback loops that regulate chronobiological processes, such as a histone lysine demathlyase 1a (JARID1a) that enhances Clock-Bmal1 transcription, and then used assorted genomic techniques to develop a model for how JARID1a works to moderate the level of Per transcription by regulating the transition between its repression and activation, and discovered that this heavily centered on hepatic gluconeogenesis and glucose homeostasis, facilitated by the protein cryptochrome regulating the fasting signal that occurs when glucagon binds to a G-protein coupled receptor, triggering CREB activation.
    • Without jargon: a special protein tells our body how to respond to eating/fasting at different times of day—and conversely, certain physiological responses triggered by eating/fasting help us know what time of day it is.
    • Simplest: our body keeps on its best cycle if we eat at the same time every day

    This is important, because our circadian rhythm matters for a lot more than sleeping/waking! Take hormones, for example:

    • Obvious hormones: testosterone and estrogen peak in the mornings around 9am, progesterone peaks between 10pm and 2am
    • Forgotten hormones: cortisol peaks in the morning around 8:30am, melatonin peaks between 10pm and 2am
    • More hormones: ghrelin (hunger hormone) peaks around 10am, leptin (satiety hormone) peaks 20 minutes after eating a certain amount of satiety-triggering food (protein does this most quickly), insulin is heavily tied to carbohydrate intake, but will still peak and trough according to when the body expects food.

    What does this mean for us in practical terms?

    For a start, it means that intermittent fasting can help guard against metabolic and related diseases (including inflammation, and thus also cancer, diabetes, arthritis, and more) a lot more if we practice it with our circadian rhythm in mind.

    So that “8-hour window” for eating, that many intermittent fasting practitioners adhere to, is going to do much, much better if it’s 10am to 6pm, rather than, say, 4pm to midnight.

    Additionally, Dr. Panda and his team found that a 12-hour eating window wasn’t sufficient to help significantly.

    Time-Restricted Feeding Is a Preventative and Therapeutic Intervention against Diverse Nutritional Challenges

    Some other take-aways:

    • For reasons beyond the scope of this article, it’s good to exercise a) early b) before eating, so getting in some exercise between 8.30am and 10am is ideal
    • It also means it’s beneficial to “front-load” eating, so a large breakfast at 10am, and smaller meals/snacks afterwards, is best.
    • It also means that getting sunlight (even if cloud-covered) around 8.30am helps guard against metabolic disorders a lot, since the light remains the body’s go-to way of knowing the time.
      • We realize that sunlight is not available at 8.30am at all latitudes at all times of year. Artificial is next-best.
    • It also means sexual desire will typically peak in men in the mornings (per testosterone) and women in the evenings (per progesterone), but this is just an interesting bit of trivia, and not so relevant to metabolic health

    What to do next…

    Want to stabilize your own circadian rhythm in the best way, and also help Dr. Panda with his research?

    His team’s (free!) app, “My Circadian Clock”, can help you track and organize all of the body’s measurable-by-you circadian events, and, if you give permission, will contribute to what will be the largest-yet human study into the topics covered today, to refine the conclusions and learn more about what works best.

    Check out the iOS app here | Check out the Android app here

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