Antimicrobial and antibiotic drug resistance: Causes and more

Has A 'quademic' Hit The US? 4 Viral Infections And What To Know About Them

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Four viruses are circulating in the U.S., sparking concerns of a possible "quademic."

Influenza, COVID-19, RSV and norovirus are all at "very high levels" around the country, according to Samuel Scarpino, director of AI and life sciences and professor of health sciences at Northeastern University in Boston.

"We are in the middle of a very serious situation with respect to circulating pathogens," he told Fox News Digital.

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"Based on data from our national wastewater surveillance system, some parts of the country, such as Boston, seem to be entering the peak for all four diseases, but in other areas, cases are still rising," Scarpino added.

There are vaccines currently available for COVID, flu and RSV, but not for norovirus — although there is an mRNA vaccine in development, one expert pointed out. (iStock)

Dr. Marc Siegel, clinical professor of medicine at NYU Langone Health and Fox News senior medical analyst, noted that it is currently peak respiratory virus season.

"It is not a 'quad-demic,' per se, just a lot of respiratory viruses and bacteria at once," he said to Fox News Digital.

On top of the four viruses, Siegel warned of some bacterial outbreaks that can cause respiratory illness, such as mycoplasma, pertussis and strep.

Viruses by the numbers

The Centers for Disease Control and Prevention (CDC) reported an 18.8% positivity rate for flu tests for the week ending Jan. 11, stating that "seasonal influenza activity remains elevated across most of the country."

There were also 11 pediatric deaths related to influenza, bringing the total to 27 deaths this season, the agency stated.

"We are in the middle of a very serious situation with respect to circulating pathogens."

COVID-19 was at a 6.6% test positivity as of Jan. 11, with 1.3% of emergency room visits resulting in a diagnosis and 1.8% of all deaths linked to the virus, per CDC data.

RSV (respiratory syncytial virus, which is a highly contagious virus that infects the lungs, nose and throat) has a test positivity of 8.9%.

With the onset of these common seasonal viruses, one doctor said it's important for patients to have a "great relationship" with a primary care physician.  (iStock)

Cases of norovirus, more commonly known as the stomach bug, are also surging. 

Between August 1 and Dec. 11, 2024, there were 495 norovirus outbreaks reported in the U.S., compared to 363 in the same time period last year, according to the CDC.

Differentiating between viruses

Kenneth Perry, MD, an emergency physician in South Carolina, said his hospital has recently seen an uptick in emergency department visits tied to these infections.

"From cough to nasal congestion and even fever, it is difficult to differentiate between the discrete viruses," he told Fox News Digital. "For most people, knowing which virus they have is purely an academic discussion. For some patients, however, the specific virus is very important."

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The possibility of someone having all four viruses at once is very low, Perry said — "but it's not completely out of the realm of possibility for people to have two or even three at the same time."

Siegel agreed that with multiple viruses circulating, it can be a challenge for practicing internists and infectious disease specialists to tell the difference.

"It is not a 'quad-demic,' per se, just a lot of respiratory viruses and bacteria at once," Dr. Marc Siegel said to Fox News Digital. (iStock)

"Respiratory panels at hospitals, urgent care centers and labs can be helpful to distinguish between them," he said.

There are combined rapid tests available that simultaneously screen for two types of influenza and COVID, Scarpino pointed out. 

Potential risk factors

"Of the four viruses in widespread circulation, all post a unique risk of severe illness in the elderly," Dr. Jacob Glanville, CEO of Centivax, a San Francisco biotechnology company, told Fox News Digital.

RSV poses unique risks for infants, experts agree.

"Of the four viruses in widespread circulation, all post a unique risk of severe illness in the elderly."

"For young infants, breathing through their nose is imperative in order to eat, and RSV can cause severe amounts of nasal congestion," Perry warned. This congestion can disrupt babies' ability to consume enough calories, he added.

For norovirus, dehydration can become a "major problem," according to Perry. 

"Again, young infants who cannot have water or sports drinks to help maintain hydration can be most susceptible."

There are combined rapid tests available that simultaneously screen for two types of influenza and COVID. (iStock)

Long COVID is a "significant concern" for most adults, according to Glanville, "as the chronic disorder is yet to be fully understood and effective treatments have yet to be developed."

Scarpino noted that influenza has historically been a leading cause of death in the U.S.

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"Despite us being more used to worrying about COVID these days, it's important to take the flu very seriously," he added.

People with underlying risk factors are at a higher risk of severe illness for all four viruses, Scarpino added.

Prevention and treatment

To prevent these four circulating viruses, Glanville recommends getting vaccinated when available, avoiding contact with those who are infected, and following proper sanitation practices.

"The best thing you can do to keep from getting any of these viruses is to keep your hands clean," Perry advised. "Washing hands especially after touching public surfaces is going to be the best way to keep from getting any of these viruses."

"The best thing you can do to keep from getting any of these viruses is to keep your hands clean," an emergency room physician advised. (iStock)

There are vaccines currently available for COVID, flu and RSV, but not for norovirus — although there is an mRNA vaccine in development, Scarpino pointed out.

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"Even in places where cases have started falling, we're far from being out of the woods, so there's still time to get vaccinated," he said.

For those who contract any of the viruses, Siegel recommends focusing on hydration, getting plenty of rest and carefully monitoring symptoms.

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People who are sick should stay home, avoid interacting directly with others and wear masks in close quarters, the doctor advised.

Perry pointed out that flu and COVID are "cyclical" in their level of severity. 

"The best thing you can do to keep from getting any of these viruses is to keep your hands clean."

"There are years when the flu virus is very mild, and others when it is more virulent," he told Fox News Digital. "The same goes for COVID, as we saw with the different variants that were present throughout the pandemic."

With the onset of these common seasonal viruses, Perry said it's important for patients to have a "great relationship" with a primary care physician. 

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"This way, their risk category is well-known to their doctor and they can easily get the correct care for their health, even if they get one of these viruses."

7 Different Types Of Pneumonia

There are more than seven main types of pneumonia, including community-acquired pneumonia caused by bacteria and viruses. Other types include walking, aspiration, chemical, and hospital-acquired pneumonia. Fungal pneumonia includes more rare types of pneumonia.

Pneumonia is an infection and inflammation of your lungs that occurs if the air sacs fill with fluid or pus. It causes symptoms like chest pain, cough, and shortness of breath. Knowing what kind of pneumonia you have can help treat the illness. 

More than 900,000 people in the United States develop bacterial pneumonia yearly. Bacteria are one of the most common causes of pneumonia. Streptococcus is a type of bacterium that causes bacterial pneumonia. It typically lives in your upper respiratory tract. The bacteria can sometimes travel into your lungs and cause an infection. Bacterial pneumonia typically causes more severe illness than other types. You may develop these symptoms slowly, or they may suddenly appear: Blue lips and nails Confusion Excessive sweating Fever, which may be as high as 105 degrees Fahrenheit (40.6 degrees Celsius) Rapid breathing or heart rate Antibiotics treat bacterial pneumonia. It is essential to take antibiotics as a healthcare provider prescribes. Bacterial pneumonia symptoms improve over a few days, but a cough may linger for weeks. Viruses that cause viral pneumonia may include: Adenovirus Human parainfluenza viruses (HPIVs) Influenza viruses Measles virus Respiratory syncytial virus (RSV) SARS-CoV-2, which causes COVID-19 Early viral pneumonia symptoms resemble the flu, then gradually worsen. Older adults may have mild symptoms, including a low body temperature and confusion. Younger children may not develop symptoms or be restless or tired and vomit. People with chronic lung disease can have severe symptoms. Antibiotics do not treat viral pneumonia, but corticosteroids may help. If you have a mild illness, getting plenty of rest and staying hydrated can help. Advil (ibuprofen) and Tylenol (acetaminophen) can reduce a fever. In severe cases, you may require intravenous (IV) fluids and supplemental oxygen. The term "walking pneumonia" is not an actual medical diagnosis. It describes a case of pneumonia that's not severe enough to put you in bed. Less common bacteria typically cause walking pneumonia. Mycoplasma pneumoniae often causes infection in people younger than 40 years old. Legionella pneumophila causes illness in older adults, people who smoke, and those with a weak immune system. Pneumonia caused by this bacteria is known as Legionnaire disease. Walking pneumonia usually causes mild symptoms, such as: Ear and eye pain Lump in the neck area Rash Sore throat Legionnaire disease causes symptoms like bloody mucus and diarrhea. These symptoms typically worsen over four to six days before they improve. Walking pneumonia can be treated with antibiotics, fever reducers, fluids, and rest. In severe cases, IV antibiotics and supplemental oxygen in a hospital may be required. People contract fungal pneumonia if they breathe in certain fungal spores. Types of fungal pneumonia include: Histoplasmosis: This is caused by the fungus Histoplasma, commonly found in the Central and Eastern United States. This fungus lives in bat or bird droppings and soil. Pneumocystis pneumonia (PCP): Pneumocystis jirovecii is a fungus in your lungs. PCP happens if this fungus grows out of control, typically in people with a weak immune system. Valley fever: This is caused by the fungus Coccidioides, which lives in soil in the Southwestern United States.  PCP causes general pneumonia symptoms. Histoplasmosis typically does not cause symptoms. Valley fever may cause flu-like symptoms that go away within weeks to months. Some people may develop a severe chronic lung infection. Fungal pneumonia does not spread from person to person. Treatment usually involves antifungal medicines. Aspiration pneumonia happens when you accidentally inhale food, liquid, saliva, or vomit into your lungs. Risk factors that increase the likelihood of aspiration pneumonia include: Being hospitalized Coma General anesthesia Heavy alcohol or drug use Older age Trouble swallowing Antibiotics help treat this type of pneumonia. Some people require a ventilator to help them breathe normally. Others may need a feeding tube if they have trouble swallowing. People typically acquire chemical pneumonia from breathing in fumes from certain chemicals at home or in the workplace. Chemicals that cause pneumonia include chlorine gas, noxious fumes from pesticides, and smoke from wildfires. These chemicals can physically irritate your lungs. You may develop chronic pneumonia if you continuously breathe in chemical fumes over long periods. Chemical pneumonia may cause symptoms like: Breathing that sounds abnormal (i.E., gurgling or wet breathing) Burning feeling in your chest Feeling like you cannot breathe in enough air Trouble swallowing  Corticosteroids help reduce inflammation. A healthcare provider may provide supplemental oxygen until your lungs heal. Some people must eat small meals while sitting upright or require a feeding tube if they have trouble swallowing. Hospital-acquired pneumonia develops during hospital stays, typically in people who are on a ventilator. The tube goes through the trachea (windpipe) so you can maintain oxygen to your heart and brain. It can be a conduit for germs to enter your lungs. A healthcare provider can also spread germs from their clothes, equipment, or hands. People who use a ventilator are often already sick. Pneumonia is more likely to cause severe symptoms, such as hypotension (low blood pressure) and a rapid heart rate. If pneumonia is caused by bacteria, treatment may include IV antibiotics. Supplemental oxygen and a ventilator help support breathing. Certain types of pneumonia may have unique symptoms. No matter the cause, pneumonia generally causes symptoms like: Chest pain that worsens with deep breathing or coughing Confusion Cough, with or without blood-tinged, green, or yellow mucus Fever, with chills and sweating Lack of energy Loss of appetite Nausea Rapid breathing Shortness of breath Vomiting Anyone can contract a bacterial, fungal, or viral infection and develop pneumonia. Some risk factors increase the likelihood of pneumonia, such as: Being younger than 2 years old or older than 65 years old Alcohol use disorder Chemical, pollutant, and toxic fume exposure Lung disease Malnourishment Recent viral infections, such as a cold or the flu Smoking Staying in a hospital, especially in the intensive care unit (ICU), and being sedated or on a ventilator Trouble coughing or swallowing Weak immune system It's important to see a healthcare provider if you develop pneumonia symptoms, especially if you are part of a high-risk population. A healthcare provider can diagnose the underlying cause and recommend treatments. Get medical attention right away if you have symptoms like: A fever that goes away and then comes back Blue fingers or skin Breathing that gets too fast and shallow Confusion Coughing up blood or dark-colored mucus Frequent headaches Needing to lean forward to breathe easily Tiredness Various bacteria, fungi, or viruses may cause pneumonia. Diagnosing the type of pneumonia you have helps treat it. A healthcare provider can guide you through treatment, whether you need rest, antibiotics, or supplemental oxygen. Vaccines can prevent certain types of pneumonia. Consult a healthcare provider about what vaccines can help reduce your risk of viral infections that may lead to pneumonia, like COVID and the flu. Proper hygiene, as well as a balanced diet, regular exercise, and not smoking, can also prevent infection.

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Why Viral Infections Are More Severe In People With Down Syndrome

After his best friend from high school had a daughter with Down syndrome, immunologist Dusan Bogunovic of the Icahn School of Medicine at Mount Sinai in New York pored over decades of research to better understand the condition. As he read through the literature, he began to notice overlaps between Down syndrome and more severe genetic disorders that stem from over-producing interferons—molecules that open the innate immune system's floodgates by activating hundreds of genes that guard against viral infections and trigger inflammation to curb disease after an infection occurs.

Now, about six years later, Bogunovic and colleagues report evidence that a hypersensitivity to interferons, specifically those classified as type I, may paradoxically blunt responses to those signaling molecules after infection, causing an immunosuppressed state that can let inflammation run rampant. The findings, published today (October 14) in Immunity, may help explain why viruses tend to infect people with Down syndrome less often than people without the condition, but when they do, illness is more severe.

See "Lots of Rapid Evolution in Interferon-Stimulated Genes: Study"

"I think [this research] is a very elegant way to test how interferon receptors might trigger different feedback," says Xiao-Fei Kong, an immunology researcher and clinician at UT Southwestern Medical Center in Texas who has worked previously with Bogunovic but was not involved in this research. "This is also an important question to answer: why those patients with Down syndrome suffer from severe viral infection."

Down syndrome, also called trisomy 21, is the most common chromosomal disease in the US; around 1 out of every 700 babies are born with the condition. The study authors write that while recent research indicates people with Down syndrome are less likely than the general population to catch certain viruses (such as influenza), they are significantly more likely to be hospitalized or die from illness caused by respiratory viruses. For example, post-infection mortality due to COVID-19 is about 10 times higher in people with Down syndrome compared to those without the condition, says Bogunovic.

Because Down syndrome arises from having a third copy of chromosome 21, people with the condition have an extra copy of the more than 200 genes on that chromosome. That includes genes like IFNAR1 and IFNAR2, which code for receptors that bind to interferons.

Transcriptomic analyses confirmed the researchers' expectation that these interferon receptors are expressed at levels roughly 1.5 times higher in fibroblast cell lines derived from people with Down syndrome (DS cells) than lines derived from controls without trisomy 21, says study coauthor Lousie Malle, an immunology researcher at Icahn. However, knowing that a receptor gene is expressed more highly "doesn't necessarily tell you how the target genes of the pathway are going to be expressed," says Malle. "It's usually not linear."

To measure the downstream impact of having more receptors, the researchers exposed cells to interferons to activate the receptors, and found that the expression of infection-fighting interferon-simulated genes (ISGs) was up to six-fold higher in the DS cells than in control cells. The results suggest that "individuals with Down syndrome are hypersensitive to small amounts of interferon," Bogunovic says. "So something that me and you would barely sense—because they have more of these receptors, they're hyper-responding."

See "Study Points to Novel Role for Microglia in Down Syndrome"

After a virus infects us, Bogunovic says that our bodies harness the power of our innate immune systems, fighting the pathogen through inflammation such as with a fever. "But we need to stop [the] fever, otherwise we're going to kill ourselves," he says, so a negative feedback mechanism kicks in to subdue inflammation. Some of the ISGs responsible for fighting infection also lead to the expression of inhibitory molecules like USP18 that block interferon receptors. "These are the brakes that come on," he says, because they prevent interferon from continuing to push the immune system's gas pedal.

However, because DS cells are more stimulated by interferons initially, these brakes slam on like a car screeching to a halt, overly suppressing inflammation, Bogunovic says. This happens to such an extent that thereafter, the DS cells hardly responded to interferons, resulting in "what we call the inflammation-caused immunosuppressed state, which is a paradox," he says, because the inflammation normally relied upon to fight infection apparently dampens the innate immune response.

Thanks to elevated levels of interferon receptors, people with Down syndrome (solid line) exhibit a higher initial response to a viral pathogen than those without trisomy 21 (dashed line). However, their greater initial defense is accompanied by overzealous tamping down of the immune response, leading to susceptibility later on, Dusan Bogunovic and colleagues posit.

He and his colleagues hypothesized that individuals with Down syndrome could be more vulnerable to viral disease while this suppression occurs. To test this, the researchers first exposed control and DS cells to a dose of interferon, then exposed them to influenza A virus. This initial dose prevented some infection in both types of cells: about 48 percent of the healthy control cells were infected compared to about 43 percent of the DS cells. Then the researchers repeated the experiment, this time giving the cells an additional dose of interferons before exposing them to the virus. Only the control cells showed a reduction in infection rate (with only 33 percent of cells infected) from the second interferon jolt; the percent of infected DS cells was once again about 43 percent. To the team, this suggested that during the hyposensitive stage, viruses may be more able to spread throughout the body.

Kong isn't as certain about DS cells being more susceptible to the flu virus, saying that the in vitro data only show "very mild effects." Bugonavic agrees but says a mild response was expected considering Down syndrome patients do not often die of the flu. Testing SARS-CoV-2, because of its higher mortality rate and worse health outcomes, could show a more pronounced effect, he says.

The researchers also experimented with blood cells from humans with and without Down syndrome to get a better indication of how their findings might translate to human health. In line with previous research, blood cells from people with Down syndrome showed higher steady-state interferon levels compared to controls. In addition, immunoblotting revealed evidence of USP18—one of the molecular brakes—in the blood cells taken from people with Down syndrome, but not in the controls. Finally, exposure to interferons induced less of an innate immune response in these cells than the controls.

Taken together, the authors argue these results indicate the innate immune systems of people with Down syndrome may generally exist in a partially desensitized state. Malle says that their interferon levels may be "high enough to provide some baseline defense," but may not be enough for "the really well-orchestrated response that you need to fight off a severe infection."

"I think this [provides] new insights into understanding interferon, but there are still a lot of questions," says Kong. His interpretation is that the response of DS blood cells to subsequent interferon stimulation was "still pretty strong," and describes the USP18 expression as so low that it might not significantly inhibit interferon's ability to activate receptors. "I'm not really convinced that monocytes or myeloid cells are desensitized."

Kelly Sullivan, a molecular biologist at the Linda Crnic Institute for Down Syndrome at the University of Colorado, Anschutz Medical Campus who was not involved in the work, agrees that the data showing USP18 in the blood cells aren't the most compelling, but notes that low levels of a protein don't preclude it from having a large effect. He says that the data comparing DS and healthy blood cells do validate the authors' claim that the DS cells are partially desensitized. "I think there's still quite a lot of work to do to really unravel what [the] clinical implications could be," he says, but taken together, these data suggest that "by restoring that basal level of interferon signaling, we might be able to rescue that appropriate secondary response to the viral infection."

And that's the overall goal, says Bogunovic. In additional in vitro experiments, the team demonstrated that well-timed pulses of JAK inhibitors—immunosuppressants that he likens to artificial USP18—can help smooth out how the innate immune system's brakes are applied in DS cells and normalize the immune response after infection. "We hope that [by] understanding the dynamics of the immune system—which goes up and then goes down—that we can start manipulating [it] in a way that can benefit the health [of] individuals with Down syndrome," Bogunovic says, adding that he and his colleagues are planning future clinical trials to evaluate this possibility.

The authors write that it's likely people with Down syndrome are more susceptible to disease from viral infections because of a combination of factors: the initial hypersensitivity and subsequent hyposensitivity of their innate immune systems as indicated in these findings, previously reported deficiencies in their adaptive immune systems, and anatomical anomalies in their respiratory tracts.

"Individuals with Down syndrome have a complex immune dysregulation. And there are many aspects of disease that need untangling," says Bogunovic. "What we have discovered here is a piece of that puzzle, which we think is very important."

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