Blue corn may help fight heart disease, diabetes, BP and cancer: Scientists

COVID-19 mostly kills through an overreaction of the immune system, whose function is precisely to fight infections, say scientists who have decoded the mechanisms, symptoms, and diagnosis of the disease caused by the SARS-Cov-2 coronavirus.

In a study published in the journal Frontiers in Public Health, the researchers explained step-by-step how the virus infects the airways, multiplies inside cells, and in severe cases causes the immune defences to overshoot with a "cytokine storm".

This storm is an over-activation of white blood cells, which release too-great amounts of cytokines -- inflammation-stimulating molecules --into the blood, they said.

"Similar to what happens after infection with SARS and MERS, data show that patients with severe COVID-19 may have a cytokine storm syndrome," said study author Daishun Liu, Professor at Zunyi Medical University in China.

"The rapidly increased cytokines attract an excess of immune cells such as lymphocytes and neutrophils, resulting in an infiltration of these cells into lung tissue and thus cause lung injury," Liu said.

The researchers explained that the cytokine storm ultimately causes high fever, excessive leakiness of blood vessels, and blood clotting inside the body.

It also causes extremely low blood pressure, lack of oxygen and excess acidity of the blood, and build-up of fluids in the lungs, they said.

The researchers noted that white blood cells are misdirected to attack and inflame even healthy tissue, leading to failure of the lungs, heart, liver, intestines, kidneys, and genitals.

This multiple organ dysfunction syndrome (MODS) may worsen and shutdown the lungs, a condition called acute respiratory distress syndrome, (ARDS), they said.

This, the researchers explained, happens due to the formation of a so-called hyaline membrane -- composed of debris of proteins and dead cells -- lining the lungs, which makes absorption of oxygen difficult.

Most deaths due to COVID-19 are therefore due to respiratory failure, they said.

The researchers explained that in the absence of a specific antiviral cure for COVID-19, the goal of treatment must be to the fight the symptoms, and lowering the mortality rate through intensive maintenance of organ function.

For example, an artificial liver blood purification system or renal replacement therapy can be used to filter the blood through mechanical means, they said.

The team noted that especially important are methods to supplement or replace lung function, for example with non-invasive mechanical ventilation through a mask, ventilation through a tube into the windpipe, the administration of heated and humidified oxygen via a tube in the nose, or a heart-lung bypass.

The researchers stressed the importance of preventing secondary infections.

They noted that SARS-Cov-2 also invades the intestines, where it causes inflammation and leakiness of the gut lining, allowing the opportunistic entry of other disease-causing microorganisms.

The researchers advocate that this should be prevented with nutritional support, for example with probiotics -- beneficial bacteria that protect against the establishment of harmful ones -- and nutrients and amino acids to improve the immune defences and function of the intestine.

"Because treatment for now relies on aggressive treatment of symptoms, preventative protection against secondary infections, such as bacteria and fungi, is particularly important to support organ function, especially in the heart, kidneys, and liver, to try and avoid further deterioration of their condition," Liu added.

Geneva, May 17: Spraying disinfectant on the streets, as practised in some countries, does not eliminate the new coronavirus and even poses a health risk, the World Health Organization (WHO) warned on Saturday.

In a document on cleaning and disinfecting surfaces as part of the response to the virus, the WHO says spraying can be ineffective. "Spraying or fumigation of outdoor spaces, such as streets or marketplaces, is... not recommended to kill the Covid-19 virus or other pathogens because disinfectant is inactivated by dirt and debris," explains the WHO.

"Even in the absence of organic matter, chemical spraying is unlikely to adequately cover all surfaces for the duration of the required contact time needed to inactivate pathogens." The WHO said that streets and pavements are not considered as "reservoirs of infection" of Covid-19, adding that spraying disinfectants, even outside, can be "dangerous for human health".

The document also stresses that spraying individuals with disinfectants is "not recommended under any circumstances".

"This could be physically and psychologically harmful and would not reduce an infected person's ability to spread the virus through droplets or contact," said the document.

Spraying chlorine or other toxic chemicals on people can cause eye and skin irritation, bronchospasm and gastrointestinal effects, it adds.

The organisation is also warning against the systematic spraying and fumigating of disinfectants on to surfaces in indoor spaces, citing a study that has shown it to be ineffective outside direct spraying areas.

"If disinfectants are to be applied, this should be done with a cloth or wipe that has been soaked in disinfectant," it says.

The SARS-CoV-2 virus, the cause of the pandemic that has killed more than 300,000 people worldwide since its appearance in late December in China, can attach itself to surfaces and objects.

However, no precise information is currently available for the period during which the viruses remain infectious on the various surfaces.

Studies have shown that the virus can stay on several types of surfaces for several days. However, these maximum durations are only theoretical because they are recorded under laboratory conditions and should be "interpreted with caution" in the real-world environment.

Washington, Jun 20: Pregnant and postpartum women are usually at a high risk of depression and anxiety - one in seven women struggle with symptoms in the perinatal period and the coronavirus pandemic is exacerbating those struggles according to a recent study.

The study was published in Frontiers in Global Women's Health, which found that the likelihood of maternal depression and anxiety has substantially increased during the health crisis.

"The social and physical isolation measures that are critically needed to reduce the spread of the virus are taking a toll on the physical and mental health of many of us," said Dr. Margie Davenport of the University of Alberta, Canada, who co-authored the study.

For new moms, those stresses come with side effects.

"We know that experiencing depression and anxiety during pregnancy and the postpartum period can have detrimental effects on the mental and physical health of both mother and baby that can persist for years," said Davenport.

Such effects can include premature delivery, reduced mother-infant bonding, and developmental delays in infants.

The study surveyed 900 women - 520 of whom were pregnant and 380 of whom had given birth in the past year - and asked about their depression and anxiety symptoms before and during the pandemic.

Before the pandemic began, 29 percent of those women experienced moderate to high anxiety symptoms, and 15 percent experienced depressive symptoms. During the pandemic, those numbers increased - 72 percent experienced anxiety and 41percent experienced depression.

Because lockdown measures have affected daily routines and access to gyms, researchers also asked women whether their exercise habits had changed. Of the women surveyed, 64 percent reduced their physical activity since the pandemic began, while 15 percent increased and 21 percent experienced no change.

Exercise is a known way to ease depression symptoms, so limited physical activity may result in an uptick in depressive symptoms. Indeed, the study found that women who engaged in at least 150 minutes of moderate physical activity a week had significantly lower symptoms of depression and anxiety.

The findings are somewhat limited given the fact that researchers could not survey women before the pandemic began (since they could not know a pandemic would occur). The women surveyed could only offer their pre-pandemic symptoms in hindsight.

Also, while the researchers asked women about their symptoms using validated measures, only mental health care professionals can validly diagnose an individual with depression or anxiety.

The study was specifically interested in the impact of COVID-19 on new moms, but Davenport says maternal mental health is a critical issue no matter the time.

"Even when we are not in a global pandemic, many pregnant and postpartum women frequently feel isolated whether due to being hospitalized, not having family or friends around or other reasons," she said.

"It is critical to increase awareness of the impact of social (and physical) isolation on the mental health of pregnant and postpartum women," Davenport added.

Increased awareness makes diagnosis and treatment - the ultimate goal - more likely.