Covid patients not infectious after 11 days, says new study

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.

Scientists have designed a “catch and kill” air filter which they say can trap the novel coronavirus and neutralise it instantly, an invention that may reduce the spread of COVID-19 in closed spaces such as schools, hospitals and health care facilities, as well as public transit environments like airplanes.

According to the study, published in the journal Materials Today Physics, the device killed 99.8 per cent of the novel coronavirus, SARS-CoV-2, in a single pass through its filter. It said the device, made from commercially available nickel foam heated to 200 degrees Celsius, also killed 99.9 per cent of the spores of the deadly bacterium Bacillus anthracis which causes the anthrax disease.

“This filter could be useful in airports and in airplanes, in office buildings, schools, and cruise ships to stop the spread of COVID-19,” said Zhifeng Ren, a co-author of the study from the University of Houston (UH) in the US.

“Its ability to help control the spread of the virus could be very useful for society,” Ren added.

The researchers said they are also developing a desk-top model for the device which is capable of purifying the air in an office worker’s immediate surroundings. According to the scientists, since the virus can remain in the air for about three hours, a filter that could remove it quickly was a viable plan, and with businesses reopening across the world, they believe controlling the spread in air conditioned spaces was urgent.

The study noted that the novel coronavirus cannot survive temperatures above 70 degrees Celsius, so by making the filter temperature far hotter — about 200 degree Celsius, the researchers said they were able to kill the virus almost instantly.

Ren said the nickel foam met several key requirements. “It is porous, allowing the flow of air, and electrically conductive, which allowed it to be heated. It is also flexible,” the researchers noted in a statement.But they added that nickel foam also had low resistivity, making it difficult to raise the temperature high enough to quickly kill the virus.

The researchers said they solved this problem by folding the foam, connecting multiple compartments with electrical wires to increase the resistance high enough to raise the temperature as high as 250 degrees Celsius. By making the filter electrically heated, rather than heating it from an external source, they said the the amount of heat that escaped from the filter is minimised, allowing air conditioning to function with very low strain.

When the scientists built and tested a prototype for the relationship between voltage/current and temperature, they said it satisfies the requirements for conventional heating, ventilation, and air conditioning (HVAC) systems, and could kill the coronavirus.

“This novel biodefense indoor air protection technology offers the first-in-line prevention against environmentally mediated transmission of airborne SARS-CoV-2, and will be on the forefront of technologies available to combat the current pandemic and any future airborne biothreats in indoor environments,” said Faisal Cheema, another co-author of the study from UH.

The researchers have called for a phased roll-out of the device, “beginning with high-priority venues, where essential workers are at elevated risk of exposure.” They believe the novel device will both improve safety for frontline workers in essential industries and allow nonessential workers to return to public work spaces.

Food with high water content is highly prescribed by doctors to stay hydrated during the summers, a season that summons a wave of soaring temperatures, higher than 40-degrees.

A much-loved fruit in India, apples are hydrating heros' in such a situation. A heatwave can affect human health in a varied manner and to maintain ideal body temperature in this soaring summer, one must remain adequately hydrated, be protected from the sun and maintain hygiene.

Working professionals and people who must step out in summers, are prone to the heatwave impact. Pediatric experts and doctors agree on the benefits of drinking water and eating fruits, especially, apples. 'An apple a day, keeps the doctor away' is true as they are rich in a number of vitamins with great anti-inflammatory benefits and many other essential minerals. Washington Apple Commission spells how apples can prove to be a summer-friendly fruit.

People often don't realise the danger of exposing themselves to extreme heat. Older adults, young children, and people with chronic illnesses are most at greater risk for serious problems. The nutrition benefits of apples may help not only in avoiding such illnesses but may also protect against many such conditions.

As popular as apples are as a fruit, they are enriched in antioxidants, dietary fibers, vitamins and a range of other nutrients that are greatly beneficial in maintaining good health. The fruit is rich in soluble fibers which may help prevent several health conditions and may lower the risk of major diseases such as heat strokes, diabetes and cancer.

The soluble fiber also promotes weight loss and improves gut health. The prebiotic effects of apples help feed the good bacteria in the gut, thus, improving digestion.

Apples are made of 85 percent water and contain vitamins, fibres and antioxidants. A high fibre content is a particularly beneficial property of apples, as improper digestion is a major health concern in the tropical climatic region. Apples are also enriched in antioxidants that help protect the lungs from oxidative damage and help oxygen flow through the blood.

Apple-based recipes

Make interesting snacks, dessert, beverages and savoury meals with this miraculous fruit during summers.

Salted apple caramel galette

Caramel apples get a grown-up makeover with this Salted Caramel Apple Galette. Warm, gooey, and delicious, this pastry is loaded with apples and homemade caramel. It's a sophisticated take on a childhood favorite and since it's easier to make than pie, it's perfect for summer get-togethers.

Caramel apple pie ice-cream sandwiches

Nothing is better at a cookout on a warm day than a cold, refreshing ice cream sandwich. In Caramel Apple Pie Ice Cream Sandwiches, the comforting flavor of apple pie is recreated in a creamy frozen banana-based ice cream studded with apple and date pieces. Then that scoop of ice cream is sandwiched between two pieces of no-bake cinnamon oat cookie dough.