Covid-19, what the scientists say about it?



Mansura Chameliy, Staff Correspondent, Barta24.com
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Coronaviruses have been causing problems for humanity for a long time. Several versions are known to trigger common colds and more recently two types have set off outbreaks of deadly illnesses: severe acute respiratory syndrome (Sars) and Middle East respiratory syndrome (Mers).

But their impact has been mild compared with the global havoc unleashed by the coronavirus that is causing the Covid-19 pandemic. In only a few months it has triggered lockdowns in dozens of nations and claimed more than 1 lakh lives. And the disease continues to spread.

That is an extraordinary achievement for a spiky ball of genetic material coated in fatty chemicals called lipids, and which measures 80 billionths of a metre in diameter. Humanity has been brought low by a very humble assailant.

On the other hand, our knowledge about the Sars-CoV-2, the virus that causes Covid-19, is also remarkable. This was an organism unknown to science five months ago. Today it is the subject of study on an unprecedented scale. Vaccine projects proliferate, antiviral drug trials have been launched and new diagnostic tests are appearing.

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The questions are therefore straightforward: what have we learned over the past five months and how might that knowledge put an end to this pandemic?

The Sars-CoV-2 virus almost certainly originated in bats which have evolved fierce immune responses to viruses, researchers have discovered. These defences drive viruses to replicate faster so that they can get past bats’ immune defences. In turn, that transforms the bat into a reservoir of rapidly reproducing and highly transmissible viruses. Then when these bat viruses move into other mammals, creatures that lack a fast-response immune system, the viruses quickly spread into their new hosts. Most evidence suggests that Sars-CoV-2 started infecting humans via an intermediary species, such as pangolins.

“This virus probably jumped from a bat into another animal, and that other animal was probably near a human, maybe in a market,” says virologist Professor Edward Holmes of Sydney University. “And so if that wildlife animal has a virus it’s picked up from a bat and we’re interacting with it, there’s a good chance that the virus will then spread to the person handling the animal. Then that person will go home and spread it to someone else and we have an outbreak.”

As to the transmission of Sars-CoV-2, that occurs when droplets of water containing the virus are expelled by an infected person in a cough or sneeze.

 The way it infects people:

Virus-ridden particles are inhaled by others and come into contact with cells lining the throat and larynx. These cells have large numbers of receptors – known as Ace-2 receptors – on their surfaces. (Cell receptors play a key role in passing chemicals into cells and in triggering signals between cells.) “This virus has a surface protein that is primed to lock on that receptor and slip its RNA into the cell,” says virologist Professor Jonathan Ball of Nottingham University.

Once inside, that RNA inserts itself into the cell’s own replication machinery and makes multiple copies of the virus. These burst out of the cell, and the infection spreads. Antibodies generated by the body’s immune system eventually target the virus and in most cases halt its progress.

“A Covid-19 infection is generally mild, and that really is the secret of the virus’s success,” adds Ball. “Many people don’t even notice they have got an infection and so go around their work, homes and supermarkets infecting others.”

By contrast, Sars – which is also caused by a coronavirus – makes patients much sicker and kills about one in 10 of those infected. In most cases, these patients are hospitalized and that stops them infecting others – by cutting the transmission chain. Milder Covid-19 avoids that issue.

Occasionally, however, the virus can cause severe problems. This happens when it moves down the respiratory tract and infects the lungs, which are even richer in cells with Ace-2 receptors. Many of these cells are destroyed, and lungs become congested with bits of broken cell. In these cases, patients will require treatment in intensive care.

Even worse, in some cases, a person’s immune system goes into overdrive, attracting cells to the lungs in order to attack the virus, resulting in inflammation. This process can run out of control, more immune cells pour in, and the inflammation gets worse. This is known as a cytokine storm (In Greek, “cyto” means cell and “kino” means movement.) In some cases, this can kill the patient.

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Just why cytokine storms occur in some patients but not in the vast majority is unclear. One possibility is that some people have versions of Ace-2 receptors that are slightly more vulnerable to attacks from the coronavirus than are those of most people.

Doctors examining patients recovering from a Covid-19 infection are finding fairly high levels of neutralising antibodies in their blood. These antibodies are made by the immune system, and they coat an invading virus at specific points, blocking its ability to break into cells.

“It is clear that immune responses are being mounted against Covid-19 in infected people,” says virologist Mike Skinner of Imperial College London. “And the antibodies created by that response will provide protection against future infections – but we should note that it is unlikely this protection will be for life.”

Instead, most virologists believe that immunity against Covid-19 will last only a year or two. “That is in line with other coronaviruses that infect humans,” says Skinner. “That means that even if most people do eventually become exposed to the virus, it is still likely to become endemic – which means we would see seasonal peaks of infection of this disease. We will have reached a steady state with regard to Covid-19.”

The virus will be with us for some time, in short. But could it change its virulence? Some researchers have suggested that it could become less deadly. Others have argued that it could mutate to become more lethal. Skinner is doubtful. “We have got to consider this pandemic from the virus’s position,” he says. “It is spreading round the world very nicely. It is doing OK. Change brings it no benefit.”

In the end, it will be the development and roll-out of an effective vaccine that will free us from the threat of Covid-19, Skinner says.

On Friday April 10), the Journal Nature reported that 78 vaccine projects had been launched round the globe – with a further 37 in development. Among the projects that are under way is a vaccine program that is now in phase-one trials at Oxford University, two others at US biotechnology corporations and three more at Chinese scientific groups. Many other vaccine developers say they plan to start human testing this year.

This remarkable response raises hopes that a Covid -19 vaccine could be developed in a fairly short time. However, vaccines require large-scale safety and efficacy studies. Thousands of people would receive either the vaccine itself or a placebo to determine if the former were effective at preventing infection from the virus which they would have encountered naturally. That, inevitably, is a lengthy process.

As a result, some scientists have proposed a way to speed up the process – by deliberately exposing volunteers to the virus to determine a vaccine’s efficacy. “This approach is not without risks but has the potential to expedite candidate vaccine testing by many months,” says Nir Eyal, a professor of bioethics at Rutgers University.

It is expected that the Covid -19 antidote vaccine would soon be available. However, there must be more researches about the efficacy and safety of the vaccine. As thousands people will be given so it should be naturally safe and effective and can combat the spread of infection, it must be ensured.

Source: The Guardian

   

76 more killed in Gaza, death toll rises to nearly 32,500



International Desk, Barta24.com, Dhaka
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Even after the UN Security Council passed a cease-fire resolution, the Israeli barbaric attacks on the Palestinian-besieged Gaza have not stopped. Another 76 Palestinians were killed in Gaza in the last 24 hours by Israeli attacks. The death toll has increased to about 32,500 people. The number of injured has reached about 75000 people.

Al-Jazeera reported this information in a live update on Thursday (March 28).

Quoting the Ministry of Health of Gaza, the report said that since last October, the number of dead in Palestine has reached 32490 in the Israeli barbaric attack in the Gaza Strip.

Meanwhile, an emergency ceasefire resolution was passed in the besieged Gaza Strip. The resolution passed by the UN Security Council on Monday (March 25) calls for a cease-fire in Gaza as well as the immediate and unconditional release of hostages held by Hamas.

In this proposal, 14 countries of the Security Council voted in favor of the proposal. Israel's close ally, the United States, abstained from voting.

Welcoming the proposal, UN Secretary General Antonio Guterres said, after a long wait, the Security Council has passed a resolution regarding the cease-fire in Gaza. This proposal must be implemented. Failure of any party to implement the ceasefire and its terms would constitute an unforgivable offence. 

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Israel wants to wipe out Palestinians: UN



International Desk, Barta24.com, Dhaka
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Gazans are going through one of the worst times in living memory. The lives of Palestinians are in danger due to the long-term killings and severe food shortages. The world is criticizing the surprise attack on the destitute Gazans. However, Israeli President Benjamin Netanyahu is unwilling to stop the attack. In this situation, the international organization, which could not find any solution after repeated efforts, said that Israel is going to wipe out the Palestinians.

On Monday (March 25), the special envoy for human rights in Palestine, Francesca Albanez, released her detailed report. She said that since the start of the attack, Israel has targeted Gazans. The Israeli forces assumed that these Gazans could be attacked, killed, or even destroyed. Israel's genocidal action has become clear through this. They are trying to erase Palestinians from Palestine.

The news agency AFP reported this information.

According to the report, Albanez attacked Israel in harsh language at the meeting of the United Nations Human Rights Council. She said Israel destroyed Gaza. She also said, 'What is happening in Gaza shows the intention of genocide. We cannot turn away from it. We have to face it, we have to stop this genocide and action must be taken against those who took this step.''

Francesca Albanez is working as Special Envoy for Palestinian Human Rights. She told the United Nations Human Rights Council last Monday that the organization's member states should end arms embargoes against Israel and arms supplies to Israel.

Support for the UN expert panel, which has been working on allegations of genocide against Israel since the start of Israel's assault on Gaza, has been growing in Palestine. Various countries are now showing interest in investigating the allegations of genocide.

Ambassadors of different countries are supporting this report of Albanez. Ambassadors from Muslim and Arab countries, as well as Latin American countries, are among those supporting Albanez's report to hold Israel accountable.

Pakistan has supported this Albanez report on behalf of the Organization of Islamic Cooperation (OIC). The OIC has also called for an arms embargo on Israel. When Albanez presented the report to the United Nations Human Rights Council, Pakistan's representative said, "We appreciate your courage in documenting the genocide in Gaza."

Accusations of genocide against Israel are intensifying as it continues to operate in Gaza's Rafah area in defiance of international calls. The Ministry of Health of Palestine said on Wednesday that 76 people were killed in the attack in the last 24 hours. With this, 32490 people have been killed in Israel's attacks since October 7.

The representative of Egypt, on behalf of the Arab countries, said they were deeply concerned about Israel's structural and systematic attack on the Gaza Strip, making it uninhabitable. Qatar represented the Gulf countries in the meeting. They want international action to stop the war that Israel is waging in Palestine. 

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Romania sent back 5 Bangladeshis with ban



International Desk, Barta24.com, Dhaka
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Immigration police in the Arad region bordering Romania forcibly returned 20 migrants to their respective countries on charges of attempting to cross the border illegally. Five Bangladeshis are among the migrants.

Romania's General Inspectorate for Immigration (IGI) announced this information in a press release on Monday (March 25).

According to the notification, on March 23, the Immigration police of Arad region of Romania forcibly sent back to their respective countries a total of 20 immigrants, including 18 people from South Asian countries and 2 people from Egypt. The concerned migrants were taken from the migrant detention center in Arad region to the airport in the presence of law enforcement agencies.

Apart from five Bangladeshis, the migrants include nine Sri Lankans, three Pakistanis, two Egyptians and one Indian national. A legal notice to leave Romania was issued against them earlier. But as they did not return on their own initiative, forced expulsion was implemented with an escort according to the law.

Upon leaving Romania, they are banned from entering all EU member states, the European Economic Area and the Swiss Confederation for five years.

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18 killed in Gaza after relief sack fell on head



International Desk, Barta24.com, Dhaka
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18 people were killed while collecting airdropped aid in the besieged Gaza Strip. The casualties occurred during an airdrop of relief near the Mediterranean coast in northern Gaza. At that time, 12 people were killed when relief sacks fell on their heads and 6 others died after being trampled in haste while collecting relief. AFP reports.

Hamas, the armed political group that controls the valley, said in a statement that the tragedy occurred on Tuesday (March 25).

In the statement, Hamas said, "A request to the international community, please stop dropping the relief bags from the planes." Instead, take steps to remove the obstacles in sending relief by road.'

More than 32,000 Palestinians have been killed in Gaza in the last six months of Israeli forces' operations, and about 74,000 others have been injured.

On the other hand, 1,200 Israeli soldiers were killed in an attack by Hamas fighters on October 7. Also, 240 people were taken hostage by Hamas fighters, 108 of them have been released so far.

A third of the people of the Gaza Strip are directly dependent on aid from the United Nations and other donor countries and groups. Since the beginning of the operation in the valley, the Israeli forces have been blocking the delivery of relief supplies, resulting in a death march in Gaza since last February due to lack of food.

In this situation, the United States and its allies in the Western world announced air relief supplies to the Gaza Strip from that month.

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