Cow may be biggest mammal if humans keep up extinctions: Study

Agencies
May 12, 2018

Oslo, May 12: The spread of humans around the world from Africa thousands of years ago wiped out big mammals in a shrinking trend that could make the cow the biggest mammal on Earth in a few centuries` time, a scientific study said on Thursday.

The spread of hominims - early humans and relatives such as Neanderthals - from Africa coincided with the extinction of mammals such as the mammoths, sabre-toothed tiger and glyptodon, an armadillo-like creature the size of a car.

"There is a very clear pattern of size-biased extinction that follows the migration of hominims out of Africa," lead author Felisa Smith of the University of New Mexico told Reuters of the study published in the journal Science.

Humans apparently targeted big species for meat, while smaller creatures such as rodents escaped, according to the report examining trends over 125,000 years.

In North America, for instance, the mean body mass of land-based mammals has shrunk to 7.6 kg (17 lbs) from 98.0 after humans arrived.

If the trend continues "the largest mammal on Earth in a few hundred years may well be a domestic cow at about 900 kg" (2,000 lbs), the U.S. team wrote.

That would mean the loss of creatures including elephants, giraffes and hippos. In March, the world`s last male northern white rhino died in Kenya.

But other research casts doubt on a continued shrinking of mammals, partly because of conservation efforts to stave off threats to wildlife such as climate change, loss of forest habitats and pollution and expanding cities.

Thomas Brooks, chief scientist of the International Union for Conservation of Nature (IUCN) who was not involved in the study, said the projection of ever smaller mammals was "doom and gloom."

"Happily I don`t think it`s very likely," he told Reuters, saying that other research suggests that large animals such as elephants are more likely to benefit in protected areas than smaller ones.

And a Red List of threatened species, maintained by the IUCN, also lists some wild mammals roughly the size of a cow - such as the African buffalo or the brown bear - as unendangered.

The Science study also excludes marine mammals such as the blue whale, the largest creature that has ever existed. It is endangered on the Red List but the populations are rising after a moratorium on hunts.

Smith said that "my optimist hat would like to say that it`s not going to happen because we love elephants`." But she said populations of large land mammals were falling and "declining population is the trajectory to extinction."

Comments

Add new comment

  • Coastaldigest.com reserves the right to delete or block any comments.
  • Coastaldigset.com is not responsible for its readers’ comments.
  • Comments that are abusive, incendiary or irrelevant are strictly prohibited.
  • Please use a genuine email ID and provide your name to avoid reject.
Agencies
March 15,2020

Jakarta, Mar 15: Indonesia's transport minister is in intensive care after testing positive for the novel coronavirus, an official has said, as schools and tourist attractions were ordered to close over the health threat.

Transportation Minister Budi Karya Sumadi was receiving treatment at an army hospital in Jakarta, State Secretary Pratikno said on Saturday.

A hospital spokesman said Sumadi was encountering difficulty breathing but that his condition was improving.

Pratikno said Sumadi was involved in virus mitigation efforts, particularly the evacuation of Indonesians from epicenters of the outbreak, and that President Joko Widodo had called for tests to be carried out on other ministers.

Cases of the virus in Indonesia, the world's fourth most populous country, have jumped from zero two weeks ago to 96, with five deaths, according to government spokesperson Achmad Yurianto.

He also said the virus has spread outside Greater Jakarta to Bandung in West Java, Solo in Central Java, Manado in North Sulawesi, Pontianak in West Kalimantan, as well as holiday havens Yogyakarta and Bali.

Following the increase, the government on Saturday established a task force on COVID-19 mitigation.

Jakarta's Governor Anies Baswedan announced that schools would close for two weeks starting Monday, and ordered the closure of city-owned tourist attractions, such as Ragunan Zoo and Ancol beach.

He emphasized that Jakarta would not be locked down but urged people "to be responsible" and called for social distancing when possible.

Similarly, the administration of Solo, Central Java, Friday announced that schools and tourist attractions would close after a coronavirus patient died in the region.

The World Health Organization has said it is particularly concerned about high-risk nations with weaker health systems, which who may lack the facilities to identify cases.

A day after declaring the coronavirus outbreak to be pandemic this week, WHO chief Tedros Adhanom Ghebreyesus called Indonesia's president Widodo and both agreed to "scale up cooperation."

Comments

Add new comment

  • Coastaldigest.com reserves the right to delete or block any comments.
  • Coastaldigset.com is not responsible for its readers’ comments.
  • Comments that are abusive, incendiary or irrelevant are strictly prohibited.
  • Please use a genuine email ID and provide your name to avoid reject.
News Network
April 17,2020

Paris, Apr 17: Even as virologists zero in on the virus that causes COVID-19, a very basic question remains unanswered: do those who recover from the disease have immunity?

There is no clear answer to this question, experts say, even if many have assumed that contracting the potentially deadly disease confers immunity, at least for a while.

"Being immunised means that you have developed an immune response against a virus such that you can repulse it," explained Eric Vivier, a professor of immunology in the public hospital system in Marseilles.

"Our immune systems remember, which normally prevents you from being infected by the same virus later on."

For some viral diseases such a measles, overcoming the sickness confers immunity for life.

But for RNA-based viruses such as Sars-Cov-2 -- the scientific name for the bug that causes the COVID-19 disease -- it takes about three weeks to build up a sufficient quantity of antibodies, and even then they may provide protection for only a few months, Vivier told AFP.

At least that is the theory. In reality, the new coronavirus has thrown up one surprise after another, to the point where virologists and epidemiologists are sure of very little.

"We do not have the answers to that -- it's an unknown," Michael Ryan, executive director of the World Health Organization's Emergencies Programme said in a press conference this week when asked how long a recovered COVID-19 patient would have immunity.

"We would expect that to be a reasonable period of protection, but it is very difficult to say with a new virus -- we can only extrapolate from other coronaviruses, and even that data is quite limited."

For SARS, which killed about 800 people across the world in 2002 and 2003, recovered patients remained protected "for about three years, on average," Francois Balloux director of the Genetics Institute at University College London, said.

"One can certainly get reinfected, but after how much time? We'll only know retroactively."

A recent study from China that has not gone through peer review reported on rhesus monkeys that recovered from Sars-Cov-2 and did not get reinfected when exposed once again to the virus.

"But that doesn't really reveal anything," said Pasteur Institute researcher Frederic Tangy, noting that the experiment unfolded over only a month.

Indeed,several cases from South Korea -- one of the first countries hit by the new coronavirus -- found that patients who recovered from COVID-19 later tested positive for the virus.

But there are several ways to explain that outcome, scientists cautioned.

While it is not impossible that these individuals became infected a second time, there is little evidence this is what happened.

More likely, said Balloux, is that the virus never completely disappeared in the first place and remains -- dormant and asymptomatic -- as a "chronic infection", like herpes.

As tests for live virus and antibodies have not yet been perfected, it is also possible that these patients at some point tested "false negative" when in fact they had not rid themselves of the pathogen.

"That suggests that people remain infected for a long time -- several weeks," Balloux added. "That is not ideal."

Another pre-publication study that looked at 175 recovered patients in Shanghai showed different concentrations of protective antibodies 10 to 15 days after the onset of symptoms.

"But whether that antibody response actually means immunity is a separate question," commented Maria Van Kerhove, Technical Lead of the WHO Emergencies Programme.

"That's something we really need to better understand -- what does that antibody response look like in terms of immunity."

Indeed, a host of questions remain.

"We are at the stage of asking whether someone who has overcome COVID-19 is really that protected," said Jean-Francois Delfraissy, president of France's official science advisory board.

For Tangy, an even grimmer reality cannot be excluded.

"It is possible that the antibodies that someone develops against the virus could actually increase the risk of the disease becoming worse," he said, noting that the most serious symptoms come later, after the patient had formed antibodies.

For the moment, it is also unclear whose antibodies are more potent in beating back the disease: someone who nearly died, or someone with only light symptoms or even no symptoms at all. And does age make a difference?

Faced with all these uncertainties, some experts have doubts about the wisdom of persuing a "herd immunity" strategy such that the virus -- unable to find new victims -- peters out by itself when a majority of the population is immune.

"The only real solution for now is a vaccine," Archie Clements, a professor at Curtin University in Perth Australia, told AFP.

At the same time, laboratories are developing a slew of antibody tests to see what proportion of the population in different countries and regions have been contaminated.

Such an approach has been favoured in Britain and Finland, while in Germany some experts have floated the idea of an "immunity passport" that would allow people to go back to work.

"It's too premature at this point," said Saad Omer, a professor of infectious diseases at the Yale School of Medicine.

"We should be able to get clearer data very quickly -- in a couple of months -- when there will be reliable antibody tests with sensitivity and specificity."

One concern is "false positives" caused by the tests detecting antibodies unrelated to COVID-19.

The idea of immunity passports or certificates also raises ethical questions, researchers say.

"People who absolutely need to work -- to feed their families, for example -- could try to get infected," Balloux.

Comments

Add new comment

  • Coastaldigest.com reserves the right to delete or block any comments.
  • Coastaldigset.com is not responsible for its readers’ comments.
  • Comments that are abusive, incendiary or irrelevant are strictly prohibited.
  • Please use a genuine email ID and provide your name to avoid reject.
News Network
January 23,2020

Beijing, Jan 23: China is putting on lockdown a city of 11 million people considered the epicenter of the new coronavirus outbreak that has killed 17 and infected nearly 600 people, as health authorities around the world work to prevent a global pandemic.

The previously unknown coronavirus strain is believed to have emerged late last year from illegally traded wildlife at an animal market in the central Chinese city of Wuhan. Cases have been detected as far away as the United States, stoking fears the virus is already spreading worldwide.

Wuhan's local government said it would shut down all urban transport networks and suspend outgoing flights from the city as of 10 a.m. (0200 GMT) Thursday, state media reported, adding that the government is urging citizens to not leave the city in the absence of special circumstances.

Contrasting with its secrecy over the 2002-03 Severe Acute Respiratory Syndrome (SARS), which killed nearly 800 people, China's communist government has this time given regular updates to try to avoid panic as millions of people travel for the Chinese Lunar New Year holiday.

Chinese authorities have confirmed 571 cases and 17 deaths as of end-Wednesday, state television reported on Thursday. There are eight other known cases around the world - Thailand has confirmed four cases, while the United States, Taiwan, South Korea and Japan have each reported one.

Vice Premier Sun Chunlan said during a visit to Wuhan that authorities needed to be open about the spread of the virus and their efforts to contain it, the official Xinhua news agency reported on Thursday, comments likely to reassure global health experts.

After a meeting at its Geneva headquarters on Wednesday, the World Health Organization (WHO) said it would decide on Thursday whether to declare the outbreak a global health emergency, which would step up the international response.

If it does so, it will be the sixth international public health emergency to be declared in the last decade.

WHO Director-General Tedros Adhanom Ghebreyesus told reporters in Geneva that China's actions so far were "very strong" but called in Beijing to take "more and significant measures to limit or minimise the international spread".

"We stressed to them that by having a strong action not only they will control the outbreak in their country but they will also minimise the chances of this outbreak spreading internationally. So they recognise that," he said.

A senior U.S. State Department official also called on China to "play a bigger role in global health so they taking more and significant measures to limit or minimise the international spread".

"The lack of transparency in the past, especially with SARS ... gives us concern that that may be the case here," the official said, adding however that there were "positive signs that they have taken action in Wuhan".

Fears of a pandemic initially spooked markets but they regained their footing on Wednesday, with investors citing the robust response from authorities as reassuring.

VIRUS SPREADING

The outbreak began in Wuhan, a major transportation hub as well as central China's main industrial and commercial centre, and has now spread to other major population centers including Beijing, Shanghai and Hong Kong.

There is no known cure for the virus. Symptoms include fever, difficulty in breathing and cough, similar to many other respiratory illnesses, and can cause pneumonia.

Chinese authorities are still investigating the origins of the virus, though they confirmed the outbreak began at a market in Wuhan with illegal wildlife transactions and that it can spread from one person to another via respiratory transmission. Among confirmed patients are 15 medical workers, further adding to worries about a possible global pandemic.

Many Chinese were canceling trips, buying face masks, avoiding public places such as cinemas and shopping centers, and even turning to an online plague simulation game as a way to cope.

Airports globally stepped up screening passengers from China and the European Centre for Disease Control and Prevention (ECDC) said in a risk assessment that further global spread of the virus was likely.

Britain joined other countries including Australia in advising citizens against all but essential travel to Wuhan.

Comments

Add new comment

  • Coastaldigest.com reserves the right to delete or block any comments.
  • Coastaldigset.com is not responsible for its readers’ comments.
  • Comments that are abusive, incendiary or irrelevant are strictly prohibited.
  • Please use a genuine email ID and provide your name to avoid reject.