Obama nominates Richard Verma as new US envoy to India

Houston, Mar 15: Researchers, studying the novel coronavirus, have found that the time between cases in a chain of transmission is less than a week, and over 10 per cent of patients are infected by someone who has the virus, but does not show symptoms yet, a finding that may help public health officials contain the pandemic.

The study, published in the journal Emerging Infectious Diseases, estimated what's called the serial interval of the coronavirus by measuring the time it takes for symptoms to appear in two people with the virus -- the person who infects another, and the infected second person.

According to the researchers, including those from the University of Texas at Austin, the average serial interval for the novel coronavirus in China was approximately four days.

They said the speed of an epidemic depends on two things -- how many people each case infects, and how long it takes cases to spread.

The first quantity, the scientists said, is called the reproduction number, and the second is the serial interval.

Due to the short serial interval of the disease caused by the coronavirus -- COVID-19 -- they said, emerging outbreaks will grow quickly, and could be difficult to stop.

“Ebola, with a serial interval of several weeks, is much easier to contain than influenza, with a serial interval of only a few days,” said Lauren Ancel Meyers, study co-author from UT Austin.

Meyers explained that public health responders to Ebola outbreaks have much more time to identify and isolate cases before they infect others.

“The data suggest that this coronavirus may spread like the flu. That means we need to move quickly and aggressively to curb the emerging threat,” Meyers added.

In the study, the scientists examined more than 450 infection case reports from 93 cities in China, and found the strongest evidence yet that people without symptoms must be transmitting the virus -- known as pre-symptomatic transmission.

More than one in ten infections were from people who had the virus but did not yet feel sick, the scientists said.

While researchers across the globe had some uncertainty until now about asymptomatic transmission with the coronavirus, the new evidence could provide guidance to public health officials on how to contain the spread of the disease.

“This provides evidence that extensive control measures including isolation, quarantine, school closures, travel restrictions and cancellation of mass gatherings may be warranted,” Meyers said.

The researchers cautioned that asymptomatic transmission makes containment more difficult.

With hundreds of new cases emerging around the world every day, the scientists said, the data may offer a different picture over time.

They said infection case reports are based on people's memories of where they went and whom they had contact with, and if health officials move quickly to isolate patients, that may also skew the data.

“Our findings are corroborated by instances of silent transmission and rising case counts in hundreds of cities worldwide. This tells us that COVID-19 outbreaks can be elusive and require extreme measures,” Meyers said.

Jan 23: Hundreds of Central Americans trying to reach the United States were stuck at the Mexico-Guatemala border on Wednesday after the Mexican government beefed up security to meet US demands to contain migrant flows.

Under sustained pressure from President Donald Trump, Mexico's government has adopted tougher measures to reduce the number of people heading towards the U.S. border.

Migrants in Tecun Uman, on the Guatemalan side of the border, were taken by surprise.

"We thought we'd be allowed through just like with the October caravan when they reached Tijuana," said Honduran migrant Ritzy Anabel, who did not give her surname.

"People from Mexico and Guatemala treated them well. But now it's changed because Mexicans don't want (us) to enter."

Many Central Americans migrants heading north are fleeing economic hardship and violence at home. A large caravan of migrants crossed into Mexico and went north in October 2018. Migrants crossing into Mexico earlier this week faced tear gas from security forces, who delivered a firmer response than in previous mass movements at the border.

Even so, about 1,000 migrants, most of them from Honduras, managed to reach Mexican soil on Tuesday. Mexican Foreign Minister Marcelo Ebrard said several hundred of the new arrivals were immediately deported on planes and buses.

On Wednesday, Mexican authorities said that 460 Honduran migrants were deported throughout the day. Other migrants from the group, including families traveling with children, were pondering their next moves.

Honduran Carlos Amador said that while some of his compatriots were returning home, others were hoping for positive news.

Trump has repeatedly threatened to punish Mexico and Central American countries if they fail to clamp down on the migrant flows. That has resulted in a series of agreements aimed at delivering on Trump's campaign promises to curb immigration.

Department of Homeland Security Acting Secretary Chad Wolf called the measures put in place by the Mexican National Guard "effective", adding that dozens of his personnel was on the ground in Central America assisting local immigration and security officials. Trump tweeted: "Sorry, if you come you will be immediately sent back!"