Syria-bound Russian military jet crashes with 92 onboard

Feb 22: A 20-year-old Chinese woman from Wuhan, the epicentre of the coronavirus outbreak, travelled 400 miles(675 km) north to Anyang where she infected five relatives, without ever showing signs of infection, Chinese scientists reported on Friday, offering new evidence that the virus can be spread asymptomatically.

The case study, published in the Journal of the American Medical Association, offered clues about how the coronavirus is spreading, and suggested why it may be difficult to stop.

"Scientists have been asking if you can have this infection and not be ill? The answer is apparently, yes," said Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical Center, who was not involved in the study.

China has reported a total of 75,567 cases of the virus known as COVID-19 to the World Health Organization (WHO) including 2,239 deaths, and the virus has already spread to 26 countries and territories outside of mainland China.

Researchers have reported sporadic accounts of individuals without any symptoms spreading the virus. What's different in this study is that it offers a natural lab experiment of sorts, Schaffner said.

"You had this patient from Wuhan where the virus is, travelling to where the virus wasn't. She remained asymptomatic and infected a bunch of family members and you had a group of physicians who immediately seized on the moment and tested everyone."

According to the report by Dr Meiyun Wang of the People's Hospital of Zhengzhou University and colleagues, the woman travelled from Wuhan to Anyang on Jan. 10 and visited several relatives. When they started getting sick, doctors isolated the woman and tested her for coronavirus. Initially, the young woman tested negative for the virus, but a follow-up test was positive.

All five of her relatives developed COVID-19 pneumonia, but as of Feb. 11, the young woman still had not developed any symptoms, her chest CT remained normal and she had no fever, stomach or respiratory symptoms, such as cough or sore throat.

Scientists in the study said if the findings are replicated, "the prevention of COVID-19 infection could prove challenging."

Key questions now, Schaffner said, are how often does this kind of transmission occur and when during the asymptomatic period does a person test positive for the virus.

May 20: The novel coronavirus is behaving differently in patients in northeast China who have contracted it recently compared with early cases, indicating it is changing as it spreads, a prominent doctor said.

China, which has largely brought the virus under control, has found new clusters of infections in the northeastern border provinces of Jilin and Heilongjiang in recent weeks, raising concern about a second wave.

Qiu Haibo, an expert in critical care medicine who is part of a National Health Commission expert group, said the incubation period of the virus in patients in the northeast was longer than that of patients in Wuhan, the central city, where the virus emerged late last year.

COVID-19 Pandemic Tracker: 15 countries with the highest number of coronavirus cases, deaths

"This causes a problem, as they don't have any symptoms. So when they gather with their families they don't care about this issue and we see family cluster infections," Qiu told state broadcaster CCTV in a programme broadcast late on Tuesday.

Patients in the northeastern clusters were also carrying the virus for longer than earlier cases in Wuhan, and they were taking longer to recover, as defined by a negative nucleic acid test, he said.

Patients in the northeast also rarely exhibited fever and tended to suffer damage to the lungs rather than across multiple organs, he said.

He said the virus found in the northeastern clusters was probably imported from abroad, which could account for the differences.

He did not say where he though they might have come from but both Jilin and Heilongjiang border Russia.

China reported five new coronavirus cases on Wednesday, down from six a day earlier.

Four of the new cases were local transmissions and one was imported by a traveller coming from abroad, the commission said in a statement, compared with three imported cases reported the previous day.

China's total number of coronavirus infections stands at 82,965, while the death toll 4,634. 

Feb 4: Americans on Monday kicked off the first vote of the 2020 presidential race as the midwestern state of Iowa began its caucuses, the closely-watched first step in deciding which Democrat will face incumbent Donald Trump in November's election.

The two frontrunners, left-wing Senator Bernie Sanders and former Vice President Joe Biden face a key test in the sparsely populated state, with a handful of others looking to make their mark to give their campaigns momentum.

The Iowa vote is a critical early look at the viability of the 11 Democratic candidates still in the race - even though just 41 Iowa delegates are up for grabs, a fraction of the 1,991 needed to secure the party nomination in July.

Iowa Democrats filed into nearly 1,700 caucus sites - schools, libraries, churches, mosques and meeting halls with Sanders and Biden in the lead in the state, followed by former South Bend, Indiana mayor Pete Buttigieg and Senator Elizabeth Warren, who is also on the left of the party.

But polling has fluctuated and Iowa's quirky caucus system - where voting is not by secret ballot but by public declaration for a candidate - makes the night hard to predict.

Luke Elzinga, a volunteer for Sanders, appeared early at Lincoln High School in Des Moines which was converted into a caucus location.

"I think he really inspires a lot of young people, a lot of disaffected voters who might not otherwise turn out," Elzinga, 28, told AFP news agency shortly before the caucusing began.

"And so I think he's the best candidate to beat Trump."

Three candidates - Sanders, Warren and Amy Klobuchar - have faced the unprecedented scenario of spending much of the past two weeks tethered to Washington for the impeachment trial of Trump instead of on the campaign trail in Iowa.

Even as candidates sought to make 11th-hour impressions on undecided voters, the senators were obligated to return to Washington for the trial's closing arguments on Monday.

Defeating Trump

In a vote scheduled for Wednesday, Trump is almost certain to be acquitted by the Republican-led upper house on charges of abuse of power and obstruction of Congress.

For Democrats, second-tier hopefuls Klobuchar and tech entrepreneur Andrew Yang look to outpace expectations and seize momentum heading into the next contest in New Hampshire on February 11.

Earlier on Monday Biden - who still holds the lead in national polls - brought pizza to a field office in a strip mall near Des Moines to thank volunteers.

"I'm feeling good about today," he said.

Like many candidates, Biden spent the weekend crisscrossing Iowa in a final push to convince undecided voters he is best placed to accomplish Democrats' number one goal: defeating Trump.

The president has not stood idly by. On Sunday he branded Biden "Sleepy Joe" and described Sanders as "a communist," previewing a likely line of attack were Sanders to win the nomination.

Unlike secret ballot voting, caucus-goers publicly declare their presidential choice by standing together with other supporters of a candidate.

Candidates who reach 15 percent support earn delegates for the nomination race while supporters of candidates who fall short can shift their allegiance to others.

Turnout is critical, and candidates and their representatives will seek to persuade voters on issues including healthcare, taxes and ending Washington corruption.

One key candidate who has opted not to contest in Iowa is billionaire businessman Michael Bloomberg, who entered the race in November but has surged into fourth place in RealClearPolitics' national polling average.

The former New York mayor, who has spent more than $300m on advertising, according to Advertising Analytics, is focused on running a national campaign with particular emphasis on states that vote on "Super Tuesday," on March 3.