SHANGHAI/BEIJING (Reuters) - China will start releasing information from Wednesday on coronavirus patients who show no disease symptoms, ordering them into quarantine for 14 days, a health official said, after the mainland witnessed its first rise in infections in five days.

As local infections peter out and new cases surface among travelers returning home, the existence of virus carriers with no symptoms is fuelling public concern that people could be spreading it without knowing they are ill.

From April 1, the daily report of the National Health Commission will include details of such cases for the first time, Chang Jile, a commission official, told a briefing. People in close contact with them face 14 days of medical observation.

Asymptomatic patients under observation numbered 1,541 by Monday, with 205 of the cases having come from overseas, the commission said separately.

Monday's 48 new infections, and one death, in mainland China were up from 31 the previous day, the commission said, reversing four days of declines. All were imported, taking China's tally of such cases to 771, with no new local infection reported.

Many were students returning from overseas. About 35 infected Chinese citizens are still studying abroad, with 11 already cured, education ministry official Liu Jin said.

Photos: In Beijing, First Signs of Recovery View All 20 Images

COLLEGE EXAM

Fearing a second wave of infections sparked by such inbound travelers, China will delay its college entrance exam by a month, until July 7 and 8, China Central Television said, although Hubei province, where the virus emerged late last year, and Beijing, the capital, will get more leeway in scheduling it.

The annual two-day "gaokao" test drew more than 10 million candidates last year, state media have said.

Last week, a study in British medical journal the Lancet Public Health recommended that China extend school and workplace closures, since an earlier relaxation of curbs could bring a second peak in the outbreak by August.

"China has slowed transmission of the virus and in so doing, has passed one peak in the outbreak," said Tarik Jasarevic, a representative of the World Health Organisation. "The challenge now is to prevent a resurgence of new cases."

Tax authorities acknowledged the pandemic's impact on exporters, saying they were studying policies to reduce pressure on businesses, from tax cuts to an extension of preferential policies for foreign firms.

New data from a survey of manufacturers showed that factory activity expanded in March from February's collapse as businesses returned to work, but analysts warned that slumping external demand could prevent a durable recovery.

"The situation could be very fluid as the virus outbreak remains unpredictable," analysts at ANZ bank said in a note. "Chinese policymakers will likely step up and expand the stimulus program if needed."

The commercial hub of Shanghai saw 11 new imported cases on Monday, mainly among returning Chinese nationals, while Beijing had three.

Wuhan, the capital of central Hubei province, reported no new infections for a seventh straight day. Groups of medical teams in brightly colored jackets took photographs around the city as they prepared to leave.

"Thank you, Wuhan. We are back," read a message on a building that houses a Levi's clothing store.

By Monday, total infections stood at 81,518 in mainland China, with 3,305 deaths.

Interactive graphic tracking global spread of coronavirus: https://graphics.reuters.com/CHINA-HEALTH-MAP/0100B59S39E/index.html

(Reporting by Ryan Woo, Brenda Goh, Se Young Lee, Lusha Zhang, Andrew Galbraith, Roxanne Liu, Winni Zhou, Yew Lun Tian, Liangping Gao and Tom Daly; Additional reporting by Stephanie Nebehay in Geneva; Editing by Stephen Coates and Clarence Fernandez)