"Although we do not have solid figures showing health conditions of North Korea, medical experts assume that parasite infection problems and serious health issues have been prevalent in the country", said Choi Min-Ho, a professor at Seoul National University College of Medicine who specialises in parasites.
"The paper said that several officials confirmed that the disruption efforts include another, more sophisticated attempt at the kind of cyber and electronic strikes that former President Barack Obama ordered in 2014 when he intensified his efforts to cripple North Korea's missile testing". It has not tested a missile since firing one over Japan on Sept 15.
A North Korean delegation led by its top diplomat left for Cuba Friday, the North's state media reported, in an apparent search of an ally amid global sanctions further isolating the communist North.
President Trump echoed Mattis' stance while visiting South Korea as part of a 12-day trip to Asia last week, urging North Korea to "make a deal", while also warning Pyongyang to "not underestimate us" and "not try us".More news: Saudi Arabia pushing Israel into war with Hezbollah and Iran
Parasitic worms were also once common in South Korea 40 to 50 years ago, Lee noted during his briefing, but have all but disappeared as economic conditions greatly improved.
US Defense Secretary James Mattis reportedly said on Thursday that a current lull in Pyongyang's nuke and missile tests could be construed as an "opportunity" for peace talks with the US, according to a story on news website military.com.
"So long as they stop testing, stop developing, they don't export their weapons, there would be opportunity for talks", Mattis told reporters on a military plane on Thursday.
Satellite images taken this month of a North Korean naval shipyard indicate that Pyongyang is pursuing an "aggressive schedule" to build its first operational ballistic missile submarine, a United States institute has reported.
China's Song is officially traveling to North Korea to update officials there on the outcome of China's recent party congress.More news: LeBron James took shot at Phil Jackson not Frank Ntilikina
North Korea's main newspaper, Rodong Sinmum, continued the country's hard stance on negotiations with the United States on Friday.
Trump, who wants China to play a bigger role in pressuring North Korea to end its nuclear program, reacted to the announcement of the visit by calling it a "big move". It said in a commentary that Pyongyang will not put issues directly linked to its core interests and its people's security on the negotiation table.
Mr Trump wouldwill announce next week whether the USA will return North Korea to a list of state sponsors of terrorism, White House press secretary Sarah Huckabee Sanders said.
North Korea could not consider abandoning its nuclear programme, he said, adding: "This is the deterrent, the nuclear deterrent to cope with the nuclear threat from America".More news: Apple expected to be launching a redesigned iPad as early as 2018