Global health experts are urging the Donald Trump administration to allow US government disease specialists - "some of the world's most experienced" - to return to northeastern Democratic Republic of Congo to help fight the second-largest Ebola outbreak in history.The US experts have been sidelined for weeks, ordered away from the region because of State Department security concerns. New statements in two top medical journals this week are calling on the US to change its mind and send them back where they are sorely needed.This Ebola outbreak is like no other, as health workers compare the region to a war zone. Dozens of armed rebel groups are active, and their deadly attacks have forced responders to pause crucial containment work for days. Many new cases have been unrelated to known infections, alarming evidence that gaps in tracking remain.Late on Thursday, officials declared this outbreak second only to the devastating West Africa one that killed more than 11 000 from 2014-2016.DRC's health ministry said the number of confirmed and probable cases has reached 426, edging past the Uganda outbreak in 2000. So far this outbreak has 198 confirmed deaths and 47 probable ones."It is in US national interests to control outbreaks before they escalate into a crisis," one group of global health experts said in the Journal of the American Medical Association.A separate statement in the New England Journal of Medicine said : "Given the worsening of the outbreak, we believe it's essential that these security concerns be addressed and that CDC staff return to the field."It is not clear how many Centres for Disease Control and Prevention workers are now forced to tackle the outbreak from DRC's capital, Kinshasa, nearly 1 600km away.A State Department official said that CDC experts - and those with the US Agency for International Development, also affected by the order - continue to work closely with international partners to stop the outbreak.Security concerns are real, Ebola responders say. Teams with the World Health Organisation and DRC's health ministry venture out on virus containment missions accompanied by UN peacekeepers or other armed security in areas where gunfire echoes daily.Given the complications, this outbreak will last at least another six months before it can be contained, WHO emergencies chief Dr Peter Salama has predicted.Despite the challenges, Ebola responders have made breakthroughs that have given new hope in the fight against one of the world's most notorious diseases. More than 37 000 people have received Ebola vaccinations, and DRC has begun the first-ever trial to test the effectiveness and safety of four experimental Ebola drugs.Speaking to The Associated Press on Friday from the outbreak zone, the Ebola response program director for the International Rescue Committee, Dr. Stacey Mearns, said the absence of the CDC's experts can be felt acutely. Her colleague Dr. Mesfin Teklu Tessema, the IRC's senior health director, was among the more than two dozen people who signed the statement published in JAMA on Thursday."If the (US) ban were not in place the CDC would have a big and growing presence here," said Mearns, who worked closely with the CDC in the West Africa outbreak.The US sent thousands of responders to West Africa from the CDC and other parts of government, including the military.The CDC's experts have rich experience in surveillance, treatment and lab testing, Mearns said, adding that some of that work is now being done from afar."We haven't seen the height of this outbreak," she warned as Ebola continues to move into new areas in DRC, worrying close to a heavily traveled border with Uganda. "If want to see the end of this, we do need all critical actors on the ground." * Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.