The latest Ebola outbreak in the Democratic Republic of Congo began at least three months before it was officially declared - meaning the health authorities are still playing catch-up, the World Health Organization (WHO) has warned.

More than 1,900 people have died from the virus since that declaration on 15 May, making this the second-worst Ebola outbreak ever.

Infection rates are still high, adding to the concern that the authorities are struggling to get to grips with the spread of the disease.

The epicentre of this outbreak of the Bundibugyo species of Ebola, is in the east of DR Congo where insecurity has hampered control efforts.

There is also no approved vaccine or any recognised therapeutic drugs, making treating Bundibugyo harder.

"We are chasing the virus, the virus is ahead of us," WHO Africa director Dr Mohamed Janabi said at a news conference in the city of Bunia, which is at the heart of this outbreak.

He cited research showing that the virus started spreading in February and was initially misdiagnosed as malaria or typhoid.

Janabi also said that, in part because of insecurity, health workers are only reaching about 30% of the cases with the rest dying at home.

Traditional burial practices – where mourners touch the deceased's body - and a suspicion of health authorities in some communities have also made things difficult.

But there are now several dedicated treatment centres in the east of DR Congo and people are getting diagnosed much more quickly.

So far there have been 4,294 confirmed cases and 1,960 deaths, DR Congo's health ministry has said.

The largest recorded outbreak was in West Africa between 2014 and 2016 when 11,325 people died.