A treatment for Ebola is a step closer with the launch of the first ever clinical trial of experimental drugs during an active outbreak of the disease.

Some 160 patients in the Democratic Republic of Congo (DRC) have already been treated with the experimental therapies but a clinical trial will enable researchers to work out which drugs are the most effective.

This is the first time therapies have been available during an outbreak of the deadly haemorrhagic fever – previously, health care professionals had only been able to treat the symptoms of the disease.

The drugs that will be tested are Mab 114, Regeneron, Remdesivir and ZMapp. ZMapp in particular is challenging to administer, with patients needing an intravenous infusion and constant monitoring to ensure that they are getting the correct dose.

Experts are struggling to bring this latest outbreak of Ebola in DRC under control. More than 100 armed groups are active in the area and attacks have prevented health experts from being able to trace and treat suspected patients.

Vaccinating contacts – and the contacts of contacts – of patients with suspected Ebola is another key part of the response and this too has been hampered by security concerns.

The latest figures from the World Health Organization show that since the outbreak was declared in August 412 people have caught the disease, 236 of whom have died.