The World Health Organisation (WHO) has declared the outbreak of Ebola in the eastern Democratic Republic of the Congo (DRC) a “public health emergency of international concern”, indicating that it represents a serious threat beyond that country’s borders.

By the end of last week there had been 746 suspected cases of the disease, along with 176 deaths in the DRC. (Subsequent statistics from the country put the number of cases at 867 and the number of deaths at 204.) A small number of cases have also been reported in neighbouring Uganda, typically of people who have a connection to the DRC. Health experts believe the real numbers may be higher, given the weaknesses of health and reporting systems in the affected areas.

The outbreak has primarily hit Ituri, North Kivu, and South Kivu provinces. Not only are these in the interior and far removed from the capital Kinshasa, but an insurgency is ongoing in these regions (South African troops were for many years deployed to North and South Kivu).

Jia Kangbai, a Sierra Leonean epidemiologist who has experience dealing with previous outbreaks of the disease, warns that there are four conditions that make arresting the spread of the virus difficult. The first is late detection. It can take time for the health system to become aware of a new pathogen, and more time for laboratories to verify what it is.

The second is misdiagnosis. Since the initial symptoms of Ebola can resemble those of other diseases such as malaria, medical workers can mistake what they are seeing when patients present themselves for treatment. This occurred during the Ebola outbreak in West Africa in 2013, where Ebola was mistaken for Lassa fever.

The third is cultural demands, particularly funeral rites, which demand that family and friends handle bodies. This was another driver of the West African outbreak, and looks to be a major risk in the current one: already there have been instances of aggrieved communities attacking isolation and body storage facilities in the DRC – notably at Rwampara hospital, near the city of Bunia in Ituri province, where a mob torched tents being used as isolation wards after the hospital refused to release a body for burial.

Together, all of this creates windows of vulnerability in which the highly contagious disease is able to spread ahead of any efforts to contain it.

The fourth condition is a shortage of funds to deal with the outbreak. This is primarily due to the reduction of support from the United States following the dissolution of USAID – the United States Agency for International Development. The body had played an important role in bolstering domestic institutions in West Africa during its outbreak and had ensured that valuable supplies and expertise were available.

Moreover, the currently active strain of the virus, Bundibugyo, is a rare one, and measures to deal with it need to be developed.

The WHO, medical charities, and a number of donor countries have stepped up efforts to assist in dealing with the outbreak. Researchers at Oxford University are working on a vaccine for the strain, though this will likely take months. When ready, it will probably be manufactured in India.

The African Centres for Disease Control and Prevention cautions that ten other countries could be vulnerable to an outbreak: Angola, Burundi, the Central African Republic, the Republic of the Congo (Brazzaville), Ethiopia, Kenya, Rwanda, South Sudan, Tanzania, and Zambia. South Africa is not considered vulnerable, although the possibility of cases occurring in the country cannot be totally ruled out.

The West African Ebola outbreak between 2013 and 2016, centred on Guinea, Liberia, and Sierra Leone (with linked cases recorded in Mali, Senegal, Nigeria, Europe, and the United States), registered 28 646 cases, and claimed 11 323 lives.