No 51 - 2014

Update on the ebola virus outbreak

Update on the ebola virus outbreak

The outbreak of ebola virus disease (EVD) in West Africa continues. The latest WHO update published on 15 December 2014 reports a total of 18,464 cases and 6,841 deaths in the three most severely affected West African countries of Guinea (2,394 cases/1,518 deaths), Liberia (7,797 cases/3,290 deaths) and Sierra Leone (8,273 cases/2,033 deaths). Studies indicate the existence of a considerable "dark figure" suggesting that the real number of cases may be up to 2-3 times higher.

Additionally, the disease has spread to three other West African countries: Nigeria (20 cases/8 deaths), Senegal (1 case), Mali (8 cases/6 deaths) and to two countries outside of Africa: Spain (1 case) and the USA (4 cases/1 death). Nigeria, Senegal and Spain have been declared ebola-free, and there are no signs of current spreading to Mali or the USA.

Status quo in West Africa

Since the beginning of October, Guinea has seen a slightly increasing trend as between 75 and 148 new cases have been recorded weekly, but inter-regional variation within Guinea has been considerable. The incidence increases in the area around the capital of Conakry, and sustained spreading of the virus in the central and northern parts of the country entails a risk that patients seek north across the border to the neighbouring countries, e.g. Mali, for treatment.

In Sierra Leone, transmission of the infection remains intense. In the first week of December, a total of 397 new confirmed cases were detected, which is more than three times as many as recorded in the two remaining West African countries together. The most severely affected area is that surrounding the capital of Freetown, from where approx. 1/3 of all new cases have been reported, but extensive spreading has been recorded in all parts of the country, apart from the south.

In Liberia, a decreasing trend has been observed over the past 4 weeks. Nevertheless, approx. 100 new cases have been detected in the first 9 days of December, and the primary infection area is currently that surrounding the capital of Monrovia.

You can follow the outbreak as it evolves in this special ebola theme at the SSI's website (In Danish language).

Disease among healthcare workers

Throughout the outbreak, a considerable number of cases have been observed among healthcare workers. As per 7 December 2014, a total of 639 cases had been reported, including 349 deaths. Healthcare workers therefore constitute approx. 3.5% of all reported cases. The overwhelming majority (622 cases/342 deaths) were from the three most severely affected countries, but cases were also recorded among healthcare workers from Mali (2), Nigeria (11), Spain (1) and the USA (3). The WHO has performed thorough investigations to determine the source of the infection. Preliminary results indicate that a considerable share of the healthcare staff in the epicentre of the epidemic were not infected in the dedicated EVD treatment centres. This underlines the importance of observing strict hygienic precautions at all visitation and treatment sites that receive patients on suspicion of EVD and not only at dedicated EVD treatment centres. Access to personal protection equipment and thorough and mandatory introduction to and training in the use of such equipment is considered essential for the protection of both healthcare workers and patients.

The international UN/WHO handling of the outbreak

In August, the WHO declared the outbreak a Public Health Emergency of International Concern, EPI-NEWS 33/14, and that triggered the first-ever UN mission in response to a public health emergency (UN Mission for Ebola Emergency Response/UNMEER). The strategic priorities of the UNMEER are to stop the spreading of the disease, treat the infected patients, ensure other healthcare services, maintain stability in the countries and prevent spreading of EVD to other countries. The WHO cooperates with other international organisations such as the International Red Cross in this mission, which is implemented in collaboration with the relevant national healthcare authorities. The WHO alone has raised a total of 187 million US $ to fight the epidemic, but estimates that an additional 32 million US $ are required.

Objectives for the efforts made

To facilitate monitoring of the implementation of the considerable efforts made in the affected areas, a number of key indicators were established and objectives for the fulfilment of these indicators were defined. Mathematical models have e.g. demonstrated that the epidemic curve is expected to decline when 70% of all EVD cases are isolated, and 70% of those who die from ebola are buried safely. This was also the UNMEER's 60-day objective as per 1 December 2014, and it is expected that this target will have been fulfilled in most districts. As per 1 January 2015, the target is to be able to isolate and treat all EVD patients and to have the capacity to provide a safe (and dignified) burial for all fatal EVD cases. Even though the first target on the 70% isolation rate has been reached at the national level, an uneven distribution of EVD cases and dedicated treatment beds means that the local treatment capacity is insufficient in some places. Simultaneously, there may be unused beds in the dedicated EVD treatment centres in other districts.

It has been ensured that all 53 districts of the 3 countries where EVD cases have been detected have access to laboratories that can receive a patient sample within 24 hours after it was sampled. Furthermore, there are 19 laboratories capable of performing EVD diagnostics, and these are more or less equally distributed across the three countries.

Additionally, routines have been established ensuring that people who have had contact to infected persons are seen daily for temperature measurements and screening for symptoms, and currently this measure has been implemented for 84-94% of contacts. This figure is impressive as 6-22 contacts have been identified for every patient, and every contact needs to be seen daily for a period of 21 days.

Furthermore, several hundred burial teams have been established to ensure safe and dignified burial of EVD patients. By the end of November, 77-83% of the planned burial teams were in place. Simultaneously, considerable dissemination efforts are made to stop the traditional physical contact with the deceased as these individuals are handled and washed before being buried.

Danish efforts

In the course of the autumn of 2014, the Danish Government has donated a total of 190 million DKK to assist in the fight against the EVD outbreak. Additionally, a substantial number of healthcare workers have contributed personally through their work in West Africa in difficult conditions and putting their own health at risk. This includes persons deployed by the Danish Emergency Management Agency, the Red Cross and volunteers working for Doctors Without Borders. In the autumn of 2014, Statens Serum Institut has also had two EPIET/EUPHEM fellows stationed in Liberia for an overlapping 10-week period during which they contributed to improve the epidemiological registration of patients and contacts in the country.


The unparalleled outbreak in West Africa has clearly outlined the possible consequences of introducing a disease, which - in controlled circumstances is not particularly infectious - into societies with fundamentally weak healthcare systems and traditional rituals on the handling and burial of deceased persons. Even though the official figures on the scope of the epidemic are underestimated, the worst case scenarios that were predicted by several models on infection spreading earlier this autumn have not come true. But the predictions/projections placed the ebola outbreak on the international agenda and have thus paved the way for several of the WHO objectives for the efforts made.

The current epidemiological development, particularly in Liberia, and the reached outbreak control indicators give rise to weak optimism, but many more months will pass before the outbreak has been fully curbed. Even though it seems that progress is being made measured by the selected indicators, uncertainty remains with regard to the quality and completeness of the epidemiologic monitoring of EVD cases. Presumably, some EVD cases still die and are buried without the knowledge of the healthcare authorities in some areas. The EVD epidemic has therefore been characterised as hundreds of epidemics that each run their own course and while the situation may be under control in one local area, a more critical situation may present in a neighbouring area. One particular challenge is the very mobile populations in these West African countries, where considerable cross-border travelling activity between cities takes place. This means that areas where EVD was previously under control may see new introductions of infectees.

The ebola vaccine candidates that have been in the pipeline for a long period of time, the development and testing of which have been accelerated due to the current West African outbreak, will hardly contribute decisively to curbing this outbreak, but in conjunction with classic counter infection measures such as isolation of diseased persons and tracking/monitoring of contacts, they will be very important in the efforts to rapidly limit and end future EVD outbreaks.
(P.H. Andersen, K. Mølbak, T.G. Krause, Department of Infectious Disease Epidemiology)

Merry Christmas & Happy New Year

Unless special circumstances arise, EPI-NEWS will not be published until week 2, 2015. The editorial team wishes everyone a merry Christmas and a happy New Year.
(Department of Infectious Disease Epidemiology)

Link to previous issues of EPI-NEWS

17 December 2014