7 KEY QUESTIONS ON EBOLA

Ebola virus disease belongs to the Filoviridae family. “Filo” because it resembles a microscopic filament. The Ebola virus is one of the most deadly diseases on the planet. It ranks level 4 in the classification of infectious biological agents.




The Ebola virus comes in 5 strains :
Zaire ebola virus
Sudan ebola virus
Bundibugyo ebola virus
Reston ebola virus
Taï Forest virus

The first three are associated with human epidemics. The Zaire strain is responsible for the outbreak currently affecting West Africa.
The Reston and Taï Forest strains are not associated with major human epidemics, and no deaths have been reported to date. The Reston strain has been identified in the Philippines and in the People’s Republic of China, where it mainly affects monkeys and pigs.

THE ORIGIN OF THE 2014 EPIDEMIC
Although the origin of the virus is still unknown, fruit bats are considered to be the natural reservoir. The main carriers most likely to transmit the disease are gorillas, chimpanzees and antelopes. Contamination passes from animals to humans either through handling the flesh of these infected animals, or eating them, particularly if insufficiently cooked.

Two theories currently attempt to explain the origin of the 2014 epidemic :
1- According to a team of British researchers, a two-year-old Guinean child may be at the root of the epidemic.
2- Another study published in the journal Science attributes the start of the epidemic to a faith healer living in Sokoma, Sierra Leone close to the Guinean border.

This is the first time that the Ebola virus has struck urban zones. Population density fosters transmission and could be the main reason for the current rapid spread of the disease. Contrary to popular belief, recent mutations in the virus do not seem to be the cause. However, these mutations have modified the virus’s pathogenic nature. The death rate was 90% in 1976, compared to 50% to 70% now.



Ebola virus disease invades the infected person’s blood and cells. As the disease progresses, it generally attacks the vital organs, especially the kidneys and liver, and causes significant internal bleeding. Death can occur a short time after the first symptoms, caused by the failure of numerous organs and cardio-respiratory arrest.


HOW THE DISEASE EVOLVES :



Transmission between humans occurs from contact with the blood, secretions (sneezing) or biological liquids (saliva, blood, urine, faeces, vomit, sperm, sweat) of an infected person or via a contaminated environment.

A patient displaying symptoms of the disease at a health centre is placed in isolation. Once a diagnosis has been established, he or she receives treatment for secondary infections. Care workers attempt to find anyone with whom the sufferer has been in physical contact. All those who have touched him or her are then put in observation quarantine for 21 days and their temperature is checked daily. Once the observation period is over, in the absence of a fever, these people are considered as not infected.
WHO has stated that, "people who receive treatment fast can recover". In health centres, patients can receive care and support treatment throughout the course of the disease.

WHAT DOES AN EBOLA TREATMENT CENTRE LOOK LIKE ?
Move your mouse over the image to see the captions :

To date, no vaccine or certified medication exists to combat the Ebola virus disease.
Patients receive intensive care to treat the symptoms and secondary infections. Most are dehydrated and are either put on a drip or receive oral rehydration solutions.



Up till now, pharmaceutical laboratories had shown little interest in researching the Ebola virus because the disease was restricted to poor countries and had only infected a small number of people. However, the impressive progression of the 2014 epidemic has spurred international research and the World Health Organization has given experimental treatments the go-ahead.

WHO’s ethics experts have authorised clinical trials of unapproved treatments on certain conditions :
- total transparency of type of treatment
- freedom of choice and guaranteed confidentiality for patients
- involvement of local communities before using any therapy.

In early September, they examined 8 medications, devised to treat patients infected by Ebola and 2 vaccines aimed at prevention. These vaccines are currently being developed without following the usual authorisation process, which would take about ten years.

Although these medications have produced promising results in the laboratory, nothing guarantees that they will work, or that they will not have potentially dangerous side effects. For the time being, they are not widely available.

In early September, the 2014 epidemic had already caused four times more deaths than in 1976. The first Ebola outbreaks in Sudan and Zaire resulted in 431 deaths.

The last significant epidemic was in 2007. It affected Uganda in the Gulu region, and led to 224 people dying.

PREVIOUS EBOLA EPIDEMICS :



The current epidemic is developing simultaneously, involving several outbreaks that are often far from each other, in different countries and in urban zones. However, the virus strain which was active in DRC between the end of August and mid-November, is different from the strain in Guinea, meaning that this new outbreak was not a transfer of the Guinean epidemic.

The World Health Organization has declared Ebola virus disease an international public health emergency and adopted a global-scale action strategy.

Countries affected by at least one transmission
- Countries must declare a state of emergency and mobilise every possible means in their healthcare systems.
- They must also inform the population through, for example, village chiefs or religious representatives. The aim is to underline the basic safety principles.

Countries with one suspected or confirmed case or sharing borders with an affected country
- These countries must ensure close border surveillance and verify the temperature of all travellers transiting through international airports, ports and the main border checkpoints. In case of fever, the risk of Ebola must be assessed and the suspected person must be forbidden to travel.
- If the test for Ebola virus disease is positive, every possible confinement measure must be taken to prevent transmission, particularly medical surveillance of anyone who has been in contact with the sufferer.

WHO : http://www.who.int/csr/disease/ebola/en/
Institut Pasteur : http://www.pasteur.fr/en/institut-pasteur/news-institut-pasteur/institut-pasteur-and-institut-pasteur-dakar-front-line-against-ebola-crisis-west-africa
MSF : http://www.msf.org/diseases/ebola
RFI : http://www.english.rfi.fr/tag/ebola