Ebola can no longer be called an incurable disease, scientists have said, after two of four drugs being trialled in the major outbreak in the Democratic Republic of the Congo were found to have significantly reduced the death rate.

• ZMapp, used during the massive Ebola epidemic in Sierra Leone, Liberia and Guinea, has been dropped along with Remdesivir after two monoclonal antibodies, which block the virus, had substantially more effect, said the World Health Organization.
• The trial in the DRC, which started in November, has now been stopped. All Ebola treatment units will now use the two monoclonal antibody drugs.
• Now that 90% of their patients can go into the treatment centre and come out completely cured, they will start believing it and building trust in the population and community .
• The overall mortality of those given ZMapp in the trial in four centres was 49% while that of Remdesivir was 53%. A monoclonal antibody drug made by Regeneron had the lowest overall death rate, at 29%, while the monoclonal antibody 114 made by Ridgeback Biotherapeutics had a mortality rate of 34%.
• But the results in people who arrived at a treatment centre soon after they became sick, rather than staying at home, were even more impressive – with death rates of 24% on ZMapp, 33% with Remdesivir, 11% with 114 and just 6% with Regeneron’s drug.

Ebola virus-

• EVD first appeared in 1976 in 2 simultaneous outbreaks, one in what is now Nzara, South Sudan, and the other in Yambuku, DRC. The latter occurred in a village near the Ebola River, from which the disease takes its name.
• The virus family Filoviridae includes three genera: Cuevavirus, Marburgvirus, and Ebolavirus. Within the genus Ebolavirus, six species have been identified: Zaire, Bundibugyo, Sudan, Taï Forest, Reston and Bombali. The virus causing the current outbreak in DRC and the 2014–2016 West African outbreak belongs to the Zaire ebolavirus species.

Transmission

Natural host-

• It is thought that fruit bats of the Pteropodidae family are natural Ebola virus hosts.

Transmission to human-

•  close contact with the blood, secretions, organs or other bodily fluids of infected animals such as fruit bats, chimpanzees, gorillas, monkeys, forest antelope or porcupines found ill or dead or in the rainforest.

Human to human transmission

Ebola then spreads through human-to-human transmission via direct contact (through broken skin or mucous membranes) with:

• Blood or body fluids of a person who is sick with or has died from Ebola
• Objects that have been contaminated with body fluids (like blood, feces, vomit) from a person sick with Ebola or the body of a person who died from Ebola

Health-care workers have frequently been infected while treating patients with suspected or confirmed EVD. This occurs through close contact with patients when infection control precautions are not strictly practiced.

Burial ceremonies that involve direct contact with the body of the deceased can also contribute in the transmission of Ebola.

People remain infectious as long as their blood contains the virus.

Symptoms

The incubation period, that is, the time interval from infection with the virus to onset of symptoms, is from 2 to 21 days. A person infected with Ebola cannot spread the disease until they develop symptoms. 

Symptoms of EVD can be sudden and include:

• Fever
• Fatigue
• Muscle pain
• Headache
• Sore throat

This is followed by:

• Vomiting
• Diarrhoea
• Rash
• Symptoms of impaired kidney and liver function
• In some cases, both internal and external bleeding (for example, oozing from the gums, or blood in the stools).
• Laboratory findings include low white blood cell and platelet counts and elevated liver enzymes.

Diagnosis

It can be difficult to clinically distinguish EVD from other infectious diseases such as malaria, typhoid fever and meningitis. Confirmation that symptoms are caused by Ebola virus infection are made using the following diagnostic methods:

• antibody-capture enzyme-linked immunosorbent assay (ELISA)
• antigen-capture detection tests
• serum neutralization test
• reverse transcriptase polymerase chain reaction (RT-PCR) assay
• electron microscopy
• ·virus isolation by cell culture.

Vaccines

An experimental Ebola vaccine proved highly protective against EVD in a major trial in Guinea in 2015. The vaccine, called rVSV-ZEBOV, was studied in a trial involving 11 841 people. Among the 5837 people who received the vaccine, no Ebola cases were recorded 10 days or more after vaccination. In comparison, there were 23 cases 10 days or more after vaccination among those who did not receive the vaccine.

The rVSV-ZEBOV vaccine is being used in the ongoing 2018-2019 Ebola outbreak in DRC.