Why Ebola is back in Guinea and why the response must be different this time

The new reports of Ebola in Guinea are a source of anxiety given the history of the epidemic in West Africa from 2014-2016. It was the largest Ebola outbreak reported to date – 28,000 cases were recorded, including 11,000 deaths. It originated in Guinea and then spread to Sierra Leone and Liberia. The confirmed cases this time have been reported in south-eastern Guinea, about 800 km by road from the capital, Conakry, but just 100 km from various border points with Liberia and Côte d’Ivoire. The problem is that the virus could spread to other places in Guinea as well as to neighboring countries if it is not quickly contained. Jacqueline Weyer answers questions about the latest outbreak.

What has been done to prevent new outbreaks from developing since 2016?

The development, evaluation and licensing of Ebola vaccines and antivirals were major activities in the years following the 2014-2016 epidemic. Since then, two vaccines have been pre-approved by the World Health Organization (WHO) and registered with different regulatory bodies.

Read more: Ebola strikes West Africa again: key questions and lessons from the past

During the 2018-2020 Ebola epidemic in the Democratic Republic of the Congo (DRC), a number of countries in the region also established a national registration of these products. Nearly 50,000 people have been vaccinated as part of containment efforts in the DRC. Ring vaccination – the vaccination of individuals in a circle around cases – with the Ebola vaccine is a vital tool in preventing the spread of infection as it produces an immune barrier that disrupts the chain of transmission of the virus.

Why did the disease come back?

The natural cycle of virus transmission involves certain species of forest fruit bats. These act as a reservoir for the virus in nature and this cycle is continuous, ensuring that the virus is maintained in nature over time. The virus can, however, spread from its natural reservoir to other forest animals or directly to humans to trigger an epidemic in the human population.

Read more: Ebola vaccine essential in ongoing efforts to contain outbreak in DRC

Animals infected with Ebola such as non-human primates, monkeys and antelopes have already been reported and could present a source of exposure for humans. For example, hunters or people who kill these animals come into contact with infected blood and tissue. But, it is also believed that fallout can occur through direct contact from infected bats to humans. The exact mechanism remains to be defined, but contact with infected blood and tissue is likely a source of infection.

The virus is always present in nature and, when circumstances permit, it can pass from one species to another.

What lessons from previous outbreaks are currently being applied?

There are many important lessons, but no doubt quick and safe action will make the difference. In the aftermath of the 2014-2016 epidemic, the apparent delay in initial responses was a major criticism of response efforts.

Containing the epidemic early is critical before it spreads beyond zero point to other places in Guinea and neighboring countries. If this happens, longer and more complicated containment efforts will be required.

One feature that sets this outbreak apart is that it is occurring against the backdrop of the global COVID-19 pandemic – which is putting great strain on healthcare and other resources around the world.

Read more: The coping mechanisms that the DRC is putting in place in the face of Ebola, measles and COVID-19

International support has been a pillar of containment efforts in West Africa, but also in most of the Ebola outbreaks reported to date. Time will tell how the efforts to deal with the impact of the COVID-19 pandemic on Ebola containment efforts.

Does Guinea have the health infrastructure to manage the disease?

Access to health care in Guinea has improved slightly over the years. But the country is struggling with one of the worst healthcare infrastructure in the world. Most of the deaths in Guinea remain associated with communicable diseases, maternal and neonatal, and nutritional disorders. The 2014-2016 Ebola outbreak galvanized intensified efforts to improve health systems in the country, but progress is slow.

Given that the Ebola outbreak in West Africa ended only five years ago, it can be assumed that some of the infrastructure that was developed during the outbreak remains and could be quickly restored. in service. The “muscle memory” for the public health response to Ebola acquired during the previous epidemic in Guinea will be put to the test in the coming weeks.

What is the relationship between the epidemic in West Africa and Central Africa?

Studies conducted during and after the 2014-2016 epidemic show that the Zaire Ebolavirus the species was circulating in local bat populations in West Africa before the epidemic. The genomic similarity of the Ebola viruses associated with the West African epidemic and the Ebola viruses that have caused outbreaks in Central Africa since 1976 confirms the hypothesis that the virus at one point spread from the Central Africa to West Africa.

On the other hand, when analyzing the differences between these viruses, there is evidence of a distinct evolution in space and time. The exact mechanism of spread from Central Africa to West Africa remains uncertain. But the transfer is plausible given, for example, that many species of fruit bats – some of which are implicated as natural reservoirs of the Ebola virus – are migratory and can migrate great distances.

Efforts are underway to determine the genomic sequence of the virus associated with the recently reported cases. This could point to the potential source of the outbreak and indicate the link between these viruses associated with recent cases and viruses that circulated during the previous outbreak. Another consideration is that the currently available Ebola vaccines have not been tested against strains other than Zaire Ebolavirus. The efficacy of these vaccines against other species of the virus is therefore uncertain.

Jacqueline Weyer does not work, consult, own stock, or receive funding from any company or organization that would benefit from this article, and has not disclosed any relevant affiliation beyond her academic appointment.

By Jacqueline Weyer, Senior Medical Scientist, National Institute of Communicable Diseases