India issues Ebola Advisory: With the World Health Organization (WHO) Director-General, Dr Tedros Ghebreyesus, expressing deep concern about the speed and scale of the Ebola outbreak, the Union Health Ministry has notified screening norms and vigilance at airports and ports for those travelling from or transiting through the Democratic Republic of the Congo (DRC), Uganda and South Sudan.

Ebola is a zoonotic infection caused by the Orthoebolavirus family that can be extremely fatal in humans. It can spread from humans to humans through direct contact with infected fluids such as blood, saliva, sweat, tears, vomit, faeces, and breast milk among others. It can also be transmitted by touching contaminated surfaces and contact with dead bodies of those who have died of the infection. While most of the symptoms of the disease are like flu — fever, headache, muscle and joint pains — unexplained internal and external bleeding is one of the distinct features of the disease.

At the World Health Assembly in Geneva, Dr Ghebreyesus flagged how rapidly the virus had spread into major urban centres, including Kampala (Uganda) and Goma (DRC), the healthcare-associated transmission and the significant population movement across porous borders. Most approved vaccines target the Zaire ebolavirus, not the Bundibugyo or Sudan strains. The WHO says vaccines require about 10 to 14 days to generate a complete immune response. So, those exposed just before or shortly after vaccination can still develop the disease.

Dr Amesh Adalja, senior scholar at the Johns Hopkins University Center for Health Security and assistant professor – adjunct at the Johns Hopkins Bloomberg School of Public Health, however, says that “urban spread does not automatically mean sustained international spread”. He has been working on emerging infectious disease, pandemic preparedness and biosecurity.

Ebola seems to have crossed into urban centres in Kampala this time. Will this outbreak spread beyond regional containment? What does this mean in terms of future viral spreads?

The fact that Ebola cases have occurred in urban areas like Kampala is concerning because cities increase opportunities for transmission, complicate contact tracing and place stress on healthcare systems. Urban outbreaks are harder to control than rural outbreaks but urban spread does not automatically mean sustained international spread.

Ebola transmission still depends on close contact with infected bodily fluids, contaminated materials, or unsafe healthcare and burial practices. That transmission pattern makes Ebola fundamentally different from airborne respiratory viruses like influenza or SARS-CoV-2, which spread much more efficiently. Historically, even large Ebola outbreaks have generally remained regionally concentrated, though international exportation of cases can occur.

The reason infrastructure stays fragile despite all these crises comes down to what I call the panic-neglect cycle. When an outbreak ends, political attention and money evaporate. External responders flood in, contain the fire and leave without building anything durable. Local hospitals, lab networks and contact-tracing systems remain exactly as fragile as they were before. Rinse, repeat. COVID didn’t break this pattern; it just illustrated it at global scale.

There is a need to make countermeasures that cover all filoviruses. While strain specific countermeasures are critical, ultimately universal filovirus medications and vaccines are needed. However, there is work ongoing on Marburg, Ebola Sudan, and Ebola Bundibugyo countermeasures, the latter of which may see use during this outbreak.

Even if there is a vaccine for every strain, what is its efficacy?

Efficacy is very high for the Zaire strain vaccine and one can expect similar efficacy for other strain-specific vaccines as well.

Are climate and ecological disruption increasing spillover risk? Will every virus now have pandemic potential?

Not every virus has pandemic potential. In order for a virus to have pandemic potential, it has to spread efficiently between humans. Not all viruses have that biology.

Ecological disruption does increase contact between humans and other animal species and does a spillover risk. However, spillover risk does not equal pandemic.

Can outbreak surveillance become fast enough to stop transmission early? A lot depends on how quickly unusual clusters are detected.

Only if there is a fully supported integrated system that is operating all the time and provides prompt alerts. Especially, if it is focused on undiagnosed syndromes.

Can AI-supported surveillance help?

Yes, AI supported autonomic surveillance can do massive amounts of data analysis that can inform medical countermeasure development, epidemiology, and overall surveillance. 

Follow our daily newsletter so you never miss anything important. On Wednesday, we answer readers' questions.

With repeated outbreaks, will public trust improve or erode because any outbreak control depends heavily on community cooperation with isolation, tracing, and safe funeral practices?

There are many local factors that influence trust. If, during prior outbreak response, trust was built it will make it easier for future outbreaks. But nothing is guaranteed.

Are we getting better at preventing zoonotic outbreaks or just better at reacting after they start?

We have the tools and technology to master this problem. However, implementation remains the challenge.