In recent weeks, the phrase "Nipah virus – a new pandemic threat" has appeared in the media. This virus, identified nearly 30 years ago in several Asian countries (Malaysia, India, Bangladesh), is transmitted by fruit bats and generally causes fatal pneumonia or encephalitis. Nipah is the name of a small town in Malaysia where the first case of the disease caused by this virus was recorded. To date, the total number of identified Nipah virus cases does not exceed 700 (some sources cite even lower numbers). On the other hand, there is no vaccine for the Nipah virus (NiV), and practically no other treatment for patients. For this reason, health authorities in Asian countries react nervously even to single new cases. Recently, in response to two new cases, health services in several Asian countries have tightened airport controls.
We all remember the many conflicting reports that reached us in the early days of the COVID-19 pandemic caused by the SARS-CoV-2 virus, so information about the zoonotic origin of the Nipah virus and the severe encephalitis or pneumonia it causes has understandably sparked concern in Europe. On the other hand, a statement issued a few days ago by the European Centre for Disease Prevention and Control (ECDC) is rather reassuring. It states, among other things, that "the risk of infection for people from Europe traveling to or living in that region is assessed as very low".
So, should we be afraid or not? Are international institutions (e.g., WHO, ECDC) planning to settle for heightened airport checks and reassuring statements, or are they doing more? Can the virus escape this meager control, and how? What are scientists doing?
It must be clearly stated that the Nipah virus is recognized as a threat to global health security. Although human infections are currently limited to South and Southeast Asia, the World Health Organization (WHO) classifies it as a priority pathogen due to its wide range of hosts (fruit bats), potential for human-to-human transmission, and lack of approved vaccines or treatments, raising concerns about future epidemics. The virus has a high Case Fatality Rate (CFR), which measures the percentage of deaths among confirmed cases (for the NiV-B strain, CFR is 100%). Worse still, comprehensive studies on the Nipah virus lifecycle, transmission, and pathogenesis are still in early stages. One limiting factor is that it belongs to BSL-4 pathogens, the highest-risk group, like the Ebola hemorrhagic fever virus. Research on these can only occur in maximum-security BSL-4 labs, which are few worldwide and located in specialized centers. Nevertheless, significant progress has recently been made in understanding the virus's mechanism.
Paradoxically, the high CFR and limited human-to-human transmission may reduce the likelihood of a Nipah pandemic, as highly lethal viruses typically do not spread widely. But (there's always a but!): due to the error-prone replication mechanism of
NiV, a new mutated strain with lower lethality and higher infectivity cannot be ruled out. Thus, vigilance is crucial, as NiV could evolve into a virulent strain capable of efficient human-to-human spread, leading to a global health crisis.
Recent scientific research focuses on identifying viral genes and characterizing their proteins. NiV has a single-stranded RNA genome of about 18,200 nucleotides. The envelope proteins F and G control the virus's attachment to and entry into host lung epithelial cells and neurons. The partners for viral protein G are host cell surface proteins ephrin-B2 (EFNB2) and ephrin-B3 (EFNB3), found on epithelial cells and neurons, respectively.
It's worth noting that a barrier to developing NiV vaccines is the low number of cases, resulting in insufficient sample sizes for traditional phase III clinical trials. Thus, advanced bioinformatics tools are gaining importance in molecular virology and next-generation antiviral vaccine research. According to proponents of this new approach (e.g., Debora Marks et al., Nature 2023), effective pandemic preparedness is possible by predicting mutations that evade the host immune response. Viral pandemics have taught scientists and doctors that these diseases involve complex interactions between viral detection by the host immune system and viral evasion, often leading to antigenic protein evolution (a molecular arms race between virus and host). Mutations enabling immune evasion affect reinfection rates and vaccine duration. Predicting such variants in advance is key to optimal vaccines and drugs.
In other words: until now, even flu vaccines lagged a step behind the virus and its mutants. Using innovative mutation prediction in viral genomes, we can stay half a step ahead. These methods may prepare us for global threats from Nipah and other dangerous pathogens.
