WHO has published a new technical brief on encephalitis , a serious, life-threatening neurological condition characterized by inflammation of the brain.
Encephalitis affects people across all age groups, has high mortality and often leads to significant long-term complications (sequelae) including hearing loss, seizures, limb weakness, and difficulties with vision, speech, language, memory and communication. Globally in 2021, encephalitis was the fourth leading cause of neurological health loss (i.e. disability-adjusted life years, DALYs) in children aged under 5 years and the 13th across all age groups.
Many different pathogens can cause encephalitis. Herpes simplex (HSV) is the most common cause of encephalitis globally. Autoimmune encephalitis, an inflammatory brain disorder driven by the immune system, is also increasingly recognized as a cause.
Some pathogens are spread by mosquitoes and ticks (vector-transmitted). Others can be prevented by vaccines, including influenza, varicella-zoster virus (VZV), rabies, poliomyelitis and encephalitis linked to measles, mumps and rubella (MMR). Some pathogens, like Japanese encephalitis virus (JEV), are both transmitted by vectors and can be prevented through vaccination.
Encephalitis is a growing global concern due to population density, intensive farming, climate change, vaccine hesitancy, and human-animal proximity, especially in under-resourced communities.
The technical brief, which forms part of the implementation of the broader Intersectoral global action plan on epilepsy and other neurological disorders (IGAP), draws attention to the lack of access to essential care, especially in low-and middle-income countries.
Worldwide, people living with encephalitis and associated disabilities continue to have difficulties accessing treatment and rehabilitation, and many also experience discrimination and human rights violations, further underscoring the need for urgent action.
The brief covers the diagnosis, treatment and care of encephalitis (i.e. care pathways; diagnosis; treatment; care, including social protection and welfare; rehabilitation; and an interdisciplinary workforce). It also addresses surveillance and prevention (i.e. vaccines and vector control), and research, advocacy and awareness.
"Encephalitis is a growing public health challenge, and by prioritizing it within global and national health agendas and strengthening collaboration, we can reduce its impact and save lives," said Dr Tarun Dua, Head of the Brain Health Unit, WHO. "These efforts will not only improve health outcomes and quality of life for those affected and their families but also result in stronger more resilient health systems."
This technical brief is based on evidence from a WHO-commissioned scoping review and discussions held at a WHO-convened meeting, Why encephalitis matters? with people with lived experience and carers, academics, researchers and service providers.
