Acute encephalitis denotes brain inflammation most often arising from viral infection, with herpes simplex virus type 1 being a common cause in the UK, while autoimmune forms such as N-methyl D-aspartate receptor antibody encephalitis are increasingly identified [1]. It is recognized as a critical-care challenge in which diagnosis is frequently difficult and sometimes unconfirmed, and clear evidence-based therapies are lacking [2]. Outbreaks of acute encephalitis syndrome have also occurred, as seen in a 2019 India event with numerous child deaths and an unclear cause [3].
Disease overview
OtherAcute encephalitis excluding Japanese and West Nile encephalitis
急性脑炎（不含日本脑炎和西尼罗河脑炎）
Follow this disease Compare countries Evidence-backed information EN 1/6 applicable sections · ZH 1/6 applicable sections Updated Oct 23, 2026
Rabies is an acute encephalitis caused by rabies virus (RABV) infection, a member of the Rhabdoviridae family, causing about 59,000 human deaths per year and generally fatal once symptoms appear [1]. Encephalitis is brain inflammation most commonly due to viral infection such as herpes simplex virus type 1, presenting with altered consciousness, fever, seizures, or focal deficits [2]. Nipah virus is a zoonotic paramyxovirus causing acute encephalitis with high mortality, first recognized in 1999 in Malaysia and Singapore [3]. Acute encephalitis remains a critical care challenge with difficult diagnosis and unclear evidence-based therapies . An outbreak of acute encephalitis syndrome in Bihar, India in 2019 caused over 150 child deaths, mainly from hypoglycemia, with unclear cause .
Read the full clinical and epidemiological profile 2
- 1 Ellul M et al. Acute encephalitis - diagnosis and management. Clin Med (Lond). 2018 Mar. PMID: 29626021. doi: 10.7861/clinmedicine.18-2-155. PubMed: https://pubmed.ncbi.nlm.nih.gov/29626021/
- 2 Simon DW et al. Acute encephalitis. Crit Care Clin. 2013 Apr. PMID: 23537675. doi: 10.1016/j.ccc.2013.01.001. PubMed: https://pubmed.ncbi.nlm.nih.gov/23537675/
- 3 Wikipedia contributors. 2019 Bihar encephalitis outbreak [Internet]. Wikipedia. cited 12 Aug 2026. Available from: https://en.wikipedia.org/wiki/2019_Bihar_encephalitis_outbreak
- 4 Liu C et al. Epidemiology of Rabies and Current US Vaccine Guidelines. R I Med J (2013). 2020 Aug 3. PMID: 32752569. PubMed: https://pubmed.ncbi.nlm.nih.gov/32752569/
- 5 Kitsutani P et al. [Nipah virus infections]. Nihon Rinsho. 2005 Dec. PMID: 16363687. PubMed: https://pubmed.ncbi.nlm.nih.gov/16363687/
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