Infectious epilepsies are epilepsies caused by infections that injure or inflame the brain. They form one of the six major aetiological categories recognised in modern epilepsy classification.
Infection can cause both acute seizures and later epilepsy
Seizures during meningitis, encephalitis, cerebral malaria or another acute CNS infection are usually classified as acute symptomatic seizures.
Epilepsy is diagnosed later when a person develops an enduring tendency to recurrent unprovoked seizures after the acute illness has resolved.
Why infection can become epileptogenic
Several mechanisms can contribute:
- direct neuronal injury;
- neuroinflammation;
- cerebral infarction or haemorrhage;
- gliosis and scarring;
- cortical malformation caused by congenital infection;
- calcification or persistent parasitic lesions;
- prolonged acute seizures or status epilepticus.
The global burden is uneven
WHO identifies CNS infection as an important preventable cause of epilepsy, particularly in low- and middle-income countries.
The relative importance of individual infections varies by geography, vaccination coverage, HIV prevalence, sanitation, malaria transmission, tuberculosis burden and access to treatment.
Bacterial meningitis
Bacterial meningitis can cause seizures during the acute illness and later epilepsy through cortical injury, infarction, abscess, hydrocephalus or other complications.
Meningitis and Later Epilepsy →
Encephalitis
Viral and immune-mediated encephalitis can produce both acute status epilepticus and later focal epilepsy.
Herpes simplex encephalitis is especially associated with temporal-lobe injury.
Neurocysticercosis
Neurocysticercosis is one of the most important preventable causes of epilepsy in endemic regions.
WHO estimates it may account for around 30% of epilepsy in some endemic settings.
Neurocysticercosis and Epilepsy →
Cerebral malaria
Cerebral malaria can cause acute seizures and later epilepsy, particularly after severe childhood disease.
Cerebral Malaria and Later Epilepsy →
CNS tuberculosis
Tuberculous meningitis and intracranial tuberculomas can cause seizures through inflammation, infarction and structural brain injury.
Tuberculosis of the CNS and Epilepsy →
HIV and opportunistic infection
In people with advanced HIV, seizures may result from opportunistic infections, tumours, metabolic disturbance, stroke, medication effects or direct effects of HIV on the nervous system.
HIV, Opportunistic CNS Infection and Epilepsy →
Congenital infections
Infections acquired during fetal development can disrupt cortical formation and produce structural brain abnormalities associated with later epilepsy.
Congenital Infections and Epilepsy →
Diagnosis
Assessment may involve EEG, MRI or CT, cerebrospinal-fluid analysis, microbiology, serology, PCR, immune testing and other pathogen-specific investigations.
The correct test depends on the suspected infection and whether the illness is acute or remote.
Treatment has two targets
Where infection is active, clinicians treat the underlying pathogen or inflammatory process as well as seizures.
Once a chronic epilepsy has developed after the infection has resolved, treatment follows ordinary epilepsy principles based on seizure type, structural lesion and individual circumstances.
Prevention matters
Vaccination, sanitation, malaria control, HIV treatment, tuberculosis prevention and rapid treatment of CNS infection can prevent part of the global epilepsy burden.
The central point
“Infectious epilepsy” does not mean epilepsy itself is contagious. It means an infection caused brain injury or inflammation that created an enduring tendency to seizures.
Sources
- WHO — Epilepsy
- WHO — Encephalitis: global threats, trends and public health implications — 2025
- WHO — Meningitis — 2025
Evidence checked: September 2026.