Meningitis Encephalitis: a Metagenomics-Based Etiology & Epidemiology Research

Inclusion Criteria: * Either meet the items of 1, 2 or 1, 3 1. The patient's age \>14 years old, acute or subacute onset (less than 3 months), (first onset, treatment with anti-infection drugs and/or immunotherapy ≤5 days); 2. The patient has the following symptoms: 1. Dysmnesia, 2. Seizures, 3. Mental disorders, 4. Abnormal behavior, 5. Unconsciousness or coma, 6. Dyskinesia or involuntary movement, 7. lalopathy or be reticent, 8. Dysphagia, sleep disorders, or autonomic nervous dysfunction, 9. Ataxia. 3. Patients with meningeal irritation sign, intracranial hypertension and other manifestations, satisfy at least 3 of the following symptoms: 1. Headache, 2. Fever, 3. Stiff neck, 4. Disturbance of consciousness, 5. Kernig sign or brudzinski sign was positive. Exclusion Criteria: * 1\. Patients with suspected metabolic encephalopathy and toxic encephalopathy have the above manifestations, * 2\. Patients with central nervous system tumor (primary or metastatic) have the above manifestations, * 3\. The patient with non-organic mental illness, * 4\. Patients who had undergone brain surgery within 6 months have the above symptoms after operation, * 5\. Patients with traumatic brain injury have the above manifestations, * 6\. Febrile convulsions caused by non-cerebral causes, * 7\. Patients with above manifestations due to other reasons such as cerebrovascular disease, genetic disease, etc; * 8\. Patients who refuse lumbar puncture or have contraindications to lumbar puncture; * 9\. Patients who withdraw informed consent.