Table 1 Inclusion and exclusion criteria

Inclusion criteria

• Aged from 18 to 80 years old

• Without clear diagnosis

• Without effective antimicrobial therapy

• The suspected meningitis/encephalitis patients should meet the ① or ② items as following:

① Suspected meningitis: Rapid onset fever (> 38.5 °C). with at least one of the three manifestations as following:

 (1) Neck stiffness

 (2) Alteration of consciousness

 (3) Other signs indicating meningitis, for example, meningeal irritation sign

② Suspected encephalitis: Altered consciousness because of unidentified reasons that persisted for longer than 24 h, including lethargy, irritability, or a change in personality, and have at least one of these manifestations:

 (1) Fever or history of fever (≥ 38 °C, oral temperature) during the presenting illness

 (2) Seizures not explained by a previously known seizure disorder

 (3) CSF pleocytosis (white blood cell count of more than 4 cells per μl)

 (4) Electroencephalographic (EEG) findings indicative of encephalitis

 (5) Abnormal results of neuroimaging (CT or MRI) suggestive of encephalitis

• Have an identifiable address and resided in the area during treatment

• Willing to participate in the treatment and follow-up and able to provide informed consent (if subject is illiterate, legal guardian sign or consent is required)

• Willing to comply follow-up procedures

Exclusion criteria (≥ 1 items)

• Lactation or pregnancy

• Fail to comply follow-up or treatment

• Researchers consider it is unsafe for participant

• No enough blood or CSF samples