From: Seizures and epilepsy secondary to viral infection in the central nervous system
Genus or family [6] | Virus and type of nucleic acid [6] | Route of transmission | Geographical distribution | Peak seasonal incidence | Laboratory testing |
---|---|---|---|---|---|
Flaviviridae | Japanese encephalitis virus (RNA virus) | Transmitted by genus Culex | India, China, Japan, South East Asia, Eastern Mediterranean region, Papua New Guinea, Australia [1] | Summer and early fall | CSF PCR; serum and CSF IgM (elevated in CSF in the first few days, sensitivity and specificity > 90%) and IgG [7] |
Dengue virus (RNA virus) | Transmitted by genus Aedes | India, China, Japan, South East Asia, Eastern Mediterranean region, Papua New Guinea, Australia [8] | Summer and early fall | PCR or antigen testing of respiratory secretions [8] | |
Zika virus (RNA virus) | Transmitted by genus Aedes; mother-to-child transmission through placenta; sexual transmission [9] | Africa, South America, Southeast Asia (Pacific region) | More frequent in summer and early fall (in the temperate zone); no seasonality (in the tropics) | Serum or urine PCR; serum or CSF IgM [9] | |
Herpesviridae | Herpes simplex virus (DNA virus) | Sexual; contact transmission | Worldwide | No seasonality | CSF PCR [8]; CSF IgG (if neurological manifestations last more than a week) [10, 11] |
Cytomegalovirus (DNA virus) | Mother-to-child transmission through placenta, labour, breast milk; sexual transmission; blood transfusion | Worldwide | No seasonality | Serum and CSF PCR; serum and CSF IgM or IgG [8] | |
Varicella zoster virus (DNA virus) | Close contact and droplet transmission [12] | Worldwide | All seasons, more frequently in late winter and spring [12] | CSF PCR | |
Epstein Barr virus (DNA virus) | Saliva or droplets transmission [13] | Worldwide | No seasonality | CSF PCR; serum viral capsid antigen, IgM [14] | |
Retroviridae | Human immunodeficiency virus (RNA virus) | Sexual transmission; direct contact; blood or blood products | Sub-Saharan Africa, Central Asia, Latin, America, Eastern Europe [1] | No seasonality | PCR or serum IgG |
Paramyxoviridae | Measles virus (RNA virus) | Droplet transmission; direct contact with nasal or throat secretions [15] | Worldwide [8] | All seasons, more frequently in late spring | Serum IgM; CSF PCR; nasopharyngeal, throat or urine PCR [8] |
Mumps virus (RNA virus) | Droplet transmission | Worldwide [8] | Winter and spring (in the temperate zone); no seasonality (in the tropics) [16] | Serum IgM; CSF PCR (high sensitivity); viral isolation from CSF, saliva, urine [8] | |
Nipah virus (RNA virus) | Droplet transmission; direct contact transmission (bats-to-human, pigs-to-human, human-to-human occasionally) [17] | Bangladesh, India, South-East Asia, Australia [8] | More frequent from January to May [18] | Serum and CSF IgM/IgG; CSF, serum and urine PCR [8] | |
Orthomyxoviridae | Influenza (RNA virus) | Droplet transmission; contact transmission | Worldwide distribution but encephalopathy most frequently reported in Japan and Australia [8] | Winter and spring | Nasopharyngeal swab, respiratory secretions PCR [19] |