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Volume 21, Number 2—February 2015
CME ACTIVITY - Research

Infectious Causes of Encephalitis and Meningoencephalitis in Thailand, 2003–2005

Sonja J. Olsen1Comments to Author , Angela P. Campbell1, Krongkaew Supawat, Sahas Liamsuwan, Tawee Chotpitayasunondh, Somsak Laptikulthum, Akravudh Viriyavejakul, Tasanee Tantirittisak, Supoch Tunlayadechanont, Anannit Visudtibhan, Punnee Vasiknanonte, Supachai Janjindamai, Pairoj Boonluksiri, Kiatsak Rajborirug, Veerachai Watanaveeradej, Nino Khetsuriani, Scott F. Dowell, and Thailand Encephalitis Surveillance Team
Author affiliations: Thailand Ministry of Public Health–US CDC Collaboration, Nonthaburi, Thailand (S.J. Olsen, S.F. Dowell); Centers for Disease Control and Prevention, Atlanta, Georgia, USA (S.J. Olsen, A.P. Campbell, N. Khetsuriani, S.F. Dowell); Thailand Ministry of Health, Nonthaburi (K. Supawat); Queen Sirikit National Institute of Child Health, Bangkok (S. Liamsuwan, T. Chotpitayasunondh); Rajvithi Hospital, Bangkok (S. Laptikulthum); Prasat Neurological Institute of Thailand, Bangkok (A. Viriyavejakul, T. Tantirittisak); Ramathibodi Hospital, Bangkok (S. Tunlayadechanont, A. Visudtibhan); Prince Songkhla University Hospital, Hat Yai, Thailand (P. Vasiknanonte, S. Janjindamai); Hat Yai Hospital, Hat Yai (P. Boonluksiri, K. Rajborirug); Phramongkutklao Hospital, Bangkok (V. Watanaveeradej)

Main Article

Table 1

Classification strategy for etiology of encephalitis, Thailand, 2003–2005*

Agent Established cause of encephalitis Diagnostic category
Confirmed Probable Possible
Bacteria
Bartonella henselae Yes ≥4-fold rise serum Ab titer (IFA)
Haemophilus influenzae Rare CSF or blood culture positive
CSF latex agglutination positive
Mycobacterium tuberculosis Rare CSF culture positive
Mycoplasma pneumoniae Yes CSF PCR positive Serologic conversion (neg to pos) on serum Ab titer (EIA) OP PCR positive
Neisseria meningitidis Rare CSF or blood culture positive
CSF latex agglutination positive
Rickettsia spp. (e.g., Rickettsia conorii, Orientia tsutsugamushi) Yes >4-fold rise serum Ab titer
Streptococcus pneumoniae Rare CSF or blood culture positive; CSF latex agglutination positive
Treponema pallidum Yes CSF VDRL positive Blood specific treponemal Ab positive
Other Rare (organism dependent) CSF or blood culture positive; CSF 16S RNA PCR positive + sequence (organism dependent) CSF 16S RNA PCR positive + sequence (organism dependent) Blood culture positive (organism dependent)
Fungi
Cryptococcus spp. Yes (in immunocompromised patients) CSF culture positive; India ink positive; cryptococcal antigen positive
Parasites
Malaria parasites Yes Thick or thin smear positive in presence of malarial disease
Other parasites (e.g., Toxoplasma gondii) Yes (parasite dependent) Detection of parasites in CSF or brain
Viruses
Adenoviruses Yes (except for enteric HAdV 40, 41) CSF PCR positive (other than HAdV 40, 41) ≥4-fold rise serum Ab titer (EIA); OP PCR positive; CSF PCR positive for HAdV 40, 41
Chikungunya virus Rare IgM in CSF with CHIKV PRNT titer >1:10 in CSF or serum >4-fold rise in neutralizing Ab titers in serum
Cytomegalovirus
(Human herpesvirus 5) Yes (mostly in immunocompromised patients) CSF PCR positive
Dengue virus Rare DENV RNA in serum or CSF; DENV IgM in serum with a DENV PRNT90 titer >1:20 and a DENV PRNT90 to JEV PRNT90 titer ratio >1:4
Enteroviruses Yes CSF isolation in culture; CSF PCR positive 4-fold rise Ab titer
Epstein-Barr virus (human herpesvirus 4) Yes, dependent on clinical situation CSF PCR positive (predictive value in immunocompetent hosts is unclear)
Herpes simplex viruses 1 and 2 Yes CSF PCR positive CSF IgM present
Human herpesvirus 6 Yes CSF PCR positive
Human herpesvirus 7 Yes (in immunocompromised patients), not well established CSF PCR positive
HIV Yes Serology with Western blot positive
Influenza viruses Rare >4-fold rise serum Ab titer OP PCR positive
Japanese encephalitis virus Yes JEV IgM in CSF; JEV IgM in serum with a JEV PRNT90 titer >1:20 and a JEV PRNT90 to DENV PRNT90 titer ratio >1:4 JEV IgM in serum with a JEV PRNT90 titer >1:20 but a JEV PRNT90 to DENV PRNT90 titer ratio <1:4
Measles virus Yes CSF Ab positive >4-fold rise serum Ab titer if no recent vaccination
Mumps virus Yes CSF Ab positive >4-fold rise serum Ab titer if no recent vaccination
Nipah virus Yes CSF PCR positive; 4-fold rise serum Ab titer
PIV 1, 2, and 3 No (PIV1, 2) Yes (PIV3) >4-fold rise serum Ab titer (EIA); OP PCR positive
Rabies virus Yes >1 positive test:
CSF PCR positive; saliva PCR positive IgG detected in convalescent serum
Rubella virus Yes CSF Ab positive >4-fold rise serum Ab titer if no recent vaccination
Varicella-zoster virus (human herpesvirus 3) Yes CSF PCR positive
WNV Yes IgM in CSF; IgM in serum with a WNV PRNT titer >1:20 and >1:4-fold higher than JEV and DENV titer IgM in serum with a WNV PRNT title >1:20 but <1:4-fold higher than JEV and DENV titer

*Ab, antibody; CHIKV, chikungunya virus; CSF, cerebrospinal fluid; EIA, enzyme immunoassay; IFA, immunofluorescence assay; OP, oropharyngeal swab sample; PRNT90, 90% plaque reduction neutralization test; HAdV, human adenoviruses; DENV, dengue virus; JEV, Japanese encephalitis virus; PIV, parainfluenza virus; WNV, West Nile virus. Blank cells indicate not applicable.

Main Article

1These authors contributed equally to this article.

2Members are listed at the end of this article.

Page created: January 15, 2015
Page updated: January 15, 2015
Page reviewed: January 15, 2015
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
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