Volume 21, Number 2—February 2015
CME ACTIVITY - Research
Infectious Causes of Encephalitis and Meningoencephalitis in Thailand, 2003–2005
Sonja J. Olsen1
, 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
, 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
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.
1These authors contributed equally to this article.
2Members are listed at the end of this article.
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