Relapsed and late-onset Nipah encephalitis.
An outbreak of infection with the Nipah virus, a novel paramyxovirus, occurred among pig farmers between September 1998 and June 1999 in Malaysia, involving 265 patients with 105 fatalities. This is a follow-up study 24 months after the outbreak. Twelve survivors (7.5%) of acute encephalitis had recurrent neurological disease (relapsed encephalitis). Of those who initially had acute nonencephalitic or asymptomatic infection, 10 patients (3.4%) had late-onset encephalitis. The mean interval between the first neurological episode and the time of initial infection was 8.4 months. Three patients had a second neurological episode. The onset of the relapsed or late-onset encephalitis was usually acute. Common clinical features were fever, headache, seizures, and focal neurological signs. Four of the 22 relapsed and late-onset encephalitis patients (18%) died. Magnetic resonance imaging typically showed patchy areas of confluent cortical lesions. Serial single-photon emission computed tomography showed the evolution of focal hyperperfusion to hypoperfusion in the corresponding areas. Necropsy of 2 patients showed changes of focal encephalitis with positive immunolocalization for Nipah virus antigens but no evidence of perivenous demyelination. We concluded that a unique relapsing and remitting encephalitis or late-onset encephalitis may result as a complication of persistent Nipah virus infection in the central nervous system.
Department of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. tlip@pl.jaring.my
Chong Tin
CT
Tan
Khean Jin
KJ
Goh
Kum Thong
KT
Wong
Sazilah Ahmad
SA
Sarji
Kaw Bing
KB
Chua
Nee Kong
NK
Chew
Paramsothy
P
Murugasu
Yet Lin
YL
Loh
Heng Thay
HT
Chong
Kay Sin
KS
Tan
Tarmizi
T
Thayaparan
Shalini
S
Kumar
Mohd Rani
MR
Jusoh
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology; D002648:Child; D004569:Electroencephalography; D018792:Encephalitis, Viral / Q000473:pathology / Q000503:physiopathology* / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008296:Malaysia; D008297:Male; D008875:Middle Aged; D018184:Paramyxoviridae Infections / Q000473:pathology / Q000503:physiopathology* / Q000517:prevention & control; D018098:Paramyxovirinae; D012008:Recurrence; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon