PRELIMINARY NOTIFICATIONS ON SOME CASES OF ACUTE ENCEPHALITIS AND ASEPTIC MENINGITIS IN SOUTHERN VIETNAM, 2003

 

Phan Van Tu, Nguyen Thi Thanh Thao, Nguyen Thanh Long,

Huynh Thi Kim Loan, Vu Thi Que Huong, Nguyen Thi Kim Tien

Pasteur Insrtitute of Ho Chi Minh City

 

Abstract

There were 690 specimens tested at Pasteur Institute of Ho Chi Minh City from 366 patients with acute encephalitis, aseptic meningitis or meningoencephalitis from April to October, 2003. The CSF and serum samples were tested for Japanese encephalitis (JE) by IgM-ELISA. The CSF and stool specimens were inoculated in cell cultures (Vero, GL37, RD and HEp-2) for Enterovirus isolation. The viral isolates were identified by neutralization test (Nt) in cell cultures. RT PCR was applied to differentiate untypable Enteroviruses and other enteric viruses. Enterovirus 71 (EV71) was confirmed by RT PCR, Nt and indirect immunofluorescence. In CSF, JE-specific IgM antibody was determined in 39 of 165 (23.6%) cases and Enteroviruses were isolated in 9 of 268 cases (3.3%). In stool specimens, Enteroviruses were isolated in 32 of 185 (17.3%) cases including 2 cases with EV71. In sera, IgM antibody against EV71 was found in 5 of 8 (62.5%) serum samples; 81 of 227 (35.7%) cases had JE-specific IgM antibody and 2 of 10 (20%) cases had IgM for Herpes simplex virus. Among 16 fatal cases, 1 case with JE-specific IgM was detected in CSF; 2 cases with IgM against EV 71 and 1 case with IgM against Herpes simplex virus were found in serum; 2 cases had Enteroviruses isolated in stools. The notifications suggest the sporadic cases of acute encephalopathy in very young children with gastrointestinal disturbances and high case-fatality rate in Southern Vietnam. There were many different viral infections but no predominant causative virus found in the cases. However, EV71 found in some cases indicates its circulation in the region that may lead on an outbreak of encephalitis in the future as it has occurred in some other countries. The vigilance on EV 71 should be emphasized and a further study on causative agents of encephalitis will be conducted.