453 cases of acute encephalitis syndrome were studied in the year 2002 at the National Institute of Pediatrics and 21 provinces of North Vietnam. Using Aedes albopictus clone C6/36, from CSF, 6 strains of Japanese encephalitis virus were isolated. By ELISA – Sandwich technique and indirect immunofluorescent assay, 4 virus strains were determined, including 4 strains of JE virus and 2 unknown viruses. 43.26% of cases of acute encephalitis syndrome were caused by JE virus. JE incidence in children of 1-4 years old reduced from 37.62% in 1989-1995 year period to 11.22% in 2002, due to the intensive immunization for children 1-5 years old.
Encephalitis, Japanese ; Encephalitis ; Diseases ; epidemiology

Background: Viet Nam is located in the epidemiological region of Japanese Encephalitis (JE). JE vaccine manufactured in Viet Nam has been used in the national vaccination program since 2003, but there has been no scientific study on the effectiveness of this program in Ha Nam province. Objectives: To investigate the epidemiology of JE and effectiveness of vaccinations in Ha Nam province from 2001-2006. Subjects and method: All residents in Ha Nam province, with the key focus group being JE cases. The retrospective and prospective epidemiological descriptive method was used. Results: The records of 148 cases of JE were collected. Among them, 42.5% (63 cases) were confirmed as JE by MAC-ELISA. The incidence and mortality rate were 1.29/100,000 and 0.12/100,000, respectively. Confirmed JE cases were found annually in all districts of Ha Nam province. However, it has been in decline, especially since the vaccination program was implemented for 1-5 year old children. The disease occurred in the summer with the peak in May and June (80.9% of total cases). Most of the cases were children under 15 years old (98.4%). The highest incidence rate was 6.4/100,000; 5.5/100,000 and 5.3/100,000 in the children aged 5-9, 1-4 and under 1 year old, respectively. Conclusion: The vaccination program appeared effective in reducing the mortality and morbidity of JE among children in Ha Nam province.
Japanese Encephalitis ; epidemiology

By MAC-ELISA technique, Japanese encephalitis infection incidence was determined in HaTay as high in summer months of May, June, July in consisting with that of epidemic season in North VietNam. In Tay Nguyen (Central Highland), the incidence of Japanese encephalitis was low in pig’s population, dispersing in all the year round, similarly as the epidemic cases identified in 1998-2002 year period. By UCNKHC (?) Japanese high level of encephalitis antibody in population was determined in all round 12 months. No relationship of Japanese encephalitis infection in pig’s population and Japanese encephalitis cases was identified
Encephalitis, Japanese ; Epidemiology ; Population

The analysis of evolutionary of JE virus in the North Vietnam was examined through 1,000 nucleotides of the envelope gene region encoded the E protein. 9 JE virus strains isolated from Vietnamese patients were sequenced and compared with previous published JE virus strains. The results showed that the Vietnamese strains isolated from human brain between 1986 and 1989 clustered in genotype 3. The strains isolated from mosquitoes and pigs between 2001 and 2002 clustered in genotype 1. The emerging JE virus genotype 1 in the North Vietnam among isolates from mosquitoes and pigs in the last few years was recorded for the first time. But JE virus genotype 1 was not detected among isolates from Vietnamese JE patients so far
Encephalitis, Japanese ; epidemiology ; Viruses

Result of the retrospective survey in 720 patients of Japanese encephalitis (JE) during 1990-2000 in Hai Phong Children's Hospital was showed that: age group from 5 to 9 was 51.5%, under 5 ages 29.9% and from 10-15 ages was 19.6%. The age groups of under 5, 5-9 and 10-15 years old were 28.9%, 51.5% and 19.6%, respectively. The prevalence in the rural area was higher than these in urban area. The morbidity occurred mainly in May-June. 67.8% (99/146) were detected positive by using MAC-ELISA
Epidemiology ; Encephalitis, Japanese ; child

Morbidity and mortality from acute encephalitis in Vietnam have remained very high, especially in the Northern region. Except for Japanese Encephalitis (JE), the acute viral encephalitis (VE) was not studied as needed. Study was conducted in 374 hospitalized patients aged under 15 with diagnosis of VE in 2003-2004. The results showed that the male to female ratio was 2.3:1. The morbidity and mortality in all ages were not different, but the mortality rate was higher in group of under 10. More than 75% of morbidity occured from April to July.
Encephalitis ; Epidemiology ; Epidemiologic Research Design

China ; epidemiology ; Encephalitis, Japanese ; epidemiology ; Laboratories ; standards

In the year 2002, a new arbovirus strain coded 02VN208 was isolated from cerebro- spinal fluid of patients with acute encephalitis syndrom by C6/36 mosquito cell lines. It’s a virus of 50nm spherical enveloped shape with ARN genetic materia. From a part of the extended sequence,specific primer pair was designed for determining the virus strains of the patients and the mosquitoes isolated by RT-PCR . 6 viral strains belonging to the same genotype of 02VN208 viral strain were confirmed. Results suggested that it’s a new arbovirus named Namdinh virus. Further study should be developed serologically and ultra morphologically
Encephalitis ; Viruses ; diagnosis ; Cerebrospinal Fluid ; epidemiology

Child ; China ; epidemiology ; Encephalitis Virus, Japanese ; Encephalitis, Viral ; epidemiology ; prevention & control ; Female ; Humans ; Japanese Encephalitis Vaccines ; immunology ; Male ; Vaccination

OBJECTIVETo detect the relations between incidence rate of the epidemical encephalitis B and related factors, to provide a simple, valid and practical new method for forecasting encephalitis B eipdemics.

METHODSConnection number between the incidence rate of encephalitis B and the historical forecast factors was computed, before ranking the first, second and the third principal factor, to remove the factor with the smallest value in the light of the connection number before comparing the newest value of forecast factors with the same kind of history while the most nearly value becoming the forecasting factor value and to establish a forecasting equation according to the factor value and the consistent degree of the incidence rate of encephalitis B at that time. Finally, to put into the new factor value to get this forecast value under this equation. Assuming that there are n' (n' >or= 2) forecast factors, this time forecast value can then be directly obtained from the average of these estimate values.

RESULTSUsing above forecast method to forecast the incidence rate of encephalitis B at certain place and year, the predicting value is very much close to the actual incidence rate. Difference between the predicting value forecasted by the above-mentioned method and the actual incidence rate is only 0.0264/100 000 with an accurate rate of 97.94%.

CONCLUSIONThis principal factor analysis forecast method based on connection number in forecasting the incidence rate of encephalitis B prevention is acceptable.

China ; epidemiology ; Encephalitis Virus, Japanese ; Encephalitis, Viral ; epidemiology ; virology ; Factor Analysis, Statistical ; Forecasting ; Humans ; Incidence