Study on the production of measles antibody used for vaccine quality control

Background: With the help of Japan, the Center for Research and Production of vaccines and biologicals, Hanoi has received a WHO standard measles vaccine production technology, including techniques in the examination of vaccine quality. Therefore, it is needed to be initiative on production of measles antibody. Objective: Study on production of measles antibody in rabbits and selecting the appropriate antibody for production of high titre antibody, which meets the standard of vaccine quality control in Vietnam. Subject and methods: Using the measles antigen from Edmonston and AIK-C strains, which were provided by the Kitasato Institute, to produce measles antibody. Making immunoreaction in rabbits and determination of neutralization antibody titre. Results and Conclusion: Measles antigen of Edmonston Vero 7/P2 strain used in the production of measles antibody in rabbit created the highest antibody titre in comparison with AIK-C strain from vero cell and FL cell supplied by the Kitasato Institute of Japan. Antibody titre of Edmonston Vero 7/P2 strain reached up to 1/8192 and met the sera standard required for measles vaccine quality control, it is similar to the measles sera to be produced from the Kitasato Institute.

Epidemiology of rotavirus diarrhea in the National Pediatric Hospital

Background: Rotavirus type A is the most common cause of acute gastrointestinal inflammatory in children under 5 years old, especially in age groups 6 and 36 months. Some rotavirus strains are common; seen recently in Vietnam are G1, G2, G3, G4 and G9, P4, P6 and P8. Objective: Surveillance of epidemiological characteristics of rotavirus induced diarrhea in the National Pediatric Hospital from September, 2007 to March, 2008. Subject and methods: Collection of 322 stool specimens of pediatric patients with acute diarrhea (including 213 specimens from male, 109 specimens from female), who were treated in the National Pediatric Hospital. All of these specimens were determined for causes of rotavirus with the enzyme immunoassay (EIA). Results and Conclusion: Among these 322 stool specimens, there were 195 rotavirus positive specimens, accounted for 60.56%. The rate of monthly distribution of rotavirus diarrhea from September, 2007 to March, 2008 were 76%, 56%, 62%, 61%, 64%, 56% and 44%, respectively. Number of rotavirus positive cases in male and female was 56 (26.29%) and 79 (72.48%), respectively. The rate of rotavirus positive children compared to total number of specimens with the age 0-3 months, 3-6 months, 6-12 months, 12-24 months, 24-36 months and over 36 months was 7.69%, 15.9%, 41.54%, 32.82%, 1.54% and 0.51%, respectively. The results of type identification indicated that phenotypes of 37 among 40 specimens were identified (92.5%) in which there were 5 specimens of G1P8 (12.5%), 20 specimens of G3P8 (50%), 1 specimen of G9P8 (2.5%), 2 specimens of G1Pmixed (5%), 9 specimens of G3Pmixed (22.5%), 1 specimen of G unidentified-type P8 (2.5%) and 2 specimens of G3 P unidentified-type (5%).

Epidemiology of ROTA virus diarrhea in Ho Chi Minh city from 12/2006-11/2007

Background: Acute gastroenterophathy usually caused by the Rota virus for children under 5 years old. Objectives: To present various types of data on epidemiology of ROTA virus diarrhea in Ho Chi Minh city from 12/2006-11/2007. Material and method: The data were collected from 500 stool specimens of diarrhea diagnosed chilren hosptalised at Thuy Dien Pediatric hospital 1, Ho Chi Minh city from December/2006 to November /2007. Results:There were 322 rotavirus-positive specimens, representing 64.4%. The proportions of monthly distribution of cases with diarrhea due to rotavirus were 90.1%, 54.39%, 85.37%, 74.51%, 72.92%, 41.67%, 26.67%, 58.33%, 79.31%, 52.63%, 69.05% and 57.78%, respectively. The numbers of rotavirus-positive cases in male and female were 216 (65.26%) and 106 (62.72%), respectively. The proportions of Rota virus positive children compared to total number of diarrheal cases with age 0-3, 3-6, 6-12, 12-24, 24-36 and over 36 months were 2.80%, 7.76%, 40.06%, 40.68%, 5.28% and 3.42%, respectively.\r\n', u'The results of typing identification indicated that the phenotypes of 98 among 100 specimens were identified (98%) in which there were sixty-one specimens of G1P8 (61%), one specimen of G2P8 (1%), fourteen specimens of G3P8 (14%), four of specimens of G4P8 (4%), eighteen specimens of GmixedP8 (18%). There were only two specimens of GnontypeableP8 (2%). Conclusion: Further studies should be carried out to clear this issue.\r\n', u'

Sequencing VP4, VP7, NSP1, NSP4 genes of human rotavirus strain G1P8

Background: Rotavirus is the main cause of acute viral gastroenteritis in children under 5 years old. The virus leads to over 600000 children deaths a year in the world, 80% of which occur in the developing countries. In Viet Nam, 50%-70% the children\u2019s hospitalizations for acute diarrhea were resulted from rotavirus infection. Objective: To sequence nucleotides and amino acids of VP4, VP7, NSP1, and NSP4 genes of 5 passages of human rotavirus strain G1P8. Materials and method: A study was conducted in rotavirus sample of 5 passages of human rotavirus strain G1P8: B17A3; B17.3; B17.3 pp32vero15; B17.3 pp36TKP2; B17.3 pp43.7vero in Centre for Disease Control and Prevention, Atlanta, United State. Methods: using NucliSen Kit for detection of ARN; RT-PCR; sequencing genes by ABI 3100 machine. Results and Conclusion: Sequencing nucleotides and amino acids of VP4, VP7, NSP1, and NSP4 genes of 5 passages of human rotavirus strain G1P8 showed that: the number of nucleotide mutations ofVP4, VP7, NSP4 genes occurring among the passages were 3 (at nucleotit 175, 419, 790), 1 (at nucleotit 644), 3 (at nucleotit 134, 254, 482), respectively. All these mutations resulted in changes in amino acid composition. No mutation was found in NSP1 gene.

Study of sequencing of VP4, VP7, NSP1, NSP4 genes of human rotavirus strain G4P6 (2001019203)

Background: Rotavirus is the main cause of acute viral gastroenteritis in children under 5 years old. In Viet Nam, about 50-70% hospitalized children with acute diarrhea caused by rotavirus. This indicated the importance of vaccination against diarrhea in Vietnam and researching on creating safe diarrhea vaccine for infants was a imperative. To achieve a good result of the research, it\u2019s necessary to understand the genetic characteristics of rotavirus.Objectives: To determine sequencing of VP4, VP7, NSP1, NSP4 genes of human rotavirus strain G4P6. Subjects and method: The research was performed on rotavirus samples (203pp16TK; 203pp27TK; 203pp30vero; 203pp37vero; 203pp38vero lot11; 203pp38TK lot12) by using ARN separation and RT-PCR methods. Results and Conclusion: We presented the results of sequencing of VP4, VP7, NSP1, NSP4 genes in some passages of human rotavirus strain G4P6 including their deduced amino acid sequence. The nucleotide mutants of VP7, NSP4 genes of passages are 2, 1 respectively. All the mutants result in amino acid changes. There was no mutation on VP4, NSP1 genes. The result confirmed that all passages of human rotavirus strain G4P6 had no contamination. They had similar degree respectively 89-93%, 85-97%, 81-93%, 92-95% with strains in the world.