ARBOVIRUS LABORATORY

 

A.      Virological surveillance and research activities

a.       Haemorrhagic fever:

  1. Molecular epidemiology study of Arboviruses circulating in southern Vietnam, during 1990 – 2005. Establishing the genotype map for Dengue and Japanese encephalitis viruses and determining the trend of epidemic transmission.
  2. Pathogenesis study of Dengue haemorrhagic fever (DHF): Studying the role of host factors (such as cellular immunity, humoral immunity, genetic gene), viral factors (genetic evolution, variation, recombinant gene, growth in the mosquito and mammalian cell cultures, variant morphology in electronic microscope) and vectorial factors (collaborated with medical entomology laboratory) in relation to clinical manifestation. Thus, finding the viral virulent marker and predictive indicator for severe cases.
  3. Applicable study of new technologies (such as molecular biology, immunology) for antigen detection using in precocious diagnosis of arbovirus infections and serving to diagnosis, treatment, surveillance, prevention and control.
  4. Studying the causes of dengue-suspected febrile diseases.
  5. Studying the human susceptible gene in relation with DHF severity.
  6. Studying the role of CD4 – CD8 cellular immunity in DHF severity.
  7. Study of cellular factors (such as CD3, CD14, CD16, CD19), humoral factors (cytokines), biological factors (growth in cell culture, neurovirulence in mice) and genetic factors (gene mutation) in relation with disease severity.
  8. Improving the MAC-ELISA test kit for using in diagnosis and active surveillance of DHF.
  9. Setting up the IgG-ELISA, AAC-ELISA, and Dot-blot ELISA for using in rapid DHF diagnosis at commune level.
  10. Evaluation of Plaque Reduction Neutralization Test (PRNT) using in DHF study and in investigation of dengue serotype transmission in nature.
  11. Achievement of all targets proposed for virological and serological surveillance of DHF in national programme of dengue control and participation of intervention measures studies for dengue vector control in the field.
  12. Laboratory-based active surveillance and investigation of HF caused by Dengue and Hantaviruses in human and animal.
  13. Serological and molecular biological surveillance of Hantaviruses in “Haemorrhagic fever with Renal syndrome and/or with Pulmonary syndrome”.
  14. Study of Hantavirus circulation in human and rodents.
  15. Support of technician network in provincial laboratories for diagnosis of Arbovirus and Hantavirus infections.  

b.      Encephalitis:

  1. Study of enhancement Japanese encephalitis antibody in dengue infections by PRNT.
  2. Isolation of new arboviruses from mosquitoes and determining their causative role in human acute encephalitis syndrome in southern Vietnam.
  3. Isolation of arboviruses from bats and determining their causative role in human and animal.
  4. Determining the main and auxiliary vectors of Japanese encephalitis transmission (collaboration with medical entomological laboratory).
  5. Application of diagnosis method for Nipahvirus encephalitis within the scope of emerging diseases investigation.
  6. Serological and virological surveillance of Nipahvirus in human and animals (such as pigs, bats).
  7. Production of MAC-ELISA test kits for diagnosis of DHF and Japanese encephalitis diseases.

B.      Applicable technologies

a.       Virology:

  • Viral isolation of Dengue, Japanese encephalitis and other arboviruses in C6/36, AP61, BHK-21 and Vero cell lines.
  • Viral isolation of Dengue and Japanese encephalitis virus in suckling mice.
  • RT-PCR detected Alphaviruses and Flaviviruses.
  • Nested-PCR for typing Dengue viruses.
  • Virus titration in cell culture.
  • Direct immunofluorescent test for identifying Flavivirus and Alphavirus groups.
  • Indirect immunofluorescent test for identifying Dengue, Japanese encephalitis, and Chikungunya, West Nile, Sindbis and Yellow Fever.
  • Sequencing of arboviruses.

b.      Serology:

  • Enzyme-linked immunosorbent assay = ELISA: MAC-ELISA detecting IgM antibody in the diagnosis of Flavivirus-group infection (such as Dengue Haemorrhagic Fever, Japanese Encephalitis), of Alphavirus-group (such as Chikungunya, Metri, Sindbis), of Bunjaweravirus-group (such as Hantavirus). GAC-ELISA detecting IgG antibody in the diagnosis of Dengue and Japanese encephalitis infections.
  • Haemagglutination-Inhibition test using in qualitive and quantitative detection of IgG antibody for Dengue and Japanese encephalitis infection.
  • Haemagglutination test using in the antigen titration of Flavivirus-group (such as Dengue-1, -2, -3, -4 and Japanese encephalitis viruses) and Alphavirus-group (such as Chikungunya, Metri viruses).
  • Plaque Reduction Neutralization Test for the immune response investigation of patients infected by Dengue or Japanese encephalitis viruses.