Serological and molecular diagnosis of measles using oral fluid samples
Abstract number: P776
Hutse V., Van Hecke K., De Bruyn R., Samu O., Lernout T., Muyembe J.J., Brochier B.
Objectives: Measles Virus (MV) is responsible for a very contagious disease characterised by high fever, coryza, cough, conjunctivitis followed by the appearance of a maculopapular rash. Despite the development of a combined vaccine (Measles-Mumps-Rubella), measles remains a major cause of mortality in developing countries and a cause of continuous outbreaks in more industrialised countries. Currently measles is diagnosed by traditional serological and molecular assays on serum and nasopharyngeal secretions.
The introduction of oral fluid as an alternative medium to serum would open many perspectives. In advantage to venepuncture, the collection of oral fluid is less invasive, less painful, less expensive (i.e. no trained personal required) and safer (prevention of needle stick injuries). Since measles appears mostly in children a non invasive sample collection like oral fluid would be an enormous asset to determine measles RNA and antibodies as quick as possible in case of/or to avoid epidemic measles outbreaks.
Methods: In this study seventy-three measles positive and fifty measles negative tripled samples (serum, oral fluid and nasopharyngeal secretions) were analysed. Samples were collected in the Democratic Republic of Congo (Kinshasa) by the National Measles Laboratory. In addition 22/50 negative samples came from volunteers of the Scientific Institute of Public Health, Belgium (IPH). Oral fluid samples were collected using an Oracol collection device (Malvern Medical Developments) and were controlled for quality and quantity by an IgG quantification assay.
The detection of measles antibodies was performed by commercialised ELISAs. An in-house nested RT-PCR has been developed for the detection of measles RNA.
Results: The anti-measles IgM ELISA (MicroImmune) on oral fluid has been validated against the IgM ELISA (Dade Behring) on serum (=golden standard) and resulted in a sensitivity and specificity of respectively 93.1% and 100%. The validation of a molecular nested RT-PCR on oral fluid was performed against the standard assay on nasopharyngeal secretions and gave a sensitivity and specificity of 100%.
Conclusion: The obtained results confirm that both serological and molecular oral fluid assays are suitable for routine use.
The use of oral fluid samples may also promote the participation rate of patients, GP's and paediatricians in the Belgium measles surveillance system and other epidemiological studies in the framework of WHO elimination programme.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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