Usage of saliva for non-invasive dengue diagnosis

Abstract

Background: Dengue fever (DF) is a mosquito-borne viral disease. It occurs in over 100 countries and the most significant epidemics occur in Southeast Asia, the Americas and the Western Pacific. All the four serotypes can cause DF and the more severe and fatal Dengue Haemorrhagic Fever (DHF). The necessity of a venous blood collection in all dengue diagnostic assays can hinder early detection of dengue cases and thus could delay vector control efforts. The Environmental Health Institute (EHI) has developed a saliva based test using antigen capture anti-DENV IgA (ACA) enzyme-linked immunosorbent assay (ELISA) technique. We believe saliva testing can encourage patients to be more receptive towards dengue diagnosis. In our continuing effort to improve DENV diagnostics, we have also optimised our RT-PCR protocol to be able to detect and serotype DENV 1-4 in clinical saliva samples. Methods: Saliva (and corresponding blood samples) from febrile patients were collected using buccal swabs and kept in Universal Transport Media (UTM). RT-PCR was done on both saliva and serum samples and results from dengue confirmed patients were compared. Virus isolation was also performed using the saliva samples. Results: We are able to detect and identify the different DENV serotypes in the saliva samples, and saliva serotypes correlated with DENV serotypes in the corresponding serum samples. Virus isolation was also successful in 80% of the samples. Conclusion: Saliva can also potentially replace blood as the biospecimen of choice for dengue diagnosis without compromising any downstream virus work.