Seroprevalance of dengue viral infections and serotype specific t cell responses in healthy individuals in Colombo, Sri lanka

Chandima Jeewandara; GN Malavige; Vathsala Jayasuriya; M.H.J.D. Ariyaratne; Mallika Peellawate; Graham S. Ogg

Authors

Chandima Jeewandara Faculty of Medical Sciences, University of Sri Jayawardanapura
GN Malavige Faculty of Medical Sciences, University of Sri Jayawardanapura
Vathsala Jayasuriya Faculty of Medical Sciences, University of Sri Jayawardanapura
M.H.J.D. Ariyaratne Faculty of Medical Sciences, University of Sri Jayawardanapura
Mallika Peellawate Faculty of Medical Sciences, University of Sri Jayawardanapura
Graham S. Ogg MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, Oxford

Abstract

Objective: Although dengue viral infections cause dengue haemorrhagic fever and fatalities in some individuals, it is a mild /asymptomatic infection in the majority of infected individuals. Therefore, we set out to determine silent dengue transmission in the community.

Methods: 236 healthy individuals aged 5-80 years recruited from community to test the presence of anti-dengue virus(DV)antibodies. Ex vivo and cultured ELISpot assays for serotype specific (SS)DV peptides, DEN3 NS3 and non-dengue viral peptides were done in 47/263 individuals. Cultured ELISpots for SS responses done in 3 individuals < 20 years, in 20 for 20-40years age and in 24 aged >40years.

Results: The seropositivity rates for DV-specific antibodies were 40%,62.5%,100% at 10,20,40 years of age respectively. A significant(p=0.001) and positive correlation observed with age and DV- seropositivity (Spearman r =0.8365,95%CI 0.55-0.95). SS T cell responses detected in all seropositive individuals(n=44) but absent in all dengue seronegative (n=3) individuals.

SS responses seen in only 1 person of the <20 age group who responded to SS peptides of DEN-2. 3/20(25%), 6/20(40%), 3/20(25%) and 5/20(30%) of individuals between 2-40 years responded to at least one SS peptide of DEN-1, DEN-2, DEN3 and DEN-4 peptides respectively. 12/24(50%), 5/24(33%), 12/24(50%) and 6/24(25%) of individuals aged >40 years responded to at least one SS peptide of DEN-1, DEN-2, DEN-3 and DEN-4 peptides respectively.

Conclusions: Seropositivity rates to the DV significantly rises with age, almost 100% at 40 years of age. The SS T cell responses to DEN-1 and DEN-3 SS peptides were more frequent aged >40 years.