Trends in the patterns of IgM and IgG antibodies in febrile persons with suspected dengue in Barbados 2006-2013

ABSTRACT

OBJECTIVES: To describe the seroprevalence of dengue antibodies in febrile suspected persons and investigated for dengue in this country. DESIGN AND METHODS: This was a retrospective population based study of all febrile children and adults with probable dengue from 2006 to 2013. Persons with probable dengue were investigated for dengue IgM and IgG antibodies in the blood sample drawn between days 3 to 5 of their illness. RESULTS: Among the 8296 cases that were tested for IgM antibodies, 2605 (36.6%) cases tested positive. Of the 7227 suspected cases who were tested for IgG, 5473 (75.7%) were positive. During the study years, between 80% and 90% of persons older than 20 years had a positive IgG antibody. Among the persons younger than five years (excluding the first year), between 10% and 20% had a positive IgM titre and a negative IgG titre, between 5 and10% had a positive IgM and IgG titre, 5% had a positive IgG titre and a negative IgM titre and between 45% and 65% had a negative IgM and a negative IgG titre. Between 37% and 59% had a serological evidence of past dengue in absence of any current dengue. CONCLUSIONS: The pattern of IgG antibodies seen in this study was comparable to those seen in the countries known to be hyperendemic for dengue. Based on the pattern of antibodies, the age of infection was likely to shift down to younger age groups with the likelihood of more severe forms of dengue in the future.