Abstract:
The study group consisted of a total of 273 samples from clinically suspected DHF patients
whose samples were sent to the MRI between March and September 1995.Out of these,244
were acute samples and 29 were convalescent samples. These were grouped into the
following. Group 1-consisted of 29 paired sera clinically suspected of having DHF who had
a four fold rise in the HI antibody titer, where there were 5 primary dengue infections and
24 secondary dengue infections. The acute samples were collected between 1-8 days of
onset of illness and the convalescent samples were collected between 12-20 days of onset of
illness. Group 2- consisted of 111 single sera with a HI titer of = 1:2560 collected between
2-8 days of onset of illness. Group 3- consisted of 64 single serum samples with a HI titer of
1:20 and 1:1280 with the collection of blood samples between 2-9 days of onset of illness.
Group 4- consisted of 40 single sera with a HI titer of 1:20 and samples were collected
between 1-9 days of the onset of the disease. No laboratory based study has been carried out
using both HI and IgM MAC-ELISA tests in Sri Lanka. The serum samples were tested for
both HI and IgM antibody. A commercially available IgM MAC-ELISA test kit
(PanBio,Australia) was used. The appearance of IgM was seen in all 4 groups at a higher
precentage in the 5-8 day than the 0-4 day of the onset of illness ie. the figures for group
1,2,3 and 4,on the 0-4th day of illness respectively were 25 per cent,17 per cent,18.2 per
cent, and 12.5 per cent.On the 5-8th day of the illness it was 81.8 per cent,85.7 per cent,73.8
per cent and 20.8 per cent. This shows a similar response as with other studies done in
puerto rico and brazil. Further studies should be done to see the persistence of IgM in the Sri
Lankan population
