Evaluation of dengue blot test

Dengue blot test is a dot enzyme immuno-assay which detects the antibodies to dengue virus of all tyes (1 to 4). The result of the test can be obtained after three hours.In the management od dengue haemorrhagic fever confirmation of diagnosis should be made at early stage.This requires a test which is highly specific, highly sensitive and quick.To determine the usefulness of dengue blot test in diagnosing dengue haemorrhagic fever, this study was carried out in 319 patients who were clinically diagnosed as dengue haemorrhagic fever at Yangon Children Hospital.They were tested for both blot test and standard test of haemagglutination inhibition (HI).Blot test was positive in 304 patients out of which only one is negative for HI test (True positive 303 false positive 1).Out of 15 patients who were negative for blot test 10 were positive for HI test (True negative 5, false negative 10).This test was found to be highly sensitive (sensitivity 96

), and specific (specificity 83

).Positive predictive valve was 99.6

but negative predictive value was only 33.3

.

A study on thiamine nutritional status of Khayan Township

As staple food of Myanmar is rice, there is a risk to develop thiamine deficiency. So a study was conducted in Khayan township to assess its thiamine nutritional status. Transketolase enzyme activity stimulation test of 59 pregnant women and 26 lactating mothers were studied and 12.9 per cent of them were found to be in deficient state. Thiamine concentration of breast milk samples collected from 31 lactating mothers was also measured; the mean value was 6.7 + or - 4.3 mcg/100ml. Rice samples were collected from conventinal type rice mills, Huller type rice mills and residences of Paukone village, and their thiamine content were 59.7 + or - 23.6 mcg/100gm (n=5), 66.8 + or - 22.7 mcg/100gm (n=20) and 73.97 + or - 41.2 mcg/100gm (n=26) respectively. Boiled rice samples were also collected from Paukone village and the mean thiamine content was 10.74 + or - 8.73 mcg/100gm (n=33). Thus it seems that thiamine nutritional status of Khayan is not in a satisfactory state.

Genotype determination of three dengue type 2 virus strains from Myanmar by sequencing E/NSI gene junction.

Genotype of three dengue-2 virus strains from Myanmar was determined as genotype II by sequencing 240 nucleotide long fragment across the E/NS1 gene junction by the primer extension dideoxy chain termination method, applying direct sequencing of the PCR product. These strains were isolated from a dengue shock syndrome (DSS) patient and two patients with dengue hemorrhagic fever (DHF) grade 1, in Yangon (Rangoon), Myanmar (Burma), in 1987. Sequence homology of all three strains were highest (96%) to New Guinea C strain (genotype II), lesser homology (93%) to Jamaican 1409 strain (genotype III), and the least homology (91%) to PR 159/S1 strain (genotype I). Two DHF strains revealed only 2 nucleotide and 3 nucleotide differences compared with DSS strain, all at the 3rd position of the codons which resulted in silent mutations.

Serodiagnosis of using rondelles

The feasibility of rondelles (filter paper discs) as transport media of blood for serodiagnosis by Haemagglutination - inhibiton test of recent dengue infection is determined. Principles underlying the designs of the study are discussed. Blood may be collected on the rondelle by simple saturation from a finger prick. The convalescent specimen of blood should be taken ten days after collection of the acute specimen and both specimens should reach the laboratory within six days. Laboratory investigation should then be undertaken in another seven days as the antidengue antibodies are stable up to 23 days in blood collected on the rondelle. The blood soaked rondelles may be stored at room temperature (23C to 27C) or at 4Cin sealed plastic envelopes before sending to the laboratory. The conclusionsmade are supported by statistical analysis of the results.