Abstract

OCAZIONEZ, Raquel; CORTES, Fabián  and  VILLAR, Luis Angel. Surveillance of the Dengue based on the laboratory: differences in the number of cases and virus isolated according to the gathering of the serum and serologic tests. Colomb. Med. [online]. 2005, vol.36, n.2, pp.65-72. ISSN 1657-9534.

BACKGRAUND: Dengue control measures depend on the laboratory-based surveillance data. In this study was investigated the differences in dengue cases and viruses isolated in according with surveillance strategy. STUDY DESIGN AND METHODS: Two surveillance strategies were analyzed in this study. First (Local Surveillance System): single serum sample (acute or convalescent) was collected from 337 dengue suspected cases and then kept at 4^oC. IgM antibodies were detected using UMELISA DENGUE kit (IPK, Cuba), and serotypes identification was performed by viral isolation attempts in C6/36. Second: paired serum sample were collected from 318 dengue suspected cases and then kept at -70ºC. IgM antibodies were detected using MAC-ELISA test and virus isolation as above. Some paired sera analyzed by MAC-ELISA were processed by “Dengue IgM-capture ELISA” kit (PANBIO) and “IgM*ELISA anti-dengue” (IPK, Cuba). RESULTS: More IgM+ dengue cases were detected by the first than second strategy using acute or convalescent serum: 61.1 vs 22% (p<0.001) y 86.8 vs 49.3% (p<0.001), respectively. Dengue diagnosis by MAC-ELISA was concordant in 85% (K=0.29) respect to UM-ELISA, but 100% (K=1) and 90.4% (K=0.84) respect to “IgM ELISA anti-dengue” and “Dengue IgM-capture ELISA” kits. Differences in dengue cases detected by the second strategy were found when serological result with single acute or paired samples was compared: 70 (22%) vs 155 (48.7%) (p<0.001). Dengue virus was isolated more frequently from sera kept at -70ºC than those kept at 4ºC: 17.8% vs. 4.7% (p<0.001). All virus serotypes were isolated. The UMELISA DENGUE test specificity and relationship between impact dengue surveillance and implemented strategy are analyzed. CONCLUSIONS: The specificity of UMELISA DENGUE test require to be evaluated by the high frequency of dengue in suspected cases. Serum paired analyzes in dengue surveillance is necessary to obtain reliable information.

Keywords : Dengue; IgM-capture ELISA; Viral isolation; Dengue virus serotypes.

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