Multivariate Analysis of Dengue in a Tertiary Care Hospital.

Malini, P (2013) Multivariate Analysis of Dengue in a Tertiary Care Hospital. Masters thesis, Coimbatore Medical College, Coimbatore.


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BACKGROUND : Dengue is a viral infection with potential fatal complications. It is considered as one of the worlds major emerging tropical diseases. More than 2.5 billion people are at risk of infection and more than 100 countries have endemic transmission. The emergence and reemergence of dengue is attributed to demographic and societal changes with increased movement of people from endemic areas and inadequate mosquito control measures. It is an emerging disease in Tamilnadu. Dengue virus is an enveloped ssRNA virus of 45-50 nm belonging to Genus flavivirus and Family flaviviridae. Dengue is transmitted by Aedes aegypti mosquitoes. It causes wide spectrum of illness ranging from undifferentiated illness to Dengue haemorrhagic fever and Dengue shock syndrome. Specific IgM and IgG detection has been the mainstay of diagnosis for a long time. Dengue specific antigen is found to be highly specific and reliable marker from the first day of diagnosis. AIM AND OBJECTIVES : To study the multivariate analysis of Dengue with serological differentiation of primary (PD) and secondary dengue (SD), comparative evaluation of Immunochromatography (ICT) with Immunocapture Enzyme Linked Immuno Sorbent Assay (ELISA) and special emphasis on Nonstructural protein( NS1) antigen as an early diagnostic marker . To correlate Dengue clinically with haematological and biochemical profile. MATERIALS AND METHODS : After taking informed consent, blood was drawn from three hundred and fifty suspected cases and were subjected to both ICT and ELISA.ELISA positive cases were analysed further. Accuracy indices of ICT were calculated using ELISA as reference assay. RESULTS : Out of 350 samples tested ,107 were positive by ELISA (30.5%) for one or more serological markers. The common age group affected were 0-10 years in both sexes with male : female ratio of 1.6:1.Incidence was high during November to December 2011& January , May, june & July 2012. Clinically seropositives were classified as Dengue fever, Dengue haemorrhagic fever and Dengue shock syndrome. There was significant association of thrombocytopenia, HCT and WBC count with Dengue fever, DHF and DSS. The107 seropositives by ELISA were categorized as primary and secondary dengue based on duration of fever and serological markers. Out of 107, 27 were positive for NS1only, 9 were positive for IgM alone, only 6 showed IgG alone. More than one marker was detected in the remaining 65 samples. In 48 primary dengue cases NS1 had higher positivity and in secondary dengue IgM&IgG ratio >1 had higher positivity. Sensitivity, specificity, PPV and NPV of the ICT were calculated using ELISA as reference for individual markers which showed moderate performance. Haematological and biochemical profile also showed statistical significance in association with Dengue fever, DHF and DSS. CONCLUSION : Inclusion of NSI in the routine diagnosis of dengue increases the detection rate of cases significantly in the early period. Irrespective of fever duration, all the three ELISA must be done to rule out Dengue infection like NS1, IgM, and IgG. Immunocapture ELISA is reliable and sensitive than ICT even though it is highly specific. Haematological and biochemical tests should also be given importance along with serological markers for dengue diagnosis and management.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Dengue ; Nonstructural protein ; Primary dengue ; Secondary dengue ; Immunochromatography ; Immunocapture ELISA ; Multivariate Analysis ; Tertiary Care Hosptial.
Subjects: MEDICAL > Microbiology
Depositing User: Subramani R
Date Deposited: 14 Aug 2017 04:51
Last Modified: 14 Aug 2017 04:51

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