Understanding the Dengue Virus : Symptoms, Transmission, and Prevention.

Understanding the Dengue Virus : Symptoms, Transmission, and Prevention.

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  DENGUE VIRUSES S. NahidhaBegum II. M.Sc Microbiology Sacred Heart College
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  DENGUE VIRUSES Introduction Dengue isa viral infection transmitted by mosquitoes. There are four serotypes of the dengue virus: DEN-1, DEN-2, DEN-3, and DEN-4. The illness caused by dengue ranges from mild fever to severe, life- threatening conditions.
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  PROPERTIES OF DENGUEVIRUS Arbovirus  Belongs to the family Flaviviridae and genus Flavivirus  Transmitted by arthropods, primarily mosquitoes. Dengue Serotypes  Four serotypes: DEN-1, DEN-2, DEN-3, DEN-4.  Serotypes differ in genetic makeup, antigenic properties, and geographic distribution. Mosquito Vector  The primary vector is Aedes aegypti, a mosquito that bites during the day.
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  STRUCTURE OF DENGUEVIRUS Shape: Spherical and enveloped, approximately 50 nm in diameter. Envelope: Contains glycoproteins that facilitate virus attachment and entry into host cells. Genome: Composed of a single-stranded, positive-sense RNA, roughly 11 kb in length. Proteins: Encodes for three structural and seven non-structural proteins necessary for virus replication.
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  DENGUE VIRUS REPLICATIONMECHANISM  Attachment: Virus attaches to host cell receptors, initiating endocytosis.  Uncoating: The virus releases its RNA genome into the cytoplasm.  Translation: The viral RNA is translated into polyproteins.  Proteolytic Processing: Polyproteins are cleaved into individual viral proteins by cellular and viral proteases.  Replication: Genomic RNA is used as a template for synthesizing new RNA and viral proteins.  Assembly and Release: New virus particles are assembled and released from the cell.
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  PATHOGENESIS OF DENGUEVIRUS  Infection of Dendritic Cells: The virus enters dendritic cells in the skin via mosquito bites.  Dissemination via Lymphatics: The virus spreads through the lymphatic system to other tissues.  Platelet Activation: Infected platelets activate and release inflammatory cytokines and chemokines.
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  TRANSMISSION MODES OFDENGUE VIRUS Mosquito Bites: Transmitted by Aedes aegypti and Aedes albopictus mosquitoes. Vertical Transmission: From mother to fetus during pregnancy or childbirth. Blood Transfusion: Through infected blood transfusion or organ transplantation. Sexual Transmission: Rare, but possible.
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  SYMPTOMS AND CLINICALMANIFESTATIONS Mild Dengue Fever:  Fever  Headache  Retro-orbital pain  Muscle and joint pain  Rash Severe Dengue Fever:  Severe headache  Joint and muscle pain
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  SYMPTOMS AND CLINICALMANIFESTATIONS  Bleeding manifestations  Plasma leakage  Organ impairment Dengue Shock Syndrome:  Severe plasma leakage  Hypotension  Shock  Organ failure
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  LABORATORY DIAGNOSIS Serology: Detectionof IgM and/or IgG antibodies to dengue virus.  Molecular: RT-PCR to detect viral RNA. Virus Isolation: Growth in cell culture or animal models.
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  TREATMENT AND PREVENTION Treatment:  No specific treatment; supportive care with antipyretics and analgesics.  Prevention:  Mosquito control  Use of protective clothing and mosquito repellents  Vaccination:  CYD-TDV vaccine (a live recombinant tetravalent vaccine) provides partial protection against dengue.
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