Dengue Pathogenesis

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The dengue virus belongs to the family of Flaviviridae, genus Flavivirus. It is also known as Arbovirus ( arthropod- borne virus) as it belongs to group of virus that is transmitted by an arthropod or mosquito ( Medical Microbiology; pg 554). The dengue virus is of the size of 40- 65 nm in diameter, roughly spherical and has outer lipid envelope. It is a positive stranded RNA genome made up of 10 000 nucleotide base pairs. The RNA genome contains a single open reading frame that encodes a precursor polyprotein, which is co- and post-translationally cleaved into three structural (C, prM and E) and seven non-structural (NS1, NS2A, NS2B, NS3, NS4A, NS4B, NS5) proteins. The core of the virus is surrounded by nucleocapsid which is a structure that …show more content…

The pathogenesis of this self limiting dengue can be broadly divided into 2 categories, that is:

(a) The general pathogenesis of the virus, beginning from the entry to the body till the cause of fever.
(b) The dengue virus replication and infectious cycle which occurs in the cell

5.2.3.1 General pathogenesis of dengue fever

When a mosquito carrying dengue virus bites a person, the virus enters the skin together with the mosquito's saliva. It binds to and enters white blood cells (specifically the immature dendritic cell or Langerhans cell located in the skin), and reproduces inside the cells while they move throughout the body. The white blood cells respond by producing a number of signalling proteins, such as cytokines and interferon, which are responsible for many of the symptoms, such as the fever and severe pains. However it is to be noted that this fever is actually self limiting. The overview of the pathogenesis of the virus is illustrated in Figure 2 and Flowchart …show more content…

neutralizing antibody and non neutralizing antibody. When the same individual is infected with different dengue serotype, DHF or DSS results. (For example, he is infected with DENV 1 and then re infected by DENV2). This is because the virus infects the body cells following the general pathogenesis (See under Pathogenesis of Dengue Fever) and another pathway is the ADE mechanism. The ADE mechanism is nothing but the non neutralizing antibody will ‘help’ the virus to gain entry into the cell (Figure 4). Thus, this will result in higher number of target cell being infected which in turn could lead to a higher viral load which was observed in many studies ( PubMed; Oct 2009; Dengue virus pathogenesis: An Integrated View; Byron E. E. Martino et

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