How does the transmission of dengue occur?

Updated: May 03, 2019
  • Author: Darvin Scott Smith, MD, MSc, DTM&H; Chief Editor: Michael Stuart Bronze, MD  more...
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Answer

The mosquito can transmit dengue if it immediately bites another host. In addition, transmission occurs after 8-12 days of viral replication in the mosquito's salivary glands (extrinsic incubation period). The virus does not adversely affect the mosquito. The mosquito remains infected for the remainder of its life. The life span of A aegypti is usually 21 days but ranges from 15 to 65 days. Vertical transmission of dengue virus in mosquitoes has been documented. [19] The eggs of Aedes mosquitoes withstand long periods of desiccation, reportedly as long as 1 year, but are killed by temperatures of less than 10°C. Rare cases of vertical dengue transmission have been reported. In addition, rare reports of human-to-human transmission via needle-stick injuries have been published. [20]

Once inoculated into a human host, dengue has an incubation period of 3-14 days (average 4-7 days) while viral replication takes place in target dendritic cells. Infection of target cells, primarily those of the reticuloendothelial system, such as dendritic cells, macrophages, hepatocytes, and endothelial cells, [21, 22, 23, 24] result in the production of immune mediators that serve to shape the quantity, type, and duration of cellular and humoral immune response to both the initial and subsequent virus infections. [21, 25, 26, 27, 28, 29, 30]


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