Mosquito saliva allows some virus to spread via the immune system – June 2016

How Mosquito Spit Might Affect Zika Risk NBC News June 21

They injected mice with a mosquito virus, both with and without mosquito spit

  • "We now want to look at whether medications such as anti-inflammatory creams can stop the virus establishing an infection if used quickly enough after the bite inflammation appears.”
  • "We think creams might act as an effective way to stop these viruses before they can cause disease.”

The study was received Aug 20, 2015 and published June 21, 2016

Host Inflammatory Response to Mosquito Bites Enhances the Severity of Arbovirus Infection Cell, June 2016

Highlights

  • Mosquito bites enhance virus replication and dissemination and increase host mortality
  • Neutrophil-driven inflammation retains virus in skin to drive macrophage recruitment
  • Recruited and resident myeloid cells become infected and replicate virus
  • Blocking leukocyte recruitment to bite site inhibits viral infection

Summary
Aedes aegypti mosquitoes are responsible for transmitting many medically important viruses such as those that cause Zika and dengue. The inoculation of viruses into mosquito bite sites is an important and common stage of all mosquito-borne virus infections. We show, using Semliki Forest virus and Bunyamwera virus, that these viruses use this inflammatory niche to aid their replication and dissemination in vivo. Mosquito bites were characterized by an edema that retained virus at the inoculation site and an inflammatory influx of neutrophils that coordinated a localized innate immune program that inadvertently facilitated virus infection by encouraging the entry and infection of virus-permissive myeloid cells. Neutrophil depletion and therapeutic blockade of inflammasome activity suppressed inflammation and abrogated the ability of the bite to promote infection. This study identifies facets of mosquito bite inflammation that are important determinants of the subsequent systemic course and clinical outcome of virus infection.

 Download the study from VitaminDWiki

Note: This study did NOT use Zika virus
Note: 80% of those bitten by a Zika mosquito have no inflammation
  Is a strong immune system associated with no inflammation?


See also VitaminDWiki

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