New research, conducted by Houston’s Baylor College of Medicine, reveals that a mosquito bite has an effect on our immune system even after the itch is gone.
In fact, the immune response from a mozzie bite can last for up to seven days, according to Dr. Rebecca Rico-Hesse and her colleagues.
A study was carried out on mice with human stem cells that measured the effects of mozzie saliva on immune responses. After the poor mice were bitten by mosquitoes (uninfected with any pathogens), researchers analysed the changes in their immune cells.
Over a period of six hours, 24 hours and seven days, these “humanised” mice showed immune responses that included altered Th1 and Th2 helper cells and an increase in the levels of cytokines.
There was also an increase in levels of natural killer T cells, natural killer cells, CD8+ T cells, monocytes, and macrophages.
Researchers also observed humanised mice that hadn’t been bitten by mosquitoes.
What’s surprising is that mice immune responses lasted up to 7 days following mosquito bites. The number of immune cell types affected is also much larger than what researchers previously thought.
“The biological significance of these changes remains to be determined, but it might explain how some pathogens, such as viruses, can spread through the body in these cells, replicate to higher extents, and even remain in some tissues for far longer than detected in blood”, the researchers wrote.
With 750,000 people around the world dying every year due to mosquito-borne diseases, researchers believe “understanding how mosquito saliva interacts with the human immune system not only helps [them] understand mechanisms of disease pathogenesis but also could provide possibilities for treatments”.
Research into mosquito bites doesn’t stop here. Baylor College of Medicine researchers will next investigate which of the 100+ proteins in mosquito saliva are affecting immune systems.
Researchers note that identifying these proteins could actually help them in creating strategies for fighting the transmission of dengue fever, as well as other diseases such as Zika virus, yellow fever, and chikungunya virus.