Mosquito spit may affect your immune system for days

May 17, 2018, Public Library of Science
Mosquito spit may affect your immune system for days. Credit: Rico-Hesse et al, 2018

Mosquito saliva alone—even in the absence of any pathogens—contains hundreds of proteins. Now, researchers reporting in PLOS Neglected Tropical Diseases have discovered that the interaction of these proteins with the human immune system causes an immune response that can be detected for days after a mosquito bite.

Around the globe, 750,000 people a year die of mosquito-transmitted diseases, including malaria, dengue, West Nile, Zika, and chikungunya fever. Previous studies have shown that properties of a mosquito bite—including mosquito saliva—exacerbate some of these diseases; in mice, infections caused by a mosquito bite are often more severe than those caused by needle injection of the parasite.

In their new work, Rebecca Rico-Hesse, of Baylor College of Medicine, USA, and colleagues studied the effect of mosquito bites on in mice engrafted with human hematopoietic stem cells—leading the animals to have components of a human immune system. They studied small changes in the levels and functions of these immune cells after each mouse was bitten by four on their footpads.

After getting bitten by mosquitoes uninfected with any pathogen, the humanized mice showed multiple types of human immune responses, with altered Th1 and Th2 T helper cells and an increase in the levels of cytokines. At various points during the immune responses, there were also increases to levels of natural killer T cells, , CD8+ T , mononocytes, and macrophages. Overall, evidence of the immune responses lasted up to 7 days post-bite and were seen in multiple tissue types, including the blood, skin and bone marrow.

"Understanding how mosquito saliva interacts with the human immune system not only helps us understand mechanisms of disease pathogenesis but also could provide possibilities for treatments," the researchers say.

Explore further: Study explores new strategy to develop a malaria vaccine

More information: Vogt MB, Lahon A, Arya RP, Kneubehl AR, Spencer Clinton JL, et al. (2018) Mosquito saliva alone has profound effects on the human immune system. PLOS Neglected Tropical Diseases 12(5): e0006439. doi.org/10.1371/journal.pntd.0006439

Related Stories

Study explores new strategy to develop a malaria vaccine

April 11, 2018
A serum developed by Yale researchers reduces infection from malaria in mice, according to a new study. It works by attacking a protein in the saliva of the mosquitos infected with the malaria parasite rather than the parasite ...

Inflammation from mosquito bites may enhance viral infection

June 21, 2016
The itchy, red welts that appear after being bitten by a mosquito may help any viruses the insect is carrying pass on to a new host. A mouse study published June 21 in Immunity suggests that the swelling and irritation that ...

New clue to how mosquitoes fend off malaria

January 24, 2017
(Medical Xpress)—A team of researchers at the National Institutes of Health has found another part of the process that allows mosquitoes to keep from getting malaria even as they carry the parasite responsible for the disease ...

Human antibodies undermine parasite sex

February 8, 2018
Some people develop an immune response following a malaria infection that stops them from infecting other mosquitoes. The antibodies that these people produce are ingested by the mosquito and destroy the malaria parasite ...

Mosquito saliva increases disease severity following dengue virus infection

June 16, 2016
Insects transmit diseases when, probing for blood vessels, they inject saliva together with viral, bacterial, or parasitic pathogens into the skin of mammalian hosts. A study in mice published on June 16, 2016 in PLOS Pathogens ...

Monkeys infected by mosquito bites further Zika virus research

December 13, 2017
Monkeys who catch Zika virus through bites from infected mosquitoes develop infections that look like human Zika cases, and may help researchers understand the many ways Zika can be transmitted.

Recommended for you

New hope for cystic fibrosis

October 19, 2018
A new triple-combination drug treatment being trialled at the Mater Hospital in Brisbane could increase the life expectancy of patients with cystic fibrosis.

Bug guts shed light on Central America Chagas disease

October 18, 2018
In Central America, Chagas disease, or American trypanosomiasis, is spread by the "kissing bug" Triatoma dimidiata. By collecting DNA from the guts of these bugs, researchers reporting in PLOS Neglected Tropical Diseases ...

Rapid genomic sequencing of Lassa virus in Nigeria enabled real-time response to 2018 outbreak

October 18, 2018
Mounting a collaborative, real-time response to a Lassa fever outbreak in early 2018, doctors and scientists in Nigeria teamed up with researchers at Broad Institute of MIT and Harvard and colleagues to rapidly sequence the ...

Researchers cure drug-resistant infections without antibiotics

October 17, 2018
Biochemists, microbiologists, drug discovery experts and infectious disease doctors have teamed up in a new study that shows antibiotics are not always necessary to cure sepsis in mice. Instead of killing causative bacteria ...

Infectious disease consultation significantly reduces mortality of patients with bloodstream yeast infections

October 17, 2018
In a retrospective cohort study conducted at the University of Alabama at Birmingham Division of Infectious Diseases, patients with candidemia—a yeast infection in the bloodstream—had more positive outcomes as they relate ...

How drug resistant TB evolved and spread globally

October 17, 2018
The most common form of Mycobacterium tuberculosis (TB) originated in Europe and spread to Asia, Africa and the Americas with European explorers and colonialists, reveals a new study led by UCL and the Norwegian Institute ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.