Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New Insights Into Mosquitoes’ Role as Involuntary Bioterrorists

Mosquitos are involuntary bioterrorists.

For many years scientists thought that mosquitoes provided the disease organisms which they spread with a relatively free ride because the insects didn’t have much in the way of natural defenses to fight off these microscopic stowaways.

Hillyer Lab / Vanderbilt University

This microscopic fluorescent image of the mosquito's circulatory system shows muscle cells in green; cellular DNA in blue and periostal hemocytes in orange.

Recent research, however, has revealed that mosquitoes have surprisingly sophisticated immune systems. Unlike humans and most other animals, mosquitoes do not generate antibodies that identify and attack specific infectious agents. However, they have developed alternative methods for destroying various pathogens, including parasites that cause malaria.

In the latest study of the mosquito’s immune system – published online on Nov. 29 in the journal PLOS Pathogens – a pair of Vanderbilt biologists have discovered mosquitoes possess a previously unknown mechanism for destroying pathogens that takes advantage of the peculiarities of the insect’s circulatory system to increase its effectiveness.

Studies of this sort are providing the information needed to manipulate the mosquito immune system to block malaria parasites more effectively and to develop other novel disease control strategies.

“It may come as a surprise to many people, but mosquitoes get sick too and they need to protect themselves,” said Julián Hillyer, assistant professor of biological sciences, who conducted the research with graduate student Jonas King.

“The mosquito’s immune system isn’t as complex as ours. About 350 of its 12,500 genes have immune functions,” Hillyer said. “But it is remarkably effective. The vast majority of the malaria parasites that infect a mosquito die before they can get into the salivary glands where they can infect vertebrate prey, such as humans.”

“Pathogens like those that cause malaria, dengue and yellow fevers come from the female’s blood meal and end up in the mosquito’s gut,” Hillyer said. “They then leave the gut and enter the mosquito’s main body cavity, and from there they have to make their way to its salivary glands.”

Inside the body cavity, pathogens have to fight two main forces: the swift circulation of the mosquito’s own blood, and attacks from the mosquito’s immune system.

The mosquito’s circulatory system is dramatically different from that of mammals and humans. A long tube extends from the insect’s head to tail and is hung just under the cuticle shell that forms the mosquito’s back. The heart makes up the rear two-thirds of the tube and consists of a series of valves within the tube and helical coils of muscle that surround the tube. These muscles cause the tube to expand and contract, producing a worm-like peristaltic pumping action.

Most of the time, the heart pumps the mosquito’s blood—a clear liquid called hemolymph—toward the mosquito’s head, but occasionally it reverses direction. The mosquito doesn’t have arteries and veins like mammals. Instead, the blood flows from the heart into the abdominal cavity and eventually cycles back through the heart. “The mosquito’s heart works something like the pump in a garden fountain,” Hillyer said.

In order to make it to their goal, pathogens must pass through one of the heart valves. As a result, the valves act as physical bottlenecks during the migration of viruses and malaria parasites.

Cells called hemocytes are an important element in the mosquito’s defense system. These are special immune cells carried in the hemolymph that play a role analogous to white blood cells in humans. They circulate around the body with the hemolyph and attack foreign cells and viruses when they contact them.

What Hillyer and King discovered was that when a mosquito becomes infected with bacteria or malaria parasites, a population of hemocytes is recruited to the valves of the heart, where they capture and destroy invading pathogens. These new mosquito immune cells, which they have named periostial hemocytes, substantially increase their odds of encountering and destroying invaders by congregating in areas of high hemolymph flow.

“What happens to these pathogens while they are carried inside the mosquito’s body is a critical part of the infection cycle that we are just beginning to understand,” said Hillyer.

This research was funded by the National Science Foundation grant number IOS-1051636.

Visit Research News @ Vanderbilt for more research news from Vanderbilt. [Media Note: Vanderbilt has a 24/7 TV and radio studio with a dedicated fiber optic line and ISDN line. Use of the TV studio with Vanderbilt experts is free, except for reserving fiber time.]

David F. Salisbury | Vanderbilt University
Further information:

More articles from Life Sciences:

nachricht First time-lapse footage of cell activity during limb regeneration
25.10.2016 | eLife

nachricht Phenotype at the push of a button
25.10.2016 | Institut für Pflanzenbiochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>