Malaria scientist decodes the world's deadliest parasites

The malaria mosquito is spreading some of the world's deadliest diseases, but not on its own. It is controlled by ancient parasites that use their code language to make their host, human or animal, act in a way that benefits its survival. A code language that molecular biologist Noushin Emami at Stockholm University is working to decode.

“I am trying to learn the language of parasites so that we can stop the spread of infection by breaking their cycles. The problem is that we humans have only been around for about a million years while the parasites have been around for 40 million years. They have learned how to survive and are very smart creatures”, says malaria researcher Noushin Emami.

Noushin Emami tittar in i värmeskåp för myggor

In the lab, there are two large 'refrigerators' filled with mosquitoes and mosquito larvae. The conditions in the cabinet are the same as around the equator. Photo: Anette Gärdeklint Sylla/Stockholm University

Mosquitos in search of blood

She opens the doors to a large heating cabinet filled with malaria mosquitoes and larvae. Inside, the temperature is 27 degrees Celsius and the humidity is 70 percent. There is daylight for 12 hours a day and darkness for the same amount of time, mimicking African conditions around the equator. On the shelves are cages covered with size XXL nylon stockings bought online. Mosquitoes buzz in the cages, eager to bite when they smell human blood.

“They get the urge to mate when they smell us. Look, there is a couple mating”, she says, pointing into the cage. She can distinguish females and males with the naked eye and can see when a female is about to lay eggs.

But the mosquito is not in focus

Blood is a prerequisite for them to lay eggs. Only female mosquitoes suck blood from humans. The mosquito is otherwise a herbivore. Twenty-four hours after sucking blood, a mosquito lays its eggs, often around sixty of them. But it is not the mosquitoes that interest Noushin Emami, but the malaria parasites that invade them. She is driven by a desire to understand the parasites to outsmart them.

The cages with mosquitoes are covered with XXL nylon stockings. Inside, mosquitoes buzz around, eager to bite when they smell human blood. Photo: Anna Karin Landin/Stockholm University

The malaria cycle from mosquito to human

An infected mosquito bites a human and transfers so-called sporozoites to the human bloodstream.
The sporozoites travel to the liver where they grow and take on a new form, known as merozoites.
Merozoites can invade our blood cells, which they eat from within.
Once all the blood is consumed, the person dies and the parasites have to find a new victim to live on.

A parasite with the ability to change DNA

And it is here, in the dying victim, that the magic happens. To get out of the body, the parasite uses a chemical reaction to change the human scent to make it more attractive to mosquitoes. Noushin Emami uses gestures to show how a whole swarm of mosquitoes seek out a sick person and bite. In this way, the parasite is passed on to new mosquitoes, which can then bite new victims in an endless cycle.

“Parasites can change the DNA of an organism. The scent is part of the parasite's external code language. To fight the spread of malaria, we must learn to decipher the code to understand the parasites' signals”.

Mosquitos are victimes

The mosquito is also a victim of the parasite just like humans, although it does not die but only passes on the infection. Like inside a human, the parasite can change the mosquito's DNA to make it more bite-prone and aggressive.

“Parasites are not evil. They just want to survive. We just need to understand them and start communicating with them. We always see it as a bad thing that they exist, but if we learn to communicate with them, maybe they can help us instead of causing harm”.

On a whiteboard, Noushin Emami shows how the parasite grows inside a mosquito's body. Photo: Anette Gärdeklint Sylla/Stockholm University

Groundbreaking research results

Eco-friendly poison cocktail new weapon against malaria

One of the findings of Noushin Emami's research into the code language of parasites is that mosquitoes can be tricked into ingesting beetroot-based mixtures of toxins instead of blood. The poison is not dangerous to the environment but kills the mosquito within a few hours.

“The mixture, which we call 'pink juice', is a harmless, viscous, environmentally hazardous solution, which is naturally toxic to female mosquitoes that eat it”, says Noushin Emami.
Read more about the research results

Scents control malaria mosquito reproduction

Her research has also led to new methods of influencing the mating processes of mosquitoes to control the mosquito population.
Read more about the research results

Facts about vector-borne infections

Infections spread by insects or arachnids are called vector-borne infections. Infectious agents, known as pathogens, are usually found inside the vector (insect or arachnid) and are passed on through bites. In Sweden, Borrelia and tick-borne encephalitis (TBE) are spread in this way.
A vector is an organism that carries the infection but does not cause the disease itself. However, the vector can transmit a parasite or other infectious agent that can cause disease. Examples of vectors are the malaria mosquito that spreads malaria and bats that can spread rabies. There are both mechanical vectors, where the vector only moves the infectious agent physically, and biological vectors that help the infectious agent go through a necessary stage in its development. Biological vectors are often negatively affected by the infectious agent and also become ill, such as the malaria mosquito.
Vector-borne diseases account for over 17% of all infectious diseases and lead to more than 700,000 deaths per year. Of these, malaria accounts for around 600,000 deaths per year.
Only 2% of the world's 3 600 mosquito species suck blood, mainly Anopheles, Culex and Aedes, which spread malaria parasites, Zika virus, Chikungunya, West Nile and dengue virus. Only the female mosquito sucks blood, and only to lay her eggs.
Vector control is any method to contain or eradicate mammals, birds, insects or other arthropods that transmit disease pathogens. The most common type of vector control is mosquito control using a variety of strategies.

More about Noushin Emami's research

Funding of the research

Noushin Emami's research project on the code language of parasites is funded by Audrey Capital 2008, an investment and research company founded by American web developer and entrepreneur Matt Mullenweg, founder of WordPress. Through Audrey Capital, Noushin Emami has received a grant of $100,000 per year for three years.

Matt Mullenweg is also behind the WordPress Foundation and the WordPress open source project, an organization whose mission is to democratize publishing through open source.