Researchers have produced a model of the Anopheles stephensi mosquito, which is a major source of malaria in India and the Middle East, that impairs the development of the malaria parasite.
These mosquitoes, in turn, cannot transmit the disease through their bites.
According to UC Irvine scientists, mosquitoes bred to be unable to infect people with the malaria parasite are an attractive approach to helping curb one of the world’s most pressing public health issues.
“Our group has made significant advances with the creation of transgenic mosquitoes,” Anthony James, from UCI, said.
“But this is the first model of a malaria vector with a genetic modification that can potentially exist in wild populations and be transferred through generations without affecting their fitness,” he said.
More than 40 percent of the world’s population lives in areas where there is a risk of contracting malaria.
According to the Centers for Disease Control and Prevention, 300 million to 500 million cases of malaria occur each year, and nearly 1 million people die of the disease annually — largely infants, young children and pregnant women, most of them in Africa.
James said one advantage of his group’s method is that it can be applied to the dozens of different mosquito types that harbour and transmit the Plasmodium falciparum parasite, including those in Africa.
The researchers conceived their approach through mouse studies. Mice infected with the human form of malaria create antibodies that kill the parasite.
James’ team exploited the molecular components of this mouse immune-system response and engineered genes that could produce the same response in mosquitoes. In their model, antibodies are released in genetically modified mosquitoes that render the parasite harmless to others.
“We see a complete deletion of the infectious version of the malaria parasite,” James said.
“This blocking process within the insect that carries malaria can help significantly reduce human sickness and death,” he said.
He and his colleagues have pioneered the creation of genetically altered mosquitoes that limit the transmission of dengue fever, malaria and other vector-borne illnesses.
Alison Isaacs, Nijole Jasinskiene and Mikhail Tretiakov of UCI and Isabelle Thiery, Agnes Zettor and Catherine Bourgouin of the Pasteur Institute contributed to the study, which received support from the National Institute of Allergy and Infectious Diseases.
The study has been published in the early online version of the Proceedings of the National Academy of Sciences.