The Anopheles stephensi species is one of the main spreaders of human malaria. By altering its salivary glands, the mosquito acts as a “flying vaccinator,” carrying the Leishmania vaccine within its saliva. About 60 species of the Anopheles are vectors of the malaria parasite, which are transmitted to humans when the female feeds on blood.
Tests showed that when an altered mosquito bit its host — in this case laboratory mice — it became a transmitter of the vaccine. The bites succeeded in raising antibodies in the mice, indicating successful immunization with the vaccine.
It’s hoped that continuous exposure to bites will maintain high levels of protective immunity, through natural boosting, for a lifetime.
Researchers hope the vaccinator mosquitoes could be used to formulate a new strategy in the global fight against malaria. Every year about 250 million people are infected with malaria, and nearly one million die, according to the World Health Organization. In Africa, one in every five childhood deaths is caused by malaria.
There are, however, barriers to using this form of vaccination in the wild, including issues of controlling dosage, “medical safety issues” and the “issues of public acceptance to [the] release of transgenic mosquitoes.” It may not be as romantic as sundowners of gin and tonic (quinine is an old school anti-malarial), but it sure beats the potential side effects of Lariam.