Intestinal bacteria to fight malaria

In 2021, the World Health Organization (WHO) has estimated 247 million cases of malaria in the world. Despite advances in medicine, protection against the disease remains incomplete.

𝐌𝐚𝐥𝐚𝐫𝐢𝐚 𝐢𝐬 𝐜𝐚𝐮𝐬𝐞𝐝 𝐛𝐲 𝐩𝐥𝐚𝐬𝐦𝐨𝐝𝐢𝐮𝐦 𝐩𝐚𝐫𝐚𝐬𝐢𝐭𝐞𝐬, which are transmitted to humans through the bite of female Anopheles mosquitoes. Researchers have discovered that some of these mosquitoes harbor 𝐟𝐞𝐰𝐞𝐫 𝐩𝐚𝐫𝐚𝐬𝐢𝐭𝐞𝐬 𝐭𝐡𝐚𝐧 𝐨𝐭𝐡𝐞𝐫𝐬. This was due to the presence of 𝐚 𝐧𝐚𝐭𝐮𝐫𝐚𝐥 𝐞𝐧𝐝𝐨𝐬𝐲𝐦𝐛𝐢𝐨𝐭𝐢𝐜 𝐛𝐚𝐜𝐭𝐞𝐫𝐢𝐮𝐦, Delftia tsuruhatensis, in the mosquito's intestinal microbiota. Mosquitoes carrying these bacteria had 75% fewer oocytes in their gut.

In addition, the researchers found that only one-third of rodents bitten by mosquitoes carrying both plasmodium and the bacteria became infected, whereas 100% of mice bitten by mosquitoes carrying the parasite without the bacteria developed the disease. D.tsuruhatensis likely 𝐫𝐞𝐝𝐮𝐜𝐞𝐬 𝐭𝐡𝐞 𝐭𝐫𝐚𝐧𝐬𝐦𝐢𝐬𝐬𝐢𝐨𝐧 𝐜𝐚𝐩𝐚𝐜𝐢𝐭𝐲 𝐨𝐟 𝐩𝐥𝐚𝐬𝐦𝐨𝐝𝐢𝐮𝐦. Specifically, this bacterium secretes 𝐚 𝐭𝐨𝐱𝐢𝐧, 𝐤𝐧𝐨𝐰𝐧 𝐚𝐬 𝐡𝐚𝐫𝐦𝐚𝐧𝐞, which inhibits the early stages of the parasite's development during the sexual phase in the mosquito's digestive tract.

Harmane is also present in plant extracts used in traditional cooking and medicine in Mali. However, it is hallucinogenic for humans at high doses. Further investigations shall provide 𝐧𝐞𝐰 𝐭𝐨𝐨𝐥𝐬 𝐢𝐧 𝐭𝐡𝐞 𝐟𝐢𝐠𝐡𝐭 𝐚𝐠𝐚𝐢𝐧𝐬𝐭 𝐦𝐚𝐥𝐚𝐫𝐢𝐚.