Transmission mechanisms of vector-borne pathogens by blood-sucking insects

Under what circumstances does the growth and proliferation of pathogens be promoted and inhibited within the bodies of pathogen-transmitting blood-sucking insects (vectors)?The molecular mechanism of this event, which is directly linked to the success or failure and efficiency of pathogen transmission. is not clear. In this study, vectors were used in which the growth and proliferation ability of pathogens was disrupted by simple methods such as administration of antibiotics and rare sugars, and investigated molecules expressed in the midgut, which is the site of pathogen growth and proliferation within the vector. A summary of this year’s research results is as follows. 1) Genes whose expression changes after 1 and 3 days in Anopheles mosquitoes where malaria parasite infection was increased by antibiotic administration were analyzed using RNAseq and microarray. In RNAseq analysis, out of 13,611 molecules that increased by more than 4 times due to antibiotic administration, 572 molecules decreased after 1 day and 653 after 3 days, and 444 molecules decreased by 4 times or more after 1 day and 505 after 3 days. On the other hand, microarray analysis showed that of the 31,689 probes that increased by more than 4 times after antibiotic administration, 7 probes decreased after 1 day and 54 after 3 days, and 117 probes decreased by 4 times or more after 1 day and 58 after 3 days. The characteristics of the gene groups that have changed are still in the analysis stage. 2) the study analyzed the mechanism by which rare sugars inhibit the growth of malaria parasites within the body of Anopheles mosquitoes, focusing on intestinal bacteria. As a result, no major changes were observed in the composition of intestinal bacteria, but quantitative changes were observed. The study is currently investigating how this relates to the inhibition of protozoan infection. 3) The transient bacterial growth that occurs after mosquitoes feed on blood is thought to affect the oxygen status of the midgut. The effects of hypoxic responses on pathogen transmission was investigated in Anopheles mosquitoes using hypoxia-inducible factor (HIF) inhibitors. Infection experiments were conducted by administering multiple inhibitors to mosquitoes, but no effect was found on the transmission of malaria parasites to mosquitoes.

Project details

Basic Science
Vector Control

Apr 2020 — Mar 2024

$152,708

Japan