Learning more about mosquito transmission may help flavivirus vaccine development

Mosquitoes transmit infectious diseases like dengue, zika, yellow fever and West Nile.  These diseases are part of the flavivirus disease family and can cause varying degrees of illness in a person if they become infected. CIR's director and infectious diseases expert, Dr. Anna Durbin  leads Team FIRE (Flavivirus Immunization Research and Education) in clinical research efforts to develop vaccines for Dengue, Zika and other viruses.  

An early part of identifying a safe and effective vaccine candidate is determining how the virus behaves when a person is infected.  One way to accomplish this is to conduct challenge studies, where the virus is intentionally given to study participants and their response to the virus is closely studied.  Team FIRE is conducting a zika challenge study in which males between 18-40 years old are admitted into CIR's inpatient unit for about 10 days.  During the admission, participants are given one of two zika strains that are being considered for use in a zika vaccine.  After being challenged with zika, participants must allow mosquitoes to feed on them for several minutes a day for 3 days.  The study procedure is being done to help determine whether mosquitoes who feed on infected people will then transmit the virus to others. Learning more about this process may help scientists determine the best route to zika vaccine development.

Mosquitoes used for this portion of the study are bred in a laboratory.  Several of them are placed in mesh-covered containers which are placed against the study participants skin to allow them to feed.  Researchers must ensure that enough of the mosquitoes have fed on the participant before ending the session, which lasts between 10-20 minutes. 

After the feeding, researchers sort out the mosquitoes that fed for later evaluation.  William Stone, a pre doctoral fellow working on the study demonstrates this sorting process. Once the testing is completed, researchers hope to have more information about the transmission of zika virus from person to mosquito. 

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