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Published on: August 7, 2018
Intrathoracic Inoculation of Zika Virus in Aedes aegypti
Irma Sanchez-Vargas1, Adeline E Williams1, Alexander W E Franz2
1Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO USA.
Abstract:
Aedes aegypti mosquitoes are the main vectors of many medically relevant arthropod-borne (arbo) viruses, including Zika (ZIKV), dengue (DENV), and yellow fever (YFV). Vector competence studies with Ae. aegypti often involve challenging mosquitoes with an artificial bloodmeal containing virus and later quantifying viral titer or infectious plaque-forming units (PFU) in various mosquito tissues at relevant time points post-infection. However, Ae. aegypti mosquitoes are known to exhibit midgut infection and escape barriers (MIB and MEB, respectively), which influence the prevalence and titer of a disseminated infection and can introduce unwanted variability into studies analyzing tissues such as the salivary glands. To surmount this challenge, we describe herein a protocol for the intrathoracic inoculation of ZIKV in Ae. aegypti. This method bypasses the midgut, which leads to a more rapid and higher proportion of disseminated infections in comparison to oral challenge, and mosquitoes become infected with a consistent dose of virus. Our protocol is advantageous for studies that need a large sample size of infected mosquitoes, need to bypass the midgut, or are analyzing salivary gland infection or escape barriers. Graphic abstract: Cartoon depiction of Figure made with Biorender.com.
Insights
Intrathoracic inoculation bypasses mosquito midgut barriers, enabling consistent Zika virus (ZIKV) infection. This method improves disseminated infection rates for arbovirus research.
Area of Science:
- Medical entomology
- Virology
- Infectious diseases
Background:
- Aedes aegypti mosquitoes transmit arboviruses like Zika (ZIKV), dengue (DENV), and yellow fever (YFV).
- Vector competence studies often use artificial bloodmeals, but midgut infection and escape barriers (MIB/MEB) in Ae. aegypti cause variability.
- These barriers affect infection prevalence and viral titers in mosquito tissues, complicating research.
Purpose of the Study:
- To describe a protocol for intrathoracic inoculation of ZIKV in Ae. aegypti.
- To provide an alternative method that bypasses the mosquito midgut barriers.
- To facilitate studies requiring consistent viral dosing and higher rates of disseminated infection.
Main Methods:
- Intrathoracic inoculation of ZIKV directly into the mosquito hemocoel.
- Bypassing the natural route of oral infection via a bloodmeal.
- Quantifying viral titer and infection dissemination in mosquito tissues post-inoculation.
Main Results:
- Intrathoracic inoculation leads to more rapid and higher proportions of disseminated ZIKV infections.
- This method ensures mosquitoes receive a consistent dose of virus, reducing experimental variability.
- The protocol is suitable for generating large sample sizes of infected mosquitoes.
Conclusions:
- Intrathoracic inoculation is a valuable method for ZIKV studies in Ae. aegypti.
- It overcomes limitations posed by midgut barriers, enhancing experimental reproducibility.
- This technique is advantageous for research on salivary gland infections and vector competence.
