This work was supported by the Wuhan Science and Technology Plan Project (2018201261638501).

1. Preparation of viruses and mosquitoes
<ol>
	<li>Preparation of viruses 
	NOTE: All processes were carried out in a biosafety level 2 (BSL-2) laboratory. The level of biosafety contaiment used should be&#160;determined by the pathogen&#39;s risk assessment and regulations specific to nations and regions. The process must be performed in a biosafety cabinet.
	<ol>
		<li>Inoculate 1 x 106 C6/36 cells into a T75 culture flask. Fill the flask with 10 mL of Roswell Park Memorial Institute ...

<ol>
	<li>Yu, X., Zhu, Y., Xiao, X., Wang, P., Cheng, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progress+towards+Understanding+the+Mosquito-Borne+Virus+Life+Cycle.">Progress towards Understanding the Mosquito-Borne Virus Life Cycle.</a> Trends in Parasitology. 35 (12), 1009-1017 (2019).</li><li>Sukhralia, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=From+dengue+to+Zika:+the+wide+spread+of+mosquito-borne+arboviruses.">From dengue to Zika: the wide spread of mosquito-borne arboviruses.</a> European Journal of Clinical Microbiology &amp; Infectious Diseases. 38 (1), 3-14 (2019).</li><li>Kuhn, J. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Taxonomic+update+of+phylum+Negarnaviricota+(Riboviria:+Orthornavirae),+including+the+large+orders+Bunyavirales+and+Mononegavirales.">Taxonomic update of phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales.</a> Archives of Virology. 166 (12), 3513-3566 (2021).</li><li>Bhatt, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+global+distribution+and+burden+of+dengue.">The global distribution and burden of dengue.</a> Nature. 496 (7446), 504-507 (2013).</li><li>Kindhauser, M. K., Allen, T., Frank, V., Santhana, R. S., Dye, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zika:+the+origin+and+spread+of+a+mosquito-borne+virus.">Zika: the origin and spread of a mosquito-borne virus.</a> Bull World Health Organ. 94 (9), 675-686 (2016).</li><li>Wei, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vector+Competence+for+DENV-2+Among+Aedes+albopictus+(Diptera:+Culicidae)+Populations+in+China.">Vector Competence for DENV-2 Among Aedes albopictus (Diptera: Culicidae) Populations in China.</a> Frontiers in Cellular and Infection Microbiology. 11, (2021).</li><li>Morales-Vargas, R. E., Misse, D., Chavez, I. F., Kittayapong, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vector+Competence+for+Dengue-2+Viruses+Isolated+from+Patients+with+Different+Disease+Severity.">Vector Competence for Dengue-2 Viruses Isolated from Patients with Different Disease Severity.</a> Pathogens. 9 (10), (2020).</li><li>Naslund, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Emerging+Mosquito-Borne+Viruses+Linked+to+Aedes+aegypti+and+Aedes+albopictus:+Global+Status+and+Preventive+Strategies.">Emerging Mosquito-Borne Viruses Linked to Aedes aegypti and Aedes albopictus: Global Status and Preventive Strategies.</a> Vector-Borne and Zoonotic Diseases. 21 (10), 731-746 (2021).</li><li>Lwande, O. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Globe-Trotting+Aedes+aegypti+and+Aedes+albopictus:+Risk+Factors+for+Arbovirus+Pandemics.">Globe-Trotting Aedes aegypti and Aedes albopictus: Risk Factors for Arbovirus Pandemics.</a> Vector-Borne and Zoonotic Diseases. 20 (2), 71-81 (2020).</li><li>Liu-Helmersson, J., Brannstrom, A., Sewe, M. O., Semenza, J. C., Rocklov, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimating+Past,+Present,+and+Future+Trends+in+the+Global+Distribution+and+Abundance+of+the+Arbovirus+Vector+Aedes+aegypti+Under+Climate+Change+Scenarios.">Estimating Past, Present, and Future Trends in the Global Distribution and Abundance of the Arbovirus Vector Aedes aegypti Under Climate Change Scenarios.</a> Fronters in Public Health. 7, 148 (2019).</li><li>Cai, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+2021+China+report+of+the+Lancet+Countdown+on+health+and+climate+change:+seizing+the+window+of+opportunity.">The 2021 China report of the Lancet Countdown on health and climate change: seizing the window of opportunity.</a> Lancet Public Health. 6 (12), 932-947 (2021).</li><li>Chan, K. K., Auguste, A. J., Brewster, C. C., Paulson, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vector+competence+of+Virginia+mosquitoes+for+Zika+and+Cache+Valley+viruses.">Vector competence of Virginia mosquitoes for Zika and Cache Valley viruses.</a> Parasites &amp; Vectors. 13 (1), 188 (2020).</li><li>Kumar, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mosquito+Innate+Immunity.">Mosquito Innate Immunity.</a> Insects. 9 (3), (2018).</li><li>Franz, A. W., Kantor, A. M., Passarelli, A. L., Clem, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+Barriers+to+Arbovirus+Infection+in+Mosquitoes.">Tissue Barriers to Arbovirus Infection in Mosquitoes.</a> Viruses. 7 (7), 3741-3767 (2015).</li><li>Xia, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+Ebinur+Lake+Virus+and+Its+Human+Seroprevalence+at+the+China-Kazakhstan+Border.">Characterization of Ebinur Lake Virus and Its Human Seroprevalence at the China-Kazakhstan Border.</a> Frontiers in Microbiology. 10, (2020).</li><li>Baer, A., Kehn-Hall, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Viral+Concentration+Determination+Through+Plaque+Assays:+Using+Traditional+and+Novel+Overlay+Systems.">Viral Concentration Determination Through Plaque Assays: Using Traditional and Novel Overlay Systems.</a> Jove-Journal of Visualized Experiments. (93), e52065 (2014).</li><li>Xu, M. Y., Liu, S. Q., Deng, C. L., Zhang, Q. Y., Zhang, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detection+of+Zika+virus+by+SYBR+green+one-step+real-time+RT-PCR.">Detection of Zika virus by SYBR green one-step real-time RT-PCR.</a> Journal of Virological Methods. 236, 93-97 (2016).</li><li>Yang, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vector+competence+and+transcriptional+response+of+Aedes+aegypti+for+Ebinur+Lake+virus,+a+newly+mosquito-borne+orthobunyavirus.">Vector competence and transcriptional response of Aedes aegypti for Ebinur Lake virus, a newly mosquito-borne orthobunyavirus.</a> bioRxiv. , (2022).</li><li>Britton, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory-acquired+dengue+virus+infection--a+case+report.">Laboratory-acquired dengue virus infection--a case report.</a> PLOS Neglected Tropical Diseases. 5 (11), 1324 (2011).</li><li>Weger-Lucarelli, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vector+Competence+of+American+Mosquitoes+for+Three+Strains+of+Zika+Virus.">Vector Competence of American Mosquitoes for Three Strains of Zika Virus.</a> PLOS Neglected Tropical Diseases. 10 (10), 0005101 (2016).</li><li>Elizondo-Quiroga, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vector+competence+of+Aedes+aegypti+and+Culex+quinquefasciatus+from+the+metropolitan+area+of+Guadalajara,+Jalisco,+Mexico+for+Zika+virus.">Vector competence of Aedes aegypti and Culex quinquefasciatus from the metropolitan area of Guadalajara, Jalisco, Mexico for Zika virus.</a> Scientific reports. 9 (1), 16955 (2019).</li></ol>

The goal of this method was to provide a comprehensive risk assessment of one mosquito-borne virus by evaluating vector competence through oral feeding and intrathoracic inoculation.
In the oral-feeding experiment, engorged-mosquitoes need to be picked out and transferred to a new container, posing a severe risk to the operators. The reason for this is because any mosquito, including uninfected mosquitoes, might be a source of infection19. Consequently, mosquitoes must ...

Mosquito-borne viruses (MBVs), a heterogeneous group of RNA viruses, can persist in mosquito vectors and subsequently spread to vertebrate hosts1. The clinically important MBVs are majorly distributed in four virus families, namely Flaviviridae, Togaviridae, Reoviridae, and Peribunyavividae2,3. In recent decades, these viruses have been reported all across the globe, causing public health issues. As one of the most well-known MBVs, Dengue virus (DENV) has become the most prevalent emerging or re-emerging arbovirus in over 100 countries during the last 20 years4. Since the discovery of Zika virus (ZIKV) inland, almost all tropical and subtropical countries and territories of the continent have reported human ZIKV infections5. In order to assess the risk of virus transmission, numerous studies in recent years have focused on mosquito vector competence for these viruses6,7. As a result, it is critical to effectively prevent and control vector-borne diseases.
Aedes aegypti (Ae. aegypti), one of the most easily reared mosquitoes in the laboratory, is an important vector of DENV, ZIKV, Chikungunya virus (CHIKV), and yellow fever virus (YFV)8. For a long time, Ae. aegypti was solely found in the African continent and in Southeast Asia, but in recent years it has colonized nearly all continents9. Furthermore, the global abundance of Ae. aegypti has been continuously growing, with an estimated 20% increase by the end of the century10. From 2004 to 2009 in China, there was an evident increase in Ae. aegypti vector competence for DENV due to higher day-to-day temperatures11. The status of Ae. aegypti as the pathogenic vector has significantly risen in China. Consequently, to address these challenges, it is necessary to investigate the vector competence of Ae. aegypti's to transmit viruses.
As a haematophagous arthropod, the female mosquito pierces the skin of a vertebrate host and feeds on the blood. Mosquitoes do occasionally acquire viruses from virus-infected hosts and then transfer the viruses to a new host. As such, to determine vector competence, mosquitoes are fed an artificial bloodmeal containing arboviruses through a feeding system in the laboratory setting12. Individual mosquitoes are separated into heads, bodies, and saliva secretions several days after infection. To measure virus infection, dissemination, and transmission rates, virus titers have been detected by quantitative reverse-transcription PCR (qRT-PCR) or plaque assay. However, not all mosquitoes develop midgut infections and the capacity to transfer a virus to the next host following blood feeding. It is linked with mosquitoes' physiological barriers, which prevent pathogens from penetrating the body and play a vital role in their innate immunity13. The midgut barriers, particularly the midgut infection barrier (MIB) and midgut escape barrier (MEB), influence whether the virus could infect the vector systemically and the efficiency with which it spreads. It obstructs the analysis of other tissues' infection, such as salivary glands which also exhibit salivary gland infection and escape barriers13,14. To better characterize the infection of midguts and salivary glands in the vector, a detailed protocol for oral feeding and intrathoracic inoculation of arbovirus in Ae. aegypti is presented herein. This protocol might be applied to additional arbovirus infections in a variety of mosquito vectors, such as DENV and ZIKV infection in Aedes spp., and could prove to be a practicable procedure.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Aedes aegypti&#160;</td>
			<td></td>
			<td></td>
			<td>Rockefeller strain</td>
		</tr>
		<tr>
			<td>Automated nucleic acid extraction system&#160;</td>
			<td>NanoMagBio</td>
			<td>S-48</td>
			<td></td>
		</tr>
		<tr>
			<td>BHK-21 cells</td>
			<td>National Virus Resource Center, Wuhan Institute of Virology</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Buckets</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>C6/36 cells&#160;</td>
			<td>National Virus Resource Center, Wuhan Institute of Virology</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Carbon dioxide spray gun&#160;</td>
			<td>wuhan Yihong</td>
			<td>YHDFPCO2</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifugal machine</td>
			<td>Himac&#160;</td>
			<td>CF16RN</td>
			<td></td>
		</tr>
		<tr>
			<td>CFX96 Touch Real-Time PCR Detection System&#160;</td>
			<td>Bio-Rad</td>
			<td>CFX96 Touch</td>
			<td></td>
		</tr>
		<tr>
			<td>Ebinur Lake virus</td>
			<td></td>
			<td></td>
			<td>Cu20-XJ isolation</td>
		</tr>
		<tr>
			<td>Formaldehyde&#160;</td>
			<td>Wuhan Baiqiandu</td>
			<td>B0003</td>
			<td></td>
		</tr>
		<tr>
			<td>Glove box&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Hushi</td>
			<td>10010518</td>
			<td></td>
		</tr>
		<tr>
			<td>Immersion oil&#160;</td>
			<td>Cargille</td>
			<td>16908-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Insect incubator</td>
			<td>Memmert</td>
			<td>HPP750T7</td>
			<td></td>
		</tr>
		<tr>
			<td>Low Temperature Tissue Homogenizer Grinding Machine&#160;</td>
			<td>Servicebio</td>
			<td>KZ-III-F</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic Virus Genome Extraction Kit</td>
			<td>NanoMagBio</td>
			<td>NMG0966-16</td>
			<td></td>
		</tr>
		<tr>
			<td>mesh cages (30 x 30 x 30 cm)</td>
			<td>Huayu</td>
			<td>HY-35</td>
			<td></td>
		</tr>
		<tr>
			<td>methylcellulose</td>
			<td>Calbiochem</td>
			<td>17851</td>
			<td></td>
		</tr>
		<tr>
			<td>mice feedstuff powder&#160;</td>
			<td>BESSN</td>
			<td>BS018</td>
			<td></td>
		</tr>
		<tr>
			<td>Microelectrode Puller</td>
			<td>WPI</td>
			<td>PUL-1000</td>
			<td>PUL-1000&#160;is a microprocessor controlled horizontal puller for making glass micropipettes or microelectrodes used in intracellular recording, patch clamp studies, microperfusion or microinjection.</td>
		</tr>
		<tr>
			<td>Mosquito net meshes&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nanoject III Programmable Nanoliter Injector</td>
			<td>Drummond</td>
			<td>3-000-207</td>
			<td></td>
		</tr>
		<tr>
			<td>One Step TB Green PrimeScript PLUS RT-PCR Kit&#160;</td>
			<td>Takara</td>
			<td>RR096A</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS, pH 7.4</td>
			<td>Gibco</td>
			<td>C10010500BT</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/streptomycin</td>
			<td>Gibco</td>
			<td>151140-122</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dishes&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Plastic cupes (7 oz)&#160;</td>
			<td>Hubei Duoanduo</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Plastic cups (24 oz)&#160;</td>
			<td>Anhui shangji</td>
			<td>PET32-Tub-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Plastic disposable droppers</td>
			<td>Biosharp</td>
			<td>BS-XG-O3L-NS</td>
			<td></td>
		</tr>
		<tr>
			<td>Refrigerator (-80 &#176;C)</td>
			<td>sanyo</td>
			<td>MDF-U54V</td>
			<td></td>
		</tr>
		<tr>
			<td>Replacement Glass Capillaries</td>
			<td>Drummond</td>
			<td>3-000-203-G/X</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI medium 1640&#160;</td>
			<td>Gibco</td>
			<td>C11875500BT</td>
			<td></td>
		</tr>
		<tr>
			<td>Screw cap storage tubes (2 mL )</td>
			<td>biofil</td>
			<td>&#160;FCT010005</td>
			<td></td>
		</tr>
		<tr>
			<td>Shallow dishes&#160;</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sponge</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile defibrillated horse blood</td>
			<td>Wuhan Purity Biotechnology</td>
			<td>CDHXB413</td>
			<td></td>
		</tr>
		<tr>
			<td>T75 culture flask</td>
			<td>Corning</td>
			<td>430829</td>
			<td></td>
		</tr>
		<tr>
			<td>The artificial mosquito feeding system&#160;</td>
			<td>Hemotek</td>
			<td>Hemotek PS6</td>
			<td></td>
		</tr>
		<tr>
			<td>The dissecting microscope&#160;</td>
			<td>ZEISS</td>
			<td>&#160;stemi508</td>
			<td></td>
		</tr>
		<tr>
			<td>The ice plates</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>The mosquito absorbing machine&#160;</td>
			<td>Ningbo Bangning</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>The pipette tips&#160;</td>
			<td>Axygen</td>
			<td>TF</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin-EDTA (0.25%)</td>
			<td>Gibco</td>
			<td>25200056</td>
			<td></td>
		</tr>
		<tr>
			<td>Tweezers</td>
			<td>Dumont</td>
			<td>0203-5-PO</td>
			<td></td>
		</tr>
	</tbody>
</table>

experimental viral infection in adult mosquitoes by oral feeding and microinjection

Mosquito-borne viruses (MBVs), which are infectious pathogens to vertebrates, are spread by many mosquito species, posing a severe threat to public health. Once ingested, the viruses must overcome the mosquito midgut barrier to reach the hemolymph, from where they might potentially spread to the salivary glands. When a mosquito bites, these viruses are spread to new vertebrate hosts. Similarly, the mosquito may pick up different viruses. In general, only a tiny portion of viruses may enter the salivary glands via the gut. The transmission efficiency of these viruses to the glands is be affected by the two physical barriers found in different mosquito species: midgut barriers and salivary glands barriers. This protocol presents a method for virus detection in salivary glands of Aedes aegypti&#39;s&#160;following oral feeding and intrathoracic injection infection. Furthermore, determining whether the guts and/or salivary glands hinder viral spread can aid in the risk assessments of MBVs transmitted by Aedes aegypti.

To examine EBIV distribution in the infected mosquitoes via artificial blood feeding (the viral final titer was 6.4 x 106 PFU/mL) and intrathoracic injection (the viral dose was 340 PFU), viral RNAs in saliva, heads, and guts of the mosquitoes at 10 days post infection (dpi) were determined.
For Ae. aegypti, virus titer of EBIV in the guts, heads, and saliva of the intrathoracically inoculated female mosquitoes were much higher than that in the oral-infected female...

Watch this Scientific Journal Video about Experimental Viral Infection in Adult Mosquitoes by Oral Feeding and Microinjection at JoVE.com

Experimental Viral Infection in Adult Mosquitoes by Oral Feeding and Microinjection

This methodology, which included oral feeding and intrathoracic injection infection, could effectively assess the influence of midgut and/or salivary gland barriers on arbovirus infection.

Mosquito-borne viruses (MBVs), which are infectious pathogens to vertebrates, are spread by many mosquito species, posing a severe threat to public ...

This protocol can determine whether the guts and the thyroid glands hinder viral spread and can aid in the risk assessments of mosquito-borne viruses transmitted by Aedes aegypti. Our protocol included two infection methods, oral feeding and the intrathoracic injection, which could effectively assess the vector competence of arbovirus. This protocol might be applied to additional arbovirus infections in a variety of mosquito vectors, such as Dengue virus and Zika virus infection in Aedes, and could prove to be a practicable procedure.Demonstrating the procedure will be Fei Wang, a research assistant from my lab. To perform artificial feeding using the artificial mosquito feeding system, cut the collagen membranes to the appropriate size, and secure them to the reservoirs with the O-rings. Add three milliliters of the virus-blood mixture to the reservoirs, and seal the reservoirs using plastic plugs to prevent leakages.Put the plastic cups containing mosquitoes into the glove box. Screw the sealed reservoirs into the FU1 feeder, and put one reservoir on one cup. Turn on the power unit, and feed the mosquitoes for one hour.After feeding, anesthetize the mosquitoes with ice for several seconds until they faint. Pour the anesthetized mosquitoes into a Petri dish placed on ice, and cover the lid quickly. Pick engorged female mosquitoes with forceps, and transfer them to new plastic cups at 50 female mosquitoes per cup.Wrap the cup with a cut mosquito net mesh, and cover it with a lid with a hole in the middle. Cut the sponge into small pieces, and put them on the cups. Add 8%glucose solution onto the sponge using a plastic disposable dropper.Place the cups containing female mosquitoes in the incubator at 27 degrees Celsius at 80%humidity for 10 days. Replace a new glucose-saturated sponge every 72 hours. For intrathoracic inoculation, prepare female mosquitoes as described in the text manuscript.To prepare the infectious virus dilution, remove the virus stock from the 80 degrees Celsius freezer, and thaw them on ice. Dilute virus stock at a 100-nanoliter virus dilution containing 100 to 500 plaque-forming units virus with RPMI 1640 medium containing 10%FBS and 1%penicillin-streptomycin. Place the virus dilution on ice.Next, prepare the microinjection needles using a Puller 1000 with the parameters in the needle puller program set as heat index to 450, force in g to 110, distance in millimeter to one, and delay in seconds to zero. Cut the tip of a pulled needle with tweezers under a dissecting microscope at 16x magnification. Backfill the needle with mineral oil through a disposable sterile syringe.Attach the needle into the injector following the instructions on the machine. Insert the needle carefully into a tube containing an infectious virus dilution. Then, press the Fill button to fill approximately four microliters of virus dilution into the needle.Once the needle is filled, do not touch or damage the needle. Pick approximately 50 female anesthetized mosquitoes with tweezers, and put them on a ice plate. Place the plate under the injector, and insert the needle into the thoracic cavity of the mosquito under a dissecting microscope.Set the injection volume to 100 nanoliters and the rate to 50 nanoliters per second. Press the Inject button to let the virus solution flow into the mosquito. Upon successful injection, the abdomen bulges slightly.Put the infected mosquito into a new plastic cup placed on ice. When the number of infected mosquitoes is enough, wrap the cup with a cut mosquito net mesh and cover it with the lid. To collect saliva from the infected female mosquitoes, pour the anesthetized mosquitoes into a Petri dish placed on ice, and close the lid quickly.Place 10-microliter pipette tips filled with immersion oil side by side on the rubber mud. Pick the female mosquitoes with tweezers, and put them on an ice plate. Remove their legs and wings with tweezers.Place the mouthpart of one mosquito on each pipette tip to collect the saliva as secreted into the oil by the mosquitoes at room temperature. After 45 to 60 minutes, place the pipette tips in 1.5-milliliter tubes containing 200 microliters of virus diluent medium. Centrifuge the tubes at 5, 000 g for five minutes at four degrees Celsius to expel saliva into the tubes.Store the saliva-containing tubes at 80 degrees Celsius for subsequent determination of transmission rates. After saliva collection, dissect the infected female mosquitoes. Using tweezers, cut the heads of the mosquitoes, and place each head into an individual tube containing 200 microliters of RPMI 1640 medium.Grab the thorax with a tweezer. Then, grab the penultimate segment of the abdomen with another tweezer, and pull the gut out. Clean the gut for any stray tissue and organs.Wash the gut with PBS, and place each gut into an individual tube containing 200 microliters of RPMI 1640 medium. Store these tubes at 80 degrees Celsius for subsequent determination of the virus dissemination and infection rate. In this representative analysis, viral RNAs in the gut, head, and saliva of the female mosquitoes at 10 days post-infection were determined.The virus titer of Ebinur Lake virus in the guts, heads, and saliva of the intrathoracically inoculated mosquitoes were higher than that in the oral-infected mosquitoes. The infection and dissemination rate for the intrathoracically inoculated mosquitoes was 100%and for the oral-infected mosquitoes was found to be 70%and 38.1%respectively. The transmission rate for the intrathoracically inoculated mosquitoes reached up to 90%but for the oral-infected mosquitoes was only 4.8%The engorged female mosquitoes were picked to maintain consistency, as the feeding amount affects the viral content.

experimental-viral-infection-adult-mosquitoes-oral-feeding

Research

JoVE Journal

Immunology and Infection

1.8K visualizações.  Chinese Academy of Sciences. Esse protocolo pode determinar se o intestino e as glândulas tireoides impedem a disseminação viral e pode auxiliar nas avaliações de risco de vírus transmitidos por mosquitos transmitidos pelo Aedes aegypti. Nosso protocolo incluiu dois métodos de infecção, a alimentação por via oral e a injeção intratorácica, que puderam avaliar efetivamente a competência vetorial das arboviroses. Este protocolo pode ser aplicado a infecções adicionais por arbovírus em uma variedade de mos...