Starvation at the larval stage increases the vector competence of Aedes aegypti females for Zika virus

Aedes aegypti is the primary vector of Zika virus (ZIKV), a flavivirus which typically presents itself as febrile-like symptoms in humans but can also cause neurological and pregnancy complications. The transmission cycle of mosquito-borne arboviruses such as ZIKV requires that various key tissues in the female mosquito including the salivary glands get productively infected with the virus before the mosquito can transmit the virus to another vertebrate host. Following ingestion of a viremic blood-meal from a vertebrate, ZIKV initially infects the midgut epithelium before exiting the midgut after blood-meal digestion to disseminate to secondary tissues including the salivary glands. Here we investigated whether smaller Ae. aegypti females resulting from food deprivation as larvae exhibited an altered vector competence for blood-meal acquired ZIKV relative to larger mosquitoes. Midguts from small ‘Starve’ and large ‘Control’ Ae. aegypti were dissected to visualize by transmission electron microscopy (TEM) the midgut basal lamina (BL) as physical evidence for the midgut escape barrier showing Starve mosquitoes with a significantly thinner midgut BL than Control mosquitoes at two timepoints. ZIKV replication was inhibited in Starve mosquitoes following intrathoracic injection of virus, however, Starve mosquitoes exhibited a significantly higher midgut escape and population dissemination rate at 9 days post-infection (dpi) via blood-meal, with more virus present in saliva and head tissue than Control by 10 dpi and 14 dpi, respectively. These results indicate that Ae. aegypti developing under stressful conditions potentially exhibit higher midgut infection and dissemination rates for ZIKV as adults, Thus, variation in food intake as larvae is potentially a source for variable vector competence levels of the emerged adults for the virus.

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Sequential Infection of Aedes aegypti Mosquitoes with Chikungunya Virus and Zika Virus Enhances Early Zika Virus Transmission

Insects ◽

10.3390/insects9040177 ◽

2018 ◽

Vol 9 (4) ◽

pp. 177 ◽

Cited By ~ 12

Author(s):

Tereza Magalhaes ◽

Alexis Robison ◽

Michael Young ◽

William Black ◽

Brian Foy ◽

...

Keyword(s):

Aedes Aegypti ◽

Blood Meal ◽

Zika Virus ◽

Chikungunya Virus ◽

Vector Competence ◽

Virus Transmission ◽

Mosquito Vector ◽

Molecular Aspects ◽

Virus Interactions ◽

Sequential Infection

In urban settings, chikungunya, Zika, and dengue viruses are transmitted by Aedes aegypti mosquitoes. Since these viruses co-circulate in several regions, coinfection in humans and vectors may occur, and human coinfections have been frequently reported. Yet, little is known about the molecular aspects of virus interactions within hosts and how they contribute to arbovirus transmission dynamics. We have previously shown that Aedes aegypti exposed to chikungunya and Zika viruses in the same blood meal can become coinfected and transmit both viruses simultaneously. However, mosquitoes may also become coinfected by multiple, sequential feeds on single infected hosts. Therefore, we tested whether sequential infection with chikungunya and Zika viruses impacts mosquito vector competence. We exposed Ae. aegypti mosquitoes first to one virus and 7 days later to the other virus and compared infection, dissemination, and transmission rates between sequentially and single infected groups. We found that coinfection rates were high after sequential exposure and that mosquitoes were able to co-transmit both viruses. Surprisingly, chikungunya virus coinfection enhanced Zika virus transmission 7 days after the second blood meal. Our data demonstrate heterologous arbovirus synergism within mosquitoes, by unknown mechanisms, leading to enhancement of transmission under certain conditions.

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Vector competence and transovarial transmission of two Aedes aegypti strains to Zika virus

Emerging Microbes & Infections ◽

10.1038/emi.2017.8 ◽

2017 ◽

Vol 6 (1) ◽

pp. 1-7 ◽

Cited By ~ 17

Author(s):

Chun-xiao Li ◽

Xiao-xia Guo ◽

Yong-qiang Deng ◽

Dan Xing ◽

Ai-juan Sun ◽

...

Keyword(s):

Aedes Aegypti ◽

Zika Virus ◽

Vector Competence ◽

Transovarial Transmission

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Vector Competence of French Polynesian Aedes aegypti and Aedes polynesiensis for Zika Virus

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0005024 ◽

2016 ◽

Vol 10 (9) ◽

pp. e0005024 ◽

Cited By ~ 47

Author(s):

Vaea Richard ◽

Tuterarii Paoaafaite ◽

Van-Mai Cao-Lormeau

Keyword(s):

Aedes Aegypti ◽

Zika Virus ◽

Vector Competence ◽

Aedes Polynesiensis

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Zika mosquito vectors: the jury is still out

F1000Research ◽

10.12688/f1000research.9839.1 ◽

2016 ◽

Vol 5 ◽

pp. 2546 ◽

Cited By ~ 4

Author(s):

Walter S. Leal

Keyword(s):

Aedes Aegypti ◽

Yellow Fever ◽

Culex Quinquefasciatus ◽

Zika Virus ◽

Field Data ◽

Vector Competence ◽

Sexual Transmission ◽

Mosquito Vectors ◽

Yellow Fever Mosquito ◽

The Common

After a 40-year hiatus, the International Congress of Entomology (ICE 2016) convened in Orlando, Florida (September 25-30, 2016). One of the symposia at ICE 2016, the Zika Symposium, covered multiple aspects of the Zika epidemic, including epidemiology, sexual transmission, genetic tools for reducing transmission, and particularly vector competence. While there was a consensus among participants that the yellow fever mosquito, Aedes aegypti, is a vector of the Zika virus, there is growing evidence indicating that the range of mosquito vectors might be wider than anticipated. In particular, three independent groups from Canada, China, and Brazil presented and discussed laboratory and field data strongly suggesting that the southern house mosquito, Culex quinquefasciatus, also known as the common mosquito, is highly likely to be a vector in certain environments.

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Serine hydroxymethyltransferase controls blood-meal digestion in the midgut of Aedes aegypti mosquitoes

Parasites & Vectors ◽

10.1186/s13071-019-3714-2 ◽

2019 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Xuemei Li ◽

Jinyu Yang ◽

Qian Pu ◽

Xinyue Peng ◽

Lili Xu ◽

...

Keyword(s):

Aedes Aegypti ◽

Blood Meal ◽

Digestive Enzymes ◽

Egg Production ◽

Sequence Similarity ◽

Mrna Level ◽

Serine Hydroxymethyltransferase ◽

Blood Protein ◽

Transcriptional Expression ◽

Blood Meal Digestion

Abstract Background Female Aedes aegypti mosquitoes are vectors of arboviruses that cause diverse diseases of public health significance. Blood protein digestion by midgut proteases provides anautogenous mosquitoes with the nutrients essential for oocyte maturation and egg production. Midgut-specific miR-1174 affects the functions of the midgut through its target gene serine hydroxymethyltransferase (SHMT). However, less is known about SHMT-regulated processes in blood digestion by mosquitoes. Methods RNAi of SHMT was realized by injection of the double-stranded RNA at 16 h post-eclosion. The expression of SHMT at mRNA level and protein level was assayed by real-time PCR and Western blotting, respectively. Statistical analyses were performed with GraphPad7 using Student’s t-test. Results Here, we confirmed that digestion of blood was inhibited in SHMT RNAi-silenced female A. aegypti mosquitoes. Evidence is also presented that all SHMT-depleted female mosquitoes lost their flight ability and died within 48 h of a blood meal. Furthermore, most examined digestive enzymes responded differently in their transcriptional expression to RNAi depletion of SHMT, with some downregulated, some upregulated and some remaining stable. Phylogenetic analysis showed that transcriptional expression responses to SHMT silence were largely unrelated to the sequence similarity between these enzymes. Conclusions Overall, this research shows that SHMT was expressed at a low level in the midgut of Aedes aegypti mosquitoes, but blood-meal digestion was inhibited when SHMT was silenced. Transcriptional expressions of different digestive enzymes were affected in response to SHMT depletion, suggesting that SHMT is required for the blood-meal digestion in the midgut and targeting SHMT could provide an effective strategy for vector mosquito population control.

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Vector Competence Analyses on Aedes aegypti Mosquitoes using Zika Virus

Journal of Visualized Experiments ◽

10.3791/61112 ◽

2020 ◽

Author(s):

Sasha R. Azar ◽

Scott C. Weaver

Keyword(s):

Aedes Aegypti ◽

Zika Virus ◽

Vector Competence

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Vector competence of Malaysian Aedes aegypti to Zika virus and impact of sequential arbovirus infections

Acta Tropica ◽

10.1016/j.actatropica.2020.105472 ◽

2020 ◽

Vol 208 ◽

pp. 105472

Author(s):

Nyee Huey Ong ◽

Chong Long Chua ◽

Jonathan Wee Kent Liew ◽

Wan Yusoff Wan Sulaiman ◽

Yoke Fun Chan ◽

...

Keyword(s):

Aedes Aegypti ◽

Zika Virus ◽

Vector Competence

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Low Aedes aegypti Vector Competence for Zika Virus from Viremic Rhesus Macaques

Viruses ◽

10.3390/v12121345 ◽

2020 ◽

Vol 12 (12) ◽

pp. 1345

Author(s):

Rosilainy Surubi Fernandes ◽

Mariana Rocha David ◽

Filipe Vieira Santos De Abreu ◽

Anielly Ferreira-de-Brito ◽

Noemi R. Gardinali ◽

...

Keyword(s):

Viral Load ◽

Aedes Aegypti ◽

Short Duration ◽

Zika Virus ◽

Rhesus Macaques ◽

Vector Competence ◽

Transmission Dynamics ◽

Zikv Infection ◽

Transmission Rates ◽

Time Points

Despite worldwide efforts to understand the transmission dynamics of Zika virus (ZIKV), scanty evaluation has been made on the vector competence of Aedes aegypti fed directly on viremic human and non-human primates (NHPs). We blood-fed Ae. aegypti from two districts in Rio de Janeiro on six ZIKV infected pregnant rhesus macaques at several time points, half of which were treated with Sofosbuvir (SOF). Mosquitoes were analyzed for vector competence after 3, 7 and 14 days of incubation. Although viremia extended up to eight days post monkey inoculation, only mosquitoes fed on the day of the peak of viremia, recorded on day two, became infected. The influence of SOF treatment could not be assessed because the drug was administered just after mosquito feeding on day two. The global infection, dissemination and transmission rates were quite low (4.09%, 1.91% and 0.54%, respectively); no mosquito was infected when viremia was below 1.26 × 105 RNA copies/mL. In conclusion, Ae. aegypti vector competence for ZIKV from macaques is low, likely to be due to low viral load and the short duration of ZIKV viremia in primates suitable for infecting susceptible mosquitoes. If ZIKV infection in human and macaques behaves similarly, transmission of the Zika virus in nature is most strongly affected by vector density.

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Colonized Sabethes cyaneus, a Sylvatic New World Mosquito Species, Shows a Low Vector Competence for Zika Virus Relative to Aedes aegypti

Viruses ◽

10.3390/v10080434 ◽

2018 ◽

Vol 10 (8) ◽

pp. 434 ◽

Cited By ~ 12

Author(s):

Ajit K. Karna ◽

Sasha R. Azar ◽

Jessica A. Plante ◽

Rumei Yun ◽

Nikos Vasilakis ◽

...

Keyword(s):

Aedes Aegypti ◽

Yellow Fever ◽

Zika Virus ◽

New World ◽

Yellow Fever Virus ◽

Vector Competence ◽

Mosquito Species ◽

Sylvatic Cycle ◽

Post Feeding ◽

Body Compartments

The introduction of Zika virus (ZIKV) to the Americas raised concern that the virus would spill back from human transmission, perpetuated by Aedes aegypti, into a sylvatic cycle maintained in wildlife and forest-living mosquitoes. In the Americas, Sabethes species are vectors of sylvatic yellow fever virus (YFV) and are therefore candidate vectors of a sylvatic ZIKV cycle. To test the potential of Sabethes cyaneus to transmit ZIKV, Sa. cyaneus and Ae. aegypti were fed on A129 mice one or two days post-infection (dpi) with a ZIKV isolate from Mexico. Sa. cyaneus were sampled at 3, 4, 5, 7, 14, and 21 days post-feeding (dpf) and Ae. aegypti were sampled at 14 and 21 dpf. ZIKV was quantified in mosquito bodies, legs, and saliva to measure infection, dissemination, and potential transmission, respectively. Of 69 Sa. cyaneus that fed, ZIKV was detected in only one, in all body compartments, at 21 dpf. In contrast, at 14 dpf 100% of 20 Ae. aegypti that fed on mice at 2 dpi were infected and 70% had virus in saliva. These data demonstrate that Sa. cyaneus is a competent vector for ZIKV, albeit much less competent than Ae. aegypti.

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