scholarly journals Estimating the effects of variation in viremia on mosquito susceptibility, infectiousness, and R0 of Zika in Aedes aegypti

2017 ◽  
Author(s):  
Blanka Tesla ◽  
Leah R. Demakovsky ◽  
Hannah S. Packiam ◽  
Erin A. Mordecai ◽  
Américo D. Rodríguez ◽  
...  

AbstractZika virus (ZIKV) is an arbovirus primarily transmitted by Aedes mosquitoes. Like most viral infections, ZIKV viremia varies over several orders of magnitude, with unknown consequences for transmission. To determine the effect of viral concentration on ZIKV transmission risk, we exposed field-derived Ae. aegypti mosquitoes to four doses (103, 104, 105, 106 PFU/mL) representative of potential variation in the field. We demonstrate that increasing ZIKV dose in the blood-meal significantly increases the probability of mosquitoes becoming infected and infectious, as well as the rate at which virus spreads to the saliva, but found no effect on dissemination efficiency or mosquito mortality. We also demonstrate that determining infection using RT-qPCR approaches rather than plaque assays potentially over-estimates key pathogen parameters, including the time at which mosquitoes become infectious and viral burden. Finally, using these data to parameterize an R0 model, we demonstrate that variation in viremia substantially affects transmission risk.


2019 ◽  
Vol 57 (3) ◽  
pp. 957-961
Author(s):  
Kyran M Staunton ◽  
Barukh B Rohde ◽  
Michael Townsend ◽  
Jianyi Liu ◽  
Mark Desnoyer ◽  
...  

Abstract Aedes aegypti (Linnaeus), the primary vectors of the arboviruses dengue virus and Zika virus, continue to expand their global distributions. In efforts to better control such species, several mosquito control programs are investigating the efficacy of rearing and releasing millions of altered male Aedes throughout landscapes to reduce populations and disease transmission risk. Unfortunately, little is known about Ae. aegypti, especially male, dispersal behaviors within urban habitats. We deployed Sound-producing Gravid Aedes Traps (SGATs) in Cairns, northern Australia, to investigate male Ae. aegypti attraction to various oviposition container configurations. The traps were arranged to include: 1) water only, 2) organically infused water, 3) infused water and L3 larvae, 4) infused water and a human-scented lure, and lastly 5) no water or olfactory attractant (dry). Our data suggest that males were more attracted to SGATs representing active larval sites than potential larval sites, but were equally attracted to dry SGATs relative to those containing water and/or infusion. Additionally, we found that female Ae. aegypti were equally attracted to wet SGATs, with or without infusion, but not dry ones. These results suggest that male Ae. aegypti within northern Australia are more attracted to active larval sites and equally attracted to dry containers as wet or infused ones. Additionally, female Ae. aegypti are unlikely to enter dry containers. Such findings contribute to our understanding of potentially attractive features for local and released Ae. aegypti throughout the northern Australian urban landscape.



Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 177 ◽  
Author(s):  
Tereza Magalhaes ◽  
Alexis Robison ◽  
Michael Young ◽  
William Black ◽  
Brian Foy ◽  
...  

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.



PLoS ONE ◽  
2018 ◽  
Vol 13 (7) ◽  
pp. e0200766 ◽  
Author(s):  
Martha Thieme Petersen ◽  
Isabella Dias da Silveira ◽  
Aline Tátila-Ferreira ◽  
Mariana Rocha David ◽  
Thais Chouin-Carneiro ◽  
...  


2021 ◽  
Vol 15 (11) ◽  
pp. e0010003
Author(s):  
Christie S. Herd ◽  
DeAna G. Grant ◽  
Jingyi Lin ◽  
Alexander W. E. Franz

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.



2009 ◽  
Vol 24 ◽  
pp. 156 ◽  
Author(s):  
Ishan Gautam ◽  
Megh Nath Dhimal ◽  
Shambhu Raj Shrestha ◽  
Anand Shova Tamrakar

Aedes aegypti is the primary vector for the transmission of Dengue Fever (DF)/Dengue Haemorrhagic Fever (DHF). Entomological investigations on breeding habitats and larval prevalence of mosquitoes Aedes aegypti (L.) and Ae. albopictus (Skuse) were conducted from April to June 2009 in Kathmandu district, Nepal. Different water-filled containers were examined for the presence or absence of Aedes larvae. Larval survey techniques were used to obtain the House Index (HI), Container Index (CI) and Breteau Index (BI). The over all HI, CI and BI for Aedes aegypti were 6.25, 4.83, 9.37 and for Aedes albopictus were 6.25, 3.22 and 6.25 respectively. It was also observed that discarded tires lying outdoors were the preferred breeding habitats. No breeding was observed in other containers in April and May during this three months survey. Herewith, we report the first collection and identification of Aedes aegypti in Kathmandu during June, 2009. Indeed, this finding constitutes the first record from the capital of Nepal within the urban agglomeration of Basundhara and Gongabu-Balaju area.Therefore, DF/DHF transmission risk may occur locally if imported cases are introduced.  Key Words: Aedes aegypti; Ae. albopictus;  Kathmandu; First record; Dengue Fever.Journal of Natural History MuseumVol 24, 2009.Page:



2020 ◽  
Vol 42 (3) ◽  
Author(s):  
André Emanuel Dantas Mercês ◽  
Angela de Souza Cajuhi ◽  
Lorena Conceição Souza dos Santos ◽  
Rudval Souza da Silva ◽  
Cleuma Sueli Santos Suto ◽  
...  

O Zika vírus é um arbovírus transmitido pela picada dos mosquitos Aedes aegypti e Aedes albopictus infectados e apresentam como principais manifestações clínicas: febre aguda, exantema, prurido e conjuntivite. Em 2015 causou uma epidemia no Brasil, desencadeando casos de microcefalia em bebês cujas gestantes tiveram a febre da Zika. O Nordeste notificou o maior número de casos. Objetivou-se identificar, a partir de uma revisão integrativa, a relação entre a febre da Zika e a microcefalia. Trata-se de revisão integrativa, realizada a partir de buscas desenvolvidas nas bases de dados da Biblioteca Virtual em Saúde (BVS) e da Scientific Electronic Library Online (SciELO) com publicações dos anos de 2015 e 2016, idiomas português e inglês. Foram encontradas 191 publicações, as quais passaram por um processo de leitura e análise quanto ao atendimento do objetivo e aplicação dos critérios de inclusão. Restaram oito publicações que integraram o corpus desta revisão. Os resultados apontam para uma relação de causa e efeito entre o contato das gestantes com o Zika vírus e o desenvolvimento de microcefalia em seus bebês. Necessita-se de maiores evidências que demonstrem os reais fatores envolvidos nesse processo, como os genéticos, ambientais e até mesmo interferência de outras infecções. Palavras-chave: Zika vírus. Microcefalia. Aplicações da epidemiologia.



Author(s):  
Rebecca A Zimler ◽  
Donald A Yee ◽  
Barry W Alto

Abstract Recurrence of local transmission of Zika virus in Puerto Rico is a major public health risk to the United States, where mosquitoes Aedes aegypti (Linnaeus) and Aedes mediovittatus (Coquillett) are abundant. To determine the extent to which Ae. mediovittatus are capable of transmitting Zika virus and the influence of viremia, we evaluated infection and transmission in Ae. mediovittatus and Ae. aegypti from Puerto Rico using serial dilutions of infectious blood. Higher doses of infectious blood resulted in greater infection rates in both mosquitoes. Aedes aegypti females were up to twice as susceptible to infection than Ae. mediovittatus, indicating a more effective midgut infection barrier in the latter mosquito species. Aedes aegypti exhibited higher disseminated infection (40–95%) than Ae. mediovittatus (<5%), suggesting a substantial midgut escape barrier in Ae. mediovittatus. For Ae. aegypti, transmission rates were low over a range of doses of Zika virus ingested, suggesting substantial salivary gland barriers.



2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Lourdes G. Talavera-Aguilar ◽  
Reyes A. Murrieta ◽  
Sungmin Kiem ◽  
Rosa C. Cetina-Trejo ◽  
Carlos M. Baak-Baak ◽  
...  

Abstract Background Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) with an urban transmission cycle that primarily involves humans and Aedes aegypti. Evidence suggests that the evolution of some arboviruses is constrained by their dependency on alternating between disparate (vertebrate and invertebrate) hosts. The goals of this study are to compare the genetic changes that occur in ZIKV after serial passaging in mosquito or vertebrate cell lines or alternate passaging in both cell types and to compare the replication, dissemination, and transmission efficiencies of the cell culture-derived viruses in Ae. aegypti. Methods An isolate of ZIKV originally acquired from a febrile patient in Yucatan, Mexico, was serially passaged six times in African green monkey kidney (Vero) cells or Aedes albopictus (C6/36) cells or both cell types by alternating passage. A colony of Ae. aegypti from Yucatan was established, and mosquitoes were challenged with the cell-adapted viruses. Midguts, Malpighian tubules, ovaries, salivary glands, wings/legs and saliva were collected at various times after challenge and tested for evidence of virus infection. Results Genome sequencing revealed the presence of two non-synonymous substitutions in the premembrane and NS1 regions of the mosquito cell-adapted virus and two non-synonymous substitutions in the capsid and NS2A regions of both the vertebrate cell-adapted and alternate-passaged viruses. Additional genetic changes were identified by intrahost variant frequency analysis. Virus maintained by continuous C6/36 cell passage was significantly more infectious in Ae. aegypti than viruses maintained by alternating passage and consecutive Vero cell passage. Conclusions Mosquito cell-adapted ZIKV displayed greater in vivo fitness in Ae. aegypti compared to the other viruses, indicating that obligate cycling between disparate hosts carries a fitness cost. These data increase our understanding of the factors that drive ZIKV adaptation and evolution and underscore the important need to consider the in vivo passage histories of flaviviruses to be evaluated in vector competence studies. Graphic abstract "Image missing"



2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Rommel J. Gestuveo ◽  
Jamie Royle ◽  
Claire L. Donald ◽  
Douglas J. Lamont ◽  
Edward C. Hutchinson ◽  
...  

AbstractThe escalating global prevalence of arboviral diseases emphasizes the need to improve our understanding of their biology. Research in this area has been hindered by the lack of molecular tools for studying virus-mosquito interactions. Here, we develop an Aedes aegypti cell line which stably expresses Zika virus (ZIKV) capsid proteins in order to study virus-vector protein-protein interactions through quantitative label-free proteomics. We identify 157 interactors and show that eight have potentially pro-viral activity during ZIKV infection in mosquito cells. Notably, silencing of transitional endoplasmic reticulum protein TER94 prevents ZIKV capsid degradation and significantly reduces viral replication. Similar results are observed if the TER94 ortholog (VCP) functioning is blocked with inhibitors in human cells. In addition, we show that an E3 ubiquitin-protein ligase, UBR5, mediates the interaction between TER94 and ZIKV capsid. Our study demonstrates a pro-viral function for TER94/VCP during ZIKV infection that is conserved between human and mosquito cells.



Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 774
Author(s):  
Chengfeng Gao ◽  
Chunxia Wen ◽  
Zhifeng Li ◽  
Shuhan Lin ◽  
Shu Gao ◽  
...  

Viral infections are one of the leading causes in human mortality and disease. Broad-spectrum antiviral drugs are a powerful weapon against new and re-emerging viruses. However, viral resistance to existing broad-spectrum antivirals remains a challenge, which demands development of new broad-spectrum therapeutics. In this report, we showed that fludarabine, a fluorinated purine analogue, effectively inhibited infection of RNA viruses, including Zika virus, Severe fever with thrombocytopenia syndrome virus, and Enterovirus A71, with all IC50 values below 1 μM in Vero, BHK21, U251 MG, and HMC3 cells. We observed that fludarabine has shown cytotoxicity to these cells only at high doses indicating it could be safe for future clinical use if approved. In conclusion, this study suggests that fludarabine could be developed as a potential broad-spectrum anti-RNA virus therapeutic agent.



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