scholarly journals Evaluating the vector competence of Aedes simpsoni sl from Kenyan coast for Ngari and Bunyamwera viruses

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253955
Author(s):  
James Mutisya ◽  
Michael Kahato ◽  
Francis Mulwa ◽  
Solomon Langat ◽  
Edith Chepkorir ◽  
...  
Keyword(s):  
Blood Meal ◽  
Post Infection ◽  
Vector Competence ◽  
Plaque Assay ◽  
Coastal Region ◽  
Control Plan ◽  
Disseminated Infection ◽  
Vector Population ◽  
Kenyan Coast ◽  
Bunyamwera Virus

Background Bunyamwera(BUNV) and Ngari (NGIV) viruses are arboviruses of medical importance globally, the viruses are endemic in Africa, Aedes(Ae) aegypti and Anopheles(An) gambiae mosquitoes are currently competent vectors for BUNV and NGIV respectively. Both viruses have been isolated from humans and mosquitoes in various ecologies of Kenya. Understanding the risk patterns and spread of the viruses necessitate studies of vector competence in local vector population of Ae. simpsoni sl which is abundant in the coastal region. This study sought to assess the ability of Ae. Simpsoni sl mosquitoes abundant at the Coast of Kenya to transmit these viruses in experimental laboratory experiments. Methods Field collected larvae/pupae of Ae. Simpsoni sl mosquitoes from Rabai, Kilifi County, were reared to adults, the first filial generation (F0) females’ mosquitoes were orally exposed to infectious blood meal with isolates of the viruses using the hemotek membrane feeder. The exposed mosquitoes were incubated under insectary conditions and sampled on day 7, 14 and 21days post infection to determine susceptibility to the virus infection using plaque assay. Results A total of 379 (Bunyamwera virus 255 and Ngari virus 124) Ae. simpsoni sl were orally exposed to infectious blood meal. Overall, the infection rate (IR) for BUNV and NGIV were 2.7 and 0.9% respectively. Dissemination occurred in 5 out 7 mosquitoes with mid-gut infection for Bunyamwera virus and 1 out of 2 mosquitoes with mid-gut infection for Ngari virus. Further, the transmission was observed in 1 out of 5 mosquitoes that had disseminated infection and no transmission was observed for Ngari virus in all days post infection (dpi). Conclusion Our study shows that Ae. simpsoni sl. is a laboratory competent vector for Bunyamwera virus since it was able to transmit the virus through capillary feeding while NGIV infection was restricted to midgut infection and disseminated infection, these finding adds information on the epidemiology of the viruses and vector control plan.

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

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 177 ◽  
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.

scholarly journals Volume and surface changes in vero cell and its nucleus after infection with measles virus: a stereological study

2011 ◽  
Vol 2 (1) ◽  
pp. 18
Author(s):  
Ali Noorafshan ◽  
Mohammad Motamedifar ◽  
Saied Karbalay-Doust
Keyword(s):  
Vero Cell ◽  
Post Infection ◽  
Measles Virus ◽  
Plaque Assay ◽  
Vero Cells ◽  
Uninfected Control ◽  
Mean Cell Volume ◽  
Significant Difference ◽  
Infected Cells ◽  
The Mean

Measles virus has no or indistinctive cytopathic effects (CPE) in cell couture system. Employment of some detecting methods like plaque assay or stereologic experiments, as a method of detecting of viral infection in the cells would be applicable. The aim of this study was investigating the early changes in quantitative parameters of measles virus infected Vero cells. Stereological methods using invariator, were applied for the first time to estimate cell and nucleus volume and cell surface of the infected Vero cell line with the measles virus.This method can be applied on other cultured cells.Vero cells grown in tissue culture plates for 48 hours at 36˚C were infected with 100TCID50 of AiK strain of measles virus. Volume and surface of the infected Vero cells were studied at 4, 9 and 25 hours post infection along with uninfected control cells. The mean cell volume and surface of the cells infected with measles virus, increased ~87% and ~50%, respectively, 4 hours post-infection, as compared with the uninfected control. The nuclei did not show any differences. The mean parameters of infected cells in other time intervals showed no significant difference comparing with the control cells. Although there are other specific methods, stereology may be used as an integrated protocol to detect cytophatic changes of the measles virus infected cells early in the permissive cell culture system.

scholarly journals Curcumin Inhibits In Vitro SARS-CoV-2 Infection In Vero E6 Cells through Multiple Antiviral Mechanisms

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6900
Author(s):  
Damariz Marín-Palma ◽  
Jorge H. Tabares-Guevara ◽  
María I. Zapata-Cardona ◽  
Lizdany Flórez-Álvarez ◽  
Lina M. Yepes ◽  
...  
Keyword(s):  
Post Infection ◽  
Mononuclear Cells ◽  
Plaque Assay ◽  
Antiviral Effect ◽  
Peripheral Blood Mononuclear ◽  
Infection Treatment ◽  
Virucidal Effect ◽  
Anti Inflammatory ◽  
Inflammatory Effect

Due to the scarcity of therapeutic approaches for COVID-19, we investigated the antiviral and anti-inflammatory properties of curcumin against SARS-CoV-2 using in vitro models. The cytotoxicity of curcumin was evaluated using MTT assay in Vero E6 cells. The antiviral activity of this compound against SARS-CoV-2 was evaluated using four treatment strategies (i. pre–post infection treatment, ii. co-treatment, iii. pre-infection, and iv. post-infection). The D614G strain and Delta variant of SARS-CoV-2 were used, and the viral titer was quantified by plaque assay. The anti-inflammatory effect was evaluated in peripheral blood mononuclear cells (PBMCs) using qPCR and ELISA. By pre–post infection treatment, Curcumin (10 µg/mL) exhibited antiviral effect of 99% and 99.8% against DG614 strain and Delta variant, respectively. Curcumin also inhibited D614G strain by pre-infection and post-infection treatment. In addition, curcumin showed a virucidal effect against D614G strain and Delta variant. Finally, the pro-inflammatory cytokines (IL-1β, IL-6, and IL-8) released by PBMCs triggered by SARS-CoV-2 were decreased after treatment with curcumin. Our results suggest that curcumin affects the SARS-CoV-2 replicative cycle and exhibits virucidal effect with a variant/strain independent antiviral effect and immune-modulatory properties. This is the first study that showed a combined (antiviral/anti-inflammatory) effect of curcumin during SARS-CoV-2 infection. However, additional studies are required to define its use as a treatment for the COVID-19.

scholarly journals Poor vector competence of the human flea, Pulex irritans, to transmit Yersinia pestis

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Adélaïde Miarinjara ◽  
David M. Bland ◽  
James R. Belthoff ◽  
B. Joseph Hinnebusch
Keyword(s):  
Human Blood ◽  
Blood Meal ◽  
Vector Competence ◽  
Bacterial Load ◽  
Bacterial Biofilm ◽  
Rat Blood ◽  
Pulex Irritans ◽  
High Prevalence ◽  
Phase Transmission ◽  
Host Blood

Abstract Background The human flea, Pulex irritans, is widespread globally and has a long association with humans, one of its principal hosts. Its role in plague transmission is still under discussion, although its high prevalence in plague-endemic regions and the presence of infected fleas of this species during plague outbreaks has led to proposals that it has been a significant vector in human-to-human transmission in some historical and present-day epidemiologic situations. However, based on a limited number of studies, P. irritans is considered to be a poor vector and receives very little attention from public health policymakers. In this study we examined the vector competence of P. irritans collected from foxes and owls in the western United States, using a standard protocol and artificial infection system. Methods Wild-caught fleas were maintained in the laboratory and infected by allowing them to feed on human or rat blood containing 2 × 108 to 1 × 109Y. pestis/ml. The fleas were then monitored periodically for infection rate and bacterial load, mortality, feeding rate, bacterial biofilm formation in the foregut (proventricular blockage), and ability to transmit Y. pestis after their single infectious blood meal. Results P. irritans were susceptible to infection, with more than 30% maintaining high bacterial loads for up to 20 days. Transmission during this time was infrequent and inefficient, however. Consistent with previous studies, a low level of early-phase transmission (3 days after the infectious blood meal) was detected in some trials. Transmission at later time points was also sporadic, and the incidence of proventricular blockage, required for this mode of transmission, was low in fleas infected using rat blood and never occurred in fleas infected using human blood. The highest level of blockage and transmission was seen in fleas infected using rat blood and allowed to feed intermittently rather than daily, indicating that host blood and feeding frequency influence vector competence. Conclusions Our results affirm the reputation of P. irritans as a feeble vector compared to rodent flea species examined similarly, and its vector competence may be lower when infected by feeding on bacteremic human blood. Graphic abstract

scholarly journals Vector competence ofAnophelesandCulexmosquitoes for Zika virus

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3096 ◽  
Author(s):  
Brittany L. Dodson ◽  
Jason L. Rasgon
Keyword(s):  
Anopheles Gambiae ◽  
Culex Quinquefasciatus ◽  
Zika Virus ◽  
Anopheles Stephensi ◽  
Vector Competence ◽  
Mosquito Species ◽  
Plaque Assay ◽  
Virus Transmission ◽  
Serious Disease ◽  
Blood Meals

Zika virus is a newly emergent mosquito-borne flavivirus that has caused recent large outbreaks in the new world, leading to dramatic increases in serious disease pathology including Guillain-Barre syndrome, newborn microcephaly, and infant brain damage. AlthoughAedesmosquitoes are thought to be the primary mosquito species driving infection, the virus has been isolated from dozens of mosquito species, includingCulexandAnophelesspecies, and we lack a thorough understanding of which mosquito species to target for vector control. We exposedAnopheles gambiae,Anopheles stephensi, andCulex quinquefasciatusmosquitoes to blood meals supplemented with two Zika virus strains. Mosquito bodies, legs, and saliva were collected five, seven, and 14 days post blood meal and tested for infectious virus by plaque assay. Regardless of titer, virus strain, or timepoint,Anopheles gambiae,Anopheles stephensi, andCulex quinquefasciatusmosquitoes were refractory to Zika virus infection. We conclude thatAnopheles gambiae,Anopheles stephensi, andCulex quinquefasciatusmosquitoes likely do not contribute significantly to Zika virus transmission to humans. However, future studies should continue to explore the potential for other novel potential vectors to transmit the virus.

scholarly journals Inhibition of Autophagy by 3-Methyladenine restricts Murine Cytomegalo virus Replication

2020 ◽  
Author(s):  
Xinyan Zhang ◽  
Linlin Zhang ◽  
Yidan Bi ◽  
Ting Xi ◽  
Zhan Zhang ◽  
...  
Keyword(s):  
Cell Death ◽  
Virus Replication ◽  
Post Infection ◽  
Caspase 3 ◽  
Plaque Assay ◽  
Virus Titer ◽  
Kinase Domain ◽  
Host Cells ◽  
Mcmv Infection ◽  
Related Factors

Abstract Background:Cytomegalovirus (CMV) could induce autophagy early upon infection, which might have an impact on virus replication and the survival of host cells. The purpose ofthe present study was to determine how autophagy effects virus replication and whether it is associated with caspase-3 dependent apoptosis duringmurine cytomegalovirus (MCMV) infection. Methods:The eyecup isolated from adultC57BL/6J mice (6-8 weeks old) and mouse embryo fibroblast cells (MEFs) were cultured and infected with MCMV K181 strain, following by treated with 3-methyladenine (3-MA)or rapamycin to block or activate autophagy.Immunofluorescence staining and western blot were used to detect the expression of early antigen (EA) of MCMV, autophagy and cell death related factors. Plaque assay was performed to detect the virus titer in different groups. TUNEL assay was used to measure the percentage of cell death.Results: Results showed that autophagy was induced at 24,72 and 96hours post infection (hpi)with MCMV in MEFs. In the eyecup culture, it also showed that autophagy was induced at 4 and 7days post infection (dpi).In addition, caspase-3 dependent apoptosis and receptor-interacting kinase 1/ receptor-interacting kinase 3/mixed lineage kinase domain-like protein (RIPK1/RIPK3/MLKL) dependent necroptosis were induced by MCMV infection in eyecup.In MEFs, caspase-3 dependent apoptosis was inhibited, whileRIPK1/RIPK3/MLKL dependent necroptosis was activated with MCMV infection. Once treatment with 3-MA, there were significantly less active virus particles released in MEFs and eyecup, also EA expression was significantly inhibited in the eyecup. However, treatment with rapamycin have no such significant influence on either virus titer or EA expression in MEFs and eyecup. Furthermore, cleaved caspase-3 was elevated, while RIPK1/RIPK3/MLKL pathway was inhibited with treatment of 3-MA both in MEFs and eyecup. Conclusion:Inhibition of autophagy by 3-MA could both restrict virus replication and promote caspase-3 dependent apoptosis in the eyecup and MEFs with MCMV infection.It can be explained that on the early periodof MCMV infection, suppressed autophagy process directly reduced virus release.Thereafter, caspase-3 dependent apoptosis was activated and resulted in decreased virus replication.

scholarly journals Interactions vecteurs-virus : diversité des sérotypes et des souches de la peste équine africaine, et populations géographiques

2009 ◽  
Vol 62 (2-4) ◽  
pp. 107
Author(s):  
Gert J. Venter ◽  
I. Hermanides ◽  
D. Majatladi ◽  
S. Boikanyo ◽  
I. Wright
Keyword(s):  
South Africa ◽  
Vector Competence ◽  
Vectorial Capacity ◽  
Infection Prevalence ◽  
Culicoides Species ◽  
Vector Population ◽  
Biting Rate ◽  
Critical Components ◽  
Susceptibility Tests ◽  
Different Strains

The most abundant Culicoides species in an area is not inevi­tably the most competent vector species for a specific virus. Oral susceptibility, as an indicator of vector competence, is a measure of the portion of vectors taking a blood meal from an infected host that actually becomes infective. Cumulative laboratory oral susceptibility results from South Africa indicate a multivector potential for bluetongue virus (BTV) as well as for African horse sickness virus (AHSV). Considering the unique biology of potential vector competent Culicoides species one can appreciate the complex epidemiology of these diseases. The oral susceptibly of C. imicola, a proven vector of AHSV and BTV, was relatively low for most of the viral isolates and even appeared to be refractory to infection with some of the isolates used. This relatively low oral susceptibility may partly explain the low field infection prevalence of AHSV and BTV recorded in field collected midges. In South Africa, the relatively low oral susceptibility as determined for some of the isolates is easily compensated for by the high abundance of C. imicola. Differences found in the virus recovery rates of various AHSV serotypes/isolates from the various Culicoides species and even different populations of the same species emphasize the fact that, although oral susceptibility tests provide important information about a specific vector population, it provides no predictability about the behaviour of other populations with different strains of virus. Differences found in the oral susceptibility of C. imi­cola and C. bolitinos for isolates of the same serotypes of AHSV suggest coadaptation between orbiviruses and vectors present in a given locality. Real-time monitoring of vector competence might be difficult as it would require assessing local Culicoides populations using variants of orbiviruses currently in circula­tion. It needs to be emphasized that laboratory demonstration of oral susceptibility is not the only necessary step to implement a competent vector. It is, however, an indication of the ability of a vector to support virus replication and one of the critical components of vectorial capacity. Vector capacity is the relative measure of a vector population to transmit a virus to a vertebrate population. In addition to vector competence, vectorial capacity depends on the biting rate, host selection, vector survivorship, and the extrinsic incubation period of the virus.

scholarly journals Culex saltanensis and Culex interfor (Diptera: Culicidae) are susceptible and competent to transmit St. Louis encephalitis virus (Flavivirus: Flaviviridae) in central Argentina.

2019 ◽  
Author(s):  
Mauricio Beranek ◽  
Agustin Quaglia ◽  
Giovana Peralta ◽  
Fernando Flores ◽  
Marina Stein ◽  
...  
Keyword(s):  
Potential Role ◽  
Vector Competence ◽  
Plaque Assay ◽  
Encephalitis Virus ◽  
Culex Pipiens Quinquefasciatus ◽  
Central Argentina ◽  
Virus Dissemination ◽  
Epidemic Period ◽  
Natural Hosts ◽  
Viral Plaque

Infectious diseases caused by mosquito-borne viruses constitute health and economic problems worldwide. St. Louis encephalitis virus (SLEV) is endemic and autochthonous in the American continent. Culex pipiens quinquefasciatus is the primary urban vector of SLEV; however, Culex interfor and Culex saltanensis have also been found naturally infected with the virus, suggesting their potential role as vectors. OBJECTIVE: The aim of this study was to determine the vector competence of Cx. interfor and Cx. saltanensis for SLEV from central Argentina in comparison to Cx. p. quinquefasciatus. METHODS: Adult female mosquitoes of the three Culex species were orally infected by feeding on viremic chicks that had been inoculated with SLEV. Then, abdomens, legs and saliva blood-fed mosquitoes were analyzed by viral plaque assay and the presence of cytopathic effect on the cell culture monolayer. RESULTS: Mosquitoes were permissive to orally acquired infections, to virus dissemination, and transmission of SLEV in the saliva. Cx. saltanensis and Cx. interfor are potential vectors of SLEV. CONCLUSIONS: Our results demonstrate that in Argentina both Cx. saltanensis and Cx. interfor are susceptible to SLEV and competent for its transmission. Moreover they are abundant during SLEV epidemic period in urban area, positive for this virus in nature, and found to feed on natural hosts.

scholarly journals Sugar feeding protects against arboviral infection by enhancing gut immunity in the mosquito vector Aedes aegypti

2021 ◽  
Vol 17 (9) ◽  
pp. e1009870
Author(s):  
Floriane Almire ◽  
Selim Terhzaz ◽  
Sandra Terry ◽  
Melanie McFarlane ◽  
Rommel J. Gestuveo ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Blood Meal ◽  
Vector Competence ◽  
Antiviral Immunity ◽  
Infection Prevalence ◽  
Sugar Intake ◽  
Sugar Feeding ◽  
Induced Immunity ◽  
Mosquito Females

As mosquito females require a blood meal to reproduce, they can act as vectors of numerous pathogens, such as arboviruses (e.g. Zika, dengue and chikungunya viruses), which constitute a substantial worldwide public health burden. In addition to blood meals, mosquito females can also take sugar meals to get carbohydrates for their energy reserves. It is now recognised that diet is a key regulator of health and disease outcome through interactions with the immune system. However, this has been mostly studied in humans and model organisms. So far, the impact of sugar feeding on mosquito immunity and in turn, how this could affect vector competence for arboviruses has not been explored. Here, we show that sugar feeding increases and maintains antiviral immunity in the digestive tract of the main arbovirus vector Aedes aegypti. Our data demonstrate that the gut microbiota does not mediate the sugar-induced immunity but partly inhibits it. Importantly, sugar intake prior to an arbovirus-infected blood meal further protects females against infection with arboviruses from different families. Sugar feeding blocks arbovirus initial infection and dissemination from the gut and lowers infection prevalence and intensity, thereby decreasing the transmission potential of female mosquitoes. Finally, we show that the antiviral role of sugar is mediated by sugar-induced immunity. Overall, our findings uncover a crucial role of sugar feeding in mosquito antiviral immunity which in turn decreases vector competence for arboviruses. Since Ae. aegypti almost exclusively feed on blood in some natural settings, our findings suggest that this lack of sugar intake could increase the spread of mosquito-borne arboviral diseases.

Brazilian Aedes aegypti as a competent vector for multiple complex arboviral coinfections

2021 ◽  
Author(s):  
Nilton Barnabé Rodrigues ◽  
Raquel Soares Maia Godoy ◽  
Alessandra Silva Orfano ◽  
Barbara Aparecida Chaves ◽  
Thais Bonifácio Campolina ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Infection Rate ◽  
Yellow Fever ◽  
Vector Competence ◽  
Survival Rates ◽  
Multiple Infection ◽  
Single Infection ◽  
Multiple Infections ◽  
Viral Abundance ◽  
Disseminated Infection

Abstract Background Aedes aegypti is a highly competent vector in the transmission of arboviruses, such as chikungunya, dengue, Zika and yellow fever, and causes single and coinfections in the populations of tropical countries. Methods The infection rate, viral abundance, vector competence, disseminated infection and survival rate were recorded after single and multiple infections of the vector with 15 combinations of chikungunya, dengue, Zika and yellow fever arboviruses. Results Infection rates were 100% in all single and multiple infection experiments, except in one triple coinfection that presented a rate of 50%. The vector competence and disseminated infection rate varied from 100% (in single and quadruple infections) to 40% (in dual and triple infections). The dual and triple coinfections altered the vector competence and/or viral abundance of at least one of the arboviruses. The highest viral abundances were detected for a single infection with chikungunya. The viral abundances in quadruple infections were similar when compared to each respective single infection. A decrease in survival rates was observed in a few combinations. Conclusions Ae. aegypti was able to host all single and multiple arboviral coinfections. The interference of the chikungunya virus suggests that distinct arbovirus families may have a significant role in complex coinfections.

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