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Evidence of co-infection of chikungunya and densonucleosis viruses in C6/36 cell lines and laboratory infected Aedes aegypti (L.) mosquitoes.

ABSTRACT: BACKGROUND: Densonucleosis viruses are the etiological agents of insect's disease. We have reported the isolation of densovirus from India and its distribution among the natural populations of Aedes aegypti mosquitoes across the country. Since densonucleosis virus persistently infects mosquito populations, and is demonstrated to negatively affect multiplication of dengue virus in Aedes albopictus, it would be interesting to study if this virus has a role in determining the susceptibility of the vector mosquito Ae. aegypti to chikugunya virus. METHODS: Mosquito cell lines and adult Ae. aegypti mosquitoes infected with densovirus were superinfected with Chikungunya virus and both the viruses were quantitated by determining their genomic copy number by real time amplification. Comparison was made between the log of genomic copy numbers of the viruses in the presence and absence of each other. RESULTS: The log of copy number of the viruses did not vary due to co-infection. Even though the RNA copy number of chikungunya virus increased over the period of time, no change was observed in the RNA copy number between the control and the co-infected group on any given day. Similarly, DNA copy number of densovirus also remained unchanged between the control and the co-infected groups. CONCLUSION: Chikungunya virus neither stimulates the replication of densovirus nor is its own replication suppressed due to co-infection. Ae. aegypti mosquitoes with densovirus infection were as susceptible to infection by chikungunya virus as the uninfected mosquitoes.

SUBMITTER: Sivaram A

PROVIDER: S-EPMC2964651 | biostudies-literature | 2010

REPOSITORIES: biostudies-literature

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Evidence of co-infection of chikungunya and densonucleosis viruses in C6/36 cell lines and laboratory infected Aedes aegypti (L.) mosquitoes.

Sivaram Aruna A Barde Pradip V PV Gokhale Mangesh D MD Singh Dinesh K DK Mourya Devendra T DT

Parasites & vectors 20101012

<h4>Background</h4>Densonucleosis viruses are the etiological agents of insect's disease. We have reported the isolation of densovirus from India and its distribution among the natural populations of Aedes aegypti mosquitoes across the country. Since densonucleosis virus persistently infects mosquito populations, and is demonstrated to negatively affect multiplication of dengue virus in Aedes albopictus, it would be interesting to study if this virus has a role in determining the susceptibility ...[more]

PMID: 20939884

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Project description:BackgroundVertical transmission (VT) of arboviruses (arthropod-borne viruses) can serve as an essential link in the transmission cycle during adverse environmental conditions. The extent of VT among mosquito-borne arboviruses can vary significantly among different virus families and even among different viruses within the same genus. For example, orthobunyaviruses exhibit a higher VT rate than orthoflaviviruses and alphaviruses. Mosquitoes are also the natural hosts of a large number of insect-specific viruses (ISV) that belong to several virus families, including Bunyaviridae, Flaviviridae, and Togaviridae. Cell fusing agent virus (CFAV), an insect-specific orthoflavivirus, displays higher VT rates than other dual-host orthoflaviviruses, such as Zika and dengue viruses. High VT rates require establishment of stabilized infections in the germinal tissues of female vectors. To delve deeper into understanding the mechanisms governing these differences in VT rates and the establishment of stabilized infections, the ovary infection patterns and VT of Zika virus (ZIKV) and CFAV were compared.MethodsLaboratory colonized Aedes aegypti females were infected with either ZIKV or CFAV by intrathoracic injection. Ovary infection patterns were monitored by in situ hybridization using virus-specific probes, and VT was determined by detecting the presence of the virus among the progeny, using a reverse-transcription quantitative polymerase chain reaction (PCR) assay.ResultsBoth ZIKV and CFAV infect mosquito ovaries after intrathoracic injection. Infections then become widespread following a non-infectious blood meal. VT rates of ZIKV are similar to previously reported results (3.33%). CFAV, on the contrary transmits vertically very rarely. VT was not observed in the first gonotrophic cycle following intrathoracic injection, and only rarely in the second gonotrophic cycle. VT of CFAV is mosquito population independent, since similar results were obtained with Aedes aegypti collected from two different geographic locations.ConclusionsAlthough CFAV infects mosquito ovaries, the occurrence of VT remains infrequent in artificially infected Ae. aegypti, despite the observation of high VT rates in field-collected mosquitoes. These results suggest that infections of insect-specific viruses are stabilized in mosquitoes by some as yet unidentified mechanisms.

Project description:BackgroundArthropod borne virus infections cause several emerging and resurgent infectious diseases. Among the diseases caused by arboviruses, dengue and chikungunya are responsible for a high rate of severe human diseases worldwide. The midgut of mosquitoes is the first barrier for pathogen transmission and is a target organ where arboviruses must replicate prior to infecting other organs. A proteomic approach was undertaken to characterize the key virus/vector interactions and host protein modifications that happen in the midgut for viral transmission to eventually take place.Methodology and principal findingsUsing a proteomics differential approach with two-Dimensional Differential in-Gel Electrophoresis (2D-DIGE), we defined the protein modulations in the midgut of Aedes aegypti that were triggered seven days after an oral infection (7 DPI) with dengue 2 (DENV-2) and chikungunya (CHIKV) viruses. Gel profile comparisons showed that the level of 18 proteins was modulated by DENV-2 only and 12 proteins were modulated by CHIKV only. Twenty proteins were regulated by both viruses in either similar or different ways. Both viruses caused an increase of proteins involved in the generation of reactive oxygen species, energy production, and carbohydrate and lipid metabolism. Midgut infection by DENV-2 and CHIKV triggered an antioxidant response. CHIKV infection produced an increase of proteins involved in detoxification.Conclusion/significanceOur study constitutes the first analysis of the protein response of Aedes aegypti's midgut infected with viruses belonging to different families. It shows that the differentially regulated proteins in response to viral infection include structural, redox, regulatory proteins, and enzymes for several metabolic pathways. Some of these proteins like antioxidant are probably involved in cell protection. On the other hand, we propose that the modulation of other proteins like transferrin, hsp60 and alpha glucosidase, may favour virus survival, replication and transmission, suggesting a subversion of the insect cell metabolism by the arboviruses.

Project description:The chikungunya virus (CHIKV) is transmitted by female Aedes aegypti and Aedes albopictus mosquitoes, mostly present in (sub)tropical regions. No antivirals are available to treat CHIKV infections. If antiviral drugs are proven efficient to treat CHIKV-infected patients, it will be pivotal to determine whether drug-resistant viruses can be transmitted from one human to another by their mosquito vectors. We orally infected Aedes aegypti mosquitoes with a blood meal containing wild-type or drug-resistant CHIKV variants (i.e., MADTPres CHIKV, with mutation in the nsP1 gene, and T-705res CHIKV, with mutation in the RNA-dependent RNA polymerase [RdRp] gene). Viral loads were quantified in bodies (infection), heads (dissemination), and saliva (transmission) of individual mosquitoes. The infection rate of the resistant viruses was similar to that of the wild-type virus. However, the dissemination of T-705res CHIKV was markedly decreased compared to wild-type and MADTPres CHIKV. Furthermore, T-705res CHIKV was only transmitted in the saliva at day 20 postinfection (p.i.), whereas transmission of wild-type CHIKV was observed at day 3 p.i. The attenuated phenotype of the T-705res virus was confirmed in mosquito cell culture, whereas the replication fitness in Vero cells was similar to that of the wild type. In bodies and heads of mosquitoes infected with the resistant variants, the resistant phenotype and genotype were retained. Also in the saliva, the resistant genotype of MADTPres CHIKV was maintained. Our results illustrate that the fitness of drug-resistant variants should be evaluated in both hosts to be able to select antiviral drugs with a limited risk for the spread of drug resistance by mosquitoes.IMPORTANCE Because of its global reemergence and unusual morbidities associated with infection, the chikungunya virus (CHIKV) has become a substantial public health problem. However, no antivirals are currently available to treat CHIKV infections. If antiviral drugs will prove to be efficient to treat CHIKV-infected patients, it will be essential to understand if drug-resistant viruses can be transmitted from one human to another by the mosquito. We therefore orally infected Aedes mosquitoes with drug-resistant CHIKV variants and determined the replication and transmission levels. One of the antiviral drug-resistant CHIKV variants could efficiently replicate and disseminate in both laboratory and field-collected mosquitoes. In addition, this variant retained its drug-resistant genotype in the saliva. In contrast, the other drug-resistant variant was markedly attenuated in mosquitoes. Our results illustrate that extra caution for drug resistance should be considered when developing an antiarbovirus antiviral in order to minimize the risk of spreading drug resistance by mosquitoes.

Project description:BACKGROUND:Chikungunya virus (CHIKV) is a re-emerging arthropod-borne (arbo)virus that causes chikungunya fever in humans and is predominantly transmitted by Aedes aegypti mosquitoes. The CHIKV replication machinery consists of four non-structural proteins (nsP1-4) that additionally require the presence of a number of host proteins for replication of the viral RNA. NsP3 is essential for CHIKV replication and has a conserved macro, central and C-terminal hypervariable domain (HVD). The HVD is intrinsically disordered and interacts with various host proteins via conserved short peptide motifs: A proline-rich (P-rich) motif that has affinity for SH3-domain containing proteins and duplicate FGDF motifs with affinity for G3BP and its mosquito homologue Rasputin. The importance of these motifs for infection of mammalian cells has previously been implicated. However, their role during CHIKV infection of mosquito cells and transmission by mosquitoes remains unclear. METHODOLOGY / PRINCIPAL FINDINGS:Here, we show that in-frame deletion of the P-rich motif is lethal for CHIKV replication in both mosquito and mammalian cells. However, while mutagenesis of the P-rich motif negatively affects replication both in mammalian and mosquito cells, it did not compromise the infection and transmission of CHIKV by Ae. aegypti mosquitoes. Mutagenesis of both FGDF motifs together completely inactivated CHIKV replication in both mammalian and mosquito cells. Importantly, mutation of a single FGDF motif attenuated CHIKV replication in mammalian cells, while replication in mosquito cells was similar to wild type. Surprisingly, CHIKV mutants containing only a single FGDF motif were efficiently transmitted by Ae. aegypti. CONCLUSIONS / SIGNIFICANCE:The P-rich motif in CHIKV nsP3 is dispensable for transmission by mosquitoes. A single FGDF motif is sufficient for infection and dissemination in mosquitoes, but duplicate FGDF motifs are required for the efficient infection from the mosquito saliva to a vertebrate host. These results contribute to understanding the dynamics of the alphavirus transmission cycle and may help the development of arboviral intervention strategies.

Project description:BackgroundThe ability of blood-feeding arthropods to successfully acquire and transmit pathogens of medical and veterinary importance has been shown to be interfered with, or enhanced by, the arthropod's native microbiome. Mosquitoes transmit viruses, protozoan and filarial nematodes, the majority of which contribute to the 17% of infectious disease cases worldwide. Dirofilaria immitis, a mosquito-transmitted filarial nematodes of dogs and cats, is vectored by several mosquito species including Aedes aegypti.MethodsIn this study, we investigated the impact of D. immitis colonization on the microbiome of laboratory reared female Ae. aegypti. Metagenomic analysis of the V3-V4 variable region of the microbial 16S RNA gene was used for identification of the microbial differences down to species level.ResultsWe generated a total of 1068 OTUs representing 16 phyla, 181 genera and 271 bacterial species. Overall, in order of abundance, Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes were the most represented phylum with D. immitis-infected mosquitoes having more of Proteobacteria (71%) than uninfected mosquitoes (56.9%). An interesting finding in this study is the detection of Klebsiella oxytoca in relatively similar abundance in infected and uninfected mosquitoes, suggesting a possible endosymbiotic relationship, and has been previously shown to indirectly compete for nutrients with fungi on domestic housefly eggs and larvae. While D. immitis colonization has no effect on the overall species richness, we identified significant differences in the composition of selected bacterial genera and phyla between the two groups. We also reported distinct compositional and phylogenetic differences in the individual bacterial species when commonly identified bacteria were compared.ConclusionsTo the best of our knowledge, this is the first study to understand the impact of a filarial infection on the microbiome of its mosquito vector. Further studies are required to identify bacteria species that could play an important role in the mosquito biology. While the microbiome composition of Ae. aegypti mosquito have been previously reported, our study shows that in an effort to establish itself, a filarial nematode modifies and alters the overall microbial diversity within its mosquito host.

Dataset Information

Evidence of co-infection of chikungunya and densonucleosis viruses in C6/36 cell lines and laboratory infected Aedes aegypti (L.) mosquitoes.

Publications

Evidence of co-infection of chikungunya and densonucleosis viruses in C6/36 cell lines and laboratory infected Aedes aegypti (L.) mosquitoes.

Similar Datasets

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