ABSTRACT
Dengue virus has recently reemerged in the southern Indian Ocean islands, causing outbreaks in Reunion Island and the Seychelles. In the present study, we determined the complete genome sequences of closely related clinical isolates of dengue virus type 2 circulating in the Seychelles in 2016 and Reunion Island in 2018.
ABSTRACT
The rapid spread of Zika virus (ZIKV) in the Americas raised many questions about the role of Culex quinquefasciatus mosquitoes in transmission, in addition to the key role played by the vector Aedes aegypti. Here we analysed the competence of Cx. quinquefasciatus (with or without Wolbachia endosymbionts) for a ZIKV isolate. We also examined the induction of RNA interference pathways after viral challenge and the production of small virus-derived RNAs. We did not observe any infection nor such small virus-derived RNAs, regardless of the presence or absence of Wolbachia. Thus, Cx. quinquefasciatus does not support ZIKV replication and Wolbachia is not involved in producing this phenotype. In short, these mosquitoes are very unlikely to play a role in transmission of ZIKV.
Subject(s)
Culex/virology , Mosquito Vectors/virology , Virus Replication , Wolbachia/physiology , Zika Virus Infection/transmission , Zika Virus/physiology , Animals , Female , Phenotype , Zika Virus Infection/virologyABSTRACT
We report that two laboratory colonies of Culex quinquefasciatus and Culex pipiens mosquitoes were experimentally unable to transmit ZIKV either up to 21 days post an infectious blood meal or up to 14 days post intrathoracic inoculation. Infectious viral particles were detected in bodies, heads or saliva by a plaque forming unit assay on Vero cells. We therefore consider it unlikely that Culex mosquitoes are involved in the rapid spread of ZIKV.
Subject(s)
Culex/virology , Disease Transmission, Infectious , Zika Virus Infection/transmission , Zika Virus Infection/virology , Zika Virus/isolation & purification , Animals , Disease Models, Animal , Head/virology , Insect Vectors/virology , Saliva/virology , Salivary Glands/virology , Time Factors , Vero Cells/pathology , Viral Load , Viral Plaque AssayABSTRACT
Trypanosoma secretome was shown to be involved in parasite virulence and is suspected of interfering in parasite life-cycle steps such as establishment in the Glossina midgut, metacyclogenesis. Therefore, we attempted to identify the proteins secreted by procyclic strains of T. brucei gambiense and T. brucei brucei, responsible for human and animal trypanosomiasis, respectively. Using mass spectrometry, 427 and 483 nonredundant proteins were characterized in T. brucei brucei and T. brucei gambiense secretomes, respectively; 35% and 42% of the corresponding secretome proteins were specifically secreted by T. brucei brucei and T. brucei gambiense, respectively, while 279 proteins were common to both subspecies. The proteins were assigned to 12 functional classes. Special attention was paid to the most abundant proteases (14 families) because of their potential implication in the infection process and nutrient supply. The presence of proteins usually secreted via an exosome pathway suggests that this type of process is involved in trypanosome ESP secretion. The overall results provide leads for further research to develop novel tools for blocking trypanosome transmission.
