Abstract
BackgroundDengue is an arboviral disease caused by dengue virus (DENV), whose main vectors are the mosquitoes Aedes aegypti and Aedes albopictus. A. aegypti is the only DENV vector in Cape Verde, an African country that suffered its first outbreak of dengue in 2009. However, little is known about the variation in the level of vector competence of this mosquito population to the different DENV serotypes. This study aimed to evaluate the vector competence of A. aegypti from the island of Santiago, Cape Verde, to four DENV serotypes and to detect DENV vertical transmission.MethodsMosquitoes were fed on blood containing DENV serotypes and were dissected at 7, 14 and 21 days post-infection (dpi) to detect the virus in the midgut, head and salivary glands (SG) using RT-PCR. Additionally, the number of copies of viral RNA present in the SG was determined by qRT-PCR. Furthermore, eggs were collected in the field and adult mosquitoes obtained were analyzed by RT-PCR and the platelia dengue NS1 antigen kit to detect transovarial transmission.ResultsHigh rates of SG infection were observed for DENV-2 and DENV-3 whereas for DENV-1, viral RNA was only detected in the midgut and head. DENV-4 did not spread to the head or SG, maintaining the infection only in the midgut. The number of viral RNA copies in the SG did not vary significantly between DENV-2 and DENV-3 or among the different periods of incubation and the various titers of DENV tested. With respect to DENV surveillance in mosquitoes obtained from the eggs collected in the field, no samples were positive.ConclusionAlthough no DENV positive samples were collected from the field in 2014, it is important to highlight that the A. aegypti population from Santiago Islands exhibited different degrees of susceptibility to DENV serotypes. This population showed a high vector competence for DENV-2 and DENV-3 strains and a low susceptibility to DENV-1 and DENV-4. Viral RNA copies in the SG remained constant for at least 21 dpi, which may enhance the vector capacity of A. aegypti and suggests the presence of a mechanism modulating virus replication in the SG.
Highlights
Dengue is an arboviral disease caused by dengue virus (DENV), whose main vectors are the mosquitoes Aedes aegypti and Aedes albopictus
Conclusion: no DENV positive samples were collected from the field in 2014, it is important to highlight that the A. aegypti population from Santiago Islands exhibited different degrees of susceptibility to DENV serotypes
Infection with DENV-2 Unlike DENV-1, DENV-2 was detected in the midgut at 7 dpi, reaching infection rates of 50% and 70% in the 1st (1.4 × 105 focus-forming unit/ml (FFU/ml)) and 2nd experiment (2 × 105 FFU/ml), Table 1 Midgut infection rate, dissemination rate and vector competence estimated by RT-PCR using NS5 gene for the
Summary
Dengue is an arboviral disease caused by dengue virus (DENV), whose main vectors are the mosquitoes Aedes aegypti and Aedes albopictus. Dengue is caused by a flavivirus named Dengue virus (DENV), which is transmitted to humans by mosquitoes of the genus Aedes, principally Aedes aegypti and Aedes albopictus [3]. This virus comprises different serotypes that evolved in nonhuman primates from a common ancestor and entered the urban cycle approximately 100– 1500 years ago [4]. Despite the vast knowledge of the virus and the great epidemiological importance of this disease, there are currently no specific antiviral therapies or commercially available vaccines against all serotypes of DENV, which limits the prevention of viral transmission to vector control
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
