Molecular characterization and phylogenetic analysis of Chikungunya virus during the 2016 outbreak in Sergipe, northeastern Brazil

Spatial-temporal distribution of chikungunya virus in Brazil: a review on the circulating viral genotypes and Aedes (Stegomyia) albopictus as a potential vector

Chikungunya virus (CHIKV) is mainly transmitted by the invasive mosquito Aedes (Stegomyia) aegypti in tropical and subtropical regions worldwide. However, genetic adaptations of the virus to the peri domestic mosquito vector Aedes (Stegomyia) albopictus has resulted in enhanced vector competence and associated epidemics and may contribute to further geographic expansion of CHIKV. However, evidence-based data on the relative role of Ae. albopictus in CHIKV transmission dynamics are scarce, especially in regions where Ae. aegypti is the main vector, such as in Brazil. Here, we review the CHIKV genotypes circulating in Brazil, spatial and temporal distribution of Chikungunya cases in Brazil, and susceptibility to infection and transmission (i.e., vector competence) of Ae. albopictus for CHIKV to better understand its relative contribution to the virus transmission dynamics.

Molecular characterization of Chikungunya virus recovered from patients in the Maranhão state, Brazil

BACKGROUND

Chikungunya virus (CHIKV) is an arbovirus from the Togaviridae family which has four genotypes: West African (WA), East/Central/South African (ECSA) and Asian/Caribbean lineage (AL) and Indian Ocean Lineage (IOL). The ECSA genotype was first registered in Brazil in Feira de Santana and spread to all Brazilian regions. This study reports the characterization of CHIKV isolates recovered from sera samples of fifty patients from seventeen cities in Maranhão, a state from Brazilian northeast region and part of the Legal Amazon area.

METHODS AND RESULTS

Primers were developed to amplify the partial regions coding structural proteins (E1, E3, E2, 6 K, and Capsid C). The consensus sequences have 2871 bp, covering approximately 24% of the genome. The isolates were highly similar (> 99%) to the ECSA isolate from Feira de Santana (BHI3734/H804698), presenting 30 non-synonymous mutations in E1 (5.95%), 18 in E2 (4.46%), and 1 in E3 (3.03%), taking the BHI3734/H804698 isolate as standard. Although the mutations described have not previously been related to increased infectivity or transmissibility of CHIKV, in silico analysis showed changes in physicochemical characteristics, antigenicity, and B cell epitopes of E1 and E2.

CONCLUSIONS

These findings demonstrate the importance of molecular approaches for monitoring the viral adaptations undergone by CHIKV and its geographic distribution.

Identification and molecular docking of novel chikungunya virus NSP4 inhibitory peptides from camel milk proteins

The chikungunya (CHIK) virus is an arbovirus belonging to the alphavirus (Togaviridae family). Around 85% of infected individuals suffer from symptoms such as high fever and severe joint pain; about 30 to 40% will develop a chronic joint illness. The Nsp4 protease is the most conserved protein in the alphavirus family and serves as an RNA-dependent RNA polymerase (RdRp). Targeting this enzyme might inhibit the CHIKV replication cycle. This work aims to in silico study the CHIKV RdRp inhibitory effect of peptides derived from camel milk protein as antiviral peptides. Various bioinformatics tools were recruited to identify, screen, predict and assess peptides obtained from camel milk as antiviral peptides (AVPs). During this study, CHIKV Nsp4 (polymerase) was used as a target to be inhibited by interaction with peptides derived from camel milk protein. Among 91 putative bioactive peptides, the best predicted 5 were further evaluated. Molecular docking showed that the top 5 AVPs generated better docking scores and interacted well with active sites of Nsp4 by the formation of different hydrogen bonds as well as other bonds. AVP63 and AVP20 showed the best Molecular docking and MD simulation results. The residue 315ASP of the GDD motif (catalytic core) exhibited a favorable interaction with the AVPs. The findings of this study suggest that the AVP20 derived from camel milk protein can be a potential novel CHIKV polymerase inhibitor.Communicated by Ramaswamy H. Sarma.

The First Genomic Characterization of the Chikungunya Virus in Saudi Arabia

BACKGROUND

Chikungunya is an arboviral infection caused by the Chikungunya virus (CHIKV) transmitted to humans by mosquitoes of Aedes spp. CHIKV has been confined to African countries and South-East Asia up to 2004, but since then, the pathogen has become more global, and its high morbidity rate has become more visible. Saudi Arabia is not an endemic region of CHIKV, and the virus's origin is not yet fully understood. This study aimed to characterize the genome of CHIKV from samples detected in Jeddah in 2018.

METHOD

Twenty-two sets of primers were designed to amplify near-full length genome of CHIKV. RT-PCR was conducted from clinical samples. Two samples were used for studying near complete genome sequence while the remaining samples were used to study the E1 gene. Different bioinformatics tools were utilized.

RESULTS

Phylogenetic analysis showed that the CHIKV strains clustered with strains isolated from Kenya during 2017-2018 and belonged to ECSA genotype. E1: L136F, K211E and I317V mutations were identified in our strains. Also, E2: M74I, A76T, and V264A mutations were documented. Additionally, the capsid N79S substitution was also detected.

CONCLUSION

The genome of CHIKV was analyzed for the first time in Saudi Arabia to better understand the origin of the CHIKV and its genetic diversity, which showed high similarity with IE-a subclade of CHIKV strains detected in Mombasa (Kenya) indicating its possible origin.

Dengue-2 and Guadeloupe Mosquito Virus RNA Detected in Aedes (Stegomyia) spp. Collected in a Vehicle Impound Yard in Santo André, SP, Brazil

In 2018-2019, we conducted mosquito collections in a municipal vehicle impound yard, which is 10 km from the Serra do Mar Environmental Protection Area in Santo André, SP, Brazil. Our aim is to study arboviruses in the impound yard, to understand the transmission of arboviruses in an urban environment in Brazil. We captured the mosquitoes using human-landing catches and processed them for arbovirus detection by conventional and quantitative RT-PCR assays. We captured two mosquito species, Aedes aegypti (73 total specimens; 18 females and 55 males) and Ae. albopictus (34 specimens; 27 females and 7 males). The minimum infection rate for DENV-2 was 11.5 per 1000 (CI95%: 1-33.9). The detection of DENV-2 RNA in an Ae. albopictus female suggests that this virus might occur in high infection rates in the sampled mosquito population and is endemic in the urban areas of Santo André. In addition, Guadeloupe mosquito virus RNA was detected in an Ae. aegypti female. To our knowledge, this was the first detection of the Guadeloupe mosquito virus in Brazil.