A Single-Tube RT-PCR Amplification for Detection of Rift Valley Fever Virus

Entomologic investigations were conducted in the Al-Darb, Al-Reath, Al-Aridah, Abuareesh, Al-Ahad, Samttah, Sabyah, Damad and Beash areas by CO2-baited CDC miniature light traps in the Jazan region. Vectors were identified morphologically, as well as COI gene segment amplification and sequencing. The relative abundance (RA%) and pattern of occurrence (C%) were recorded. The presence of the Rift Valley fever virus (RVFV) in pooled mosquito samples was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR). Culex pipiens (C. pipiens) and Culex tritaeniorhynchus (C. tritaeniorhynchus) were found with RA% values of 96% and 4%, respectively, in the region. Significant variations in vector population densities were observed in different districts. The C. pipiens was found highly abundant in all districts and RA% value (100%) was recorded in the Al-Darb, Al-Reath, Al-Aridah, Samttah and Damad areas, whereas RA% values (93.75%, 93.33%, 92.30% and 91.66%) were noted in Al-Ahad, Sabyah, Abuareesh and Beash districts, respectively. RA% values for C. tritaeniorhynchus were recorded as 8.33%, 7.70%, 6.66% and 6.25% in Beash, Abuareesh, Sabyah and Al-Ahad areas, respectively. The pattern of occurrence for C. pipiens and C. tritaeniorhynchus was recorded as 100% and 44.4% in the region. Phylogenetic analysis of C. pipiens and C. tritaeniorhynchus exhibited a close relationship with mosquitoes from Kenya and Turkey, respectively. All mosquito samples tested by RT-PCR were found negative for RVFV. In summary, the current study assessed the composition, abundance, distribution of different mosquito vectors and presence of RVFV in different areas of the Jazan region. Our data will help risk assessments of RVFV future re-emergence in the region.

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Detection of Rift Valley Fever Virus Lineage H from South Africa through Syndromic Sentinel Surveillance Network in Senegal

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab655 ◽

2021 ◽

Author(s):

Ndeye Sakha Bob ◽

Mamadou Aliou Barry ◽

Moussa Moise Diagne ◽

Martin Faye ◽

Marie Henriette Dior Ndione ◽

...

Keyword(s):

South Africa ◽

Rift Valley ◽

Surveillance System ◽

Rift Valley Fever ◽

Rift Valley Fever Virus ◽

Fever Virus ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

Surveillance Network ◽

Valley Fever

Abstract Background Rift Valley fever virus (RVFV) is an arbovirus that causes epizootics and epidemics among livestock population and humans. Our surveillance system has revealed multiple emergences and re-emergences of RVFV in West Africa over the last decade. Methods In Senegal a sentinel syndromic surveillance network (4S) has been implemented since 2011. Samples from human suspected arbovirus infection in 4S sentinel sites were sent to Institut Pasteur de Dakar (IPD) where arbovirus diagnosis by enzyme-linked immunosorbent assay (ELISA), real-time reverse transcription polymerase chain reaction (RT-PCR), and virus isolation were performed. Overall, IPD has received a total of 1,149 samples from arboviral suspected patients through the 4S network from January to December 2020. These samples were screened for seven arboviruses including RVFV. Whole genome sequencing of positive RVFV samples by RT-PCR were performed using Illumina Miseq platform followed by genome assembly. Phylogenetic analysis were performed using MEGA X. Results Out of the 1,149 arbovirus suspected cases, four RVFV positive samples were detected with RT-PCR while five RVFV positive samples were detected by ELISA. Complete genome sequences were obtained for three strains among the four positive samples by RT-PCR. Phylogenetic analyses indicated an emergence of a virus first described in South Africa during a major outbreak. Conclusion Strong surveillance system allowed the detection of RVFV outbreak in Senegal in 2020. The obtained genomes clustered with strains from South Africa belonging to lineage H. This calls for an implementation of a strong surveillance system in wild animals, humans, and livestock simultaneously in all African Countrries.

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