Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Dec 7;7(12):420.
doi: 10.3390/tropicalmed7120420.

Analysis of a Dengue Virus Outbreak in Rosso, Senegal 2021

Idrissa Dieng  1 , Mamadou Aliou Barry  2 , Cheikh Talla  2 , Bocar Sow  2 , Oumar Faye  1 , Moussa Moise Diagne  1 , Ousseynou Sene  1 , Oumar Ndiaye  1 , Boly Diop  3 , Cheikh Tidiane Diagne  1   4 , Gamou Fall  1 , Amadou Alpha Sall  1 , Cheikh Loucoubar  2 , Ousmane Faye  1
Affiliations

Analysis of a Dengue Virus Outbreak in Rosso, Senegal 2021

Idrissa Dieng et al. Trop Med Infect Dis. .

Abstract

Senegal is hyperendemic for dengue. Since 2017, outbreaks have been noticed annually in many regions around the country, marked by the co-circulation of DENV1-3. On 8 October 2021, a Dengue virus outbreak in the Rosso health post (sentinel site of the syndromic surveillance network) located in the north of the country was notified to the WHO Collaborating Center for arboviruses and hemorrhagic fever viruses at Institut Pasteur de Dakar. A multidisciplinary team was then sent for epidemiological and virologic investigations. This study describes the results from investigations during an outbreak in Senegal using a rapid diagnostic test (RDT) for the combined detection of dengue virus non-structural protein 1 (NS1) and IgM/IgG. For confirmation, samples were also tested by real-time RT-PCR and IgM ELISA at the reference lab in Dakar. qRT-PCR positive samples were subjected to whole genome sequencing using nanopore technology. Virologic analysis scored 102 positives cases (RT-PCR, NS1 antigen detection and/or IgM) out of 173 enrolled patients; interestingly, virus serotyping showed that the outbreak was caused by the DENV-1, a serotype different from DENV-2 involved during the outbreak in Rosso three years earlier, indicating a serotype replacement. Nearly all field-tested NS1 positives samples were confirmed by qRT-PCR with a concordance of 92.3%. Whole genome sequencing and phylogenetic analysis of strains suggested a re-introduction in Rosso of a DENV-1 strain different to the one responsible for the outbreak in the Louga area five years before. Findings call for improved dengue virus surveillance in Senegal, with a wide deployment of DENV antigenic tests, which allow easy on-site diagnosis of suspected cases and early detection of outbreaks. This work highlights the need for continuous monitoring of circulating serotypes which is crucial for a better understanding of viral epidemiology around the country.

Keywords: DENV-1; NS1 RDTs; Rosso; outbreak response; re-introduction; serotype replacement.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
An epidemiological curve showing the number of confirmed dengue cases during this outbreak investigation according to the date of symptoms onset; a dashed red curve shows the moving average of confirmed dengue cases per 2 days. The size of the dot is proportional to the value of the moving average.
Figure 2
Figure 2
(A) Venn diagram showing repartition of Standard Q NS1/IgM/IgG positive test results from the field; the number of samples positives DENV according to the targeted analyte (NS1,IgM and IgG), (B) Box plot showing a comparison of the median Ct values of Standard Q DENV NS1/IgM/IgG RDT on NS1-positive and NS1-negative samples.
Figure 3
Figure 3
Maximum Likelihood tree showing the relationship and genetic diversity of Senegalese DENV-1 strains detected during this study. Sequences in this study and publicly available sequences belonging to described DENV serotypes were used. Tips are colored according to the serotype. Sequences of Rosso 2021 (this study) and those from a previous outbreak in 2018 are highlighted in grey. The tree was built using complete genomes. Only the names of Rosso sequences (RS) (2018 and 2021) are represented; the designation of all used sequences is depicted in Figure S1 (supplementary files).
See this image and copyright information in PMC

References

    1. Hotta S. Experimental studies on dengue. I. Isolation, identification and modification of the virus. J. Infect. Dis. 1952;90:1–9. doi: 10.1093/infdis/90.1.1. - DOI - PubMed
    1. Kraemer M.U.G., Sinka M.E., Duda K.A., Mylne A.Q.N., Shearer F.M., Barker C.M., Moore C.G., Carvalho R.G., Coelho G.E., Van Bortel W., et al. The global distribution of the arbovirus vectors Aedes aegypti and Ae. albopictus. Elife. 2015;4:e08347. doi: 10.7554/eLife.08347. - DOI - PMC - PubMed
    1. Messina J.P., Brady O.J., Golding N., Kraemer M.U.G., Wint G.R.W., Ray S.E., Pigott D.M., Shearer F.M., Johnson K., Earl L., et al. The current and future global distribution and population at risk of dengue. Nat. Microbiol. 2019;4:1508–1515. doi: 10.1038/s41564-019-0476-8. - DOI - PMC - PubMed
    1. WHO/TDR, editor. Dengue: Guidelines for Diagnosis, Treatment, Prevention, and Control. TDR: World Health Organization; Geneva, Switzerland: 2009. 147p New Edtion. - PubMed
    1. WHO . Global Strategy for Dengue Prevention and Control, 2012–2020. World Health Organization; Geneva, Switzerland: 2012. [(accessed on 12 September 2020)]. Available online: http://apps.who.int/iris/bitstream/10665/75303/1/9789241504034_eng.pdf.