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This week’s virus of the week is Dengue virus! This virus belongs to the Flavivirus genus and has a positive sense, single stranded RNA genome.

Etymology, where does the name come from?

There are several possibilities:

  • Swahili phrase Ka-dinga pepo (cramp like seizure caused by an evil spirit), which potentially originated from the Spanish word ‘dengue’ meaning careful.
  • Alternatively, posture described resembled a ‘dandy’ in English hence ‘dandy-fever’, (Halstead, 2008) .

What are the Hosts of Dengue Virus?

  • Natural cycles exist between Aedes mosquitoes and non-human primates like gorillas.
  • Rarely, this virus emerges into humans!

Cell tropism of Dengue virus – which cells do they infect?

  • Cutaenous Langerhans Dendritic cells – which are found in the skin.
  • Various immune cells! Including Monocytes, macrophages, as well as B-cells and T-cells.
  • Cells in the brain
  • Endothelial cells, which can be found in blood vessels for example.

Transmission

  • Aedes mosquitoes are responsible for Dengue transmission.
  • The most prolific mosquito being Aedes aegypti.

Pathology

There are actually three phases to the Dengue virus infection

Phase 1:

Also known as the febrile phase, where an infected person will have a fever and flu-like symptoms, and potentially a rash. This can last between 3-7 days, and most patients recover after this period.

Phase 2:

Also known as the critical phase, which occurs mainly in children and younger adults. This phase is associated with a vascular leakage syndrome causing low protein and high cell-debris in the blood with fluid around the lungs.

Phase 3:

The recovery phase which can sometimes be associated with another rash.

A second Dengue virus infection is often more severe than the first infection, this is due to a phenomenon known as antibody-dependent enhancement (ADE).

Did you know?

The first suspected cases of Dengue are found in Chinese Medical Textbooks which date back to 992.

References

  • Balsitis, S. J., Coloma, J., Castro, G., Alava, A., Flores,D., McKerrow, J. H., Beatty, P. R., & Harris, E. (2009). Tropism of dengue virus in mice and humans defined by viral nonstructural protein  3-specific immunostaining. The American Journal of Tropical Medicine and Hygiene, 80(3), 416–424.
  • Blackley, S., Kou, Z., Chen, H., Quinn, M., Rose, R. C., Schlesinger, J. J., Coppage, M., & Jin, X. (2007). Primary human splenic macrophages, but not T or B cells, are the principal target  cells for dengue virus infection in vitro. Journal of Virology, 81(24), 13325–13334. https://doi.org/10.1128/JVI.01568-07.
  • Halstead, S. B. (2008). Dengue (Vol. 5). Imperial College Press. https://doi.org/10.1142/p570 Holmes, E. C., & Twiddy, S. S. (2003). The origin, emergence and evolutionary genetics of dengue virus. Infection, Genetics and Evolution, 3(1), 19–28. https://doi.org/10.1016/S1567-1348(03)00004-2.
  • Jessie, K., Fong, M. Y., Devi, S., Lam, S. K., & Wong, K. T. (2004). Localization of dengue virus in naturally infected human tissues, by  immunohistochemistry and in situ hybridization. The Journal of Infectious Diseases, 189(8), 1411–1418. https://doi.org/10.1086/383043.
  • King, A. D., Nisalak, A., Kalayanrooj, S., Myint, K. S., Pattanapanyasat, K., Nimmannitya, S., & Innis, B. L. (1999). B cells are the principal circulating mononuclear cells infected by dengue virus. The Southeast Asian Journal of Tropical Medicine and Public Health, 30(4), 718–728.
  • Martins, S. de T., Silveira, G. F., Alves, L. R., Duarte dos Santos, C. N., & Bordignon, J. (2012). Dendritic cell apoptosis and the pathogenesis of dengue. Viruses, 4(11), 2736–2753. https://doi.org/10.3390/v4112736
  • Mota, J., & Rico-Hesse, R. (2011). Dengue virus tropism in humanized mice recapitulates human dengue fever. PloS One, 6(6), e20762. https://doi.org/10.1371/journal.pone.0020762.
  • Scott, T. W., & Morrison, A. C. (2010). Vector Dynamics and Transmission of Dengue Virus: Implications for Dengue Surveillance and Prevention Strategies BT  – Dengue Virus (A. L. Rothman (ed.); pp. 115–128). Springer Berlin Heidelberg. https://doi.org/10.1007/978-3-642-02215-9_9.
  • Weaver, S. C., Charlier, C., Vasilakis, N., & Lecuit, M. (2018). Zika, Chikungunya, and Other Emerging Vector-Borne Viral Diseases. Annual Review of Medicine, 69, 395–408. https://doi.org/10.1146/annurev-med-050715-105122

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