VECTOR-BORNE DISEASES: DENGUE
Vector-borne diseases are human diseases caused by vector-borne diseases such as parasites,
viruses and bacteriai. More than 700,000 deaths a year are caused by malaria, dengue,
schistosomiasis, human African trypanosomiasis, leishmaniosis, chagas disease, yellow fever,
and onchocercoses. In tropical and subtropical countries, the widespread of these diseases
are greater, and it impacts the poorer people more. Since 2014, large epidemic outbreaks
reportedly affected people, claimed lives and disrupted health care services in many
countries: dengue, measles, chikungunya, yellow fever and Zika. Other diseases like
Chikungunya, leishmaniasis and filariasis cause chronic discomfort, lifetime morbidity,
incapacity and occasional stigma.
Dengue has recently been reclassified by the WHO (World Health Organization) due to issues
when applying the old clinical termsii. The latest recommendations focus on disease incidence
and cases are categorised as dengue, with no symptoms of warning on dengue and severe
cases of it. Severe dengue is characterised as extremely impacted patients with strong plasma
leaking, serious bleeding or organ involvement. The new classification system stresses that
possible signs should be identified early. Latest findings thus show a higher delicacy with the
revised classificationiii. In order to prevent hospitalizations in particular in hyperendemic
environments, early prediction is vital.
While there is no registered dengue vaccine yet, several vaccine potentials have been created.
Live attenuated virus vaccines, live chemistry, inactivated virus, live recombinant, DNA, or
sub-unit vaccines are all usediv. Live viral vaccinations were carried out in clinical trials, but
issues occured, such as uneven immunogenicity among four tetravalent formulations and
viral involvement among the four serotypes.
In conclusion, essential elements in the production of dengue vaccines include common
factors such as immunogenicity, reactogenicity and protective effectiveness. Ideally these
dimensions should be tempered by cost and stability considerations.
Referencing
i
CIESIN (Center for International Earth Science Information Network). Changes in the incidence of vector-borne
diseases attributable to climate change. 2007. http://www.ciesin.columbia.edu/TG/HH/veclev2.html.
ii
WHO (World Health Organization). Vector-borne diseases. Geneva: World Health Organization; 2020.
https://www.who.int/en/news-room/fact-sheets/detail/vector-borne-diseases
iii
Blaney JE Jr, Sathe NS, Hanson CT, Firestone CY, Murphy BR, Whitehead SS:Vaccine candidates for dengue virus
type 1 (DEN1) generated by replacement of the structural genes of rDEN4 and rDEN4Delta30 with those of
DEN1.Virol J2007,4:23.
iv
Sun W, Edelman R, Kanesa-Thasan N, Eckels KH, Putnak JR, King AD, HoungHS, Tang D, Scherer JM, Hoke CH Jr,
Innis BL:Vaccination of human volunteers with monovalent and tetravalent live-attenuated denguevaccine
candidates.Am J Trop Med Hyg2003,69:24–31.