Infection of the heart and acute liver failure are among the rarer complications.A pregnant woman who develops dengue is at higher risk of miscarriage, low birth weight birth, and premature birth. Cause
Virology
Dengue fever virus (DENV) is an RNA virus of the family Flaviviridae; genus Flavivirus. Other members of the same genus include yellow fever virus, West Nile virus, Zika virus, St. Louis encephalitis virus, Japanese encephalitis virus, tick-borne encephalitis virus, Kyasanur forest disease virus, and Omsk hemorrhagic fever virus. Most are transmitted by arthropods (mosquitos or ticks), and are therefore also referred to as arboviruses (arthropod-borne viruses).The dengue virus genome (genetic material) contains about 11,000 nucleotide bases, which code for the three different types of protein molecules (C, prM and E) that form the virus particle and seven other non-structural protein molecules (NS1, NS2a, NS2b, NS3, NS4a, NS4b, NS5) that are found in infected host cells only and are required for replication of the virus. There are five strains of the virus, called serotypes, of which the first four are referred to as DENV-1, DENV-2, DENV-3 and DENV-4. The fifth type was announced in 2013. The distinctions between the serotypes are based on their antigenicity. Transmission
Dengue virus is primarily transmitted by Aedes mosquitos, particularly A. aegypti. These mosquitos usually live between the latitudes of 35° North and 35° South below an elevation of 1,000 metres (3,300 ft). They typically bite during the early morning and in the evening, but they may bite and thus spread infection at any time of day.
People can prevent mosquito bites by wearing clothing that fully covers the skin, using mosquito netting while resting, and/or the application of insect repellent (DEET being the most effective). While these measures can be an effective means of reducing an individuals risk of exposure, they do little in terms of mitigating the frequency of outbreaks, which appear to be on the rise in some areas, probably due to urbanization increasing the habitat of A. aegypti. The range of the disease also appears to be expanding possibly due to climate change. Vaccine
In 2016 a partially effective vaccine for dengue fever became commercially available in the Philippines and Indonesia. It has been approved for use by Mexico, Brazil, El Salvador, Costa Rica, Singapore, Paraguay, much of Europe, and the United States. The vaccine is only recommended in individuals who have had a prior dengue infection or in populations where most (>80%) of people have been infected by age 9. In those who have not had a prior infection there is evidence it may worsen subsequent infections. For this reason Prescrire does not see it as suitable for wide scale immunization, even in areas where the disease is common.The vaccine is produced by Sanofi and goes by the brand name Dengvaxia. It is based on a weakened combination of the yellow fever virus and each of the four dengue serotypes. Studies of the vaccine found it was 66% effective and prevented more than 80 to 90% of severe cases. This is less than wished for by some.