Dengue is caused by a virus of the Flaviviridae family and there are four distinct, but closely related, serotypes of the virus that cause dengue (DENV-1, DENV-2, DENV-3 and DENV-4). Recovery from infection is believed to provide lifelong immunity against that serotype. However, cross-immunity to the other serotypes after recovery is only partial, and temporary. Subsequent infections (secondary infection) by other serotypes increase the risk of developing severe dengue.
A patient enters what is called the critical phase normally about 3-7 days after illness onset. It is at this time, when the fever is dropping (below 38°C/100°F) in the patient, that warning signs associated with severe dengue can manifest. Severe dengue is a potentially fatal complication, due to plasma leaking, fluid accumulation, respiratory distress, severe bleeding, or organ impairment. Warning signs are severe abdominal pain, persistent vomiting, rapid breathing, bleeding gums, fatigue, restlessness, blood in vomit.
If patients manifest these symptoms during the critical phase, close observation for the next 24–48 hours is essential so that proper medical care can be provided, to avoid complications and risk of death.
Elderly patients with multiple comorbidities (medical conditions) are more likely to develop severe dengue.
There is no known cure for severe dengue. A person suffering from this form of dengue fever may need to be treated in an intensive care unit (ICU). Treatment will focus on the symptoms and includes the following: Blood and platelet transfusion, Intravenous fluids for rehydration, oxygen therapy if oxygen levels are low. With prompt treatment and care, a patient can recover even from severe dengue. However, if treatment is delayed and the patient develops shock or multi-organ failure, the fatality rate rises.
This year's dengue infection outbreak has been dreadful, and there have been several reports of infections taking a turn for the severe and high hospitalizations, with a newer, DENV-2 variant in circulation. Now, while dengue, which can present a lot of overlapping symptoms in common to infections like the flu or COVID, it is also an infection which should not be treated lightly, and can manifest complications, if the right treatment isn't followed. With the DENV-2 strain, said to be harsher on those who have battled dengue before, and/or have pre-existing illnesses, it's necessary that one remains careful, and any worsening symptoms be recognized at the earliest.
If you know you have dengue, avoid getting further mosquito bites during the first week of illness. Virus may be circulating in the blood during this time, and therefore you may transmit the virus to new uninfected mosquitoes, who may in turn infect other people.
The proximity of mosquito vector breeding sites to human habitation is a significant risk factor for dengue as well as for other diseases that Aedes mosquito transmit. At present, the main method to control or prevent the transmission of dengue virus is to combat the mosquito vectors.
As described in the WHO position paper on the Dengvaxia vaccine (September 2018) the live attenuated dengue vaccine CYD-TDV has been shown in clinical trials to be efficacious and safe in persons who have had a previous dengue virus infection (seropositive individuals). However, it carries an increased risk of severe dengue in those who experience their first natural dengue infection after vaccination (those who were seronegative at the time of vaccination).
(Dr Rommel Tickoo, Senior Consultant, Internal Medicine, Max Hospitals)
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