Sri Lanka health officials have reported nearly 14,000 dengue through Apr. 18.

Aedes aegypti/CDC

The health districts accounting for the most of the 13,975 cases to date include Colombo (3126), Gampaha (1748) and Jaffna (1705).

At least 11 dengue-related fatalities have been reported.

Last year, Sri Lanka reported nearly 52,000 cases, following the epidemic of 186,000 in 2017, in which Dengue Fever Virus Type 2 (DEN-2) was the predominant strain.

Some experts in the country predict their may be an epidemic this year due to Dengue Fever Virus Type 3 (DEN-3).

In a Sunday Times report, Dr. LakKumar Fernando noted:

There are four dengue virus strains or serotypes (DENV1, DENV2, DENV3 and DENV4), he cites the example of Patient A coming down with DENV1. This patient would never get DENV1 again (having lifelong immunity). Patient A would also not get the other three (DENV2, DENV3 and DENV4) for a while – but that would be short-lived, only for a period of about six months to one year. Occasionally, this shorter immunity against the other strains may last for about two years.

However, here comes the “terrible” sting in the bite of the tiny dengue mosquito – the moment that short immunity wears off, if Patient A gets those strains, DENV2, DENV 3 or DENV 4, the virulence of that attack increases in leaps and bounds

This second attack of dengue is very likely to manifest in Patient A as Dengue Hemorrhagic Fever (DHF), warns Dr. Fernando.

Dengue infects nearly 400 million people across more than 120 countries each year. Most survive with few or no symptoms, but more than two million annually develop what can be a dangerous dengue hemorrhagic fever, which kills more than 25,000 people each year.

Dengue viruses are arboviruses (arthropod-borne virus) that are transmitted primarily to humans through the bite of an infected Aedes species mosquito.

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The spectrum of illness can range from a mild, non-specific febrile syndrome to classic dengue fever (DF), to the severe forms of the disease, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS):

  • Dengue Fever (DF) – marked by an onset of sudden high fever, severe headache, pain behind the eyes, and pain in muscles and joints. Some may also have a rash and varying degree of bleeding from various parts of the body (including nose, mouth and gums or skin bruising).Dengue has a wide spectrum of infection outcome (asymptomatic to symptomatic). Symptomatic illness can vary from dengue fever (DF) to the more serious dengue hemorrhagic fever (DHF).
  • Dengue Hemorrhagic Fever (DHF) – is a more severe form, seen only in a small proportion of those infected. DHF is a stereotypic illness characterized by 3 phases; febrile phase with high continuous fever usually lasting for less than 7 days; critical phase (plasma leaking) lasting 1-2 days usually apparent when fever comes down, leading to shock if not detected and treated early; convalescence phase lasting 2-5 days with improvement of appetite, bradycardia (slow heart rate), convalescent rash (white patches in red background), often accompanied by generalized itching (more intense in palms and soles), and diuresis (increase urine output).
  • Dengue Shock Syndrome (DSS) — Shock syndrome is a dangerous complication of dengue infection and is associated with high mortality. Severe dengue occurs as a result of secondary infection with a different virus serotype. Increased vascular permeability, together with myocardial dysfunction and dehydration, contribute to the development of shock, with resultant multiorgan failure.