DEN-2 (dengue strain type-two) — the more virulent of the four serotypes of dengue — is in circulation this year in the Capital along with DEN-4, according to a preliminary report by the All India Institute of Medical Sciences (AIIMS) released on Friday.
Delhi has previously seen all four serotypes (1, 2, 3 and 4) of dengue, which have been isolated from time to time.
“This year DEN-2 is most predominant along with DEN-4, which we haven’t seen predominantly in Delhi. Usually when a person gets a particular strain of dengue he gets some immunity against it. This year we are seeing larger number of people coming in with DEN-2 infection,” said AIIMS Professor, Department of Microbiology, Lalit Dar.
“DEN-2 is the more virulent type of dengue and the symptoms are more severe. However, having said that it is important to tell the general public that dengue is completely treatable in 99 per cent cases and patients with symptoms should seek medical help immediately. This is no cause for worry,” he added.
Meanwhile, a report issued by AIIMS has noted that its virology laboratory has already generated preliminary data on the serotype of dengue circulating in Delhi in the on-going season.
“There appears to be a co-circulation of dengue serotypes 2 and 4 (DEN-2 and DEN-4) this year. Dengue virus has been isolated from six of the nine samples tested and of this four samples had DEN-2 and two samples had DEN-4. DEN-2 has been predominantly isolated in the last two years and DEN-4 has been isolated very rarely in previous years too. The Institute has tested 738 samples so far using the IgM antibodies and NSI antigen and 341 tested positive for dengue,” noted a senior AIIMS official.
“In 2010, when the last dengue surge was registered in Delhi, the city saw all the strains of dengue with DEN-2 being predominant,’’ said AIIMS spokesperson Amit Gupta.
Stating that dengue is both preventable and manageable, K.K. Aggarwal of the Indian Medical Association said: “The risk of complications is in less than one per cent of dengue cases and, if warning signals are known to the public, all deaths from dengue can be avoided. A platelet transfusion is not needed if the platelet counts are more than 10,000. Unnecessary platelet transfusion can cause more harm than good.”
Most dengue virus infections in adults are symptomatic (86 per cent) and in children under the age of 15 years are asymptomatic or minimally symptomatic.
Classic dengue fever is an acute febrile illness accompanied by headache, retro orbital pain, and marked muscle and joint pains. Symptoms typically develop between four and seven days after the bite of an infected mosquito. The incubation period may range from three to 14 days. Fever typically lasts for five to seven days. The febrile period may also be followed by a period of marked fatigue that can last for days to weeks, especially in adults. Joint pain, body aches, and rash are more common in females.
He added that most complications of dengue occur after the fever is over. The two days after the last episode of the fever are crucial and during this period, a patient should be encouraged to take plenty of oral fluids mixed with salt and sugar.
“The main complication is leakage of capillaries and collection of blood outside the blood channels leading to intravascular dehydration. Giving fluids orally or by intravenous routes, if given at a proper time, can save fatal complications,” he added.
