LAHORE - People affected by Dengue previously are at greater risk of getting complications if exposed to the vector borne disease again due to circulation of different serotype this year, medical experts say.

In Lahore, Dengue virus has affected more than 60,000 people since first outbreak of the much feared disease in 2006. The deadly disease took at least 400 lives in 2011 after affecting more than 22,000 people. Majority of the patients are previously affected by serotype two or three, and as such they are immune against the specific strain for lifetime. But they are not immune against the other serotypes.

“There are four serotypes of Dengue virus, I, II, III and IV. Recently fifth serotype has been reported but it has not affected Pakistan yet. People affected by dengue develop lifetime immunity against the specific serotype. If affected by the same serotype for the second time, people will not develop dengue. But if exposed to different serotype for the second time, they are at huge risk of developing complications”, said Dr Abdul Rauf, leading family physician who receive dozens of dengue patients daily in peak season.

“Previously, most of the patients in Lahore are affected by Dengue-III. About half of the patients this year are affected by serotype-I. As such different strains of Dengue virus are circulating in Lahore this year. The people who get Dengue previously believe that they are immune and as such could not get the disease for the second time. But in reality they needed extra care as exposure to other serotype could cause complications including life threatening Dengue Hemorrhagic Fever (DHF) or Dengue Shock Syndrome (DSS),” he said.

Dr Abdul Rauf added: “First time exposure to any serotype causes Dengue fever. Symptoms begin three to fourteen days after infection. This may include a high fever, headache, vomiting, muscle and joint pains, and a characteristic skin rash. Recovery generally takes two to seven days.

“In some cases, the disease develops into DHF, resulting in bleeding, low levels of blood platelets and blood plasma leakage. The other severe condition is DSS, where dangerously low blood pressure occurs.”

Subsequent infection with a different type increases the risk of severe complications like DHF or DSS, he further informed.

Executive District Officer Health Dr Zulfiqar Ahmed confirmed circulation of different serotypes of Dengue virus this year, saying it was due to movement of patients from other cities to Lahore.

“Different serotypes of Dengue virus were affecting different areas. People in Lahore were mostly affected by serotype III or IV in previous years. Serotype I was prevalent in Rawalpindi and adjoining areas. Now this strain (serotype I) is affecting Lahore. About half of the patients reported this year are carrying Dengue virus serotype-I,” he said.

“People affected by Dengue previously need to take extra care to avoid second time exposure to different serotype as it could cause complications. Though different strains are circulating, no patient with severe complications has been reported so far. This is all due to public awareness, better understanding of healthcare providers about the disease and proper patient management at hospitals,” the EDO Health added.

He also urged taking precautionary measures to defeat Dengue in the wake of circulation of different strains of virus.

Prevention is eliminating mosquito habitat and limiting exposure to bites. Precautions are getting rid of or covering standing water and wearing full sleeve clothing. Treatment of acute dengue is giving fluid either by mouth or intravenously. In some cases blood transfusion may be required.