Times of India
19 July 2010
By Shailvee Sharda
Lucknow, India

A large number of dengue cases in the country could be going unreported. Reason being that they do not meet the criteria for various stages of dengue fever fixed by the World Health Organisation (WHO). Notably, figures from the National Vector Borne Diseases Control Programme website show that over 2,000 dengue cases were reported in the country between January and May this year.

Researchers from the postgraduate departments of microbiology, immunology, paediatrics and biotechnology at Chhatrapati Shahuji Maharaj Medical University (CSMMU), Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGIMS) and Baba Sahab Bhim Rao Ambedkar University have established that the WHO criteria for Dengue Haemorrhagic Fever (DHF) does not correctly classify all severe cases of dengue.

The finding– published recently in the Journal of Infection in developing countries– may be summed up as: “By using WHO criteria of dengue haemorrhagic fever (DHF) on Indian patients, all severe cases of dengue cannot be correctly classified. A new definition of DHF that considers geographic and age–related variations in laboratory and clinical parameters is urgently required.”

The study included 145 clinically suspected cases of dengue infection of all ages. Dengue was confirmed by serological methods which involve examining blood samples under a microscope. Clinical and laboratory parameters were compared between dengue patients with bleeding and those without bleeding.

The WHO criteria were applied to classify dengue positive patients into dengue fever (DF), Dengue Haemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS). Out of 50 serologically positive cases enrolled in the study, only three met the WHO criteria for DHF and one met the criteria for DSS. However, 42% cases had one or more bleeding manifestations.

When contacted, team leader and faculty with CSMMU’s microbiology department, Dr Prashant Gupta said, “If untreated, mortality from the complications is as high as 20% whereas if recognised early and managed properly, mortality is less than one per cent. Thus, it will be useful if certain symptoms, signs and laboratory parameters associated with the development of complications are identified so that such cases receive more attention.”

Sharing the credit with his teammates Vineeta Khare, Sanjeev Tripathi, Vijaya Lakshmi Nag, Rashmi Kumar, Mohammad Yahiya Khan and Tapan Kumar Nirod Chandra Dhole, he said there were certain limitations of the study. “The sample size was quite small and we need more detailed study to draw the attention of policy makers (on the issue),” he said.

Fast Facts

• Dengue virus spreads through female Aedes aegypti, also called tiger mosquito
• It breeds in clear water and most of the time bites during the day
• Dengue symptoms appear after 5–7 days of infected bite and the disease has a 15–day incubation period. Body temperature rises upto 104 degree followed by acute pain in the joints, muscles and headache. Rashes appear 3–4 days after fever and blood platelets count start decreasing. It is alarming when platelet count come below 10,000
• Dengue could be prevented by simple steps. Discard items that collect water especially old tires, evacuate water collected in air coolers, throw away the water that collects behind the refrigerator after defrosting it, do not store fresh water openly and avoid mosquito bits by using mosquito nets, repellents First, dengue fever in which people suffer from high temperature
• Second, which is also said to be a serious stage, patient suffers from dengue haemorrhagic fever (DHF) in which rashes develop on the body surface and there is possibility of bleeding
• Third stage is dengue shock syndrome (DSS), which is dreadful because there is possibility of circulatory failure