Dengue outbreaks in India: will history keep on repeating itself?

Dengue is caused by four flavivirus serotypes (DEN-1, DEN-2, DEN-3 and DEN-4). The incidence of dengue fever (DF) and dengue haemorrhagic fever (DHF) has increased thirtyfold globally in the last four decades. In developing nations like India, unplanned urbanization and migration of population from rural to urban areas with complete lack of proper sanitation facilities are important factors resulting in this situation. ‘Globalization’ with rapid air travel has also exposed the developed nations to this disease. The situation in our country is reflected by the occurrence of major disease outbreaks in India recent times. However, no reliable data are available to assess the magnitude of the disease in our country. But, obviously, the situation is quite dismal. In the last few years, many major disease outbreaks of dengue have been reported in India. The major pathophysiological abnormality differentiating DF from DHF is the plasma leakage syndrome due to generalized vasculopathy (haemoconcentration, hypo-protein aemia and/or serous effusion). The severity of disease in DHF depends on the quantum of plasma leakage. It is important to appreciate that platelet count is not predictive of haemorrhage. The patients of DHF with excessive plasma loss resulting in shock are labeled as dengue shock syndrome (DSS). DHF/ DSS are potentially fatal conditions if managed inappropriately. Therefore, there is a need to sensitize the health care providers regarding the management principles of DF/DHF. All patients of DF do not need hospitalization. Oral rehydration therapy should be initiated on the first day of the illness in DF as it prevents DHF and decreases risk for hospitalization in these patients. It will not be an exaggeration to state that appropriate hydration is the only therapeutic modality that makes the difference between life and death in a dengue patient. However, dengue patients with warning signs need to be hospitalized. The two most important warning signs which should never be ignored are inability to maintain hydration due to persistent vomiting or abdominal pain and haemetemesis or melaena. In our country with very poor oral dental hygiene in most people, gum bleeding may occur even with mild thrombocytopenia and needs to be considered in proper perspective rather than cause ‘panic’. The other warning sign is dizziness/vertigo on getting up from lying down position, reflecting postural hypotension. The role of platelet transfusion as a panacea for the management of dengue needs special mention. Unfortunately, patients as well as health care workers tend to “chase” platelet counts due to proliferation of “computerized laboratories” with automated ‘coulter’ machines which give almost instant platelet results. Often, the platelet count is underestimated by these computerized machines if they are not manually crosschecked due to the clumping of platelets. In fact, most of these patients are recovering from DF i.e., Patients are afebrile, appetite is normal and have a feeling of well being, but the platelet count is on the “lower side”. It needs to be re-emphasized that health care providers should not treat platelet count in dengue like ‘sensex’ of the share market i.e., An increase or decrease reflecting on the economy of the nation! The focus should be to treat excessive haemoconcentration by hydration and observe for overt bleeding (which is a danger sign irrespective of the platelet count). This “syndrome” of chasing platelet count in DF patients who are otherwise completely asymptomatic and improving can be labelled as “dengue panic syndrome”. Special Feature: Commentary Dengue outbreaks in India:will history keep on repeating itself?