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Last year at least 3,500 cases were diagnosed in India and 49 people succumbed to the fever. Experts maintain that the outbreaks are related to rapid urbanization and lifestyle changes in addition to deficient water management and storage.
Dr. Duane Gubler, epidemiologist at the University of Hawaii, says that dengue fever is closely associated with population growth and urbanization. The rising number of dengue cases in the past decade in the big cities of India like Mumbai and Delhi substantiate this statement.
The past few years have witnessed a big boom in the construction industry in Mumbai and other cities. This has been an invitation for the migration of hundreds of workers from rural areas to the cities, and they have brought with them new strains of diseases.
The housing conditions of these migrant workers are very poor. Hundreds of them are concentrated in small living quarters without proper sanitation and hygiene. After rainfall, such areas are flooded with water and poor drainage leads to water accumulation. Vector control in the form of mass fumigation is inadequate. Such areas make excellent breeding grounds for mosquitoes.
There are four types of dengue viruses. The virus spreads when a mosquito bites an infected person and then bites another person. The viral infection gives rise to high fever, body ache, joint pains and bone pains. Usually the infection subsides by itself, and patients do not need any active treatment.
Rarely, the condition worsens into dengue hemorrhagic fever. In this condition the patient suffers from low platelet count. Platelets are a type of blood cells that prevent bleeding. When they decrease, the patient starts bleeding from various sites, with the slightest injury. This can be fatal if not diagnosed in time and due precautions are not taken. A blood transfusion might be required for such patients to raise the level of platelets.
Each year a high number of cases are diagnosed in leading cities in India like Mumbai and Delhi. Newer diagnostic kits enable physicians to accurately diagnose the condition. Ideally, there should be prompt notification of the health authorities after a case of dengue fever is diagnosed. This is necessary so that health authorities can initiate vector control measures and isolate the patient to prevent more mosquitoes from biting him and spreading the disease. This helps to prevent an outbreak from turning into an epidemic.
One problem is that patients might not present themselves for treatment at a hospital or health center. Occasionally, there might be failure of notification due to political pressures. Given these circumstances, it is even more difficult to contain the deadly disease. It is feared that the magnitude of the problem might be much greater than is assumed due to under representation of the population.
As of today there are no antiviral drugs available to actively treat the infection. In 2002, Swiss company Novartis and the Singapore Economic Development Board created the Novartis Institute for Tropical diseases to research neglected tropical diseases. This institute is now researching an antiviral drug to prevent dengue fever.
The Bill and Melinda Gates Foundation has made a generous donation toward the development of a pediatric dengue vaccine that will be affordable and accessible to poor children in endemic countries. Thai researchers are also testing a dengue fever vaccine.
Until the vaccines and antiviral drugs are available in the market, health authorities need to formulate strong strategies to tackle the growing problem of dengue fever. Health providers should be well trained to identify the symptoms of the illness at an early stage. The clinical management of cases should improve so that deaths due to dengue fever are reduced.
Also, in order to decrease the transmission of the disease, the poor and underprivileged population should be provided with clean living quarters with proper sanitation. They need to be educated about protecting themselves and their children from mosquito bites. Proper methods of storing water should be taught so that the mosquitoes do not breed freely.
Dengue fever is no longer a problem restricted to tropical countries. According to Dr. Shigeru Omi, the World Health Organization's regional director for the Western Pacific, and many other experts, global climate change is an important factor that is contributing to the increasing prevalence of the disease worldwide. A study by Dr. Simon Hales states that changes in the world temperature and rainfall will lead to an increase in the area of land with a climate suitable for dengue fever transmission, and if no other contributing factors change, a large proportion of the human population will be put at high risk of getting the disease.
According to the World Health Assembly, dengue prevalence has grown dramatically in recent years and the disease is now a major international public health concern. It strikes 50-100 million people each year, worldwide. Healthcare systems in India and the world over should address this fact and be ready with schemes to contain the outbreaks and prevent them from becoming an epidemic.
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(Dr. Pradnya Kulkarni is a clinical pathologist for a private laboratory in Pune, India.)
