Dengue & Its Threat In India
Dengue is one of the most common and significant viral illnesses spread by mosquitoes across the world. Seen more often in tropical regions, it is transmitted by Aedes mosquitoes (day-biting) who acquire the infection by biting an infected person and passing it onwards. The threat of this disease covers almost half the world’s population and in the past few years, the incidence of dengue has seen a rise even in countries with a more temperate climate. Although considered a self-limiting disease, the mortality rate for dengue can vary widely from 2-20 per cent, depending upon the time to diagnosis and initiation of treatment.
There are 4 serotypes of dengue and some of those who get reinfected with a different serotype may encounter more serious complications like hemorrhagic fever (where bleeding is commonly seen) and dengue shock syndrome. Once a person is infected with a serotype, immunity develops against that serotype but other serotypes can still cause an infection.
The incubation period for dengue is between 4-10 days which means for the first 4 days there may be no symptoms. When symptoms do manifest, they present as fever with or without chills, skin rash and the face may appear flushed.
Anybody presenting with a high grade fever (104o F) accompanied by a headache starting at the back of the eyes, muscle and joint pain, nausea, vomiting etc. with a history of travel to an area where dengue is prevalent could be a suspected case.
Other signs and symptoms may include small areas of bruising (bleeding under the skin), anorexia, lymph node enlargement. The bruising happens because of a decline in the platelet count as a drop in platelets means a reduced ability of the blood to clot in time. Also, as mentioned earlier, bleeding from other sites like gums, gastrointestinal tract etc. is seen in case of hemorrhagic fever and could be fatal if not diagnosed and treated in time.
Apart from a thorough history, the diagnosis of dengue is guided by serological tests which demonstrate a 4-fold increase in immunoglobulins. Other tests include dengue antigen determination from blood samples. Along with these, it is critical to perform a complete blood count that includes platelet estimation. A platelet level below 100k is considered abnormal. Platelet estimation needs to be repeated daily from day 3 of the illness and should continue till recovery.
The treatment of dengue is limited by the fact that there is no specific antiviral drug available. Supportive treatment forms the mainstay of management. Oral rehydration therapy to prevent dehydration due to vomiting and diarrhoea is recommended. Patients showing more severe symptoms including those with suspected haemorrhagic fever should be treated in a hospital for aggressive fluid management.
Children usually present with milder symptoms but elderly dengue patients may present atypically and are at higher risk of DHF, SD and HAI. Aside from dengue severity, age, and co-morbidity are associated with a longer hospital stay. Recovery is gradual and patients are encouraged to resume activities over a period of time. This may have implications for the working population and could be a concern for employers already facing increased absenteeism due to long COVID-19. It is essential for employers to conduct workplace health risk assessments and put into place infection control and management strategies.
There have been reports of co-infection with dengue and COVID-19 in tropical regions. The symptoms of both diseases overlap and can mislead clinicians unless an accurate diagnosis is made to better guide clinical management. The only way to actually prevent dengue is to avoid being bitten by mosquitoes carrying the virus. Since travel cannot really be restricted to dengue endemic areas, other strategies need to be adopted by governments, health authorities and individuals, acting in a synergistic manner. These include:
Increased surveillance for early identification of outbreaks
Heightened public awareness through dedicated campaigns
Regular spraying / fogging of mosquito breeding areas with insecticides/larvicides to kill mosquito larvae
Ensuring that water does not collect in areas where flooding and stagnation of water is known to happen
Use of protective / barrier clothing, along with repellents
Trousers and long-sleeved tops are recommended
Using mosquito-repellent sprays in indoor areas
Avoiding outdoor exposure as much as possible
A vaccine for dengue has been developed but its use is limited to those who have already been infected once and are at high risk for reinfection. As such this vaccine is not universally available for general use. Dengue is a growing threat and it is essential in a post-pandemic world to spread early awareness and guide appropriate action towards such emerging health threats to prevent larger scale disease outbreaks which could be detrimental to human health across the world. Staying informed is not only the first but possibly the most critical step.
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