Dengue is a viral disease which is highly prevalent in tropical countries like India. This viral disease is dreaded in the population because of the small creatures which carry the virus causing the disease, the mosquito. Specifically, the species Aedes aegypti and to a lesser extent A. albopictus transmit the virus. These species also spread chikungunya, yellow fever and Zika; however, dengue is the most important disease in the tropics.
The disease was first recognized in its severe form in the 1950s during the dengue epidemics in the Philippines and Thailand. In India, the first major outbreak of the severe form was seen in 1963 in Calcutta. Since then, occurrence of the disease has increased in the country. India is almost endemic for the disease and cases are reported every year with a doubling in 2014-2016; with over 15,000 cases in Delhi alone in 2015
The disease occurs in two forms – Dengue fever and Dengue Hemorrhagic Fever. Dengue fever is characterized with severe flu like symptoms and dengue hemorrhagic fever is a more severe form of the disease with hemorrhage or bleeding and shock seen in many cases. Recovery from the disease does not ensure immunity from the disease.
The mosquito acquires the virus while feeding on the blood of an infected person and transmits it to a healthy person through a bite and the virus multiplies in the person’s body. The virus requires an incubation period of 8 to 10 days. The infected mosquitoes are capable of transmitting the disease to susceptible individuals for the rest of its life, i.e. 3 weeks. Humans are the main amplifying host of the virus but in some part of the world, monkeys may become infected and serve as a source of virus. The virus circulates in the blood of the infected person for 2 to 7 days.
Usually urban areas are at higher risk due to high population density poor sanitation etc. which promotes breeding. The disease can also occur in rural areas where the environment is suitable for mosquito breeding like water tanks for cattle feeding and drinking, discarded things and bottle etc. The outbreak of disease can mostly occurs in areas with high stray monkey population like in many Indian cities. The disease is most likely to occur in post-monsoon period when the breeding of mosquitoes is high.
The first sign is an abrupt onset of high fever, severe headache, pain behind the eyes which worsens eye movement and muscles and joint pain. This is followed by a loss of appetite, weakness, emaciation, nausea and vomiting. Raresymptoms are measles-like rash over chest and upper limbs. Dengue hemorrhagic fever is a severe form of the disease which may lead to dengue shock syndrome which can cause death.Dengue fever is self-limiting if the viral load is low but may cause death if it is high.
In case of dengue fever,there is no absolute cure, rather a symptomatic treatment is followed which include bed rest, antipyretic and analgesic with antibiotic treatment in some cases. Electrolyte solutions are recommended for patient with excessive sweating, nausea, vomiting or diarrhea to prevent dehydration. The treatment of dengue hemorrhagic fever, however, is difficult with early phase treatment similar to dengue fever. A patient with showing symptoms of DHF should be immediately admitted to appropriate standardized clinical treatment in hospital to reduce mortality rate.
There is no effective vaccine available for dengue. However there are several preventive measures to prevent the spread of mosquitoes and incidence of bite. We should ensure that tank and cooler have tight fitting leads. Water should not be store in containers without a proper lead. Make sure that stagnant water is not present in garbage dumb around the premises. Any pond, fountain etc. for ornamental purposes should be maintained properly with the water being drain regularly. Small fishes can be introduced in the water bodies to eat up the larvae of the mosquitoes. All possible mosquito breeding sites should be detected and eliminated and if the sources of mosquito are not controlled, the Zonal Health Municipal authorities should be contacted immediately. In order to reduce incidence of bites, mosquito repellent sprays, creams and mats can be used. Wearing of full sleeve shirts and pants can reduce bites during the monsoons. Bed nets during the night can also be very helpful in areas with high prevalence of mosquitos.
Dengue is a disease which has been to some extent successfully controlled by urban cities in India. Yet, some semi urban and rural places still suffer from sporadic cases of the diseases due to lack of health facilities, knowledge and education of the disease. Various mosquito repellents and insecticide are produced to target dengue and this helps in the control of the disease. Dengue is a dreaded nuisance to public and individual health and it is difficult to eradicate. But, control of vectors and sanitation of the environment can greatly reduce outbreaks and cases in the country. If any of you reading this possess one or more of the above symptoms, please contact your nearest doctor immediately.
