Q&A WITH DR JUGAL KISHORE
*What is dengue fever?
Dengue fever is a viral disease caused by a virus called DENV which could be of four types namely DENV1 to DENV4. It is transmitted by the bite of the infected female Aedes mosquitoes.
*What are the symptoms of dengue fever?
Dengue fever symptoms are fever which can go up to 104 degrees F. Severe headache, pain behind the eyes, muscle and joint pains, nausea vomiting, and sometimes rashes.
*How is dengue fever caused and spread?
Bite of the infected mosquitoes mainly female Aedes aegypti and in some cases, albopictus transmit the dengue virus to new non-infected persons and cause disease. One such infected mosquito can transmit the infection to many persons and further transmit the dengue virus to new mosquitoes in a propagated manner. In a short period, a large number of persons get the infection which may cause an epidemic.
*What are the complications of dengue fever?
The majority of the time dengue is mild in nature but a small number of cases may be affected by complications and less than 1 percent may turn into deaths. Complications start 3-7 days after the onset of symptoms mainly after the fever subsides. Platelet counts start decreasing which resulted in plasma leakage, fluid accumulation, and bleeding. Therefore, bleeding from the nose or gum, blood in stool or vomitus, severe abdominal pain, respiratory distress, or subcutaneous bleeding appearing as petechiae are warning signs of fatality and should be managed at the hospital.
*How do you diagnose dengue fever?
Although clinical presentation is commonly picked up by doctors the diagnosis should always be made by the blood test to detect the virus, NS1 protein, or antibodies. When the Aedes mosquito population is high, particularly in the rainy season any fever should be suspected and a blood test for dengue should be done.
*How do you treat dengue fever?
As we don't have any drugs against dengue viruses, symptomatic treatment is the only solution. For fever, cold sponging and paracetamol are advised. Aspirin or its derivative drugs are contraindicated as they cause inhibition of platelet functions. It is better to get the advice of your family doctor in case of suspicion of dengue. The first dengue vaccine, Dengvaxia( CYD-TDV) has been approved for human use and is commercially available in India. It can be used in those who have previously been infected with dengue fever at least once.
*How do you prevent dengue fever?
As we know that prevention is better than cure, preventive measures, particularly against mosquitoes are best. Breeding of mosquitoes occurs in water accumulated in any storage anywhere extending from large water bodies to a small bucket, mud pot, discarded containers, used tyres, rooftop water tank, container, flower pot, leave, plastics, cistern, tree, etc. Once a female has laid her eggs, these eggs can remain viable for several months in dry conditions and will hatch when they are in contact with water. All such breeding sites need to be eliminated by physical and engineering methods. Larva, pupas, and mosquitoes can be killed by various environment-friendly insecticides. This mosquito is usually a day-biter. Bites of mosquito can be prevented by covering body parts with appropriate cloths, using repellents and mosquito bed nets. Housing windows should be covered with wire mesh.
*Which type of doctor should one consult for dengue fever?
General physicians may be consulted for dengue fever. However, specialists are required when complications set in.
*Can I be infected with dengue a second or more times?
Yes, dengue can occur a minimum of 4 times due to the presence of 4 types of dengue viruses.
*What kind of mosquito repellents are safe?
Picaridin is a good alternative to DEET because it is just as effective at repelling mosquitoes but is not harmful to the environment. Oil of lemon eucalyptus is also effective, but it is not as long-lasting.
*Is dengue becoming resistant to household repellents?
There are few results on resistance to household repellents. However, all living organisms try to protect their survival by changing their genetic makeup. There are many natural repellents such as citronella, lemongrass, and marigold plants that have mosquito repellent activities if they are kept in and around the house but it should be remembered that they should not be holding water which can be a potential site of breeding.
*Is the number of dengue cases on the increase?
Dengue fever has increased in recent decades due to unregulated urbanization, population mobilization, and climatic changes.
(Dr Jugal Kishore is Director Professor and Head of Community Medicine Department at Safdarjung Hospital, New Delhi)