The disease is endemic in more than 100 countries in the WHO regions of Africa, the Americas, the Eastern Mediterranean, South-East Asia and the Western Pacific. The America, South-East Asia and Western Pacific regions are the most seriously affected.

In the year 2015, According to National Vector Borne Disease Control Programme (NVBDCP) maximum numbers of cases were reported from Delhi followed by Punjab, Haryana, West Bengal, Gujarat , Karnataka, Maharashtra, Kerala, Tamil Nadu, Rajasthan, Andhra Pradesh, Uttar Pradesh, Orissa, Madhya Pradesh, Arunachal Pradesh, Bihar, Uttarakhand, Telangana and other states.

Symptoms usually develop within 3-14 days after being exposed to the dengue virus (also known as incubation period). The average incubation period is around 4-7 days.

Symptoms of dengue are:

1. Sudden-onset fever
2. Headache (typically located behind the eyes)
3. Muscle and joint pain
4. Rash
5. Chills (shivering)
6. Facial flushing
7. Loss of appetite
8. Sore throat
9. Abnormal bleeding such as nosebleeds, bleeding gums and/or blood in your urine.

10. Dengue virus is an RNA virus. Transmission of this virus occurs in a cycle. An infected human is bitten by a female mosquito. The infected mosquito then bites another human, and the cycle continues.

    MOSQUITO
    Aedes aegypti mosquitoes most commonly bite at dusk and dawn, indoors, in shady areas, or when the weather is cloudy. They can bite and spread infection at any time of day and all year long.
    The mosquitoes prefer to breed in areas of stagnant water, such as flower vases, uncovered barrels, buckets, water coolers and discarded tires. Some of the dangerous areas are wet floors and toilet tanks, as they allow the mosquitoes to breed in the residence.
    Although the lifespan of an adult A. aegypti is two to four weeks depending on conditions, the eggs can be viable for over a year in dry state. This allows the mosquito to reappear after a cold winter or dry spell.

    There are four serotypes of the virus that cause dengue (DEN-1, DEN-2, DEN-3 and DEN-4)

    Some facts about Ades mosquito-

    • Ae. aegypti is closely associated with human environments and can breed in indoor (flower vases, concrete water tanks in bathrooms), and artificial outdoor (vehicle tyres, water storage vessels, discarded containers) environments.
    • The eggs can survive up to 1 year without water. Once water is available (even small quantities of standing water), the eggs develop into larvae and then adult mosquitoes.
    • Aedes mosquitoes are active during daylight hours, and usually bite during the morning and late afternoon/evening hours.
    • Female Aedes mosquito acquires the virus while feeding on the blood of an infected person.
    • Female Aedes mosquito usually flies an average of 400 metres. But it may be transported accidently by humans from one place to another (e.g. in the back of the car, plants).

    References: 
    www.nhs.uk
    www.who.int
    A person with dengue may develop a severe and life threatening form of dengue known as dengue shock syndrome. This may be accompanied by a sudden and severe drop in blood pressure. Other symptoms of dengue shock syndrome are as follows:

11. • Cold, clammy skin
    • A weak rapid pulse
    • Dry mouth
    • Reduced flow of urine
    • Fast breathing

    The patients may seek medical advice immediately.

    Reference: www.nhs.uk