What is Dengue?

Dengue is the most widespread mosquito-borne infection in human beings, which in recent years has become a major international public health concern. Over the last 15 years, we have witnessed a dramatic increase in the global incidence of dengue and its severe manifestations such as dengue hemorrhagic fever.
Dengue fever is a severe, flu-like illness with fever, headache and muscle and joint pains that affects children and adults, but seldom causes death.
Dengue hemorrhagic fever (DHF) is a potentially deadly complication in about 1-3% of cases that begins with a sudden rise in temperature which usually continues for two to seven days and can be as high as 40-41°C. In moderate DHF cases, all signs and symptoms abate after the fever subside. In severe cases, the patient's condition may suddenly deteriorate after a few days of fever when the temperature drops, followed by signs of circulatory failure. With modern intensive supportive therapy, the fatality rates can be reduced to less than 1%.

How is Dengue spread?

Dengue is spread through the bite of an infected Aedes Aegypti mosquito. The mosquito gets the virus by biting an infected person. The first symptoms of the disease occur about 5-7 days after the infected bite. There is no way to tell if a mosquito is carrying the Dengue virus. Therefore, people must protect themselves from all mosquito bites.

How can we prevent Dengue?

Prevent mosquito bites
o Dengue mosquitoes bite during the daytime - protect yourself from the bite.
o Wear full-sleeve clothes and long dresses to cover the limbs. Avoid wearing black color.
o Use repellents. Care should be taken in using repellents on very young children or the elderly
o Use mosquito coils and electric vapor mats during the daytime to prevent mosquito bites
o Use insecticide treated nets (ITNs) to protect young children, pregnant women, old people, in addition to others who may rest during the day.
o Curtains (cloth or bamboo) can also be treated with insecticide and hung at windows or doorways, to repel or kill mosquitoes.

Where do mosquitoes live and breed?

Dengue mosquitoes breed in stored, exposed, water collection systems. The favoured breeding places are: barrels, drums, jars, pots, buckets, flower vases, plant saucers, tanks, discarded bottles/tins, tyres, or water coolers, and other places where rainwater collects or is stored. The mosquito eggs become adults in about 10 days.
o Drain out the water from window air coolers when not in use, as well as draining all unused tanks, barrels, drums, and buckets.
o Remove all objects containing water such as plant saucers from the house.
o All stored water containers should be kept covered at all times.
o Collect and destroy discarded containers in which water collects, such as bottles, plastic bags, tins, tyres, etc.
o Efficient disposal of all solid waste/garbage.

How should we take care of a Dengue patient?

• Keep body temperature below 39oC. Give the patient paracetamol (not more than four times in 24 hours). Fever can also be reduced by sponging patient with tepid water.
• Do not give the patient Aspirin or Ibuprofen (Brufen) or similar medicine for fever or pain. Give only paracetamol.
• Give large amounts of fluids (water, soups, milk and juices) along with the patient’s normal diet
• The patient should rest
• Immediately consult your physician if any of the following manifestations appear: Red spots or points on the skin; bleeding from the nose or gums; frequent vomiting; vomiting with blood; black stools; sleepiness; constant crying; abdominal pain; excessive thirst (dry mouth); pale, cold or clammy skin; or difficulty in breathing.
25 October 2010

Introduction
Dengue fever also known as breakbone fever, is an infectious tropical disease caused by the dengue virus. Symptoms include fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles. In a small proportion of cases the disease develops into the life-threatening dengue hemorrhagic fever, resulting in bleeding, low levels of blood platelets and blood plasma leakage, or into dengue shock syndrome, where dangerously low blood pressure occurs.
Dengue is transmitted by several species of mosquito .The virus has four different types; infection with one type usually gives lifelong immunity to that type, but only short-term immunity to the others. Subsequent infection with a different type increases the risk of severe complications. As there is no vaccine, prevention is sought by reducing the habitat and the number of mosquitoes and limiting exposure to bites.
Treatment of acute dengue is supportive, using either oral or intravenous rehydration for mild or moderate disease, and intravenous fluids and blood transfusion for more severe cases. The incidence of dengue fever has increased dramatically since the 1960s, with around 50–100 million people infected yearly. Early descriptions of the condition date from 1779, and its viral cause and the transmission were elucidated in the early 20th century. Dengue has become a worldwide problem since the Second World War and is endemic in more than 110 countries. Apart from eliminating the mosquitoes, work is ongoing on a vaccine, as well as medication targeted directly at the virus.

Signs and symptoms
Typically, people infected with dengue virus are asymptomatic (80%) or only have mild symptoms such as an uncomplicated fever. Others have more severe illness (5%), and in a small proportion it is life-threatening. The incubation period (time between exposure and onset of symptoms) ranges from 3–14 days, but most often it is 4–7 days. Therefore, travelers returning from endemic areas are unlikely to have dengue if fever or other symptoms start more than 14 days after arriving home. Children often experience symptoms similar to those of the common cold and gastroenteritis (vomiting and diarrhea), but are more susceptible to the severe complications.

Transmission
Dengue virus is primarily transmitted by Aedes mosquitoes, particularly A. aegypti. These mosquitoes usually live between the latitudes of 35° North and 35° South below an elevation of 1,000 metres (3,300 ft). They bite primarily during the day. Humans are the primary host of the virus, but it also circulates in nonhuman primates. An infection can be acquired via a single bite. A female mosquito that takes a blood meal from a person infected with dengue fever becomes itself infected with the virus in the cells lining its gut. About 8–10 days later, the virus spreads to other tissues including the mosquito's salivary glands and is subsequently released into its saliva. The virus seems to have no detrimental effect on the mosquito, which remains infected for life. Aedes aegypti prefers to lay its eggs in artificial water containers, to live in close proximity to humans, and to feed off people rather than other vertebrates.

Mechanism
When a mosquito carrying dengue virus bites a person, the virus enters the skin together with the mosquito's saliva. It binds to and enters white blood cells, and reproduces inside the cells while they move throughout the body. The white blood cells respond by producing a number of signaling proteins, such as interferon, which are responsible for many of the symptoms, such as the fever, the flu-like symptoms and the severe pains. In severe infection, the virus production inside the body is greatly increased, and many more organs (such as the liver and the bone marrow) can be affected, and fluid from the bloodstream leaks through the wall of small blood vessels into body cavities. As a result, less blood circulates in the blood vessels, and the blood pressure becomes so low that it cannot supply sufficient blood to vital organs. Furthermore, dysfunction of the bone marrow leads to reduced numbers of platelets, which are necessary for effective blood clotting; this increases the risk of bleeding, the other major complication of dengue fever.

Prevention
There are no approved vaccines for the dengue virus. Prevention thus depends on control of and protection from the bites of the mosquito that transmits it. The World Health Organization recommends an Integrated Vector Control program consisting of five elements:
(1) Advocacy, social mobilization and legislation to ensure that public health bodies and communities are strengthened,
(2) collaboration between the health and other sectors (public and private),
(3) an integrated approach to disease control to maximize use of resources,
(4) evidence-based decision making to ensure any interventions are targeted appropriately and (5) capacity-building to ensure an adequate response to the local situation.
The primary method of controlling A. aegypti is by eliminating its habitats. This is done by emptying containers of water or by adding insecticides or biological control agents to these areas, although spraying with organophosphate or pyrethroid insecticides is not thought to be effective.[3] Reducing open collections of water through environmental modification is the preferred method of control, given the concerns of negative health effect from insecticides and greater logistical difficulties with control agents. People can prevent mosquito bites by wearing clothing that fully covers the skin, using mosquito netting while resting, and/or the application of insect repellent (DEET being the most effective).

source: Wikipedia

Dengue Fever
The virus that causes dengue fever is carried by female mosquitoes "Aides Aegypti", it normally feeds during the daytime, and is transmit their virus to humans through their bite. It is more likely to occur during or after the rainy season. Dengue fever can occur to people of all ages but it mostly affects children under the age of 15 years, but can occur in all age groups. Avoiding mosquito bites during the day time is a critical precautionary measure. Infection with one dengue serotype provides lifelong immunity but each individual can eventually be infected by other 3 serotypes. Several serotypes can be in circulation during an epidemic. The virus of the mosquitoes is not contagious and cannot be spread directly from person to person. There must be a person-to-mosquito-to-another-person pathway.

Other Names of Dengue Fever are: Dandy fever, Three-day fever, Breakbone fever. It is called as Breakbone Fever because the Victims of dengue often have contortions due to the intense joint and muscle pain, hence it has named as breakbone fever.

Dengue is prevalent throughout the tropics and subtropics. Outbreaks have occurred in the Caribbean, including Puerto Rico, the U.S. Virgin Islands, Cuba, and Central America. Cases have also been imported via tourists returning from areas with widespread dengue, including Tahiti, the South Pacific, Southeast Asia, the West Indies, India, and the Middle East.

Ayurvedic Name of Dengue Fever is "Dandak Jwara"

Causes of Dengue Fever :

Increase in non-biodegradable plastic packaging and discarded tires
Increased jet air travel is helping people infected with dengue viruses to move easily from city to city.
Lack of effective methods to control epidemics
Lack of effective mosquito control efforts
Poor Public health systems
Rapid growth or Overcrowding of cities in tropical countries
Urban decay, and substandard sanitation, allowing more mosquitoes to live closer to more people.
Signs & Symptoms of Dengue Fever

The time between the bite of a mosquito carrying dengue virus and the start of symptoms averages 5 to 7 days, with a range of 3 to 14 days. An infected person cannot spread the infection to other persons but can be a source of dengue virus for mosquitoes for about 6 days. When mosquitoes bite an infected person and then it bites another person then the virus is transmitted to one person to another. There are several signs and symptoms of dengue, some of them are as follows:

Signs & Symptoms of dengue include:

Chills
Flushed face
Increase in temperature, a rash, and a headache.
The rash consists of small red bumps that begin on the arms and legs, but then spread to the back, abdomen, and chest.
Lower back pain and general weakness.
Red eyes and eye pain
Severe joint and muscle pain
Swollen lymph nodes
Soles of the feet and palms of the hands also turn red and swell.
These symptoms last for two to three days. Afterward, the fever drops and the patient experiences heavy sweat, but feel better for around one day.

In more severe cases, patients have fever and headache, and then develop a cough. The dengue virus causes the blood vessels to swell and leak, creating small purple colored spots on the skin, called petechiae. The skin may appear bruised in areas where the bleeding is worse. Bleeding into the stomach causes severe abdominal pains and vomiting of a black, grainy substance that looks like coffee grounds. The damaged blood vessels eventually become so large that they are unable to supply the needed blood flow and the oxygen it carries to the body's tissues. This causes the body to go into shock, and can damage major organs such as the heart and kidneys.

Dengue hemorrhagic fever (DHF) or Dengue shock syndrome (DSS)
Dengue hemorrhagic fever is a life threatening complication that is characterized by high fever, hemorrhagic (bleeding) phenomena - often with enlargement of the liver and in severe cases circulatory failure. The illness commonly begins with a sudden rise in temperature accompanied by facial flush and other symptoms of dengue fever. The fever usually continues for two to seven days and can be as high as 40-41°C, (104 to 106 degree Fahrenheit). Mostly the severe cases of dengue hemorrhagic fever occur in children.

Symptoms of Dengue Hemorrhagic Fever

Persistent red spot on the skin or in the nose, bleeding gums, 'coffee- ground '. vomit or dark stools
The child remains ill despite fall in temperature, and develops cold and sweaty extremities such as hand and feet, clammy skin, restlessness or drowsiness

Diagnosis of Dengue Fever
Diagnosis is made on the basis of clinical symptoms and blood test. The earlier detection is the only cure for this illness.


Treatments of Dengue Fever

Dengue fever is usually a self-limited illness, and only supportive care is required. Paracetamol may be used to treat patients with symptomatic fever.
Keep up oral intake, especially of oral fluids and/or, oral rehydration salts to prevent dehydration.
Aspirin and nonsteroidal anti-inflammatory drugs (e.g. ibuprofen, diclofenac) and corticosteroids should be avoided.
During Dengue platelet count in the blood goes down. Since medicines like aspirin reduce platelet count, they should be avoided.
If symptoms of Dengue hemorrhagic fever are seen immediately report to your doctor or visit to the hospital for treatment.

Because dengue is caused by a virus, there is no specific medicine or antibiotic to treat it. For typical dengue, the treatment is purely concerned with relief of the symptoms. Rest and fluid intake for adequate hydration is important.

Preventions of Dengue Fever
At present, the only method of controlling or preventing dengue and DHF is to combat the mosquitoes. Aedes aegypti breeds primarily in man-made containers like earthenware jars, metal drums and concrete cisterns used for domestic water storage, as well as discarded plastic food containers, used automobile tyres and other items that collect rainwater. Discard or dry these items.

Avoid heavily populated residential areas.
Avoid mosquito bite even during day time.
Discard items that can collect rain or run-off water, especially old tires.
Eliminate mosquito breeding sites around homes.
Regularly change the water in outdoor bird baths and pet and animal water containers.
Sleeping area should have mosquito netting over the bed.
Stay in well-screened areas.
Use long clothes to cover the body to avoid mosquito bite
Use mosquito repellents on skin and clothing.
When indoors, stay in air-conditioned or screened areas. Use bednets if sleeping areas are not screened or air-conditioned.
When outdoors during times that mosquitoes are biting, wear long-sleeved shirts and long pants tucked into socks.