Dengue Fever, Causes, Symptoms, Prevention, Treatment and Vaccine

Dengue Fever is a disease similar to malaria fever because is transmitted by mosquitoes. Their type is called Aedes. Even though this type of viral diseases is in the blood, people cannot pass it on directly to one another. Instead, it is transmitted by the insects.

Over the last 50 years, Dengue outbreaks have affected 22 different African countries. Around the world, the outbreaks of it include 100 million cases.

Since the disease is being transmitted by mosquitoes, the control of their population is one of the key prevention actions.

Dengue fever is a disease caused by a family of viruses that are transmitted by mosquitoes.

Dengue fever is a disease caused by a family of viruses transmitted by mosquitoes. It is an acute illness of sudden onset that usually follows a benign course with symptoms such as a headache, fever, exhaustion, severe muscle and joint pain, swollen lymph nodes (lymphadenopathy), and rash. The presence of fever, itchy rash and headache (the “dengue triad”) is characteristic of dengue. Other signs of dengue fever include gums bleeding, severe pain behind the eyes, and red palms and soles.

Dengue (pronounced DENG-gay) can affect anyone but tends to be more severe in people with compromised immune systems. Because it is caused by one of five serotypes of the dengue virus, it is possible to get dengue fever multiple times. However, an attack of dengue produces immunity for a lifetime to that particular viral serotype to which the patient was exposed.

Dengue goes by other names, including “breakbone fever” or “dandy fever.” Victims of dengue often have contortions due to the intense pain in the joints, muscles, and bones, hence the name breakbone fever. Slaves in the West Indies who contracted dengue were said to have dengue fever because of their postures and gait.

Dengue hemorrhagic fever is a more severe form of a viral illness. Symptoms include a headache, fever, rash, and evidence of bleeding (haemorrhage) in the body. Petechiae (small red spots or purple splotches or blisters under the skin), bleeding in the nose or gums, black stools, or easy bruising are all possible signs of haemorrhage. This form of dengue fever can be life-threatening and can progress to the most severe form of the illness, dengue shock syndrome.

Dengue fever starts with symptoms of chills, headache, pain in the back of the eyes that may worsen upon moving the eyes, appetite loss, feeling unwell (malaise), and low backache. Painful aching in the legs and joints occurs during the first hours of illness. The temperature rises quickly as high as 104 F (40 C), with relatively low heart rate (bradycardia) and low blood pressure (hypotension). The eyes become reddened. A flushing or pale pink rash comes over the face and then disappears. The lymph nodes in the neck and groin are often swollen.

High fever and other signs of dengue last for two to four days, followed by a rapid drop in body temperature (defervescence) with profuse sweating. This precedes a period with normal temperature and a sense of well-being that lasts about a day. A second rapid rise in temperature follows. A characteristic itchy rash (small red spots, called petechiae) appears along with the fever and spreads from the extremities to cover the entire body except for the face. The palms and soles may be bright red and swollen.

The transmission of the virus to mosquitoes must be interrupted to prevent the illness. To this end, patients are kept under mosquito netting until the second bout of fever is over and they are no longer able to transmit the virus to a biting mosquito.

The prevention of dengue fever requires control or eradication of the mosquitoes carrying the virus that causes dengue. In nations plagued by dengue fever, people are urged to empty stagnant water from old tires, trash cans, and flower pots. Governmental initiatives to decrease mosquitoes also help to keep the disease in check but have been poorly effective.

To prevent mosquito bites, wear long pants and long sleeves. For personal protection, use mosquito-repellant sprays that contain DEET when visiting places where dengue is endemic. There are no specific risk factors for contracting dengue fever except living in or traveling to an area where the mosquitoes and virus are endemic. Limiting exposure to mosquitoes by avoiding standing water and staying indoors for two hours after sunrise and before sunset will help, as the Aedes aegypti mosquito is a daytime biter with peak periods of biting around sunrise and sunset. It may bite at any time of the day and is often hidden inside homes or other dwellings, especially in urban areas.

Because dengue is caused by a virus, there are no specific antibiotics to treat it. Antiviral medications are also not indicated for dengue fever. For typical dengue, the treatment is concerned with the relief of the symptoms and signs. Home remedies such as rest and fluid intake (oral rehydration) are important. Pain relievers such as aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) should only be taken under a doctor’s supervision because of the possibility of worsening bleeding complications. Acetaminophen (Tylenol) and codeine may be given for a severe headache and for joint and muscle pain (myalgia).

Patients hospitalized for dengue may receive IV fluids.

Carica papaya leaf extract (papaya leaf) has been shown in several clinical studies to be an effective treatment for dengue fever.

In April 2016, the WHO approved Sanofi Pasteur’s Dengvaxia (CYD-TDV), a live recombinant tetravalent vaccine for dengue. Dengvaxia can be administered as a three-dose series in people 9-45 years of age who live in areas where dengue is endemic.

In clinical trials in Latin America and Asia involving more than 40,000 children and adolescents, Dengvaxia protected 66% of people aged 9 and older against dengue. Dengvaxia was very effective at protecting against severe dengue, which can be fatal, preventing 93% of severe cases, and reducing hospitalizations due to dengue by 80%.

Dengvaxia was initially approved in 2015 for use only in Mexico, the Philippines, Brazil, and El Salvador.

Several other vaccines for dengue are undergoing clinical trials, but none have yet been approved for use.

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Centres for Disease Control and Prevention

http://www.cdc.gov/Dengue/