Dengue Fever (DF)Dengue fever is a viral infection transmitted by the female mosquito, for example, Aedes aegypti sp. and Aedes albopictus sp. It occurs in in tropical and sub-tropical regions around the world, predominantly in urban and semi-urban areas and usually increases in the hot and humid months. Dengue fever was discovered several hundred years ago. In recent years, dengue fever has become a major international public health concern. It is also known as breakbone fever as the dengue patients usually express contorted movements due to intense joint and muscle pain. Benjamin Rush from Philadelphia, US, first described "breakbone fever" in 1780. Slaves who developed dengue fever in the West Indies were said to have "dandy fever" because of their posture and gait. Dengue fever is caused by one of four different but related viruses. The dengue viruses form a distinct complex within the genus flavivirusbased on antigenic and biological characteristics. The four virus serotypes are designated as DEN-1, DEN-2, DEN-3 and DEN-4. Infection with any one serotype confers lifelong immunity to that virus serotype. Although all four serotypes are antigenically similar, they are different enough to elicit cross-protection for only a few months after infection by any one of them. These viruses are transmitted to humans (host) through the bites of the female Aedes mosquito (vector) as mentioned. This variety of mosquito breeds easily during the rainy seasons and even can flourish in peridomestic fresh water, for example, water that is stored in plastic bags, cans, flowerpots and old tires. Incubation period occurs when the virus has been transmitted to the human host. The period ranges from 3 to 15 days (usually lasting for 5-8 days) before the characteristics of dengue appear. During incubation time, the dengue virus multiplies.

The dengue virus travels to various glands in the body where it multiples. They then travel to the bloodstream, affecting some changes to these blood vessels. The viruses may cause the blood vessels to swell, leak and increased capillary permeability. This may result in fluid accumulation in the chest and abdominal cavity and leads to depletion of fluid from the circulation and decreased blood supply to vital organs. The spleen and lymph nodes may also become swollen (lymphadenopathy). Patches of liver tissue may die. Furthermore, a process known as disseminated intravascular coagulation (DIC) occurs. During this process, chemicals used to clot blood are used up, and thus severe bleeding (haemorrhage) occurs internally, typically the gastrointestinal tract and also the skin. This is critical phase, happen in some people which follows the resolution of the high fever and typically lasts one to two days after febrile phase. Basically, dengue commences with high fever (104 F, 40C), chills, headache, red eyes, pain in the eyes, vomiting, nausea, deep muscle and joint pains (during first hours of illness), loss of appetite, nausea and vomiting, low blood pressure and heart rate, extreme fatigue and other signs and symptoms for 2 to 4 days. This is febrile phase and it is associated with generalized pain. Then, the temperature drops rapidly and intense sweating takes place. After about a day with normal temperature and a feeling of well-being, the temperature rises abruptly again. Rashes (small red bumps) show up on the arms, legs and the entire body simultaneously along with fever. However, rashes rarely occur on the face. The palms of the hands and soles of the feet may be swollen and bright red. The patient may feel exhausted for several weeks. Most cases of dengue take approximately one week to recover. Once a person recovers from dengue, he or she will have antibodies in their bloodstream which will prevent them from having a relapse for about a year. However, during the absorption of the leaked fluid into the bloodstream, a fluid overload state may occur; if it affects the brain, it may cause a reduced level of consciousness or seizures.

Dengue fever is caused by virus. There is no specific medicine or antibiotic to treat it. For typical dengue fever, the treatment is purely concerned with relief of the symptoms. Medications are given to alleviate the signs and symptoms. Aspirin is not advisable to be taken as it will cause severe bleeding. Acetaminophen (Tylenol) is used to treat a high fever and Paracetamol can be taken to relieve muscle and joint aches, headache and fever. Bed rest is crucial to a speedy recovery and plenty of water has to be consumed to ease the illness. Instead of using ice water, it is required to sponge down with water at room temperature using a wet, squeezed out the towel for about 20 minutes at a time. This helps to lower the temperature. Dengue patients should be kept in a room that has screens or mosquito netting to prevent mosquitoes from entering until the second period of fever has subsided. If the patient is bitten, the dengue virus may be transmitted to the mosquito and then to another host. To avoid being bitten by mosquitoes that carry the virus, stay in air-conditioned or well-screened housing. Avoid being outdoors at dawn, dusk and early evening, when more mosquitoes are out. It is advisable to wear protective clothing like light coloured, loose and long-sleeved shirt and pants, socks and shoes. It is also sensible to use mosquito repellent. For instance, permethrin can be applied to clothing or shoes and 10 percent concentration of DEET (N, N-Diethyl-m-Toluamide) is applied to the skin. It is important to reduce the breeding habitat to lower mosquito populations. The mosquitoes that carry the dengue virus typically live in and around houses, breeding in standing water that can collect in such as used automobile tires, and containers. Flower pots, flower vases and ant traps are also common sources of mosquito breeding. They should be punctured to produce a drain hole. Implant practices of dispose solid waste properly and improve water storage, including covering containers to prevent access by egg-laying female mosquitoes. Besides, appropriate insecticides can be added to water containers and man-made ponds. The insecticides can prevent mosquitoes breeding for several weeks. However, they must be re-applied as per directions. Overall, dengue fever is caused by virus transmitted by female Aedes mosquito, intropical and sub-tropical regions and temperate areas of the world. It is also called as breakbone fever. The dengue virus travels to various glands in the body where it multiples through the bite of mosquito, and causes negative effects in human body. Three phases may happen, febrile phase, critical phase and recovery phase. During febrile phase, dengue commences with high fever, chills, headache, red eyes, muscle and joint pains and others. If these develop, it comes to critical phase, which the virus causes the blood vessels to swell and result in fluid accumulation in abdominal cavity. This leads to depletion of fluid from the circulation and decreased blood supply to vital organs. Lymphadenopathy and haemorrhage may occur. Recovery phase occurs next, which the patients will have antibodies in their bloodstream that will prevent them from having a relapse. There is no specific medicine or antibiotic to treat it as it is caused by virus. However, there are treatments and medications given to alleviate the signs and symptoms. Bed rest and plenty of water are crucial to dengue patients to ease the illness. To prevent being bitten by mosquitoes those carry the virus, stay in air conditioned or well-screened housing. Avoid being outdoors at dawn, dusk and early evening, when the mosquitoes are active. Wear protective clothing and apply mosquito repellent either on clothing or on skin. Take extra precautions to reduce mosquito-breeding sites around accommodations by emptying or covering any standing water. Insecticides can be added too. Although the government may have thermal fogging which is a kind of insecticide, from time to time, it is time consuming and expensive. In fact, the community is the key to dengue prevention. The main strategy in the prevention and control of dengue is "source reduction", or prevention of breeding places.

(1324 words)Referenceshttp://www.sristi.org/dmis/book/print/25http://www.mayoclinic.com/health/dengue-fever/DS01028/DSECTION=preventionhttp://www.medicinenet.com/dengue_fever/article.htmhttp://www.expat.com.my/dengue.htmhttp://www.who.int/mediacentre/factsheets/fs117/en/http://en.wikipedia.org/wiki/Dengue_feverhttp://www.nlm.nih.gov/medlineplus/ency/article/001374.htm