The Origins of Dengue Fever and The Effects

Dengue fever also known as breakbone fever is a mosquito-borne disease caused by the dengue virus. Dengue is found in tropical and sub-tropical areas of the world. There are four Dengue viruses that can cause dengue fever that is classified as DENV. The CDC states that the make-up of the virus is, “a single-stranded RNA viruses that belong to the family Flaviviridae and the genus Flavivirus—a family which includes other medically important vector-borne viruses” (CDC 2012). The Flaviviridae family are the notorious vector born viruses including West Nile and Zika. The illness causes flu-like symptoms but in severe cases can develop Dengue shock syndrome (DSS) or Dengue hemorrhagic fever (DHF). There is not a vaccine to prevent dengue yet, the most effective way to not get the virus is to avoid mosquito bites, treat the symptoms, and take anti-inflammatory drugs. The symptoms for Dengue vary depending on the severity. Mild symptoms include; Severe headache, Severe eye pain, Joint pain, Muscle or bone pain, Rash, Mild bleeding (nose or easy bruising). DHF symptoms include; bleeding from the mouth, gums, or nose, clammy skin, damage to lymph and blood vessels, internal bleeding, which can lead to black vomit and feces, or stools, lower number of platelets in blood, sensitive stomach, small blood spots under the skin, weak pulse. DSS symptoms include; intense stomach pain, disorientation, sudden hypertension, or a fast drop in blood pressure, heavy bleeding, regular vomiting, blood vessels leaking fluid. Dengue fever is known to have a fever that lasts around 2-7 days with the symptoms described previously.

The journey of Dengue Fever begins three to fifteen days after being bitten by the mosquito that carries dengue. One to five days in the infected will begin to feel a headache with a severe pain behind their eye, they will also begin to experience an acute fever. Five to seven days in the infected will begin to experience the severe symptoms, the fever will begin to decline and some warning signs may appear, “This marks the beginning of a 24 to 48-hour period when the smallest blood vessels (capillaries) become excessively permeable (“leaky”), allowing the fluid component to escape from the blood vessels into the peritoneum (causing ascites) and pleural cavity (leading to pleural effusions). This may lead to failure of the circulatory system and shock, and possibly death without prompt” (CDC 2012). The days after this will be the recovery period where the infected will begin to feel normal again. However, this is not the case for patients that begin to experience DHF. In DHF cases as the fever of DF begins to decline around 24 hours later the patient will begin to experience puncture bleeding and hemorrhagic manifestations. Plasma leakage is the most significant test to determine the severity of the DHF case. Signs of circulatory failure, flushed face, and restlessness follow around 24-36 hours later. In this critical time, the patient must be monitored closely to ensure they do not enter dengue shock. Although with the right care and medicine patients can still recover.

Dengue is a very old disease with traces of a dengue like illness that dates back to 922 AD in China. (Kumar 2010). Dengue became an epidemic due to the increase in trading and shipping. In 1818 the first epidemic of Dengue was recorded with around 50,000 cases documented. Dengue became a global concern in 1827, when dengue became a pandemic disease in the Atlantic-Gulf-region. During world war II dengue emerged as a pandemic in southeast Asia where it became a pandemic. It began reaching areas of south and central America. (Chakraborty 2008). The hemorrhagic dengue appeared in the 1950s in Southeast Asia. In recent times distribution of dengue has increased significantly. To this day 2.5 million people are at risk of being exposed to the dengue virus. Due to the urbanization in tropical developing countries, modern transportation, and lack of effective mosquito control in the last 25 years there has been a dramatic geographic expansion of dengue. Around 390 million infections occur per year. The CDC concluded that, “Dengue is endemic in at least 100 countries in Asia, the Pacific, the Americas, Africa, and the Caribbean.” (CDC 2012).

Dengue is transmitted from one person to another by two species of mosquitos the Aedes aegypti and the Aedes albopictus mosquitos. In rare cases dengue can be spread by organ transplants or blood transfusions from an infected victim to a healthy recipient. A mosquito becomes a carrier if it bites a victim during the first three days of the infected victim’s illness. It then takes 8 to 11 days to incubate the virus before the disease can be transmitted. After that the mosquito remains infected for life and can infect other individuals. Once mosquitos have the infected disease they can then pass that on to their larvae and from there mosquitos are born ready to bite and spread. (Nedjadi, 2015). Transmission rates have grown in Asia and Africa due to rapid urbanization in the tropics and growth in cities making it a perfect place for mosquitos. Also, due to the careless waste methods in these regions, trash collects rain water where the mosquitos reproduce. (Kumar 2010). Increased air travel from endemic regions to non-endemic regions is adding to increased transmission.

There is no specific cure or treatment for Dengue, there are only a few ways to vet the symptoms. Paracetamol can be used to help with the pain and fever. As soon as dengue is identified hydration is extremely important to ensure the symptoms are kept under control. The patient should be watched closely once the fever begins to decrease in case the patient goes into shock. (Gibbons 2002). The vaccine industry is facing any problems while trying to find a cure for this virus. It has been especially challenging because the virus has four stereotypes and it is hard to manufacture a vaccine to cover all four stereotypes. Another problem they are running into is that they do not have a full understanding of the immunopathology of the virus therefor they are having a hard time going through clinical trials with such little knowledge. They are making big steps though they have finally developed a prototype still going through trials but has made it through three so far. (Thomas 2015). Researchers are also using anti-bodies on animal models to test, the results of these animal trials may allow a new drug treatment for people with dengue. The Virology Journal concluded that, “Vaccines which are being developed using various approaches such as live attenuated viruses, inactivated viruses, subunit vaccines, DNA vaccines, and chimeric viruses using yellow fever vaccine and attenuated dengue viruses as backbones.” (Nedjadi, 2015). While scientists are working day and night to develop a vaccine they haven’t been able to develop one that can cure and prevent all four stereotypes.

There are a few ways Dengue can be prevented. They main solution is vector control, to limit the mosquito population limits the amount of infections. Vector can be achieved a number of ways environmentally, chemically, and biologically. Environmentally changes include regularly cleaning and draining flower pots, coolers, pipes, any areas that can collect water that allow mosquitos to reproduce. Chemically this can be achieved by insecticides but chemical efforts lead to environmental damage and can hurt other living organisms and habitats. (Kumar 2010). Biologically, companies like Oxitec are genetically engineering mosquitos to target vector mosquitos that carry not only dengue but Malaria, Yellow Fever, and Zika. They are doing this by genetically creating male mosquitos to sterilize and kill the female vectors while keeping the mosquitos that do not carry diseases. (Oxitec 2016). Prevention can also be done by wearing clothing that does not expose much skin making it difficult to be bitten by a potential vector. Even just spraying some bug spray or mosquito repellent can help keep you from getting dengue. For households in tropical regions it is important to put wired mesh around the doors and windows making it almost impossible for mosquitos to make it inside. The only problem with a few of these prevention solutions is they require action and personal will. Not everyone has access to wired mesh or even the clothing needed to cover their skin.