Dengue fever is one of the tropical infectious diseases and causes 50-100 million cases of disease worldwide every year, and the trend is rising. Certain types of mosquitoes transmit the pathogen, the dengue virus, to humans. Depending on e.g. age and state of health, the symptoms of the disease can vary greatly.
The spectrum ranges from mild, flu-like courses to serious, highly feverish episodes involving several organ systems. The most feared complication is the “dengue shock syndrome” (DSS), which is fatal in about 30% of cases. Unfortunately, there is currently neither a protective vaccination nor a causal therapy against dengue fever. Prophylactically, therefore, the protection against insect bites is primarily in the foreground. Patients can only be treated symptomatically, e.g. by giving them fluids and protein.
Transmission
The disease is transmitted by so-called “vectors”: In this process, an organism transports the pathogen from host to host. The most important vectors of the dengue virus are the females of the Egyptian and Asian tiger mosquito (lat. : Stegomyia aegypti and Stegomyia albopticus).
Due to their striking black and white patterned pattern it is usually easy to recognize! With one bite they can easily carry the virus into the human bloodstream. Conversely, non-infected mosquitoes can pick up the pathogen from a sick person.
Since the day-active insects multiply in standing water, eradication is extremely difficult. Even small puddles or water-filled containers (e.g. bottles) are sufficient. The rate of spread is particularly high in densely populated residential areas.
In contrast to other tropical infectious diseases, such as Ebola, the human-to-human transmission of dengue fever is an absolute rarity! Isolation of the affected patients is therefore not necessary. Find out by which symptoms you can recognize a bite of the Asian tiger mosquito.
Distribution
Dengue is found in more than 100 countries in subtropical and tropical Asia, Australia, Central and South America, Oceania, Africa and the Caribbean. However, due to the increasing spread of the tiger mosquito, the disease is expected to spread to Europe in the future. There was already a major outbreak in 2012 on the Portuguese island of Madeira.
Cases have also been reported in southern France and Croatia. Due to the increasing long-distance tourism, the number of “imported” dengue cases is also growing: While 60 cases were reported in Germany in 2001, there were already 387 cases in October 2010. This particularly affected people returning from India and Southeast Asia (Thailand, Vietnam, Philippines, Malaysia and Indonesia).
Symptoms
Basically, one can distinguish between three forms of the disease: Flu-like dengue fever (DF), severe dengue haemorrhagic fever (DHS) and dangerous dengue shock syndrome (DSS). Age, nutritional status, health condition, gender and probably also genetic predisposition of the patient also seem to play an important role in the severity of the disease. If those affected also suffer from a secondary infection, i.e. if they have already contracted the virus repeatedly, one of the two severe forms of dengue fever (DHS and DSS) is all the more likely.
Small children often suffer from a high fever lasting 1-5 days at the beginning. It is only in older children and adults that the typical bipolar fever can often be observed: After an initial, short-lasting fever with sudden normalisation, a second fever increase follows, which usually lasts longer. Many affected persons complain of headaches, especially in the forehead and eye area, accompanied by nausea and abdominal pain.
In the vernacular dengue fever is often also called “bone-breaking fever”, as sufferers suffer from extremely painful back and limb pain. Sometimes a nodular, patchy rash can be observed. In the first few weeks of the disease, under certain circumstances there may be swelling of the lymph nodes throughout the body, as well as discomfort (lat.
: dysesthesia). More severe courses lead to a coagulation disorder, so that nose, skin and mucous membrane bleeding occurs. If the bleeding is severe, a lack of volume in the blood vessels can lead to a dangerous shock.
In this case we speak of life-threatening dengue shock syndrome (DSS). The preliminary stage, dengue haemorrhagic fever (DHF), however, occurs when the following 4 criteria are met:
