What is the treatment for dengue fever

Dengue fever

Brief overview

  • What is dengue fever? A viral infection transmitted by the Aedes mosquito.
  • Occurrence: mainly in tropical and subtropical countries, but also (occasionally) in Europe.
  • Symptoms: sometimes no symptoms, otherwise typically flu-like symptoms (such as fever, chills, headache and body aches, muscle pain); in the event of complications Blood clotting disorders, vomiting, drop in blood pressure, restlessness, drowsiness
  • Treatment: symptomatic with hydration and pain relievers and febrile drugs; in-patient intensive care in the event of complications
  • Forecast: mostly benign course; increased risk of complications in children and secondary infections
  • Prevention: Avoiding mosquito bites (long clothes, mosquito net, mosquito repellent, etc.)

Dengue fever: routes of infection and occurrence

Dengue fever is caused by the dengue virus, which comes in four different variants (serotypes): DENV 1-4. All of them are from the Aedes mosquito transmitted - most often by the yellow fever or tiger mosquito (Aedes aegypti or Stegomyia aegytpi), sometimes also by the Asian tiger mosquito (Aedes or Stegomyia albopictus).

These mosquitoes are mainly found in urban areas or generally in human-populated areas. They prefer to lay their eggs near water (bottles, rain barrels, buckets, etc.). If females are infected, they can transmit the virus directly to the brood. It is also the female mosquitoes that pass the disease on to humans.

Can people infect each other with dengue?

People usually become infected with dengue viruses through a bite from Aedes mosquitoes. The stinging animals can also absorb the infected blood of sick people and transmit it to other people.

A direct dengue transmission from person to person - i.e. without the presence of Aedes mosquitoes - does not usually take place.

In contrast to flu viruses, for example, dengue viruses do not occur in saliva according to current knowledge. Dengue fever cannot be transmitted through sneezing, coughing or kissing. However, there are isolated cases in which researchers assume that individuals find out about unprotected sex have infected.

The European Center for Disease Prevention and Control (ECDC) therefore advises that patients with or suspected of having dengue fever should not practice or practice safer sex during the period of illness. However, the experts also emphasize that further studies are necessary for a more precise statement.

So far, researchers have been able to detect dengue virus RNA in semen, vaginal secretions and urine. To what extent an infection can occur through this remains unclear (it is also conceivable that the infection is caused by small injuries that occurred during sexual intercourse and that infected blood is transferred). A positive test does not necessarily mean that the person affected is contagious, as it only detects the genetic make-up of the dengue virus.

There are also isolated reports on Pregnant womenwho passed the virus on to their unborn child through the blood. Doctors call this transmission path vertical transmission. A transmission of the virus through breast milk has so far been assumed in a single case. In addition, infection with the dengue virus is possible through infected blood (transfusions, needlestick injuries).

Although very rarely reported, the direct transmission of the dengue virus from people to one another does not play a relevant role in the spread of dengue fever, according to experts. The transmission via Aedes mosquitoes is decisive.

Occurrence of dengue fever

Dengue fever is the most common and fastest spreading mosquito-borne infectious disease worldwide. Southeast Asia, South and Central America, parts of the Pacific such as New Caledonia and Hawaii as well as Africa and Australia are particularly affected.

Due to global warming, the Asian tiger mosquito is meanwhile also widespread in southern Europe and is expanding its settlement area. In recent years, there have been isolated local dengue infections in Europe, such as in Madeira, Croatia, France or Spain. Experts fear that the mosquito will also increasingly spread to continental Europe.

The Aedes mosquito is not at home in Germany so far. German dengue fever patients were infected in tropical and subtropical countries. Since Germans like to travel more and more, the number of dengue fever cases introduced has risen sharply in recent years. Around 600 cases were reported in Germany in 2018.

According to reporting data from the Infection Protection Act (IfSG), the most common countries of infection in 2018 were:

  • Thailand: 38 percent
  • India: 8 percent
  • Maldives: 5 percent
  • Indonesia: 5 percent
  • Cuba: 4 percent
  • Cambodia: 4 percent
  • Sri Lanka: 4 percent
  • Vietnam: 3 percent
  • Mexico: 2 percent
  • Tanzania: 2 percent
  • Others: 25 percent

Dengue fever is one of the notifiable diseases in Germany. This means that the attending physician must report every case to the health department. This measure should help to identify larger outbreaks as quickly as possible and to be able to take countermeasures.

Dengue fever: diseases are on the rise

Dengue fever has spread over the past few decades. Over the past 50 years, the number of people infected has increased thirty-fold. Experts estimate that between 284 and 528 million people worldwide develop the dengue virus every year.

Don't give the mosquitoes a chance!

  • This is the best way to protect yourself from mosquitoes!

    Not only people are happy about the increased temperatures, mosquitoes also appreciate them. Fortunately, nobody is defenseless against the bloodsuckers. We have the best tips for you on how to protect yourself from the bites and get a bargain from the nasty itch.
  • Making mosquito brood homeless

    Even tiny puddles are enough for mosquitoes to reproduce. Remove the breeding opportunities in your garden and on the balcony. This means that there should be no water in the pots, the rain barrel should be covered and the rain gutter so clean that no mini-puddles form there.
  • Barring windows and doors?

    You don't have to be that blatant - mosquito screens on windows and doors do the same. So you don't have to go without fresh air on hot nights and the mosquitoes still stay outside.
  • Sleep without troublemakers

    If you have mosquitoes buzzing around your head at night, you will not only be bitten the next morning but also have no sleep. The simplest solution for a good night's sleep despite the bloodsuckers: hang a mosquito net over the bed. In the tropics, nets are even a must to protect against malaria and other mosquito-borne diseases.
  • Invisible to mosquitoes

    If you are outdoors, you should spray yourself with mosquito repellent. This "confuses" the mosquito's senses - they can no longer locate you correctly at a short distance. The most effective active ingredient is DEET, but it has recently fallen into disrepute. Alternatively, there is also a substance called Icaridin.
  • Plumes of smoke against mosquitoes

    Candles with essential oils show practically no effect against mosquitoes. Incense coils, on the other hand, do. However, they should only be burned outdoors.
  • Use heat to drive out itching

    With the bite, the mosquito's saliva gets into the skin - this contains coagulation factors that later trigger the itching. There are devices that cause a small heat shock locally and are supposed to render these enzymes harmless. However, this only helps immediately after the bite and only the upper layers of the skin are reached.
  • Stitch, freshly chilled

    To reduce the swelling and any tension pain, it helps to cool the sting. Cold compresses, cooling pads or ice cubes are suitable for this.
  • Ointments and gels for mosquito bites

    There are various products on the market for creaming that inhibit the body's own messenger substance histamine. This prevents the immune system from becoming as active. The swelling should go back faster and the itching should decrease.
  • Do not scratch!

    Important: do not scratch your mosquito bites! While this provides satisfaction in the short term, it only makes the sting worse in the long run. Because you heat up the immune reaction vigorously and can also work bacteria into the wound. For a "good" feeling, it is better to scratch right next to the sting - this is supposed to be the way to outsmart the brain.
  • Of
    Medical editor and biologist

Dengue fever: symptoms

The time between the bite of the Aedes mosquito and the appearance of the first symptoms (incubation period) is three to 14 days. Most of the time, the infection breaks out between the 4th and 7th day.

The symptoms of dengue fever are often very unspecific and are similar to those of ordinary flu: Typically, the patient has high fever (up to 40 degrees Celsius), chills, Head-, Joint and limb pain. Because of the severe muscle pain, dengue fever is also "Bone Breaker Fever". The fever often has two peaks (biphasic). Together with the second fever, a rubella-like, itchy rash occur all over the body. Other possible accompanying symptoms in dengue fever are, for example Exhaustion, nausea,Vomit as swollen lymph nodes.

Many infected people also show no symptoms at all (especially children).

Complications in dengue fever

In the majority of patients, dengue fever heals without any further consequences. In some cases, however, there are complications: Doctors differentiate between two serious disease courses that can also be life-threatening. They occur primarily in children and adolescents under the age of 15 and generally in patients who have already suffered from dengue:

Dengue Hemorrhagic Fever (DHF): In the case of hemorrhagic dengue fever, an acute fever outbreak is followed by symptoms that are caused by a sharp drop in blood platelets (thrombocytopenia) - various bleeding types such as pinhead-sized bleeding into the skin or mucous membranes (petechiae), nose and gum bleeding as well as gastrointestinal bleeding occur ( vomiting blood and bloody stools).

Dengue Shock Syndrome (DSS): If the blood pressure derails due to the illness, the heart can no longer pump enough blood around the body. As a result, the heart rate rises sharply. Nevertheless, vital organs such as the brain and kidneys are no longer adequately supplied.

Warning signs of such complications are:

  • sudden abdominal pain
  • repeated vomiting
  • sudden drop in body temperature below 36 ° C
  • sudden bleeding
  • Confusion, agitation, or lightheadedness
  • sudden drop in blood pressure
  • fast pulse

Both complications are potentially life threatening and require hospital treatment. The tricky thing: They usually only appear when the patient is already feeling better again, often between the third and seventh day of the illness. For this reason, one speaks of the in this context critical phase, because now the course of the disease is revealed and the doctor has to decide whether (drastic) countermeasures need to be taken.

Dengue fever: treatment

There is no causal therapy for this infection. This means that the doctor can only alleviate the symptoms, but not fight the virus itself.

Dengue fever treatment does not differ significantly from that of the flu in the fever phase without complications: one thing is important adequate hydration. You can also take action against the high fever and pain pain reliever and antipyretic drug like taking acetaminophen. Pain relievers and fever medicines, which impair blood clotting and thus increase the bleeding tendency, are not suitable. These include above all acetylsalicylic acid (ASA), but also ibuprofen.

As long as there are no complications, the patient does not necessarily have to go to the hospital. However, as soon as signs of bleeding appear or a shock threatens, inpatient treatment (possibly in the intensive care unit) is unavoidable. The vital parameters (heart and respiratory rate, blood pressure, etc.) can be precisely monitored there. In addition, the patients are given infusions or blood reserves as required.

The risk of complications is particularly high when the fever subsides. Any deterioration in health should then be reported to the doctor immediately.

Dengue fever: prevention

In October 2018, the European Medicines Agency (EMA) approved a vaccine against dengue for the European market. For most EU citizens, however, this authorization does not matter. It is restricted to people who are nine to 45 years old, who live in an endemic area (e.g. La Réunion, Guadeloupe or French Polynesia) and who have ever suffered from dengue fever. The dengue vaccine is also not permitted as a travel vaccine.

Research has shown that people who have not had dengue fever and have been vaccinated have a slightly increased risk of developing serious dengue. That is why only people who have survived the infection receive the dengue vaccination.

According to the Robert Koch Institute, scientists are researching several other vaccines against dengue fever, some of them in clinical test phases. Until then, some measures will help to prevent dengue fever in the first place. The most important thing is to protect yourself from mosquito bites when traveling to risk countries (Exposure prophylaxis). The following protective measures are recommended:

  • wear long trousers and long sleeves
  • Apply repellents (mosquito sprays) to skin and clothing
  • Mosquito nets with a mesh size of no more than 1.2 mm - this corresponds to approx. 200 MESH (meshes / inch2) - stretch over the bed
  • Install fly screens on windows and doors (impregnated with insecticides)

If you are planning a trip to a dengue fever area, you should inform yourself carefully about the risks and protective measures before you travel. Travel doctors and tropical institutes offer appropriate advice.

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Dengue fever: examinations and diagnosis

The main symptoms of dengue fever are indistinguishable from those of normal flu in the early stages. However, a specialist doctor such as a tropical doctor can often suspect an infection with "dengue fever" based on the symptoms described and the information that the person concerned was in a risk country. The doctor collects such information from the Initial meeting with the patient (anamnesis).

That is also important physical examination. It includes:

  • Temperature, pulse and blood pressure measurement
  • Listening to the sounds of your heart and lungs
  • Palpation of the superficial lymph nodes
  • Examination of the throat and mucous membranes

The suspicion of dengue fever lets through Blood tests Confirm: A blood sample from the patient is examined for dengue viruses and specific antibodies against the pathogen. Rapid tests for the detection of specific antibodies are also available.

In addition, the doctor pays attention to signs of a tendency to bleed, for example in the form of bleeding gums, nosebleeds or small skin hemorrhages (petechiae). In this context, the so-called Tourniquet test valuable pointers. It can be used to check the stability of the finest blood vessels (capillaries): To do this, a blood pressure cuff is placed on the patient's upper arm and inflated to a value between systolic and diastolic blood pressure. After about ten minutes, the cuff is removed and the doctor will check to see if there are any small hemorrhages (petechiae) on your forearm.

Dengue fever: disease course and prognosis

Dengue fever is usually uneventful. Most patients recover within a few days. However, the exhaustion can persist for a few more weeks.

There is an increased risk of complications in dengue fever in patients who do not drink enough or who are younger than 15 years. A second infection with dengue viruses is also dangerous:

After a dengue fever infection one is immune to the respective type of dengue virus for life. But you can become infected with one of the other three virus types and get sick again. This second infection is often more serious (for example as dengue hemorrhagic fever). Experts suspect that an overreaction of the immune system is responsible for the more severe course of the disease. People who have already suffered from dengue fever must therefore be particularly careful when traveling to the tropics again.

Risk of death

In the case of dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), timely intensive medical treatment is very important. The mortality (lethality) with DHF is between six and 30 percent.The DSS is even more dangerous: Without adequate treatment, 40 to 50 percent of patients die from this difficult form of Dengue fever. With timely therapy, however, the mortality drops to one percent or less.

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