Is dengue fever transmissible

What is dengue fever?

In Germany, the disease occurs primarily in travelers who were mainly traveling in Southeast Asia or South or Central America. Typical countries of infection are, for example, Thailand, India, Indonesia or Brazil. In addition, the pathogens of dengue fever could now, albeit much less often, get into the human body via mosquito bites in southern Europe. The infection was detected in travelers in southern France and Croatia for the first time in 2010.

Currently, experts estimate that around 10 out of 100,000 tourists get dengue fever. The number of diseases is apparently increasing steadily. In this country, almost 300 people fell ill in 2009, while there were more than 380 in 2010 and 1,029 cases were reported in 2016. Overall, dengue fever is the most common viral disease that travelers bring with them from the tropics.

How can you get dengue fever?

So-called dengue viruses (DENV) cause dengue fever, of which four different types (subgroups or serotypes) are known. The viruses can get into the human body through the bites of certain mosquitoes. These mosquitoes are found in both urban and rural areas. They are mainly active during the day and at dusk. Even the smallest accumulations of water are sufficient for them as a breeding ground, with high temperatures leading to strong and rapid reproduction.

Children and adolescents in so-called endemic areas in particular - these are areas that are home to dengue fever - often become seriously ill when they become infected again with another type of dengue virus.

Europeans are usually infected when they are on vacation in the corresponding areas. The blood-sucking mosquitoes harbor the pathogens that enter the human body when it bites and multiply there. The disease can break out after three to 14 days, usually after four to seven days.

Various forms of the course are possible, ranging from mild symptoms to the classic course to life-threatening clinical pictures.

What are the symptoms of dengue fever?

Classic dengue fever can begin with flu-like symptoms and a sudden rise in fever of up to 40 degrees Celsius. The fever is often accompanied by chills and severe exhaustion as well as severe headache and body aches, and conjunctivitis is also possible. Joint and muscle pain can also occur. It is not uncommon for the fever to last for two to four days, and a slow pulse can sometimes be felt. In addition, skin rashes, spleen and lymph node swellings are possible symptoms.

After the fever has gone down, the temperature can rise again after a day or two, then often a large skin rash occurs, which may affect the entire body, but not the face. Small hemorrhages in the skin and mucous membrane are also possible. It is not uncommon for the subsequent recovery phase to take a long time and can take several weeks.

With a mild course of dengue fever, similar symptoms occur, only they are significantly weaker. In total, the disease does not last longer than three days.

How is the suspected diagnosis secured?

A tropical doctor can usually make the diagnosis based on the typical symptoms and the course of the disease. Travelers returning from endemic areas should report to their doctor about their stay abroad. Blood tests often confirm the diagnosis by detecting the pathogen as well as antibodies targeted against dengue viruses. From the eighth day of illness, antibodies against the dengue virus can be detected in the blood. If this is the case, the local health department must find out, because dengue fever is a reportable disease. The doctors take care of the report.

What complications are possible?

Sometimes there are complications. The so-called hemorrhagic dengue fever (DHF) or dengue shock syndrome (DSS) mainly occurs in children who are under 15 years of age and have already suffered from dengue fever. A different type of dengue virus is responsible for the disease.

Possible symptoms of the life-threatening forms of hemorrhagic dengue fever and dengue shock syndrome are rapid rise in fever, vomiting, shortness of breath and headache. This can lead to massive coagulation disorders with heavy bleeding such as bleeding in the skin and mucous membranes, nosebleeds, gastrointestinal tract bleeding with vomiting of blood and so on. It is not uncommon for these complications to be accompanied by a drop in blood pressure and circulatory collapse, which can occur two to six days after the onset of the disease.

Overall, between six and 30 percent of those affected by dengue hemorrhagic fever and dengue shock syndrome die. Small children are particularly likely to die.

How is the disease treated?

Dengue fever can only be treated symptomatically, that is, the symptoms are combated. There is no therapy aimed specifically against the dengue virus. In this way, the doctor can prescribe pain reliever and antipyretic medication. However, acetylsalicylic acid is unsuitable because it can increase the bleeding tendency.

Often the sick tend to drink too little. Sweating at the same time can quickly lead to a lack of fluids. It is therefore advisable to drink a lot. Medical treatment in the hospital may be necessary if the course of the disease is complicated. Rapid intensive medical care is necessary for hemorrhagic dengue fever and dengue shock syndrome.

What protective measures are there?

There is (so far) no effective vaccination. But it is being tested. The only possible protection is currently to avoid mosquito bites.

The following rules of conduct should be observed:

  • Wear long pants and long-sleeved clothing (the mosquitoes can often bite through clothing, however)
  • Install mosquito screens on windows and air conditioning systems or keep windows closed
  • Spray an insecticide half an hour before bedtime
  • Light so-called mosquito coils
  • Switch on air conditioning
  • Sleep under a mosquito net
  • Rub exposed parts of the body with a recommended mosquito repellent

With these measures you also protect yourself against other diseases, for example against malaria.

Am I protected after an illness?

Unfortunately, a single illness does not protect against further infection. Because there are four different viruses known that can cause dengue fever. According to the current state of science, a person who stays increasingly in areas where dengue fever occurs can fall ill up to four times according to the current state of science. Initial illnesses are usually benign and heal without complications. With secondary infections, however, a severe course is possible.