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When you travel to the tropics, any doctor will tell you about the prevention of malaria. However, you won’t always learn about dengue, which is the most common insect-borne viral infection in the world.
Ania and Robert decided to professionally prepare for their Asian journey. They planned a tour of Thailand, Cambodia and Vietnam. Before leaving, they went to the Sanepid station to vaccinate themselves against the diseases that threatened them in these areas. In the waiting room, all the posters warned against malaria. The doctor qualifying for vaccinations also informed them about anti-malaria prophylaxis. It consists in taking appropriate medications during the stay and a few days after returning. They spent over a thousand zlotys on vaccinations and purchase of antimalarial drugs. Equipped with the knowledge gained from the doctor and anti-malaria pills, they set off into the world.
Malaria prophylaxis
In Cambodia, a local driver told them that many tourists and locals have dengue. – Why did no one mention denga in Sanepid? – they wondered. They were to avoid malar mosquitoes, especially after dark and in rural areas. Meanwhile, the dengue virus is transmitted by insects that are active mainly during the day and well adapted to urban conditions, where they use small freshwater reservoirs as breeding places, e.g. buckets or cans filled with rainwater. They did not know at all what the symptoms of dengue were and what to do if they appeared.
Meanwhile, dengue fever is a very common viral infection transmitted by insects and is the most commonly diagnosed disease among tourists who come to tropical medicine centers due to fever after returning from tropical areas. The exception is sub-Saharan Africa, where malaria patients still predominate.
Dr. Andrzej Kotłowski, MD, head of the Department of Tropical Medicine and Epidemiology at the Medical University of Gdańsk, explains that it is best to consult a doctor specializing in travel medicine before leaving. – There are already 150 Certified Travel Medicine Centers in the country. A doctor employed in such a center will surely tell us about the dengue – he explains. He also adds that it is not surprising that malaria prevention is more publicized. A pharmaceutical company that produces a drug that is not cheap after all, cares about educating travelers, as it thus increases the sale of its product. And since there is no cure or vaccine for dengue fever, no one is organizing such an intensive educational campaign.
The spread of dengue
Until the mid-twentieth century, the incidence of dengue was limited to areas of the tropical zone. – Sea transport of goods and air traffic have contributed to the spread of this disease – explains Dr. Andrzej Kotłowski. Dengue cases are reported in the USA in Florida and in Europe in the Mediterranean basin. Annually, the dengue virus kills more than 20. people in the world. Nobody knows exactly how much they get sick, because not every infection is diagnosed and reported.
Governments of many countries are fighting dengue. Recently, in Brazil, mass production of genetically modified mosquitoes to tackle the disease began. Male mutant mosquitoes will be released twice as many as the non-GM mosquito population. They will attract female mosquitoes to beget offspring that will die before adulthood. The local health ministry has planned to release 4 million mosquitoes per week.
Dengue symptoms
Dengue symptoms usually appear 3–14 days after an infected mosquito bites. – These are flu-like symptoms, mainly characterized by weakness and aches and pains in the joints. Unfortunately, the symptoms are not always the same. There may also be fever, headache, conjunctivitis or pharyngitis, and gastrointestinal discomfort. Some people also develop a rash – says Dr. Kotłowski. Some patients develop a hemorrhagic form or shock. As a result of blood coagulation disorders, ecchymoses appear on the skin and bleeding from the mucous membranes of the nose, mouth or genital tract and gastrointestinal tract. These disorders are life-threatening and usually appear after a few days of illness.
In Thailand, Ania and Tomek traveled by air-conditioned bus. The driver did not spare air conditioning. On the second day, they both felt a bit cold. Tomek had a cold and Ania was weak and her bones broke a little. The first thing that occurred to them was to take aspirin.
First aid in denga
Meanwhile, if flu-like ailments are caused by contracting dengue, taking aspirin is a big mistake. – In the case of dengue, avoid taking medications that affect the clotting system, such as acetylsalicylic acid – aspirin, ibuprofen and others, as they may worsen bleeding problems. However, you can use paracetamol – says Dr. Kotłowski.
Ania and Tomek took only the aspirin, because no one told them about denga. So they only decided to have hot tea. They did not go to the doctor because the next day they felt better.
Dr. Kotłowski advises that in the event that flu problems arise during our trip, lie down for a few days and rest. If your fever worsens or you develop a rash, see your doctor. If bleeding occurs, you should go to a hospital, preferably in a big city, and if you can go to the capital. Treatment consists in eliminating symptoms, i.e. mainly rehydrating the body with oral preparations or drips, combating fever and pain, and correcting blood coagulation disorders. – In many Asian and South American countries, the level of medical services provision differs from that in Europe. That’s why the Germans say that the best hospital in the tropics is Lufthansa, which will take you to Europe. Unfortunately, it is not always time to come back. If the disease develops dynamically, you need to seek help on the spot – says Dr. Kotłowski.
Study after returning from tropical countries
If we have had a fever or other ailments, we should consult a travel medicine specialist during or after our return. Especially since it is suspected that a previous dengue infection increases the risk of a severe course of the disease and its bleeding complications during a subsequent infection.
Ania and Tomek, after their return, reported to such a center. They told the doctor that they feared they had contracted dengue. Based on the interview, the doctor decided that it was possible. He ordered them to test for anti-dengue antibodies in the blood. It turned out that only Ewa suffered from dengue. The doctor suggested that for the next few years she should not travel to areas where this disease occurs. Ania and Tomek are not going to stop traveling around the world. They plan to visit dengue-free areas in the coming years. The Faroe Islands, Iceland and Canada are planned. But in a few years they would like to visit Asia again. Dr. Kotłowski emphasizes that there is no vaccine or cure for dengue fever. The only prevention is avoiding mosquitoes. – You must use mosquito repellent preparations, and those containing DET. They can be used to soak clothes and lubricate the skin. If there is an increase in dengue incidence in your region, it is better not to go there. And while dengue is a growing problem, let’s not forget about malaria, which is killing many more people. While anti-malaria drugs aren’t cheap, don’t spare your money. It also happens that the first attack of malaria may turn out to be fatal, the doctor warns.
Text: Halina Pilonis