Dengue is an infectious disease caused by four serotypes of viruses – Den-1, Den-2, Den-3 and Den-4 – belonging to the Flavivirus genus (the same genus to which the viruses responsible for yellow fever, a West Nile, Japanese encephalitis and tick-borne encephalitis).
How it is transmitted
The infection is transmitted through the bite of mosquitoes, mainly of the species Aedes aegypti and to a lesser extent by Aedes albopictus (the so-called tiger mosquito), which pass the virus into a healthy individual after biting an infected one (these same mosquitoes can also transmit other viruses: the Zika virus and the Chikungunya virus). Until recently, dengue was widespread mainly in the tropical and subtropical regions of Africa, Southeast Asia, China, India, the Middle East, Latin and Central America, Australia and several areas of the Pacific. However, in recent decades, climate change and the increase in the movement of people and goods have also led to cases being recorded in some European countries, including Italy, France and Spain.
How it manifests itself
Dengue symptoms typically appear 4-10 days after being bitten by an infected mosquito. High fever, headache, pain in the eyes but also in the muscles and joints usually appear, symptoms that can often be mistaken for those of a normal flu. Sometimes you may experience a rash, nausea, vomiting, and mild bleeding (such as nose or gum bleeding). In more severe cases, dengue can progress to a more dangerous hemorrhagic form that requires immediate treatment. This event can occur, for example, if the person who is bitten by an infected mosquito has already been infected previously.
How to treat it
There is no specific treatment for dengue, but in most cases people recover within two weeks. To alleviate the symptoms, however, you can resort to supportive care such as maintaining hydration and taking mild analgesics to relieve the pain.
How to prevent it
The main form of prevention is to avoid mosquito bites in risk areas, using mosquito nets, insect repellents and clothing that covers the legs and arms as well as the rest of the body. The control of mosquito populations can take place on an individual scale – avoiding stagnation of water on terraces and gardens, which favors the reproduction of mosquitoes – and on a municipal scale, with disinfestation measures.
In the autumn of 2023, a new vaccine was authorized in Italy that can be administered to all subjects over 4 years of age (but is not recommended for pregnant or breastfeeding women). It is a live attenuated tetravalent vaccine against the disease caused by any of the four serotypes of the virus and can be administered both to those who have already been exposed to the infection previously and to those who have never contracted it. The vaccine is intended for those who have to travel to risk areas, for tourism or work, and involves two subcutaneous doses three months apart. Its side effects are light and transient: some pain and redness at the injection site, some fever, headache or muscle aches.