Once upon a time, only those who traveled to the tropics were at risk of contracting dengue. Today the danger can also lurk in the Po Valley or on the Roman coast.
«The main vector of the disease is the mosquito Aedes aegyptiwhich is not circulating in Italy for now, because it has difficulty surviving in our latitudes – he clarifies Adriano Casulli, researcher at the Department of Infectious Diseases of the Higher Institute of Health (ISS) —. However, mosquitoes can also transmit the dengue virus Aedes albopictusknown as “Tiger mosquito“, present for over 30 years in our country and now widespread from the Alps to Sicily.” L’Aedes aegypti is triggering an epidemic in South America, which is why Italian health authorities have raised guard levels in ports and airports.
Dengue symptoms
Dengue, which manifests itself with even very high fever, severe headaches, nausea, skin irritation and muscle-joint pain, is one of the so-called “neglected tropical diseases”. “A group of 21 pathologiesincluding snakebite poisoning, predominantly of an infectious nature and typical of tropical and subtropical areas of the world, which despite constituting a preventable global health problem are still neglected by scientific research, little known by health workers and underdiagnosed – he explains Federico Gobbi, director of the infectious and tropical diseases department of the Irccs Don Calabria of Negrar —. In Italy we have observed the presence of at least 12 of these pathologies.”
The diseases
They are caused by viruses, bacteria, fungi and parasites (helminths and protozoa). «They are endemic to us, in the sense that they circulate and are transmitted here too:
- dengue, which in 2023 recorded 82 indigenous cases in addition to the 280 imported – reports Gobbi -;
- chikungunya, again carried by the tiger mosquito, which causes fever and joint pain, has generated two outbreaks, in 2007 and 2017, and there is a risk that it will return;
- leishmaniasis, transmitted by sandflies, which affects the skin, causing lesions and ulcers, or the visceral organs, with fever and enlargement of the liver and spleen;
- scabies, due to a mite that triggers intense itching and skin signs;
- cystic echinococcosis, which results from the ingestion of echinococcus larva eggs, a parasite present in foods contaminated by feces of infected dogs, responsible for large cysts in the liver, lungs or brain;
- L’opisthorchiasistransmitted by a worm through the ingestion of raw fish (le other pathologies found, such as Chagas disease and schistosomiasis, concern imported cases)”.
More and more insects
The ISS infectious diseases department is a WHO collaborating center for the identification and control of echinococcosis: «Between 1997 and 2021 we detected more than 15 thousand cases and 25 thousand hospitalizations and for the first time, in 2024, it is a case of alveolar echinococcosis has been documented, which if not treated is fatal” reports Casulli.
The globalization of travel and goods, migrations and global warming have favored the circulation of pathogens outside the original endemic areas. «Climate changes increase the density of mosquitoes and their ability to acquire and transmit viruses. At higher temperatures, between 28-30 degrees, mosquitoes reproduce faster and bite more frequently because the “blood meals” to produce the eggs are closer together. Furthermore, with milder springs and autumns, their period of activity is lengthened beyond the summer season” he points out Claudio De Liberatoentomologist of the Experimental Zooprophylactic Institute of Lazio and Tuscany.
Suspect fever in spring-summer
A study published in 2019 estimated just over 4 thousand cases of neglected tropical diseases in our country between 2011 and 2017, of which 69% occurred in immigrant people. «The most common mistake made by doctors is not to consider vector-borne diseases among the causes of fever in late spring, during summer and early autumn. That of citizens, not to resort to infectious and tropical diseases centers in the event of the onset of fever or other symptoms upon returning from a trip” underlines Gobbi. «Before leaving for an international trip it is a good idea to find out from the ASL travel medicine center about vaccinations to be done and precautions to be taken».
Be careful when swimming in fresh water
The World Health Organization has set a road map to reduce infections, disabilities and deaths caused by neglected tropical diseases by 2030. In Italy between 2011 and 2017 approximately 4 thousand cases were diagnosed. «The most frequent pathologies – says infectious disease specialist Federico Gobbi, one of the authors of the research – are:
- schistosomiasis, due to bathing in fresh water contaminated by larvae capable of penetrating the skin which in chronic form can cause disorders of the liver, intestine, bladder and genitals;
- strongyloidosiswhich is acquired from contact with soil infested with another type of worm, which in immunocompromised individuals can give rise to hyperinfection of various organs and be potentially fatal;
- chagas diseasetransmitted by a bedbug widespread in Latin America but also from an infected mother to a newborn, which can cause cardiac and gastrointestinal complications, up to and including death in the most serious cases.”
How to protect yourself from mosquito bites
You don’t have to defend yourself only from the tiger mosquito. But also by the common mosquito (the species culex pipiens), active especially in the evening and at night, the main means of transmission of the West Nile virus, which last year in Italy was found in 332 people (in 20% of cases the symptoms are mild; more serious in elderly and debilitated people: high fever, headache, tremors, disorientation, visual disturbances).
How to protect yourself from mosquito bites, then? «In the early morning, late afternoon and evening, when they are more aggressive, if you are outdoors it is important to apply repellents on the skin based on Deet or icaridin, with a concentration of at least 20%. For newborns and pregnant women, an anti-mosquito product containing citrodiol, a natural active ingredient, is recommended – says infectious disease specialist Federico Gobbi -. To keep insects away from the house, mosquito nets on windows and children’s beds, mosquito nets and plates are useful.”
April 22, 2024
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