The holiday season is coming and many people look for their place of recreation and rest on the outside. When someone says they will visit a place with a tropical climate, the danger of certain diseases and the need for vaccines and other preventive measures to prevent contagion come to mind. And it is natural that like it is. What is often overlooked is that the risk of contracting these diseases is not only on the other side of the borders: the mosquitoes that spread them are also within our country.
These mosquitoes are not typical of these regions, but for different reasons they have arrived and even acclimatized. The most paradigmatic case may be that of the tiger mosquito. Originally from Southeast Asia, this animal - included in the list of 100 of the most harmful invasive alien species in the world, prepared by the International Union for the Conservation of Nature - has been detected in numerous Spanish municipalities and with such presence on the coasts Spaniards who are already considered settled there.
The tiger mosquito is a kind of "brother cousin" of the famous Aedes aegypti - also known as the yellow fever mosquito - and can fulfill its same functions. Basically, it becomes infected if it bites a person carrying any of these diseases. If it then bites a healthy person, it will spread it.
In addition, Aedes aegypti itself was detected in December 2017 in Fuerteventura. The Ministry of Health of the Canarian Government stressed that it was a "timely detection", and that "the mere presence of the mosquito does not mean that disease transmission is occurring", since these "are not present in the Canary Islands, except for sporadic imported cases ".
Although experts did not see a health risk on that occasion, the discovery of specimens of that species in Spain after 78 years (the previous detection had occurred in 1939 in Barcelona) is an element that requires further care and precautions. But what are the diseases that these mosquitoes can transmit? The most important are listed below.
It is a viral disease native to Africa and widespread in many countries of America and Asia. Symptoms may include fever, skin rash, joint pain and conjunctivitis. Its vector - that is, the organism that transmits it - are the mosquitoes of the genus Aedes. Until the end of last year, 325 confirmed cases had been registered in Spain, although only two of them had originated in our country - both sexually infected - and four had been congenital, by transmission from mother to fetus.
In any case, Zika in Spain is considered a real danger, especially in the coastal regions of the Mediterranean (Catalonia, Valencian Community, Murcia and the eastern part of Andalusia, where the presence of the tiger mosquito has been consolidated) during the months of summer.
Dengue is also caused by a virus and is also transmitted primarily by Aedes aegypti, but also by the tiger mosquito. Among its main symptoms are fever, headaches and joints and muscles, rash and vomiting. Until now all cases registered in Spain were "imported", but the expansion of the tiger mosquito could result in the emergence of native cases, as they have already taken place in France, Portugal, Italy and Croatia.
It is also a disease caused by a virus, transmitted mainly by the same mosquitoes as dengue and Zika. Its main symptoms are very strong pain, both headache and muscle and in the joints. The word chikungunya comes from the maconde people, who inhabit a plain between Mozambique and Tanzania, and means "to walk crooked or hunched over", which was what they did, due to pain, who suffered from the disease.
Most of the cases registered in Europe are, as with Zika and dengue, imported. But not all: in Italy there were at least 14 autochthonous cases confirmed in 2017. And also in the French region of Provence-Alpes-Côte d'Azur the existence of cases originating there was proven. The person responsible, of course, is the tiger mosquito, which is also widespread in these areas, which places Spain also at risk.
4. Yellow fever
It is transmitted by the same mosquitoes as the previous ones. In fact, one of the names by which Aedes aegypties is known as "yellow fever mosquito". Fortunately, it is still a strange disease in our country. But it is endemic in the tropical areas of Africa and Latin America, which forces us to be attentive also to the possibility of arriving in Spain.
Malaria includes flu-like symptoms, along with high fevers, chills and anemia. Its vector is another mosquito: the Anopheles, which was also believed to be eradicated but has slowly returned to Europe. In 2010, the first indigenous case was registered in Spain in almost half a century (the previous one dated from 1961), and in February of this year a three-month-old baby was diagnosed with the disease that had not visited any endemic area.
It is true that the bites of this mosquito are not the only possible cause of infection: it can also be due to a cross contamination of materials and fluids in a health center, as well as a transfusion of infected blood or an organ transplant. But the risk of mosquitoes spreading the parasite exists.