IberiaNature A guide to the natural history of Spain
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Tiger mosquitoes and the history of yellow fever and dengue in Spain

18 December 2005 update
Tiger mosquito reaches
Altafulla in Tarragona

16 September 2005 

Tiger Mosquito detected in Barcelona. The Catalan Health Authority has detected the presence of the Tiger Mosquito in Can Baró in Barcelona, after several people complained of painful mosuito bites. Leaflets are to be distributed throughout the city.
(El Pais)

21 February 2005

According to scientists, the nascent Sant Cugat tiger mosquito colony seems to be here to stay. Since the mosquito's arrival in Sant Cugat near Barcelona in August 2004, it has spread out homogenously across the whole municipality with ‘very high' population densities comparable with those in Italy, despite a campaign to reduce potential breeding sites (plant pot saucers, garden fountains, hollow tree trunks, etc- up to 400 larva can hatch in one of these sources). The tiger mosquito has now been detected on the borders of Sant Cugat, moving into the adjacent municipalities of Barcelona , Sant Quirze, Rubí, El Papiol, Molins de Rei and Cerdanyola, the latter being the second Spanish town affected. Concerns, no doubt with a tad of hysteria, are being raised that the tigers could affect the economy and tourism. There are instances of families deciding to move out of the area, fleeing from their painful bite. Whatever the case, the mosquito is clearly going to continue to expand. Scientists predict its arrival to Valencian coasts at some time this year, and it is probably only a matter of time before it is present along the entire Mediterrenean strip. Its speed and virulence will depend on how effective government action is. In Rome local government spends 3.5 million a year just to keep the population under check. It is, it would seem, impossible to erradicate.

September 17, 2004

The first colony of tiger mosquitoes ( Aedes Albopictus – mosquito tigre ) has finally been detected in Spain, in Sant Cugat de Valles near Barcelona. Mosquito experts have been expecting the insect to reach here for some time. It has been spreading across Europe and reached Italy and France in 1990. The television and the press have reported dozens of people complaining of “intense” painful bites. Robert Eritja an entomologist with the Baix Llobregat Control Service explained that the insect poses no public health risk. He added that the tiger mosquito is extremely aggressive, attacks by day and lives in gardens where they breed in stagnant pools of water. It cannot be eradicated but it can be controlled”.

There are as yet no known cases in Europe of vector-spread diseases from a tiger mosquito. However, although at this moment they may not be harmful, there is cause for concern. The tiger mosquito can be a vector for a whole litany of major diseases including dengue and yellow fever and West Nile. Aedes albopictus began to spread out from its Asian homeland in the 1970s, above all thanks to the sea transport of tyres. Moreover, the parent species Aedes aegypti , present as a result of previous ship-borne invasions, was the vector which caused severe outbreaks of dengue and yellow fever several centuries ago throughout the Mediterranean, though it was later eradicated. Both Aedes albopictus and Aedes aegypti share a similar habitat type and bionomics* and bear the same vector diseases.

The first outbreak of yellow fever in Spain was in 1701. It would remain an endemic killer for 180 years, particularly in the southern ports. A single chain of yellow fever outbreaks between 1800 and 1803 claimed more than 60,000 lives in Cadiz, Seville and Jerez. Barcelona was severely hit between 1822 and 1824 with 80,000 people infected, of which 20,000 died. 300,000 people are believed to have died from yellow fever in Spain during the 19th century.

Epidemics of dengue (incidentally, the word is Spanish in origin) in Spain are not as well documented as Yellow Fever. The first known outbreak was in Cadiz in 1778. The mortality was so low that the disease was popularly known as ‘ La Piadosa' (‘the compassionate one'). The last documented case of Aedes aegypti was collected in Barcelona centre in 1939 (Margalef 1943, who described the species as “very common”). It continued to be considered common by Spanish researchers well into the 1950's. The reasons for its disappearance from almost the whole Mediterranean are unclear. Sanitation and better ships are cited as factors. It would seem that wetland drainage, so effective against malarial-vector anopheline mosquitoes had little effect on this urban dweller.

Let me make one thing clear. One thing is the mosquito and another quite different thing the disease. As long as a Spanish mosquito does not itself become infected by a disease, it obviously cannot pass it on to a human being. The infection zones of neither dengue or yellow fever are currently anywhere near the Iberian Peninsula.

*The branch of biology concerned with the relationships between organisms and their environment

Click here for excellent article written in dodgy English in pdf on the subject (most gleaned from here)