The hitchhiker insect, as the entomologist Paul Reiter has described the tiger mosquito, years ago abandoned its origins, in Asia, and began to travel around the world. Reiter has traveled the globe likeHunterof insects. After working at the Centers for Disease Control and Prevention (CDC) in the United States, today he directs the department of Infectious Diseases Transmitted by Insects at the Pasteur Institute in Paris. He knows what it’s like to deal with this fierce biter, theAedes albopictus, whose presence has been found in 40 countries on five continents. TheTiger, which is very resistant to the cold, has made the leap to the old continent and has been in Spain since, in 2004, it settled near Barcelona. “The tiger mosquito we have in Europe probably comes from Japan, where the winters are very harsh,” says Reiter. “Before the cold, their eggshibernanand they are able to survive. “
It was Reiter who discovered that theTigerhad settled in the United States. In 1983, in a cemetery in Memphis, Tennessee, he came across a specimen on a tree leaf. How had he traveled tens of thousands of miles from Asia to Elvis’s birthplace? The answer came two years later, when his presence was confirmed in Harris County, Texas. This time he was roaming at ease in a graveyard of used wheels. “So muchAedes aegypti-the yellow fever mosquito- asAedes albopictus-theTiger– they breed in the woods, but tires are a good substitute for tree branches. The rubber collects water, allows the larvae to feed, insulates from light and conserves moisture. In that area of Texas many companies were importing tires from Japan and exporting them to other countries. “TigerHe had managed to travel in the containers on the wheels.
Yes, this insect is as fierce as they paint it
The peculiar surname of the tiger mosquito is not accidental and is due to the black and white bands on its abdomen. Another good reason for its feline nickname is its fierceness. The bite of this insect, which is only five millimeters long, makes people’s lives outside their homes “really unbearable,” says Reiter. There are other mosquitoes morerespectful, WhatAedes aegypti, which has a very fine proboscis and usually injects an anesthetic to minimize pain. ButTigerdoes not know of subtleties. “The difference is the same as between being pricked with a needle or a knife,” says the expert. Ask the Romans, whose city is invaded by the bug. “The hotels have to keep the doors closed since, if not, it attacks the people at the reception. Even in the Vatican they have problems,” says the scientist.
TheTigerit is a global invader. A quarter of a century after arriving in the United States, it has settled comfortably in 36 of its states and “has even survived the terrible Chicago winters,” Reiter explains. And from there it has passed to South America. In 1986 it was detected in Sao Paulo (Brazil) and spread through the southeast of the country. AccordingScience, reached Mexico in 1993 and two years later El Salvador, Guatemala and Honduras. In 1998 it was extended to Argentina, Colombia and Paraguay, and Panama and Nicaragua surrendered in 2002 and 2003, respectively. His African adventure has been confirmed in Cameroon, Equatorial Guinea, Nigeria and Gabon. In 1979 Reiter detected it for the first time in a European country, Albania, and its evolution has been unstoppable. “Italy imported it in the early 1990s and then it went to Switzerland, southern France, Croatia and the former Yugoslavia. I have no doubt that it will arrive in Paris very soon.”
They stow away and nest in wet areas
Spain has not gotten rid of this “small, aggressive and very voracious” insect, as explained by Rosario Melero-Alcíbar, from the Parasitology Service of the National Center for Microbiology in Majadahonda (Madrid). This expert tracked the mosquito in several municipalities in Catalonia, especially Barcelona and its surroundings, and found it in 19 towns, some as touristy as Sitges. The mosquito settled in 2004 in San Cugat del Vallés, where it is likely that it came by car from other European towns. “It is enough to leave the window open for twenty minutes for it to sneak in,” says Melero-Alcíbar. This also explains how he emigrated from Barcelona to Tarragona to travel even in the trunk. Their eggs – a female is capable of laying 80 at a time – survive despite the dryness because they decrease their metabolic activity until there is moisture. Another of its means of transport is the “lucky bamboo”, an ornamental cane of Chinese origin whose most commercialized species is theDracaena sanderiana, which sells for millions in the United States. The insects lodge inside their trunks and branches, which twist into original figures. There are reports of bites suffered by workers who load the containers for transport and in the greenhouses where they are raised. Here theTiger“It is a plague, so it is possible that in this way it has been introduced into Spain”, suggests Reiter.
Melero-Alcíbar admits that the situation in Barcelona and its surroundings is “difficult”. ThetigersThey nest in damp dishes, flowerpots or water accumulated in containers in gardens. Reiter is more blunt: “I would say that it is impossible to eliminate.” This expert compares the scenario with that of theAedes aegypti, “a semi-domestic species that does not live more than fifty meters from people and constitutes an easier target for its control or fumigation. The tiger mosquito, on the other hand, is quite inaccessible.” He travels to chop, but he settles away from the houses whose inhabitants he tortures. In 2002 Reiter had to cope with a dengue epidemic – a fever that causes muscle aches and bleeding – that affected 122 people on the Hawaiian island of Maui. “There were a lot of tiger mosquitoes in the towns where the outbreak occurred. I remember a complex with golf courses that belonged to former Beatle George Harrison. I started walking around to see if I could find any of these.albopictusnear the houses. I walked a kilometer away and I couldn’t bear it, they were eating me alive. It is a very aggressive species and difficult to control because it does not need the proximity of people. “
Due to its resistance and mobility, the transmission of infections is understood. Research has shown that this insect can spread up to twelve different types of viruses. Experts believe thatAedes albopictustransmits a less virulent variety of dengue than its cousin, theAedes aegypti, which is the main vector of the virus.
His indiscriminate voracity makes him less dangerous
Reunion Island, east of Madagascar, in the Indian Ocean, suffered an epidemic outbreak of Chikungunya fever in 2006, the name of which means “walking doubled over” in some African languages. TheTigerwas the transmitter of this virus that causes fever, hives and joint pain. In just 14 months, more than 266,000 people were infected on the island, and the following year a small outbreak in Italy affected 200 and killed an elderly woman. Their threat continues to be a cause for attention today, although not for alarm. “The animal is a good vector of diseases in Asia, but not outside its habitat,” says Meleros-Alcíbar.
Some studies suggest that the insect could spread yellow fever and other viruses called arboviruses. In the laboratory, Paul Reiter and his team cultivated cell lines derived from the mosquito itself, infected them with different types of viruses and thus proved that the cells of theTigerthey were quite susceptible to infection. “That does not necessarily mean that it is a good vector, for this many factors must be present,” says the researcher. First of all, the behavior of the insect must be taken into account. “For a mosquito to transmit a virus, it first has to suck infected blood and after an incubation time its salivary glands are infected. When the mosquito pierces the skin, it expels saliva, which reaches the blood capillaries with the viruses that infect the Therefore, a period of time passes from when the mosquito acquires its infectious dose until it becomes contagious, “he explains.
The tiger mosquito bites many different creatures and is not as specific to humans as theAedes aegypti, ateetherof primates. Butalbopictusit attacks everything that moves. “If you have a cat in the living room, it will probably bite him before you,” says Reiter, “which makes it a secondary vector for virus transmission.” It is a consolation, although his pecks will continue to make you cry out in pain.
Luis Miguel Ariza
