The arrival to the American continent of a new variety of mosquito, known as Aedes Vittatus, has the Costa Rican health authorities on alert. Although this insect has not reached Costa Rica yet, its presence is confirmed in the Dominican Republic, some places in Cuba, and in several places in the United States.
The other Aedes-type mosquitoes that are in the American continent are Aegypti and Albopictus. All three have in common that they can transmit diseases such as dengue, chikungunya, Zika and yellow fever.
Not yet, but …
There are reports of the presence of this variety of Aedes in Europe, Africa and Asia. Rodrigo Marín, national coordinator of Vector Surveillance of the Tico Ministry of Health, pointed out that Aedes Vittatus is an invasive species and of which, until now, very little is known. “In Costa Rica we have not found it. (…) We have constant monitoring at the national level,” he said.
Do the insects compete with each other?
Adriana Troyo, a vector researcher at the University of Costa Rica (UCR), said that there are several conditions that can contribute to its movement from one place to another. She recalled that neither the Aedes Aegypti nor the Aedes Albopictus originate from America.
“This is a phenomenon that has occurred in recent decades, because we are more globalized, it is logical to think that the transport, for example, of goods and objects where mosquitoes or larvae or eggs can come, eventually if they are in water, they could come live and settle in a new area, being very similar and occupying the same hatcheries, sometimes they can compete with each other”, she explained.
“It may be that they are detected in an area and then disappear and that is because those around it manage to overshadow and it ends up disappearing due to competition. So in this case it will be necessary to see how this mosquito acts in the presence of both Aedes Aegypti and Aedes Albopictus”, the specialist stated. She reviewed that the three could be in the same place, but in different niches.
Similarities and differences
Among the similarities shared by the three mosquitoes, the expert highlighted that: All three belong to the genus Aedes. They are species introduced to the continent. In terms of behavior, from a very general point of view, females lay their eggs in places such as holes in stones, trees and other natural hollow-type hatcheries.
Aedes Aegypti and Aedes Albopictus adapted to man-made breeding sites such as tires, vases, buckets, barrels and others that have walls and water. The quintessential breeding ground for Aedes Vittatus are puddles like a hole in the ground, caused by animal footprints, bamboo trunks and trees, among others. Both Albopictus and Vittatus bite mammals and people, while Aegypti have a preference for humans.
“Between them there are more differences of type in how the mosquito looks. In behavior as such they can be very similar. Just as they are all voracious, because when they are hungry they are very stupid and they persecute everything” explained Troyo.
On the issue of difference, which one is more dangerous?
For Troy, of the three mosquitoes, Aedes Aegypti is the number one transmitter, when it comes to dengue, Zika and Chikungunya. “Aedes Aegypti is the transmitter par excellence of human viruses, such as dengue, because as it bites humans, it transmits the virus very well. Aedes Albopictus can also transmit dengue if there are many people and a lot of mosquitoes, and Aedes Vittatus apparently also has the ability to transmit dengue”, said Troyo.
All three, in addition to dengue, Zika and Chiknguña, can infect people with yellow fever, but in the case of Costa Rica there have been years in which there are no cases of this disease. She argued that Aedes Vittatus is related to the transmission of yellow fever in some areas of Africa.
In Troyo’s personal criteria, “given the transmission that already occurs with Aedes Aegypti, dengue, Zika and chikungunya, the inclusion of Aedes Vittatus will hardly lead to dengue cases in larger epidemics, I don’t think so.”
For his part, Rodrigo Marín agrees that the most risky vector is Aedes Aegypti and Albopictus second. That is why he recommended to the population to eliminate the possible breeding sites that these mosquitoes could use to reproduce and not leave the way free for transmission.