Deforestation and the resulting loss of biodiversity is making mosquitoes more dependent on human blood to live.
Mosquitoes in some regions of Brazil are becoming more dependent on human bloodas environmental degradation reduces the availability of other animal hosts, according to new research that raises concerns about the future spread of mosquito-borne diseases.
One carried out in the Brazilian Atlantic Forest and published in the scientific journal Frontiers in Ecology and Evolution found that, with the decline in biodiversity, mosquitoes are more likely to feed on human blood.
Researchers warn that this change, driven mainly by deforestation and due to urban expansion, it can have serious consequences for public health, since mosquitoes are important vectors of diseases such as dengue, zika and yellow fever, says .
The research team, from the Federal University of Rio de Janeiro and the Oswaldo Cruz Institute, carried out fieldwork in two natural reserves within the Atlantic Forest, one of the most biodiverse and, at the same time, most threatened ecosystems in the world. Using light traps, they captured more than 1700 mosquitoesrepresenting 52 different species.
From this sample, scientists identified 24 female mosquitoes that had fed on blood, whose blood meals could be genetically analyzed. The results showed a notable preference for humans: traces of blood from 18 different people were detected. Birds were the second most common source, with blood from six birds being identified, while amphibians, rodents and canids appeared only once each.
“These findings show that the species of mosquitoes that we captured in the remnants of the Atlantic Forest have a clear preference for feeding on humans,” said Jerónimo Alencar, biologist at the Oswaldo Cruz Institute and one of the authors of the study.
Researchers say the most likely explanation is the loss of wildlife caused by deforestation and the expansion of human activity. As natural habitats shrink, mosquitoes have fewer animal hosts to feed on and increasingly turn to humans, who are generally the most abundant and accessible source of blood.
“With fewer natural options available, mosquitoes are forced to look for new alternative sources of blood,” said Sérgio Machado, a microbiologist at the Federal University of Rio de Janeiro. “They end up eating more humans for convenience, since we are the most prevalent host in these areas.”
This change is worrying because the increase in human nutrition could amplify disease transmission infectious. When mosquitoes bite humans more frequently, the risk of outbreaks increases, particularly in densely populated areas or areas with poor services.
The researchers warn that more studies are needed to confirm and expand their findings
