Dengue virus infects 390 million people worldwide each year through the bite of mosquitoes of the Aedes genus. But estimates suggest that 300 million of these people do not present any clinical symptoms that are severe enough to be detected by health care systems. It was previously thought that these asymptomatic or mildly symptomatic infections did not reach a high enough level of viremia to infect mosquitoes.
However, a new study by scientists at the Institut Pasteur in Cambodia, the Institut Pasteur in Paris and the CNRS has revealed that the dengue virus can be spread back to mosquitoes by asymptomatic carriers, who are actually more infectious than those displaying symptoms.
The research team provided proof that people infected by dengue virus but showing no clinical symptoms can actually infect mosquitoes that bite them. It appears that these asymptomatic people - who, together with mildly symptomatic patients, represent 75% of all dengue infections - could be involved in the transmission chain of the virus.
The study is published in PNAS.