Asymptomatics Sneak Dengue to Others, Dominate Transmission Cycle
A thriving mosquito-borne virus, Dengue has been on the rise in recent years- it has spread unnoticed as asymptomatic cases may have contributed to the transmission cycle. It is the world’s fastest-growing infectious disease, unleashing its dread on hundreds of millions of people worldwide- it causes half a million life-threatening infections with a mortality statistic of about 20,000 individuals, who are mostly children, annually.
Now, a new study by research
ers at the University of Notre Dame indicates that more than 80 percent of dengue virus infections are attributable to individuals with mild to no symptoms who do not seek treatment from a physician.Their investigation further indicates that nearly a quarter of dengue virus transmission is the result of mosquitoes infected already infected individuals before the onset of symptoms. And by the time those symptoms appear, the window to prevent the virus from spreading has passed.
“Until a few years ago, it was assumed that individuals with mild to no symptoms contributed relatively little to dengue virus transmission,” said Alex Perkins, Eck Family Assistant Professor of Biological Sciences at the University of Notre Dame and senior author on the study.
“Our research reveals that people showing no symptoms of dengue virus infection are contributing much more than was previously recognized so that we now have a better idea of the large extent to which they contribute to the spread of this disease.”
The study employed a mathematical model to quantify what fraction of dengue virus infections might be caused by these asymptomatic people whose illnesses go undetected by public health surveillance systems.
Their investigation involved integrating data sets on quantifying the viruses in blood during different stages of infection, the severity of symptoms with respect to previous infections and the proportion of infections resulting in clinical consultation.
“Unfortunately, based on our study, those who need to be targeted with interventions are either being identified after they have already contributed to transmission or are not being identified at all,” said Perkins. “Our results indicate that it might be necessary to shift emphasis toward more proactive disease prevention strategies that do not rely as strongly on responding to detected cases.”
