Medical Xpress – Unknowns, dangers and surprises persist about dengue viral infection and now an assumption once accepted as conventional wisdom about immunity to the mosquito-borne disease may be incorrect.
New research involving epidemiological models and data from more than 4,400 people in Nicaragua suggests that it’s time immunologists developed a new framework to understand population immunity to dengue.
For decades, it was believed that once you were infected with dengue virus, the immunity lasted for life.
The dogma persisted in the face of observational data, which found that people who were previously infected were more susceptible to severe dengue if infected again.
But an international collaborative group of researchers has now conclusively shown that immunity not only wanes, it tends to wax and wane—a discovery that reveals dengue infection to be far more complex than previously thought.
“Dengue is the most common virus spread by mosquitoes, infecting as many as 390 million people annually worldwide.”
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“Infection with multiple dengue virus serotypes is thought to induce enduring protection against dengue disease,” writes Rosemary A. Aogo, lead author of a new research paper published in Science Translational Medicine.
“However, long-term antibody waning has been observed after repeated dengue infection,” Aogo added, referring to her team’s new findings.
The waning of antibodies inevitably was followed by a boosting of antibodies when the next epidemic came along, Aogo and colleagues found.
Her team’s discovery allowed the construction of a new model that best describes population vulnerability to dengue infection, especially amid the known periodicity—the cyclic nature—of dengue outbreaks.
When it comes to dengue, people are not permanently immune but susceptible to infection, then immune and ultimately susceptible again. Hence, Aogo and her team’s newly proposed model: “susceptible-infected-recovered-susceptible.”
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Dengue is a devastating viral infection transmitted to humans through the bite of Aedes aegypti mosquitoes—flying hypodermic needles that descend prolifically during significant outbreaks … read more.