AsianScientist (Nov. 05, 2025) – As mosquito habitats broaden, the ailments they carry additionally journey with them. Altering climate patterns make it potential for mosquito-borne ailments like dengue to unfold into beforehand unaffected areas.
One such space is Nepal, which has seen a current surge in dengue infections. Nepal has robust vaccine measures in opposition to one other mosquito-borne illness, the Japanese encephalitis virus (JEV). Nonetheless, dengue prevention nonetheless depends primarily on mosquito management and private safety measures.
“Japanese encephalitis is a devastating illness that causes a a lot heavier well being burden than dengue fever, which is often much less lethal however nonetheless harmful. What makes Japanese encephalitis totally different is that it may be virtually fully prevented with vaccination, whereas dengue nonetheless has no extensively obtainable vaccine,” stated Professor Patrick Tan, Senior Vice-Dean for Analysis at Duke-NUS Medical Faculty.
A current examine has discovered that these whose immunity to JEV has declined over time are extra inclined to extreme signs when contaminated with dengue. This examine, carried out by researchers from Duke-NUS Medical Faculty in collaboration with scientists in Nepal was revealed in Science Translational Medicines.
“We selected Nepal as a examine web site as a result of it’s one of many few international locations the place dengue is spreading shortly in a inhabitants that already has widespread immunity to a different flavivirus, Japanese encephalitis. This gave us a singular likelihood to see how prior immunity shapes dengue sickness. We discovered that folks whose Japanese encephalitis immunity had waned have been extra more likely to develop into severely in poor health from dengue,” stated lead writer Sidharth Malhotra, Analysis Fellow at Duke-NUS Medical Faculty.
The workforce examined over 500 sufferers, measuring chymase ranges of their blood as an indicator of irritation and dengue severity. Sufferers with solely average ranges of JEV antibodies had the best chymase ranges, whereas additionally being extra more likely to endure from harmful bodily signs like bleeding and abdomen ache.
The explanation for this phenomenon is likely to be antibody-dependent enhancement, a mechanism the place antibodies from a earlier an infection or vaccination are too weak to fight a brand new viral an infection, however nonetheless bind to the viruses. As an alternative of neutralising the virus, this helps it to enter immune cells and replicate quickly, triggering a stronger immune response that may trigger extra extreme signs.
This phenomenon is well-documented in sufferers who’ve been contaminated with dengue a number of instances, however these findings now present that it could actually additionally happen with fading immunity to associated viruses like JEV.
“This discovery issues for international locations like Nepal and throughout Asia the place each viruses flow into. It additionally highlights the necessity to preserve JEV safety robust, by well-timed booster pictures, not solely to stop Japanese encephalitis itself but in addition to cut back the chance of extreme dengue,” stated Affiliate Professor Ashley St. John of the Programme in Rising Infectious Illnesses at Duke-NUS Medical Faculty.
The researchers plan to proceed monitoring the evolution of dengue within the area, working with companions to develop efficient vaccination methods in opposition to JEV, dengue, and different associated viruses.
Affiliate Professor St. John stated, “Sustaining robust JEV vaccine protection and probably introducing booster pictures when wanted might be a sensible option to not solely forestall JEV but in addition cut back the severity of dengue, serving to defend populations in Asia the place each viruses are current.”
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Supply: DUKE-NUS Medical Faculty; Picture: Kateryna Kon/Shutterstock
This text might be discovered at: Dengue illness severity in people is augmented by waning Japanese encephalitis virus immunity
Disclaimer: This text doesn’t essentially mirror the views of AsianScientist or its workers.
