Covering Japanese resistance to encephalitis associated with a more serious dengi disease

Scientists from the Duke-Nus Medical School, in cooperation with scientists in Nepal, said that reducing the resistance to Japanese encephalitis virus (JEV) can increase the risk of a more severe dengue disease in humans. Published in the journal, the study emphasizes how disappearing protection of the vaccine from one virus may inadvertently affect the body’s reaction to another.

Japanese encephalitis is a serious disease that kills about 25 percent of people who develop severe symptoms and can leave many people with long -term disability. Denga is also a serious problem of public health, because the fastest growing viral disease transmitted by mosquitoes around the world, capable of causing a serious illness and even death, and cases have increased rapidly in Nepal in recent years. Fortunately, Japanese encephalitis can be prevented by vaccination, and countries like Nepal have made significant progress in mass vaccination campaigns. However, preventing dengi still depends primarily on mosquito control and personal protective equipment. Although JEV vaccinations generate a high level of antibodies, immunity can decrease over time, especially without resembling doses.

Scientists have examined over 500 patients for five years in Nepal, one of the few countries where both Jev and Denga are actively spreading. The team discovered that people who in the past were vaccinated against Jev, but whose level of antibodies has fallen, more often experience severe symptoms when they later entered the deng. In this way, this did not affect people with strong JEV resistance.

We chose Nepal as a place of study, because it is one of the few countries where the dengue is spreading quickly in the population, which already has a wide resistance to another Flavivirus, Japanese encephalitis. This gave us a unique opportunity to see how earlier immunity shapes the disease of the Dengi, and we found that people whose resistance to Japanese encephalitis has decreased, it is more likely that they seriously fall ill with dengi. “

Dr. Sidharth Malhotra from the program in the emerging infectious diseases in Duke – Nus Medical School and the main author of the study

One of the important reasons for this result seems to be a process known as strengthening through antibodies, in which the partially effective antibodies attract and deteriorate dengue. This happens when antibodies from the previous infection or vaccination are not strong enough to fully neutralize another virus, but still bind to it. These partially effective antibodies can help in the easier input of the Dengi virus, which can allow the virus to grow faster and cause a stronger immune response. That a stronger immune response may cause greater inflammationcontributing to more severe symptoms.

Although this mechanism has been well examined in people with many dengius infections, a new study shows that this can happen when resistance to another, but related virus, such as JEV. These discoveries offer a new insight into how the cross resistance between related viruses can shape health results.

A team of scientists assessed how serious the dengi disease became by measuring the levels of Chymase, a marker in the blood that increases during inflammation and is associated with more serious diseases. They discovered that Chymase levels were much higher in patients who had only a moderate JEV antibodies. These people more often showed signs that denga is becoming more and more dangerous, such as bleeding, abdominal pain and fluid leaking into the surrounding tissues, which are signs that suggest that Denga is progressing towards its more dangerous forms.

Extraordinary professor Ashley ST John, from the Duke-Nus Medical School program in emerging infectious diseases, which conducted the study, commented: “This discovery is important for countries such as Nepal and Asia, in which both viruses circulate. Both viruses circulate. This also undermines the need to maintain JEV protection, through the excreted shots, not only for prevention. Japanese smoking inflammation, but also to reduce severe deng.

Associate prof. Ashley believes that this knowledge can benefit millions of people living in regions where JEV or travelers are required who must take the JEV vaccine. “Maintaining a strong JEV vaccine coverage and probably introducing reminiscent photos, if necessary, can be a practical way not only to prevent Jev, but also to reduce the severity of the dengi, helping protect populations in Asia, where both viruses are present.”

The new arrangements are particularly important because climate change and urbanization increase the spread of mosquito disease. Over the past decade, Nepal has recorded a rapid increase in dengi cases, including in areas where the virus was not previously widespread. Changing weather designs and the expanding mosquito habitats help diseases such as dengue reaching new regions.

Professor Patrick Tan, senior deputy research on Duke-Nus research, added: “Japanese encephalitis is a destructive disease that causes a much more severe health burden than dengi fever, which is usually less deadly, but still dangerous. What makes Japanese encephalitis differ that you can almost prevent a vacuum, but there is no preventing vacuum. permanent protection has a double benefit. “

As part of the ongoing work, the team plans to monitor how denga evolves in the region, especially as a larger number of viral strains circulated, and the immune landscape of the population becomes more complex. They also cooperate with partners to model the most effective vaccination strategies to protect the community against dengue and related viral infections.

This study was supported by Singhealth Duke-Nus Global Health Institute and Singapore Ministry of Education.