Mosquito saliva can weaken body's defenses against dengue virus

Dengue has spread in tropical and subtropical areas such as Southeast Asia, Africa and Latin America. The new discovery, scientists explain why the disease is so easily transmitted and could eventually lead to new ways to prevent infection. It is remarkable how clever these viruses are they subvert mosquito biology to tamp down our immune responses so that infection can take hold. Approximately half the world's population is at risk for dengue, and roughly 400 million people are infected every year. Dengue's symptoms, including fever, nausea, and skin rash, are often mistaken for other diseases. Most people will have mild cases, but about 1 in 20 will develop severe illness that can lead to shock, internal bleeding and death. Unfortunately, it's possible to contract dengue repeatedly, as it is caused by four related viruses transmitted primarily by the Aedes aegypti species of mosquito. There is no treatment, but the new discovery identifies an important contributor to the disease's spread as researchers seek to find better ways to combat it. The scientists found that infected mosquitoes' saliva contained not just the expected dengue virus but a powerful conspirator: molecules produced by the virus that can blunt the body's immune response. The injection of these molecules, called sfRNAs, during the mosquito bite makes it more likely that the victim will become infected with dengue. Scientists who study mosquitoes previously had suspected that the insects' saliva might contain some type of payload to enhance the potential for infection. The new findings pinpoints one weapon in the viruses' arsenal and opens the door to finding new ways to help reduce transmission and control the disease's spread. For now, the best way to avoid getting seriously sick with dengue remains to avoid getting bitten. These findings provide new perspectives on how counteract dengue virus infections from the very first bite of the mosquito.

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                        Exercise help counteract genetic risk of disease

The study found higher levels of total physical activity, especially moderate- to vigorous-intensity physical activity, had a strong association with a lower risk of developing type 2 diabetes. The researchers said that the study demonstrates higher levels of physical activity should be promoted as a major strategy for type 2 diabetes prevention. The study involved 59,325 adults who wore accelerometers (activity trackers worn on their wrist) at the start of the study and were then followed for up to seven years to track health outcomes. This included genetic markers associated with a higher risk of developing type 2 diabetes. People with a high genetic risk score had 2.4 times the risk of developing type 2 diabetes when compared with those with a low genetic risk score. The study showed more than an hour of moderate- to vigorous-intensity physical activity per day was associated with a 74 percent lower risk of developing type 2 diabetes when compared with participants who did less than 5 minutes of physical activity. Researcher are unable to control our genetic risk and family history, but this finding provides promising and positive news that through an active lifestyle, one can 'fight off' much of the excessive risk for type 2 diabetes. Diabetes is a global public health concern. In 2021, there were 537 million adults living with diabetes worldwide. This study will inform public health and clinical guidelines so that it can help chronic disease prevention. Research results with a broad audience to let people know that physical activity is health-enhancing, especially for people with high genetic risk..

SOURCE: Science Daily News, June 2023

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                              Impact of maternal stress during pregnancy on child's health

Prenatal maternal stress life events are associated with adverse neurodevelopmental outcomes in offspring. Biological mechanisms underlying these associations are largely unknown, but a chemical reaction in the body in which a small molecule known as a methyl group gets added to DNA, called DNA methylation, likely plays a role, according to researchers. These findings could provide new insights into how the fetal environment potentially influences not only neurodevelopment, but metabolism and immunologic functions as well. More than 5,500 people took part in the study with that population broken down into 12 separate cohorts. The research examines five separate categories of stress that expectant mothers face during pregnancy. They are financial stress, conflict with a partner, conflict with a family member or friend and death of a friend or relative, plus a cumulative score that combines all the categories. Researcher found that when a mother experienced a cumulative amount of stress during pregnancy, there was, in fact, an association with DNA methylation in umbilical cord blood, which is a kind of epigenetic modification in the baby that's developing in the womb. An epigenetic modification is something that doesn't change the sequence of the DNA, however the DNA is modified which is something that's dynamic and can change in response to environmental exposures. Therefore, it's something that can be turned on or off later in the child's life or something that can maybe not do anything, it's still unknown. It's thought to be a mechanism of gene expression control. Epigenetic modifications are a very dynamic process, there are a lot of changes that can happen in response to environmental factors. What you're seeing biologically at the beginning of fetal development you might not see the outcome of until later on during a child's development. It's fascinating as a biologist to begin to uncover some of the biological clues to how neurodevelopment is affected during fetal development.

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     Obesity increases risk of mental disorders throughout life

Researchers analyzed a population in order to determine the relative risks of comorbidities in obesity and identify statistically significant sex differences. Consequently, it became evident that an obesity diagnosis significantly enhances the likelihood of a wide range of mental disorders across all age groups including depression, nicotine addiction, psychosis, anxiety, eating and personality disorders. In order to find out which illness typically appeared prior and subsequently to the obesity diagnosis, Researher had to develop a new method. This allowed the researchers to determine if there were trends and typical patterns in disease occurrence. In case of all co-diagnoses, with the exception of the psychosis spectrum, obesity was in all likelihood the first diagnosis made prior to the manifestation of a psychiatric diagnosis. The researchers found significant gender differences for most disorders - with women showing an increased risk for all disorders except schizophrenia and nicotine addiction. While 16.66% of obese men also suffer from nicotine abuse disorder, this is only the case in up to 8.58% of obese women. The opposite is true for depression. The rate of diagnosed depressive episodes was almost three times higher in obese women (13.3% obese; 4.8% non-obese). Obese men were twice as likely to be affected (6.61% obese; 3.21% non-obese).At present, obesity is a highly prevalent disease worldwide and affects more than 670 million people. The fact that the disease promotes metabolic disorders and serious cardio-metabolic complications) has already been extensively researched. Since this study now also shows that obesity often precedes severe mental disorders, the findings underscore its importance as a pleiotropic risk factor for health problems of all kinds. For this reason, thorough screening for mental health problems in obese patients is urgently needed to facilitate prevention or ensure that appropriate treatment can be given.

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