Scientists explains the attack of coronavirus on the brain in new study - Pragnya IAS Academy - News Analysis.

Scientists explains the attack of coronavirus on the brain in new study.

The peak viral load in the brain was 1,000 times than in lungs

Very high levels of the novel coronavirus were found in the brain of mice infected in a controlled exposure study by scientists from Georgia State University in Atlanta.

The peak viral load in the brain was 1,000 times than in lungs, suggesting that the coronavirus has a high potential for replication in the brain.

The research also showed a direct correlation between high viral load in the brain and the onset of neurological symptoms and deaths in the infected mice.

“Brain infection leads to immune cell infiltration, inflammation and cell death,” the report concluded. It also noted that humans have a higher chance of developing a brain infection with a high dose of the virus

The researchers collected a strain of the virus from the throat swab of a patient in Washington and introduced it into the mice through their noses.

Upon entering, the virus made its way to the brain by infecting the nasal passageway, olfactory bulb (responsible for the sense of smell) and eyes, the study suggested.

The infected subjects were observed for six days by which time all of them succumbed to the infection. The report was published on January 19 in the journal Viruses.

While the occurrence of neurological complications from COVID-19 was well known, its pathogenesis was not well understood, the authors of the report wrote.

High concentration of the virus was found in the lungs from the first day of the infection and declined during the last phase (days five and six). In the brain, however, the viral load increased only in the last stage —the highest levels were observed on days five and six.

This also when the infected mice displayed neurological symptoms such as hunchbacked posture, ruffled fur, tremors and ataxic gait.

Immune response in these two murine organs also followed the same timeline. The levels of interferons, proteins secreted by the immune cells of the body, were found to be higher in the lungs than the brain despite higher virus replication in the brain.

The scientists also studied the viral load and immune response in other organs of mice like heart, kidney, spleen, pancreas and liver. Replication of coronavirus in these organs was found to be limited. (Source: downtoearth)

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Scientists explains the attack of coronavirus on the brain in new study.

Air pollution lowers brain function, can lead to lower verbal and maths scores: Study - Pragnya IAS Academy - News Analysis.

Air pollution lowers brain function, can lead to lower verbal and maths scores: Study.

The world’s top 20 most polluted cities, according to the World Health Organization’s (WHO) database, are in developing countries. Almost all the cities in low- and middle-income countries with more than 1,00,000 residents fail to meet WHO air quality guidelines.

Long-term exposure to air pollution lowers brain function, which reflects in decreased verbal and mathematics scores, apart from causing heart disease and breathing problems, a new study from China has said.
“... a narrow focus on the negative effect on health may underestimate the total cost of air pollution. Our findings imply that the indirect effect of pollution on social welfare could be much larger than previously thought,” Xiaobo Zhang, one of the authors of the paper, said.
The study retrospectively analysed data of nearly 32,000 people from two waves (2010 and 2014) of the China Family Panel Study, a nationally representative longitudinal survey that looks at topics like economic activities, education outcome, family dynamics, relationships, and health.
The cognitive ability module of the test has standardised mathematics and word-recognition questions and was sorted in ascending order of difficulty. The score given was the highest rank of a question that a person was able to answer. This dataset was then compared to the local pollution data.
The researchers were able to show that the scores of the cognitive module of the test fell with increased long-term and transient exposure to air pollution. The decline was more pronounced in the verbal tests than in mathematics.
When the results were plotted based on gender and educational qualification, the researchers saw that men 44 years or older with primary school education were the most impacted. For subsample with more education, men 65 years and above were impacted.
“We speculate that the pollutant damage is most likely accumulating in the white matter of the brain which is mainly associated with the language functioning. The negative impact of three-year accumulative exposure to air pollution for men’s verbal test scores is 49% higher than that for women,” Zhang, who is also a senior research fellow with the Washington-based International Food Policy Research Institute (IFPRI), said.
“This could be because men have a much smaller amount of white matter activated during intelligence tests so their cognitive performance is more affected. Of course, more research is needed to test this out,” Zhang added.
The research estimated that reducing fine particulate matter concentrations to the US Environmental Protection Agency (EPA) standard (50 μg/m3) would increase verbal and math scores by 2.41 and 0.39 points.
Though the research was conducted in China, the researchers suggest that the implications would be true for all developing countries, including India.
The world’s top 20 most polluted cities, according to the World Health Organization’s (WHO) database, are in developing countries. Almost all the cities in low- and middle-income countries with more than 1,00,000 residents fail to meet WHO air quality guidelines.
“The findings should be applicable to India. In fact, the impact probably is greater given that the air pollution is more severe in Delhi than in Beijing and other Chinese cities,” said Zhang.
Doctors from India said the study was a good start but added that more research is required to show that the impact of air pollution on the human brain is definitive.
“The study points a way. However, the researchers have retrospectively analysed the data and tried to fit it into a mathematical model. This can just show a correlation between high pollution levels and lower scores,” Dr Vinay Goyal, professor of neurology at All India Institute of Medical Sciences (AIIMS), said.
“Also, what about the socio-economic parameters? Most likely than not the people living in the most polluted areas are the poorest, they might not fare well on the test, not because of pollution but also because of the missing opportunities,” Dr Goyal, who is also the editor of the journal Annals of Indian Academy of Neurology, added. (Source: The Hindustan Times)


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Air pollution lowers brain function, can lead to lower verbal and maths scores: Study.