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Infectious Diseases

04 October 2020

Coronavirus science | Week in review: Neurological effects, diabetes, and faulty genes

Recap of the latest coronavirus research and science: The silent third wave of Covid-19 might be Parkinson's; evidence on Covid and diabetes; and the role of faulty genes.

LATEST SCIENCE AND RESEARCH

READ | The silent third wave of Covid-19 might be Parkinson's

The neurological effects of Covid-19 have been well documented, but some scientists are raising concerns about its potential influence on the future development of neurological conditions like Parkinson's disease.

This hypothesis was explored in a recent paper published in the Journal of Parkinson's Disease, where researchers theorised that Covid-19's neurological symptoms could be a precursor to diseases like Parkinson's.

For example, the coronavirus symptom of losing one's sense of taste and smell also appears in Parkinson's and Alzheimer's. This symptom is probably underestimated due to a reliance on self-reporting from patients.

It could mark a "third wave" of the pandemic that healthcare systems around the world should prepare for.

Scientists missed the opportunity to study neurological phenomena during the time of the 1918 Spanish Flu pandemic, where patients presented with encephalitis lethargica – a disease that attacks the brain and causes a zombie-like state.

In the 1920s there was a rise in other similar Parkinsonism conditions, which is any condition that causes tremors, impairs speech and limits movement due to the loss of dopamine-containing brain cells. This happened again in the 1940s.

READ | Covid-19 and diabetes: What the evidence says

Diabetes has been reported to be a risk factor for severe Covid-19, the disease caused by SARS-CoV-2. This is because high blood sugar levels can weaken the immune system, making it harder for diabetic people to fight off infections such as Covid-19.

During a Covid-19 special session at the online Annual Meeting of the European Association for the Study of Diabetes (EASD), a new review of the evidence on the devastating impact of Covid-19 on people who have diabetes was presented by Professor Juliana Chan from the Chinese University of Hong Kong and Prince of Wales Hospital, Sha Tin, Hong Kong, China, according to EurekAlert.

"Major risk factors for mortality include advanced age and chronic conditions, notably obesity, diabetes, hypertension, heart and kidney disease as well as social deprivation, minority ethnic groups and those with poor access to care," said Chan, explaining that these common coexisting conditions highlight the complexity of Covid-19.

A recent report (from The Lancet Diabetes & Endocrinology), based on a UK population-based survey of more than 60 million people registered with the primary care system, showed that 0.4% had type 1 diabetes, and 4.6% had type 2 diabetes.

However, the report further highlighted that among the more than 24 000 Covid-19-related deaths, 30% occurred in diabetics.

After the researchers of the paper adjusted for several risk factors, including social deprivation, ethnicity and other chronic conditions, they found that people who had type 1 diabetes had an almost threefold (2.86) risk of death. In those who had type 2 diabetes, they found an almost two times (1.8) higher risk of death due to Covid-19, compared to those who did not have diabetes.

READ | How the coronavirus spreads in a hospital setting

Hospitals understandably have a high rate of coronavirus infections, with increased exposure of healthcare workers. Understanding how Covid-19 might spread in a hospital setting is vital in implementing measures to stop it.

Research presented at the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Conference on Coronavirus Disease this week showed how the virus spreads through a hospital via asymptomatic workers and certain hot spots like toilets and public areas in two presentations.

The first was a meta-analysis of studies in Embase, Pubmed, LILACS, MedxRiv and Google Scholar databases to assess how prevalent the virus is in a hospital, the risk factors for healthcare workers, symptoms and outcomes of severe cases.

It involved 97 studies from across 24 countries with data from over 230 000 healthcare workers. Out of that total, about 10% tested positive for the virus, while 7% had developed antibodies to the disease.

The Swiss researchers found that in 15 of those studies, 40% of healthcare workers that tested positive for Covid-19 were asymptomatic, indicating a high likelihood of silent transmission between colleagues and to patients.

Almost half who tested positive were nurses, followed by physicians at 25% and other workers at 23%. The most common symptoms were loss of taste and smell, fever and muscle pain.

WATCH | Study reveals how fast conversation droplets spread in a building

Feeling safe to chat with your mask off in a restaurant? New research shows how animated conversation can propel droplets through a building – one of the main routes of the new coronavirus.

This is especially true in the case of pre- or asymptomatic spread through close-proximity talking and breathing – without the help of coughing or sneezing. This has already been well-documented, taking place at super spreader events like birthdays, family reunions and weddings.

A team of engineers from Princeton University devised an experiment where they recorded the fluid dynamics of speech, using a laser sheet to measure the velocity of droplets and publishing their findings in PNAS.

"Droplet emission occurs during speech, yet few studies document the flow to provide the transport mechanism. This lack of understanding prevents informed public health guidance for risk reduction and mitigation strategies," the engineers explained to justify their experiment.

While hard sounds like "p" cause droplets to travel up to one metre, they found that a train of sentences creates a cone-shaped, turbulent, jet-like flow that can propel droplets over two metres in 30 seconds.

These exhalations exit through the mouth and nose, where viral load tends to be highest.

READ | Severe Covid-19 in younger people could be due to faulty genes and an autoimmune condition

We now understand that there are risk factors that make some people more susceptible to severe Covid-19 than others. These include being elderly, obese and suffering from diabetes.

But what baffles many people, including experts, is the fact that a number of young and healthy people also suffer severe outcomes or die from Covid-19.

Now, new research from the Rockefeller University has shown that more than 10% of young and healthy people who develop severe Covid-19 have “misguided” antibodies that, instead of attacking only the virus, end up targeting the immune system – leading to severe symptoms.

Another 3.5% of young people with severe Covid-19 carry a specific genetic mutation that may explain their severe reaction.

The new research, published in the journal Science, explains that in both groups of younger patients with severe Covid-19, there is a lack of type I interferon – a set of 17 proteins responsible for protecting the body against viruses.

There are two ways the lack of interferon may occur in these cases. In some cases, the proteins are neutralised by auto-antibodies, while in others, patients lack sufficient levels of interferons because of a faulty gene.

CORONAVIRUS CASES LATEST

SA cases update: 

The latest number of confirmed cases is 679 716.

According to the latest update, 16 938 deaths have been recorded in the country.

There have been 612 763 recoveries.

So far, more than more than 4.25 million tests have been conducted, with 21 804 new tests reported.

Global cases update:

For the latest global data, follow this interactive map from Johns Hopkins University & Medicine.

Early on Sunday morning, positive cases worldwide were almost 34.76 million, while deaths were more than 1.03 million.

The United States had the most cases in the world - more than 7.37 million, as well as the most deaths - more than 209 000.

WHAT'S HAPPENING IN THE REST OF THE WORLD 

Latest news:

HEALTH TIPS (as recommended by the NICD and WHO)

• Maintain physical distancing – stay at least one metre away from somebody who is coughing or sneezing

• Practise frequent hand-washing, especially after direct contact with ill people or their environment

• Avoid touching your eyes, nose and mouth, as your hands touch many surfaces and could potentially transfer the virus

• Practise respiratory hygiene – cover your mouth with your bent elbow or tissue when you cough or sneeze. Remember to dispose the tissue immediately after use.

Image credit: Pixabay