BioQuakes

AP Biology class blog for discussing current research in Biology

Author: chellularrespiration

To Smell or Not to Smell?: The Dangers of Covid-19 on your Senses

Out of all the symptoms caused by Covid-19, one of the most bizarre was the complete loss of taste and smell. The loss of taste and smell, more formally known as anosmia and ageusia, is now a very common symptom of Covid-19. Over 80% of people who catch the virus experience it, and it has become one of the most effective ways to diagnose the virus. However, the loss of taste and smell is different for Covid-19 than a regular cold or flu. For Covid-19 loss of taste and smell occurs regardless of a stuffy nose and it can last from 8 days to a whole month. In worse case scenarios those senses don’t come back at all.  Although this is a widely known symptom of Covid-19, have you stopped and wondered why this occurs? 

At first there was a lot of confusion as to why the virus affected our taste and smell. Some scientists thought signs of anosmia meant Covid-19 had entered the brain through the nose. This then damages the olfactory sensory neurons (sensory neurons in the nose) causing lasting damage to the brain. However, with more research and data this fortunately doesn’t seem to be the case. Experts at the Harvard Medical School have been conducting research on this topic and have come up with a possible reason why people have been experiencing anosmia.  To understand how the virus affects people, you first need to know how the virus enters the body. The virus enters the body through a process called receptor-mediated endocytosis. The virus enters the body through the nose and mouth then binds to a certain receptor called the ACE2 receptor protein found in many parts of the body, such as the lungs, liver and kidney. After binding to the receptor the virus enters the cell and releases its own genetic material that gets copied to produce more of it as well as more viruses to spread to the whole body. The researchers at the Harvard Medical School have found that olfactory sensory neurons don’t contain the ACE2 receptor protein, so there isn’t a way that the virus could enter through those cells. Instead they believe the virus affects nonneuronal cells that support the olfactory sensory neurons, such as basal cells and sustentacular cells found in the olfactory epithelium. The virus affecting these cells is what might be causing the loss of smell due to the sensory neurons not being able to function properly without it’s normal support.  There is a lot less known about why the loss there is a loss of taste as well, since taste receptor cells also don’t contain the ACE2 receptor protein. There is still a lot of speculation and a lot more research needed to be done.  However this is good progress and some insight as to how this virus is affecting the senses. 

As stated before most Covid-19 cases people get their sense of taste and smell back, but what happens if your fully recovered and your senses still haven’t returned? In one severe case a teen named Kenny Mayfield caught the virus and has yet to get his senses back. In March, when little was known about the virus, Kenny had been suffering through Covid-19, but wasn’t sure due to lack of testing and knowledge available during that time. After several months when he tested positive for antibodies he was certain that was the case. Although he was no longer suffering from the virus itself, he still had to face the consequences of it, his sense of smell had not returned. Now months later he is still trying to regain his sense of smell. He practices scent retraining to get back his senses, but the process could take 6 months to a year for it to get back to normal. He is able to taste, but without his scent it has become less enjoyable to him, causing him to lose his appetite and lose weight. There have been several other cases just like this one. A man named Eian Kantor has gone 7 month without his senses and is desperately trying to get them back to no avail. Another woman named Freya Sawbridge has begun to regain her sense of taste and smell, but claims everything is warped and unpleasant. Not only with food, these loss of senses can be incredibly dangerous if you can’t smell a gas leak or a fire.  Covid-19 can have a serious effect on your sense of taste and smell and should be taken much more seriously.

The most important thing you can take from this article is awareness. Although it is known that you lose your sense of taste and smell due to Covid- 19, I picked this specific topic because I’ve been very curious about why and how this occurs. I wanted to know more information on it.  Many people shrug off the symptom of loss and taste and smell, because they feel guaranteed that they will get it back. However, like these cases described, it is not always a definite guarantee things will go back to normal. You could end up never getting your senses back or have them return very altered. That is why it is essential to stay safe and keep yourself and others protected. Don’t take the risk, because you could be the one person to experience long term damage that could change your life forever. 

 

Can Your Pet Sense the Next Earthquake?

It has been rumored for centuries that animals may be a key in sensing impending earthquakes. The first account is from ancient Greece when historians claimed “rats, snakes, weasels, and centipedes deserted the city and headed for safety several days before a devastating earthquake”. This observation and many more of its kind have been made all over the world about animal behavior patterns prior to earthquakes, but there was never an in depth research study done to prove if this was a concrete sign of an earthquake or merely coincidence. Until recently, where more scientific studies are being done to try and prove if this is a reliable method to use when predicting earthquakes. 

One scientific investigation into this behavior occurred in Japan in 2011 after they were hit with a massive earthquake damaging and killing many. It was formally named the Tohoku Earthquake. Before this earthquake occurred they surveyed some pet owners, more specifically dogs and cats, to track their animals’ behavior.  They also asked to track the dairy milk production from cows before the earthquake as well. The results of this study were interesting. After they collected their information they found that the pet owners recorded their animals having weird behavior one day before the earthquake, while the cows decreased their milk production about one week before the earthquake. About 18.6% of dogs had usual behavior, that includes sticking close to their owner more frequently. Compared to dogs, cats were reported having only 16.6% unusual animal behavior, which included “hiding”and “escaping”. Although these behaviors could be written off as normal for dogs and cats, the observations made on the milk production were a bit more compelling. Preceding the earthquake there was a milk production, “decrease from four to six days before the Tohoku EQ in the facility closest from the epicenter (340 km)”. They also reported that the closer to the epicenter they were,  the higher the chance of abnormal behavior occurring. However, though this study had some conclusive evidence, it’s not enough to prove that animals’ behavior can predict anything. 

A more recent study in Italy, led by researchers at the Max Planck Institute of Animal Behavior and the University of Konstanz, may lead to even more evidence of animal behaviors linking to seismic events. Wikelski, the director of the Max Planck Institute of Animal Behavior,  along with his team, set up an experiment to study animal behaviors for about four months in total in 2016 and 2017. In this study they traced farm animals, specifically six cows, five sheep and two dogs. They used different instruments to “record accelerated movements—up to 48 each second—in any direction”. After the four months a total of 18,000 tremors happened, and one with a magnitude of 6.6. The results were a drastic increase in activity, hours before the earthquake occurred. According to Wikelski all their behavior was connected in some way. He says, “It’s sort of a system of mutual influence. Initially, the cows kind of freeze in place—until the dogs go crazy. And then the cows actually go even crazier. And then that amplifies the sheep’s behavior, and so on.” Like the previous study done in Japan, they also reported in this study that animal behavior was increasing abnormal closer to the epicenter, unlike the animals that were farther away. They predict this occurs because the shifting tectonic plates “causes the rocks to release minerals that expel ions into the air”. Though a valid hypothesis, there have been some criticisms of this theory. Wendy Bohon, a geologist from the Incorporated Research Institutions for Seismology says geologists all over have been attempting to find signals that come before earthquakes. She says in order for this to be a trustworthy experiment their findings need to have definitely been stimulated from the tremors and not any other stimuli that animals are usually attracted to. Another geologist, Heiko Woith, said they needed to have a longer timeframe to get more concrete evidence. Although there were some flaws in their study, this is not the end of the researchers’ search for more evidence of this research. They plan to create new studies in Italy as well as Chile and Russia to prove that using animal behavior is a reliable source of information in guessing earthquakes. 

I chose this article because it involved a topic I’ve always been curious about and that is the sensing capabilities of animals. I have always heard about different animals and how much higher their sensing capabilities are compared to humans, which made me wonder when I saw the article if this would prove this to be true, even for something as big as an earthquake that often occurs far from the surface of the earth. I also thought that it would be interesting to see how these animals are able to sense these earthquake tremors. The article gave some insight to why this could occur, which has to do with ions potentially being expelled from the rocks. Ions are atoms or molecules that have a positive or negative charge, depending on the proton to electron ratio. When earthquakes occur they give off a magnetic field, which is a result of moving electrical charges, like ions.  Animals could be able to sense this because of a phenomenon called magnetoreception. Magnetoception is “a sense which allows an organism to detect a magnetic field to perceive direction, altitude or location“. There are three types of methods used to explain Magnetoreception: electromagnetic induction, chemical magnetoreception and biogenic magnetite. These animals might be able to sense this on a molecular level. Although it’s not as simple of a theory as this, if this were proven to be true that would be an amazing scientific feat. There is still more research to be done,  but I think it is true that animals have a level of sense high enough to predict an oncoming earthquakes. However the real question is do you think animals are the key in predicting future earthquakes?

 

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