Monday, January 21st
I'm a virus (病毒) for the common cold. It has been a long time since I infected (感染) humans last time. Today I tried to infect a boy in a primary school all day.
His name is Sam. I waited on his desktop, and when he touched the desk I jumped on his finger. Unluckily, Sam didn't touch his eyes, mouth or nose. Then, right after class, he washed his hands. Now I'm full of soap and sitting in a sink!
Tuesday, January 22nd
This morning I jumped into the nose of Sam's best friend, Bill. Unluckily, the mucus (粘液) in his nose caught me. I thought it was over for me, when suddenly Bill sneezed while he was talking to Sam.
I knew that would send me right into Sam's face! However, Sam quickly gave Bill a tissue, and Bill sneezed into that instead! Infecting people is harder than I imagined.
Wednesday, January 23rd
I'm feeling very unhappy today. Some scientists caught my friend Harry and put him under a microscope. Harry is a flu virus and he's a dangerous little guy. Besides, Sam at all his vegetables today. He's exercising, ad he's getting eight hours of sleep every night. His body is too strong for me!
Thursday, January 24th
I tried to infect Sam again today, but he washed his hands five times and never touched his face! He also gave tissues to every student in his class who was sneezing. It's impossible to give him a cold! So I have to give up and I'm moving to another school.
Diabetes is caused by a group of metabolic disorders in which there are high blood sugar levels over a long period of time. There are three main types of diabetes:
l Type 1 Diabetes results from the body not having enough insulin.
l Type 2 Diabetes mainly happens to those who do not have enough physical exercise, eat too much unhealthy food and get too heavy.
l Gestational Diabetes is the third main form. It appears when a woman is having a baby. She will probably get well again after the birth of the baby.
Diabetes can bring serious problems. People with diabetes, especially the Type 1, will easily get thirsty and hungry, and quickly lose weight. If it is not treated, it will develop rapidly (weeks or months), and cause many long-term complications. All the complications relate to damage to blood vessels. For example, damage to the eyes. It is caused by damage to the blood vessels in the eyes, and results in gradual vision loss and blindness. The complications will greatly increase the risk of diabetes, by which about 75% of the deaths are caused.
According to a report from the WHO (World Health Organization) in 2015, about 415 million people have diabetes worldwide, which means 8. 3% of the adults in the world have diabetes. Of all the cases, 85% to 90% are Type 2 Diabetes. That is to say, most cases of diabetes result from the unhealthy life style. Diabetes doubles a person's risk of early death. From 2012 to 2015, about 1.5 to 5 million deaths each year resulted from this disease. The global economic cost of diabetes in 2014 was around 612 billion USD.
A healthy life style can help prevent diabetes. Doing a lot of physical activities and having a healthy diet will help have normal body weight. Higher levels of physical activity (more than 90 minutes per day) can reduce the risk of diabetes by 28 %. Healthy diet includes foods rich in whole grains and fiber, foods with good fats from nuts, vegetable oils and fish, little sugar, and less red meat.
Most viruses can be found and killed by our immune system as soon as they enter our bodies. However, some viruses, for example, the coronavirus, are sneaky. They are difficult to recognize and find. These viruses can cause deadly diseases, like COVID-19. Human-to-human transmission can easily occur, and pandemic will therefore break out. Vaccination is by now a simple, safe and effective way to protect us from the diseases.
▲ Vaccines are something that "looks" exactly the same as the viruses, mainly made from the viruses that are weakened or killed. They will not make us really ill. They only stimulate and activate * our immune system to work, telling it something harmful is coming in. The immune system will know what the "viruses" look like, and send B cells(lymphocytes) or antibodies to find and kill them. Meanwhile B cells will remember them for the next kill. A vaccine may also give us passive immunity by providing B cells taken from an animal or a human to play the same role.
Scientists have developed more than 180 vaccines to fight against COVID-19. The technical approaches of these vaccines can be a little different, but their aims are the same.
Take the inactivated vaccine as an example. In an inactivated vaccine, the coronaviruses are already killed or made into the ones unable to produce more new viruses. When the immune system "sees" them, it will try to kill them. The question is: without enough these viruses• how can B cells remember them? That's why we need to take the vaccine more than one time. Though this vaccine is safe, it might not be as effective as it is expected to be.
The live-attenuated vaccine is different. In this vaccine, the viruses are weakened, but they are alive. They can produce enough new viruses to train the immune system to kill and remember them, so people only need to take the vaccine once. The live-attenuated vaccine is considered the most effective, but there is a worry: what might happen once these viruses wake up?
Therefore, although vaccination is by now one of the best ways to protect us from COVID-19, it can be better.
