[Biology Class Notes] on Common Cold Pdf

The common cold is a type of viral infection that usually affects the upper respiratory tract of the person infected. The common cold will be affecting the nose primarily, but in the process will also affect the sinuses, larynx, and the throat. The common cold and influenza are both respiratory illnesses, but the two conditions are caused by different viruses. The patience that is affected by cold has symptoms that are very similar to persons who are suffering from influenza, as the influenza symptoms which are seemingly similar but are much more severe. While the cold symptoms can last for a few days, influenza symptoms can make you feel sick for a few days to weeks.

Influenza is an infection that can lead to serious health conditions such as pneumonia and sometimes can even cause hospitalization of the infected person. The common cold is the most frequently occurring infectious disease in the world, affecting humans. An average adult is affected 2 to 3 times a year, while an average child may get 6 to 8 times a year depending on their age and the exposure. The common cold is prevalent during the fall, winter, and spring. Over 200 cold viruses exist, but the most common that is thought to be responsible for at least 50 % of cold is the Rhinovirus. Other viruses that can lead to cold are coronavirus, adenovirus, and respiratory syncytial virus. 

The virus enters the body through the mouth, eyes, or nose and is spread by hand to hand contact. This usually happens when an infected person blows and touches their nose and then touches another person or an object. A healthy individual who is exposed to this infected secretion either by direct contact or by touching the contaminated object becomes infected. Often after their contaminated hand touches their own eyes, nose, or mouth. The virus can also spread through droplets in the air after infected individuals sneeze, cough, or talk. Symptoms usually occur after 1 to 3 days of being exposed to the cold virus. The signs and symptoms may vary from person to person and include sore throat, cough, sneezing, running or stuffy nose, loss of smell or taste, low-grade fever. Chest discomfort, difficulty in breathing, fatigue or tiredness, body aches, chills, headaches. Mucus draining into the back of your throat from the nose, hoarse voice. A doctor can diagnose your common cold based on your signs and symptoms and findings during their physical exams. If there are concerns about another underlying medical condition such as your bacterial infection, your doctor may order an x-ray or other tests. No cure exists for the common cold; the common cold will resolve with time on its own and expectant management. Home remedies and medical treatment are directed at relieving the symptoms associated with the common cold. Home remedies for the common cold for older children and adults may include getting rest, taking a lot of fluids. 

Using saline nasal drops to help relieve nasal congestion, warm salt water gargles may be beneficial to people with a sore throat. In infants and small children, home remedies may include getting rest, taking plenty of fluids, saline nasal drops and bulb suctioning may be used in clearing mucus from the nasal passage. This procedure involves applying a saline drop and gently suctioning the nostril with a bulb syringe inserted about ½  or ¼ inch. Medical treatment may include pain relievers for fever, sore throat, and headache. Acetaminophen (Tylenol and others) and ibuprofen (Advil) may help with such symptoms. Adults can use a decongestant nasal spray, but children younger than 6 are not recommended to use the decongestant nasal spray.

 

Common Cold Develops

A cold is a viral illness that will usually last for about one week. A cold virus such as the rhinovirus and coronavirus is taken into the body when you breathe them in from the air or when you touch surfaces that have the virus on them and then you touch your mouth, nose, or eyes. You can easily catch a cold virus from either close or direct contact with someone who is infected with the virus. Let us take an example. Let us consider kissing a person who has been infected by the virus. You can get infected by this as your airways, eyes, mouth, and nose are all connected to each other. Cold viruses can pass through these tubes and cavities to cause the symptoms of a cold. It has been observed that the old viruses grow in soft, warm surfaces such as your sinuses, nose, airways, or the throat where they can cause the infection. 

If the person has been infected with the cold virus it will trigger the immune system which in turn produces antibodies that attach itself to the virus and thereby destroy it. Your body also makes mucus which traps the virus. It is known that we tend to swallow the viruses so that they can be destroyed by the acid which is in your stomach or they are usually removed from the body when we blow your nose. Excess mucus production causes the symptoms of blockage of nose, sneezing, and coughing. You may also have a headache which may be caused by the pressure in the sinuses blocked with mucus. Your body gradually fights the infection so you feel better after about a week.     

Differentiate the Flu from a Cold

It usually causes a tingle in your throat or simply a single sneeze which is followed by a headache, nagging cough, running nose, and drowsiness now we can say that you have caught a virus. The main question here arises is to know if it is the constantly mutating influenza virus known as the flu or is it one of the 200 strains of the common cold because there is a difference. As in influenza, it tends to be an illness that has a sudden onset and more likely to cause a high fever. Fits and pains, running nose in other words if you are hit by the flu you will know. The influenza virus is responsible for one of the deadliest pandemics in history including the Spanish flu in 1918 which spread across the US, Europe, and Asia affecting the third of the global population, killing up to 50 million people worldwide, 8 million in Spain alone. In fact, more soldiers in world war 1 died from the flu than the actual battle. 

But the pandemic flu is a completely different beast, for now, let us focus on the seasonal flu and the common cold. While both of these attack your respiratory tract the cold tends to stay up in the nose and sinus area. Whereas the flu can enter deep into the lungs and cause complications especially for young children, people above 65, pregnant women, and individuals with long term medical conditions and weaker immune systems. Cold symptoms are much milder, more common hence common cold. The most common of common colds is the Rhinovirus, on average adults, get 2 to 3 colds a year. It is one of the leading causes of miss days of work and costs close to 25 billion dollars annually in lost productivity in the US. 

Unlike that we see in the flu which seems to have a specific season that comes between October and May usually what we see in the northern hemisphere. The cold can hit any time of the year but is more common in the winter months. But contrary to popular belief you can actually catch a cold in the cold, you are more likely to catch it in a closed space where viruses are constantly circulating. The reason we get sick more in the winter is simply that we herd together indoors, the windows are shut and we are more likely to breathe the same air as someone who already has the virus. Whether it be a cold or the flu the way the virus enters your body is the same. Let us take a scenario, for example, John Doe is sitting in the bus while battling the virus infection, as he sneezes before he has time to cover his mouth, a projectile containing nearly 40 thousa
nd tiny viruses filled droplets are expelled into the air. Those particles can fly up to 2 meters, making anyone nearby a target. The pathogen enters the lining of the respiratory tract of the person nearby. As it enters it uses a protein spike like a key to enter a cell, hijacks the nucleus, and begins replicating even more viruses. Symptoms usually start within 1 to 3 days after being exposed to the virus. The first 3 days of coughing and fatigue are when you are the most contagious to others. By now the person will have spread the virus to the partner at home and they both have taken the viruses to work contaminating different surfaces. Which then spread to their co-workers and that is one of the fastest ways we spread germs. It can survive on surfaces for at least up to a day and on steam for an hour. So you might shake hands with someone or touch a doorknob and afterward if you touch your eyes and that’s one way of infecting yourself. 

On average humans touch their faces 3 to 5 times every minute without even realizing it. Most of the time your body is strong enough to fight off infection pretty quickly. We have antibodies that are created that will neutralize the virus in the nasal passages and when that happens eventually after a few days the virus becomes inactivated, neutralized, and then the body can heal. Generally, cold clear up within a week to 10 days but the post-viral nagging cough can linger for weeks till it eventually resolves on its own. In the meantime, another cold virus can be lurking around the corner. Influenza can last up to 3 weeks, the virus spreads rapidly causing your body to respond more aggressively. One of the biggest differences between the cold and the flu is that flu usually comes with a fever and symptoms like that have less to do with the actual virus and more to do with the immune response. 

Over the counter medication like acetaminophen and ibuprofen can help control those symptoms. Antibiotics, on the other hand, treat a bacterial infection like bacterial pneumonia and strep throat. It will not help you when you have the flu or cold and will, in fact, do more harm than good. So it is better to see how we can protect ourselves from getting sick, as our immune system’s memory will in part help you with that. Every time a virus is destroyed the B and T cells remember that particular strain so that it can react faster than time and that is similar to how the flu vaccine works. An inactive virus is injected into your system, just enough to trigger cells into action. Health officials say it is a no brainer defense against the flu. So everyone and the general public get it more than the old and the younger is protected. So you are not only protecting yourself you are protecting everyone else. And although not 100 % perfect it still reduces the severity of your symptoms if you do end up getting sick.