Viruses are the smallest of all the microbes; small particles of genetic material (either DNA or RNA) that are surrounded by a protein coat. Viruses may survive boiling, freezing, and chemical attack, and can suddenly be reactivated after long periods of dormancy. They are incapable of reproducing on their own. They must have living cells, or host cells, in order to replicate themselves, as they have no cellular machinery for obtaining energy or raw materials for reproduction. A virus invades a host cell and takes over the cell's machinery, which causes the cell to die or function abnormally. Viruses are classified by their shape size, and the groups of diseases they cause.
There are thousands of different types of viruses. When most people hear the word "virus," they think of disease-causing (pathogenic) viruses such as the common cold, influenza, chickenpox, human immunodeficiency virus (HIV), and SARS-Cov-2, a respiratory coronavirus that causes Covid-19 infection; however, viruses can also affect the reproductive, gastrointestinal, and central nervous body systems. Research reveals that viruses are implicated in many cancers as well - as in the following:
Epstein-Barr virus (EBV) for nasopharyngeal cancer, Burkitt lymphoma, Hodgkin's lymphoma, and stomach cancer
Hepatitis B and hepatitis C for liver cancer
Human immunodeficiency virus (HIV) for Kaposi sarcoma, invasive cervical cancer, lymphomas, and other cancers
Human T-lymphotropic virus-1 (HTLV-1) for T-cell leukemia/lymphoma (ATL)
Human papilloma virus (HPV) for cervical cancer
Merkel cell polyomavirus (MCV) for a rare skin cancer called Merkel cell carcinoma
A viral infection is a proliferation of a harmful virus inside your body. Viruses infect a host by introducing their genetic material into the cells, making copies of itself, and bursting the host cell (killing it) to set the newly-formed virus particles free. In other cases, virus particles "bud" off the host cell over a period of time before killing the host cell. Either way, new virus particles are then free to infect other cells. Symptoms of the viral illness occur as a result of cell damage, tissue destruction, and the associated immune response. Certain viruses - like the ones that cause chickenpox and cold sores - may be inactive or “latent” after the initial infection, until a trigger like stress, sunlight, or something else, may reactivate the virus and lead to new symptoms. The virus makes more copies of itself, releases new virus particles, and kills more host cells.
Contagiousness refers to the ability of a virus to be transmitted from one person (or host) to another. Viral infections are contagious for varying periods of time depending on the virus. An incubation period refers to the time between exposure to a virus (or other pathogen) and the emergence of symptoms. The contagious period of a virus is not necessarily the same as the incubation period.
Most people get infected with human strains of coronaviruses at some point in their lives. These respiratory illnesses affect the lungs, nose, and throat, and usually last for a short amount of time, manifesting themselves through common symptoms of fever, cough, headache, runny nose, and sore throat. These viruses are most commonly spread by inhaling droplets containing virus particles. The more serious types of coronavirus, such as MERS, SARS, and COVID-19 can cause bronchitis or pneumonia in individuals with weakened immune systems (such as those with heart and lung disease, infants, and seniors).
Viruses can spread through touch, saliva, air, sexual contact, contaminated needles, or can be transmitted by Insects, like ticks and mosquitoes, which act as "vectors," transmitting a virus from one host to another. Contaminated food and water are other potential sources of viral infection.
Frequent hand-washing, covering the nose and mouth when coughing or sneezing, and avoiding contact with infected individuals can all reduce the spread of respiratory infections. Disinfecting hard surfaces and not touching the eyes, nose, and mouth can help reduce transmission as well. As we all experienced during the Covid-19 pandemic, wearing a mask and social distancing may decrease chances of getting such viral infections as the flu and COVID-19.
Viruses are unaffected by antibiotics, but can sometimes be treated with antiviral drugs. Some immunizations may prevent viral infections. Phytochemicals (found in plant foods) show strong anti-viral properties in the lab. Thousands of these compounds that protect plants from pathogens may also protect the human body when consumed. These plant compounds reduce free radical damage and inflammation; and, strengthen our immune system which provides the body with a fighting chance against viral attacks. There are contemporary studies on the antiviral properties in phytochemicals to treat viruses such as Covid-19, in articles such as, "A molecular modeling approach to identify effective antiviral phytochemicals against the main protease of SARS-CoV-2." Keep updated on results in the Journal of Biomolecular Structure and Dynamics (Volume 39, 2021, Issue 9). "Edible plants present in Indian biodiversity being used as food or nutraceutical showing anti-retroviral activity," is another great study to review. We will look at these plant foods and their anti-viral properties over the next few weeks. We will begin with, "The Gift of Garlic," in next week's Friday blog!
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