known as SARS-CoV-2 that caused a pandemic of coronavirus disease (COVID-19) which causes respiratory and intestinal infections in humans. Coronaviruses are enveloped, positive-sense single-stranded RNA viruses. They are members of the subfamily “Coronavirinae” (family; Coronaviridae, order; Nidovirales). Coronavirus contains four genera: 1. alpha-coronavirus (e.g., 229E, NL63) : infect mammals 2. beta-coronavirus (e.g., SARS-CoV, SARS-CoV-2, HKU1, OC43, MERS-CoV) : infect mammals 3. gamma-coronavirus : infect birds 4. delta-coronavirus : infect birds . Human coronaviruses primarily cause respiratory infections. A number of strains of coronaviruses are recognized, most of which are responsible for the common cold.
that rapidly spread in the region, then to Hong Kong, Vietnam, and Singapore. Focal outbreaks were also reported in other countries by travelers from the endemic region who became ill when they returned home. The virus was named SARS-CoV. Two facts about this virus are critical: person-to-person spread occurred readily, including in the health care workers exposed to the patients, and the disease was responsible for a high mortality rate, particularly for patients with underlying pulmonary disease (i.e., 50% mortality) and in the elderly. MERS-CoV In 2012 a new coronavirus infection erupted in the Middle East, again associated with a high mortality rate. This strain, MERS-CoV, has spread from the initial focus in the Kingdom of Saudi Arabia through the Middle East and to other countries via travelers. In contrast with the SARS-CoV strain, this coronavirus is only intermittently spread person-to-person; however, coronaviruses have a high mutation rate so this can change rapidly. In addition, the strain continues to circulate in the Middle East. It is interesting that both the SARS-CoV and MERS-CoV strains are related to bat coronavirus strains. The SARS-CoV strain was isolated in bats, and there is epidemiologic evidence to implicate bats in the MERS-CoV.
and colleagues described a previously healthy patient who was transferred to his hospital after a 9-day history of persistent fevers, myalgias, and headache. The patient presented with a fever of 39.4°C, chills, a dry cough, shortness of breath, and diarrhea. Chest x-ray showed inflammation in the right upper lung fields. White blood cells and chemistries were normal. The patient failed to respond to antibiotic treatment. On day 3, he developed a deep cough and dyspnea along with diffuse pulmonary inflammation. The diagnosis of SARS was made in view of his severe hypoxemia with PaO2 of 60 mmHg and PaO2 /FiO2 of 150 mmHg, and a clinical picture consistent with other hospitalized patients with SARS. The patient was transferred to the intensive care unit and placed on ventilatory support, but continued to deteriorate into multiorgan dysfunction syndrome involving the kidney, liver, and heart. The medical staff initiated molecular adsorbent recirculating system therapy (extracorporeal liver support utilizing albumin dialysis for 8 hours) and after 4 consecutive days of therapy, clinical improvement was noted. After 13 days, ventilatory support was withdrawn and the patient continued to improve. The patient was discharged after 44 days of hospitalization. This case illustrates the severe infection caused by SARS-CoV .
to 14 days after exposure and can include: Fever Cough Shortness of breath Persistent pain or pressure in the chest New confusion or inability to arouse Bluish lips or face  Tiredness Aches Runny nose Sore throat  Loss of appetite Diarrhea Vomiting Abdominal pain .
has contracted a virus but isn’t manifesting any of the symptoms it causes. In case of COVID-19, the SARS- CoV-2 virus infects the cells which are involved in oxygen circulation, also known as alveolar cells. It can affect the ability of a person to take in oxygen that's why one of the most-common symptoms of the current coronavirus is shortness of breath. Asymptomatic and mildly symptomatic transmission is a major factor in transmission for COVID-19. In asymptomatic carrier the virus has infected the cells, but: The immune system is taking too long to react (and symptoms will show up later). The immune system kicked in early enough in the infection's course to not manifest symptoms. The infection is very mild and it's not enough to engage a strong immune response .
organism to invading biotic or abiotic pathogens and their harmful effects that prevents the development of infection and maintains organism’s integrity by counteracing, neutralizing, and clearing pathogens . Immune system Collection of cells, tissues and molecules that mediate resistance to infections and eradicate established infections is called immune system. Immune response The coordinated reaction of cells and molecules to infectious microbes is the immune response.
It is a host defense mechanism that provides initial protection against infections. It is a first-line of defense against non- self pathogens. This type of immunity is always present in healthy individuals, prepared to block the entry of microbes and to rapidly eliminate microbes that do succeed in entering host tissues. It is a person’s natural immunity which generates non-specific but a rapid response. It is less potent and is unable to develop memory cells. Native or natural immunity. It develops more slowly and mediates the later, even more effective, defense against infections. It is a second-line of defense. It is stimulated by microbes that invade tissues, that is, it adapts to the presence of microbial invaders. It is an acquired immunity which generates specific but delayed response. It is highly potent and has capability to develop memory cells. Specific or acquired immunity
that help to defend the host against foreign invasion, when a host is challenged by antigen i.e foreign material (bacteria, virus, toxins, etc.). Antibodies are medically and experimentally important immune system proteins. By binding to foreign molecules with high specificity and affinity, they act as flags that guide the immune response. Vitamins Vitamins support body’s natural defence mechanism by enhancing the immune response towards pathogens. They help the body in fighting against variety of illness and protect the body from damage to cells. Types: A, B, C, D, E, K Vitamin A, B, C, D, E provides strength to immune cells during pathogen attack/ inhalation of toxic material from air or that may be present in food. Drugs, tea, caffeine, smoking, alcohol, dietary fibers etc affect the vitamins. Vitamins are essential for antibody production.
a novel coronavirus (SARS-CoV-2), their biology and therapeutic options. Journal of Clinical Microbiology. 2020: 1-23. 2. Patrick R. Murray. Basic Medical Microbiology. ELSEVIER. 3. https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html 4. https://www.mayoclinic.org/diseases-conditions/coronavirus/symptoms-causes/syc- 20479963 5. https://www.webmd.com/lung/news/20200319/about-half-of-covid-cases-show- digestive-signs 6. https://www.inverse.com/mind-body/coronavirus-how-asymptomatic-carriers-spread- virus-like-covid-19 7. https://www.sciencedirect.com/topics/immunology-and-microbiology/immunity 8. Aslam MF et al. Vitamins: Key role players in boosting up immune response- a mini review. Vitamins & Minerals. 2017; 6(1): 1-8. 9. https://www.healthline.com/health/food-nutrition/foods-that-boost-the-immune-system