What is a Virus?
Viruses are non-cellular, microscopic infectious agents that can only replicate inside a host cell.
- From a biological perspective, viruses cannot be classified either as living organisms or non-living.
- This is due to the fact that they possess certain defining characteristic features of living organisms and non-living entities.
- In a nutshell, a virus is a non-cellular, infectious entity made up of genetic material and protein that can invade and reproduce only within the living cells of bacteria, plants, and animals.
- They are called non-cellular because they don’t have a cell structure, rather only the genetic material.
- Viruses are the border between living and nonliving organisms.
- They act as living organisms when they are present in a host organism (cell),
- Otherwise, they are nonliving organisms.
- They are crystal-like structures when they are outside, and becomes infecting and lethal when they enter a living cell.
- Viruses are inert outside a host cell, and then they are called virions.
- Some viruses partially contain DNA (DeoxyRibonucleic acid) or RNA (Ribonucleic acid) with single or double strands. It can get into the DNA of the host organism.
- Viruses are classified on the basis of genetic material – ds DNA (polio), dsRNA, ssDNA, ssRNA (orthomyxoviruses).
- Viruses cause diseases among animals and plants. Potato mosaic and tobacco mosaic are the common viral diseases among plants; chickenpox, AIDS, and Ebola are the common viral animal diseases.
- Viroids and prions are the infecting proteins and RNA, they lack cell covers like a virus or any other eukaryotes. They were discovered by T Dienner in 1971 and these are also responsible for diseases among animals. E.g. mad cow disease.
About Corona Virus
- Corona viruses are large family of viruses, which cause illnesses to people and also circulate in animals including camels, cats and bats.
- They cause illness ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome. (SARS)
- 2019-nCoV is a new strain that has not been previously identified in humans.
- Much remains to be understood about the new coronavirus, which was first identified in China earlier this month.
- Not enough is known about 2019-nCoV to draw definitive conclusions about how it is transmitted, clinical features of disease, or the extent to which it has spread. The source also remains unknown.
Why is it called the Wuhan Virus?
- The first cases emerged in Wuhan in central China’s Hubei province.
- On December 31 last year, authorities confirmed that a large number of patients with unexplained pneumonia were admitted in hospitals in the city.
Symptoms of infection
- According to the WHO, common signs include fever, cough, and shortness of breath. Serious infections can lead to pneumonia, kidney failure, and death.
- Although human-to-human transmission has now been confirmed, the WHO says animals are the outbreak’s likely primary source. It is not known yet which animals are responsible.
- To prevent the spread of all respiratory infections, the WHO in general asks people to cover their mouths and noses when coughing or sneezing, and to frequently wash their hands.
- Direct contact with farm or wild animals should be avoided — similar outbreaks in the past, like the Severe Acute Respiratory Syndrome (SARS) emerged from markets where people were in contact with live animals.
What is Herd Immunity?
- Herd immunity is when a large number of people are vaccinated against a disease, lowering the chances of others being infected by it.
- When a sufficient percentage of a population is vaccinated, it slows the spread of disease.
- It is also referred to as community immunity or herd protection.
- The decline of disease incidence is greater than the proportion of individuals immunized because vaccination reduces the spread of an infectious agent by reducing the amount and/or duration of pathogen shedding by vaccines, retarding transmission.
- The approach requires those exposed to the virus to build natural immunity and stop the human-to-human transmission. This will subsequently halt its spread.
- Plasma is the liquid part of the blood. Convalescent plasma, extracted from the blood of patients recovering from an infection, is a source of antibodies against the infection.
- The therapy involves using their plasma to help others recover. For Covid-19, this has been one of the treatment options.
- The donor would have to be a documented case of Covid-19 and healthy for 28 days since the last symptoms.
Hydroxychloroquine for Corona Virus
Hydroxychloroquine is now a schedule H1 drug and can be sold on prescription only.
What are Schedule H1 drugs?
- The sale of the Hydroxychloroquine drug from now on should be in accordance with the conditions for sale of drugs specified in Schedule H1 to the Drugs and Cosmetics Rules, 1945.
- In exercise of the powers conferred by Section 26B of the Drugs and Cosmetics Act, 1940 (23 of 1940), the Central Government can direct that sale by retail of any drug.
- Hydroxychloroquine is used to prevent or treat malaria infections caused by mosquito bites.
- It does not work against certain types of malaria (chloroquine-resistant).