Overview of Viruses Flashcards
What is a virus?
-Microscopic infectious agents that can infect anything living (plants, animals, bacteria)
-Made up of DNA or RNA and this genetic material is encased in a protein shell called capsid
-Some viruses have an outer envelope made up of lipids
Virus Significance
-responsible for wide range of disease in humans
-again cause disease in any living thing like plants, humans and animals
-They cause economic problems like plant viruses that damage crops
-Play critical role in scientific discoveries like gene therapy and making new vaccines
Examples of important viruses
1) The influenza virus causes seasonal flu outbreaks which can be mild or severe. Is very contagious and spreads fast by respiratory droplets
2)HIV, or human imminodefiency virus, is a virus which attacks the immune system and leads to the development of AIDS(acquired immunodefiency syndrome) HIV transmitted by blood, semen, vaginal fluids or breast milk
3)Severe Acute Respiratory Syndrome Coronavirus or SARS COV2 is the one responsible for COVID 19 and caused significant morbidity and mortality worldwide. Very contagious and spready like influenza (droplets).
4)Human papillomavirus or HPV can cause several cancers like cervical cancer and transmitted by sexual contact
5)Tobacco mosaic virus is one that infects tobacco plants and causes significant money losses in that industry. Well studied and modeled virus that contributed greatly to understanding of viral replication and assembly
First Virus
1898, Beijerinck was the scientist first used the word virus. This was to identify the mosaic disease of tobacco. 5000 viruses were identified as infecting plants, animals, people, insects and bacteria.
Why study virus?
-virus are very deadly, top 10 deadliest shown below
1)Number most deadly is HIV/AIDS which has caused 25 million deaths from 1981. AIDS is mix of infections and complications as a result of progressive damage to body immune system from HIV. Aids is now considered a pandemic
2)Influenza has caused 36,000 deaths yearly which is also known as the flu caused by influenza virus. Transmission is airborne and physical contact. SPANISH FLU- from 1918 and 1919, 100 million death caused by it and was categorized as a category 5 flu pandemic and was caused by flu virus strain A with subtype HINI
3) The bubonic plague killed 250 million deaths and caused by fleas and rodents infected with Xenopsylla cheopsis. Humans were infected after being bitten by rodent.
4)Malaria caused 2.7 deaths annually and is an infectious disease that is vector born. The causative agent is the protozoan parasites. Common disease in tropics and subtropics regions
5)Ebola resulted in 160,000 deaths from 2000 to now. It is zoonotic disease since it affects apes and humans
6)Cholera is a diarrheal illness caused by infection of intestine with toxigenic bacterium Vivrio chloerae serogroup OI or O139. There have been 2.9 million cases and 95,000 deaths yearly.
7) Smallpox made a population drop from 12 million to 200,000k. Smallpox is highly contagious viral disease that has two variants. V major has 35% mortality rate and V minor has 1% mortality rate.
8) Polio has resulted in 10k deaths frrom 1916 to today. Polio or infantile paralysis is viral disease that is transmitted through fecal oral course
9)Tuberculosis has caused 75 million deaths and is life threatening if not treated in elderly or infants or compromised indivduals (immune problems). Resulted in 100 million deaths in 20th century
10)COVID, starting 2020 was declared a pandemic and there have been 100 million cases and 2.6 death related to covid
Fun fact
6/10 of the deadliest diseases are caused by virus
Why study viruses?
1)To prevent disease-responsible for many diseases in all forms of life. Study helps to discover how they work/spread and then we can work to prevent them and treat the diseases they cause
2)Scientific discoveries-Viruses play major role in new discoveries like vaccines, gene therapy and other medical treatments. The benefit of human health and wellbeing
3)Environmental impact-Viruses have big impact on environment since they affect health of animals and plants. Studying leads to mitigating their affect on those species to lessen affect on ecosystem
4)Economic impact-Viruses have significant economic impact(like disease on crops) and we can study to control the spread of these viruses and overall reduce the impact on economy
5)Evolutionary biology-Viruses are the most ancient and diverse forms of life, by studying them we can learn more of evolution of life and genetic mechanisms that underlie it
