Lecture 1 Flashcards
Impact of smallpox on society
-Pharoah Ramses V died of it in 1157 B.C
-First case in China 2000 years ago
-Hernan Cortez killing 3.5 million Aztecs in 2 years
-Killed 5 reigning European monarchs in the 18th century
Benefit of agar to virology research
Aided in the experimentation of microbes allowing a better understanding of pathogenesis
HIV reports 2023
-39 million people living with HIV (2/3 in the African region)
-630,000 people died and 1.3 million acquired in 2022
-D.C has highest rate in the nation (1.8%)
John Snow
Father epidemiology, pioneered study on cholera outbreak in 1854 England
1850’s Miasma Hypothesis
“Poisonous air” must be responsible for contagious disease
Germ Theory (1880)
Proposed that microorganisms are the cause of some diseases
Koch’s Postulate
-Agent must be present in every case of disease, but not in healthy animals
-Agent must be isolated from a diseased organism & grown in pure culture
-Disease must be reproduced when a pure culture of the agent is inoculated into a healthy susceptible host
-Same agent must be recovered once again from the experimentally infected host
1886 Mayer Discovery
The first scientist to do a microbial study of tobacco mosaic disease. Established the infectious nature of the disease by showing that juice from the ground up leaves of an infected plant could trigger disease in healthy plant
1898 Beijerinck discovery
Published the same observation (Unaware of Ivanovskys work) but concluded agent was not a bacterium, instead a “Contagium vivum fluidum”
Exception to the first rule of Koch’s Postulate
Asymptomatic cases in some hosts but diseased cases in others
1893 Ivanovsky Discovery
Tobacco mosaic disease was caused by a filterable agent
1898 Loeffler & Forsch Discovery
Causative agent of foot and mouth disease was filterable
Advances made in plant virology
-Ability to isolate large amounts of viruses from plants permitted extensive chemical and physical analyses
-First demonstration that viruses consisted of proteins and nucleic acids
-Crystallization of TMV by Stanley was a paradigm shift in that it demonstrated that the ability of an agent to produce copies of itself resided in its macromolecule
Filterable agent
An agent smaller than a bacteria that can be separated to prove the pathogenicity and disease is linked to a smaller virus and not a bacteria itself
Toxin definition
A poisonous substance, especially a protein, that is produced by living cells or organisms and is capable of causing disease when introduced in the body
