An introductory video of large number of video lecture series. This lecture gives an overview of all the outbreaks that has occurred in the past and going on in the present.

1. Introduction to Coronaviruses(SARS,
MERS, COVID-19: Hosts, Symptoms &
History
Part-I
Dr. Rashmi Kumari
Assistant Professor
Department of Zoology
College of Commerce, Arts & Science
Patliputra University, Patna

2. Introduction
Family of RNA viruses in the Nidovirales order
Significant viral pathogens in humans and animals
Corona: prefix comes from the Latin word for Crown (named for “crown-like” appearance of the virus)
Classification: Four categories
1.Alpha
2.Beta
3.Gamma
4.Delta
Human coronaviruses are alpha- and beta- coronaviruses
Medium sized viruses enveloping a positive- stranded RNA ( 120- to 160-nm)
Very large viral RNA genome (27–32 kb)
Source: World Health Organization (WHO)
Negative stain electron microscopy showing a
MERS-CoV particle with club-shaped surface
projections surrounding the periphery of the particle,
a characteristic feature of coronaviruses.
Source: Cynthia Goldsmith/Azaibi Tamin
Diagrammatic representation of single
stranded RNA coronavirus

3. Introduction to coronaviruses
Hosts, Reservoirs and Infected Animals
Infect birds and animals
Bats are hosts to the largest number of viral genotypes of coronavirus
Epidemics can occur when viruses transmit from one species to another
Can cause mutations in the envelope protein that allow viruses to bind to cells
Human
Human coronaviruses are cause of respiratory and gastrointestinal tract infections.
Estimated to account for 5-10% of all adult respiratory tract infections (common cold to pneumonia to ARDS)
GI symptoms include diarrhea
When mutations occur, coronaviruses can be significant cause of human epidemics
Source: World Health Organization (WHO)

4. Coronaviruses: History of Outbreaks in the Past & Present
Source: World Health Organization (WHO)
Severe Acute Respiratory Syndrome (SARS) – 2002/2003
Guangdong Province of China
Betacoronavirus
Transmitted from Bats to Civets to Humans
Began in February 2003 and outbreak lasted till July 2003
More than 8000 total cases, 774 deaths, fatality rate approx 9.6%
Middle East Respiratory Syndrome (MERS) - 2012
Saudi Arabia
Betacoronavirus
Transmitted from camels to humans
More than 2400 cases, 858 deaths, fatality approx 34.4%
2019 Novel Coronavirus (2019-nCoV) - 2019
Wuhan, Hubei province of China
Betacoronavirus
Transmitted from snakes?, but more likely from bats? Bats (in Wuhan animal market)
Leaked from Wuhan P4 Laboratory of Wuhan Institute of Virology
Wuhan Institute
of Virology

5. References:
1. World Health Organisation (WHO) [https://www.who.int/emergencies/diseases/novel-coronavirus-
2019/technical-guidance/naming-the-coronavirus-disease-(covid-2019)-and-the-virus-that-causes-it].
2. Andersen, K.G., Rambaut, A., Lipkin, W.I. et al. The proximal origin of SARS-CoV-2. Nat Med 26, 450–
452 (2020). https://doi.org/10.1038/s41591-020-0820-9.
3. Ji, J.S. Origins of MERS-CoV, and lessons for 2019-nCoV. The Lancet 4, PE93 (2020).
https://doi.org/10.1016/S2542-5196(20)30032-2.
4. Google Images