corona viruses

                                   corona viruses
Definition*
corona virus is not the only one type of virus.The word corona named because of its morphology by resembling it with crown due to its surface projections.

*Reference:
Tyrrell DA, Almeida JD, Cunningham CH, et al. Coronaviridae. Intervirology. 1975;5:76–82.

History of corona viruses
 
In the 1960s, corona viruses that were related to human beings appeared in children caused the upper respiratory tract infection in children. There are about five types of corona viruses that have been identified. Some of them affect both lower and upper respiratory tract disease.   

In 1965, a virus named B814 by Bynoe and Tyrrell discovered. Such virus was present in respiratory track in adults and more precisely related to the embryonic tracheal organ cultures of the track of the respiratory system. 

Tyrrell and Bynoe work infected the human volunteers by cold and but both were not successful in tissue culture.

Hamre and Procknow were successful for tissue culturing of the viruses obtained from a sample of the infected cold volunteers. Both the virus, B814 and one which was discovered by Hamre then named as 229E.The organ culture virus named "OC" obtained by a similar method by Tyrrell and Bynoe.

The electron microscopy showed the results of organ cultures B814 virus which were matching with infections bronchitis of chickens by Tyrell and Almeida and about  (80 to 150)nm-sized particles. These particles were membrane coated and pleomorphic. Tyrell worked on viruses and holding the group of virologists. They worked on the strains of humans and several viruses of animals as well. In there work, they studied the viruses related to mouse hepatitis, bronchitis, transmissible gastroenteritis of swine and proved such viruses same in morphological pattern. such a new genus of viruses was named as corovirus as their crown-like morphology.  


Corona virus effect by age

 According to different reports/results, in the duration of epidemics causes viral activity about 35% of the total respiratory and the adult colds was about 15%.
coronaviruses related to the respiratory system cause illnesses with pneumonia in infants and young adults, asthma exacerbations in children and chronic bronchitis in adults and the elderly.
 
Corona virus effect by temperature/ weather
The coronavirus (respiratory) effects more in winter and spring than as compare to summer and fall.

Effect of corona viruses on animals

 The corona virus affected pigs rats, dogs mice, cats, rabbits and chickens, turkeys and calves and caused mice with disease of gastroenteritis,hepatitis, and encephalitis, sialodacryoadenitis and pneumonitis in rats, peritonitis virus in cats.
 
corona viruses have a family which are categorised mainly into
- SARS-CoV (2002–2003)  
-MERS-CoV
-Coronavirus disease (COVID-19)  (December-2019)

 How corona viruses spread?
  -person to person 
     Effected person to another person after sneezing, coughing and small    
    droplets injected to other healthy person. 
-  Zoonotic
    such viruse are transferred from animals to human being an are known as   
    zoonotic. 


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Sources

- McIntosh K, Becker WB, Chanock RM. Growth in suckling-mouse brain of “IBV-
  like” viruses from patients with upper respiratory tract disease. Proc Natl Acad 
  Sci USA. 1967;58:2268–2273.

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-  Witte KH, Tajima M, Easterday BC. Morphologic characteristics and nucleic 
   acid type of transmissible gastroenteritis virus of pigs. Arch Gesamte 
   Virusforsch. 1968;23:53–70.


-  McIntosh K, Kapikian AZ, Turner HC, Hartley JW, Parrott RH, Chanock RM. 
   Seroepidemiologic studies of coronavirus infection in adults and children. Am J
   Epidemiol.
   1970;91:585–592.

- McIntosh K, Chao RK, Krause HE, Wasil R, Mocega HE. Coronavirus infection in
   acute lower respiratory tract disease of infants [see comment]. J Infect Dis.   
    1974;130:502–507.

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   infections in military recruits. Three-year study with coronavirus strains OC43 
   and 229E. Am Rev Respir Dis. 1974;109:621–624.

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-  McIntosh K, Ellis EF, Hoffman LS, Lybass TG, Eller JJ, Fulginiti VA. Association 
   of viral and bacterial respiratory infection with exacerbations of wheezing in 
   young asthmatic children. Chest. 1973;63(suppl):43S.

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-  Falsey AR, McCann RM, Hall WJ, et al. The “common cold” in frail older 
    persons: impact of rhinovirus and coronavirus in a senior daycare center. J 
    Am Geriatr Soc. 1997;45:706–711.

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-  Falsey AR, Walsh EE, Hayden FG, et al. Rhinovirus and coronavirus infection-
   associated hospitalizations among older adults. J Infect Dis. 
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  .