How do scientists identify viruses?

Many people wonder how scientists can determine what causes SARS (a virus that causes severe emergency absorption syndrome) in particular and viruses in general?

1. Basic rules for determining infectious organisms

In 1890, Robert Koch pointed out the basic rules for scientists to use to determine if an infectious organism causes a particular disease. These four rules are called the "Koch Principles."

  • The pathogen must always be found on infected organisms but not in healthy organisms.
  • The pathogen must be kept in experimental conditions outside the organism.
  • The pathogen must be capable of causing the disease when infecting a desensitized animal.
  • The pathogen must be determined from the results of re-isolation.

Kock Principles

Heinrich Hermann Robert Koch was a German doctor who developed the Kock Principle

For example, in the case of the discovery of the SARS virus (sometimes shortened to SARS-CoV), scientists found and developed from some sick people with symptoms of SARS – thus completing koch's first two principles. Because the exposure to the virus is not justified, scientists have used a technique called epidemiology to prove that only people exposed to the virus are infected. The technique relies on surveying and studying groups of people with the disease and comparing them to those who do not. The researchers then assumed that the disease would be contagious if a person was exposed to the disease. Then they continued to look for whether new people were accidentally exposed to the disease and that creature was developed from them. This meets Koch's third and fourth principles.

In the case of SARS, scientists have clearly in point that the virus is associated with people with the disease and the virus has been isolated from these patients. Epidemiology also shows that the disease occurs in people who are exposed to the disease more often than those who have not been clearly exposed to the disease. Eventually, the virus was developed from people who were later exposed.

In addition, scientists can use animals to prove these last two rules by exposing the animal to the virus and see if it causes diseases such as SARS?

SARS virus

Virus SARS

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Article reference source:,


  • SARS: What to know
  • Is Progressive Respiratory Distress Syndrome (ARDS) dangerous?
  • Acute respiratory distress syndrome in adults

  • Descriptive epidemiology: Things to know
  • Methods of study of epidemiology
  • The role and meaning of epidemiology

About: John Smith

b1ffdb54307529964874ff53a5c5de33?s=90&r=gI am the author of I had been working in Vinmec International General Hospital for over 10 years. I dedicate my passion on every post in this site.


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