Diseases

The condition of the abnormal functioning of the human body is referred as ‘disease’. Disease can be defined as a medical situation which has specific symptoms and indications.

Diseases occur due to external factors or internal functional disorders. Internal functional disorders are generally genetic or immune diseases while the external factors are infectional diseases. Basically the diseases are classified as pathogenic, genetic, physiologic and deficiency disorders.

Infectious diseases are described as pathogenic diseases which are caused by bacteria, virus, fungi or protozoan organisms. Infectious disease are generally contagious; they can be transmitted from animal to human and they can spread between humans. There are various transmission ways of infectious diseases and they are generally transmitted by body fluids. In addition some infections are carried by biological or mechanical vectors. 

9.5 million people die because of infectious diseases annually and 20% of the total mortality rates are caused by infections. Especially respiratory, tuberculosis, HIV-AIDS and gastro-intestinal infections are fatal. Therefore, diagnosis and treatment of these diseases are distinctly important. There are various methods for diagnosis of diseases and they are generally classified as microbial culture, microscope techniques, biochemical tests and molecular based tests. These methods have different advantages and drawbacks. However, it is accepted globally that the most rapid and certain diagnosis methods are molecular based tests. Among the molecular based tests, Real Time PCR method is the most widely used one for in vitro diagnostics. In this technique, genes which are specific for the pathogen are targeted, as a result both the disease is diagnosed and the amount of the pathogen in the body is quantitatively measured. The quantitative determination of the presence of the pathogen in the body can be significant for the choice of treatment method and therapy monitoring. Therefore Real Time PCR method has become the new gold standard for diagnosis of infectious diseases.

References:

 

  1. 1.World Health Organization. (2008) WHO Global Burden of Disease: 2004 update.Available from: www.who.int/healthinfo/global_burden_disease/2004_report_update/en/index.html
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  6. 6.Molecular Approaches to Diagnosing and Managing Infectious Diseases: Practicality and Costs, Michael A. Pfaller, Emerging Infectious Diseases, Vol. 7, No. 2, March–April 2001
  7. 7.Real-Time PCR in Clinical Microbiology: Applications for Routine Laboratory Testing, M. J. Espy, J. R. Uhl, L. M. Sloan, S. P. Buckwalter, M. F. Jones, E. A. Vetter, J. D. C. Yao, N. L. Wengenack, J. E. Rosenblatt, F. R. Cockerill III, and T. F. Smith, Clinical Microbiology Reviews, Jan. 2006, p. 165–256
  8. 8.Multiplex RT PCR in Microbiology, Nick M. Cirino, Norma P. Tavakoli, Susan Madison-Antenucci and Christina Egan, Real-Time PCR in Microbiology: From Diagnosis to Characterization, Chapter 6, Ian M. Mackay, September 2007