2. Action of Animal viruses
1. Tumor cell division.
2. Multiplication of virus, then death of
infected cell which cause release of virus.
3. Multiplication of virus with out causing
death to infected cell and slow release of
virus.
3. Cultivation of animal virus
A. In living animal.
B. in In Embryoted egg.
C. By Cell culture.
4. Isolation, Cultivation and Identification of
animal viruses
1. Cultivation/ Isolation:
A. In living animals:
• Using live animal such as: mice, rats, rabbits, guinea pigs, hamster, chickens, and
monkey.
• The animal is exposed to the virus by injection of a viral preparation or specimen
into the brain, blood, muscle, body cavity, skin, or footpads.
• Use in research to study the immune system’s response to viral infections.
Ex.
HIV: immunodeficient mice grafted to produce human T cells and
human gamma globulin.
5. Cont.
Isolation, Cultivation and Identification of animal
viruses
2. Identification
The signs of viral growth include:
1. Death of the animal.
2. Defects in animal development.
The infected animal tissue can be prepared for examination with an electron
microscope.
6. Isolation, Cultivation and Identification of animal
viruses
B. In Embryoted egg
1. Cultivation/ Isolation
Use embryonated chicken, duck or turkey for inoculation of viral suspension.
2. Identification
The signs of viral growth include:
1. Death of the embryo
2. Defects in embryonic development.
3. localized areas of damage in the membranes, resulting in discrete, opaque spots called pocks (a
variant of pox).
•The embryonic fluid and tissue can be prepared for examination with an electron microscope.
•Some can also be detected by their ability to agglutinate red blood cells or by their reaction with an
antibody of known specificity that will affix to its corresponding virus, if it is present.
7. The virus
injection site
1. Target the embryo.
2. Target the Amniotic cavity.
3. Target Chorioallantois membrane.
4. Target Yolk sac.
8. Viral culture in eggs:
Some viruses, such as influenza viruses,
are grown in embryonated chicken eggs
9. Isolation, Cultivation and Identification of
animal viruses
C. Using cell culture
1. Cultivation/ Isolation:
•Preferred type of growth medium for virus, more convenient than the previous two methods.
•Use isolated cell from animal that are cultured in vitro. Normal cells will form monolayer.
10. Cont.
Isolation, Cultivation and Identification of animal
viruses
2. Identification
If viruses are present, the cells of monolayer will deteriorate as they multiply.
Cell deterioration is called cytopathic effect (CPE).
CPE can be detected and counted by:
1. plaques by phages (plaque assay).
2. Microscopic observation via electron microscope (histopathology).
11. Identification of viruses
1. PCR – polymerase chain reaction.
2. Restriction fragments polymorphisms (RFLP).
3. Serological method – Western blot.
4. Immunological test , ELISA.
