The document discusses the effects of viruses on host cells, including cytocidal effects, cellular proliferation, malignant transformation, and steady state infections. It details various cytopathic effects observed in tissues, such as inclusion bodies that are characteristic of specific viruses, along with their staining properties and classification. The types of inclusion bodies are explained, including intracytoplasmic and intranuclear types, with examples like Negri bodies and Guarnieri bodies.

1. Viruses cause…
 Cell death (cytocidal effect)
Eg: Poliovirus.
 Cellular proliferation
 Eg:Molluscum contagiosum.
 Malignant transformation
 Eg:Oncogenic viruses.
 Some virus and host cell enter into a peaceful
coexistence-’Steady state infection’.

2.  Seen in tissue culture
 Viral infection of cells leads to readily observable
cellular changes called cytopathic effects
 Enteroviruses- crenation of cells and degeneration
of cell sheet HEMA
 Measles- syncytium formation
 Adenovirus – bunch of grapes
 Herpes virus – discrete focal degeneration

3. Cytopathic effects
Lead to observable cellularLead to observable cellular
changes in tissue culture.changes in tissue culture.

4. Inclusion bodies….(SN,MCQs)
Structures with distinct size, shape, location and
staining properties that can be demonstrated in virus
infected cells under the light microscope.
CLASSIFICATION
They may be situated at:
 Cytoplasm (intracytoplasmic)- pox virus
 Nucleus (intranuclear)- herpes
 Both - Measles

5. Appearance of Inclusion body….
• They are generally acidophilic.
• Seen as pink structures when stained with giemsa or
eosin methylene blue.
• Some viruses form basophilic inclusions.
Eg: Adenovirus.

6. General features…
 May be crystalline aggregates of
virions.
Made of virus antigens present at the
site of virus synthesis.
Represent degenerative changes
produced by viral infection.

7. Intracytoplasmic inclusion bodies
Negri bodies-Presumptive diagnosis of rabies.
Guarineri bodies- small multiple inclusions.
eg- Vaccinia(small pox) virus.
 PASCHEN Bodies
Bollinger bodies- large inclusions.
eg- Fowl pox virus.
Molluscum bodies- very large 20-30µ.
eg- Molluscum contagiosum.

8. Negribodies:Intracytoplasmic IB in the neurons,
abundant in the cerebellum & hippocampusMCQ
SQ
MF

9. Negri body

10. Negri body in infected
neuron.

11. Guarnieri bodies- small multiple
inclusions.
eg- Vaccinia(small pox) virus.

12. Guarnieri bodies

13. Molluscum bodies- very large 20-30µ.
eg- Molluscum contagiosum.

14. Molluscum bodies

15. Intranuclear inclusion bodies
Classified by Cowdry- 2types
Cowdry type A inclusions: variable and
granular
Eg-herpesvirus, yellow fever virus.
Cowdry type B inclusions: circumscribed and
multiple
Eg- Adenovirus, Poliovirus.