12th Zoology

Viral Diseases

Viral Diseases

A. Cancer and Viruses

Viruses have been identified as one of the causative agents for
cancer or tumour. Such tumour inducing viruses are called oncogenic
viruses. Adenoviruses, polioma virus, simian virus 40 (SV 40), Epstein-Barr
virus (EBV) ( a herpes virus) are oncogenic DNA viruses. The RNA sarcoma
viruses are oncogenic RNA viruses (eg., Rous sarcoma). Viral Diseases

B. Rabies Virus and Rabies disease

Rabies virus belongs to the rhabdovirus family. It is a parasite of
domestic and wild mammals. The transmission to humans occurs through the
bite of an infected animal. Dogs, cats, bats, are the mammalian animal sources
for the rabies virus.
In humans, the symptoms of rabies are severe headache, high fever,
alternating excitement and depression, muscular spasms in throat and chest,
hydrophobia etc. The incubation time in humans is usually about 3 to 8 weeks
but it may also vary. If untreated the mortality rate from rabies is 100 percent.
The new rabies vaccine was discovered in 1980. It is an inactivated
vaccine prepared from the virus propagated in cultures of diploid human
cells. This vaccine is both safe and highly immunogenic. Viral Diseases

C. Pox virus

Pox viruses are the largest of all viruses and are brick shaped. They
contain double stranded DNA, protein and lipid. They have a dum bell shaped
nucleoid surrounded by two membrane layers.
Variola virus is called the small pox virus. It is transmitted by droplet
infection either directly from the infected person or by handling articles
infected by the patient. Small pox is completely eradicated. The small pox
vaccine consists of vaccinia, closely related to variola. It gives protection
both by humoral and cell mediated immunity.
Other pox viruses are chicken pox and measles viruses. Viral Diseases

D. Hepatitis-B

Hepatitis B virus (HBV) is an enveloped virus with a double stranded
DNA. This causes jaundice and hepatic carcinoma. This disease is deadly
and more infective than AIDS. HBV vaccine consists of purified HBV Ag
(Australian antigen) obtained from the blood serum of apparently healthy
carriers. Viral Diseases

Related Topics in Zoology:

Bio Zoology All Important Topics

  1. Microbiology Introduction and History of Medical Microbiology

  2. Pasteur, Koch, Lister

  3. Structure of Viruses

  4. Viral genetics

  5. Virus Culture

  6. Viral Diseases

  7. Bacteria Structure Culture

  8. Bacterial Genetics

  9. Bacterial Diseases

  10. Protozoan microbiology

  11. Pathogenecity of Microorganisms

  12. Antimicrobial Resistance

  13. Antibiotics and Chemotherapy

  14. AIDS – HIV

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