Viral Infections Intro + AIDs Flashcards
Enumerate diseases caused by viral infections
- Acute illness (common cold)
- Lifelong latency & long term reactivation (herpes)
- Chronicity: HIV
- Neoplasia (tumors)
Mention the disease spectrum associated with viral infections
- Host lytic infections: body gets rid of virus but destroys some of its cells
- Abortive infection: Virus couldn’t complete its replication (due to lack of factors of replication or action of host immunity)
- Persistent infection: remains over long period of time (with symptoms)
- Latent infection: Delay between infection & appearance of symptoms
- Transformation –> tumor cell (oncogenic viruses)
Example of Latent viral infection
HSV1 (herpes): triggered by stress, fever blisters/ cold sores appear
Cellular changes during Viral infections
- increased Cell proliferation –> warts
- degenration & necrosis (in viral hepatitis & polimyelitis)
- Apperance of inclusion bodies (negri bodies)
Causative organism for AIDS
Human Immunodeficiency Virus
Mechanism of HIV in causing AIDS
- Has reverse transcriptase enzyme
- therefore severing the action of CD4 receptors & T helper cells
Means of transmission of HIV
- Sexual contact
- Parentral (injection)
- from infected mothers to newbrons
Indivisuals at high risk of contacting HIV
- Homosexuals
- Drug abusers
- Hemophilics
- Blood recepients
- Sexual partners
- Children of person with HIV
Phases of AIDS is divded into:
- Early Acute Phase/ Group 1
- Middle Latent Chronic Phase/ Group 2
- Final Crisis/ opportunistic infection & tumors phase/ Group 3
Charactaristics of Early Acute phase of AIDS
- High virus replication
- Acute illness
- Non-specific symptoms: Sore throat, muscle pain, fever, skin rash
Charactaristics of Latent chronic/ middle phase of AIDS
- Low virus replication
- May be asymptomatic
- May have Generalized Lymphadenopathy
Charactaristics of Final crisis phase of AIDS
- Breakdown of host defense
- Increased viral replication
Leading to: opportunistic infections or Malignancy
Main cause of Death in AIDS
Opportunistic infections
Examples of opportunistic infections in AIDS
Protozoal:
* toxoplasmosis
* Pneumocytosis
Fungal:
* Candidiasis
* Cryptococcosis
* Histoplasmosis
Bacterial:
* Tuberculosis
* atypical mycobateriosis
* Salmonella
* Shigella
Viral:
* Cytomegalovirus
* Herpes simplex
* Varicella-Zoster virus
Examples of Malignancies in AIDS
- Kaposi’s Sarcoma
- Primary CNS Lymphoma
- Burkitt’s Lymphoma
- Non-Hudgkin’s Lymphoma
