Infectious disease Flashcards
Malarial diseases
- Plasmodium Falciparum- Vivax- Malariae- Ovale- Knowlesi
What is the primary malarial vector?
- Anolpheles
What are the 4 HIV genes and what does each contain?
- Gag - P24 (capsid), P17 (matrix)- Pro - Protease- Pol - RT, Integrase- Env - Gp 120 and 41
What are the HIV gene regulatory regions and what do they regulate?
- 5’ - RNA transcription initiation- 3’ - termination and polyanenylation - Important for integration
Describe the Herpesvirus genome and function.
- 100 genes- Immediate early genes - Shut off host cell protein synthesis and distruction of mRNA and DNA- Early genes - Replication of DNA and formation of concatemers- Late genes - Formation of envelop and capsid proteins
What are the diseases caused by EBV?
- Infectious mononucleosis- Nasopharyngeal carcinoma- Burkitt’s lymphoma- Hodgkins lymphoma- Gastric carcinoma
What is the pathogenesis of EBV?
- Infects B cells and epithelial cells of the oropharynx- Acts as mitogen to B cells increasing proliferation and release of heterophile antibodies through the binding of CD21 and MHC 2.- T cells respond against infected cells through rapid proliferation (lymphocytosis) and produce atypical CTL’s (Downey bodies)
How do patients present with EBV?
- Children normally asymptomatic- Teens and adults present with lymphadenopathy (especially posterior cervical and auricular), fatigue and flu like symptoms.
What is the isotype of the heterophile antibody that is produced in EBV and what complications does this create?
- IgM- Antibodies can develop against ampicillin
What type of herpesvirus is EBV?
- Gamma
What type of herpes virus is MCV?
- Beta
What diseases are associated with MCV?
- Infectious mono- Congenital abnormalities - AIDS- Organ transplant patients
How does CMV evade CTL’s?
- Inhibits translation of MHC 1
How does transmission differ between MCV and EBV?
- EBV - salivary transmission- MCV - Often sexual transmission
How does presentation differ for MCV?
- Pharyngitis with exudate rarely seen- Heterophile antibody negative
How does MCV effect immunocompromised patients?
- Transplant - latent in many tissues, fever, leukopenia, hepatitis, pneumonitis, esophagitis, gastritis, colitis and retinitis. Graft rejection- AIDS - intestinal tract. Colitis and diarrhea, meningoencephalitis.
How is MCV diagnosed?
- Culturing, PCR, immunofluorescence, histological stain with owl eye inclusions.
In EBV what antigens remain following the loss of heterophile antibodies?
- Viral capsid antigen (VCA)- Early antigen
What are the hemorrhagic fever viruses?
- Flavivirus - Dengue - +ssRNA- Filovirus - ebola and marburg -ssRNA
What are the five types of ebola viruses?
- Human - Zaire, Sudan, tai forrest and Bundybugyo- Primate - Reston VA
What caused the Marburg outbreak in Germany?
- African Green monkey’s
What is the structure of the filovirus?
- Helical capsid within an envelope which contains Glycoprotein that mediates attachment and entry of virion into host cell.- Within envelope - RNA dependent RNA polymerase, transcription factor (VP 30) and polymerase cofactor (VP 35)
Pathogenesis of filovirus
- Infects and replicates within DC’s and macrophages- Inoculation site to regional lymph nodes to spleen and liver and other lymphoid tissue - Impaired antibody production allowing virus to proliferate. - Systemic release of cytokines leads to systemic inflammation and increased vascular permeability.- Activation of TF leads to systemic clotting- DIC, shock, systemic hemorrhage and multiorgan failure.
Flavivirus structure
- ssRNA- Icosahedral, enveloped- Envelope made of M protein and E dimer
