viral pathogens II Flashcards
whats the typical course of HIV-1 infection
in a untreated patient, ten billion virions are made and destroyed every day during the chronic phase of disease
the inexorable depletion of CD4 T cells during infection leads to immunodefiicency and mortalilty
virus pathogenesis
Viruses must evade immune responses. Some immune responses are mediated by specific cells of the immune system. These immune cells recognize and kill cells infected by virus.
To evade this type of immune response, some viruses replicate in the immune cells whose function is to recognize and kill infected cells.
Replication in immune cells hides the virus from immune cells and inhibits immune cell function.
Inhibition of immune cell function allows other pathogens to replicate in virus infected hosts and, thus, disease occurs.
Inhibition of immune cell function allows other pathogens to replicate in virus infected hosts and, thus, disease occurs: Opportunistic infections of HIV associated pathogens.
HIV associated pathogens
Virus Herpes simplex virus (HSV) Kaposi's sarcoma herpesvirus (KSHV) Bacteria Mycobacterium tuberculosis Salmonella Fungus Candida Cryptococcus neoformans Parasite Cryptosporidium Toxoplasma gondii
AIDS: cancers and opportunistic infections
Two possible routes of infection (i) primary infection
(ii) reactivation from latency
Primary infection can be resolved (typically by immune suppression) and infection moves to sites in the host that the immune system does not access. In these sites the virus resides without replicating: latency
Reactivation from latency occurs upon immunodeficiency
viruses that cause cancer
Human papilloma virus epstein-barr virus hepatitis b virus hepatitis c virus human herpes virus human t lymphotrophic virus merkel cell polyomavirus
