Infection Flashcards
Bacteria
Lack cell organelles and have a cell wall. Can be aerobic or anaerobic and Gram +/-ve. Cocci are round while bacilli are rods. Most are extracellular.
Besides our skin, what is our primary line of defence to pathogens?
Enzymes, acids, detergents, IgA, coughing, cilia, and macrophages.
Can the immune response cause tissue toxicity?
Yes.
Cytopathic-cytoproliferative inflammation
Caused by virus-mediated damage. Causes: a) viral aggregates (inclusion bodies - w/i cells - like cold sores) b) cell fusion (like Measles) c) discohesion B blisters d) proliferation of host cells (neoplasia, like in HPV)
Describe the body response to helminths:
Lay eggs and cause inflammation to them.
Direct toxicities
Includes viral lysis, enzymatic degradation of cellular structures, and cell damage upon invasion.
Diseases associated with prions:
CJD - Creutzfeld-Jacob disease Mad Cow disease (variant of CJD) BSE - bovine spongiform encephalopathy
Diseases associated with viruses:
Acute (colds, influenza), chronic (hep B/C), latent (herpes zoster) Can also cause neoplasia.
Do bacteria form inclusion bodies?
Nope. They form clumps of cells.
Ectoparasites
Usually insects or arachnids. They attach to and live on the skin. Examples include ticks, fleas, lice (what is an arthropod vector??) Can cause disease directly or be vectors.
Fungi
Thick cell walls and cell membranes; many are flora; likely a culprit in opportunistic infections.
Give an example of a flora that is beneficial to the host.
Flora that produce Vitamin K in humans.
Granulomatous inflammation B
Occur usually with fungal infection or TB. Contains lymphocytes, macrophages, and histocytes (altered macrophages).
Helminths
Multicellular parasitic worms of three classes: 1) roundworms (nematodes - ascaris, hookworms) 2) flatworms (cestodes - pork, beef, fish, tapeworms) 3) flukes (trematodes - schistosomes)
How do cytokines influence our immune system (hum oral)?
They primarily initiate an inflammatory reaction. They can activate inflammatory cells or regulate their growth and differentiation.
Humoral immunity usually combats what kind of infection?
Bacterial infections
In what case can body flora cause an infectious response, and give an example?
When one is immunocompromised - opportunistic infection. The fungus Candida albicans.
In what case can viruses be seen via light microscopy?
When they form inclusion bodies.
Indirect toxicities
Include release of toxins with remote effects including cell damage, cellular dysfunction, vascular damage, and ischemic necrosis.
List all the stains that can be used on some infectious agents.
Gram (+ means thick cell wall), acid-fast, silver, specific Ab-labelled immunohistochemical stains.
List Koch’s postulates:
The organism: 1) must be found in lesions of the disease 2) must be isolated and cultured in vitro 3) must transmit the disease to another animal 4) must be recovered from lesions in that animal
List three methods that infectious agents use to cause tissue damage:
1) directly cause cell death 2) release toxins and enzymes 3) induce host cellular responses
Mononuclear and granulomatous inflammation
Response to viruses, intracellular bacteria, or parasites. Characteristic of lymphocytosis (increase in []).
Name the 3 main types of bacteria that are atypical or intracellular:
1) chlamydia (don’t produce ATP either) 2) Rickettsia (can be arthropod vectors - lice, ticks, mice) 3) mycoplasma (no cell wall)