M18: Ingestion-Acquired Pathogens Flashcards
Introduction to the Establishment of Infectious Diseases:
Pathogen transmission typically (but not always, e.g. endogenous infections are caused by _) plays an important role in the infectious disease cycle.
The initial symptoms of an exogenous infection often reflect its _.
Some pathogens can enter the body by multiple routes. An example is _, which can enter via insect bites, cuts, ingestion and inhalation.
normal flora
transmission
Francisella tularensis
Pathogens for Transmission Routes:
Inhalation (respiratory) (2)
Ingestion (2)
Blood (1)
Arthropods (2)
STI (2)
Wounds (1)
M. tuberculosis, influenza virus
Salmonella spp., rotavirus
Hepatitis B virus
Borrelia burgdorferi, Plasmodium spp.
HIV virus, N. gonorrhoeae
C. perfringens
Introduction to the Establishment of Infectious Diseases:
Major routes for pathogen entry (6)
ingestion inhalation blood arthropod bites STD or urinary wound/rupture
Introduction to Ingestion-Acquired Diseases:
Ingestion-acquired illnesses often (but not always) cause _ symptoms, e.g., diarrheal disease of infectious origins is usually acquired by ingestion.
Ingestion-acquired diseases can be _ or _
GI
true infections or intoxications.
Introduction to Ingestion-Acquired Diseases:
Intoxications: _ is sufficient to obtain disease.
i) Foodborne intoxications often involve _- and _-stable toxins.
ii) Symptoms of these intoxications usually develop (slowly / quickly), since toxin is _.
iii) Symptoms of these intoxications often involve the _: (3).
iv) An exception to (ii) and (iii) is _
ingestion of preformed toxin
i) heat- and pH-
ii) quickly, already present
iii) GI tract: vomiting, diarrhea, cramps
iv) foodborne botulism.
Introduction to Ingestion-Acquired Diseases:
Infections: ingested pathogen must be _.
i) Invasive pathogens acquired by ingestion: typically cause _ (often evident by the presence of fecal _, which can be diagnostically useful), as well as such _ symptoms as _, _, and _
Invasive pathogens can typically remain _ (e.g., Shigella spp. or nontyphoid Salmonella) or _ (e.g., S. typhi, hepatitis A virus). Symptoms caused by these invasive pathogens typically develop rather (slowly / quickly) (several days).
present in the body
i) inflammation, leucocytes, GI, cramps, diarrhea and (sometimes) fever.
localized in the GI tract
disseminate
slowly
Introduction to Ingestion-Acquired Diseases:
Infections: ingested pathogen must be _
ii) In vivo _ production by ingestion-acquired pathogens: several _ (e.g., Vibrio cholerae, ETEC, Clostridium perfringens) produce toxins only after they become _.
Usually these toxin-producing bacteria are (invasive / noninvasive) (exception: Shigella dysenteriae).
present in the body.
enterotoxin
bacteria
present in the GI tract
noninvasive
Introduction to Ingestion-Acquired Diseases:
Toxins produced in the GI tract usually cause mainly GI symptoms (diarrhea, cramps), which is why they are referred to as _.
An exception is EHEC, whose toxin (_) not only affects the _ but can also be absorbed into the circulation and then damage the _.
Symptoms of GI diseases involving pathogens producing toxins in vivo usually develop (slower / quicker) than intoxications (but often a little (slower / faster) than illness caused by invasives).
Other mechanisms: EPEC bind to _ and inject effectors into them to alter _ pathways.
enterotoxins
shiga toxin
colon
kidneys
slower
faster
enterocytes
signal transduction
Introduction to Ingestion-Acquired Diseases:
Transmission of Ingestion-Acquired Pathogens:
Some pathogens acquired by ingestion are almost exclusively associated with _ or _ infections (e.g., foodborne botulism).
Other pathogens can be ingested in _, _, or by _ (e.g., Shigella spp.).
Many (but not all) ingestion-acquired pathogens are transmitted via direct or indirect _.
food- or water-borne
food, water, or by direct fecal-oral contact
fecal-oral contamination
Introduction to Ingestion-Acquired Diseases:
Transmission of Ingestion-Acquired Pathogens:
Food poisoning: there are ~30-70 million cases of food poisoning in the USA each year, resulting in 5-9 thousand deaths. In _ countries, these illnesses cause even more deaths (in the millions/year), particularly in _ (this is also true of waterborne infections).
i) >75% of all foodborne disease has a _ origin (once thought this was mostly bacterial, but increasing evidence for viral cause also).
ii) _, _, and _ are most common symptoms, but sometimes also include _.
iii) Typically result from a combination of _, _, and/or _
underdeveloped
young children
i) microbial
ii) Diarrhea, cramping and vomiting, fever
iii) incomplete cooking, poor sanitation during handling and/or poor food storage conditions.
Bacterial Intoxications:
Staph aureus:
Mechanism
Symptoms
heat-stable enterotoxin
vomiting
Bacterial Intoxications: Bacillus cereus (emetic form):
Mechanism
Symptoms
heat-stable enterotoxin
vomiting
Bacterial Intoxications:
Clostridium botulinum:
Mechanism
Symptoms
heat-labile neurotoxin
flaccid paralysis
Bacteria Producing Enterotoxins in vivo:
Clostridium perfringens:
Mechanism
Symptoms
heat-labile enterotoxin
diarrhea, cramps
Bacteria Producing Enterotoxins in vivo:
B. cereus:
Mechanism
Symptoms
heat-labile enterotoxin
diarrhea, cramps
Bacteria Producing Enterotoxins in vivo:
EHEC:
Mechanism
Symptoms
shiga toxin
diarrhea, cramps
Bacteria Producing Enterotoxins in vivo:
ETEC:
Mechanism
Symptoms
heat-labile and heat-stable enterotoxins
diarrhea
Bacteria that Invade the Intestinal Epithelium:
Nontyphoid Salmonella:
Mechanism
Symptoms
Invasion and Inflammation
fever and diarrhea
Bacteria that Invade the Intestinal Epithelium:
Shigella spp.:
Mechanism
Symptoms
Invasion and Inflammation
dysentery/diarrhea and fever
Bacteria that Invade the Intestinal Epithelium:
Campylobacter jejuni:
Mechanism
Symptoms
Invasion and Inflammation
fever and diarrhea
