Infectious Diseases of the Intestines Flashcards
what makes up the digestion at the brush border in the small intestine?
carbohydrases
peptidases
how do intestinal viruses cause disease?
infect certain cells and blow them up
what are the main viruses that impact the intestinal tract?
rotaviruses
coronaviruses
parvoviruses
what does loss of the mucosal barrier lead to?
toxemia/sepsis
what are the possible locations of gastrointestinal tract lesions?
damage to villi: enterocyte injury
crypt injury
altered microvilli
injury to lamina propria, submucosa, and deeper
what are the types of gastrointestinal tract lesions?
inflammation
proliferative
necrotizing processes
functional alterations
lymphangiectasia
disorders of innervation
what does parvovirus damage?
crypt epithelium
what does Mycobacterium avium subsp paratuberculosis cause?
johne’s disease: thickened ileum due to granulomatous inflammation
macrophages expand lamina propria and submucosa
what do rotaviruses cause histologically?
shortening and fusion of villi: jejunum and ileum
which coronoviruses do pigs get?
transmissible gastroenteritis virus
porcine epidemic diarrhea virus
parvovirus requires the host cells to be in _____________________
mitotic division
what does bovine viral diarrhea virus cause histologically?
ulcers throughout gastrointestinal tract: over peyers patches
lymphoid depletion
does enterotoxigenic E. coli cause lesions?
no
who does enterotoxigenic E. coli affect?
neonates: piglets and calves
where does shiga toxin producing E. coli impact?
spiral colon mesentery
gastric submucosa
eyelids
brain (neurological signs)
who does shiga toxin producing E. coli affect?
post-weaning swine: 6-14 weeks
what does Clostridium perfringens cause?
necrohemorrhagic enteritis in all species
what toxin does Clostridium perfringens type D secrete?
epsilon toxin: damage to epithelial cells
which animals are usually affected by Mycobacterium avium subsp paratuberculosis?
ruminants older than 2 years
where are lesions from Mycobacterium avium subsp paratuberculosis?
ileum
cecum
proximal colon
ileocecal valve
where do Brachyspira hyodysentereriae and Brachyspira pilosicoli impact?
cecum
colon
which cells does Lawsonia intracellularis have an affinity for?
crypt cells
which species are affected by Lawsonia intracellularis?
pig
horse
hamster
rabbit
ferret
what are some fungal, fungal-life, and algal diseases of the intestine?
Histoplasma capsulatum
pythiosis: Pythium insidiosum
prototheca
where does Pythium insidiosum impact in the gastrointestinal tract?
stomach
small intestine
large intestine
what are some protozoal diseases of the intestines?
Eimeria/Isospora (coccidiosis)
Cryptosporidium sp
what are the gross lesions in severe coccidiosis?
hemorrhagic and necrotic, except in sheep and goats
what are lesions like in sheep/goats with coccidiosis?
nodular, proliferative (hypertrophic crypt-villus units)
where does Cryptosporidiosis live?
within brush border
small intestine more than large intestine
what are ascarids?
large worms in small intestine
where do hookworms inhabit?
small intestine
where do whipworms inhabit?
cecum
+/- colon
where do small strongyles in horses inhabit?
cecum
colon
how does digestion in the lumen of the small intestine occur (as apposed to the brush border)?
pancreatic enzymes
bile
what is typhlitis?
inflammation of cecum
what kills animals with enteritis/colitis/typhlitis/proctitis?
dehydration
loss of mucosal barrier: toxemia/sepsis
what is proctitis?
inflammation of the rectum
why is diarrhea more life-threatening for young animals?
slower turnover: losing fluids longer
how do infectious diarrheas cause diarrhea?
some get into cells
others make exotoxins
others make secretory toxins
are bacteria more important in large or small animals?
large animals
what does damage to crypt epithelium lead to?
more severe maldigestion/malabsorption +/- exudation of blood, serum, inflammatory cells
diarrhea
what do rotaviruses produce?
secretory toxin: NSP4
do rotaviruses have high or low mortality?
low mortality
where do coronaviruses attack?
villi
jejunum, ileum, colon
what does shiga toxin producing E. coli cause?
edema disease: post-weaning pigs
does enterotoxigenic E. coli cause lesions?
no
is diarrhea or significant mucosal disease typical with shiga toxin producing E. coli?
no
what cells do Salmonella sp survive inside?
enterocytes
M cells
macrophages
what does acute salmonellosis look like in the intestines?
fibronecrotizing and hemorrhagic enteritis
what does chronic salmonellosis look like in the intestines?
button ulcers
how do Clostridium perfringes and C. difficile cause disease?
produce toxins: kill everything they encounter (epithelial cells, vasculature)
where do Eimeria and Isospora (coccidia) impact?
small intestine
large intestine in cattle
what are severe lesions like of coccidiosis?
hemorrhagic and necrotic
sheep/goats different
