Unit 3 - GI Lecture 5 Flashcards
What Salmonella species causes septicemia in pigs?
Salmonella choleraesuis
What Salmonella species causes septicemia in cattle?
Salmonella dublin
What Salmonella species are associated with enterocolitis?
Salmonella typhimurium (horses, pigs, and cattle) and Salmonella Newport
What clinical diseases does salmonella cause?
malabsorptive/maldigestive diarrhea, increased vascular permeability, or secretory diarrhea
What clinical signs are associated with Salmonella?
diarrhea, fever, and abdomonal pain
What gross lesions are associated with a Salmonella infection?
enlarged, fluid filled colon, enlarged mesenteric lymph nodes, fibrinonecrotic (ulcerative) enterocolitis
What tissues should you take samples from for Salmonella diagnosis?
intestine, colon, mesenteric, lymph node
What are the possible causes of fecal salmonella isolation?
the animal has salmonella enteritis or the animal is an asymptomatic carrier (either carrying a pathogenic or non-pathogenic strain)
What evidence for Salmonella enteritis can be found in feces?
heavy growth and a pathogenic stereotype
What species are affected by Lawsonia intracellularis?
pigs and horses
What type of diarrhea is Lawsonia intracellularis the most common cause of in swine?
finishing pig diarrhea
What age of horses are affected by Lawsonia intracellularis?
foals 2-8 months of age
What is the pathogenesis of a Lawsonia intracellularis infection?
- Lawsonia enters cell
- Infected cells continue to undergo mitosis
- Oranism inhibits enterocytes differentiation
- Decreased expression of apical membrane transporters involved in absorption
- Nonabsorbed solutes cause osmotic/malabsorptive diarrhea
What are the 3 distinct forms of Lawsonia infection in swine?
hemorrhagic PE, proliferative - porcine intestinal adenomatosis (PIA), necrotic enteritis
What does PPE look like on histopath?
hypertrophy and hyperplasia of crypt epithelial cells
What are two enteric pathogens that do not necessarily result in diarrhea?
Lawsonia and Johne’s (sheep and goats)
What clinical signs may be seen in swine and foals due to a Lawsonia infection?
variation in growth rates in a group of similar aged animals
What clinical signs may be seen in sheep due to a Johnes infection?
weight loss/wasting
What is Johne’s disease caused by?
Mycobacterium avium subspecies paratuberculosis (MAP)
What type of pathogen is MAP and where does it reside?
facultative intracellular bacterium that resides within the cytoplasm of host macrophages
At what age are ruminants more susceptible to Johne’s disease?
less than 6 months of age
How is Johne’s disease transmitted?
fecal/oral route
What clinical signs are associated with the subclinical phase of Johne’s disease?
there are no overt signs
What clinical signs are associated with clinical Johne’s disease cases in cattle?
weight loss and diarrhea, the animal generally has a good appetitie
What clinical signs are associated with clinical Johne’s disease cases in sheep and goats?
weight loss may be the only indication, +/- diarrhea
What is the primary site of MAP infection?
the ileum
What gross lesions are associated with MAP clinically infected animals?
- thickening and corrugation of the ileal, cecal, and colonic mucosa
- Enlagement of draining lymph nodes
What should be submitted for Johne’s diagnostics ante mortem?
feces and serum
What tests can be done ante mortem do diagnose for Johne’s disease?
serology, fecal culture, PCR
At post mortem, what tissues need to be harvested for diagnosis of Johne’s disease?
the ileum and draining lymph nodes
What lesions are seen post mortem in animals that have Johne’s disease?
granulomatous enteritis and granulomatous lymphadenitis with intracytoplasmic, acid-faast bacteria
What is the histopath difference between an animal that had a Lawsonia infection and an animal that had Johne’s disease?
Lawsonia - mucosa thickened due to hyperplasia of crypt cells, ie. proliferative enteritis
Johne’s - mucosa thickened due to an inflammatory infiltrate ie. A granulomatous enteritis
Viral diarrhea most commonly effects the _____.
young
What are the major viruses that cause diarrhea?
coronavirus, rotavirus, parvovirus, BVD
What species are commonly affected by coronavirus?
calves, pigs, and dogs
What age calves are typically affected by coronavirus?
calves 3-21 days
What age pigs are typically affected by coronavirus?
any age, most common in suckling and nursery pigs
What age dogs are typically affected by coronavirus?
most common in 6-16 week old puppies
Where does coronavirus localize in pigs and dogs?
small intestine
Where does coronavirus localize in bovine?
small intestine and colon
What type of diarrhea does coronavirus cause?
malabsorptive/maldigestive diarrhea
What species are typically affected by rotavirus?
calves, pigs, foals, lambs, rabbits, dogs, +/- cats, poultry, and ferrets
What age are animals typically affected by rotavirus?
it is most common in the first month of life
Where does rotavirus typically localize?
the small intestine
What type of diarrhea does rotavirus cause?
malabasorptive/maldigestive
What is seen histologically in animals with rotovirus?
severe villus atrophy, blunting and fusion, with attenuation of superficial villus epithelial cells
What species are affected by parvovirus?
dogs, cats, mink, and raccoon
What age animals are most commonly affected by parvovirus?
most commonly 4 months old or less
Where does parvovirus localize?
the small intestine
What is the pathogenesis parvovirus causing diarrhea?
- Destroys rapidly dividing crypt epithelial cells
- Superficial villus epithelial cells normally slough
- Cells slough and are not replaced causing villus atrophy
- Villus atrophy is often accompanied by substantial loss of surface epithelium
- Malabsorptive/maldigestive/exudative diarrhea
What gross lesions does parvo cause?
enteritis, paintbrush serosal heomorrhages, and congested mucosa with hemorrhagic contents
What does parvovirus look like histologically?
- Necrosis of crypt epithelial cells
- Loss of crypts
- Villus atrophy, blunting, and fusion due to normal sloughing of epithelial cells
How do you diagnose for parvovirus ante mortem?
fecal ELISA
For parvovirus infections, both the fecal ELISA and FA tests are only reliable during the ____ phase of infection.
active
What is feline parvo called?
panleukopenia
What are the four forms of Bovine Viral Diarrhea?
persistently infected, acute BVD, severe acute BVD, mucosal disease
During gestation, when will infection with BVD cause persistent infection in the calf?
prior to 125 days of gestation
What is the outcome of a calf that becomes persistently infected with BVD?
hald of the PI calves die before they are weaned, they may appear relatively normal and shed the virus for years, or they may develop mucosal disease if super-infected with an antigenically similar cytopathic virus
What population of animals does BVD infect?
immunocompetent, seronegative, non-pregnant animals
What is the primary target for replicatoin of BVDV?
lymphoid tissue which may lead to immunosuppression
What population of cattle gets clinically severe BVDV?
animals that are not persistently infected (ie. They did no get it in utero)
What clinical signs are associated with severe acute BVD?
high fever, oral ulcerations, eruptive lesions of the coronary band and interdigital cleft, diarrhea, +/- thrombocytopenia
What is mucosal disease due to BVD caused by?
PI calf + survives post-weaning + superinfected with an antigenically similar strain of BVD
What clinical signs are associated with mucosal disease caused by BVD?
severe pyrexia, leukopenia, depression, weakness, profuse bloody diarrhea, and rapid dehydration
What gross lesions are associated with mucosal disease caused by BVD?
extensive erosions and ulcers are evident throughout the digestive tract, laminitis, and erosive interdigital lesions
What are some intestinal protozoa that are associated with diarrhea?
Coccidia, Cryptosporidia, Giardia, Tritrichomonas fetus
What protozoa is the most economically significant cause of disease of domestic animals?
Coccidia
What are the risk factors for Coccidia infection?
young, no previous exposure, large exposure dose, and stress
What clinical signs are associated with Coccidia?
decreased weight gain/weight loss and diarrhea
What species get significant disease from a coccidia infection?
calves, lambs, kids, piglets, and poultry
What species get minor disease from a Coccidia infection?
dogs and cats
What type of diarrhea is associated with Coccidia infection?
malabsorption/maldigestion
How does Coccidia cause malabsorptive/maldigestive diarrhea?
it causes destruction of villus epithelial cells and villus atrophy and it causes decreased enterocyte function
How does Coccidia cause increased vascular permeability?
it causes inflammation +/- ulceration which leads to increased vascular permeability
What species are affected by Cryptosporidia?
calves, lambs, kids, foals, piglets (reptiles, birds)
What age are animals typically affected by Cryptosporidia?
it is most common in animals less than 6 weeks of age
Where does Cryptosporidia localize?
the distal half of the small intestine - particularly the ileum
What is the mechanism of diarrhea associated with cryptosporidia?
occupation of surface with disruption of microvillus structures and vilus atrophy which causes malabsorption/maldigestion
