Lawsonia Intracellularis Flashcards
What animal was lawsonia intracellularis described in before horses?
swine
What type of bacteria is it?
obligate intracellular bacteria
When was the disease isolated and identified?
mid 1990s (newer)
What does the disease produce?
a lot of proliferative enteropathy (multiplies endothelial cells)
Where is the disease found?
worldwide (causes disease in many species)
What is the source of infection in foals?
not yet identified
(possibly deer, foxes, wolves, etc.)
Can lawsonia intracellularis transmit between species?
it has been experimentally demonstrated so it can happen
How is it transmitted?
fecal-oral transmission
What age does the disease generally infect?
younger ages (3-13 months)
What does it mean that lawsonia intracellularis is an emergent disease?
that cases are rising
What does the severity of the disease depend on?
-depends on the load of bacteria ingested
-immune status of the horse
What is the process of the infection?
-bacteria invades dividing intestinal cells
-infected cells continue to divide even if heavily infection
-develops as a progressive proliferation of immature epithelial cells, invaded with intracellular bacteria
What do lesions reduce?
intestinal digestive and absorptive capabilities (leads to diarrhea and weight loss)
The cells are multiply but…
not working correctly
Clinical signs of lawsonia intracellularis:
-depression
-fever
-anorexia
-weight loss
-diarrhea
-colic
-poor body condition
-rough coat
-pot-bellied
-dull
What do we see in the necropsy (pathological findings)?1
-emaciation, subcutaneous edema (swelling under the skin)
-thickening of intestinal mucosa, lesions generally on duodenum and ileum
-muscular hypertrophy of intestinal wall
What is the histology of lawsonia intracellularis?
hyperplasia of epithelium
Lawsonia intracellularis is more ______ than other diseases
chronic
It can be diagnosed by differentiating it from:
Common GI diseases:
-intestinal obstruction
-sand impaction
-parasites
-ulcers
-Salmonella
-Rhodococcus
-Clostridium
-PHF
How is the disease diagnosed?
-clinical signs
-exclusion of other enteric disease
-abdominal ultrasound (to see thickening of intestinal wall, serology
-exclude the more common diseases first
How does treatment with antibiotics work?
they are able to enter the cell as organism is obligate intracellular
What is the main antibiotic used?
Erythromycin (or chlorythromycin)
-PO
-TID
-for 3 weeks
Can you use erythromycin in older horses?
no because it is a macrolide (causes severe and deadly diarrhea)
What has to happen when a horse is taking erythromycin?
they must stay inside
-the antibiotic phoyosynthesizes
What other antibiotics can be used?
-chloramphenicol
-tetracyclines
-metronidazole
What antibiotics do not treat the disease?
-penicilin
-SMZ-TMP
-gentamicin
What would Omeprazole be given for?
preventing gastric ulcers
When should fluids be given during treatment?
if the horse has severe diarrgea
Do horses respond well to treatment?
yes, the biggest issue is diagnosing it
How can it be prevented?
-epidemiology is not very understood so prevention methods are hard to achieve
-isolation of infected foals
-disinfection of barn and stalls (with paraquat, povidone-iodine)
How can lawsonia intracellularis affect humans?
it is not yet considered a zoonotic disease, but the disease has been described recently in primates so we may be susceptible to infection
