Hamster Bacterial diseases Flashcards
What are other names for Lawsonia intracellularis infections in hamsters
- “Wet Tail”
- Proliferative ileitis
- Transmissible Ileal Hyperplasia
Wet tail has ____ morbidity and ____ mortality in _____. Susceptibility decreases from ______ weeks
- high
- high
- weanling hamsters
- 6-10
Clinical signs of Lawsonia intracellularis infection in hamsters
- runting, emaciation, lethargy, unkempt hair coat, anorexia, dehydration
- Foul-smelling, watery diarrhea, soiling of the perineum (“wet tail”)
- rectal prolapse or intussusception
Lawsonia intracellularis - gross findings
- abrupt segmental thickening of the ileum
- prominent serosal nodules and fibrinous peritoneal adhesions
For how long are lesions d/t L. intracellularis hyperplastic?
What do they transition to afterwards
- ~ first 3 weeks
- inflammatory and necrotizing
Lawsonia cellularis - histopath findings
- marked crypt and villus epithelial hyperplasia
- varying degrees of necrosis and hemorrhage
- crypt herniation, destruction, and inflammation
- granulomatous inflammation
What stain would you use to ID Lawsonia intracellularis?
Where would you see the bacteria?
- Warthin-starry stain
- you’ll see clusters in the apical cytoplasm of enterocytes
Lawsonia intracellularis
1. diagnosis
- transmission
- Warthin-Starry stain of bacteria in apical cytoplasm; PCR of feces; Serology
- Fecal-oral route
Lawsonia intracellularis
prevention and control
- Use trusted vendors
- Quarantine and isolate hamsters with diarrhea
- aggressive abx treatment with nutritional supplementation
- depopulation and decontamination are most reliable control
Clinical signs of Clostridioides difficile enterotoxemia
- profuse diarrhea
- high mortality
What can cause an overgrowth and infection via Clostridioides difficile?
dysbiosis due to antibiotic or dietary changes; but can be spontaneous
Which antibiotics predispose a hamster to C. difficile enterotoxemia
- gram (+) targeting-drugs (the mycins, cephalosporins, gentamicin, penicillin)
C. difficile - gross findings
C. difficile - histo lesions
- acute pseudomembranous necrohemorrhagic thyphlitis with edema, leukocytic inflammation, and mucosal hyperplasia
Which syndrome is associated with the aftermath of clostridial enteropathy?
Cecal mucosal hyperplasia of uknown etiology
Cecal Mucosal hyperplasia of uknown etiology
1. affected ages
2. clinical signs
3. gross lesions
- suckling and weanling hamsters
- diarrhea, runting, high mortality
- cecum is congested, contracted, and opaque with mucosal hyperplasia
Causative agent of Tyzzer’s disease
- Clostridium piliforme
Which types of hamsters are most affected by Tyzzer’s disease
- weanling hamsters and immunocompromised hamsers
Where can you find lesions associated with Tyzzer’s disease
- liver – multifocal hepatic necrosis w/ leukocytic infiltration; intracellular bundles of bacteria within hepatocytes at periphery of necrosis
- intestine (lower ileum, cecum, colon) – edema of lamina propria with granulocytes; bacteria within enterocytes and smooth muscle cells
- may also see multifocal granulomatous myocarditis
clinical signs of Tyzzer’s disease
- diarrhea
- ruffled hair coat
- high mortality in susceptible animals
What stains can help to ID C. piliforme
- Warthin-Starry stain
- Giemsa staining
C. piliforme
1. transmission
2. diagnosis
3. Prevention and control
- oral ingestion of spores shed in feces
- ID bacteria inside cells; Giemsa or Silver stains
- isolation of affected animals; sanitation to remove spores
Which age of hamsters may be affected by Helicobacter?
aged hamsters
clinical signs of Helicobacter infection
- usually subclinical
- chronic wasting without diarrhea
Gross lesions of Helicobacter
Which organs can be affected
- combination of inflammation and epithelial hyperplasia
— hyperplastic lesions may progress to dysplastic or neoplastic changes - gastritis (gastric adenocarcinoma)
- Bile duct inflammation and hyperplasia, portal hepatitis and fibrosis (nodular dysplasia w/ H. bilis)
- Pancreatitis
- Proliferative and dysplastic typhlocolitis
— mucosal thickening w/ epithelial hypertrophy and crypt hyperplasia
— chronic lymphohistiocytic and neutrophilic inflammation - stomach, liver, bile ducts, pancreas, colon
Helicobacter
1. diagnosis
- transmission
- PCR; histology is characteristic
- fecal-oral; direct contact; fomites
T/F some spp. of Helicobacter are zoonotic
true; can cause disease in immunocompromised people
T/F Syrian hamsters are very susceptible to bacteremic S. enterica infectiosn
True
T/F Salmonella enterica is not zoonotic
false; it is
Clinical signs of Salmonellosis in hamster
- depression
- ruffled hair coat
- anorexia
- dyspnea
- high mortality
Salmonella enterica (hamster)
Gross findings
- multifocal pinpoint pale foci in liver, patchy hemorrhage in lungs and lymph nodes
Salmonella enterica (hamster)
histo findings
- multifocal interstitial lung inflammation, intra-alveolar hemorrhage, septic thromboemboli in lungs
- multifocal splenic necrosis or splenitis and necrotizing hepatitis with venous thrombosis
- embolic glomerular nephritis
What is a predominant feature of tularemia in hamsters
splenic involvement – enlarged spleen with multiple pale foci
causative agent of tularemia
Francisella tularensis
T/F francisella tularemia is not zoonotic
false; it is zoonotic
Clinical findings of tularemia
- very high mortality
- hunched, ruffled fur, death within 48 hours
Gross findings of francisella tularensis (hamsters)
- splenomegaly w/ multiple pale foci, pulmonary hemorrhages, pale swollen livers
Histo findings of francisella tularensis (hamsters)
lymohoid necrosis, multifocal hemorrhage, and intralesional bacteria
Which ages of hamsters are susceptible to Cryptosporidium muris and parvum
- infant and aged hamsters
– aged hamsters shed higher # of oocysts for C. parvum
– infants shed higher # of oocysts for C. muris
Histopathological findings of cryptosporidium in hamsters
- organisms attached to villus surface
- villus attenuation, crypt hyperplasia in small intestine
Which protozoal parasite can cause diffuse thickening of the small intestine, cecum, and colon
Giardia muris
Giardia muris (hamsters)
- clinical signs
- infections common but usually subclinical
- chronic emaciation and diarrhea in aged hamsters
Giardia muris (hamsters)
- gross findings
- diffuse mural thickening of small and large intestine
Giardia muris (hamsters)
- histo findings
- pear-shaped to ellipsoidal trophozoites in crypts of duodenum (will cover brush borders of enterocytes and entire intestinal tract and colon in clinical cases)
- lamina propria infiltrated by lymphocytes and plasma cells
Best stain for visualizing giardia muris
Giemsa
What is the pinworm of the hamster
Syphacia mesocricetus
- broad cervical alae, ending halfway to esophageal bulb (round)
- long, pointed tail
Clinical signs of syphacia mesocricetus
subclinical
Where does Trichosomoides nasalis typically infect
- nasal cavity
- larvae within muscle cells
Where do trichosomoides males like to live
within the uterus of the female worm
ID the four tapeworms of hamsters
- Taenia taeniaeformis
- Hymenolepis diminuta
- Rodentolepis nana
- Rodentolepis microstoma
Which hamster tapeworm can complete a direct life cycle in hamsters and gerbils?
Rodentolepis nana
Locations of tapeworm infections
- H. diminuta is in upper small intestine
- Rodentolepis spp. are in lower small intestine
Differentiate H. diminuta vs. R. nana
H. diminuta
- adults: prominent alae, no rostellar hooks present on scolex
- eggs: yellowish, spherical, no hooks or filaments
R. nana
- adults: armed rostellum
- eggs: 3 pairs of polar filaments; 2 membranes
What are the two demodex mites of hamsters
Demodex aurati and demodex criceti
Shape of D. aurati and D. criceti
Where are the preferred locations of D. aurati and D. criceti
D. aurati
- long, more cigar-shaped, typical demodex appearance
- deeper in the hair follicles
D. criceti
- bullet-shaped, 4 pairs of short, stubby legs, no setae, blunt posterior
- edge of affected lesions, more superficial than D. aurati
Demodicosis in hamsters
1. predisposing factors
2. gross findings
3. histopath findings
- aged or immunodeficient hamsters; high parasite load in MALE hamsters
- scaling and alopecia over back, neck, and hindquarters
- hair follicles dilated and filled with mites and debris, minimal inflammation
What is one of the cauasative agents of mange in hamsters?
what are the clinical signs
- Notoedres muris; others are Notoedres cati, Notoedres notoedres
- proliferative crusts on nose, feet, perianal areas, and ears
What other mites can hamsters be host to?
- Ornithonyssus bacoti (the tropical rat mite)
- ornithonyssus sylvarium (northern fowl mite)
