Parasites of Mice Flashcards
Which lab animal species are susceptible to Giardia muris?
Rats, mice, hamsters, and other rodents
What are the clinical signs of Giardia muris?
- often subclinical
- (with heavy infestation): decreased weight, distended abdomen, sluggish movement, rough hair cout
- immunodeficient mice may die during heavy infestation
T/F Giardia causes diarrhea in rodents.
False, it usually doesn’t
What is the treatment for Giardia muris
metronidazole in drinking water
Transmission of Giardia muris
fecal-oral
Susceptibility of G. muris
- Susceptible: C3H/He***
- Resistant: BALB/c C57BL/6
females < males (possibly due to more potent humoral response in females)
Gross lesions of G. muris
yellow or white watery fluid in intestines
Histopath of G. muris
- often adhered to microvilli of enterocytes or residing in mucosal crevices / mucus
- may see crypt:villus ratio reduced
- increased # of inflammatory cells within lamina propria
Diagnosis of G. Muris
- ID of trophozoite in sm. intestine or on fecal wet mounts (characteristic rolling and tumbling movements)
- Serology
- PCR
G. muris prevention
- proper sanitation and management, adequate disinfection of infected rooms
Research complications of G. muris
- accelerated cryptal cell turnover
- suppressed immune response to sheep erythrocytes
- severe/lethal infection previously noted
Where does Spironucleus muris like to reside
- duodenum, typically in crypts of Lieberkuhn or in intervillous spaces
Clinical signs of S. muris
- subclinical in normal mice
- more pathogenic in young/stressed/immunocompromised mice
— CLINICALLY EVIDENT infection more likely at 3-6 wks of age (dehydration, weight loss, poor hair coat, hunched posture, abdominal distention, diarrhea, +/- death
Typically more of a 2° issue than a 1° disease
Transmission of S. muris
fecal-oral
cross-infection possible between mice and hamsters, not rats though
Gross lesions of S. muris
watery, red-brown gaseous intestinal contents (not pathognomonic)
Histopath lesions of S. muris
- distention of crypts and intervillous spaces; inflammatory edema of lamina propria
What is a good stain to help visualize organisms between enterocytes in the lamina propria?
Acid-Schiff staining
Diagnosis of S. muris
- ID of trophozoites in GI tract
- differentiate from G. muris by smaller size, horizontal/zigzag movements, and absence of suckling disk or undulating membrane
Treatment of S. muris
metronidazole in drinking water
Research complications of S. muris
- can accelerate enterocytic turnover in small intestine
T/F: Tritrichomonas muris is pathogenic and will show clinical signs
False; it is nonpathogenic and will show no clinical signs, not even inflammation or necrosis
Preferred tissues of Eimeria falciformis
epithelial cells of large intestine
clinical signs of Eimeria falciformis
- diarrhea and catarrhal enteritis with heavy infections
What organism causes renal coccidiosis in wild mice
Klossiella muris
Gross lesions of Klossiella muris
Gray spots in heavily-affected kidneys
histopathology of Klossiela muris
- necrosis, granulomatous inflammation, and focal hyperplasia
- destruction of tubular epithelium may impair renal physiology
List three non-pathogenic protozoans
- Entamoeba muris
- Cryptosporidium parvum
- Cryptosporidium muris
What is a microsporidian that causes interstitial nephritis in rabbits and no clinical signs in mice?
Encephalitozoon cuninculi
What is a useful stain to detect E. cuniculi
Goodpasture stains
Also Giemsa
Big concern of E. cuniculi
zoonotic
Diagnosis of E. cuniculi
- Cytology of ascitic fluid smears
- Histopath of brain w/ Goodpasture stain
- ELISA serology
- PCR assay may be useful
What chain of events have to occur for Toxoplasma gondii or Sarcocystis muris to enter a vivarium
exposure to cat feces
Which mouse strain can serve as the definitive host of Sarcocystis muris?
SCID mice
T/F Toxoplasma gondii is gram-positive
False; it is gram-negative
What are the two pinworms of note in mice
- Syphacia obvelata
- Aspiculuris tetraptera
How can you differentiate the two pinworms of note in mice?
- Syphacia obvelata: round esophageal bulb, eggs are flattened on one side w/ pointy ends (banana-shaped)
- Aspiculuris tetraptera: elongated esophageal bulb; have four alae on head; eggs are bilaterally symmetic and ellipsoidal
S. obvelata adults migrate to the ____ and deposit their eggs _____, while A. tetraptera adults lay their eggs ___. _______ eggs can be found on tape tests, while _____ cannot.
- rectum
- on perianal tissue
- in the GI tract
- S. obvelata
- A.tetraptera
Clinical signs of pinworm infestation
- usually subclinical
- if heavy burden: rectal prolapse, intussusception, enteritis, fecal impaction
What is the term for louse infestation
Pediculosis
What disease does Polyplax serrata historically transmit in lab mice?
Mycoplasma coccoides
What is the term for fur mite infestations
Acariasis
How would you know if a mouse with acariasis is alive or dead?
the mites move to the tips of the hair shafts to get away from the cooling carcass if the mouse is dead
What do you need to know about your mice if you’re planning to treat them with ivermectin for mite infestation
Need to know if they are a strain with a leaky BBB, as Ivermectin easily crosses the BBB of those strains and can kill them
What is the most common ectoparasite of lab mice?
Mycoptes musculinis
What is the most clinically significant ectoparasite of mice? Why?
- Myobia musculi
- feeds on skin secretions and interstitial fluids, which can incite hypersensitivity dermatitis, esp. in C57BL/6 mice
Differentiate the three fur mites of mice
- Mycopties musculinis has a more chitinous exterior and ovular/round body
- Myobia musculi has single-clawed 2nd pair of legs and is more elongated
- Radfordia affinis has two unequal claws on 2nd pair of legs and is more elongated
What two mites infest the hair follicles of mice?
- Demodex musculi
- Psorergates simplex
What are the two tapeworms of note in mice
- Rodentolepis nana
- Hymenolepis diminuta
- What is the larval form of Taenia taeniformis and where can it be found in rats, mice, and hamsters
Cysticercus fasciolaris
in the liver
What is the source of Cysticercus infections
Cat feces (mice and rats are intermediate hosts)
T/F rodentolepis nana is zoonotic
true
Rodentolepis nana has which type of life cycle
both direct and indirect possible
How do you differentiate R. nana and H. diminuta eggs
- R. nana eggs has three pairs of hooklets (rostellar hooks) and prominent polar filaments
How do you differentiate R. nana and H. diminuta adults
- R. nana has hooks on rostellum
- H. diminuta has no rostellar hooks
