The three suborders of the order Rodentia are:
- Sciuromorpha - squirrels
- Myomorpha - mice, rats, gerbils, hamsters, lemmings and voles
- Hystricomorpha - chinchillas, degus, guinea pigs
- Which Family are guinea pigs in?
- Caviidae
How many digits do Guinea Pigs have?
4 digits on front feet
3 on their back feet.
What kind of teeth do Guiena Pigs have?
hypsodontic
What type of epithelium does the guinea pig stomach have?
Glandular epithelium only
What is the approximate gut transit time for guinea pigs?
20 hours
With coprophagy, that gut transit time can be extended to ___________.
60 to 70 hours
What are the two names for the reflex involving the “cocking” of the pinna in response to a sharp sound?
Preyer or pinna reflex.
What is the effect of ypophysectomy on growth rate of guinea pigs.
None. Pituitary gland does influence growth rate.
Guinea pigs, along with what two other non-rodent species, are strict herbivores and cecal fermenters?
Rabbits and horses
What is the primary fatty acid produced by fermentation in the guinea pig gut?
Propionic acid
How are young guinea pigs inoculated with autochthonous flora?
Ingestion of maternal feces
True or false. Guinea pigs have an os penis.
True
At about what time does the pubic symphysis separate in the female during gestation? What hormone is responsible for this separation?
last week of gestation
relaxin
Approximately how far does the pubic symphysis separate?
2.5-3 cm
What is the average litter size of guinea pigs?
5
Intensively bred sows develop what type of skin problem?
hair loss
What placenta type do guinea pigs have?
labyrinthine hemomonochorionic
Guinea pig young are precocious or altricious?
Precocious
Below which weight is survival of a newborn doubtful?
60 grams
Name four species for which Bordetella bronchiseptica is a commensal organism.
Rabbits, dogs, primates, rats, mice, swine, cats, turkeys
Definitive diagnosis of B. bronchiseptica occurs through aerobic culture of the organism on which two media?
Sheep’s blood and MacConkey’s agar
Reservoir for Streptobaccillis moniliformis?
wild rats
What are the two serovars for Streptococcus pneumoniae in guinea pigs?
4 and 19 F
True or false. Streptococcus pneumoniae is zoonotic.
True
In guinea pigs, salmonellosis usually results in enlargement of which two organs?
Liver and spleen
True or false. Yersinia pseudotuberculosis is associated with an acute, highly fatal septicemia as well as chronic emaciation in guinea pigs.
True
Clostridium difficile produces what exotoxins?
A and B exotoxins - bind to receptors on epithelial cells
Describe the enzyme immunoassay is available for identification of C. difficile toxin.
Detects exotoxin A in feces
Guinea pigs are susceptible to both human and bovine strains of _______________.
Mycobacterium
- were historically used as a diagnostic aide
- spontaneous cases very rare
- transmission os disease from humans or cattle is unlikely
The organism most likely found in cases of bumblefoot is ________________. What other pathologic lesions are associated with chronic cases?
Staphylococcus aureus
- chronic cases associated with amyloid in liver, adrenals, spleen, and pancreatic islets
In the guinea pig, where do Chlamydophila multiply?
Conjunctival epithelial cell cytoplasm
- Chlamydophila caviae
- intracytoplasmic inclusions
- 4-8 week old
Guinea pigs infected with Chlamydophila caviae make good models for which two types of human infections of Chlamydophila?
Conjunctival and genital
Describe herpesviral infection in guinea pigs
- Guinea Pig Cytomegalovirus – GPCMV
- usually subclinical, or weight loss, lymphadenopathy
- Hartley guinea pigs more suceptible than strain 2
- large, eosinophilic, uusually intranuclear inclusion bodies in ductal epitheliam cells of submaxillary salivary gland 5 days-3 weeks after exposure
- inclusion bodies may also be in brain, lung, kidney, spleen, pancreas, thymus, liver
What the two herpes like viruses found in guinea pigs that are not primary pathogens but may complicate research?
- Guinea Pig Herpes Like Virus (GPHLV) - from primary guinea pig kidney cell cultures
- Guinea Pig X Virus (GPXV) - from leukocytes of strain 2 guinea pigs
Which virus should be included on a differential diagnosis list for lameness?
Poliovirus
- RNA enterovirus
- some antigenic cross-reaction with GDVII strain of mouse poliovirus
- depression, lameness in one or more limbs, flaccid paralysis, weight loss, death over 2 weeks
- diagnosis by positive ELISA using TMEV/strain GDVII mouse virus antigen combined with histopath of CNS and lumbar spinal cord lesions
A “wasting syndrome” in guinea pigs characterized by anorexia, severe eweight loss, diarrhea, and high mortality. Grossly, intestinal segments are reddened. Histologically, there is epithelial loss at the tips of the villi. What is your top differential and how would you definitively diagnose?
Coronavirus-like Particle (CVLP)
- definitive diagnosis by detecting particle in feces by electron microscopy, histologic signs, and exclusion of other protozoal and bacterial enteropathies
Eimeria caviae is often seen as a co-infection with what organism?
Balantidium coli
What disease is a primary risk for guinea pigs if exposed to rabbit urine?
Ecephalitozoon cuniculi
- affects canids, rabbits, rats, mice, NHPs, guinea pigs, and other species
- guinea pigs resistant to large spore doses, and disease does not usually cause clinical disease
Which protozoal disease is usually concomitant with an Escherichia coli enterotoxemia?
Cryptosporidium wruiri
- coccidia of guinea pigs
- usually subclinical
- clinical signs most aften seen in young (< 300g or < 16 weeks)
- prepatent period is 2 weeks, and infection usually cleared by 3-4 weeks post-ingestion
True or false. Balantidium caviae is non pathogenic.
True
Klossiella cobayae has a predilection for which internal organ?
Kidney
Found on fecal floatation of feces from a guinea pig.
Paraspidodera uncinata
- cecal worm and only common helminth of the guinea pig
- eggs seen in feces
- inhabits but does not penetrate cecal and colonic mucosa
- worms mature in 45 days, life cycle 51-66 days
- infectious 3-5 days after shedding
What ascarid carried by raccoons an infect guinea pigs?
Baylisascaris proyonis
- ova remain viable for years in soil, and weeks to months in straw
- eggs resistant to most chemical disinfectants
- ZOONOTIC
- migration of larvae in CNS cause progressive neurologic disease: torticollis, ataxia, anorexia, stupor, hyperexcitability
Name and describe the mites which infest guinea pigs.
Chirodiscoides caviae
- usually asymptomatic
- heavy infectations can be seen on hair shafts
Trixacarus caviae
- intensely pruritic
- severely affected animals self-mutilate, lose weight, run, bump into objects, convulse and die
- ZOONOTIC
- T. caviae may result in a ____________________________ pyoderma.
- Staphylococcal
- The zoonotic lesions caused in people by T. caviae are transient, pruritic _______________ lesions.
- Papulovesicular
- Guinea pigs have (chose one) biting/chewing or sucking lice.
- Guinea pigs only have biting/chewing lice
- Of the two species of lice affecting guinea pigs (Gyropus ovalis and Gliricola porcelli), which one is more common?
- Gliricola porcelli
- True or false. Lice can be found macroscopically.
- True
- What is the approximate length of a guinea pig louse?
- 1 to 1.5 mm
- Where is pediculosis most evident in guinea pigs?
- Around the ears and the nape of the neck
- Guinea pigs contract lice through direct contact with an infected guinea pig and contaminated________________.
- Bedding
- What injectable drug is efficacious in treating pediculosis?
- Ivermectin
- What two flea species have been known to affect guinea pigs?
- Ctenocephalides felis (cat flea) and Nosopsyllus fasciatus (rat flea)
- The two main genera of causative fungi for dermatophytosis in guinea pigs is the zoophilic ________________ and the saprophytic _________________.
- Tricophyton is zoophilic and Microsporum is saprophytic.
- Where is dermatophytosis most evident on a guinea pig?
- Around the eyes, nose, and beneath both ears
- Does the hair lost during dermatophytosis regrow?
- Yes
- The vesicles, pustules, and abscesses seen in dermatophytosis are most likely from a _______________ ______________ infection.
- Secondary bacteria
- True or false. Dermatophytosis is exceptionally pruritic in guinea pigs.
- False. Dermatophytosis is usually non-pruritic in guinea pigs.
- The incubation period for dermatophytosis in guinea pigs is how many days (a range)?
- 9 to 12
- The dermatophytes infect which layers of keratin in the skin?
- Stratum corneum
- The most reliable diagnostic method for dermatophytosis is culturing. How long does this usually take?
- 10 days
- Two very common causes of hypovitaminosis C are_______________________________ and ______________________________.
- Feeding out of date food and feeding food meant for other species (especially rabbit food)
- What two conditions should alert the clinical as to the possibility of a “marginal” vitamin C deficiency.
- Conjunctivitis and upper respiratory disease
- Give two other names for hypovitaminosis C.
- Scurvy and scorbutus
- Guinea pigs lack the genetic code to produce which hepatic enzyme, resulting in the need of guinea pigs to have vitamin C enriched foods?
L-gulonolactone oxidase
- Vitamin C is a cofactor in which two types of reactions?
- Hydroxylation and amidation reactions
- What are the two molecule types that when not scavenged intra and extracellulary by vitamin C result in tissue damage?
- Singlet oxygen and superoxide radicals
- The primary problem of having marginally vitamin C deficient guinea pigs in a research environment is________________________________________.
- Increased susceptibility to infectious diseases
- Name at least three other types of animals that are not able to produce their own Vitamin C.
- Primates, fruit eating bats, some birds, some fish, some cetaceans
- At necropsy, Vitamin C deficient animals have bleeding in the subperiosteum, adrenal ______________, _________________muscle, joints, and intestines.
- Adrenal cortex and skeletal muscle
- What two elements are missing in the connective tissue of animal suffering from hypovitaminosis C?
- Hydroxylysine and hydroxyproline
- The normal serum level of Vitamin C in guinea pigs is round _______ mg/dl.
- 2.01 mg/dl
- True or false. Guinea pigs need to ingest approximately 6 mg of Vitamin C a day.
- True
- Guinea pigs drinking alcohol have a (chose one) increased or decreased need for Vitamin C?
- Increased
- The two types of pregnancy toxemia seen are broadly described as ______________ and _______________.
- Circulatory and Nutritional
- What other animals (name three) also suffer from pregnancy toxemia similar to guinea pigs?
- Primates, rabbits, ruminants, dogs
- Which type (see question 91) of pregnancy toxemia usually results in more severe changes seen at necropsy?
- Circulatory
- In both forms, the liver is affected. Briefly describe the liver changes seen macroscopically.
- Enlarged and yellow tan in color. Necrotic foci seen with the circulatory form
- Ketosis can cause what pathological changes in the stomach?
- Gastric ulceration
- The proteinaceous urethral plugs found in older male guinea pigs probably originate from which accessory sex organ?
- Seminal vesicles
- True or false. The two primary bacteria involved in cystitis in guinea pigs are Escherichia coli and Staphylococcus sps.
- True
- Urolithiasis is common in (chose one) young/middle age/older (chose one) boars/sows.
- Older Sows
- Continued occlusion of urinary output by urinary calculi may result in hydro-______________ and hydro-______________.
- Hydroureter and Hydronephrosis
- The progression of formation for uroliths in guinea pigs is ionic saturation to _______________ to nucleation to ________________ to crystal growth in urolith formation.
- Ionic saturation to supersaturation to nucleation to crystallization to crystal growth in urolith formation
- The limiting amino acid of guinea pigs is _______________.
- Arginine
- Diets deficient in tryptophan lead to the formation of what ocular problem in guinea pigs?
- Cataracts
- Guinea pigs synthesize enough Vitamin ______ and most of the _______ Vitamins.
- Guinea pigs synthesize enough Vitamin K and most of the B Vitamins
- A diet deficient in Thiamin (Vitamin B1) leads to what types of clinical signs?
- Central nervous system clinical signs
- A diet deficient in Riboflavin (Vitamin B2) results in what type of ocular lesion?
- Corneal vascularization
- Potassium is known in guinea pigs to counteract the adverse effects of excess __________ by providing an exchange cation to remove excess _____________ ions.
- Phosphate, Hydrogen
- True or false. Multifocal mineralization of skeletal and cardiac muscle fibers in guinea pigs over 1 year of age are usually life threatening.
- False. The Multifocal mineralization is usually asymptomatic.
- What is a primary reason to not feed food meant for other species to guinea pigs?
- To prevent metastatic calcification and mineralization
- Diabetes mellitus in guinea pigs resembles Type ______ diabetes in humans.
- Type I
- Guinea pigs injected subcutaneoulsy with Freund’s complete adjuvant (FCA) are known to develop what type of respiratory tract lesions?
- Pulmonary granulomas
- Hair loss is frequently observed in intensively bred sows. Does the hair regrow when breeding ceases?
- Yes
- True or false. A transient hair loss can be noted in young guinea pigs at weaning.
- True
- A fetus larger than _______ grams can be a cause of dystocia in guinea pigs.
- 100 grams
- Sows should be bred before _______ months of age to allow for the pubic symphysis to properly separate in the last part of gestation.
- 7
- Cavian leukemia is ______-cell neoplasm. The primary cell type seen is____________.
- B-cell neoplasm, Lymphoblast
- True or false. The leukocyte count in cavian leukemia never reaches more than 100,000/mm3.
- False. The counts can go as high as 250,000/mm3
- What types of tumors are the most frequent in guinea pigs?
- Hemolymphopoietic
- The most common skin tumor of guinea pigs is the _____________________. What is the recommended treatment for this tumor type and where is it usually seen?
- Trichofolliculoma, surgical removal is the recommended course of treatment
- Cutaneous papillomas are most often seen where in a guinea pig?
- Foot pads
- True or false. Testicular tumors are relatively common in guinea pigs.
- False. Testicular tumors are rare in guinea pigs
- The mammary adenocarcinomas seen in guinea pigs are of ____________ origin and will frequently metastasize.
- Ductal
- Root abscesses of the upper molar teeth may extend into the _____________ sinus and result in what type of ocular lesion?
- Maxillary, Exophthalmos
- In guinea pig molar occlusions, the points from the maxillary teeth usually point __________ and the points from the mandibular teeth usually point ____________.
- Labially, Lingually
- Deposition of amyloid in what four organs is commonly seen in aged guinea pigs or guinea pigs suffering from chronic inflammation?
- Kidneys, adrenals, liver, spleen
- What is amyloid?
- Amyloid is the extracellular deposition of polymerized protein subunits.
- What is the range of incidence of cystic ovaries at necropsy in older sows?
- 76 to 90%
- True or false. Cystic ovaries are never associated with leiomyomas of the uterine body or horns.
- False. Cystic ovaries are associated with leiomyomas of both the uterine body and horns.
- Does the large foci of adipose tissue found spaced amount normal, functional pancreatic tissue of older guinea pigs interfere with pancreatic function?
- No
- Guinea pigs have what type of retina?
- Paurangiotic
- True or false. Guinea pigs have no tapetum.
- True
- Genetic cataracts, found in strain __________ guinea pigs, are from a single, autosomal gene depletion of 34 residues that production a novel ξ-crystalline lens protein
- 13/N
what are Kurloff cells?
estradiol-dependent mononuclear leukocyte unique to
the guinea pig, with a large mucopolysaccharide, intracytoplasmic inclusion body and NK activity in vitro