Biology, Husbandry Biology, Husbandry and Diseases of the and Diseases of the

Guinea PigGuinea PigVCM 656VCM 656

Rodent SubordersRodent Suborders

HYSTRICOMORPHA(porcupine-like)

SCIUROMORPHA(squirrel-like)

MYOMORPHA(rat & mouse-like)

Guinea Pig Squirrel Rat

Chinchilla Chipmunk Mouse

Porcupine Beaver Hamster

Capybara Gopher Gerbil

Cavia porcellusCavia porcellusCommon names:Common names:

Guinea PigGuinea Pig

CavyCavy

English or shorthair

Peruvian

nude

Abyssinian

Research UsesResearch Uses

ImmunologyImmunology

Complement and red blood cell donors Complement and red blood cell donors for diagnostic testingfor diagnostic testing

Respiratory anaphylaxisRespiratory anaphylaxis

Airway researchAirway research

DentitionDentition I 1/1, C 0/0, P 1/1, M 3/3I 1/1, C 0/0, P 1/1, M 3/3 All teeth grow continuouslyAll teeth grow continuously Malocclusion of molars and premolars is Malocclusion of molars and premolars is

commoncommon

MalocclusionMalocclusion Usually involves premolars Usually involves premolars

and molarsand molars Clinical signs include:Clinical signs include:

Weight loss, excessive Weight loss, excessive salivation, tongue traumasalivation, tongue trauma

Treatment involves periodic Treatment involves periodic trimmingtrimming

Incisor overgrowth is Incisor overgrowth is usually secondary to usually secondary to premolar/molar overgrowthpremolar/molar overgrowth

GI TractGI Tract

Fully glandular stomachFully glandular stomach

Large cecumLarge cecum

FeetFeet

External genitaliaExternal genitalia Single pair of inguinal nipplesSingle pair of inguinal nipples

Extrude penisExtrude penis

Normal ParametersNormal Parameters

Adult body weight:Adult body weight: male 900-1200 male 900-1200 gg

female 700-900 female 700-900 gg

Life span:Life span: 3-7 years3-7 years Rectal temperature:Rectal temperature:100.2-103.1100.2-103.1ooFF First estrus:First estrus: 68 days68 days Estrus cycle:Estrus cycle: 15-17 days15-17 days Gestation:Gestation: 63 days average63 days average Fertile:Fertile: 4-5 years4-5 years

Kurloff CellKurloff Cell

Specialized natural killer cellSpecialized natural killer cell Large mucopolysaccharide intracytoplasmic inclusionLarge mucopolysaccharide intracytoplasmic inclusion Population shifts from lungs and spleen to thymus and Population shifts from lungs and spleen to thymus and

placenta during pregnancyplacenta during pregnancy Unknown functionUnknown function

NutritionNutrition

Requires Vitamin C in the diet.Requires Vitamin C in the diet. Use commercial diets within 90 days of millingUse commercial diets within 90 days of milling Cabbage and kale are high in vitamin CCabbage and kale are high in vitamin C Vitamin C in water must be changed dailyVitamin C in water must be changed daily

Do not feed antibiotic containing dietsDo not feed antibiotic containing diets Picky eatersPicky eaters

Very reluctant to eat new feedsVery reluctant to eat new feeds Begin to discriminate between food and Begin to discriminate between food and

nonfood within a few days of birthnonfood within a few days of birth Introduce experimental feeds early and Introduce experimental feeds early and

graduallygradually

Vitamin C DeficiencyVitamin C DeficiencyScurvy, ScorbutismScurvy, Scorbutism

GP’s are L-gluonolactone oxidase deficientGP’s are L-gluonolactone oxidase deficient Necessary for conversion of glucose to Necessary for conversion of glucose to

ascorbic acidascorbic acid Causes defective formation of collagen, Causes defective formation of collagen,

osteoid, dentinosteoid, dentin Clinical signs:Clinical signs:

Swollen, painful jointsSwollen, painful joints Reluctance to moveReluctance to move Delayed wound healingDelayed wound healing HemorrhagesHemorrhages Impaired bone/teeth formationImpaired bone/teeth formation DeathDeath

Vitamin C DeficiencyVitamin C Deficiency

HistologyHistology Disruption of Disruption of

epiphyseal cartilage epiphyseal cartilage and new bone and new bone spiculesspicules

Bone marrow fibrosisBone marrow fibrosis

Vitamin C DeficiencyVitamin C Deficiency

Prevention Prevention Daily vitamin C Daily vitamin C

sourcesource 10 mg/kg10 mg/kg 30 mg/kg – 30 mg/kg –

pregnant sowspregnant sows

TreatmentTreatment > 50 mg/kg daily> 50 mg/kg daily Injection vs. oralInjection vs. oral Continue until Continue until

improvement is improvement is seenseen

Sources of Vitamin CSources of Vitamin C Fresh, commercial Fresh, commercial

dietdiet Cabbage or kaleCabbage or kale Oranges or green Oranges or green

pepperpepper Ascorbic acid in Ascorbic acid in

waterwater 200-400 mg/l200-400 mg/l Prepare dailyPrepare daily

Metastatic CalcificationMetastatic Calcification Common in pigs over one yearCommon in pigs over one year Usually incidental necropsy findingUsually incidental necropsy finding Typically no clinical signsTypically no clinical signs

+/- muscle stiffness+/- muscle stiffness +- renal malfunction+- renal malfunction

Widespread tissue mineralizationWidespread tissue mineralization Kidney, stomach, heartKidney, stomach, heart Liver, uterus, colon, etc.Liver, uterus, colon, etc.

Possible diet connectionPossible diet connection Can induce by feeding:Can induce by feeding:

Excessive phosphorus orExcessive phosphorus or Excessive magnesiumExcessive magnesium

BehaviorsBehaviors

Freeze ReactionFreeze Reaction Tonic immobility following noise, shock or Tonic immobility following noise, shock or

environmental changeenvironmental change May last 20 minutesMay last 20 minutes

Scatter ReactionScatter Reaction Scatter in all directions, stampeding, Scatter in all directions, stampeding,

running in circles, trampling youngrunning in circles, trampling young Response to sudden movement or noiseResponse to sudden movement or noise

Preyer or Pinna ReflexPreyer or Pinna Reflex Cocking of ear in response to sharp soundCocking of ear in response to sharp sound Absence means hearing dysfunctionAbsence means hearing dysfunction Used in otologic researchUsed in otologic research

BreedingBreeding

First breeding:First breeding: 2-4 months2-4 months Estrus cycle:Estrus cycle: 15-17 days15-17 days Breeding life:Breeding life: 18-20 months18-20 months

MatingMating Courtship by boarCourtship by boar

Sniffing, circling, licking, nibbling, Sniffing, circling, licking, nibbling, mountingmounting

Lordosis by sowLordosis by sow 75-80% of matings are fertile75-80% of matings are fertile

Pending ParturitionPending Parturition Separation of pubic symphysis – 2 to 48 hoursSeparation of pubic symphysis – 2 to 48 hours

Palpate – 3 cmPalpate – 3 cm Dystocia is common if not first bred prior to 6 Dystocia is common if not first bred prior to 6

monthsmonths

DystociaDystocia Causes:Causes:

Incomplete relaxation of pubic symphysisIncomplete relaxation of pubic symphysis Large or malformed fetusLarge or malformed fetus Abnormal presentationAbnormal presentation Uterine inertiaUterine inertia Pregnancy toxemiaPregnancy toxemia

TherapyTherapy Oxytocin if pubic symphysis is separatedOxytocin if pubic symphysis is separated C-sectionC-section

PreventionPrevention First breed sows prior to 6 months of ageFirst breed sows prior to 6 months of age Avoid obesityAvoid obesity

Pregnancy ToxemiaPregnancy Toxemia

OccurrenceOccurrence Last 2 weeks of gestation / within Last 2 weeks of gestation / within

days of parturitiondays of parturition Pregnancy is not an essential factorPregnancy is not an essential factor

Predisposing factorsPredisposing factors Obesity and fastingObesity and fasting 11stst or 2 or 2ndnd pregnancy pregnancy Diet changeDiet change Nonspecific stressNonspecific stress

Known causesKnown causes Uteroplacental ischemiaUteroplacental ischemia

Aortic compression caudal to renal Aortic compression caudal to renal arteriesarteries

Placental degeneration and DICPlacental degeneration and DIC Fasting (anorexia) resulting in Fasting (anorexia) resulting in

ketosisketosis

Pregnancy ToxemiaPregnancy Toxemia

LesionsLesions Hemorrhage and necrosis at placental sites Hemorrhage and necrosis at placental sites ** Fatty changes in liver Fatty changes in liver ** Adrenal gland enlargement with hemorrhageAdrenal gland enlargement with hemorrhage Necrosis of renal proximal tubulesNecrosis of renal proximal tubules ProteinuriaProteinuria

Prevention is much more successful than treatmentPrevention is much more successful than treatment

MotheringMothering

Sows are not attentive mothersSows are not attentive mothers Neonates must nurse “on the run”Neonates must nurse “on the run” If not nursed for 24 hours, sows may not If not nursed for 24 hours, sows may not

return to nursingreturn to nursing Preweanings will nurse from different Preweanings will nurse from different

sows and strip milk needed for younger sows and strip milk needed for younger animals.animals.

YoungYoung Precocious youngPrecocious young

Walking, eyes open, teethWalking, eyes open, teeth Wean at 3-4 weeksWean at 3-4 weeks

Partial AlopeciaPartial Alopecia

SowsSows Late gestation – commonLate gestation – common Resolves following parturitionResolves following parturition

WeanlingsWeanlings Moth-eaten appearanceMoth-eaten appearance Guard hairs are emerging and undercoat is Guard hairs are emerging and undercoat is

thinningthinning BarberingBarbering

Dominance behavior in groupsDominance behavior in groups Self-barbering due to stressSelf-barbering due to stress

CagingCaging

Solid bottom with beddingSolid bottom with bedding

Wide slotted floors are OKWide slotted floors are OK

CagingCaging

GP’s are messyGP’s are messy Will defecate in food and Will defecate in food and

water crockswater crocks RecommendRecommend

Water bottles and J-feedersWater bottles and J-feeders

CagingCaging

PododermatitisPododermatitis

Causal factors:Causal factors: ObesityObesity Rough wire flooringRough wire flooring Poor husbandryPoor husbandry

Trauma predisposes to secondary bacterial Trauma predisposes to secondary bacterial infectionsinfections

Move to solid, clean environmentMove to solid, clean environment Local treatmentLocal treatment Crusty, painful lesions are slow to healCrusty, painful lesions are slow to heal

What could cause this What could cause this lesion?lesion?

Cage TraumaCage Trauma Young guinea pigsYoung guinea pigs Wire mesh floorsWire mesh floors Trapped foot plus Trapped foot plus

excitable animalexcitable animal Flesh wounds and/or Flesh wounds and/or

fracturesfractures

HandlingHandling

InjectionsInjections

Blood CollectionBlood Collection

Injection / Blood CollectionInjection / Blood Collection

Injection / Blood CollectionInjection / Blood Collection

Bordetella Bordetella bronchisepticabronchiseptica

Gram negative aerobeGram negative aerobe Epizootic pneumonia with high Epizootic pneumonia with high

mortalitymortality Sporadic deaths, more often in winterSporadic deaths, more often in winter Clinical signsClinical signs

LethargyLethargy Rough hair coatRough hair coat Nasal dischargeNasal discharge SneezingSneezing Sudden deathSudden death

Bordetella bronchisepticaBordetella bronchiseptica

Otitis mediaOtitis media Torticollis (head Torticollis (head

tilt) if severetilt) if severe

RadiographRadiograph Tympanic bullaTympanic bulla

Bordetella bronchisepticaBordetella bronchiseptica

BronchopneumoniaBronchopneumonia Consolidated lungsConsolidated lungs Large accumulations of neutrophils and intraluminal Large accumulations of neutrophils and intraluminal

debrisdebris

Bordetella bronchisepticaBordetella bronchiseptica

TransmissionTransmission Direct contactDirect contact FomitesFomites AerosolAerosol

Rabbits are asymptomatic carriersRabbits are asymptomatic carriers Don’t house rabbits and guinea pigs Don’t house rabbits and guinea pigs

togethertogether Beware of traffic patternsBeware of traffic patterns

Prevention is more successful than Prevention is more successful than TreatmentTreatment

Cervical Lymphadenitis Cervical Lymphadenitis = = LumpsLumps

Streptococcus zooepidemicusStreptococcus zooepidemicus Clinical signsClinical signs

Suppurative or caseous lymph node abscessesSuppurative or caseous lymph node abscesses Bronchopneumonia, pyothorax, sepsis – less Bronchopneumonia, pyothorax, sepsis – less

commoncommon TransmissionTransmission

Direct contact or aerosolDirect contact or aerosol TreatmentTreatment

Surgical drainageSurgical drainage AntibioticsAntibiotics

Rabbits and other speciesRabbits and other species Asymptomatic carriersAsymptomatic carriers

Streptobacillus moniliformisStreptobacillus moniliformis can cause can cause similar lymph node lesionssimilar lymph node lesions

Streptococcus Streptococcus pneumoniaepneumoniae

Epizootic outbreaks with high mortalityEpizootic outbreaks with high mortality TransmissionTransmission

Asymptomatic carriers, including GP’s, rats and Asymptomatic carriers, including GP’s, rats and manman

Direct contactDirect contact Stress-inducedStress-induced Fibrinosuppurative lesionsFibrinosuppurative lesions

PneumoniaPneumonia PleuritisPleuritis PericarditisPericarditis PeritonitisPeritonitis

Antibiotic-Induced Antibiotic-Induced EnterotoxemiaEnterotoxemia

Hemorrhagic TyphlitisHemorrhagic Typhlitis Overgrowth of enterotoxin-producing enteric bacteria, Overgrowth of enterotoxin-producing enteric bacteria,

ex. ex. Clostridium difficileClostridium difficile Often follows antibiotic use, dietary changes, or stressOften follows antibiotic use, dietary changes, or stress Clinical signs:Clinical signs:

AnorexiaAnorexia Rapid weight lossRapid weight loss DehydrationDehydration DiarrheaDiarrhea DeathDeath

Antibiotic-Induced EnterotoxemiaAntibiotic-Induced Enterotoxemia

Enlarged cecum, filled with blood and gasEnlarged cecum, filled with blood and gas Loss of cecal epithelium, with extensive Loss of cecal epithelium, with extensive

hemorrhage and necrosis of mucosa and hemorrhage and necrosis of mucosa and submucosasubmucosa

Supportive treatment rarely effectiveSupportive treatment rarely effective Antibiotics to avoid: Penicillin, erythromycin, Antibiotics to avoid: Penicillin, erythromycin,

lincomycin, streptomycin, tetracycline, bacitracinlincomycin, streptomycin, tetracycline, bacitracin

SalmonellosisSalmonellosis S. typhimuriumS. typhimurium and and S. enteritidisS. enteritidis most most

commoncommon Transmission by contaminated food or Transmission by contaminated food or

waterwater Sporadic outbreaks with high morbidity & Sporadic outbreaks with high morbidity &

mortalitymortality Clinical signs:Clinical signs:

Rough hair coat, anorexia, weight loss, lethargyRough hair coat, anorexia, weight loss, lethargy Soft feces, but diarrhea is rareSoft feces, but diarrhea is rare

SalmonellosisSalmonellosis

Gross findingsGross findings Fluid and gas filled GI Fluid and gas filled GI

tracttract Liver and spleen Liver and spleen

enlargementenlargement Histological findingsHistological findings

Multifocal necrosisMultifocal necrosis Liver, spleen, Liver, spleen,

lymphatic tissuelymphatic tissue ControlControl

DepopulationDepopulation ZoonoticZoonotic

CryptosporidiumCryptosporidium sp sp Protozoan – major cause of enteric Protozoan – major cause of enteric

disease in GP’sdisease in GP’s Clinical signsClinical signs

Subclinical infections commonSubclinical infections common Lethargy, rough hair coat, weight loss, Lethargy, rough hair coat, weight loss,

diarrheadiarrhea ““Greasy coat” appearanceGreasy coat” appearance

TransmissionTransmission Contaminated food & waterContaminated food & water fomitesfomites

CryptosporidiumCryptosporidium sp sp

Colonize anterior ileumColonize anterior ileum Histologic lesionsHistologic lesions

Fusion, atrophy and metaplasia of villous Fusion, atrophy and metaplasia of villous epitheliumepithelium

Eosinophilic infiltration of lamina propriaEosinophilic infiltration of lamina propria DiagnosisDiagnosis

Identify organisms within:Identify organisms within: Epithelial cellsEpithelial cells Mucosal scrapingsMucosal scrapings Fresh fecal smearsFresh fecal smears Fecal floats don’t workFecal floats don’t work

No effective treatmentNo effective treatment Zoonotic potentialZoonotic potential

Lymphosarcoma Lymphosarcoma = Cavian = Cavian LeukemiaLeukemia

RetrovirusRetrovirus Type C OncornavirusType C Oncornavirus

Virus is widespreadVirus is widespread Transplacental Transplacental

transmissiontransmission Dormant until aged or Dormant until aged or

stressedstressed Lymphoblastic cell Lymphoblastic cell

infiltrationinfiltration Liver, spleen lymph Liver, spleen lymph

nodesnodes

DermatophytosisDermatophytosis

Trichophyton mentagrophytesTrichophyton mentagrophytes Asymptomatic carriers are commonAsymptomatic carriers are common Griseofulvin is effectiveGriseofulvin is effective

AcariasisAcariasis Primarily 2 mite species infect Primarily 2 mite species infect

GP’sGP’s Trixacaris caviaeTrixacaris caviae – burrowing mite – burrowing mite

Neck, shoulders, abdomen inner Neck, shoulders, abdomen inner thighsthighs

Alopecia, crusting, intense Alopecia, crusting, intense pruritispruritis

Self mutilation, debility, deathSelf mutilation, debility, death Chirodiscoides caviaeChirodiscoides caviae - fur mite - fur mite

Few to no clinical signsFew to no clinical signs

AcariasisAcariasis

Chirodiscoides caviae

Trixacaris caviae

LiceLice Chewing liceChewing lice Occasional alopecia and Occasional alopecia and

mild pruritismild pruritis Spread by direct contactSpread by direct contact Nits on hair shaftNits on hair shaft

Gyropus ovalis

Gliricola porcelliis

Lymphocytic Lymphocytic Choriomeningitis (LCM)Choriomeningitis (LCM)

RNA ArenavirusRNA Arenavirus Experimental infections onlyExperimental infections only Clinical signs:Clinical signs:

AsymptomaticAsymptomatic Rear limb paralysisRear limb paralysis CNS disturbancesCNS disturbances

EradicationEradication Colony depopulationColony depopulation