Biology, Husbandry and Diseases of the Guinea Pig VCM 656

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Biology, Husbandry and Diseases of the Guinea
PigVCM 656
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Rodent Suborders
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History and Origin

• Name not from a pig that lives in Guinea
• Native of South America

Habitat Grassland Forest Edges Swamps Rocky areas
Wild Guinea Pig found in Argentina, Brazil,
Paraguay, Peru, Columbia, Venezuela
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English or shorthair
Abyssinian
Peruvian
nude
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Coat Colors
Chocolate Dalmation
Black (English)
Tri-color
Roan
Agouti
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Regulations Animal Welfare Act
Defined together with the hamster. Temperatures
60 85oF Cannot house outside Exception
appropriate climate and approval from Deputy
officer of USDA Space same is guide but females
with litters 101 in2 Height 6.5 Primary
enclosure Solid with bedding Mesh to allow
feces but not feet or limbs
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Housing
Guinea Pig Cannot Tolerate over 90 oF

• Types
• Shoebox or other ideal
• Mesh floors
• 1.27 cm2 growing
• 1.6 cm2 breeding
• 1.27 X 5 cm to reduce injury
• Bedding
• Shavings
• Sawdust
• Risk of vaginitis and balanoposthitis
• Newspaper
• Straw

• Feeders
• Short snout (unlike rat)
• Rat slots too thin to
• reach food

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Caging

• Solid bottom with bedding
• Wide slotted floors are OK

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Caging

• GPs are messy
• Will defecate in food and water crocks
• Recommend
• Water bottles and J-feeders

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Caging
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Normal Parameters

• Adult body weight male 900-1200 g
• female 700-900 g
• Life span 3-7 years
• Rectal temperature 100.2-103.1oF
• First estrus 68 days
• Estrus cycle 15-17 days
• Gestation 63 days average
• Fertile 4-5 years

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Behavior

• Docile, gentle, lively
• Easy to handle
• Huddle in groups
• Move along edges

• Females
• No nest
• Little maternal instinct

• Vocalize
• Chirp (content)
• Scream in pain or distress

• Freeze or Flee
• Danger response

• Activity
• Active 20 hours a day
• Cannot jump

• Fastidious eaters
• Picky eater
• Established early in life

• Barbering
• Overcrowding
• Dominant male barber subordinates

• Poor food sanitation
• Defecate in food and water
• Supply in suspended feeder

Coprophagic Need for general health Fiber
digestion
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Cavidae Characteristics

• Identification
• Ear Notch
• Ear Tag
• Ear Tattoo
• Microchip
• Marker (temporary)

One pair mammary glands
Round, Hairless Pinnae Large tympanic bullae
(easy access)
Chromosomes 64
Rectal Temp. 37.2 39.5 oC 99 103. O F
Forelimb four digits Hindlimb three
digits One claw from each digit
Heart Rate 240 310 bpm
All teeth continually erupting
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Diastema (definition) Gap between incisors and
cheek teeth
Mandible articulates at Zygomatic Arch

• Salivary Glands
• Parotid
• Mandibular
• Sublingual
• Molar
• Ducts
• - Empty near molars

• Haircoat
• Large guard hairs
• Undercoat of hair

• No sweat glands
• Cannot shiver
• No undercoat

• Sebaceous glands
• On dorsum and around anus
• used for marking

Large tongue and narrow oral cavity Difficult
to intubate and/or oral gavage.
Lifespan around 5 6 years
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Oral Gavage

• Anatomy of the Oral Cavity
• Large Tongue
• Narrow oral cavity
• Diastema prevents access
• Free soft palate in continuous with the base of
  the tongue
• Oropharynx communicates with remnants of pharynx
  through hole
• Palatal Ostium

• MOLAR GROWTH
• Maxially teeth tend to grow
• medially.
• Entrapping Tongue

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Research Uses

• Anaphylaxis
• Asthma
• Gnotobiotics
• Immunology
• Infectious disease
• Nutritional disease
• Otology

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GI Tract

• Fully glandular stomach
• Mouth to cecum in 2 hours
• Large cecum
• located central/left side
• 15 cm long
• Thin-walled sac
• Lateral pouches formed by
• action of three taenia coli
• 65 capacity of entire GIT
• 10 of body weight
• GI flora gram anaerobic lactobacillus
• food in for 48 hours

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Sexing
? Castration Open inguinal canal Therefore,
must close tunic
Vaginal Closure Membrane Perforated during
parturition and breeding
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Kurloff Cell

• Specialized natural killer cell
• Large mucopolysaccharide intracytoplasmic
  inclusion
• Population shifts from lungs and spleen to thymus
  and placenta during pregnancy
• Unknown function

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Nutrition

• Requires Vitamin C in the diet
• Use commercial diets within 90 days of milling
• 5 (non-breeding) to 30(breeding) mg/kg/day
• 90 day shelf life for food
• 180 day shelf life with some food with stable
  Vitamin C
• Cabbage and kale are high in vitamin C
• Vitamin C in water must be changed daily
• Do not feed antibiotic containing diets
• Picky eaters
• Very reluctant to eat new feeds
• Begin to discriminate between food and nonfood
  within a few days of birth
• Introduce experimental feeds early and gradually

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Vitamin C DeficiencyScurvy, Scorbutism

• GPs are L-gluonolactone oxidase deficient
• Necessary for conversion of glucose to ascorbic
  acid
• Causes defective formation of collagen, osteoid,
  dentin
• Clinical signs
• Swollen, painful joints
• Reluctance to move
• Delayed wound healing
• Hemorrhages
• Impaired bone/teeth formation
• Death

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Vitamin C Deficiency

• Prevention
• Daily vitamin C source
• 10 mg/kg
• 30 mg/kg pregnant sows
• Treatment
• gt 50 mg/kg daily
• Injection vs. oral
• Continue until improvement is seen

• Sources of Vitamin C
• Fresh, commercial diet
• Cabbage or kale
• Oranges or green pepper
• Ascorbic acid in water
• 200-400 mg/L
• Prepare daily

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Metastatic Calcification

• Common in pigs over one year
• Usually incidental necropsy finding
• Typically no clinical signs
• /- muscle stiffness
• /- renal malfunction
• Widespread tissue mineralization
• Kidney, stomach, heart
• Liver, uterus, colon, etc.
• Possible diet connection
• Can induce by feeding
• Excessive phosphorus or
• Excessive magnesium

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Breeding Parturition
Wide Load Female can double in size

• Breeding Systems
• Monomogous
• Harem
• 1 boar w/3-4 sows
• Male left with harem (bred immediately
  post-partum) or
• Removed prior to parturition, returned after
  weaning
• Female
• 16 day cycle (13 21 days)
• Proestrus with increase activity and chasing
  cagemates
• 6-8 hours in estrus (estrual lordosis)
• Copulatory plug (several hours 24 hours post
  mating)
• 10 hour ovulation

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Parturition
1 Newborn cause of death Asphyxiation from
fetal membrane

• Pregnancy detection 15 days with 5mm swelling
• Gestation length Average 68 days (59 72)
• Parturition pubic symphysis separation
• (15mm 25mm)
• Parturition Day or Night
• Pups
• Litter size 1 4
• 45 115 gram birth weight
• function of litter size

• Newborns
• Precocious
• Mobile
• Fully furred
• Teeth erupted
• Eyes/ears open
• Eat solid food w/in few
• days
• Wean at 3-4 weeks

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Dystocia

• Causes
• Incomplete relaxation of pubic symphysis
• Large or malformed fetus
• Abnormal presentation
• Uterine inertia
• Pregnancy toxemia
• Therapy
• Oxytocin if pubic symphysis is separated
• C-section
• Prevention
• First breed sows prior to 6 months of age
• Avoid obesity

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Pregnancy Toxemia

• Occurrence
• Last 2 weeks of gestation / within days of
  parturition
• Predisposing factors
• Obesity and fasting
• 1st or 2nd pregnancy
• Diet change
• Nonspecific stress
• Known causes
• Uteroplacental ischemia
• Aortic compression caudal to renal arteries
• Placental degeneration and DIC
• Fasting (anorexia) resulting in ketosis

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Pregnancy Toxemia

• Lesions
• Hemorrhage and necrosis at placental sites
• Fatty changes in liver
• Adrenal gland enlargement with hemorrhage
• Necrosis of renal proximal tubules
• Proteinuria
• Prevention is much more successful than treatment

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Mothering

• Sows are not attentive mothers
• Neonates must nurse on the run
• If not nursed for 24 hours, sows may not return
  to nursing
• Preweanings will nurse from different sows and
  strip milk needed for younger animals.

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Partial Alopecia

• Sows
• Late gestation common
• Resolves following parturition
• Weanlings
• Moth-eaten appearance
• Guard hairs are emerging and undercoat is
  thinning
• Barbering
• Dominance behavior in groups
• Self-barbering due to stress

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Handling
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Injections
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Blood Collection
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Injection / Blood Collection
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Injection / Blood Collection
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Bordetella bronchiseptica

• Gram negative aerobe
• Epizootic pneumonia with high mortality
• Sporadic deaths, more often in winter
• Stress predisposes
• Clinical signs
• Lethargy
• Rough hair coat
• Nasal discharge
• Sneezing
• Sudden death

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Bordetella bronchiseptica

• Pathology
• Otitis media
• Torticollis (head tilt) if severe
• Rhinitis
• Tracheitits
• Bronchopneumonia

Radiograph Tympanic bullae
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Bordetella bronchiseptica

• Bronchopneumonia
• Consolidated lungs
• Large accumulations of neutrophils and
  intraluminal debris
• Pleural effusion

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Bordetella bronchiseptica

• Transmission
• Direct contact
• Fomites
• Aerosol
• Rabbits are asymptomatic carriers
• Dont house rabbits and guinea pigs together
• Beware of traffic patterns
• Prevention is more successful than treatment
• Antibiotics, fluids, force-feeding, vitamin C
  supplementation

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Cervical Lymphadenitis Lumps

• Streptococcus zooepidemicus
• Clinical signs
• Suppurative or caseous lymph node abscesses
• Bronchopneumonia, pyothorax, sepsis less common
• Transmission
• Direct contact or aerosol
• Treatment
• Surgical drainage
• Antibiotics
• Rabbits and other species
• Asymptomatic carriers
• Streptobacillus moniliformis can cause similar
  lymph node lesions

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Streptococcus pneumoniae

• Epizootic outbreaks with high mortality
• Transmission
• Asymptomatic carriers, including GPs, rats and
  man
• Direct contact
• Predisposition
• Stress
• Occurrence in winter
• Pregnancy
• Extreme temperatures
• Shipping (stress, temp. extremes)
• Poor diet
• Poor husbandry

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Streptococcus pneumoniae

• Clinical Signs
• Inactivity, rough hair, poor appetite
• Nasal discharge
• Pulmonary disease
• Dyspnea (most common sign)
• Females may abort
• Acute Death
• Pathology
• Conjuctivitis
  
• Otitis
• Abortion
• Fibrinosuppurative lesions
• Pneumonia
• Pleuritis
• Pericarditis
• Peritonitis
• Pulmonary abscesses

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Antibiotic-Induced EnterotoxemiaHemorrhagic
Typhlitis

• Overgrowth of enterotoxin-producing enteric
  bacteria, ex. Clostridium difficile
• Often follows antibiotic use, dietary changes, or
  stress
• Clinical signs
• Anorexia
• Rapid weight loss
• Dehydration
• Diarrhea
• Death

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Antibiotic-Induced Enterotoxemia

• Enlarged cecum, filled with blood and gas
• Loss of cecal epithelium, with extensive
  hemorrhage and necrosis of mucosa and submucosa
• Supportive treatment rarely effective
• Antibiotics to avoid Penicillin, erythromycin,
  lincomycin, streptomycin, tetracycline,
  bacitracin

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Salmonellosis

• S. typhimurium and S. enteritidis most common
• Transmission by contaminated food or water
• Sporadic outbreaks with high morbidity
  mortality
• Clinical signs
• Rough hair coat, anorexia, weight loss, lethargy
• Soft feces, but diarrhea is rare

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Salmonellosis

• Gross findings
• Fluid and gas filled GI tract
• Liver and spleen enlargement
• Histological findings
• Multifocal necrosis
• Liver, spleen, lymphatic tissue
• Control
• Depopulation
• Zoonotic

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Staphylococcus
AMYLOIDOSIS
Ishihara Disease Exfoliation skin disease
Osteoarthritis
PODODERMATITIS
S. aureus
Sore Hocks
Chronic Irritation
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Staphylococcus aureus

• Exfoliative skin disease (Ishihara)
• Pododermatitis
• Progresses to Osteroarthritis

• Exfoliative skin disease
• Young pigs born to affected dam

• Clinical Signs
• Alopecia, Erythema, Exfoliation

Day 2-3 Skin cracks in folds Skin
Flakes Exfoliation near cracks, then spreads over
entire VENTRAL body.
Chronic Staph. infections are associated with
amyloidosis of kidney, liver, spleen and adrenals.
Day 10-14 Onset of Healing
Lesions regress in about 2 weeks.
Mortality 0 Adults 88 Sucklings (mom painful)
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PododermatitisOsteoarthritis

• Predisposition
• 2 4 years old
• Obese
• Wire bottom cages
• Poor husbandry/sanitation
• Clinical Signs
• Feet erythematous
• Swelling
• Axillary lymphadenopathy
• Proliferative callous formation (macropodia)
• Staphylococcus sp. often isolated
• Treatment
• Weight control if obese
• Cleanse feet/topical antibiotic
• Better cage sanitation
• Improved flooring
• Provide bedding
• Provide a solid surface too if on wire bottom
• Provide dry area as much as possible

Consider Vitamin C deficiency as underlying and
correct.
Primarily the forefeet affected
Bumblefoot

• OSTEOARTHRITIS
• Can progress into O.A.
• Metacarpal and phalangeal joints
• Radiographs-- see
• bony proliferation and bone
• necrosis
• Systemic antibiotics

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Cryptosporidium sp

• Protozoan major cause of enteric disease in
  GPs
• Clinical signs
• Subclinical infections common
• Lethargy, rough hair coat, weight loss, diarrhea
• Greasy coat appearance
• Transmission
• Contaminated food water
• Fomites

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Cryptosporidium sp

• Colonize anterior ileum
• Histologic lesions
• Fusion, atrophy and metaplasia of villous
  epithelium
• Eosinophilic infiltration of lamina propria
• Diagnosis
• Identify organisms within
• Epithelial cells
• Mucosal scrapings
• Fresh fecal smears
• Fecal floats dont work
• No effective treatment
• Zoonotic potential

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Lymphosarcoma Cavian Leukemia

• Retrovirus
• Type C Oncornavirus
• Virus is widespread
• Transplacental transmission
• Dormant until aged or stressed
• Clinical Signs
• Rough hair coat
• Weight Loss
• Lymphadenopathy
• DDx for LUMPS

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Cavian Leukemia
Model for Viral Associated Neoplasia
Pathology -Leukocyte count 50,000
250,000/mm3 -Infiltration with lymphblastic
cells - Bone Marrow (Thrombocytopenia ) -
Spleen (Splenomegally) - Liver
(Hepatomegally) - Peyers Patch (weight loss)
- Lymphoblastic cell infiltration GPHLV
involvement?
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Adenovirus DNA virus

• ADENOVIRAL PNEUMONITIS
• Low morbidity but mortality high as 100
• Environmental stress triggers onset of syndrome
• Clinical signs
• Hunched posture
• Weight loss
• Rough hair coat
• Rapid labored breathing
• catarrhal exudate nose/front feet

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Adenovirus DNA virus

• Gross lesions
• Consolidation of cranial lung lobe
• Variable sized reddish (hemorrhage) foci in lung
• Histologically
• Sloughed epithelial cells occluding the lumen
  of bronchioles
• Infiltration of peribronchioloar stroma with
  lymphs,
• macrophages and a few PMN.
• Intranuclear inclusions are basophilic
• EM reveals classic arrays.

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Cytomegalovirus

• Salivary Gland Virus
• Herpes Virus
• Common in the Guinea Pig
• - Estimated some colonies
• 70-80 incidence

• Primary Infection
• Viremia
• (lung, spleen, kidney)
• Lasts ? 10 days
• Transplacental transmission
• - abortions, stillbirths, neonatal mortality

Primary Infection

• Chronic Persistent Infection
• High levels of serum AB
• Virus in Salivary gland and pancreas
• Occasional viremia

CLINICAL SIGNS Usually NONE
Chronic Infection
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Cytomegalovirus
Guinea Pig is a Model for Human CMV
Transplacental transmission
X
Mice Guinea Pig Man
CVM in many species, but host specific. In man is
important. Estimated 1 of neonates infected
with many causing CNS damage. Immunosuppressed
adults develop pneumonitis.
Model for Transplacental Acquired infection.
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Cytomegalovirus (CMV)

• Transmission
• Vertical
• - Transplacental
• Horizontal
• - Saliva
• - Urine
• - Conjunctiva
• - Blood
• - Sexual (? with opposite sex housing)

• Gross Pathology Usually none
• Histopatholgy
• eosinophilic intranuclear inclusion bodies in
• ductal epithelium of salivary glands
• the cells are 4 X size and bulge into lumen
• proximal and distal convoluted tubules of kidney
• margination of the nuclear chromatin

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Guinea Pig Herpes Like Virus
Model for Viral Associated Neoplasia

• Morphologically similar to CMV
• Has been isolated from many strains of Guinea
  Pigs, but
• Does not produce disease in the natural host
• Found in degenerating kidney cell culture
  (histologically)
• Causes intranuclear inclusion bodies

GPHLV
Relationship ?
CMV
Cavian Leukemia

• Incidence CMV ? ? GPHLV

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Lymphocytic Choriomeningitis Virus (LCMV)

• RNA Arenavirus
• Experimental infections only
• Clinical signs
• Asymptomatic
• Rear limb paralysis
• CNS disturbances
• Eradication
• Colony depopulation

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Dermatophytosis

• Trichophyton mentagrophytes
• Asymptomatic carriers are common
• Griseofulvin is effective

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Acariasis

• Primarily 2 mite species infect GPs
• Trixacarus caviae burrowing mite
• Neck, shoulders, abdomen inner thighs
• Alopecia, crusting, intense pruritis
• Self mutilation, debilitation, death
• Chirodiscoides caviae - fur mite
• Few to no clinical signs

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Acariasis
Trixacaris caviae
Chirodiscoides caviae
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Lice

• Chewing lice
• Occasional alopecia and mild pruritis
• Spread by direct contact
• Nits on hair shaft

Gyropus ovalis
Gliricola porcelliis