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Mouse Pox (ectromelia virus)
- * Enveloped DNA virus, largest, dumbbell shaped morphology.
- * Dry gangrene secondary to ischemic necrosis and vascular compromise of the extremities.
- * Also, rapidly fatal form multisystemic necrosis of the liver and spleen.
- * Characteristic large eosinophilic intracytoplasmic inclusion bodies in lesions.
- * Strains considered to be highly susceptible include A, BALB/c, C3H, DBA/1, and DBA/2.
- * Mouse is the only known host.
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Herpesvirus: Cytomegalovirus (MCMV), or, Murid herpesvirus (MuHV)1
- DNA
- * Mouse specific; Betaherpesvirus.
- * Megalocytosis containing eosinophilic intracytoplasmic or intranuclear inclusions, found usually in the salivary glands.
- * Resistant strains include B6, B10, CBA, and C3H mice. Susceptible strains include BALB/c and A strain mice.
- * MCMV latency can occur in macrophages, B lymphocytes, and reproductive tissues
- * Adult immunocompetent mice have an asymptomatic infection, but can be persistent. MCMV infection can cause multisystemic necrosis and inflammation in neonates.
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Herpesvirus: Mouse Thymic Virus (MTV), or, MuHV3.
- DNA
- * Betaherpesvirus
- * Natural infection is asymptomatic. Lesions develop only in mice infected perinatally. � Mice infected as infants or adults can develop a persistent infection.
- * Immunosuppressive, CD4 and CD8 T-Cells are selectively targeted.
- * Necrosis with associated intranuclear herpetic inclusions
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Parvovirus: Minute Virus of Mice - MVM; Mouse Parvovirus MPV1, MPV2, MPV3, MPV4, MPV5
- * Non-enveloped DNA virus, survives in the environment for extended time
- * Seldom clinical signs but difficult to eradicate. Most prevalent infectious agent in lab mouse
- * Induces cytologic disease only in dividing tissues.
- * Mouse is the only known host
- * MVM and MPV have 2 nonstructural proteins (NS-1 and NS-2) which are highly conserved and cross-reactive, and, 3 Viral Capsid Proteins (VP-1, VP-2, VP-3) that are non-conserved and may be used for individual identification (virus specific).
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Mouse Adenovirus (MAdV1, MAdV2)
- * Non-enveloped DNA viruses that replicate in nuclei. Large intranuclear inclusion bodies in intestinal epithelium.
- * There are two recognized strains: MAdV-1 (FL) is polytropic and may possibly be extinct (experimental infections). MAdV-2(K87) is strictly enterotropic.
- * Wasting disease in immunodeficient. Scruffiness, lethargy, and stunted growth (MAdV1). Runting in infant mice maybe (MAdV2). Asympthomatic in immunocompetent.
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Papovavirus - Polyomavirus
- DNA
- * Asymptomatic in immunocompetent.
- * Tumor induction, neurological disease and wasting in immunodeficient.
- * Intranuclear inclusions may be observed in lesions
- * C57BL mice are highly resistant; DBA/2 and BALB/c are resistantC57BR are susceptible as neonates but resist tumor induction
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Papovavirus - K-Virus (Murine pneumotropic virus (MPtV), or, Kilham polyomavirus (KPyV).
- DNA
- * Asymptomatic in immunocompetent adult mice
- * Persistent multisystemic infection in neonatal and athymic mice (intestine, lung, liver, spleen, adrenals). Target: vascular endothelium.
- * Intranuclear inclusion
- * May possibly be extinct
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Lymphocytic Choriomeningitis Virus (LCMV)
- * Arenaviridae; single stranded, enveloped RNA virus
- * Immunecompetent: self-limiting and asymptomatic
- * Model of virus-induced immune injury (T lymphocyte mediated)
- * Experimental infection: cerebral form (intracerebral inoculation); visceral form (peripheral inoculation with viscerotropic strains); neonatal infected with runting and death; and late-onset in carrier mice that develop immune complex glomerulonephritis
- * Zoonotic
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Lactate Dehydrogenase Elevating Virus (LDH)
- RNA Virus
- * Togavirus
- * No clinical signs in naturally infected mice
- * Increases concentration of enzyme, most notable lactate dehydrogenase (LDH)
- * Polioencephalitis in immunesuppressed C58 and AKR after experimental infection.
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Coronavirus: Mouse Hepatitis Virus (MHV)
- * Large, pleomorphic, enveloped RNA virus with radially arranged peplomers (spikes)
- * Enterotropic strains (intestinal tract) and polytropic strains (respiratory tract but can progress to multisystemic). Neurotropic strains can cause flaccid paralysis of hindlimbs
- * Clinical signs depend on age, strain and immune-status.
- * Yellow-white foci (necrosis) in multiple tissues, with lesions in liver as the classical finding. Syncytia is found in margin of necrotic areas and is hallmark of infection (found in intestine, lung, liver, spleen, lymph nodes, thymus, brain, bone marrow)
- * BALB/c are susceptible and SJL are remarkably resistant to polytropic strains.
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Paramyxoviral: Pneumonia Virus of Mice (PVM)
- * Paramyxoviridae; enveloped.RNA Virus
- * Asymptomatic in immunecompetent; respiratory disease and wasting in immunedeficient
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Sendai Virus (SeV)
- * Paramyxovirus; pleomorphic, single stranded, lipid-solvent-sensitive envelop RNA Virus
- * Respiratory disease, dyspnea, chattering sounds, crusting eyes. Lethal infection more common in suckling mice. Immune suppressed at high risk.
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Mouse Encephalomyelitis Virus (MEV) (TMEV) (Mouse Polio, or Theilovirus (ThV)
- * Picornaviridae; small, nonenveloped, cardiovirus RNA Virus
- * Neurological dz, flaccid posterior paralysis
- * Differentials: neurotropic variants of MHV, injury, neoplasia, polyomavirus infection on athymic mice (can induce tumors or demyelination)
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Reovirus
- * Double-stranded, segmented RNA
- * Reovirus 3 is the most common and associated with natural dz in mice
- * Clinical disease is rare and age dependant; acute disease in suckling with emaciation, abdominal distention, steatorrhea ("oily hair effect"), icterus. Reovirus 3: pantropic infection in infant mice; Reovirus 1: similar distribution but milder lesions; Reovirus 2: enterotropic.
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Rotavirus: Epizootic Diarrhea of Infant Mice (EDIM)
- * Double-stranded, segmented RNA
- * Age related susceptibility; clinical signs in infants less than 2 wks. Maternal antibodies protect. Signs: diarrhea, fecal soiling of perineum. Mortality is low.
- * Vacuolation of vilar epithelial cells with cytoplasmic swelling.
- * Differential: other diarrhea of suckling mice: MHV, reovirus 3, Tyzzer's dz, salmonellosis.
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Norovirus (Murine Norovirus (MNV)
- RNA Virus
- * Caliciviridae.
- * Non-pathogenic but lethal in GEMs with STAT1 deficiency (MNV-1)
- * MNV is the only known norovirus to replicate in vitro
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Clostridial diseases:
- C. perfringens
- C. difficile
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Corynebacterium: Gram positive, diphtheroid rods, in Chinese letter configurations
- C. kutscheri: Pseudotuberculosis
- Susceptible strains: BALB/c-nude, BALB/cCR, A/J, CBA/N, MPS
- C3H/He: Intermediate susceptibility
- Resistant strains: C57BL/6Cr, B10.BR/SgSn, ddY, ICR
- Grey-white nodules in kidney, liver, lung; cervical lymphadenopathy; mucopurulent arthritis, cartilage erosion, ulceration; septic, necrotic lesions with caseous material; subcutaneous abscesses
- C. bovis: Hyperkeratosis
- * Scaly skin , alopecia; generalized weakness
- * Keratoconjunctivitis in aged B6
- * B6, BALB/c, DBA/2, C3H/HeN, Swiss: Transient, low level infection
- * Haired SCID susceptible; Nude mice persistently infected
- * Increased toxicity of chemotherapeutic agents, decreased growth of transplanted tumors in nude mice
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Staphylococcus
- Streptococcus
- Mycobacterium
- M. chelonae : Tail infections/osteomyelitis in immunocompromised mice
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Mycoplasma:
- * M. coccoides : Transmitted by Polyplax serrata louse
- Diagnosis: Blood smears Romanowski stain or IFA
- * Mycoplasma pulmonis:
- Murine respiratory mycoplasmosis (MRM):
- Pleomorphic gram-negative bacterium that lacks a cell wall
- Sensitive: C57L, Balb/c, A/J, C58, C3H, DBA/2, SWR, AKR, CBA, SJL with varying degree.
- Resistant: C57BL, C57BR, B6, B10
- The major differential diagnosis is CAR bacillus disease. Other: Sendai Virus, pneumonia Virus of Mice, Corynebacteriosis, Pneumocystis infection in immunocompromised mice.
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Cillia - Associated Respiratory Bacillus Infection
- * CAR bacillus is a gram-negative organism.
- * Opportunist
- * Chronic respiratory disease in mice
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Tyzzer's Disease
- * Clostridium piliforme is a gram-negative, motile, filamentous, spore-forming bacillus and obligate intracellular parasite
- * Resistant: C57BL/6 (depleting NK cells or neutrophils increases susceptibility)
- * Sensitive: DBA/2, CBA/N and C3.CBA/N (B cell deficient)
- * Staining: Warthin-Starry, Giemsa, PAS
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Transmissible Murine Colonic Hyperplasia (TMCH): Citrobacter rodentium
- * Non-motile, gram-negative rod
- * Resistant: DBA, Balb/c, B6 and NIH Swiss
- * Susceptible: C3H/HeJ (both sucklings and adults), AKR and FVB
- * Colonization results in prominent mucosal hyperplasia.
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Helicobacter
- * Gram-negative microaerophilic, curved to spiral shaped.
- * Most prevalent: H. hepaticus and H. rodentium
- * Colonizes cecum and colon with variable presence in the liver
- * Usually asymptomatic in adults. Wasting, pneumonia (in immunocompromised mice), unformed, sticky, mucoid or hemorrhagic feces, rectal prolapsed.
- * Susceptible to hepatitis: A/JCr, SCID NCr, Balb/cANCr, C3H/HeNCr and SJL/NCr
- * Resistant to hepatitis: C57BL/6
- * Histopathology: silver stains (Steiner)
- * Differentials:
- o Enterocolitis and hepatitis � Coronavirus, Clostridium piliforme, Salmonella
- o Rectal prolapse � Citrobacter rodentium
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Salmonellosis
* S. enteritidis and S. typhimurium (mice)
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Streptobacillosis
- * Streptobacillus moniliformis
- * Pathogenic for humans: rat bite fever (Haverhill fever)
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Escherichia coli
- Klebsiella pneumonie:
- Leptospirosis
- Chlamydiosis
- * Chlamydia muridarum: Mouse pneumonitis (MoPn) agent
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Pneumocystosis: Pneumocystis murina
- * Opportunistic organism; clinically severe in immunodeficient mice
- * Pneumonia. Eosinophilic material in alveoli. Numerous rounded flattened cyst forms 3-5 um in diameter are present in active areas
- * Stains: Silver methenamine or PAS staining
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Dermatomycosis (Ringworm)
- * The most common fungal agent of mice
- * Signs: sparse haircoat, chalky surface on the head
- * Culture on Sabouraud's agar
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Myocoptes musculinus
- * Oval profile, heavily chitinized body. Dark brown 3rd and 4th pair of legs; "Boxing gloves" Tarsal suckers
- * Most common ectoparasite
- * Middle third of hair shaft; feeds off superficial epidermis
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Myobia musculi
- * Elongated profile. Single tarsal claw on 2nd pair of legs
- * Base of hair shaft; feeds on skin secretions
- * Immune sensitization of the host
- * C57BL are highly susceptible hypersensitivity dermatitis
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Radforia affinis
- * Elongated profile. Two claws at terminal tarsal structure of 2nd pair of legs (unequal in length)
- * Resembles Myobia, however it does not induce same signs as Myobia
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Psoregates simplex
- * Not common in lab mice
- * Inhabits hair follicles
- * Characteristic small white nodules in skin
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Demodex musculi
- * reported in transgenic mice lacking mature T cells and NK cells
- * Hair follicles
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Ornithonyssus bacoti
- * tropical rat mite
- * blood sucking, inhabits its host only to feed an then hides in nearby niches
- * intense pruritis
- * vector for Yersinia pestis, Q-fever, and murine typhus
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Lice
- Polyplax serrata
- * Common in wild mice, nonexistent in lab mice
- * Eggs attach to the base of hair shafts and hatch through an operculum at their top
- * P. serrata can transmit Mycoplasma coccoides and Francisella tularensis,
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Protozoal Disease
- Giardiasis: Giardia muris
- * Pear-shaped, flagellated organism with anterior sucking disk
- * "rolling, tumbling movement
- * C3H/He are susceptible and BALB/c and C57BL/10 are resistant
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Spironucleosis: Spironucleus muris
- * Elongated pear shaped bilaterally symmetrical
- * "horizontal and zig zag movements"
- * PAS stain
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Coccidiosis
- * Eimeria falciformis
- * Non-pathogenic coccidian in epithelial cells of the LI of mice
- * Klosiella muris
- * Renal coccidiosis in wild mice
- * Excreted in urine
- * Usually nonpathogenic and asymptomatic
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Cryptosporidiosis
- * Cryptosporidium muris--adheres to the gastric mucosa/slightly pathogenic
- * Cryptosporidium parvum--inhabits the SI and is non-pathogenic in immunecompetent mice
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Encephalitozoon cuniculi
* immunodeficient mice develop ascites and chronic wasting
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Entamoebias: Entamoeba muris
* Nonpathogenic
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Rodentolepis nana
- Hymenolepis diminuta
- Rodentolopis microstoma
- * Mice, rats, hamsters, and humans are susceptible to infection to Rodentolepis nana.
- * Utilize arthropods (beetles, fleas, moths) as an intermediate hosts. H. nana: beetle
- * R. nana can also have a direct life cycle in which onchospheres penetrate the mucosa and develop in the cysticercoid stage, subsequently emerging into the lumen as adults.
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Taenia taeniaformis (�Encysted Tapeworms)
* Mice can serve as intermediate hosts for the cat tapeworm Taenia taeniaformis
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Aspicularis tetraptera
- * adults live in the colon; mature females lay eggs in the descending colon which are then passed in the feces
- Egg: ellipsoidal, bilaterally symmetrical
- Eggs: infectious after 5-8 days at room temp
- Direct life cycle 23-25 days
- Eggs not deposited in the perianal area
- Adult worms found in the large intestine
- Dx by fecal examination
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Syphacia obvelata (mouse pinworm)
- * ubiquitous parasite of wild and laboratory mice
- * infestation usually asymptomatic (occasionally rectal prolapse)
- Egg: banana shaped
- Eggs: infectious after 6 hrs at room temp
- Life cycle direct 11-15 days
- Eggs deposited on skin and perianal region
- Adult worms found in cecum or colon
- Dx: by examining cellophane tape to perianal area or fecal
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* Alopecia Areata in C3H Mice
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* Seizures: DBA/2 , SJL and LP mice are prone to audiogenic seizures
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* Hypocallosity: Aplasia of the corpus collosum are common in BALB/c, 129's
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* Retinal Degeneration
- o Retinal degeneration due to homozygosity of the rd-1 (PDe6brd1 gene)
- o C3He, CBA, FVB, SJL, SWR
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* Atrial Thrombosis and Heart Failure
- o The left auricle is most frequently affected
- o RFM and BALB/c mice
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* Chronic Glomerulonephritis/glomerulonephropathy
o Naturally occurring autoimmune disease (NZB x NZW)
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* Microphthalmia and Anophthalmia: C57BL
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* Mucometra/Hydrometra: BALB/c, B6, and DBA
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