Key Terminology & Definitions - Bacteria & Fungi Flashcards
Mycobacteria
Nonmotile, non spore-forming, aerobic or microaerophilic pleomorphic coccobacilli, gram positive but are hard to stain due to abundant lipid
Mycobacterium avium
Most commonly causes mycobacteriosis in birds, but sometimes cattle, pigs, horses, sheep, primates
Mycobacterium tuberculosis
Mostly seen in humans but sometimes pigs, primates, dogs, cats, cattle, psittacine birds
Mycobacterium bovis
Persists in soil, can remain infective for weeks - high doses needed for oral transmission so environmental contamination is not an important means of transmission
Tuberculoid granuloma
Dynamic structure, prevents spread to other sites + hosts, cell-mediated response kills infected macrophages + forms caseous centre, bacteria in granulomas can remain dormant for long periods until something disturbs immune response
Tubercle
Classic gross lesion, circumscribed, often encapsulated, pale, yellow-white nodule, granulomatous inflammation and central caseous necrosis +/- mineral, large ones can liquefy and resemble abscesses, fibrosis inc w/ time + more forms in animals w/ greater resistance
Purified protein derivatives
Can produce delayed type IV hypersensitivity reactions in a sensitised animal (used in intradermal skin tests) to detect mycobacterium bovis
Mycoplasma sp.
Smallest self-replicating organisms, small genome, no cell wall , protein and lipid-rich plasma membrane, variation in surface antigens allows evasion of immune response, refractory to many antibiotics, obligate parasites with specific host and tissue tropisms, don’t survive in environment for lone, need close contact to spread
Enzootic
Low level of disease, constantly present in a population
Mycoplasma hyopneumoniae
Common, chronic, non-fatal disease of young pigs (grower-finishers), high morbidity + low mortality, usually non-productive coughing, poor growth + feed conversion, adheres to cilia, causes loss of cilia (+ 2^y effects), can predispose to fatal multifactorial pneumonia, plays role in porcine respiratory complex
PRRS
Porcine reproductive and respiratory syndrome (arterivirus)
Mycoplasma bovis
Carried and shed in secretions of respiratory, genital tracts and mammary glands, infection via direct contact with nasal secretions/milk in calves, high morbidity, low mortality, enzootic pneumonia of young calves, chronic pneumonia + polyarthritis in feedlot beef cattle, plays roles within bovine respiratory complex
Mycoplasma mycoides ssp. mycoides SC
Contagious bovine pleuropneumonia (CBPP), notifiable disease, small colony type, endemic to Africa (low incidence due to vaccine campaigns), variable clinical signs, morbidity + mortality, adults more susceptible than young, virulence also affected by strain, predisposing factors e.g. crowding, stress co-infection, virulence dec during outbreaks as is spreads through animals
Organising centres
Changes in interlobular septa, medial proliferation, look like vasculitis, blood vessel surrounded by proliferation of connective and inflammatory cells bounded by a peripheral zone of necrotic cells
Type I organising centres
More proliferative cells (inflammatory) in central zone
Type II organising centres
Proliferative cells are scarce and peripheral zone is relatively larger (immune system overwhelmed)
Mycoplasma ovipneumoniae
Atypical non-progessive chronic pneumonia, chronic, non-fatal disease in sheep and goats, affects all ages, usually young < 6 m/o, multifactorial disease triggered by stress, crowding, poor air quality, or host, reduced growth, chronic soft cough, nasal discharge, animals recover if management improved, lesions persist at least 7 months after recovery
Mycoplasma caprricolum spp. capripneumoniae
Contagious caprine pleuropneumonia, notifiable disease, goats, endemic to Africa, Middle East, India, high morbidity + mortality, lethargy, dyspnoea, fever, coughing, polyarthritis in young goats
Agalactia
An absence or failure of the secretion of milk
Mycoplasma agalactiae
Notifiable disease, can cause respiratory signs, contagious agalactia, adults = mastitis, agalactia, +/- arthritis, keratitis, youngstock = pneumonia, pleuropneumonia, chronic bronchopneumonia, fibrinosuppurative, polyarthritis, septicaemia
Mycoplasma equirhinis
Can rarely cause clinical signs in sports horses
Mycoplasma cynos
Most pathogenic part of multifactorial shelter respiratory disease
Feline mycoplasmas
M, felis, M. gatiae, M. arginini, may contribute to more complex disease
Aspergillus fumigatus
Ubiquitous environmental fungus, factors predisposing to disease following inhalation unclear
Exopthalmos
Inflammation behind eyes associated w/ infection in sinuses/nose -> pushes eye forward
Mycotic rhinitis
Mostly Aspergillus fumigatus, can distort nasal bones, extend into adjacent tissues causes
Pulmonary aspergillosis
Uncommon, usually haematogenous spread drom colitis (embolic), look for septate branching hyphae at lesion edges
Blastomyces dermatidis
Thermally dimorphic fungus - infectious, non-contagious disease of dogs and humans, primarily in North America, dimorphic fungus, grows as a mould in environment and yeast at body temp (once inhaled), likes acidic sandy soil especially if recently disturbed (fungi)
Cryptococcosis
Most common systemic mycosis of cats (+ dogs, horses, cattle, humans), sporadic, non-contagious disease, often causes chronic nasal disease, may cause ulcerative skin lesions, ocular disease, pneumonia, brain lesions, ascending mastitis in cows, filamentous form in environment, once spores inhaled they disseminate haematogenously
Cryptococcus neoformans
Temperate climates, found in soil + bird droppings, most common in dogs, usually requires immunosuppression for lesions
Cryptococcus gattii
Most common in cats, causes disease in immunocompetent animals
Coccidioidomycosis (Valley Fever)
Coccidiodes immitis or Coccidiosis posadasii - infect all mammals, dogs most common, endemic to SW US, central and South America, dimorphic fungus, mould like hot, dry conditions, infection by inhaling spores, infection more common than disease, respiratory distress, draining skin, nodules (cats)
Pneumocystis carinii
Sporadic disease of pigs, foals, dogs, usually requires immunosuppression, attaches to type I pneumocytes via cell wall glycoprotein A, cell-mediated immune response important to control, two forms (uninucleate trophic form, binary fission and thick-walled, multinucleate form, sexually) (fungi)
Entomopthoromycosis
Chronic nasal or cutaneous disease of horses, sheep, rarely cattle, all saprophytic (live in environment) fungi of tropical and subtropical climates, lesions most commonly in nostrils can form obstructive and invasive masses, sheep - ethmoid conchae most affected, ulcerating, cavitating granulomas with coral-shaped granules (fungi)
Dichotomous branching
Forking at 45 degree angles
Conidium
Type of asexual reproductive spore of fungi (kingdom Fungi) usually produced at the tip or side of hyphae
Sporangia
Capsule structure - where reproductive spores are produced and stored
Endosporulation
Rupture of sporangia, released endospore to start a new cycle
Oomycete
Fungal-like organisms phylogenetically related to algae
Pythium insidiosum
Produces similar lesions to Entomopthoromycosis, aquatic, fungus-like oomycete in horses, cattle, sheep, lots of eosinophils, thick-walled hyphae, infrequently septate (clinical finding = entomophthoromycosis, needs to be cultured/PCT or IHC to tell apart from entomophoromycosis - will have less hyphae, causes Swamp cancer syndrome
Rhinosporidium seeberi
Not really a fungus - an aquatic protist parasite, mostly humans and dogs, mostly wet tropical environments, infection via exposure to contaminated water, lesions = unilateral soft, pink nasal polys, bleed easily
Mortierella wolfi
In cows, acute fatal mycotic pneumonia secondary to placental infection, fibrinonecrotic pneumonia within a few days of parturition or abortion, due to haematogenous spread as the placenta detaches (embolic pattern in lungs), rare outside New Zealand (fungi)
Emmonsia sp.
Adiasporomycosis, mostly wild rodents but sometimes domestic animals, dimorphic fungus related to blastomycosis, granulomatous lesions in lungs, sometimes lymph nodes, diagnosed by finding large (300 μm), spherical, uninucleate adiaspores, thick PAS-positive wall (magenta satining), does not endosporulate
Histoplasma capsulatum
Fungi, causes pulmonary lesions, found in contaminated soil
Mucor and Rhizopus sp.
Fungi that can be opportunists in cows, caseous necrosis or granulomatous inflammation
