Respiratory 3 Flashcards
Pneumonia gross appearance
Even though it can be caused by the same pathogen, it can look different in different species. Can also cause lesions in other organ systems depending on the host species.
Many infectious causes of pneumonia have an ____ component in the pathogenesis.
Upper respiratory component
Bronchopneumonia tends to have ____ etiologies.
Bacterial etiologies
Interstitial pneumonia tends to have ____ etiologies.
Viral etiologies
Is color change reliable in evaluating pneumonia?
No! The severity of pneumonia cannot be assessed based on color change alone.
What is Mannheimia hemolytica?
What does it cause?
Among the most important pathogen of cattle in the US.
Cause of shipping fever.
Mannheimia hemolytica pathogenesis:
*Name the endotoxin it creates.
Shipment or other stressful event > often a coinfection with other pathogens (BoHV-1, PI-1, BRSV, pasturella multocidia, histophilus somni) and exposure to Mannheimia hemolytica.
This produces numerous virulence factors including an endotoxin called Leukotoxin.
Leukotoxin binds and kills bovine macrophages and neutrophils > leads to acute inflammation producing and responding to TNF-a, IL-1, IL-8, histamine and leukotrienes.
Describe the Mannheimia hemolytica lesion:
Severe bronchopneumonia, characterized by marked tissue necrosis, alveolar hyperemia and hemorrhage, alveoli filled with Suppurative inflammation, and wide interlobular septa expanded by edema and fibrin.
Histophilus somni clinical presentations:
Identical to what other pathogen?
Pneumonia and pleuritic: in cattle, infections can appear identical to Mannheimia hemolytica, pathogenesis is also similar.
Unlike Mannheimia hemolytica, it has numerous other presentations in other organ systems; myocarditis, arthritis, ophthalmitis, conjunctivitis, otitis, abortion, encephalitis and septicemia.
Pasturella multocidia in cows:
Often a co-infection with shipping fever (Mannheimia hemolytica)
Pasturella multocidia in pigs:
Can be a primary or secondary contributor to fibrinous bronchopneumonia (pleuropneumonia)
Associated with stressors such as poor ventilation.
Comparable to mannheimiosis in cattle.
Pasturella multocidia in rabbits:
*The primary respiratory pathogen of rabbits - pleuropneumonia.
Transmitted via aerosol from acutely infected rabbits, or by direct contact with fomites, colonization of nares and then spread to adjacent tissues.
Referred to as snuffles (URI)
Otitis occurs by extension through the Eustachian tube. Bacteremia may result in multifocal abscesses.
Pasturella multocidia in cats:
Pyothorax; secondary cause of bronchopneumonia.
B. trehalosi
What species does it effect, what does it cause?
Causes septic pasteurellosis of sheep.
Often cultured from mixed respiratory infections in cows.
Some strains produce Leukotoxin (similar to Mannheimia)
Closely related to pasturella species
Actinobacillus pleuropneumoniae
What species effected?
What disease does it cause?
Causes porcine pleuropneumonia (fibrinous bronchopneumonia).
Other presentations: young pigs (septicemia) weaned pigs (otitis interna)
Arcanobacterium pyogenes
What does it cause?
septic pulmonary emboli (embolic pneumonia)
common ruminant pathogen cultured from abscesses anywhere in the body.
Corynebacterium psudotuberculosis
What does it cause? In what species?
Causes ‘caseous lymphadenitis’ in sheep and goats.
Corynebacterium psudotuberculosis (pathogenesis)
Inoculation with bacteria via penetrating wounds or ingestion > macrophages phagocytose, carry to regional lymph nodes > bacteria multiply in LN, stimulates the development of pyogranumlomas. Macrophages disseminate bacteria at distant sites.
Corynebacterium psudotuberculosis (common locations for lesions)
Lymph nodes, lungs and subcutis.
Mycoplasma
Predominantly found on the mucosal surface of…
Why do you need a special media to grow?
Respiratory and urogenital tracts.
Tiny, fastidious bacteria that lack a cell wall and are difficult to grow on culture, special media required.
Mycoplasma bovis Causes... Where is the necrosis centered? What does it typically require? *What does it also present as?
Causes chronic, necrotizing bronchopneumonia with Suppurative or caseated abscesses in cattle.
Necrosis is centered around bronchi and bronchioles.
Infection typically requires immune suppression or stressor.
*Also presents as mastitis, arthritis, otitis, keratoconjucntivits, and abortion.
Mycoplasma mycoides ssp. mycoides. Cause of... Is this disease reportable? What does it cause? What is the Sequestra?
Cause of contagious bovine pleruopnemonia.
Yes it is a reportable foreign animal disease in the US.
Causes severe pleuropneumonia resembling (mannheimiosis) .
Sequestra of necrotic lung tissue due to vascular thrombosis, caudal distribution, and wider expansion of interlobular septa distinguish the lesions from Mannheimia.
Mycoplasma hyopneumoniae
Cause of…
What type of pneumonia does it cause?
What are outbreaks associated with?
Porcine enzootic pneumonia.
Suppurative and catarrhal bronchopneumonia.
Huge economic significance in the swine industry.
Outbreaks associated with poor environmental conditions: ventilation, high ammonia or hydrogen sulfide levels, high humidity, mixing and transport, overcrowding.
Clinical infections tend to be co-infections with other resp. pathogens.
Streptococcal pneumonia (streptococcus suis)
1) Transmission
2) Symptoms/sequela.
Oral and aerogenous depending on serotype, also can be transmitted vertically from infected sows.
Nursing or weanling pigs.
Bronchopneumonia, polyarthritis, polyserositis, abortions, neonatal septicemia, meningitis.
*Important zoonosis in humans (meningitis and septic shock)
Streptococcus in small animals
Hemolytic species of S.canis, S.equi, and S.zooepidemicus maybe associated with bronchopneumonia, septicemia, placentitis, and dermatitis in dogs and cats.
Mixed infections with pasturella multocidia, e, coli, klebsiella pneumonia, and Bordetella bronchiseptica are common.
Infections secondary to dental disease or iatrogenic infection related to dental cleaning..
Streptococcus zooepidemicus
What does it cause?
Gross lesion?
Cause of acute, hemorrhagic pleuropneumonia in dogs.
Diffuse pulmonary hemorrhage and necrosuppurative exudate with hemorrhagic pleural effusion.
Kennel environments - outbreaks with high morbidity and mortality- typically due to septicemic shock.
Rhodococcus equi; Presents in two systems... Source? Transmission? Spread?
Respiratory: Severe granulomatous bronchopneumonia in foals.
Intestinal: Ulcerative enterocolitis (often in foals)
Soil and feces.
Inhalation of infected dust and aerosols.
Bacteria are shed from infected foals.
Rhodococcus equi; pathogenesis for lung infection:
Foal inhales bacteria > alveolar macrophages phagocytose but are unable to kill the bacteria > bacteria multiply and rupture macrophages > lysosomal enzymes are released, neutrophils respond, inflammatory cytokines released > tissue damage with acute pyogranumlomas > bronchopneumonia causing death or bacteria continue to propagate in macrophages > chronic caseous pneumonia.
Mycobacterium bovis (pathogenesis)
*Cattle rarely infected by Mycobacterium TB.
Cause of bovine tuberculosis.
Inhalation of bacilli > phagocytosis by alveolar macrophages but inability to kill > bacteria multiply and rupture the macrophages > aerogenous ad within the lung > lymphatic invasion and lymphadenitis > widespread dissemination; vascular infiltration also possible.
Delayed type 4 hypersensitivity to the bacilli promotes slow development of caseous granulomas > chronic, granulomatous pneumonia and lymphadenitis.
Mycobacterium bovis
Zoonosis:
Wildlife hosts:
How to control?
Can be transmitted to humans through contaminated milk or aerosolization.
Deer in the US, badgers in the UK.
Control through intradermal skin testing and culling.
Bordetella bronchiseptica
Causes…
Transmission:
Can be associated with…
Inflammation of the trachea and bronchi in dogs, cats, pigs, and rodents.
Primary cause of kennel cough.
Aerosolization, direct and fomite contact.
Co-infections and bronchopneumonia in dogs.
