114. Diseases of farm animals caused by corynebacteria. Flashcards
Aetiology of Corynebacteria?
Aetiology
- Morphology: Gram-positive rods (club shape common), lipids & mycolic acids in the cell wall
- (resistance is fairly good)
- Occurrence: skin, MM, soil, water, surface of plants
- C. diphtheriae: toxin, diphtheria (human pathogen, rarely colonise animals)
- Certain strains infected with bacteriophage which encodes a diphtheria toxin causing diphtheria
- C. pseudotuberculosis
- C. renale, C. cystitidis, C. pilosum
- C. kutscheri: rodents, pneumonia, septicaemia
- C. bovis: mastitis, abortion (rare)
- C. ulcerans: diphtheria toxin, phospholipase D, cat, dog, pig, human
Diseases caused by Corynebacteria?
Diseases caused by Corynebacteria
- Caseous lymphadenitis of sheep and goats
- Ulcerative lymphangitis of horses
- Oedematous skin disease (OSD)
- Pyelonephritis, urethritis and cystitis caused by corynebacteria
Caseous Lymphadenitis of sheep and Goats Occurence?
Caseous lymphadenitis of sheep and goats
Occurrence:
- world-wide,
- sporadic,
- in warmer climate more frequent
Etiology of caseous lymphadenitis?
Etiology:
- C. pseudotuberculosis (2 biotypes/variants → caused by nitrate negative variant/ovine variant)
- Nitrate negative; Phospholipase D (attack RBCs - cause haemolysis ; attack endothelial cells); Lipid
- Facultative intra cellular
- Resistance fair
Epidemiology of caseous lymphadenitis?
Epidemiology
- Introduction by asymptomatic carrier animals
- Infection: per os, inhalation, wounds (sharp food, shearing, dipping, castration)
- Appearance of clinical signs is slow
- Clinical signs in growers above 3-4 months and adults
- Asymptomatic infection
- Classical chronic disease – never seen in suckling lambs
Pathogenesis of Caseous Lymphadenitis?
Pathogenesis
- Replication in phagocytes: resulting in lysis of phagocytes
- (release interleukins & mediators →
- attract inflammatory cells, further lysis, pus)
- Wounds: local lesions, lymph nodes abscessation (nodal form)
- Generalisation (visceral form)
- Blood → spreading (lungs, liver, udder, joints)
- Abscesses, abortion, arthritis
- Antibodies 3-6 weeks after the infection
Clinical signs of Caseous lymphadenitis?
Clinical signs
- Fever, anorexia, anaemia
- Enlarged LNs - Superficial abscesses: rupture, discharge (can compress trachea/oesophagus)
- Lambs: arthritis, tenosynovitis
- Abortion
- Generally no generalisation in goats (only localised form);
- In cattle rare
Lesions and diagnosis of caseous lymphadenitis?
Lesions:
- abscesses (lungs, mediastinal LNs, laminated onion-like layers in sheep),
- sometimes purulent arthritis
Diagnosis
- Epidemiology – clinical signs – laboratory examination
- Detection of the agent: culture, microscopy, PCR
- Antibodies – produced against the phospholipase:
- ELISA (toxin) → don’t use because just shows that the flock is infected
Differential diagnosis, treatment and prevention of caseous lymphaenitis?
Differential diagnosis:
- Morel’s disease (lesions similar, cocci in smear),
- purulent bacteria
• Treatment:
- penicillin, tetracycline, erythromycin, rifampicin, transitory results (problems: intracellular
- bacterium & in the middle of abscesses so treatment often not successful)
• Prevention
- Movement restrictions
- Culling, isolation
- Vaccination: inactivated, toxoid; attenuated (deleted toxin gene) – not widely done, results unsure
- Eradication: test and slaughter (ELISA)
Oedematous skin disease of Buffalo’s?
Oedematous skin disease of Buffalos
- Occurrence: Egypt, Nile delta
- Aetiology: C. pseudotuberculosis (nitrate positive, sometimes diphthery toxin is produced)
- Epidemiology: transmitted by flies and horse flies, or via wounds
- Clinical signs: skin oedema (thigh, chest, belly)
- Diagnosis, treatment: see caseous lymphadenitis
- Prevention: arthropod control
Ulcerative Lymphangitis of horses (pigeon breast, Dryland distemper) Occurence and ethiology?
Ulcerative lymphangitis of horses (Pigeon breast, Dryland distemper)
Occurrence:
- sporadic,
- more frequent in warmer climate,
- rare in Europe
Etiology:
- C. pseudotuberculosis (nitrate-positive variant);
- phospholipase D (attacks RBCs – haemolysis & endothelial cells)
Epidemiology and Clinical signs Ulcerative Lymphangitis of horses?
Epidemiology:
- infection; wound, navel, arthropods, aerosols
Clinical signs:
- infection, lymphangitis (inflam. of lymphatic vessels & form small nodules that rupture),
- abscesses (ruptured, blood tinged pus) → ulcers; mainly on only one leg, painful but not itching, fever, inappetance
- Classical continuous/chronic process → eventually the animals cannot heal
- Lesions located in the breast area & legs
- Animals don’t die – no pathological lesions
Diagnosis and treatment and prevention Ulcerative Lymphangitis of horses?
Diagnosis
- Epidemiology - clinical signs
- Bacteriology: isolation, microscopy (direct smear – other bacteria can be present)
Treatment:
- surgical opening of the nodules (labourous), disinfection, antibiotics (penicillin, rifampicin,
- tetracycline)
Prevention:
- hygiene,
- clean environment,
- prevention of wounds, arthropod control
Bovine pyelonephritis Ethiology and Epidemiology?
Bovine pyelonephritis
Etiology:
- C. renale,
- C. pilosum,
- C. cystitidis
Epidemiology:
- sporadic,
- chronic,
- typically in adults after 2nd/3rd calving,
- cattle (horse, pigs),
Pathogenesis and clinical signs Bovine Pyelonephritis?
Pathogenesis:
- slow appearance of CS, ascending infection
- (urine of infected animals is the source of infection);
- pyelonephritis (purulent inflammation),
- urethritis,
- cystitis (haemorrhagic inflammation)
Clinical signs:
- frequent, painful urination
- (arched back, painful sound of animal),
- haematuria, inappetance,
- decreased milk production
- (due to decreased eating & drinking)
