GI ruminant ID

Actinomycosis

• aetiology

• epidemiology

• clinical findings

• clinical pathology

• treatment

• aetiology - Actinomyces bovis (commensal of oral cavity)

• epidemiology - cattle fed course feed, damages buccal mucosa and gums

• clinical findings

  • hard, immovable lump on maxilla or mandible = pyelogranulomatous osteomyelitis

  • —> lumpy jaw

  • may ooze small amounts of thick pus with yellow-white granules

• clinical pathology - gram +ve filamentous rods found by staining granules found in pus (club colonies)

• treatment

  • debridement

  • oral or IV iodine

  • parental penicillin or oxytetracycline

Actinobacillosis

• aetiology

• epidemiology

• clinical findings

• clinical pathology

• treatment

• aetiology - Actinobacillus lignieresii (commensal of upper GI tract)

• epidemiology - grazing abrasive pasture plants, causes damage to GI tract

• clinical findings

  • difficulty with prehension and mastication

  • swelling and abscessation of tongue and draining LNs (+ lips in sheep)

  • —> wooden tongue

• clinical pathology - purulent discharge containing sulfur bodies = granular, club-like rossettes with central foci of gram negative bacteria

• treatment

  • oral or IV iodides

  • streptomycin, penicillin or sulfonamides

Oral and laryngeal necrobacillosis

• aetiology

• epidemiology

• clinical findings

• clinical pathology

• treatment

• aetiology - Fusobacterium necrophorum (commensal of GI tract)

• epidemiology - oral disease associated with oesophageal feeder injury

• clinical findings

  • unpleasant smelling breath, inspiratory dyspnoea and stridor (high pitched breathing sound)

  • necrotic lesions of oral mucosa —> necrotic stomatitis

  • necrotic lesions of larynx —> calf diphtheria

• clinical pathology - bacteriology of swabs (anaerobic culture) —> gram -ve, non-spore forming, rod-shaped

• treatment

  • antimicrobial for 5+ days

  • debridement may be needed

  • tracheostomy if severe necrotic laryngitis

Enterohaemorrhagic Escherichia coli

• aetiology

• epidemiology

• clinical findings

• aetiology - subtype of E.coli that is shiga-toxin producing

• epidemiology

  • no clinical disease in ruminants

  • disease in humans through contaminated food/water, direct contact with EHEC carrying animal, undercooked meat or raw milk

• clinical findings

  • in humans only

  • mild-bloody diarrhoea

  • haemorrhagic colitis

  • haemolytic uremic syndrome

Salmonellosis

• aetiology

• epidemiology

• clinical findings

• clinical pathology

• treatment

• aetiology

  • = gram -ve, rod shaped bacilli

  • cattle - S. Typhimurim, S. Dublin, S. Mbandaka, S. Newport, S. Enteritidis, S. Montevideo

  • sheep - S. Typhimurim, S. Dublin, S. enterica subsp. diarizonae, S. abortusovis

• epidemiology - common routes = contaminated feed and environment, transport, introduction of carrier animal

• clinical findings

  • septicaemia

  • abortion

  • enteritis

  • localised tissue infection - arthritis, osteitis, terminal dry gangrene (ear tips, tail, below fetlock)

  • calves - necrotising enteritis, malabsorption, diarrhoea

• clinical pathology - culture (but complicated due to intermittent shedding) and ELISA serology

• treatment

  • acute - use antimicrobials based on susceptibility (but antimicrobial controversial due to resistance)

  • oral and IV fluids

  • NSAIDs

  • vaccines

Clostridium perfringens

• aetiology

• epidemiology

• clinical findings

• clinical pathology

• treatment

• aetiology - types A, B and C based on production of toxins

• epidemiology - dietary change or engorgement are risk factors, young fast growing well-nourished animals (with mother not vaccinated)

• clinical findings (type A)

  • haemorrhagic enterotoxaemia

  • haemolytic disease - see depression, collapse, pallor, jaundice, haemoglobinuria, dyspnoea

  • abomasal ulcers

  • swollen dark brown kidneys

  • pale and swollen liver

• clinical findings (types B and C)

  • haemorrhagic diarrhoea

  • abdominal pain

  • toxaemia

• clinical pathology - smears of faeces or intestinal contents but it is commensal so subjective diagnosis, can test for presence of toxin (not routinely done in labs)

• treatment

  • anti-toxins available

  • oral and parenteral penicillin to prevent further proliferation of pathogen

  • intensive fluid therapy

  • prognosis often poor for haemorrhagic bowel syndrome

Winter dysentery

• aetiology

• epidemiology

• clinical findings

• treatment

• control

• aetiology - coronavirus

• epidemiology

  • faeco-oral transmission, high morbitidy, low mortality

  • housed cattle in winter months

• clinical findings

  • sudden onset diarrhoea in majority of herd

  • fever, milk drop, inappetance

  • recovery within a few days

  • enterocolitis

• treatment - none

• control - hygiene and reduced overcrowding

Papular stomatitis

• aetiology

• epidemiology

• clinical findings

• treatment

• control

• aetiology - bovine papular stomatitis virus (parapox virus)

• epidemiology - common in young animals, zoonotic

• clinical findings

  • papules and vesicles on face, muzzle, mouth, udder, oesophagus and fore-stomach

  • ulceration and secondary infection

  • inappetence and weight loss

• treatment - supportive treatment may be needed (resolves spontaneously)

• control - hygiene, reduce overcrowding

bovine viral diarrhoea (BVD)

• aetiology

• epidemiology

• clinical findings

• treatment

• control

• aetiology - bovine viral diarrhoea virus (BVDV) —> pestivirus with noncytopathic and cytopathic biotypes

• epidemiology

  • persistently infected animals are major source of infection

  • virus found in all secretions

  • spread via direct transmission, flies, fomites, airborne, AI

• clinical findings

  • subclinical —> mild disease with inappetance, depression, fever, leukopenia, mild diarrhoea

  • peracute —> respiratory depression, anorexia, watery diarrhoea, conjunctivitis, fever

  • mucosal disease in PI animals

• treatment - none

• control - detection and eradication of PI animals, strict biosecurity

Mucosal disease

• aetiology

• epidemiology

• clinical findings

• treatment/control

• aetiology - BVDV

• epidemiology - persistently infected animal becomes infected with cytopathic BVD

• clinical findings

  • ulceration of mucosa throughout GI and respiratory tract

  • vasculitis

  • fever, tachycardia, tachypnoea

  • poor ruminal contractility, foul-smelling diarrhoea, blood and fibrinous casts in faeces

  • mucopurulent nasal discharge

  • death

• treatment/control - none, animals need to be culled