Cattle - Haemolymphatic Dz Flashcards

1
Q

In what breeds is Factor XI deficiency reported? What is the mode of inheritance and genetic defect which causes the condition?

A
  • Holstein, Holstein-Friesian and Japanese Black cattle.
  • Autosomal recessive inheritance.
  • Mutation of F11 gene.
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2
Q

What are the clinical manifestations reported in cattle with Factor XI deficiency?

A
  • Asymptomatic.
  • Prolonged bleeding.
  • Decreased resistance to infection.
  • Increased prevalence of repeat breeding.
  • Prolonged APTT, normal PT (intrinsic pathway only).
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3
Q

In what breeds is Factor VIII deficiency (Haemophilia A) reported? What is the mode of inheritance of this condition?

A
  • Japanese Brown and Hereford cattle; QHs.

- X-linked recessive; clinical disease usually occurs in males but is possible in females.

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4
Q

What are the clinical manifestations reported in cattle with Factor VIII deficiency (Haemophilia A)?

A
  • Factor VIII conc 5% normal: may see excessive haemorrhage post-trauma.
  • Prolonged APTT, normal PT (intrinsic pathway only).
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5
Q

Does vasculitis occur commonly in cattle? What agents has it been associated with?

A
  • Vasculitis occurs rarely in cattle.

- Has been reported secondary to septicaemic diseases incl MCF and Bluetongue.

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6
Q

List the aetiologic agent of Bovine Anaplasmosis.

A
  • Anaplasma marginale.
  • Obligate intraerythrocytic, gram-negative bacteria of the order Rickettsiales, family Anaplasmataceae, genus Anaplasma.
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7
Q

Describe the epidemiology of Bovine Anaplasmosis.

A
  • Transmitted by tickes of the ixodid spp, mainly Dermancentor in US and Rhipicephalus in tropical/subtropical climates.
  • Maintained by asymptomatic carrier state in cattle and possibly in wild ruminants.
  • Disease occurs in Summer and Spring.
  • Severity of CSx related to strain virulence, breed resistance, age-related susceptibility (younger).
  • Incubation period 15-30d.
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8
Q

List clinical signs of Anaplasmosis in cattle.

A
  • Fever, lethargy, anorexia.
  • Dec milk production.
  • Dec rumination.
  • Dry muzzle.
  • MM pallid or icteric if survive first 2-3d.
  • +/- neuro signs.
  • +/- constipation w dark brown, mucus-covered faeces.
  • +/- pollakiuria w dark yellow urine.
  • +/- abortion if infected during late gestation.
  • If survive: 3-4wk convalescence; infected for life (–> asymptomatic carrier).
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9
Q

Describe diagnostic test findings in cattle with Anaplasmosis.

A
  • Acute: rapid drop in PCV; 5-70% RBCs contain A. marginale morula on Wrights or Giesma stain.
  • Chronic: regen anaemia: anisocytosis, basophilic stippling, poikilocytosis, polychromatophilia, reticulocytosis.
  • Serology: cELISA highest sens/spec (OIE/USDA test for carriers) > complement fixation.
  • PCR on whole blood during acute infection.
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10
Q

Describe the pathophysiology of Bovine Anaplasmosis.

A
  • Most commonly ticks transfer to cattle; may be trans by biting flies, dehorning/castration etc equi, blood trans.
  • Bacteria rapidly replicates in vesicles in RBCs –> 10-90% infected.
  • Anaemia occurs secondary to splenic and hepatic macrophage phagocytosis of infected and non-infected RBCs.
  • Immune-reaction: auto-ABs against erythrocyte surface antigens and activation of macrophaghes to enhanve phagocytosis –> remove many but not all bacteria from blood (antigenic variants) –> recurring waves of bacteraemia and immune reactions.
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11
Q

Describe findings on necropsy of cattle that have died from Anaplasmosis. What finding differentiates this disease from Bovine Babesiosis, Leptospirosis, Copper toxicity and Clostridial infection?

A
  • No pathognomic findings.
  • Blood is thin, icterus, splenomegaly, hepatomegaly.
  • Lack of haemoglobinuria and haemoglobinaemia differentiates from other listed diseases as haemolysis is intravascular in Anaplasmosis.
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12
Q

Outline treatment and prevention methods for Bovine Anaplasmosis.

A
  • Tetracyclines NB do not prevent persistent infection.
  • +/- blood transfusion.
  • Endemic area: expose cattle when young –> asymptomatic carriers.
  • Non-endemic areas: live vacc of young cattle (only licensed in California in USA).
  • Tick spray, fly ear tags.
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13
Q

What other names is Babesiosis known by in cattle?

A
  • Piroplasmosis.
  • Tick fever.
  • Texas fever.
  • Redwater.
  • Tristeza.
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14
Q

List the aetiologic agents of Babeiosis in cattle.

A
  • > 6 species of Babesia can cause dz in cattle.
  • Intra-erthyrocytic protozoa.
  • USA:
    i) B. bigemina: big, pale, pear-shaped, acute angle paired inclusions.
    ii) B. bovis (more virulent): small, pleomorphic, round or pear-shaped, obtuse-angle paired inclusions.
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15
Q

Outline the epidemiology of Babesiosis in cattle.

A
  • Tick-bourne dz.
  • Transmitted by Boophilus spp in USA.
  • Trans by adults, nymphs, larvae of ticks or mechanical vectors e.g. biting flies, contained dehorning etc equip.
  • Incubation period: 5d->3wk.
  • Bos indicus and
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16
Q

List the clinical signs of Babesiosis in cattle.

A
  • Fever, depression, anorexia.
  • Icterus.
  • Tachypnoea.
  • Tachycardia.
  • Haemoglobinaemia and haemoglobinuria.
  • Abortion.
  • Death.
  • +/- central babesiosis (secondary to anoxia): hyperexciteability, opisthotonus, coma, death.
  • Outcome: death, asymptomatic carrier or persistent infection w recrudescence of infection and death.
17
Q

Describe the pathophysiology of Babesiosis in cattle.

A
  • Babesia enters bloodstream, infects RBCs.
  • Intravascular haemolysis due to emergency of merozoites from infected RBCs and osmotic fragility of whole (incl uninfected) RBC population.
  • +/- autoimmune removal of infected RBCs by spleen.
  • Results in rapid anaemia despite low parasitaemia.
18
Q

How is Babesiosis diagnosed in cattle?

A
  • Blood smear: organisms identified in RBCs following Giesma stain.
  • IFA or complement fixation.
19
Q

List necropsy findings in cattle with Babesiosis.

A
  • Pallor, icterus.
  • Enlarged liver.
  • Distended gall bladder.
  • Dark red urine (acute).
  • +/- hydropericardium.
  • +/- subepi, subendo, GI petechiae.
20
Q

Outline treatment of Babesiosis in cattle.

A
  • Supportive care: blood transfusion, IVFT, prophylactic ABs, minimal handling.
  • Anti-protozoals: imidocarb (tx and prev), diminazene diacturate, phenamidine diisethionate, amicarbalide diisethionate.
21
Q

Outline prevention of Babesiosis in cattle.

A
  • Young animals: live vaccine.
  • Older animals: live vaccine + imidocarb.
  • Sub-unit vaccines may modify severity of dz.
  • Tick control: acaricide, controlled range burning, cultivation, pasture rest.
22
Q

List causes of Heinz body haemolytic anaemia in cattle which are unique to those reported in horses.

A
  • Grazing selenium deficient pastures.

- Grazing rye grass (Secale cereale) pastures.

23
Q

Describe water intoxication as a cause of haemolytic anaemia in cattle.

A
  • Reported in milk-reared calves when first allowed water –> excess water consumption; 4-5mo at highest risk.
  • Prod marked hypotonicity of body fluids –> intravascular haemolysis due to osmotic lysis of RBCs.
  • CSx: neuro deficits, resp distress, haemoglobinuria and death in some cases.
  • Clin path: haemolytic anaemia, hypoproteinaemia, hypochloraemia, hyponatraemia, hyposmolality, haemoglobinuria, hyposthenuria.
  • Tx: restrict access to water; if profound hyponatraemia may need hypertonic saline, mannitol, corticosteroids.
24
Q

What is the aetiology of postparturient haemoglobinuria?

What is the signalment of cows most commonly affected?

A
  • Phosphorus deficiency –> low intracellular phosphate conc interferes w energy metab –> affects cell viability and ability of RBCs to cope w potential haemolysins.
  • High-producing multiparous cows that dev CSx within one month of calving.
25
Q

Describe the clinical presentation of postparturient haemoglobinuria in cattle.

A
  • Depression, dec feed consumption, dec milk prod.
  • Haemoglobinuria and icterus.
  • Marked anaemia w marked regen response after 4-5d.
26
Q

Describe treatment of postparturient haemoglobinuria in cattle.

A
  • Blood transfusion.
  • IVFT.
  • IV sodium acid phosphate followed by oral phosphorus supplementation.
  • Correct herd dietary imbalances.
27
Q

Describe the effect of bracken fern ingestion of the bone marrow of cattle and the subsequent clinical condition seen after 2-8wks on an affected pasture.

A
  • Bone marrow suppression –> pancytopaenia.
  • CSx: fever, melena, epistaxis, haematuria, mucosal petechiation, hyphema, bleeding from the eyes and vulva.
  • CBC: platelet count
28
Q

Describe the bacteria responsible for causing Anthrax.

A
  • Bacillus anthracis.
  • Vegetative form: large, rectangular-shaped, gram positive rod.
  • Vegetative form predominately found in infected animal tissues but can exist in enviro.
  • Forms spores under nutritionally limited conditions (aerobic process) –> stable in enviro for decades.
29
Q

Describe the epidemiology of Anthrax in livestock.

A
  • Found worldwide.
  • Soils with elevated pH, Mn++, Ca++ and rich in organic material favour spore survival.
  • Drought followed by heavy rain or earth-disturbing activities often –> outbreak.
  • Outbreaks usually during warmer part of year.
  • Bloodsucking insects transfer B. anthracis b/w animals.
  • Scavengers disseminated bacteria and carcasses of infected animals contaminate the enviro.
  • Susceptibility: ruminants > horses > pigs.
30
Q

Describe the pathophysiology of Anthrax in livestock.

A
  • Exposure: grazing contaminated pastures (spores), forage grown on contam pastures, animal by-products, insects.
  • Ingested anthrax spores gross mucosal barriers, phagocytosed by macro, travel to LNs –> convert to vegetative stage and kill host cell –> enter extracellular enviro.
  • Virulence factors:
    i) Poly-D-glutamic acid capsule: evade phagocytosis.
    ii) Three-component toxin: protective antigen - attaches to cell and on of other 2 factors, enters cell by endocytosis and forms pore to let other 2 factors in; lethal factor and oedema factor - interrupt cells immune functions, phagocytic capacity, cAMP prod –> oedema, cell death, expression of pro-inflamm cytokines.
  • B. anthracis proliferates rapidly in the host –> overwhelming septicaemia –> death due to hypotensive shock and multi-organ failure.
31
Q

List clinical signs of Anthrax in sheep, goats and cattle.

A
  • Typically peracute form –> sudden death.
  • May see fever, depression, resp distress, MM congestion, convulsions, bloody dxa, haematuria, localised tissue swelling.
32
Q

List clinical signs of anthrax in pigs.

A
  • Most common form: oropharyngeal form w swelling of head, neck, cervical LNs; may obstruct breathing and swallowing.
  • GI form present as dysentary.
  • Pregnant sows may abort.
33
Q

Describe findings on necropsy of animals that have died from Anthrax.

A
  • Carcass decomposes rapidly.
  • May see bloody exudates from body cavities and blood may not clot.
  • Spleen enlarged with ‘blackberry jam’ consistency.
  • LNs and internal organs may be oedematous and haemorrhagic.
  • Localised exposure may result in enteritis, regional LN involvement, peripheral tissue oedema.
  • Histo: large numbers of bacilli in affected tissues.
34
Q

Outline diagnostic test findings in Anthrax cases.

A
  • DO NOT OPEN CARCASS!!! –> sporulation of vegetative cells and contam of enviro; use PPE!!!
  • Dx based on microscopic exam of blood or tissue smears, bacterial culture; NB warn lab personnel (zoonotic risk).
  • Samples: blood, AQ, whole eye; LN if localised dz.
  • B. anthracis cells are destroyed during decomp, so take samples early.
  • Large, gram pos, square-ended rods found singly or in chains of 2-4; polychrome methylene blue (M’Faydean stain) identifies capsule surrounding the organism.
35
Q

Describe measures for treatment and control of Anthrax in large animals.

A
  • Report suspected case to local/state vet ASAP.
  • Tx often unrewarding/not possible due to peracute nature of dz; can try penicillin or oxytet for at least 5 days.
  • Carcasses should not be opened or moved; burn carcass and contam bedding/soil > deep burial.
  • Premise quarantined; clinically normal animals vaccinated w live acapsular vacc, vaccinate neighbouring herds, control insects and scavengers to limit spread.
  • Endemic areas: vacc 4 weeks prior to turning out on pasture where previous outbreak has occurred; rpt in 2-3 weeks if heavily contam area; goats and llamas may have severe adverse reactions to vaccine!
  • Ideally do not graze contam areas.
36
Q

Describe C. pseudotuberculosis infection in cattle.

A
  • Sporadic herd problem, doesn’t affect production.
  • Most common form is cutaneous excoriated granulomas’ mastitis, visceral and mixed infections also reported.
  • Granulomas: ulcerative, exuding, granulomatous lesions up to 20cm diam that can be excised to leave underlying granulation tissue bed; lesions usually on face, neck, thorax, flanks; spontaneous heal in 2-4wks.