Cattle - Haemolymphatic Dz Flashcards
In what breeds is Factor XI deficiency reported? What is the mode of inheritance and genetic defect which causes the condition?
- Holstein, Holstein-Friesian and Japanese Black cattle.
- Autosomal recessive inheritance.
- Mutation of F11 gene.
What are the clinical manifestations reported in cattle with Factor XI deficiency?
- Asymptomatic.
- Prolonged bleeding.
- Decreased resistance to infection.
- Increased prevalence of repeat breeding.
- Prolonged APTT, normal PT (intrinsic pathway only).
In what breeds is Factor VIII deficiency (Haemophilia A) reported? What is the mode of inheritance of this condition?
- Japanese Brown and Hereford cattle; QHs.
- X-linked recessive; clinical disease usually occurs in males but is possible in females.
What are the clinical manifestations reported in cattle with Factor VIII deficiency (Haemophilia A)?
- Factor VIII conc 5% normal: may see excessive haemorrhage post-trauma.
- Prolonged APTT, normal PT (intrinsic pathway only).
Does vasculitis occur commonly in cattle? What agents has it been associated with?
- Vasculitis occurs rarely in cattle.
- Has been reported secondary to septicaemic diseases incl MCF and Bluetongue.
List the aetiologic agent of Bovine Anaplasmosis.
- Anaplasma marginale.
- Obligate intraerythrocytic, gram-negative bacteria of the order Rickettsiales, family Anaplasmataceae, genus Anaplasma.
Describe the epidemiology of Bovine Anaplasmosis.
- 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.
List clinical signs of Anaplasmosis in cattle.
- 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).
Describe diagnostic test findings in cattle with Anaplasmosis.
- 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.
Describe the pathophysiology of Bovine Anaplasmosis.
- 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.
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?
- 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.
Outline treatment and prevention methods for Bovine Anaplasmosis.
- 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.
What other names is Babesiosis known by in cattle?
- Piroplasmosis.
- Tick fever.
- Texas fever.
- Redwater.
- Tristeza.
List the aetiologic agents of Babeiosis in cattle.
- > 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.
Outline the epidemiology of Babesiosis in cattle.
- 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