Disorders of the Hematopoietic System Food Animal 2024 PDF

Disorders of the Hematopoietic System VHM 322 Dr. Emily John Outline  Red blood cells  Coagulation disorders  White blood cells  Anthrax  Caseous lymphadenitis  Camelids Regenerative Anemia  Ruminants do display regenerative response in...

Disorders of the Hematopoietic System VHM 322 Dr. Emily John Outline  Red blood cells  Coagulation disorders  White blood cells  Anthrax  Caseous lymphadenitis  Camelids Regenerative Anemia  Ruminants do display regenerative response in peripheral blood  Increased MCV, decreased MCHC  Marked anisocytosis  Polychromasia  Basophilic stippling  Howell-Jolly bodies, nucleated RBCs Case Study  3 week Holstein heifer  5 day history diarrhea, sometimes hemorrhagic; 8% dehydrated  Referred in for plasma transfusion  rDVM bloodwork, day 1 AM:  PCV 24%  Total protein 50 g/L Case Study - Bloodwork Day 1 PM Day 2 AM Day 2 PM Day 3 AM PCV 19 % 18% 16% 10% TP 42 g/L 39 g/L 47 g/L 47 g/L Dehydration 7% 5% 6% 8% Hemorrhage Internal External Clotting abnormalities Abdominal Endoparasitism Hereditary deficiencies - Neoplasia - Haemonchus - Platelet function - Splenic rupture Ectoparasitism - Clotting factor Thoracic Abomasal ulcer deficiencies - Pulmonary trauma - Diet Chronic bracken fern - neoplasia - Neoplasia toxicity Severe coccidiosis Caudal vena cava syndrome Hemorrhage Hemorrhage  Hypoxic dementia  Keep in mind for patients with hemorrhage as well as blood donors  Fecal occult blood testing  Blood transfusion  Impractical to find “universal” donor  Disease-free donor  Herd/flock-mate Oxidative Hemolysis  Plant or chemical toxicities  Allium spp.  Brassicas  Selenium deficiency  Copper toxicity Copper Toxicity  Sheep most sensitive  Calves; adult cattle, goats  Molybdenum and sulfur protective  Inhibit copper absorption Copper Toxicity  Sources:  Feeds formulated for other species  Pastures treated with chicken/swine manure  Orchard crops – copper-containing fungicides  Copper fencing, piping Copper Toxicity - Pathogenesis  Hepatic accumulation  Massive liver necrosis  See increased hepatocellular leakage enzymes  Copper in bloodstream causes oxidative hemolysis  Intravascular hemolysis  Pigment nephropathy, Hb-uria  Death due to anemic crisis, organ failure Copper Toxicity – Clinical Signs Copper Toxicity – Diagnosis  Post-mortem findings  History of exposure  Blood/tissue copper levels Copper Toxicity – Treatment and Prevention  Supportive care  Medications to encourage copper excretion  Blood transfusion  Guarded prognosis  Prevention:  Appropriate feed  Molybdenum supplementation Bovine Anaplasmosis  A. marginale  Tickborne disease (Dermacentor)  Present in USA; immediately notifiable in Canada Anaplasmosis – Clinical Signs  Infected as calf:  Mild malaise 1-2 d then lifelong inapparent infection  Infected as adult:  High fever with anorexia, lethargy, depression  Marked anemia (extravascular hemolysis) with icterus – no Hb-uria!  High mortality rate; prolonged convalescence Anaplasmosis – Diagnosis  History, geographic location, clinical signs  Anemia with intra-RBC morulae  cELISA (OIE-approved test) Anaplasmosis – Treatment and Control  Supportive care and tetracyclines  Will not 100% clear infection  Control strategies:  Tick control  Endemic areas, high transmission – expose cattle when calves  Endemic areas, low transmission – blood-based vaccine  Non-endemic areas – screening and quarantine of imports Babesiosis  Reportable disease in Canada  Intravascular hemolysis = will have hemoglobinuria (unlike Anaplasma) Other causes of Hemolytic Anemia  Infectious:  Hemobartonellosis, Eperythrozoonosis  Leptospirosis  Bacillary hemoglobinuria  Miscellaneous:  Water intoxication  Postparturient  Congenital erythropoietic porphyria Depression Anemia  Information in notes  Also for polycythemia Platelet Disorders  Hereditary Chediak-Higashi syndrome  Thrombocytopenia  Bone marrow insult  Decreased survival  DIC  Immune-mediated  Thrombocytosis  Common with systemic inflammation Dicoumarol Toxicity  Conversion of coumarin in forage to dicoumarol via mold growth  Clinical signs consistent with impaired coagulation  Vitamin K1 for treatment  Remove feed; “cycle” with other feed if impossible Caudal Vena Cava Syndrome  CVC thrombosis secondary to hepatic abscess (secondary to rumenitis)  Sudden death or respiratory signs (acute or chronic)  Diagnosis via necropsy  Ultrasonographic changes Caudal Vena Cava Syndrome Bluetongue  Orbivirus of sheep  Cattle are amplifier hosts; rare clinical disease  Clinical signs due to systemic vasculitis  Considered ovine equivalent of human viral hemorrhagic fevers (Ebola, Marburg) Bluetongue – Clinical Signs Bluetongue – Prevention Bovine Leukocyte Adhesion Deficiency (BLAD)  First report: 1983  Almost absent from Holstein breed now  2018: BLAD confirmed in Lineback cattle in US Bovine Lymphoma  Two main forms  Sporadic  Generally young animals  B or T cell involvement  Enzootic  Usually older animals  B cell involvement Sporadic Bovine Lymphoma  Juvenile  3-6 months old  Acute onset, rapid progression  Anemia, lymphocytosis Sporadic Bovine Lymphoma  Thymic  6 months – 2 years  Signs due to space-occupying mass  Bloodwork unremarkable Sporadic Bovine Lymphoma  Cutaneous  Wider age range  Painful nodules +/- ulceration  Anemia, atypical lymphocytes Enzootic Bovine Leukosis  Adult form of bovine lymphoma  Bovine leukemia virus: deltaretrovirus  Persistent infection  Dairy > beef EBL – Clinical Signs  Infection ≠ clinical disease  30% of infected cattle develop persistent lymphocytosis  Up to 5% develop lymphoid tumors  Nonspecific clinical signs:  Anorexia  Lethargy  Decreased milk production  Enlarged superficial LNs EBL – Clinical Signs EBL – Epidemiology  Retrovirus spread by blood contamination  Shared needles/syringes  Rectal sleeves?  Live bull breeding  Biting flies?  Virus (and antibodies) in colostrum  In utero infection EBL – Epidemiology  Immune system genotype influences  Susceptibility to infection  Tendency to develop clinical disease  Development of high proviral load  Prevalence high in North America EBL – Economics  BLV-positive cows:  Earlier culling  Increased susceptibility to disease  Decreased response to vaccination  Other costs:  Reduced milk production (herd level)  Carcass condemnation  Export restrictions EBL – Diagnosis  Physical examination of clinically affected cows  Histopathology on LNs  Serology  ELISA for anti-BLV antibodies  PCR for viral antigens  Serology for individual and herd status EBL – Control and Prevention  Minimize blood transfer between animals  Colostrum management  Fly control  Segregate BLV-positive and negative cows  Test bulls used for live breeding  Closed herd/buy only BLV-negative animals  Targeted culling of high-PVL animals Anthrax  Bacillus anthracis  Regional disease based on soil characteristics  “Anthrax corridor” of North America  Important differential for sudden death in ruminants and horses  3-part toxin involved in pathogenesis Anthrax – Clinical Signs  Ingested or inhaled forms  Found dead  Fever, depression, respiratory distress  Cutaneous  Dark-coloured external lesions Anthrax – Diagnosis  Lack of rigor mortis  Unclotted blood at orifices  Characteristic bacterial appearance on smear Anthrax – Treatment and Prevention  Systemic antimicrobials for affected animals  Live spore vaccine for at-risk populations  Move animals to different pasture  Prevent soil contamination  Proper carcass disposal  Discourage scavenging Caseous Lymphadenitis  C. pseudotuberculosis  Major cause of abscesses in small ruminants  Widespread prevalence CL – Clinical Signs  External abscesses  Enlarged superficial LNs  May spontaneously rupture; white/green pus  Internal abscesses  Chronic weight loss most common sign  Respiratory compromise, colic CL – Clinical Signs CL – Epidemiology  Infection via bacteria/pus entering skin abrasion/wound  Fly bites  Fighting  Shearing/vaccination/castration  Exposure very common  “Tip of the iceberg” disease CL – Diagnosis  Assume any external abscess in a small ruminant is CL until proven otherwise!  Culture of abscess fluid  Diagnostic imaging to identify internal abscesses  Valuable breeding stock/pets  Characteristic abscess appearance  SHI serology – US laboratories CL – Treatment  Drain abscesses, flush with iodine  Properly dispose of any contaminated materials  Surgical LN removal  Antimicrobial therapy CL – Prevention and Control  Isolate or cull affected animals  Vaccination with regular examination of flock/herd and culling animals with external abscesses  Shearing/vaccination  Young animals first, affected animals last  Single-use needles Camelid Hematology Camelids – Anemia  Red maple toxicity  Mycoplasma haemolamae  Endoparasitism  C3 ulceration Juvenile Llama Immunodeficiency Syndrome  Suspected hereditary immunodeficiency  Young llamas (+/- alpacas)  Stunted growth  Chronic or recurrent infections  Low circulating B-cell levels