Equine Anemia: Piroplasmosis Flashcards
what is equine piroplasmosis
tick borne hemoprotozoan parasite
how is equine piroplasmosis transmitted from the vector
tick salivary glands
what infections can equine piroplasmosis cause
- Theileria equi
- Babesia caballi
how is Theileria equi transmitted
intrastadial and transtadial transmission
when do the clinical signs of Theileria equi
12-19 d after infection
how is Babesia caballi transmitted
intrastadial
transtadial
transovarian
when do the clinical signs of Babesia caballi appear
10-30 d after infection
what is the life cycle of piroplasmosis
what act as vectors in piroplasmosis
- Dermacentor*
- Rhipicephalus*
- Hyalomma*
what is the pathogenesis of piroplasmosis
- release of merozoits cause hemolysis
- decreased survival of non infected red cells
- microthrombi and vasculitis
- thrombocytopenia
- SIRS and progression to multiorgan system dysfunction
- transplacental transmission in T. equi
what can cause decreased survival of non infected red cells
- hemoglobinemia may cause nephrosis
- hypoxemia
what is the risk to the UK
free movement of horses between UK, France and ROI without border inspection
no specific guidelines on tick treatment
no requirement to test horses moving within EU
tick species capable of transmission present in UK
what are the clinical signs for acute piroplasmosis
- pyrexia, lethargy and hemolysis (PCV to 10%)
- systemic signs depends on level of hemolysis: tachycardia, tachypnea, weakness
- petechiations & marked thrombocytopenia
- recurrent episodes of anemia
what can occur to the kidneys in piroplasmosis
acute renal failure –> tubular nephrosis from hemoglobinuria, hypotension and systemic inflammation
pigmented urine (hemoglobin and bilirubin)
what type if piroplasmosis is severe anemic syndrome more common with
T. equi
peracute hemolysis
death
what are the less common clinical signs
- colic
- pneumonia
- cardiac dysrhythmias
- laminitis
- infertility
- CNS signs
which piroplasmosis causes neonatal infection
T. equi
what can the neonatal infection cause
abortion or neonatal piroplasmosis
severe hemolysis & icterus at birth or progressive signs from 2-3 days
what are the clinical signs of neonatal infection
- icterus, fever and anemia
- loss of suck
- progressive lethargy, weight loss
- development of adult signs
what are the differentials for non infectious causes of clinical signs
- immune mediated hemolytic anemia
- IM thrombocytopenia (idiopathic, drug related, neoplastic)
- purpura hemorrhagica
- maple leaf toxicity
- neonatal isoerythrolysis
what are the differentials for infectious causes of clinical signs
- equine infectious anemia
- equine viral arteritis
- trypanosomosis (surra)
- equine ehrlichoisis
- african horse sickness virus
what are the clinical signs of the chronic disease presention
commonest presentation
no clinical signs of disease
pregnancy may result in abortion or neonatal infeciton
acute hemolysis at times of concurrent disease
- lethargy, poor performance
- decreased appetite, weight loss
- mild anemia may present
how is piroplasmosis diagnosed
- complement fixation test
- indirect immunofluorscent antibody test
- competitive ELISAs for T. equi & B. caballi
- nested PCR
what is the treatment
imidocarb dipropionate
carbamate –> causes reversible cholinesterase inhibition
how do administer imidocarb dipropionate
admin may cause colic and diarrhea
injection site necrosis –> deep IM
what is the treatment protocol for acute piroplasmosis
imidocarb 2.4 mg/kg
preceded by glycopyrrolate 0.0025 mg/kg IV or hyoscine 0.14 mg/kg IV
- blood transfusion may be required prior to imidocarb
- fluid therapy to reverse acidosis and improve perfusion
- increased drug toxicity with metabolic compromise
is eradication possible
more likely with B. caballi
persistence of EMA-1 and EMA-2 specific antibodies
what are the import/export risks
OIE recommends ELISA and IFAT for pre import investigation of horses from endemic countries
positive horses moving for international competition (tick clearance and designated grazing)
risk to UK more likely due to tripartite agreement
legal and illegal trade
what is the current UK protocol
limited for piroplasmosis
pre-import testing within EU not required
only performed prior to re-exportation
ticks found on imported horses –> send for tick recording
in what ways could the UK control piroplasmosis
- acaricidal treatment to all horses prior to UK import
- vet inspection post import (follow up tick treatment)
- consider ELISA or nested PCR as screening tests for horses remaining resident
- isolation of seropositive horses
- screening of cograzing horses with seropositive confirmed
- continuation of tick capture with PCR tests
should piroplasmosis be considered as a ddx for horses with hemolysis and pyrexia
yes
cytological exam as first screening test
