Equine Anemia: Piroplasmosis

Question 1

what is equine piroplasmosis

Answer 1

tick borne hemoprotozoan parasite

Question 2

how is equine piroplasmosis transmitted from the vector

Answer 2

tick salivary glands

Question 3

what infections can equine piroplasmosis cause

Answer 3

1. Theileria equi
2. Babesia caballi

Question 4

how is Theileria equi transmitted

Answer 4

intrastadial and transtadial transmission

Question 5

when do the clinical signs of Theileria equi

Answer 5

12-19 d after infection

Question 6

how is Babesia caballi transmitted

Answer 6

intrastadial

transtadial

transovarian

Question 7

when do the clinical signs of Babesia caballi appear

Answer 7

10-30 d after infection

Question 8

what is the life cycle of piroplasmosis

Answer 8

Question 9

what act as vectors in piroplasmosis

Answer 9

• Dermacentor*
• Rhipicephalus*
• Hyalomma*

Question 10

what is the pathogenesis of piroplasmosis

Answer 10

1. release of merozoits cause hemolysis
2. decreased survival of non infected red cells
3. microthrombi and vasculitis
4. thrombocytopenia
5. SIRS and progression to multiorgan system dysfunction
6. transplacental transmission in T. equi

Question 11

what can cause decreased survival of non infected red cells

Answer 11

1. hemoglobinemia may cause nephrosis
2. hypoxemia

Question 12

what is the risk to the UK

Answer 12

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

Question 13

what are the clinical signs for acute piroplasmosis

Answer 13

1. pyrexia, lethargy and hemolysis (PCV to 10%)
2. systemic signs depends on level of hemolysis: tachycardia, tachypnea, weakness
3. petechiations & marked thrombocytopenia
4. recurrent episodes of anemia

Question 14

what can occur to the kidneys in piroplasmosis

Answer 14

acute renal failure –> tubular nephrosis from hemoglobinuria, hypotension and systemic inflammation

pigmented urine (hemoglobin and bilirubin)

Question 15

what type if piroplasmosis is severe anemic syndrome more common with

Answer 15

T. equi

peracute hemolysis

death

Question 16

what are the less common clinical signs

Answer 16

1. colic
2. pneumonia
3. cardiac dysrhythmias
4. laminitis
5. infertility
6. CNS signs

Question 17

which piroplasmosis causes neonatal infection

Answer 17

T. equi

Question 18

what can the neonatal infection cause

Answer 18

abortion or neonatal piroplasmosis

severe hemolysis & icterus at birth or progressive signs from 2-3 days

Question 19

what are the clinical signs of neonatal infection

Answer 19

1. icterus, fever and anemia
2. loss of suck
3. progressive lethargy, weight loss
4. development of adult signs

Question 20

what are the differentials for non infectious causes of clinical signs

Answer 20

1. immune mediated hemolytic anemia
2. IM thrombocytopenia (idiopathic, drug related, neoplastic)
3. purpura hemorrhagica
4. maple leaf toxicity
5. neonatal isoerythrolysis

Question 21

what are the differentials for infectious causes of clinical signs

Answer 21

1. equine infectious anemia
2. equine viral arteritis
3. trypanosomosis (surra)
4. equine ehrlichoisis
5. african horse sickness virus

Question 22

what are the clinical signs of the chronic disease presention

Answer 22

commonest presentation

no clinical signs of disease

pregnancy may result in abortion or neonatal infeciton

acute hemolysis at times of concurrent disease

1. lethargy, poor performance
2. decreased appetite, weight loss
3. mild anemia may present

Question 23

how is piroplasmosis diagnosed

Answer 23

1. complement fixation test
2. indirect immunofluorscent antibody test
3. competitive ELISAs for T. equi & B. caballi
4. nested PCR

Question 24

what is the treatment

Answer 24

imidocarb dipropionate

carbamate –> causes reversible cholinesterase inhibition

Question 25

how do administer imidocarb dipropionate

Answer 25

admin may cause colic and diarrhea injection site necrosis --\> deep IM

Question 26

what is the treatment protocol for acute piroplasmosis

Answer 26

imidocarb 2.4 mg/kg preceded by glycopyrrolate 0.0025 mg/kg IV or hyoscine 0.14 mg/kg IV 1. blood transfusion may be required prior to imidocarb 2. fluid therapy to reverse acidosis and improve perfusion 3. increased drug toxicity with metabolic compromise

Question 27

is eradication possible

Answer 27

more likely with B. caballi persistence of EMA-1 and EMA-2 specific antibodies

Question 28

what are the import/export risks

Answer 28

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

Question 29

what is the current UK protocol

Answer 29

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

Question 30

in what ways could the UK control piroplasmosis

Answer 30

1. acaricidal treatment to all horses prior to UK import 2. vet inspection post import (follow up tick treatment) 3. consider ELISA or nested PCR as screening tests for horses remaining resident 4. isolation of seropositive horses 5. screening of cograzing horses with seropositive confirmed 6. continuation of tick capture with PCR tests

Question 31

should piroplasmosis be considered as a ddx for horses with hemolysis and pyrexia

Answer 31

yes cytological exam as first screening test