Babesia

Question 1

What are the key factors surrounding canine babesiosis?

Answer 1

• Babesia canis is the most common in europe
• It is transmitted by the Dermacentor reticulatus tick
• Most cases occur in the spring and autumn
• The geographical distribution is exapnding in europe

Question 1

What is babesia?

Answer 1

a blood-borne apicomplexan parasite that invades RBC’s in mammalian hosts

Question 2

What is the ‘uncomplicated’ pathogenesis of canine babesiosis?

Answer 2

• Invasion of RBCs → parasite multiplication → damage of membrane → haemolysis
• Anti-RBC membrane antibodies → cytotoxic destruction of RBCs

Question 3

What is the ‘complicated’ pathogenesis of canine babesiosis?

Answer 3

• Cytokine-mediated inflammation
• Tissue hypoxia affecting CNS, kidneys & muscles

Question 4

What are the clinical signs of canine babesiosis?

Answer 4

Acute babesiosis (inc. period 1-3 weeks) – fever, lethargy, jaundice, vomiting,
anorexia, anaemia
Chronic babesiosis – e.g. depression, intermittent fever, anaemia, myositis, arthritis

unless its subclinical then its asymptomatic

Question 5

How infectious is bovine babesiosis?

Answer 5

over half the worlds cattle is at risk of infection

Question 6

What is bovine babesiosis?

Answer 6

A sporadic tick-borne disease in the UK, causes infrequent outbreaks

Question 7

When do bovine babesiosis outbreaks usually occur?

Answer 7

The outbreaks generally occur in the spring, summer and autumn

Question 8

What does the epidemiology of bovine babesiosis depend on?

Answer 8

• Parasite species
• Age
• Stress
• Immunity

Question 9

What are the clinical signs of B.divergens (redwater fever)

Answer 9

• It is usually first reported in may/ june
• has an incubation period of 2 weeks
• Fever
• Diarrhoea
• Red urine
• increased pulse
• abortion
• death

Question 10

Simply explain the babesia lifecycle

Answer 10

• Parasite found on ticks
• Ticks bite a cow, it enters the bloodstream
• They reproduce, producing merozoites
• RBC’s burst
• when a new tick bites they enter the tick and undergo sexual reproduction in the ticks gut
• Formation of sporozoites which can then migrate up to teh ticks salivary glands
• re-enter another host when tick bites again

Question 11

How does transovarial transmission of babesia occur?

Answer 11

babesia parasites can be passed on to the larvae of the female tick if she is infected

Question 12

What are the two tick species that can transmit bovine babesiosis?

Answer 12

• Ixodes ricinus
• Rhipicephalus

Question 13

What is the best way to diagnose babesia (all species)

Answer 13

• History/ Clinical findings
• Haematological and biochemical tests
• Blood smears (Giemsa stain)
• PCR
• serology (antibody detection)

Question 14

What bebesia species can recover without treatment?

if caught early

Answer 14

B. divergens

Question 15

What are the two parasite species that can cause Bovine theileriosis?

Answer 15

• Theileria parva
• Theileria annulata

Question 16

What is the name of the tick that transmits Theileria parva?

Answer 16

Rhipicephalus appendiculatus

Question 17

What is the mortality of Theileria parva?

Answer 17

up to 95%

Question 18

What are the clinical signs of early east coast fever?

Answer 18

• High and sustained fever
• enlarged lymph nodes
• slight listlessness and decreased appetite

Question 19

What are the clinical signs of late east coast fever?

Answer 19

• increased respiratory rate
• depression
• anorexia
• death within 3-4 weeks of infection

Question 20

What is the pathogenesis of East Coast Fever?

Answer 20

• Proliferation of parasitised lymphocytes
• parasitised cells disseminate through the lympho-haemopoietic system
• they invade non-lymphoid tissues
• leukocyte depletion -> lymphoid tissues and blood leukocytes

Question 21

How can cattle become immune against east coast fever?

Answer 21

• any recovered cattle are solidly protected against the homologous challenge
• targets the schizont stage
• cell-mediated
• CD8+ T lymphocytes
• Strain-specific

Question 22

How can you diagnose east coast fever?

Answer 22

• Microscopic detection of parasites
• PCR
• detection of antibodies
  (antibody detection is either immunofluorescent antibodies or an ELISA with recombinant p85)

Question 23

What is the main vaccine you can use to treat east coast fever?

Answer 23

Inoculation with live sporozoites and simultaneous treatment with long acting oxytetracycline

Question 24

What are the two subunit vaccines that are used to treat east coast fever?

Answer 24

* CTL that targets antigens * p67- major surface protein

Question 25

What are the two ways we can implement vector control?

Answer 25

* Application of acaricides (dipping or spraying) * Tick vaccines

Question 26

What are four determinants of tick attack rate?

Answer 26

* Host density * Climate * Management practices * Latitude

Question 27

What vector transmits plasmodium?

Answer 27

It is transmitted via mosquitos

Question 28

What disease does plasmodium cause?

Answer 28

malaria

Question 29

What plasmodium species infects primates to cause 'monkey malaria' ?

Answer 29

Plasmodium knowlesi

Question 30

What are some of the drivers for the emergence of monkey malaria?

Answer 30

* Deforestation * Increased diagnosis * Inhibitory interactions between plasmodium species

Question 31

What is early east coast fever?

Answer 31

* High and sustained fever * enlarged lymph nodes * slight listlessness

Question 32

What is late east coast fever?

Answer 32

* Increased respiratory rate and respiratory distress * Depression * Anorexia Death within 3-4 weeks of infection

Question 33

What are some of the risk factors for 'monkey malaria'

Answer 33

* Human to human transmission * any vector associated with the forest

Question 34

What are some of the drivers for monkey malaria emergence?

Answer 34

* Deforestation- brings macaques and mosquitos to closer proximity * people venture into the forest for farming, hunting etc * change in vector behaviour