4.1 Parasitology: Cardiovascular and Lymphoreticular Systems

Question 1

What is a piroplasm?

Answer 1

A group of blood-bourne tick-transmitted protozoa

Question 2

What type of parasite is babesia?

Answer 2

Protozoa

Question 3

Describe the Babesia life cycle

Answer 3

Tick feeds to transmit infection

Asexual multiplication in RBCs

Tick feeds and becomes infected

Sexual multiplication in tick intestine

Asexual multiplication in various tissues

Vermincules
- Tick salivary gland > Tick feeds to trabsmit infection
- tick ovary and eggs

Question 4

Explain babesiosis pathogenesis

Answer 4

Antigen replicates in RBC
RBC bursts to release babesia
Babesia infect other RBCs while remnants of antigen stick to healthy RBCs so the immune system attacks these instead of RBCs with babesia

Question 5

Symptoms of babesiosis infection

Answer 5

Sudden onset fever, anaemia, haemoglobunlinuria

Question 6

What type of parasite is Leishmania

Answer 6

An intra-cellular macrophage protozoa spread by mosquitos

Question 7

Describe the Leishmania life cycle

Answer 7

Leishmania ingested blood-sucking sandfly

Transforms and multiplies in fly gut (promastigote)

Migrates to proboscis

Inoculated during feeding and transforms in macrophage

Leishmania in vertebrate macrophage (amastigote)

Question 8

What is enzootic stability?

Answer 8

Many infected hosts
Frequent exposure
Boosted immunity
High level of herd immunity
Low level incidence of disease
High rate of transmission

Question 9

What is enzootic instability?

Answer 9

Few infected ticks
Infrequenct exposure
Reduced immunity
Low level of herd immunity
Higher incidence of diseases
Low rate of transmission

Question 10

What are the clinical signs of leishmania?

Answer 10

Ulceration of skin (cutaneous) especially on pinnae of the ears
Chronic wasting (visceral)
Generalised eczema
Intermittent fever
Most dogs asymptomatic and there is a long incubation period

Question 11

How would you diagnose leishmania?

Answer 11

Skin scrape/smear

Question 12

What type of parasite os Dirofilaria?

Answer 12

Nematode

Question 13

What are the chronic signs of Dirofilaria infestation?

Answer 13

Chronic heart failure
Sudden collapse
Long prepatent period so signs do not appear for months after infection

Question 14

Describe the lifecycle of Dirofilaria

Answer 14

Microfilariae (unsheathed) released into blood

Microfilariae ingested by mosquito and develop into L1-L3 (infective larvae)

L3 transmitted by feeding so deposited on skin and enter host through the puncture

Develops into L3, L4, L5

L5 migrates to the heart

Question 15

How can you prevent Dirofilaria infection?

Answer 15

Vector control - prevent mosquito bites

Question 16

What differences are there when Dirofilaria infects a cat rather than a dog its preferred host?

Answer 16

Reduced lifespan of the mature worm and the microfilariae

Highly pathogenic

Reduced worm burden

Effects lungs rather than heart

Cats less susceptible but higher mortality rate if they become infected