Leishmania and babesia

Question 1

In which cells are Babesia spp. found in?

Answer 1

Erythrocytes

Question 2

Draw and label a babesia parasite in a host red blood cell.

Answer 2

Paired merozoites seen here (B. divergens)

Containing nucleus and apical complex

Question 3

Outline the Babesia lifecycle.

Answer 3

1. Tick has blood meal and ingests infected RBC
2. ++Multiplication and sexual repro in the tick, protozoa is disseminated in tick tissue and moves to ovaries.
3. Once tick feeds protozoa in the salivary glands sporulate.
4. Sporozoites are injected into the hosts.
5. Sporozoites invade RBCs and develop into merozoites ( multiply by binary fission.

Question 4

Which tick species are associated with babesiosis transmission in EU?

Which species of babesia is involved?

Answer 4

Dermatocentor reticulatus

Rhipicephalus sanguineus

B. canis

Question 5

Name two species of Babesia which are considered large and small, what are their general sizes?

Answer 5

Small - divergens, bovis - 1-2um

Large - bigemina, major, canis - 4-5um

Question 6

Describe risk factors which can predispose dogs to canine babesiosis infection.

Answer 6

• Tick infestation or exposure (transmission time from tick to the host is unknown).
• Travelled in the EU
• Recent dog bite (B gibsoni).
• Blood transfusion from infected donor.
• Splenectomy.
• Immunosuppression.
• Transplacental transmission

Question 7

How does Babesia cause babesiosis disease in the dog?

Answer 7

By invading RBCs the protozoa causes haeomlytic anaemia via:

• immune-mediated (intra and extra vascular)
• direct parasitic injury
• oxidative stress

Question 8

Describe clinical signs whichmay be associated with canine babesiosis.

Answer 8

• Lethargy.
• Pale mucous membranes.
• Splenomegaly.
• Waxing and waning pyrexia.
• Bounding pulses.
• Lymphadenopathy.
• Generalized weakness.
• Jaundice.
• Vomiting (more commonly reported with B conradae infection).

Question 9

Outline diagnostic procedures which are used in canine babesiosis.

How are infecitons treated?

Answer 9

• Light microscopy
  
  • enhanced capillary blood
  • intracellular parasites are identified
• iFAT - doesn’t distinguish between species
• PCR

Imidocarb Tx.

Question 10

Which intermediate host is responsible for transmitting leishmaniasis to dogs?

How can transmission risk be decreased?

Answer 10

Phlebotomus sandflies

Use deltamethrin impregnated collars

House dogs at dusk and dawn (when flies are at their greatest)

Question 11

Why can leishmaniasis infection generally not occur in the UK?

Answer 11

Climate:

• Too cold for sandflies to overwinter
• Too cold for parasitic development

Question 12

Outline the pathogenesis of Leishmaniasis infection in dogs.

Answer 12

Immune response:

• Cell mediated immune response (TH1) - infection controlled
• Humoral immune response (TH2) - antibodies are ineffective against infection
  
  • Multisystemic granulomatous inflammation and immune-complex mediated lesions (glomerulus, vasculitis)

Question 13

Describe clinical signs associated with Leishmaniasis.

Answer 13

General: Lethargy, Change in appetite, Wt loss (+/- cachexia and muscle atrophy), Generalized lymphadenomegaly, Splenomegaly, PUPD, V/D

Cutaneous: Nonpruritic exfoliative dermatitis ± alopecia, Erosive-ulcerative dermatitis mostly at mucocutaneous junctions (ears, nose,eyes), Nodular or papular dermatitis, Pustular dermatitis, Onychogryphosis

Ocular: Keratoconjunctivitis (common or sicca), Blepharitis, Anterior uveitis/endophthalmitis

Other: Lameness, Epistaxis, Mucosal lesions (oral, genital), Myositis and polymyositis, atrophic masticatory myositis, Cutaneous and systemic vasculitis

Question 14

Outline the lifecycle of Leishmania.

Answer 14

Question 15

Dx. Leismania

Answer 15

• Clinical signs and history
• iFAT
• ELISA - serology correlates with severity of disease
• Amastigotes in cytology/ histo of affected tissues