Arthropod-bourne infectious disease 1 Flashcards Preview

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Flashcards in Arthropod-bourne infectious disease 1 Deck (59):
1

What tick borne pathogens my be importe in dogs travelling from EU

NON ENDEMIC to UK: babesia canis canis, babesia gibsoni, ehrlichia canis
ENDEMIC TO UK: borrelia burgdorferi, anaplasma phagocytophilum

2

Which ticks are present in Europe?

- Ixodes ricin us: widespread
- Dermacentor reticularis: more restricted distribution
- Rhipicephalus sanguineus : life cycle requires temp > 18 degrees, not endemic in UK, intro from dogs travelling from EU, establish in houses / kennels here, vector for Mediterranean spotted fever (rickettsia conorii), carries babesia and ehrlichia

3

What are babesia and theileria?

Piroplasms

4

Most important agents of canine babesiosis

- LARGE BABESIA: b. Canis canis, B canis vogeli and B. Canis Rossi
- SMALL BABESIA: b. Gibsoni

5

How do different babesia spp vary?

- size
- vectors
- geo distribution
- Virulence
- prognosis
- response to tx

6

Babesia pathogens sis

- within ticks transmitted trans-stadially and trans-ovarially
- sporophytes injected from tick salivary glands
- enter circulation, endocytosed by RBC
- IM component of pathology
- TP common (but usually doesn't cause bleeding or abnormal coagulation)

7

Which babesia spp are zoonotic?

- b.microti - rodent reservoir
- b. Divergent - cattle reservoir

8

CS - babesiosis

- those of haemolytic anaemia
- lethargy, depression, inappetance
- icterus
- splenomegaly
- tachycardia and tachypnoea

9

Babesia - diagnosis

1 clinical laboratory findings: non-specific, TP common, many dogs are Coombs positive / auto agglutinate
2. Microscope identification : low sensitivity so must use another test to verify
3. PCR : high sensitivity, broad range babesia PCR, spp id possible using species specific PCR / sequencing
4. Serology: usually IFA or ELISA

10

Babesia - tx

- antibabesia drug : Imidiocarb dipropronate
- LARGE BABESIA: rapid clinical response
- SMALL FORMS : clinical and parasitological cure uncommon, clinical relapses may occur

11

What type of bacteria are rickettsia?

Small obligate intracellular gram negative

12

Which rickettsia infect monocytes?

- ehrlichia canis
- ehrlichia Chaffeensis: causes human monocytes ehrlichiosis, transmitted by ambylomma americanum, molecular evidence canine infections

13

Which rickettsial parasite infects thrombocytes?

Anaplasma platys

14

Which ricketssia infects granulocytes?

- anaplasma phagocytophilum
- ehrlichia erwingii

15

Incubation time - ehrlichia canis

1-3 weeks

16

Acute CS - ehrlichia canis

- vascular is and immune destruction leading to thrombocytopenia and cpagulopathy
- multi systemic signs
- spleen and LN enlargement
- CNS / ocular signs

17

Chronic - CS - ehrlichia canis

- BM destruction leading to pancytopaenia
- signs as for acute

18

Species infected by ehrlichia canis

Dogs and wild canids only

19

Diagnosis - ehrlichia canis

- modular in blood smears or macrophages from tissue as pirates (spleen, lung, LN)
- thrombocytopenia / pancytopaenia
- IFA/ELISA

20

Tx/ prevention - Ehrlichia canis

-tx: TCs for 28d/ chloramphenicol
- no vaccine
- chemo prophylaxis
- tick control

21

Anaplasma phagocytophilum - CS

- mild/ moderate TP
- lymphopaenia
- mild anaemia
- naturL chronic infection has not been seen
- impaired PMn function can predispose to secondary infection

22

A. Phagocytophilum in cats?

Very rarely

23

A.phagocytophilum - zoonotic?

Yes but unclear if infected domestic animals pose zoonotic risk. May have role as sentinels

24

What is Borrelia burgdorferi sensu lato associated with?

Lyme borreliosis

25

Hosts - borrelia

Humans, dogs incidental host (sylvatic tick- wildlife cycle)

26

What are the Borrelia pathogenic genospecies?

- b.afzelli (skin complications)
- b. Garinii (Neuro complications)
- b.burgdorferi sensu stricto ( the only pathogenic spp in USA, present in some parts of. Europe and can cause Neuro / arthritic complications)

27

What is the most prevalent tick- transmit infection in temperate areas of Europe, USA and Asia?

Lyme disease in people

28

CS - human Lyme disease

- erythema migrans in 80-90%
- later involves skin, Neuro and msk systems

29

Overall mean prevalence of b.burgdorferi in ticks in Europe

12%. Central Europe has highest tick infection rates

30

CS - borreliosis in dogs

- co infections common
- lethargy, anorexia and pyrexia
- inflammatory PA
- inflammatory arthritis
- lymphadenopathy
- protein losing glomerulonephropathy

31

Dx - borreliosis in dogs

- no pathognomic test
- a symptomatic seroconversion common
- microscopic / genetic detection often not possible

32

Tx - borreliosis in dogs

Empirical AB tx (doxycycline - amoxicillin)

33

Describe leishmania

- flagellate Protozoa
- phlebotomous vector
- reservoir host
- non- vector routes of transmission: venereal, blood products, direct contact (skin wounds)

34

What is the most important leishmania spp in Europe?

L. Infantum

35

Outline canine Leishmaniosis in Europe

- 2.5 million infected in France, Spain, Italy and Portugal
- infection rates 70-90% in some areas (Spanish Balearics)
- prevalence requires PCR and serology
- in North Europe infection generally restricted to dogs travelling from endemic area ( and high sandfly exposure March to November)

36

UK dog Leishmaniosis situation

Infected dogs are potential reservoir should incursion of a competent vector occur

37

Outline leishmania lifecycle

Promos tigons develop in macrophages - ingested by sandfly rep, infected human/ dog - flagellate amastigote in sandfly - then becomes inoculated into dog/ human

38

Pathogenesis - leishmania

- macrophage is target cell
- systemic infection in haemolymphatic organs
- parasite persistence can cause chronic infection
- protective immunity mediated by TC
- signs may develop months to years after infection > 7 years

39

What determines leishmania clinical outcome?

- host immune response
- also:
- age (2-4 and >7 more susceptible)
- breed
- nutrition
- concurrent dz
- immunosuppression

40

CS - leishmania

Chronic systemic dz
- usually visceral and cutaneous signs
- waxing and waning

41

Dx - canine leishmania

1. Demonstration of parasite: definitive diagnosis, specificity 100%, sensitivity

42

Tx - canine leishmaniasis

- ANTILEISHMANIAL DRUGS: often give clinical remissions persistent parasite ai, meglumine antimoniate ('glucantime') + allopurinol, prolonged tx, not licensed for use in UK
- consider euthanasia d/t zoonotic risk, especially where endemic

43

Prevention - canine Leishmaniosis

- sandfly avoidance
- topical insecticides: imidacloprid/ permethrin spot on 2d before travel, deltamethrin collars 2 wks before travel
- vaccine available

44

Human Leishmaniosis - CS

- cutaneous
- visceral ( can be fatal)
- mucocutaneous
- self- limiting / sub clinical

45

At risk groups for human Leishmaniosis

Young, immunosuppression, poor

46

Primary route of infection - human leishmania

Sandflies from dogs, also possibly direct contact

47

T/f: human and canine Leishamnia correlated at population level

True

48

Dirofilaria immitis - distribution

- endemic in Europe USA, Australia np but not UK

49

Vector - dirofilaria immitis

Mosquito (>70spp can transmit)

50

What does dirofilaria immitis cause?

- heart worm
- occupy RHs heart and PA
- CS: coughing, dyspnoea, decrease exercise tolerance and right sided heart failure
- cats more resistant than dogs but dz can occur
- zoonotic

51

PPP - dirofilaria immitis

6 months

52

Prophylaxis - dirofilaria immitis

- selamectin (stronghold)
- milbemycin (milbemax)
- moxidectin (advocate)

53

Dirofilaria immitis - tx

1. Symtomatic - steroids and tx CHF
2. Adults code - melarsomine
3. Microfilarial - levamisole, ivermectin, milbemycin

54

What type of bacteria is bartonella?

Small gram negative haemotropic bacteria. Different host- adapted spp within bartonella

55

What is commonest bartonella in cats?

Bartonella hensellae (also B. Clarridgeiae)

56

Prevalence of bartonella

Widespread - seroprevalence up to 40%. Feline dz reported but unusual.

57

Main relevance of bartonella

Zoonotic potential - causes cat scratch disease. Causes lymphadenomegaly in immunocompetant hosts. Roughly 125 human cases / year in UK. Serological diagnosis but indirect IFA.

58

Why may diagnosis of arthropod borne diseases be complicated?

Long incubation period and aasymptomatic states.

59

What is the pets travel scheme?

- protect pets and UK disease status
- rabies and tapeworm tx
- no tick tx

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