Arthropod-bourne infectious disease 1 Flashcards

1
Q

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

A

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

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2
Q

Which ticks are present in Europe?

A
  • 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
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3
Q

What are babesia and theileria?

A

Piroplasms

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4
Q

Most important agents of canine babesiosis

A
  • LARGE BABESIA: b. Canis canis, B canis vogeli and B. Canis Rossi
  • SMALL BABESIA: b. Gibsoni
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5
Q

How do different babesia spp vary?

A
  • size
  • vectors
  • geo distribution
  • Virulence
  • prognosis
  • response to tx
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6
Q

Babesia pathogens sis

A
  • 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)
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7
Q

Which babesia spp are zoonotic?

A
  • b.microti - rodent reservoir

- b. Divergent - cattle reservoir

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8
Q

CS - babesiosis

A
  • those of haemolytic anaemia
  • lethargy, depression, inappetance
  • icterus
  • splenomegaly
  • tachycardia and tachypnoea
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9
Q

Babesia - diagnosis

A

1 clinical laboratory findings: non-specific, TP common, many dogs are Coombs positive / auto agglutinate

  1. Microscope identification : low sensitivity so must use another test to verify
  2. PCR : high sensitivity, broad range babesia PCR, spp id possible using species specific PCR / sequencing
  3. Serology: usually IFA or ELISA
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10
Q

Babesia - tx

A
  • antibabesia drug : Imidiocarb dipropronate
  • LARGE BABESIA: rapid clinical response
  • SMALL FORMS : clinical and parasitological cure uncommon, clinical relapses may occur
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11
Q

What type of bacteria are rickettsia?

A

Small obligate intracellular gram negative

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12
Q

Which rickettsia infect monocytes?

A
  • ehrlichia canis
  • ehrlichia Chaffeensis: causes human monocytes ehrlichiosis, transmitted by ambylomma americanum, molecular evidence canine infections
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13
Q

Which rickettsial parasite infects thrombocytes?

A

Anaplasma platys

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14
Q

Which ricketssia infects granulocytes?

A
  • anaplasma phagocytophilum

- ehrlichia erwingii

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15
Q

Incubation time - ehrlichia canis

A

1-3 weeks

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16
Q

Acute CS - ehrlichia canis

A
  • vascular is and immune destruction leading to thrombocytopenia and cpagulopathy
  • multi systemic signs
  • spleen and LN enlargement
  • CNS / ocular signs
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17
Q

Chronic - CS - ehrlichia canis

A
  • BM destruction leading to pancytopaenia

- signs as for acute

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18
Q

Species infected by ehrlichia canis

A

Dogs and wild canids only

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19
Q

Diagnosis - ehrlichia canis

A
  • modular in blood smears or macrophages from tissue as pirates (spleen, lung, LN)
  • thrombocytopenia / pancytopaenia
  • IFA/ELISA
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20
Q

Tx/ prevention - Ehrlichia canis

A
  • tx: TCs for 28d/ chloramphenicol
  • no vaccine
  • chemo prophylaxis
  • tick control
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21
Q

Anaplasma phagocytophilum - CS

A
  • mild/ moderate TP
  • lymphopaenia
  • mild anaemia
  • naturL chronic infection has not been seen
  • impaired PMn function can predispose to secondary infection
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22
Q

A. Phagocytophilum in cats?

A

Very rarely

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23
Q

A.phagocytophilum - zoonotic?

A

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

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24
Q

What is Borrelia burgdorferi sensu lato associated with?

A

Lyme borreliosis

25
Q

Hosts - borrelia

A

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

26
Q

What are the Borrelia pathogenic genospecies?

A
  • 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
Q

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

A

Lyme disease in people

28
Q

CS - human Lyme disease

A
  • erythema migrans in 80-90%

- later involves skin, Neuro and msk systems

29
Q

Overall mean prevalence of b.burgdorferi in ticks in Europe

A

12%. Central Europe has highest tick infection rates

30
Q

CS - borreliosis in dogs

A
  • co infections common
  • lethargy, anorexia and pyrexia
  • inflammatory PA
  • inflammatory arthritis
  • lymphadenopathy
  • protein losing glomerulonephropathy
31
Q

Dx - borreliosis in dogs

A
  • no pathognomic test
  • a symptomatic seroconversion common
  • microscopic / genetic detection often not possible
32
Q

Tx - borreliosis in dogs

A

Empirical AB tx (doxycycline - amoxicillin)

33
Q

Describe leishmania

A
  • flagellate Protozoa
  • phlebotomous vector
  • reservoir host
  • non- vector routes of transmission: venereal, blood products, direct contact (skin wounds)
34
Q

What is the most important leishmania spp in Europe?

A

L. Infantum

35
Q

Outline canine Leishmaniosis in Europe

A
  • 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
Q

UK dog Leishmaniosis situation

A

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

37
Q

Outline leishmania lifecycle

A

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

38
Q

Pathogenesis - leishmania

A
  • 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
Q

What determines leishmania clinical outcome?

A
  • host immune response
  • also:
  • age (2-4 and >7 more susceptible)
  • breed
  • nutrition
  • concurrent dz
  • immunosuppression
40
Q

CS - leishmania

A

Chronic systemic dz

  • usually visceral and cutaneous signs
  • waxing and waning
41
Q

Dx - canine leishmania

A
  1. Demonstration of parasite: definitive diagnosis, specificity 100%, sensitivity
42
Q

Tx - canine leishmaniasis

A
  • 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
Q

Prevention - canine Leishmaniosis

A
  • sandfly avoidance
  • topical insecticides: imidacloprid/ permethrin spot on 2d before travel, deltamethrin collars 2 wks before travel
  • vaccine available
44
Q

Human Leishmaniosis - CS

A
  • cutaneous
  • visceral ( can be fatal)
  • mucocutaneous
  • self- limiting / sub clinical
45
Q

At risk groups for human Leishmaniosis

A

Young, immunosuppression, poor

46
Q

Primary route of infection - human leishmania

A

Sandflies from dogs, also possibly direct contact

47
Q

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

A

True

48
Q

Dirofilaria immitis - distribution

A
  • endemic in Europe USA, Australia np but not UK
49
Q

Vector - dirofilaria immitis

A

Mosquito (>70spp can transmit)

50
Q

What does dirofilaria immitis cause?

A
  • 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
Q

PPP - dirofilaria immitis

A

6 months

52
Q

Prophylaxis - dirofilaria immitis

A
  • selamectin (stronghold)
  • milbemycin (milbemax)
  • moxidectin (advocate)
53
Q

Dirofilaria immitis - tx

A
  1. Symtomatic - steroids and tx CHF
  2. Adults code - melarsomine
  3. Microfilarial - levamisole, ivermectin, milbemycin
54
Q

What type of bacteria is bartonella?

A

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

55
Q

What is commonest bartonella in cats?

A

Bartonella hensellae (also B. Clarridgeiae)

56
Q

Prevalence of bartonella

A

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

57
Q

Main relevance of bartonella

A

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

58
Q

Why may diagnosis of arthropod borne diseases be complicated?

A

Long incubation period and aasymptomatic states.

59
Q

What is the pets travel scheme?

A
  • protect pets and UK disease status
  • rabies and tapeworm tx
  • no tick tx