Vector-borne diseases of small animals

List the main vector borne diseases

• Ehrlichiosis

• Anaplasmosis

• Lyme borreliosis

• Babesiosis

• Bartonellosis

What are the bacterial tick borne diseases

• Ehrlichiosis

• Anaplasmosis

• Rickettsiosis

• Lyme borreliosis

What are the protozoal tick borne diseases?

• Babesiosis

• Hepatozoonosis

What are the viral tick borne diseases?

Tick-borne encephalitis

What aetiological agent causes Ehrlichiosis?

E. canis —> infects monocytes

What transmits Ehrlichiosis?

Rhipicephalus sanguineus

What are the phases of ehrlichiosis?

Acute (2-4 weeks)

• Lymphadenopathy & splenomeglay

• Thrombocytopaenia (anaemia, petechiae, epistaxis, melaena)

• Ocular signs (uveitis, retinal detachment)

Subclinical (months to years)

• Recovery from acute phase

• Mild asymptomatic thrombocytopaenia

Chronic

• Signs of bone marrow dx

• Bleeding tendencies —> petecchiae, ecchymosis, epistaxis

• 2° infection

• History & diagnostic testing to differentiate

What clinicopathological changes are present with ehrlichiosis?

• Acute/subclinical —> thrombocytopaenia

• Chronic —> pancytopaenia

• Lymphocytosis

• Hypoalbuminaemia, hyperglobulinaemia

• Monoclonal gammopathy

• Proteinuria

How do you diagnose Ehrichiosis?

• Cytology —> Morula within monocytes (low sensitivity)

  

• Serology IFA/ELISA —> abs between 7-28 days (acute phase might be missed)

• PCR —> low sensitivity

What is an Idexx 4DX test?

Serology

What are the limitations of testing for serology?

• +ve test can be because of past dx

  • Many can recover spontaneously and be positive for months/years

• Seroprevalence high in dogs from endemic areas

• 12-14 days for antibodies to be produced so active infection can be -ve

How does a PCR compare to doing serology?

-ve serology rules out Ehrlichia (except for active infections less than 14 days old), whereas a +ve PCR confirms Ehrlichia infection

How do you treat Ehrlichiosis?

• Doxycycline

  • 10mg/kg PO q24hrs for 28 days

How do you prevent ehrilichiosis?

Tick control

What aetiological agents cause anaplasmosis and what transmits them?

A. phagocytophilum spread by Ixodes ricinus

A. platyus spread by Rhipicephalus sanguineus (ONLY US)

What does A. phagocytophilum cause?

Canine granulocytic anaplasmosis

What signs are associated w/ anaplasmosis?

• Usually subclinical, self limiting

• Fever, lethargy, inappetance, lameness, lymphadenomegaly, splenomeglay, neutrophilic (immune-mediated) polyathritis → joint effusions + pain

• Thrombocytopenia

• NB- Zoonotic

What is the main difference between anaplasma and ehrlichia?

Anaplasma does not have a chronic form

What clinical pathological changes are associated with anaplasmosis?

• Thrombocytopenia (neutropenia, lymphopenia more rarely)

• Lack of lymphocytosis (unlike Ehlrichia)

• Non specific changes in biochem —> hyperglobinaemia, hypoalnbuminae

What tests can be used to diagnose anaplasmosis?

• Cytology —> morula within neutrophils

• Serology —>IFA/ELISA good for >7-10 days

  • Paired titres

  • Cross reactivity between Anaplasma and Ehrlichia can lead to false +ves

• PCR —> good sensitivity

How is anaplasmosis treated?

Doxyxycline

prevention with tick control

What aetiological agent causes lyme borreliosis & what transmits it?

• B. burgdorferi

• Ixodes ricinus transmits

What is the significance of a +ve titre for lyme disease?

• A high titre does not predict illness

  • May not get clinical signs

What are the forms of lyme disease?

• Lyme arthritis

• Lyme nephritis

  • Proteinuria → protein-losing nephropathy

  • Thromboembolism, pulmonary thromboembolism, hyperextensive damage, nephrotic syndrome, PUPD

How is lyme borreliosis diagnoesd?

• Cytology —> presence of morulas in joint effusion

  

• Serological

  • 4dx snapp test —> does not react w/ vaccine

  • Lyme C6 Quant —> quantified can be used to monitor respsonse to tx

If a dog is seropositive for lyme borreliosis what should you do?

1. Screen for proteinuria (UPCR)

2. Check for vector borne co-infections

3. Tick control!

How is lyme borreliosis treated?

Doxycycline

control with tick control

What are the two species of babesia causing large babesiosis & their vectors?

• B. canis —> dermacentor reticularis

• B. vogeli —> rhipicephalus sanguineus

What are the two species of babesia causing small babesiosis and their vectors?

B. vulpes —> Ixodes hexagonous

B. gibsoni —> Rhipicephalus sanguineus

What are the clinical signs of babesia?

• Intravascular haemolysis —> pallor, icterus, regenerative anaemia, haemoglobinuria, haemoglobinaemia

• Thrombocytopenia —> petechiae, epistaxis

• Lymphadenomegaly

How do you diagnose babesiosis?

• Cytology —> poor sensitivity but good first step

• Antibodies (IFA) —> high titre indicates exposure but not active infection

• PCR to identify species

What is used to treat babesia?

Imidocarb (large babesia)

• Some dogs remain chronically infected and at risk of relapse particularly with immunosuppression oand splenectomy

How is babesiosis prevented?

• Vaccine (pirodog) —> reduced clinical signs

• Tick control

What aetiologicla agent causes bartonellosis and what transmits it?

• B. henselae

• Ctenocephalides felis

What does bartenellosis cause in dogs?

• Endocarditis

• Signs —> fever (also afebrile), lethargy, lymphoadenomegaly

• Complications —> thromboembolic disease, neutrophilic polyarthritis, heart failure

  • Signs —> lameness, epistaxis, cough

What clinicopathological chnges are associated with bartonellosis?

Not specific —> non-regen anaemia, thrombocytopenia, neutrophilia

How is bartenellosis diagnosed?

• Culture (blood / tissue) —> low sensitivity

• Enrichment PCR —> low sensitivity (as culture) but diagnostic test of choice

• Serology (IFA/ELISA) —> positive does not means active disease. Also bacteraemia can be present without antibodies.

How do you treat bartonella?

Doxycycline and fluoroquinolone

(prognosis for bartonella endocarditis = guarded)

How is bartenollosis prevented?

Flea control