SA Arthropod Borne Infectious Dz Flashcards
What affects the risk of introduction of vector borne dz?
- VECTOR and PATHOGEN
- within infected animal (possibly subclinical)/fomites
What are arthropods?LOOK SLIDES ONLINE
lice/fleas etc.
What is the PETS?
- pet travel scheme
- protect individual pets and UK Dz status
- requires RABIES and TAPEWORM (echinococcus multilocularis, Praziquantel) tx (used to need tick tx but dont now)
See lecture for tickborne pathogens imported in dogs travelling from EU
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Which tickbrne pathogens are non-endemic to the UK and which are ednemic?
> non-endemic - babesia canis canis - babesia gibsoni - erhlichia canis > endemic - borrelia burgdorferi - anaplasma phagocytophilum
What is the caster bean tick? Distribution?
- Ixodes ricinis
- WIdespread
What is the brown dog tick?
> Ripicephalus sanguineus
- life cycle requires > 18*
- NOT ENDEMIC UK but can establish in kennels etc
- vector for meditteranean spotted fever (Rickettsia Conorii) humans, Babesia and Ehrlichia
What is babesiosis?
-protozoan parasite of RBCs transmitted by ticks
- 2 main genera Babesia and Theileria = piroplasms
> pathogen s
- large (b canis canis: EUrope, b canis vogeli: Africa, USA: Europe, Australia, b canis rossi: S Africa)
- small (B Gibsoni: Asia, Africa, USA, S. EUrope)
Where are babesia infections common?
- eurpoe
Pathogenesis of babesia?
- WITHIN TICKS trans-stadially and trans-ovarially (from larva to adult and adult to larva)
- sporozoites injected from tick salivary glands
- enter circulation, endocytosed by RBCs
- immune mediaed component of pathology
- thrombocytopenia common (but usually not cause of abnormal bleeding etc, anaemia most noted pathology)
Is Babesia zoonotic?
No but infected ticks may cross to humans if they possess a differnt strain
Which babesia affect humans? Reservoir?
> B. Microti - rodent reservoir > B. Divergens - cattle reservoir *most important causes of human Babesiosis*
Clinical signs of babesiosis?
- hemolytic anaemia
- lethargy, depression, inapetence
- icterus
- splenomegaly
- tachycardia/tachypnoea
How can babesia be dx on lab findings? ?
- Lab findings
- non specific
- thrombocytonpenia common
- Coombs+
- Agglutination
How can babesia be dx on microscopy ? Sensitivity?
- low sensitivty
- not recommended as sole screening test
> pear shaped, pyriform intraerythrocytic organisms
How can babesia be dx on PCR?
- high sensitivity
- broad-range Babesia PC
- species identification possible using species specific PCR/sequencing
How can babesia be dx on serology?
- usually indirect flueorescence Ab test/ELISA
Tx babesia?
- anibabesial drug (Imidocarb dipropionate)
- large forms: rapid clinical repsonse
- small forms: clinical and parastiological cure uncommon - clincial relapse can occour
Canine erhlichia and anaplasma spp?
> monocytic - Ehrlichia Canis - Ehrclichia Chaffeensis (causes human monocyte ehrlichiosis, transmited by Ambylomma americanum, molecular evidence of canine infections) > thrombocytic - Anaplasma platys > Granulocytic - Anaplasma phagocytophilum - Ehrlichia Erwingii
is erhlichia zoonotic?
NO deffo not only candis
Outline pathogensis of ehrlichia canis
> acute [1-4weeks]
- vasculitis and immune destruction -> thrombocytonpenia and coagulopathy
- multi-systemic signs
- spleen and LN enlargement
- CNS/ocular signs
subclinical carriers possible [months- years]
chronic [classical form of the dz]
- BM destruction -> pancytopenia (can present similar to acute)
Dx ehrlichia canis?
- morulae in monocytes in blood smear or macrophages from tssue aspirates (spleen, lung, LN)
- thrombocytonpeni/pancytopenia
- IFA/ELISA
Tx/prevention of ehrlichia? Vax?
- Tetracyclines for 28d
- Chloramphenicol
- No vax
- Chemoprophylaxis
- Tick-control
Clinical signs of A. Phagocytpohilum in dogs?
- mild/mod thrombocytopenia
- lymphopenia
- mild anaemia
- natural chronic infection has not been seen
- impaired PMN fucntion pdf 2* infection
WHich species are affected by a. phagocytophilum?
- dogs
- cats rarely
- zoonotic rarelyl and unclear if domestic animals pose zoonotic risk (role as sentinels)
What does Borellia cause?
- Lyme disease
What lifecycle does Borellia Burgdfori ahve?
- sylvatic (tick wildlife )
- dogs incidental hosts
- no evidence that companion animals are a source of infection for people but can import infected ticks
Which pathogenic genospecies of borellia exist?
- B. afzelii (skin )
- B. garinii (CNS)
- B. Burgdorferi sensu stricto (only pathogenic sp. found in N. America, present some parts of Europe and can cause neurological/arthritic complications)
What is the most prevalent tick-transmitted infection in temperate areas of Europe, N. America and Asia?
- Lyme disease
and increasing prevalence
Clinical signs of Lyme disease?
- Erythema migrans (bullseye)
- later clinical signs involve skin, nervous, musculoskeletal systems (polyarthropathy etc.)
Prevalence of infected ticks on dogs in UK? Europe?
- 0.5% UK
- ~12% europe
> esp humid areas eg. woodland
Otimal habitat for ticks?
- humid eg. woodland
What is common with Borreliosis in dogs?
- co-infection eg. a. phagocytophilia
Commonest signs of Borreliosis in dogs?
- lethargy, anorexia, pyrexia
- inflammaotry polyarthritis
- lymphadednopathy
- PLG
Dx Borreliosis
> complicated
- no pathognomic test
- asymptomatic seroconversion common
- microscopic/genetic detection often not possible
Tx Borreliosis in dogs?
- Empirical Abx
- Doxycycline/ amoxicillin
ROutes of transmission of Leishmania possible?
- Phlebotomous vector
- venereal
- blood products
- direct contact (skin wounds)
Which is the most important species in Europe of Leishmania?
- L. infantum (endemic south europe)
Prevalence of Leishmania
- p to 70-90% some areas Meditterranean basin eg. Spanish Balearic Islands
How canprevalnce be monitored/tested?
- PCR and serology (> than disease)
Highest risk time for infection with Leishmania?
- travelling to endemic areas in high sandfly ties (summer March-NoV)
What is the situation in the UK of Leishmania status?
- infected dogs are potential reservoir
- BUT require a competant vector (climatic changes would allow this)
Outline leishmania life cycle ECHO 30mins
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Target cell of leishmania?
- macrophages -> systemic infection in hemolymphatic organs
- parasite persistence -> chonic infection
Pathogensis of Leishamnia?
- systemic infection in hemolymphatic organs
- parasitic persistence can -> chronic infection
- protective immunity mediated by T cells (Th1)
- signs may develop months-years after infection (>7yrs)
What does outcome/disease progression depend on in Leishmania?
Types of immune response mounted
- Th1 clears infections
- Th2 inapprooprate antibody not helpful!
- endemic/naive status
- age (2-4 and >7yrs more susceptible)
- breed
- nutrition
- concurrent dz
- immunosuppression
CLnical sings of Leishmania?
- emaciation and malaise
- visceral and cutaneous signs
- skin disease (mucocutaneous junction, erosive/ulcerative, hyperkeratosis)
- lymphadenomegaly/splenomegaly
- fluctuating signs
Dx of Leishmania? Purposes of Dx?
> confirm dz or screen at risk healthy dogs/blood donors
- demonstrate parasite
- definitive dx, specificity 100%, senstiivity lower - Serology
- high Ab titre (plus clinical signs) - PCR gold standard
- BM, LN, spleen, skin
- sensitive esp early infection - clinpath
- hyperglobunlinaemia (ineffective Th2 B cell response)
- decease abl:glob ratio
- thrombocytopenia
- non-regenerative anaemia
- proteinuria
Tx Leishmania?
> anti-leishmanial drugs
-Meglumine antimoniate (“Glucantime”) + Allopurinol
- prolonged tx
- often give clinical remission but persistnet parasitaemia
- NOT LIC UK needs import lic
consider PTS (zoonotic risk, especially where endemic)
Prevention of Leishmania?
- avoid sandflies
- topical insecticides
> imidacloprid/permethrin spoton (apply 2d before travelling)
> Deltamethrin impregnated collars (apply 2w before travelling) - vax available
Forms of human infections leishmania? Who is at risk? What is the 1* route of transmission?
- cutaneous/visceral [fatal]/mucocutaneous/self-limiting or subclin dz
- at risk young and immunosuppressed
- 1* route of infection = transmission by sandflies from dogs, direct contact? Poss
- population level correlation between human and canine dz prevalence but dog ownership not a risk factor (indivdual level)
Where is dirofilaria immitis endemic? What is the vector and what does it caause?
- endemic europe, USA, Australia (Not UK yet)
- mosquito vector
What does dirofilaria immitis cause?
> Heart worm
- occupies R heart and PAs
- clinical signs : coughing, dyspnoea, v excercise tolerance
Whcih species more resistant to heart worm?
- cats but disease can still occour
- ZOONOTIC
Is heart worm zoonotic?
YES
How long is the PPP for heart worm?
~6m
Prophlyaxis for heart worm for animals travelling abroad
- monthly selamectin (Stronghold)
- monthly milbemycin (Program +/Milbemax)
- monthly moxidectin (Advocate)
Tx Dirofilaria Immitis?
- Symptomatic tx (steroids, tx CHF)
- Adulticide tx (melarsomine)
- Microfilarial tx (levamisole, ivermectin, milbemycin)
WHat is Bartonella?
- small G- hemotropic bacteria
- transmitted by fleas (+- ticks)
- Bartonella henselae most common in cats (difernet host-adapted species within Bartonella genus)
- Widespread but cats don’t get disease
- ZOONOTIC
What does BArtonella cause?
Cat scratch disease Bartonellosis
- swollen LNs if immunocompetent, bacillary angiomatosis if immunocompromised
Main reasons for complicated diagnosis of arthropod transmitted dz?
- long incubation period
- asymptomatic states
Which breed is pdf severe reactions to Ehrlichia?
GSDs
Are zoonotic dz always of clinical relevance to veterinary spp?
May be of low (Bartonella) or high (Leishmania) relevance
Are zoonotic diseases always directly transmitted?
- direclty (Cat-scratch dz)
- indiretly via vector
What are vectorborne dz?
- dz caused by parsites, bacteria or viruses transmitted by the bite of hematophagous arthropods
