Selected canine vector-borne diseases Flashcards
Canine babesiosis is a
(blood) protozoal, vector-borne disease caused by Babesia spp.
Not zoonotic. Worldwide importance. Common in central to south Europe.
Protozoa based on morphology:
* Small: B.gibsoni; B.microti like spp.
* Large: B. canis; B.rossi; B.vogeli
Canine babesiosis is spread by
ticks such as
- Dermacentor reticulatus
- Rhipicephalus sanguineus
- Haemaphysalis spp
Protozoa based on morphology:
* Small: B.gibsoni; B.microti like spp.
* Large: B. canis; B.rossi; B.vogeli
Feline babesiosis is caused by: (2)
B. felis; B. cati
Clinical signs are rare in cats, typically only when concurrent disease.
Human babesiosis is caused by:
- Rare
- transmitted by Ixodes ricinus (castor bean tick)
Life cycle of Babesia spp.
tick is infected by ingestion of RBCs containing Babesia merozoites
Babesia matures in tick
dog is infected with sporozoites after tick bite
babesia develops into trophozoites in dog host
RBCs are infected by merozoites formed through asexual repro.
Babesia reproduces in
ticks and RBCs
hangs out in salivary glands of ticks
mortality of babesiosis up to
30%
IP of babesia spp.
10-21 days
In addition to tick transmission, babesiosis can be transmitted via:
- blood transfusions; through wounds; transplacental
- saliva or blood ingestion
Common clinical signs of babesiosis in animals.
pale MMs
depression & weakness
tachycardia + tachypnea
anorexia
fever
pigmenturia
splenomegaly
Clinical signs of babesiosis in complicated cases.
Diagnosing babesiosis, do these first.
Consider the season dependent on your location.
Anamnesis:
- travelling
- ticks sighted or not
- use of antiparasitics (when and how used?)
Hematologic changes in babesiosis:
- Anemia
- Intra-erythrocytic parasites in sample from regular draw
- Thrombocytopenia
- Leukocytosis
- In more chronic cases (low burden infections); do a Blood smear from peripheral capillary blood: e.g. Ear or nail.
Biochemical changes in babesiosis:
may be WNL
Possible:
* Elevation of liver and kidney enzymes
* High bilirubin
* High lactate
Acute phase protein measurement can be considered.
Urinalysis in babesiosis:
usually bilirubinuria
macroscopically often times brown
Imaging in babesiosis may reveal:
splenomegaly
but not always and not specific for babesiosis either.
a splenectomized dog is more susceptible to adverse side effects from babesiosis as the spleen is important for immunity.
Specific biochemical analyses for babesiosis diagnosis?
longer term cases: serology ABs toward babesia
acute cases: PCR for babesia DNA
Most pathogenic Babesia spp.? (2)
B.rossi; B.vogeli
are large babesia
Prognostic factors in non-survivors of babesiosis:
Main ones:
* High lactate
* Hypoglycemia
Also:
* High phosphate
* High triglycerides
- Anemia
- Thrombocytopenia
- Leucopenia
- Hypoproteinemia
Treatment of babesiosis.
Main purpose is to eliminate the parasite. Helps to know what species it is, more tailored approach to drugs.
- Imidocarb dipropionate (B.canis)
- Diminazene aceturate
- Atovaquone and azithromycin combined
- Combination of different antibiotics- still need more research.
- Treatment of anemia (blood transfusion)
- Supportive care for complicated cases
- Clinical improvement in 24-72h- in most cases.
Prevention of babesiosis.
- Regular checking and combing the animals fur. Attachment needed for at least 48h before Babesia transmission occurs (but note that other tick-borne disease are faster).
Use of antiparasitics:
External
* Permethrin (toxic to cats)
* Fipronile
* Flumethrin + propoxur
Internal
* Afoxolaner
* Fluralaner
* Sarolaner
- Blood donors are not checked for Babesia in all countries.
- Vaccines? (1 was on the market previously but no longer due to efficiency issues)
- Vaccine Pirodog (Merial) against B. canis
Canine dirofilarioses is caused by
- Dirofilaria immitis (cardiopulmonary infection)
& - Dirofilaria repens (less acute, more chronic - subcutaneous dirofilariosis)
common name: heartworm
Nature of disease with Dirofilaria immitis
- Canine and feline cardiopulmonary
dirofilariosis - In dogs serious and potentially life-threatening disease
Nature of disease with Dirofilaria repens
Canine and feline subcutaneous
dirofilariosis
prognosis much better than with D.immitis
Life cycle of Dirofilaria spp.
Takes up to 9 months in immitis, D. repens a little less, like 7m.
- Female mosquitoes spread dirofilaria!
- Release L3 through the bug bite wound
- Pre-adult worms move to pulmonary arteries and right ventricle
- This takes 50-60 days
- Mature female releases microfilariae into
bloodstream - Adults can live up to 7 years
- Microfilariae up to 2 years
- Microfilariae infect the mosquito
D. immitis stays in the pulmonary arteries
D. repens travels to the subcut tissues
D.immitis epidemiology: which species does it affect?
Affects wild and domestic canines and felines around the world.
Is heartworm zoonotic?
Yes, D.immitis is zoonotic! Uh oh!
D.immitis clinical signs
Cardiopulmonary clinical signs first.
Usually chronic progression.
* Cough
* Exercise intolerance
* Collapse
As the right-heart begins to fail:
* Ascites
* Peripheral edemas
* Hydrothorax
Severe:
* Dysuria
* Severe respiratory distress
* Epistaxis
* Hemoptysis (bloody sputum)
* Cachexia
* Icterus
D.immitis diagnostics
General:
- X-rays of chest
- cardiac U/S
- blood smear (image of microfilaria on microscopy, make several smears to catch them)
in house 4DX-snap antigen test
Specific:
- serology
- PCR
- modified knot test or filtration test
Describe the Knott test for microfilariae.
The preferred test is the modified Knott’s test, which involves using a centrifuge (a machine that spins the sample very quickly in a small circle) to concentrate the microfilariae.
Another common test is the filter test, which involves passing the sample through a very fine filter that traps the microfilariae. In both tests, microfilariae are detected and identified using a microscope.
How to tell D.repens from D.immitis.
D.repens is longer than D. immitis
Head shape very slightly different.
D.repens has a curved tail,
D.immitis has a straight tail.
Knott test and antigen test used in combination.
The Knott’s Technique detects circulating microfilariae and is used for the identification of Dirofilaria immitis microfilariae. It is the only microfilarial test that allows differentiation between Dirofilaria immitis and other filarial parasites.
Antigen test can cross-react with other nematode species. Confirm species by finding & identifying microfilariae.
The 4DX snap test can give you cross-reactions for
Angiostrongylus vasorum
Spirocerca lupi (Beetles; Oesophagus- sarcomas)
Acantocheilonema reconditum (Fleas, lice, ticks; Connective tissue)
D.immitis treatment
Best treatment is regular prevention:
* Milbemycin oxime
* Moxidectin
* Selamectin
* Ivermectin
- Adulticide therapy: melarsomine dihydrochloride (requires special license)
Supportive treatment:
* Glucocorticosteroids
* Antibiotics- doxycycline
- Surgical intervention only in certain cases.
- Exercise restriction!
- Cost! Expensive!
What drug is used to treat adult D.immitis?
Adulticide therapy: melarsomine dihydrochloride
requires special license
D.immitis prognosis
- Depending on the diagnosis time
- Depending on the case
- From good to guarded
Cats and heartworm.
Can catch it but are usually subclinical.
Treatment of D.immitis in cats
Specific treatment not used due to high thromboembolism risk.
- Prednisolone- 2mg/kg q24 first 2w, then 0,5mg/kg every other day 2w,
discontinuing in 2w. - Doxycycline 10mg/kg q24 PO 3 weeks
- Prophylaxis is more important! image:
Ferrets and D.immitis.
- Can be infected
- Clinical signs are subtle
- Low parasitic burden
- Outside ferrets - prophylactic treatment?
Human signs of D.immitis.
Doesn’t develop to final stages in humans so they also don’t get microfilariae in the blood stream. They capsulize in the tissues of the lungs.
Cough
Chest pain
Fever
Pleural effusion
Surgical removal
No microfilariae
Dirofilaria repens development is similar to?
Explain it.
D.immitis.
- Adults move to subcutaneous tissue
- Can be found in abdominal cavity; within connective muscular fasciae.
Is Dirofilaria repens zoonotic?
Yes! And don’t forget it
“In our study only every third .vet knew
that it is zoonotic.”
“92% of human doctors did not know whether D. repens can infect humans”
D.repens clinical signs.
This disease has a chronic development-nature.
Multilocal nodular dermatitis
* Described as nodules around face region, but can also be elsewhere.
Prurigo papularis dermatitis
* Pruritus in animals
* Erythema
* Alopecia
* Papules
* Hyperkeratosis
Eye involvement
* Erythema of the eye
* Conjunctivitis
D.repens diagnostics
Opening lumps
FNAs
Identification of worm under mciroscope
Send worms for PCR
Similar diagnostic approaches as in D.immitis
D.repens treatment
Prevention!
Using same prevention drugs as in
D.immitis.
Antibacterial treatment where needed.
Removal of the worms from lumps.
D.repens prognosis
Usually pretty good (def not as bad as D.immitis)
Why are antibacterials used in Dirofilariae cases?
due to the Bacteria Wolbachia pipientis
* Intracellular bacteria
* Synbiotic relationship with D.immitis and
D.repens
* The Parasites provide the bactt. with amino acids
* Bacteria helps with embryogenesis and is
necessary in reproduction of the parasite.
This is why its recommended to have doxycycline treatment prior to treatment of grown parasites.
Dirofilariosis in humans.
D. repens:
* Subcutaneous nodules, adult worms under
skin of eyelid, eyes (rare)
D.immitis causes pulmonary nodules.
Canine angiostrongylosis is the differential diagnosis for…?
D.immitis
both are heartworms
D.immitis is zoonotic, A.vasorum is not.
Describe A.vasorum.
angiostrongylus vasorum or French heartworm, 1866
- Canine pulmonary angiostronylosis
- Nematode, Metastrongyloid
- reservoir is foxes
- also found in Finland though more rarely than further south
- It is NOT a zoonotic disease.
- Up to 2000s was considered endemic in
certain regions.
Recent research have shown:
* Has shown up in prev. undiagnosed regions.
* Prevalence has increased in endemic regions.
Becoming bigger problem.
Diagnostics for A.vasorum.
History and clinical signs:
Tend to be younger dogs under 1 year old.
Winter-spring period typical for clinical signs due to snails being more active.
Pulmonary signs most frequent.
- cough, dyspnea, exercise intolerance
Coagulopathies sometimes but less commonly.
- DIC, IMTP
- anemia, melena etc.
Cardiovascular signs not so common.
- murmurs, myocarditis, pale MMs etc.
Neuro signs documented
- due to coagulopathies
Imaging for A.vasorum.
chest Xrays
CT for lung damage
MRI for brain damage
cardiac echo
Blood analyses in A.vasorum cases may show:
- Anaemia
- Leucocytosis
- Eosinophilia
- Thrombocytopenia
- Hyperglobulinemia, hyperproteinemia
- Increased/prolonged PT and PTT (coag)
- Decrease in fibrinogen
- Increase of acute phase proteins
Diagnostics for confirming A.vasorum.
Fecal sample
* Baermann method
* L1 larvae
* 3 day samples
BAL
Molecular methods
* PCR- parasite DNA
Serology
* ELISA
* Western blot
* SNAP test: Angio detect- antigen test
(Sens 98,1% & spets 99,4%)
What types of Co-infections are common with A.vasorum?
2 most common:
* Borrelia burgdorferi
* Leishmania infantum
Also:
* Rickettsia conorii
* Babesia canis
A. Vasorum Treatment
imidacloprid / moxidectin (advantage, advocate)
milbemycin (interceptor)
fenbendazole (panacur)
Prognosis for A.vasorum infection.
Depends largely on the clinical signs.
Coagulopathy patients more severe.
Potencially life-threatening
