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
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 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.
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
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:
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.
Dirofilariosis in humans.
D. repens:
* Subcutaneous nodules, adult worms under
skin of eyelid, eyes (rare)
D.immitis causes pulmonary nodules.
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 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%)
A. Vasorum Treatment
imidacloprid / moxidectin (advantage, advocate)
milbemycin (interceptor)
fenbendazole (panacur)
